Xenogenesis in teleost fish through generation of germ-line chimeras by single primordial germ cell transplantation.

PubMed

Saito, Taiju; Goto-Kazeto, Rie; Arai, Katsutoshi; Yamaha, Etsuro

2008-01-01

Primordial germ cells (PGCs) are the only cells in developing embryos with the potential to transmit genetic information to the next generation. PGCs therefore have the potential to be of value for gene banking and cryopreservation, particularly via the production of donor gametes with germ-line chimeras. Currently, it is not clear how many PGCs are required for germ-line differentiation and formation of gonadal structures. In the present study, we achieved complete germ-line replacement between two related teleost species, the pearl danio (Danio albolineatus) and the zebrafish (Danio rerio), with transplantation of a single PGC into each host embryo. We isolated and transplanted a single PGC into each blastula-stage, zebrafish embryo. Development of host germ-line cells was prevented by an antisense dead end morpholino oligonucleotide. In many host embryos, the transplanted donor PGC successfully migrated toward the gonadal anlage without undergoing cell division. At the gonadal anlage, the PGC differentiated to form one normally sized gonad rather than the pair of gonads usually present. Offspring were obtained from natural spawning of these chimeras. Analyses of morphology and DNA showed that the offspring were of donor origin. We extended our study to confirm that transplanted single PGCs of goldfish (Carassius auratus) and loach (Misgurnus anguillicaudatus) can similarly differentiate into sperm in zebrafish host embryos. Our results show that xenogenesis is realistic and practical across species, genus, and family barriers and can be achieved by the transplantation of a single PGC from a donor species.

Development, Characterization, and Pluripotency Analysis of Buffalo (Bubalus bubalis) Embryonic Stem Cell Lines Derived from In Vitro–Fertilized, Hand-Guided Cloned, and Parthenogenetic Embryos

PubMed Central

Shah, Syed Mohmad; Saini, Neha; Ashraf, Syma; Zandi, Mohammad; Manik, Radhey Sham; Singla, Suresh Kumar; Palta, Prabhat

2015-01-01

Abstract We present the derivation, characterization, and pluripotency analysis of three buffalo embryonic stem cell (buESC) lines, from in vitro–fertilized, somatic cell nuclear–transferred, and parthenogenetic blastocysts. These cell lines were developed for later differentiation into germ lineage cells and elucidation of the signaling pathways involved. The cell lines were established from inner cell masses (ICMs) that were isolated manually from the in vitro–produced blastocysts. Most of the ICMs (45–55%) resulted in formation of primary colonies that were subcultured after 8–10 days, leading subsequently to the formation of three buESC lines, one from each blastocyst type. All the cell lines expressed stem cell markers, such as Alkaline Phosphatase, OCT4, NANOG, SSEA1, SSEA4, TRA-1-60, TRA-1-81, SOX2, REX1, CD-90, STAT3, and TELOMERASE. They differentiated into all three germ layers as determined by ectodermal, mesodermal, and endodermal RNA and protein markers. All of the cell lines showed equal expression of pluripotency markers as well as equivalent differentiation potential into all the three germ layers. The static suspension culture–derived embryoid bodies (EBs) showed greater expression of all the three germ layer markers as compared to hanging drop culture–derived EBs. When analyzed for germ layer marker expression, EBs derived from 15% fetal bovine serum (FBS)-based spontaneous differentiation medium showed greater differentiation across all the three germ layers as compared to those derived from Knock-Out Serum Replacement (KoSR)-based differentiation medium. PMID:26168169

Developmental biotechnology for aquaculture, with special reference to surrogate production in teleost fishes

NASA Astrophysics Data System (ADS)

Yamaha, Etsuro; Saito, Taiju; Goto-Kazeto, Rie; Arai, Katsutoshi

2007-07-01

This review introduces surrogate production as a new technique for fish-seed production in aquaculture. Surrogate production in fish is a technique used to obtain the gametes of a certain genotype through the gonad of another genotype. It is achieved by inducing germ-line chimerism between different species during early development. Primordial germ cells (PGCs) are the key material of this technique to induce germ-line chimera. In several species, it has been reported that PGCs differentiated from the blastomeres inherited some maternally supplied mRNA located in the terminal regions of the early cleavage furrows. PGCs from donor species (or strains) are isolated and transplanted into host species to induce the germ-line chimera. Four methods for inducing germ-line chimera are described: blastomere transplantation, blastoderm-graft transplantation, transplantation of PGC from the genital ridge, and transplantation visualised PGC with GFP fluorescence. Several problems preventing the successful induction of germ-line chimera in various fish species are discussed. Surrogate production, however, opens the possibility of efficient fish-seed production and effective breeding and transfer of biodiversity to an aquaculture strain. Conservation and efficient utilisation of genetic resources will be achieved through surrogate production combined with the cryopreservation of PGCs.

Sexual dimorphism in parental imprint ontogeny and contribution to embryonic development.

PubMed

Bourc'his, Déborah; Proudhon, Charlotte

2008-01-30

Genomic imprinting refers to the functional non-equivalence of parental genomes in mammals that results from the parent-of-origin allelic expression of a subset of genes. Parent-specific expression is dependent on the germ line acquisition of DNA methylation marks at imprinting control regions (ICRs), coordinated by the DNA-methyltransferase homolog DNMT3L. We discuss here how the gender-specific stages of DNMT3L expression may have influenced the various sexually dimorphic aspects of genomic imprinting: (1) the differential developmental timing of methylation establishment at paternally and maternally imprinted genes in each parental germ line, (2) the differential dependence on DNMT3L of parental methylation imprint establishment, (3) the unequal duration of paternal versus maternal methylation imprints during germ cell development, (4) the biased distribution of methylation-dependent ICRs towards the maternal genome, (5) the different genomic organization of paternal versus maternal ICRs, and finally (6) the overwhelming contribution of maternal germ line imprints to development compared to their paternal counterparts.

A functional Bucky ball-GFP transgene visualizes germ plasm in living zebrafish.

PubMed

Riemer, Stephan; Bontems, Franck; Krishnakumar, Pritesh; Gömann, Jasmin; Dosch, Roland

2015-01-01

In many animals, the germline is specified by maternal RNA-granules termed germ plasm. The correct localization of germ plasm during embryogenesis is therefore crucial for the specification of germ cells. In zebrafish, we previously identified Bucky ball (Buc) as a key regulator of germ plasm formation. Here, we used a Buc antibody to describe its continuous germ plasm localization. Moreover, we generated a transgenic Buc-GFP line for live imaging, which visualizes germ plasm from its assembly during oogenesis up to the larval stages. Live imaging of Buc-GFP generated stunning movies, as they highlighted the dynamic details of germ plasm movements. Moreover, we discovered that Buc was still detected in primordial germ cells 2 days after fertilization. Interestingly, the transgene rescued buc mutants demonstrating genetically that the Buc-GFP fusion protein is functional. These results show that Buc-GFP exerts all biochemical interactions essential for germline development and highlight the potential of this line to analyze the molecular regulation of germ plasm formation. Copyright © 2015 Elsevier B.V. All rights reserved.

vasa and piwi are required for mitotic integrity in early embryogenesis in the spider Parasteatoda tepidariorum.

PubMed

Schwager, Evelyn E; Meng, Yue; Extavour, Cassandra G

2015-06-15

Studies in vertebrate and invertebrate model organisms on the molecular basis of primordial germ cell (PGC) specification have revealed that metazoans can specify their germ line either early in development by maternally transmitted cytoplasmic factors (inheritance), or later in development by signaling factors from neighboring tissues (induction). Regardless of the mode of PGC specification, once animal germ cells are specified, they invariably express a number of highly conserved genes. These include vasa and piwi, which can play essential roles in any or all of PGC specification, development, or gametogenesis. Although the arthropods are the most speciose animal phylum, to date there have been no functional studies of conserved germ line genes in species of the most basally branching arthropod clade, the chelicerates (which includes spiders, scorpions, and horseshoe crabs). Here we present the first such study by using molecular and functional tools to examine germ line development and the roles of vasa and piwi orthologues in the common house spider Parasteatoda (formerly Achaearanea) tepidariorum. We use transcript and protein expression patterns of Pt-vasa and Pt-piwi to show that primordial germ cells (PGCs) in the spider arise during late embryogenesis. Neither Pt-vasa nor Pt-piwi gene products are localized asymmetrically to any embryonic region before PGCs emerge as paired segmental clusters in opisthosomal segments 2-6 at late germ band stages. RNA interference studies reveal that both genes are required maternally for egg laying, mitotic progression in early embryos, and embryonic survival. Our results add to the growing body of evidence that vasa and piwi can play important roles in somatic development, and provide evidence for a previously hypothesized conserved role for vasa in cell cycle progression. Copyright © 2014 Elsevier Inc. All rights reserved.

Pluripotent stem cells and reprogrammed cells in farm animals.

PubMed

Nowak-Imialek, Monika; Kues, Wilfried; Carnwath, Joseph W; Niemann, Heiner

2011-08-01

Pluripotent cells are unique because of their ability to differentiate into the cell lineages forming the entire organism. True pluripotent stem cells with germ line contribution have been reported for mice and rats. Human pluripotent cells share numerous features of pluripotentiality, but confirmation of their in vivo capacity for germ line contribution is impossible due to ethical and legal restrictions. Progress toward derivation of embryonic stem cells from domestic species has been made, but the derived cells were not able to produce germ line chimeras and thus are termed embryonic stem-like cells. However, domestic animals, in particular the domestic pig (Sus scrofa), are excellent large animals models, in which the clinical potential of stem cell therapies can be studied. Reprogramming technologies for somatic cells, including somatic cell nuclear transfer, cell fusion, in vitro culture in the presence of cell extracts, in vitro conversion of adult unipotent spermatogonial stem cells into germ line derived pluripotent stem cells, and transduction with reprogramming factors have been developed with the goal of obtaining pluripotent, germ line competent stem cells from domestic animals. This review summarizes the present state of the art in the derivation and maintenance of pluripotent stem cells in domestic animals.

Germ line mechanics – and unfinished business

PubMed Central

Wessel, Gary M.

2016-01-01

Primordial germ cells are usually made early in the development of an organism. These are the mother of all stem cells that are necessary for propagation of the species, yet use highly diverse mechanisms between organisms. How they are specified, and when and where they form, are central to developmental biology. Using diverse organisms to study this development is illuminating for understanding the mechanics these cells use in this essential function, and for identifying the breadth of evolutionary changes that have occurred between species. This essay emphasizes how echinoderms may contribute to the patch-work quilt of our understanding of germ line formation during embryogenesis. PMID:26970000

Germ Line Mechanics--And Unfinished Business.

PubMed

Wessel, Gary M

2016-01-01

Primordial germ cells are usually made early in the development of an organism. These are the mother of all stem cells that are necessary for propagation of the species, yet use highly diverse mechanisms between organisms. How they are specified, and when and where they form, are central to developmental biology. Using diverse organisms to study this development is illuminating for understanding the mechanics these cells use in this essential function and for identifying the breadth of evolutionary changes that have occurred between species. This essay emphasizes how echinoderms may contribute to the patchwork quilt of our understanding of germ line formation during embryogenesis. © 2016 Elsevier Inc. All rights reserved.

Epigenetic Transgenerational Effects of Endocrine Disruptors on Male Reproduction

PubMed Central

Guerrero-Bosagna, Carlos M.; Skinner, Michael K.

2013-01-01

Endocrine-disrupting chemicals generally function as steroid receptor signaling antagonists or agonists that influence development to promote adult-onset disease. Exposure to the endocrine disruptors during the initiation of male reproductive tract development interferes with the normal hormonal signaling and formation of male reproductive organs. In particular, exposure to the endocrine disruptor vinclozolin promotes transgenerational transmission of adult-onset disease states such as male infertility, increased frequencies of tumors, prostate disease, kidney diseases, and immune abnormalities that develop as males age. An epigenetic change in the germ line would be involved in the transgenerational transmission of these induced phenotypes. Nevertheless, other studies have also reported transgenerational transmission of induced epigenetic changes, without altering the germ line. Here we propose a nomenclature to help clarify both cases of transgenerational epigenetic transmission. An intrinsic epigenetic transgenerational process would require a germ-line involvement, a permanent alteration in the germ cell epigenome, and only one exposure to the environmental factor. An extrinsic epigenetic transgenerational process would involve an epigenetic alteration in a somatic tissue and require exposure at each generation to maintain the transgenerational phenotype. PMID:19711250

Identification of genes expressed in the hermaphrodite germ line of C. elegans using SAGE

PubMed Central

Wang, Xin; Zhao, Yongjun; Wong, Kim; Ehlers, Peter; Kohara, Yuji; Jones, Steven J; Marra, Marco A; Holt, Robert A; Moerman, Donald G; Hansen, Dave

2009-01-01

Background Germ cells must progress through elaborate developmental stages from an undifferentiated germ cell to a fully differentiated gamete. Some of these stages include exiting mitosis and entering meiosis, progressing through the various stages of meiotic prophase, adopting either a male (sperm) or female (oocyte) fate, and completing meiosis. Additionally, many of the factors needed to drive embryogenesis are synthesized in the germ line. To increase our understanding of the genes that might be necessary for the formation and function of the germ line, we have constructed a SAGE library from hand dissected C. elegans hermaphrodite gonads. Results We found that 4699 genes, roughly 21% of all known C. elegans genes, are expressed in the adult hermaphrodite germ line. Ribosomal genes are highly expressed in the germ line; roughly four fold above their expression levels in the soma. We further found that 1063 of the germline-expressed genes have enriched expression in the germ line as compared to the soma. A comparison of these 1063 germline-enriched genes with a similar list of genes prepared using microarrays revealed an overlap of 460 genes, mutually reinforcing the two lists. Additionally, we identified 603 germline-enriched genes, supported by in situ expression data, which were not previously identified. We also found >4 fold enrichment for RNA binding proteins in the germ line as compared to the soma. Conclusion Using multiple technological platforms provides a more complete picture of global gene expression patterns. Genes involved in RNA metabolism are expressed at a significantly higher level in the germ line than the soma, suggesting a stronger reliance on RNA metabolism for control of the expression of genes in the germ line. Additionally, the number and expression level of germ line expressed genes on the X chromosome is lower than expected based on a random distribution. PMID:19426519

A Role for Caenorhabditis elegans Importin IMA-2 in Germ Line and Embryonic Mitosis

PubMed Central

Geles, Kenneth G.; Johnson, Jeffrey J.; Jong, Sena; Adam, Stephen A.

2002-01-01

The importin α family of nuclear-cytoplasmic transport factors mediates the nuclear localization of proteins containing classical nuclear localization signals. Metazoan animals express multiple importin α proteins, suggesting their possible roles in cell differentiation and development. Adult Caenorhabditis elegans hermaphrodites express three importin α proteins, IMA-1, IMA-2, and IMA-3, each with a distinct expression and localization pattern. IMA-2 was expressed exclusively in germ line cells from the early embryonic through adult stages. The protein has a dynamic pattern of localization dependent on the stage of the cell cycle. In interphase germ cells and embryonic cells, IMA-2 is cytoplasmic and nuclear envelope associated, whereas in developing oocytes, the protein is cytoplasmic and intranuclear. During mitosis in germ line cells and embryos, IMA-2 surrounded the condensed chromosomes but was not directly associated with the mitotic spindle. The timing of IMA-2 nuclear localization suggested that the protein surrounded the chromosomes after fenestration of the nuclear envelope in prometaphase. Depletion of IMA-2 by RNA-mediated gene interference (RNAi) resulted in embryonic lethality and a terminal aneuploid phenotype. ima-2(RNAi) embryos have severe defects in nuclear envelope formation, accumulating nucleoporins and lamin in the cytoplasm. We conclude that IMA-2 is required for proper chromosome dynamics in germ line and early embryonic mitosis and is involved in nuclear envelope assembly at the conclusion of mitosis. PMID:12221121

Gain-of-function mutations of fem-3, a sex-determination gene in Caenorhabditis elegans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barton, M.K.; Schedl, T.B.; Kimble, J.

1987-01-01

The authors have isolated nine gain-of-function (gf) alleles of the sex-determination gene fem-3 as suppressors of feminizing mutations in fem-1 and fem-2. The wild type fem-3 gene is needed for spermatogenesis in XX self-fertilizing hermaphrodites and for male development in both soma and germ line of XO animals. Loss-of-function alleles of fem-3 transform XX and XO animals into females (spermless hermaphrodites). In contrast, fem-3 (gf) alleles masculinize only one tissue, the hermaphrodite germ line. Thus, XX fem-3 (gf) mutant animals have a normal hermaphrodite soma, but the germ line produces a vast excess of sperm and no oocytes. All ninemore » fem-3 (gf) alleles are temperature sensitive. The temperature-sensitive period is from late L4 to early adult, a period just preceding the first signs of oogenesis. The finding of gain-of-function alleles which confer a phenotype opposite to that of loss-of-function alleles supports the idea that fem-3 plays a critical role in germ-line sex determination. Furthermore, the germ-line specificity of the fem-3 (gf) mutant phenotype and the late temperature-sensitive period suggest that, in the wild-type XX hermaphrodite, fem-3 is negatively regulated so that the hermaphrodite stops making sperm and starts making oocytes. Temperature shift experiments also show that, in the germ line, sexual commitment appears to be a continuing process. Spermatogenesis can resume even after oogenesis has begun, and oogenesis can be initiated much later than normal.« less

Environmentally Induced Transgenerational Epigenetic Reprogramming of Primordial Germ Cells and the Subsequent Germ Line

PubMed Central

Skinner, Michael K.; Haque, Carlos Guerrero-Bosagna M.; Nilsson, Eric; Bhandari, Ramji; McCarrey, John R.

2013-01-01

A number of environmental factors (e.g. toxicants) have been shown to promote the epigenetic transgenerational inheritance of disease and phenotypic variation. Transgenerational inheritance requires the germline transmission of altered epigenetic information between generations in the absence of direct environmental exposures. The primary periods for epigenetic programming of the germ line are those associated with primordial germ cell development and subsequent fetal germline development. The current study examined the actions of an agricultural fungicide vinclozolin on gestating female (F0 generation) progeny in regards to the primordial germ cell (PGC) epigenetic reprogramming of the F3 generation (i.e. great-grandchildren). The F3 generation germline transcriptome and epigenome (DNA methylation) were altered transgenerationally. Interestingly, disruptions in DNA methylation patterns and altered transcriptomes were distinct between germ cells at the onset of gonadal sex determination at embryonic day 13 (E13) and after cord formation in the testis at embryonic day 16 (E16). A larger number of DNA methylation abnormalities (epimutations) and transcriptional alterations were observed in the E13 germ cells than in the E16 germ cells. These observations indicate that altered transgenerational epigenetic reprogramming and function of the male germline is a component of vinclozolin induced epigenetic transgenerational inheritance of disease. Insights into the molecular control of germline transmitted epigenetic inheritance are provided. PMID:23869203

In vitro gamete derivation from pluripotent stem cells: progress and perspective.

PubMed

Nagano, Makoto C

2007-04-01

Germ cells constitute a highly specialized cell population that is indispensable for the continuation and evolution of the species. Recently, several research groups have shown that these unique cells can be produced in vitro from pluripotent stem cells. Furthermore, live births of offspring using induced germ cells have been reported in one study. These results suggest that it may be possible to investigate germ cell development ex vivo and to establish novel reproductive technologies. To this end, it is critical to assess if gamete induction processes in vitro faithfully recapitulate normal germ cell development in vivo. Here, this issue is discussed with a focus on the germ line specification and the sex-specific development of pre- and postnatal germ cells. The aim of this paper is to concisely summarize the past progress and to present some future issues for the investigation into in vitro gamete production from pluripotent stem cells.

Piwi Is Required in Multiple Cell Types to Control Germline Stem Cell Lineage Development in the Drosophila Ovary

PubMed Central

Ma, Xing; Wang, Su; Do, Trieu; Song, Xiaoqing; Inaba, Mayu; Nishimoto, Yoshiya; Liu, Lu-ping; Gao, Yuan; Mao, Ying; Li, Hui; McDowell, William; Park, Jungeun; Malanowski, Kate; Peak, Allison; Perera, Anoja; Li, Hua; Gaudenz, Karin; Haug, Jeff; Yamashita, Yukiko; Lin, Haifan; Ni, Jian-quan; Xie, Ting

2014-01-01

The piRNA pathway plays an important role in maintaining genome stability in the germ line by silencing transposable elements (TEs) from fly to mammals. As a highly conserved piRNA pathway component, Piwi is widely expressed in both germ cells and somatic cells in the Drosophila ovary and is required for piRNA production in both cell types. In addition to its known role in somatic cap cells to maintain germline stem cells (GSCs), this study has demonstrated that Piwi has novel functions in somatic cells and germ cells of the Drosophila ovary to promote germ cell differentiation. Piwi knockdown in escort cells causes a reduction in escort cell (EC) number and accumulation of undifferentiated germ cells, some of which show active BMP signaling, indicating that Piwi is required to maintain ECs and promote germ cell differentiation. Simultaneous knockdown of dpp, encoding a BMP, in ECs can partially rescue the germ cell differentiation defect, indicating that Piwi is required in ECs to repress dpp. Consistent with its key role in piRNA production, TE transcripts increase significantly and DNA damage is also elevated in the piwi knockdown somatic cells. Germ cell-specific knockdown of piwi surprisingly causes depletion of germ cells before adulthood, suggesting that Piwi might control primordial germ cell maintenance or GSC establishment. Finally, Piwi inactivation in the germ line of the adult ovary leads to gradual GSC loss and germ cell differentiation defects, indicating the intrinsic role of Piwi in adult GSC maintenance and differentiation. This study has revealed new germline requirement of Piwi in controlling GSC maintenance and lineage differentiation as well as its new somatic function in promoting germ cell differentiation. Therefore, Piwi is required in multiple cell types to control GSC lineage development in the Drosophila ovary. PMID:24658126

Sequence-specific epigenetic effects of the maternal somatic genome on developmental rearrangements of the zygotic genome in Paramecium primaurelia.

PubMed Central

Meyer, E; Butler, A; Dubrana, K; Duharcourt, S; Caron, F

1997-01-01

In ciliates, the germ line genome is extensively rearranged during the development of the somatic macronucleus from a mitotic product of the zygotic nucleus. Germ line chromosomes are fragmented in specific regions, and a large number of internal sequence elements are eliminated. It was previously shown that transformation of the vegetative macronucleus of Paramecium primaurelia with a plasmid containing a subtelomeric surface antigen gene can affect the processing of the homologous germ line genomic region during development of a new macronucleus in sexual progeny of transformed clones. The gene and telomere-proximal flanking sequences are deleted from the new macronuclear genome, although the germ line genome remains wild type. Here we show that plasmids containing nonoverlapping segments of the same genomic region are able to induce similar terminal deletions; the locations of deletion end points depend on the particular sequence used. Transformation of the maternal macronucleus with a sequence internal to a macronuclear chromosome also causes the occurrence of internal deletions between short direct repeats composed of alternating thymines and adenines. The epigenetic influence of maternal macronuclear sequences on developmental rearrangements of the zygotic genome thus appears to be both sequence specific and general, suggesting that this trans-nucleus effect is mediated by pairing of homologous sequences. PMID:9199294

Retroperitoneal dedifferentiated liposarcoma lacking MDM2 amplification in a patient with a germ line CHEK2 mutation.

PubMed

Sadri, Navid; Surrey, Lea F; Fraker, Douglas L; Zhang, Paul J

2014-04-01

Germ line mutations in genes that encode proteins involved in the DNA damage response predispose patients to a variety of tumors. Checkpoint kinase 2, encoded by the CHEK2 gene, is important in transducing the DNA damage response. Germ line CHEK2 mutations are seen in a subset of patients with a familial breast cancer and sarcoma phenotype. We report a case of retroperitoneal dedifferentiated liposarcoma in a 61-year-old female with germ line CHEK2 mutation. MDM2 gene amplification normally present and used to aid in the diagnosis of retroperitoneal dedifferentiated liposarcoma was absent in this case. Lack of MDM2 overexpression has similarly been reported in liposarcomas arising in patients with germ line TP53 mutations. We propose this case may highlight a nonamplified MDM2 phenotype in well- and dedifferentiated liposarcomas arising in patients with germ line mutations of genes involved in p53-associated DNA damage response pathways.

A germ cell determinant reveals parallel pathways for germ line development in Caenorhabditis elegans.

PubMed

Mainpal, Rana; Nance, Jeremy; Yanowitz, Judith L

2015-10-15

Despite the central importance of germ cells for transmission of genetic material, our understanding of the molecular programs that control primordial germ cell (PGC) specification and differentiation are limited. Here, we present findings that X chromosome NonDisjunction factor-1 (XND-1), known for its role in regulating meiotic crossover formation, is an early determinant of germ cell fates in Caenorhabditis elegans. xnd-1 mutant embryos display a novel 'one PGC' phenotype as a result of G2 cell cycle arrest of the P4 blastomere. Larvae and adults display smaller germ lines and reduced brood size consistent with a role for XND-1 in germ cell proliferation. Maternal XND-1 proteins are found in the P4 lineage and are exclusively localized to the nucleus in PGCs, Z2 and Z3. Zygotic XND-1 turns on shortly thereafter, at the ∼300-cell stage, making XND-1 the earliest zygotically expressed gene in worm PGCs. Strikingly, a subset of xnd-1 mutants lack germ cells, a phenotype shared with nos-2, a member of the conserved Nanos family of germline determinants. We generated a nos-2 null allele and show that nos-2; xnd-1 double mutants display synthetic sterility. Further removal of nos-1 leads to almost complete sterility, with the vast majority of animals without germ cells. Sterility in xnd-1 mutants is correlated with an increase in transcriptional activation-associated histone modification and aberrant expression of somatic transgenes. Together, these data strongly suggest that xnd-1 defines a new branch for PGC development that functions redundantly with nos-2 and nos-1 to promote germline fates by maintaining transcriptional quiescence and regulating germ cell proliferation. © 2015. Published by The Company of Biologists Ltd.

Biphasic adaptation to osmotic stress in the C. elegans germ line.

PubMed

Davis, Michael; Montalbano, Andrea; Wood, Megan P; Schisa, Jennifer A

2017-06-01

Cells respond to environmental stress in multiple ways. In the germ line, heat shock and nutritive stress trigger the assembly of large ribonucleoprotein (RNP) granules via liquid-liquid phase separation (LLPS). The RNP granules are hypothesized to maintain the quality of oocytes during stress. The goal of this study was to investigate the cellular response to glucose in the germ line and determine if it is an osmotic stress response. We found that exposure to 500 mM glucose induces the assembly of RNP granules in the germ line within 1 h. Interestingly, the RNP granules are maintained for up to 3 h; however, they dissociate after longer periods of stress. The RNP granules include processing body and stress granule proteins, suggesting shared functions. Based on several lines of evidence, the germ line response to glucose largely appears to be an osmotic stress response, thus identifying osmotic stress as a trigger of LLPS. Although RNP granules are not maintained beyond 3 h of osmotic stress, the quality of oocytes does not appear to decrease after longer periods of stress, suggesting a secondary adaptation in the germ line. We used an indirect marker of glycerol and observed high levels after 5 and 20 h of glucose exposure. Moreover, in gpdh-1;gpdh-2 germ lines, glycerol levels are reduced concomitant with RNP granules being maintained for an extended period. We speculate that increased glycerol levels may function as a secondary osmoregulatory adaptive response in the germ line, following a primary response of RNP granule assembly. Copyright © 2017 the American Physiological Society.

Bone Morphogenetic Protein (BMP) signaling in animal reproductive system development and function.

PubMed

Lochab, Amaneet K; Extavour, Cassandra G

2017-07-15

In multicellular organisms, the specification, maintenance, and transmission of the germ cell lineage to subsequent generations are critical processes that ensure species survival. A number of studies suggest that the Bone Morphogenetic Protein (BMP) pathway plays multiple roles in this cell lineage. We wished to use a comparative framework to examine the role of BMP signaling in regulating these processes, to determine if patterns would emerge that might shed light on the evolution of molecular mechanisms that may play germ cell-specific or other reproductive roles across species. To this end, here we review evidence to date from the literature supporting a role for BMP signaling in reproductive processes across Metazoa. We focus on germ line-specific processes, and separately consider somatic reproductive processes. We find that from primordial germ cell (PGC) induction to maintenance of PGC identity and gametogenesis, BMP signaling regulates these processes throughout embryonic development and adult life in multiple deuterostome and protostome clades. In well-studied model organisms, functional genetic evidence suggests that BMP signaling is required in the germ line across all life stages, with the exception of PGC specification in species that do not use inductive signaling to induce germ cell formation. The current evidence is consistent with the hypothesis that BMP signaling is ancestral in bilaterian inductive PGC specification. While BMP4 appears to be the most broadly employed ligand for the reproductive processes considered herein, we also noted evidence for sex-specific usage of different BMP ligands. In gametogenesis, BMP6 and BMP15 seem to have roles restricted to oogenesis, while BMP8 is restricted to spermatogenesis. We hypothesize that a BMP-based mechanism may have been recruited early in metazoan evolution to specify the germ line, and was subsequently co-opted for use in other germ line-specific and somatic reproductive processes. We suggest that if future studies assessing the function of the BMP pathway across extant species were to include a reproductive focus, that we would be likely to find continued evidence in favor of an ancient association between BMP signaling and the reproductive cell lineage in animals. Copyright © 2017 Elsevier Inc. All rights reserved.

Germ-Line Recombination Activity of the Widely Used hGFAP-Cre and Nestin-Cre Transgenes

PubMed Central

Zhang, Jiong; Dublin, Pavel; Griemsmann, Stephanie; Klein, Alexandra; Brehm, Ralph; Bedner, Peter; Fleischmann, Bernd K.; Steinhäuser, Christian; Theis, Martin

2013-01-01

Herein we demonstrate with PCR, immunodetection and reporter gene approaches that the widely used human Glial Fibrillary Acidic Protein (hGFAP)-Cre transgene exhibits spontaneous germ-line recombination activity in leading to deletion in brain, heart and tail tissue with high frequency. The ectopic activity of hGFAP-Cre requires a rigorous control. We likewise observed that a second widely used nestin-Cre transgene shows germ-line deletion. Here we describe procedures to identify mice with germ-line recombination mediated by the hGFAP-Cre and nestin-Cre transgenes. Such control is essential to avoid pleiotropic effects due to germ-line deletion of loxP-flanked target genes and to maintain the CNS-restricted deletion status in transgenic mouse colonies. PMID:24349371

Impact of gut microbiota on the fly's germ line.

PubMed

Elgart, Michael; Stern, Shay; Salton, Orit; Gnainsky, Yulia; Heifetz, Yael; Soen, Yoav

2016-04-15

Unlike vertically transmitted endosymbionts, which have broad effects on their host's germ line, the extracellular gut microbiota is transmitted horizontally and is not known to influence the germ line. Here we provide evidence supporting the influence of these gut bacteria on the germ line of Drosophila melanogaster. Removal of the gut bacteria represses oogenesis, expedites maternal-to-zygotic-transition in the offspring and unmasks hidden phenotypic variation in mutants. We further show that the main impact on oogenesis is linked to the lack of gut Acetobacter species, and we identify the Drosophila Aldehyde dehydrogenase (Aldh) gene as an apparent mediator of repressed oogenesis in Acetobacter-depleted flies. The finding of interactions between the gut microbiota and the germ line has implications for reproduction, developmental robustness and adaptation.

A Genomewide RNAi Screen for Genes That Affect the Stability, Distribution and Function of P Granules in Caenorhabditis elegans

PubMed Central

Updike, Dustin L.; Strome, Susan

2009-01-01

P granules are non-membrane-bound organelles found in the germ-line cytoplasm throughout Caenorhabditis elegans development. Like their “germ granule” counterparts in other animals, P granules are thought to act as determinants of the identity and special properties of germ cells, properties that include the unique ability to give rise to all tissues of future generations of an organism. Therefore, understanding how P granules work is critical to understanding how cellular immortality and totipotency are retained, gained, and lost. Here we report on a genomewide RNAi screen in C. elegans, which identified 173 genes that affect the stability, localization, and function of P granules. Many of these genes fall into specific classes with shared P-granule phenotypes, allowing us to better understand how cellular processes such as protein degradation, translation, splicing, nuclear transport, and mRNA homeostasis converge on P-granule assembly and function. One of the more striking phenotypes is caused by the depletion of CSR-1, an Argonaute associated with an endogenous siRNA pathway that functions in the germ line. We show that CSR-1 and two other endo-siRNA pathway members, the RNA-dependent RNA polymerase EGO-1 and the helicase DRH-3, act to antagonize RNA and P-granule accumulation in the germ line. Our findings strengthen the emerging view that germ granules are involved in numerous aspects of RNA metabolism, including an endo-siRNA pathway in germ cells. PMID:19805813

Female mice lack adult germ-line stem cells but sustain oogenesis using stable primordial follicles.

PubMed

Lei, Lei; Spradling, Allan C

2013-05-21

Whether or not mammalian females generate new oocytes during adulthood from germ-line stem cells to sustain the ovarian follicle pool has recently generated controversy. We used a sensitive lineage-labeling system to determine whether stem cells are needed in female adult mice to compensate for follicular losses and to directly identify active germ-line stem cells. Primordial follicles generated during fetal life are highly stable, with a half-life during adulthood of 10 mo, and thus are sufficient to sustain adult oogenesis without a source of renewal. Moreover, in normal mice or following germ-cell depletion with Busulfan, only stable, single oocytes are lineage-labeled, rather than cell clusters indicative of new oocyte formation. Even one germ-line stem cell division per 2 wk would have been detected by our method, based on the kinetics of fetal follicle formation. Thus, adult female mice neither require nor contain active germ-line stem cells or produce new oocytes in vivo.

Gonad establishment during asexual reproduction in the annelid Pristina leidyi.

PubMed

Özpolat, B Duygu; Bely, Alexandra E

2015-09-01

Animals that can reproduce by both asexual agametic reproduction and sexual reproduction must transmit or re-establish their germ line post-embryonically. Although such a dual reproductive mode has evolved repeatedly among animals, how asexually produced individuals establish their germ line remains poorly understood in most groups. We investigated germ line development in the annelid Pristina leidyi, a species that typically reproduces asexually by paratomic fission, intercalating a new tail and head in the middle of the body followed by splitting. We found that in fissioning individuals, gonads occur in anterior segments in the anterior-most individual as well as in new heads forming within fission zones. Homologs of the germ line/multipotency genes piwi, vasa, and nanos are expressed in the gonads, as well as in proliferative tissues including the posterior growth zone, fission zone, and regeneration blastema. In fissioning animals, certain cells on the ventral nerve cord express a homolog of piwi, are abundant near fission zones, and sometimes make contact with gonads. Such cells are typically undetectable near the blastema and posterior growth zone. Time-lapse imaging provides direct evidence that cells on the ventral nerve cord migrate preferentially towards fission zones. Our findings indicate that gonads form routinely in fissioning individuals, that a population of piwi-positive cells on the ventral nerve cord is associated with fission and gonads, and that cells resembling these piwi-positive cells migrate along the ventral nerve cord. We suggest that the piwi-positive ventral cells are germ cells that transmit the germ line across asexually produced individuals via migration along the ventral nerve cord. Copyright © 2015 Elsevier Inc. All rights reserved.

The ethics of germ line gene manipulation--a five dimensional debate.

PubMed

Carter, Lucy

2002-10-01

Contributors to the debate surrounding the ethics of germ line gene manipulation have by and large concentrated their efforts on discussions of the potential risks that are associated with the use of this technology. Many international advisory committees have ruled out the acceptability of germ line gene manipulation at least for the time being. The purpose of this work is to generate much needed discussion on the many other ethical issues concerning the implementation of not only germ line gene manipulation but also other related biotechnologies. In this paper I systematically investigate and analyse the most salient issues put forward by proponents and opponents alike. I argue that if germ line manipulation proves to be a safe and effective procedure, then the principle of beneficence imposes on the medical profession a moral duty to pursue the technology.

THE DEVELOPMENT OF SEXUAL DIMORPHISM: STUDIES OF THE C. ELEGANS MALE

PubMed Central

Emmons, Scott W.

2014-01-01

Studies of the development of the C. elegans male have been carried out with the aim of understanding the basis of sexual dimorphism. Postembryonic development of the two C. elegans sexes differs extensively. Development along either the hermaphrodite or male pathway is specified initially by the X to autosome ratio. The regulatory events initiated by this ratio include a male-determining paracrine intercellular signal. Expression of this signal leads to different consequences in three regions of the body: the non-gonadal soma, the somatic parts of the gonad, and the germ line. In the non-gonadal soma, activity of the key Zn-finger transcription factor TRA 1 determines hermaphrodite development; in its absence, the male pathway is followed. Only a few genes directly regulated by TRA 1 are currently known, including members of the evolutionarily conserved, male-determining DM domain Zn-finger transcription factors. In the somatic parts of the gonad and germ line, absence of TRA 1 activity is not sufficient for full expression of the male pathway. Several additional transcription factors involved have been identified. In the germ line, regulatory genes for sperm development that act at the level of RNA in the cytoplasm play a prominent role. PMID:25262817

Germ line transmission of a yeast artificial chromosome spanning the murine [alpha][sub 1](I) collagen locus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strauss, W.M.; Dausman, J.; Beard, C.

Molecular complementation of mutant phenotypes by transgenic technology is a potentially important tool for gene identification. A technology was developed to allow the transfer of a physically intact yeast artificial chromosome (YAC) into the germ line of the mouse. A purified 150-kilobase YAC encompassing the murine gene Col1a1 was efficiently introduced into embryonic stem (ES) cells via lipofection. Chimeric founder mice were derived from two transfected ES cell clones. These chimeras transmitted the full length transgene through the germ line, generating two transgenic mouse strains. Transgene expression was visualized as nascent transcripts in interphase nuclei and quantitated by ribonuclease protectionmore » analysis. Both assays indicated that the transgene was expressed at levels comparable to the endogenous collagen gene. 32 refs., 3 figs., 1 tab.« less

An extreme bias in the germ line of XY C57BL/6<->XY FVB/N chimaeric mice

PubMed Central

MacGregor, G. R.

2011-01-01

Chimaeric analysis is a powerful method to address questions about the cell-autonomous nature of defects in spermatogenesis. Symplastic spermatids (sys) mice have a recessive mutation that causes male sterility due to an arrest in germ-cell development during spermiogenesis. Chimaeric mice were generated by aggregation of eight-cell embryos from sys (FVB/N genetic background) and wild-type C57BL/6 (B6) mice to determine whether the male germ-cell defect is cell-autonomous. The resulting FVB/N<->B6 chimaeras (<-> denotes fusion of embryos) were mated with FVB/N mice and coat colour of offspring was used to identify transmission of FVB/N or B6 gametes. Regardless of the relative contribution of B6 to somatic tissues of the chimaeras, almost all (282 of 284; 99.3%) offspring of B6 XY<->XY FVB/N (+/+ or sys/+) males (n = 9) received a FVB/N-derived paternal gamete. After mating of female B6<->FVB/N chimaeras, 51 of 73 (69.9%) offspring received an FVB-derived maternal gamete. Southern blot analysis of different tissues from chimaeric males indicated that, despite the presence of balanced chimaerism in somatic tissues, the germ line in B6 XY<->XY FVB/N mice was essentially FVB/N in composition. Thus there is a strong selective advantage for FVB/N male germ cells over B6 male germ cells in B6<->FVB/N-aggregation chimaeras at some stage during development of the male germ line. Each of three male chimaeras that were either B6 XY<->XY FVB/N (sys/sys) or B6 XX<->XY FVB/N (sys/sys) in composition was sterile, and testis histology was essentially sys mutant. This finding indicates that the function of the gene(s) affected in the sys mutation may be required in the testis, although whether expression is required in germ cells, somatic cells or both remains unknown. The extreme bias in transmission of male gametes has implications for experimental design in studies that use chimaeric analysis to address questions regarding the cell-autonomous nature of germ-cell defects in mice. PMID:12201811

Co-existence of breast and ovarian cancers in BRCA germ-line mutation carriers

PubMed Central

Dilawari, A; Cangiarella, J; Smith, J; Huang, A; Downey, A; Muggia, F

2008-01-01

The co-existence of breast and ovarian cancers in the same individual should raise suspicion of a hereditary process. Patients with either BRCA1 or BRCA2 germ-line mutations have an average risk of 39% and 11% respectively of developing ovarian cancer by the age of 70; they have a risk of 35–85% of developing breast cancer in their lifetime. We report here unusual pathologic features in a BRCA2 germ-line mutation carrier recently diagnosed with synchronous breast and ovarian cancers, and summarize the findings in six other women who were diagnosed with ovarian cancer either simultaneously with the diagnosis of breast cancer or at varying times after the diagnosis. While in most instances this may be a coincidental occurrence in highly susceptible individuals, the patient we highlight raises the provocative hypothesis that at times breast cancer metastasizes to the ovaries of mutation carriers and stimulates the development of an ovarian cancer as well as other cancers. In addition, these ovarian cancers may have different mechanisms of metastases predisposing them to travel to unusual sites. PMID:22275985

Autosomal Genes of Autosomal/X-Linked Duplicated Gene Pairs and Germ-Line Proliferation in Caenorhabditis elegans

PubMed Central

Maciejowski, John; Ahn, James Hyungsoo; Cipriani, Patricia Giselle; Killian, Darrell J.; Chaudhary, Aisha L.; Lee, Ji Inn; Voutev, Roumen; Johnsen, Robert C.; Baillie, David L.; Gunsalus, Kristin C.; Fitch, David H. A.; Hubbard, E. Jane Albert

2005-01-01

We report molecular genetic studies of three genes involved in early germ-line proliferation in Caenorhabditis elegans that lend unexpected insight into a germ-line/soma functional separation of autosomal/X-linked duplicated gene pairs. In a genetic screen for germ-line proliferation-defective mutants, we identified mutations in rpl-11.1 (L11 protein of the large ribosomal subunit), pab-1 [a poly(A)-binding protein], and glp-3/eft-3 (an elongation factor 1-α homolog). All three are members of autosome/X gene pairs. Consistent with a germ-line-restricted function of rpl-11.1 and pab-1, mutations in these genes extend life span and cause gigantism. We further examined the RNAi phenotypes of the three sets of rpl genes (rpl-11, rpl-24, and rpl-25) and found that for the two rpl genes with autosomal/X-linked pairs (rpl-11 and rpl-25), zygotic germ-line function is carried by the autosomal copy. Available RNAi results for highly conserved autosomal/X-linked gene pairs suggest that other duplicated genes may follow a similar trend. The three rpl and the pab-1/2 duplications predate the divergence between C. elegans and C. briggsae, while the eft-3/4 duplication appears to have occurred in the lineage to C. elegans after it diverged from C. briggsae. The duplicated C. briggsae orthologs of the three C. elegans autosomal/X-linked gene pairs also display functional differences between paralogs. We present hypotheses for evolutionary mechanisms that may underlie germ-line/soma subfunctionalization of duplicated genes, taking into account the role of X chromosome silencing in the germ line and analogous mammalian phenomena. PMID:15687263

TAp73 is essential for germ cell adhesion and maturation in testis

PubMed Central

Holembowski, Lena; Kramer, Daniela; Riedel, Dietmar; Sordella, Raffaella; Nemajerova, Alice; Dobbelstein, Matthias

2014-01-01

A core evolutionary function of the p53 family is to protect the genomic integrity of gametes. However, the role of p73 in the male germ line is unknown. Here, we reveal that TAp73 unexpectedly functions as an adhesion and maturation factor of the seminiferous epithelium orchestrating spermiogenesis. TAp73 knockout (TAp73KO) and p73KO mice, but not ΔNp73KO mice, display a “near-empty seminiferous tubule” phenotype due to massive premature loss of immature germ cells. The cellular basis of this phenotype is defective cell–cell adhesions of developing germ cells to Sertoli nurse cells, with likely secondary degeneration of Sertoli cells, including the blood–testis barrier, which leads to disruption of the adhesive integrity and maturation of the germ epithelium. At the molecular level, TAp73, which is produced in germ cells, controls a coordinated transcriptional program of adhesion- and migration-related proteins including peptidase inhibitors, proteases, receptors, and integrins required for germ–Sertoli cell adhesion and dynamic junctional restructuring. Thus, we propose the testis as a unique organ with strict division of labor among all family members: p63 and p53 safeguard germ line fidelity, whereas TAp73 ensures fertility by enabling sperm maturation. PMID:24662569

Convergent evolution of germ granule nucleators: A hypothesis.

PubMed

Kulkarni, Arpita; Extavour, Cassandra G

2017-10-01

Germ cells have been considered "the ultimate stem cell" because they alone, during normal development of sexually reproducing organisms, are able to give rise to all organismal cell types. Morphological descriptions of a specialized cytoplasm termed 'germ plasm' and associated electron dense ribonucleoprotein (RNP) structures called 'germ granules' within germ cells date back as early as the 1800s. Both germ plasm and germ granules are implicated in germ line specification across metazoans. However, at a molecular level, little is currently understood about the molecular mechanisms that assemble these entities in germ cells. The discovery that in some animals, the gene products of a small number of lineage-specific genes initiate the assembly (also termed nucleation) of germ granules and/or germ plasm is the first step towards facilitating a better understanding of these complex biological processes. Here, we draw on research spanning over 100years that supports the hypothesis that these nucleator genes may have evolved convergently, allowing them to perform analogous roles across animal lineages. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Chick stem cells: Current progress and future prospects

PubMed Central

Intarapat, Sittipon; Stern, Claudio D.

2013-01-01

Chick embryonic stem cells (cESCs) can be derived from cells obtained from stage X embryos (blastoderm stage); these have the ability to contribute to all somatic lineages in chimaeras, but not to the germ line. However, lines of stem cells that are able to contribute to the germ line can be established from chick primordial germ cells (cPGCs) and embryonic germ cells (cEGCs). This review provides information on avian stem cells, emphasizing different sources of cells and current methods for derivation and culture of pluripotent cells from chick embryos. We also review technologies for isolation and derivation of chicken germ cells and the production of transgenic birds. PMID:24103496

PIE-1 is a bifunctional protein that regulates maternal and zygotic gene expression in the embryonic germ line of Caenorhabditis elegans

PubMed Central

Tenenhaus, Christina; Subramaniam, Kuppuswamy; Dunn, Melanie A.; Seydoux, Geraldine

2001-01-01

The CCCH zinc finger protein PIE-1 is an essential regulator of germ cell fate that segregates with the germ lineage during the first cleavages of the Caenorhabditis elegans embryo. We have shown previously that one function of PIE-1 is to inhibit mRNA transcription. Here we show that PIE-1 has a second function in germ cells; it is required for efficient expression of the maternally encoded Nanos homolog NOS-2. This second function is genetically separable from PIE-1's inhibitory effect on transcription. A mutation in PIE-1's second CCCH finger reduces NOS-2 expression without affecting transcriptional repression and causes primordial germ cells to stray away from the somatic gonad, occasionally exiting the embryo entirely. Our results indicate that PIE-1 promotes germ cell fate by two independent mechanisms as follows: (1) inhibition of transcription, which blocks zygotic programs that drive somatic development, and (2) activation of protein expression from nos-2 and possibly other maternal RNAs, which promotes primordial germ cell development. PMID:11316796

Avian germplasm preservation: embryonic stem cells or primordial germ cells?

PubMed

Petitte, J N

2006-02-01

Presently, avian genetic resources are best maintained as living collections of birds. Unfortunately, these stocks have been under constant pressure to be destroyed because of the decline in the number of Poultry Science Departments and pressures to cut costs at land grant institutions. Cryopreservation of semen is often suggested as a means to bank avian germplasm. However, this is only applicable for single-gene traits and does not allow for full reconstitution of the genetics of the original line. Over the last 15 yr, advances in the manipulation of the early chick embryo, manipulation of primordial germ cells (PGC), and the culture of embryonic stem cells (ESC) suggests that cryopreservation of blastodermal cells, ESC, or PGC might offer a means to preserve the entire genome of highly selected, specialized stocks of poultry. Freezing each of these cell types is possible with varying degrees of efficiency. Similarly, the effectiveness of generating germ line chimeras using blastodermal cells, ESC, or PGC also varies greatly. Other factors that must be considered include the choice of the recipient lines to develop the germ line chimeras and the number of individuals needed to reconstitute the line. Finally, the low efficiency rate of reconstitution and the high cost associated with current technologies makes these approaches prohibitive. Significant challenges remain to be overcome before the entire genome of poultry stocks can be routinely cryoperserved and reconstituted.

Zebrafish Staufen1 and Staufen2 are required for the survival and migration of primordial germ cells.

PubMed

Ramasamy, Srinivas; Wang, Hui; Quach, Helen Ngoc Bao; Sampath, Karuna

2006-04-15

In sexually reproducing organisms, primordial germ cells (PGCs) give rise to the cells of the germ line, the gametes. In many animals, PGCs are set apart from somatic cells early during embryogenesis. Work in Drosophila, C. elegans, Xenopus, and zebrafish has shown that maternally provided localized cytoplasmic determinants specify the germ line in these organisms (Raz, E., 2003. Primordial germ-cell development: the zebrafish perspective. Nat. Rev., Genet. 4, 690--700; Santos, A.C., Lehmann, R., 2004. Germ cell specification and migration in Drosophila and beyond. Curr. Biol. 14, R578-R589). The Drosophila RNA-binding protein, Staufen is required for germ cell formation, and mutations in stau result in a maternal effect grandchild-less phenotype (Schupbach,T., Weischaus, E., 1989. Female sterile mutations on the second chromosome of Drosophila melanogaster:1. Maternal effect mutations. Genetics 121, 101-17). Here we describe the functions of two zebrafish Staufen-related proteins, Stau1 and Stau2. When Stau1 or Stau2 functions are compromised in embryos by injecting antisense morpholino modified oligonucleotides or dominant-negative Stau peptides, germ layer patterning is not affected. However, expression of the PGC marker vasa is not maintained. Furthermore, expression of a green fluorescent protein (GFP):nanos 3'UTR fusion protein in germ cells shows that PGC migration is aberrant, and the mis-migrating PGCs do not survive in Stau-compromised embryos. Stau2 is also required for survival of neurons in the central nervous system (CNS). These phenotypes are rescued by co-injection of Drosophila stau mRNA. Thus, staufen has an evolutionarily conserved function in germ cells. In addition, we have identified a function for Stau proteins in PGC migration.

FGF9, activin and TGFβ promote testicular characteristics in an XX gonad organ culture model.

PubMed

Gustin, Sonja E; Stringer, Jessica M; Hogg, Kirsten; Sinclair, Andrew H; Western, Patrick S

2016-11-01

Testis development is dependent on the key sex-determining factors SRY and SOX9, which activate the essential ligand FGF9. Although FGF9 plays a central role in testis development, it is unable to induce testis formation on its own. However, other growth factors, including activins and TGFβs, also present testis during testis formation. In this study, we investigated the potential of FGF9 combined with activin and TGFβ to induce testis development in cultured XX gonads. Our data demonstrated differing individual and combined abilities of FGF9, activin and TGFβ to promote supporting cell proliferation, Sertoli cell development and male germ line differentiation in cultured XX gonads. FGF9 promoted proliferation of supporting cells in XX foetal gonads at rates similar to those observed in vivo during testis cord formation in XY gonads but was insufficient to initiate testis development. However, when FGF9, activin and TGFβ were combined, aspects of testicular development were induced, including the expression of Sox9, morphological reorganisation of the gonad and deposition of laminin around germ cells. Enhancing β-catenin activity diminished the testis-promoting activities of the combined growth factors. The male promoting activity of FGF9 and the combined growth factors directly or indirectly extended to the germ line, in which a mixed phenotype was observed. FGF9 and the combined growth factors promoted male germ line development, including mitotic arrest, but expression of pluripotency genes was maintained, rather than being repressed. Together, our data provide evidence that combined signalling by FGF9, activin and TGFβ can induce testicular characteristics in XX gonads. © 2016 Society for Reproduction and Fertility.

Epigenetic Transgenerational Actions of Vinclozolin on the Development of Disease and Cancer

PubMed Central

Skinner, Michael K.; Anway, Matthew D.

2018-01-01

Exposure to an environmental endocrine disruptor (e.g., vinclozolin) during embryonic gonadal sex determination appears to alter the male germ line epigenome and subsequently promotes transgenerational adult onset disease. The epigenetic mechanism involves the induction of new imprinted-like genes/DNA sequences in the germ line that appear to transmit disease phenotypes. The disease phenotypes include testis abnormalities, prostate disease, kidney disease, immune abnormalities, and tumor development. This epigenetic transgenerational disease mechanism provides a unique perspective from which to view inheritable adult onset disease states, such as cancer, and ultimately offers new insights into novel diagnostic and therapeutic strategies. PMID:17956218

X Chromosome Crossover Formation and Genome Stability in Caenorhabditis elegans Are Independently Regulated by xnd-1

PubMed Central

McClendon, T. Brooke; Mainpal, Rana; Amrit, Francis R. G.; Krause, Michael W.; Ghazi, Arjumand; Yanowitz, Judith L.

2016-01-01

The germ line efficiently combats numerous genotoxic insults to ensure the high fidelity propagation of unaltered genomic information across generations. Yet, germ cells in most metazoans also intentionally create double-strand breaks (DSBs) to promote DNA exchange between parental chromosomes, a process known as crossing over. Homologous recombination is employed in the repair of both genotoxic lesions and programmed DSBs, and many of the core DNA repair proteins function in both processes. In addition, DNA repair efficiency and crossover (CO) distribution are both influenced by local and global differences in chromatin structure, yet the interplay between chromatin structure, genome integrity, and meiotic fidelity is still poorly understood. We have used the xnd-1 mutant of Caenorhabditis elegans to explore the relationship between genome integrity and crossover formation. Known for its role in ensuring X chromosome CO formation and germ line development, we show that xnd-1 also regulates genome stability. xnd-1 mutants exhibited a mortal germ line, high embryonic lethality, high incidence of males, and sensitivity to ionizing radiation. We discovered that a hypomorphic allele of mys-1 suppressed these genome instability phenotypes of xnd-1, but did not suppress the CO defects, suggesting it serves as a separation-of-function allele. mys-1 encodes a histone acetyltransferase, whose homolog Tip60 acetylates H2AK5, a histone mark associated with transcriptional activation that is increased in xnd-1 mutant germ lines, raising the possibility that thresholds of H2AK5ac may differentially influence distinct germ line repair events. We also show that xnd-1 regulated him-5 transcriptionally, independently of mys-1, and that ectopic expression of him-5 suppressed the CO defects of xnd-1. Our work provides xnd-1 as a model in which to study the link between chromatin factors, gene expression, and genome stability. PMID:27678523

Spontaneous pregnancy in a woman with 45,X/47,XXX mosaicism in both serum and germ cell lines. A case report.

PubMed

Eblen, Abby C; Nakajima, Steve T

2003-02-01

This is the first published case report of pregnancy in a women with 45, X/47, XXX mosaicism in both blood and germ cell lines. The patient conceived, and analysis of ovarian tissue confirmed a karyotype of 45, X/47, XXX. Women with a 45, X/47, XXX karyotype in the germ cell line can conceive, as this case demonstrates.

Human somatic cells subjected to genetic induction with six germ line-related factors display meiotic germ cell-like features

PubMed Central

Medrano, Jose V.; Martínez-Arroyo, Ana M.; Míguez, Jose M.; Moreno, Inmaculada; Martínez, Sebastián; Quiñonero, Alicia; Díaz-Gimeno, Patricia; Marqués-Marí, Ana I.; Pellicer, Antonio; Remohí, Jose; Simón, Carlos

2016-01-01

The in vitro derivation of human germ cells has attracted interest in the last years, but their direct conversion from human somatic cells has not yet been reported. Here we tested the ability of human male somatic cells to directly convert into a meiotic germ cell-like phenotype by inducing them with a combination of selected key germ cell developmental factors. We started with a pool of 12 candidates that were reduced to 6, demonstrating that ectopic expression of the germ line-related genes PRDM1, PRDM14, LIN28A, DAZL, VASA and SYCP3 induced direct conversion of somatic cells (hFSK (46, XY), and hMSC (46, XY)) into a germ cell-like phenotype in vitro. Induced germ cell-like cells showed a marked switch in their transcriptomic profile and expressed several post-meiotic germ line related markers, showed meiotic progression, evidence of epigenetic reprogramming, and approximately 1% were able to complete meiosis as demonstrated by their haploid status and the expression of several post-meiotic markers. Furthermore, xenotransplantation assays demonstrated that a subset of induced cells properly colonize the spermatogonial niche. Knowledge obtained from this work can be used to create in vitro models to study gamete-related diseases in humans. PMID:27112843

Cell adhesion molecules expression pattern indicates that somatic cells arbitrate gonadal sex of differentiating bipotential fetal mouse gonad.

PubMed

Piprek, Rafal P; Kolasa, Michal; Podkowa, Dagmara; Kloc, Malgorzata; Kubiak, Jacek Z

2017-10-01

Unlike other organ anlagens, the primordial gonad is sexually bipotential in all animals. In mouse, the bipotential gonad differentiates into testis or ovary depending on the genetic sex (XY or XX) of the fetus. During gonad development cells segregate, depending on genetic sex, into distinct compartments: testis cords and interstitium form in XY gonad, and germ cell cysts and stroma in XX gonad. However, our knowledge of mechanisms governing gonadal sex differentiation remains very vague. Because it is known that adhesion molecules (CAMs) play a key role in organogenesis, we suspected that diversified expression of CAMs should also play a crucial role in gonad development. Using microarray analysis we identified 129 CAMs and factors regulating cell adhesion during sexual differentiation of mouse gonad. To identify genes expressed differentially in three cell lines in XY and XX gonads: i) supporting (Sertoli or follicular cells), ii) interstitial or stromal cells, and iii) germ cells, we used transgenic mice expressing EGFP reporter gene and FACS cell sorting. Although a large number of CAMs expressed ubiquitously, expression of certain genes was cell line- and genetic sex-specific. The sets of CAMs differentially expressed in supporting versus interstitial/stromal cells may be responsible for segregation of these two cell lines during gonadal development. There was also a significant difference in CAMs expression pattern between XY supporting (Sertoli) and XX supporting (follicular) cells but not between XY and XX germ cells. This indicates that differential CAMs expression pattern in the somatic cells but not in the germ line arbitrates structural organization of gonadal anlagen into testis or ovary. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of chemical and physical agents on recombination events in cells of the germ line of male and female Drosophila melanogaster.

PubMed

Würgler, F E

1991-01-01

Genotoxic agents can induce mutations as well as recombination in the genetic material. The fruit fly Drosophila melanogaster was one of the first assay systems to test physical and chemical agents for recombinogenic effects. Such effects can be observed in cells of the germ line as well as in somatic cells. At present information is available on 54 agents, among them 48 chemicals that have been tested in cells of the germ line of males and/or females. Effects on meiotic recombination in female germ cells cannot simply be classified as positive or negative since for a number of agents, depending on the chromosome region studied, recombination frequencies may be increased, unaffected or decreased. The male germ line of D. melanogaster represents a unique situation because meiotic recombination does not occur. Among 25 agents tested in male germ cells 24 did induce male recombination, among them alkylating, intercalating and cross-linking agents, direct-acting ones as well as compounds needing metabolic activation. With several compounds the frequency of induced recombination is highest in the heterochromatic regions near the centromeres. In brood pattern analyses, e.g., after exposure of adult males to ionizing radiation, the first appearance of crossover progeny is indicative of the sampling of exposed spermatocytes. In premeiotic cells of the male and the female germ line mitotic recombination can occur. Upon clonal expansion of the recombinant cells, clusters of identical crossovers can be observed.

Rhabdoid tumor predisposition syndrome caused by SMARCB1 constitutional deletion: prenatal detection of new case of recurrence in siblings due to gonadal mosaicism.

PubMed

Gigante, Laura; Paganini, Irene; Frontali, Marina; Ciabattoni, Serena; Sangiuolo, Federica Carla; Papi, Laura

2016-01-01

Rhabdoid tumors are aggressive malignancies that show loss-of-function mutations of SMARCB1 gene, a member of the SWI/SNF chromatin-remodeling complex controlling gene transcription. One-third of patients affected by rhabdoid tumor harbor a germ-line mutation of SMARCB1 defining a rhabdoid tumor predisposition syndrome. The occurrence of a second somatic mutation determines the development of neoplasia in a two-hit model. Most germ-line mutations occur de novo, and few cases of recurrence in a sibship have been described. Here we report on a new Italian family with recurrence of SMARCB1 germ-line deletion in two siblings due to gonadal mosaicism. The deletion was identified in the 9-month-old proband with malignant rhabdoid tumor of the right kidney and disseminated metastases. Testing of both parents confirmed the de novo origin of the mutation, but recurrence was then detected prenatally in a new pregnancy. This is the sixth family with malignant rhabdoid tumor predisposition syndrome with the recurrence of the same germ-line SMARCB1 mutation in the sibship but not in healthy parents, suggesting that gonadal mosaicism is a less rare event than supposed. The clinical outcome in our patient confirms previous data of poorer outcome in patients with rhabdoid tumor predisposition syndrome.

Beyond the Mouse Monopoly: Studying the Male Germ Line in Domestic Animal Models

PubMed Central

González, Raquel; Dobrinski, Ina

2015-01-01

Spermatogonial stem cells (SSCs) are the foundation of spermatogenesis and essential to maintain the continuous production of spermatozoa after the onset of puberty in the male. The study of the male germ line is important for understanding the process of spermatogenesis, unravelling mechanisms of stemness maintenance, cell differentiation, and cell-to-cell interactions. The transplantation of SSCs can contribute to the preservation of the genome of valuable individuals in assisted reproduction programs. In addition to the importance of SSCs for male fertility, their study has recently stimulated interest in the generation of genetically modified animals because manipulations of the male germ line at the SSC stage will be maintained in the long term and transmitted to the offspring. Studies performed mainly in the mouse model have laid the groundwork for facilitating advancements in the field of male germ line biology, but more progress is needed in nonrodent species in order to translate the technology to the agricultural and biomedical fields. The lack of reliable markers for isolating germ cells from testicular somatic cells and the lack of knowledge of the requirements for germ cell maintenance have precluded their long-term maintenance in domestic animals. Nevertheless, some progress has been made. In this review, we will focus on the state of the art in the isolation, characterization, culture, and manipulation of SSCs and the use of germ cell transplantation in domestic animals. PMID:25991701

Elevated mutation rates in the germ line of first- and second-generation offspring of irradiated male mice

PubMed Central

Barber, Ruth; Plumb, Mark A.; Boulton, Emma; Roux, Isabelle; Dubrova, Yuri E.

2002-01-01

Mutation rates at two expanded simple tandem repeat loci were studied in the germ line of first- and second-generation offspring of inbred male CBA/H, C57BL/6, and BALB/c mice exposed to either high linear energy transfer fission neutrons or low linear energy transfer x-rays. Paternal CBA/H exposure to either x-rays or fission neutrons resulted in increased mutation rates in the germ line of two subsequent generations. Comparable transgenerational effects were observed also in neutron-irradiated C57BL/6 and x-irradiated BALB/c mice. The levels of spontaneous mutation rates and radiation-induced transgenerational instability varied between strains (BALB/c>CBA/H>C57BL/6). Pre- and postmeiotic paternal exposure resulted in similar increases in mutation rate in the germ line of both generations of CBA/H mice, which together with our previous results suggests that radiation-induced expanded simple tandem repeat instability is manifested in diploid cells after fertilization. The remarkable finding that radiation-induced germ-line instability persists for at least two generations raises important issues of risk evaluation in humans. PMID:11997464

DNA Methylation Errors in Cloned Mouse Sperm by Germ Line Barrier Evasion.

PubMed

Koike, Tasuku; Wakai, Takuya; Jincho, Yuko; Sakashita, Akihiko; Kobayashi, Hisato; Mizutani, Eiji; Wakayama, Sayaka; Miura, Fumihito; Ito, Takashi; Kono, Tomohiro

2016-06-01

The germ line reprogramming barrier resets parental epigenetic modifications according to sex, conferring totipotency to mammalian embryos upon fertilization. However, it is not known whether epigenetic errors are committed during germ line reprogramming that are then transmitted to germ cells, and consequently to offspring. We addressed this question in the present study by performing a genome-wide DNA methylation analysis using a target postbisulfite sequencing method in order to identify DNA methylation errors in cloned mouse sperm. The sperm genomes of two somatic cell-cloned mice (CL1 and CL7) contained significantly higher numbers of differentially methylated CpG sites (P = 0.0045 and P = 0.0116). As a result, they had higher numbers of differentially methylated CpG islands. However, there was no evidence that these sites were transmitted to the sperm genome of offspring. These results suggest that DNA methylation errors resulting from embryo cloning are transmitted to the sperm genome by evading the germ line reprogramming barrier. © 2016 by the Society for the Study of Reproduction, Inc.

Germ cell differentiation and proliferation in the developing testis of the South American plains viscacha, Lagostomus maximus (Mammalia, Rodentia).

PubMed

Gonzalez, C R; Muscarsel Isla, M L; Fraunhoffer, N A; Leopardo, N P; Vitullo, A D

2012-08-01

Cell proliferation and cell death are essential processes in the physiology of the developing testis that strongly influence the normal adult spermatogenesis. We analysed in this study the morphometry, the expression of the proliferation cell nuclear antigen (PCNA), cell pluripotency marker OCT-4, germ cell marker VASA and apoptosis in the developing testes of Lagostomus maximus, a rodent in which female germ line develops through abolished apoptosis and unrestricted proliferation. Morphometry revealed an increment in the size of the seminiferous cords with increasing developmental age, arising from a significant increase of PCNA-positive germ cells and a stable proportion of PCNA-positive Sertoli cells. VASA showed a widespread cytoplasmic distribution in a great proportion of proliferating gonocytes that increased significantly at late development. In the somatic compartment, Leydig cells increased at mid-development, whereas peritubular cells showed a stable rate of proliferation. In contrast to other mammals, OCT-4 positive gonocytes increased throughout development reaching 90% of germ cells in late-developing testis, associated with a conspicuous increase in circulating FSH from mid- to late-gestation. TUNEL analysis was remarkable negative, and only a few positive cells were detected in the somatic compartment. These results show that the South American plains viscacha displays a distinctive pattern of testis development characterized by a sustained proliferation of germ cells throughout development, with no signs of apoptosis cell demise, in a peculiar endocrine in utero ambiance that seems to promote the increase of spermatogonial number as a primary direct effect of FSH.

Reprogramming primordial germ cells (PGC) to embryonic germ (EG) cells.

PubMed

Durcova-Hills, Gabriela; Surani, Azim

2008-04-01

In this unit we describe the derivation of pluripotent embryonic germ (EG) cells from mouse primordial germ cells (PGCs) isolated from both 8.5- and 11.5-days post-coitum (dpc) embryos. Once EG cells are derived we explain how to propagate and characterize the cell lines. We introduce readers to PGCs and explain differences between PGCs and their in vitro derivatives EG cells. Finally, we also compare mouse EG cells with ES cells. This unit will be of great interest to anyone interested in PGCs or studying the behavior of cultured PGCs or the derivation of new EG cell lines.

Purpose and regulation of stem cells: a systems-biology view from the Caenorhabditis elegans germ line.

PubMed

Cinquin, Olivier

2009-01-01

Stem cells are expected to play a key role in the development and maintenance of organisms, and hold great therapeutic promises. However, a number of questions must be answered to achieve an understanding of stem cells and put them to use. Here I review some of these questions, and how they relate to the model system provided by the Caenorhabditis elegans germ line, which is exceptional in its thorough genetic characterization and experimental accessibility under in vivo conditions. A fundamental question is how to define a stem cell; different definitions can be adopted that capture different features of interest. In the C. elegans germ line, stem cells can be defined by cell lineage or by cell commitment ('commitment' must itself be carefully defined). These definitions are associated with two other important questions about stem cells: their functions (which must be addressed following a systems approach, based on an evolutionary perspective) and their regulation. I review possible functions and their evolutionary groundings, including genome maintenance and powerful regulation of cell proliferation and differentiation, and possible regulatory mechanisms, including asymmetrical division and control of transit amplification by a developmental timer. I draw parallels between Drosophila and C. elegans germline stem cells; such parallels raise intriguing questions about Drosophila stem cells. I conclude by showing that the C. elegans germ line bears similarities with a number of other stem cell systems, which underscores its relevance to the understanding of stem cells.

GERM-LINE SPECIFIC FACTORS IN CHEMICAL MUTAGENESIS

EPA Science Inventory

Chemical mutagenesis test results ave not revealed evidence of germ-line specific mutagens. owever, conventional assays have indicated that there are male-female differences in mutagenic response, as well as quantitative/qualitative differences in induced mutations which depend u...

Evolution of predetermined germ cells in vertebrate embryos: implications for macroevolution.

PubMed

Johnson, Andrew D; Drum, Matthew; Bachvarova, Rosemary F; Masi, Thomas; White, Mary E; Crother, Brian I

2003-01-01

The germ line is established in animal embryos with the formation of primordial germ cells (PGCs), which give rise to gametes. Therefore, the need to form PGCs can act as a developmental constraint by inhibiting the evolution of embryonic patterning mechanisms that compromise their development. Conversely, events that stabilize the PGCs may liberate these constraints. Two modes of germ cell determination exist in animal embryos: (a) either PGCs are predetermined by the inheritance of germ cell determinants (germ plasm) or (b) PGCs are formed by inducing signals secreted by embryonic tissues (i.e., regulative determination). Surprisingly, among the major extant amphibian lineages, one mechanism is found in urodeles and the other in anurans. In anuran amphibians PGCs are predetermined by germ plasm; in urodele amphibians PGCs are formed by inducing signals. To determine which mechanism is ancestral to the tetrapod lineage and to understand the pattern of inheritance in higher vertebrates, we used a phylogenetic approach to analyze basic morphological processes in both groups and correlated these with mechanisms of germ cell determination. Our results indicate that regulative germ cell determination is a property of embryos retaining ancestral embryological processes, whereas predetermined germ cells are found in embryos with derived morphological traits. These correlations suggest that regulative germ cell formation is an important developmental constraint in vertebrate embryos, acting before the highly conserved pharyngula stage. Moreover, our analysis suggests that germ plasm has evolved independently in several lineages of vertebrate embryos.

Differentiation as symbiosis.

PubMed

Chigira, M; Watanabe, H

1994-07-01

Preservation of the identity of DNA is the ultimate goal of multicellular organisms. An abnormal DNA sequence in cells within an individual means its parasitic nature in cell society as shown in tumors. Somatic gene arrangement and gene mutation in development may be considered as de novo formation of parasites. It is likely that the developmental process with genetic alterations means symbiosis between altered cells and germ line cells preserving genetic information without alterations, when somatic alteration of DNA sequence is a major mechanism of differentiation. According to the selfish gene theory of Dawkins, germ line cells permit symbiosis when somatic cell society derives clear profit for the replication of original DNA copies.

Germ line p53 mutations in a familial syndrome of breast cancer, sarcomas, and other neoplasms.

PubMed

Malkin, D; Li, F P; Strong, L C; Fraumeni, J F; Nelson, C E; Kim, D H; Kassel, J; Gryka, M A; Bischoff, F Z; Tainsky, M A

1990-11-30

Familial cancer syndromes have helped to define the role of tumor suppressor genes in the development of cancer. The dominantly inherited Li-Fraumeni syndrome (LFS) is of particular interest because of the diversity of childhood and adult tumors that occur in affected individuals. The rarity and high mortality of LFS precluded formal linkage analysis. The alternative approach was to select the most plausible candidate gene. The tumor suppressor gene, p53, was studied because of previous indications that this gene is inactivated in the sporadic (nonfamilial) forms of most cancers that are associated with LFS. Germ line p53 mutations have been detected in all five LFS families analyzed. These mutations do not produce amounts of mutant p53 protein expected to exert a trans-dominant loss of function effect on wild-type p53 protein. The frequency of germ line p53 mutations can now be examined in additional families with LFS, and in other cancer patients and families with clinical features that might be attributed to the mutation.

Preventing the transmission of pathogenic mitochondrial DNA mutations: Can we achieve long-term benefits from germ-line gene transfer?

PubMed

Samuels, David C; Wonnapinij, Passorn; Chinnery, Patrick F

2013-03-01

Mitochondrial medicine is one of the few areas of genetic disease where germ-line transfer is being actively pursued as a treatment option. All of the germ-line transfer methods currently under development involve some carry-over of the maternal mitochondrial DNA (mtDNA) heteroplasmy, potentially delivering the pathogenic mutation to the offspring. Rapid changes in mtDNA heteroplasmy have been observed within a single generation, and so any 'leakage' of mutant mtDNA could lead to mtDNA disease in future generations, compromising the reproductive health of the first generation, and leading to repeated interventions in subsequent generations. To determine whether this is a real concern, we developed a model of mtDNA heteroplasmy inheritance by studying 87 mother-child pairs, and predicted the likely outcome of different levels of 'mutant mtDNA leakage' on subsequent maternal generations. This showed that, for a clinical threshold of 60%, reducing the proportion of mutant mtDNA to <5% dramatically reduces the chance of disease recurrence in subsequent generations, but transmitting >5% mutant mtDNA was associated with a significant chance of disease recurrence. Mutations with a lower clinical threshold were associated with a higher risk of recurrence. Our findings provide reassurance that, at least from an mtDNA perspective, methods currently under development have the potential to effectively eradicate pathogenic mtDNA mutations from subsequent generations.

Primary Culture System for Germ Cells from Caenorhabditis elegans Tumorous Germline Mutants

PubMed Central

Vagasi, Alexandra S.; Rahman, Mohammad M.; Chaudhari, Snehal N.; Kipreos, Edward T.

2017-01-01

The Caenorhabditis elegans germ line is an important model system for the study of germ stem cells. Wild-type C. elegans germ cells are syncytial and therefore cannot be isolated in in vitro cultures. In contrast, the germ cells from tumorous mutants can be fully cellularized and isolated intact from the mutant animals. Here we describe a detailed protocol for the isolation of germ cells from tumorous mutants that allows the germ cells to be maintained for extended periods in an in vitro primary culture. This protocol has been adapted from Chaudhari et al., 2016. PMID:28868332

The Hippo Pathway Regulates Homeostatic Growth of Stem Cell Niche Precursors in the Drosophila Ovary

PubMed Central

Sarikaya, Didem P.; Extavour, Cassandra G.

2015-01-01

The Hippo pathway regulates organ size, stem cell proliferation and tumorigenesis in adult organs. Whether the Hippo pathway influences establishment of stem cell niche size to accommodate changes in organ size, however, has received little attention. Here, we ask whether Hippo signaling influences the number of stem cell niches that are established during development of the Drosophila larval ovary, and whether it interacts with the same or different effector signaling pathways in different cell types. We demonstrate that canonical Hippo signaling regulates autonomous proliferation of the soma, while a novel hippo-independent activity of Yorkie regulates autonomous proliferation of the germ line. Moreover, we demonstrate that Hippo signaling mediates non-autonomous proliferation signals between germ cells and somatic cells, and contributes to maintaining the correct proportion of these niche precursors. Finally, we show that the Hippo pathway interacts with different growth pathways in distinct somatic cell types, and interacts with EGFR and JAK/STAT pathways to regulate non-autonomous proliferation of germ cells. We thus provide evidence for novel roles of the Hippo pathway in establishing the precise balance of soma and germ line, the appropriate number of stem cell niches, and ultimately regulating adult female reproductive capacity. PMID:25643260

Market stimulus and genomic justice: evaluating the effects of market access to human germ-line enhancement.

PubMed

Crozier, G K D; Hajzler, Christopher

2010-06-01

The concept of "market stimulus"--the idea that free markets can play a role in widening access to new technologies--may help support the view that parents should be permitted to purchase germ-line enhancements. However, a critical examination of the topic shows that market stimulus, even if it applies to human genomic interventions, does not provide sufficient reason for deregulating germ-line enhancements because: (1) it could widen the gap between the rich and the poor; (2) even if it does not widen the gap, it might not sufficiently benefit the poor; and (3) it could have harmful effects for future generations.

Epigenetic: a molecular link between testicular cancer and environmental exposures.

PubMed

Vega, Aurelie; Baptissart, Marine; Caira, Françoise; Brugnon, Florence; Lobaccaro, Jean-Marc A; Volle, David H

2012-01-01

In the last decades, studies in rodents have highlighted links between in utero and/or neonatal exposures to molecules that alter endocrine functions and the development of genital tract abnormalities, such as cryptorchidism, hypospadias, and impaired spermatogenesis. Most of these molecules, called endocrine disrupters exert estrogenic and/or antiandrogenic activities. These data led to the hypothesis of the testicular dysgenesis syndrome which postulates that these disorders are one clinical entity and are linked by epidemiological and pathophysiological relations. Furthermore, infertility has been stated as a risk factor for testicular cancer (TC). The incidence of TC has been increasing over the past decade. Most of testicular germ cell cancers develop through a pre-invasive carcinoma in situ from fetal germ cells (primordial germ cell or gonocyte). During their development, fetal germ cells undergo epigenetic modifications. Interestingly, several lines of evidence have shown that gene regulation through epigenetic mechanisms (DNA and histone modifications) plays an important role in normal development as well as in various diseases, including TC. Here we will review chromatin modifications which can affect testicular physiology leading to the development of TC; and highlight potential molecular pathways involved in these alterations in the context of environmental exposures.

Epigenetic: a molecular link between testicular cancer and environmental exposures

PubMed Central

Vega, Aurelie; Baptissart, Marine; Caira, Françoise; Brugnon, Florence; Lobaccaro, Jean-Marc A.; Volle, David H.

2012-01-01

In the last decades, studies in rodents have highlighted links between in utero and/or neonatal exposures to molecules that alter endocrine functions and the development of genital tract abnormalities, such as cryptorchidism, hypospadias, and impaired spermatogenesis. Most of these molecules, called endocrine disrupters exert estrogenic and/or antiandrogenic activities. These data led to the hypothesis of the testicular dysgenesis syndrome which postulates that these disorders are one clinical entity and are linked by epidemiological and pathophysiological relations. Furthermore, infertility has been stated as a risk factor for testicular cancer (TC). The incidence of TC has been increasing over the past decade. Most of testicular germ cell cancers develop through a pre-invasive carcinoma in situ from fetal germ cells (primordial germ cell or gonocyte). During their development, fetal germ cells undergo epigenetic modifications. Interestingly, several lines of evidence have shown that gene regulation through epigenetic mechanisms (DNA and histone modifications) plays an important role in normal development as well as in various diseases, including TC. Here we will review chromatin modifications which can affect testicular physiology leading to the development of TC; and highlight potential molecular pathways involved in these alterations in the context of environmental exposures. PMID:23230429

Characterizing the mechanical behavior of the zebrafish germ layers

NASA Astrophysics Data System (ADS)

Kealhofer, David; Serwane, Friedhelm; Mongera, Alessandro; Rowghanian, Payam; Lucio, Adam; Campàs, Otger

Organ morphogenesis and the development of the animal body plan involve complex spatial and temporal control of tissue- and cell-level mechanics. A prime example is the generation of stresses by individual cells to reorganize the tissue. These processes have remained poorly understood due to a lack of techniques to characterize the local constitutive law of the material, which relates local cellular forces to the resulting tissue flows. We have developed a method for quantitative, local in vivo study of material properties in living tissue using magnetic droplet probes. We use this technique to study the material properties of the different zebrafish germ layers using aggregates of zebrafish mesendodermal and ectodermal cells as a model system. These aggregates are ideal for controlled studies of the mechanics of individual germ layers because of the homogeneity of the cell type and the simple spherical geometry. Furthermore, the numerous molecular tools and transgenic lines already developed for this model organism can be applied to these aggregates, allowing us to characterize the contributions of cell cortex tension and cell adhesion to the mechanical properties of the zebrafish germ layers.

Preventing the transmission of pathogenic mitochondrial DNA mutations: can we achieve long-term benefits from germ-line gene transfer?

PubMed Central

Samuels, David C.; Wonnapinij, Passorn; Chinnery, Patrick F.

2013-01-01

Mitochondrial medicine is one of the few areas of genetic disease where germ-line transfer is being actively pursued as a treatment option. All of the germ-line transfer methods currently under development involve some carry-over of the maternal mitochondrial DNA (mtDNA) heteroplasmy, potentially delivering the pathogenic mutation to the offspring. Rapid changes in mtDNA heteroplasmy have been observed within a single generation, and so any ‘leakage’ of mutant mtDNA could lead to mtDNA disease in future generations, compromising the reproductive health of the first generation, and leading to repeated interventions in subsequent generations. To determine whether this is a real concern, we developed a model of mtDNA heteroplasmy inheritance by studying 87 mother–child pairs, and predicted the likely outcome of different levels of ‘mutant mtDNA leakage’ on subsequent maternal generations. This showed that, for a clinical threshold of 60%, reducing the proportion of mutant mtDNA to <5% dramatically reduces the chance of disease recurrence in subsequent generations, but transmitting >5% mutant mtDNA was associated with a significant chance of disease recurrence. Mutations with a lower clinical threshold were associated with a higher risk of recurrence. Our findings provide reassurance that, at least from an mtDNA perspective, methods currently under development have the potential to effectively eradicate pathogenic mtDNA mutations from subsequent generations. PMID:23297368

Identifying Determinants of PARP Inhibitor Sensitivity in Ovarian Cancer

DTIC Science & Technology

2016-10-01

inhibitors. Ovarian cancer patients that harbored germ- line BRCA1 mutations treated with PARP inhibitors exhibited meaningful responses in early phase...hypothesized that a range of common ovarian cancer predisposing germ- line BRCA1 gene mutations produce semi-functional proteins that are capable of...we have started our work examining exome sequences and gene expression in PARPi sensitive and resistance cancer cell lines . I attended and presented

Primordial germ cell biology at the beginning of the XXI century.

PubMed

De Felici, Massimo

2009-01-01

At the XIV Workshop on the Development and Function of the Reproductive Organs held at the Congress Centre of the University of Rome Tor Vergata, Monteporzio Catone, Rome, Italy, the introduction to the first session entitled Mammalian primordial germ cells dedicated to the memory of Anne McLaren, was the occasion for a concise review of the state of art of research on the biology of primordial germ cells (PGCs). This great, unforgettable scientist, who died in a car accident in July 2007, dedicated most of her studies to this field over the last 25 years. Topics briefly reviewed in this Meeting Report are: 1) how the germ line is determined; 2) what are the mechanisms underlying PGC migration; 3) to what extent PGC survival, proliferation and differentiation are cell autonomous or environmentally controlled processes and 4) how the potential for totipotency is retained in PGCs.

Bi-directional gap junction-mediated soma-germline communication is essential for spermatogenesis.

PubMed

Smendziuk, Christopher M; Messenberg, Anat; Vogl, A Wayne; Tanentzapf, Guy

2015-08-01

Soma-germline interactions play conserved essential roles in regulating cell proliferation, differentiation, patterning and homeostasis in the gonad. In the Drosophila testis, secreted signalling molecules of the JAK-STAT, Hedgehog, BMP and EGF pathways are used to mediate soma-germline communication. Here, we demonstrate that gap junctions may also mediate direct, bi-directional signalling between the soma and germ line. When gap junctions between the soma and germ line are disrupted, germline differentiation is blocked and germline stem cells are not maintained. In the soma, gap junctions are required to regulate proliferation and differentiation. Localization and RNAi-mediated knockdown studies reveal that gap junctions in the fly testis are heterotypic channels containing Zpg (Inx4) and Inx2 on the germ line and the soma side, respectively. Overall, our results show that bi-directional gap junction-mediated signalling is essential to coordinate the soma and germ line to ensure proper spermatogenesis in Drosophila. Moreover, we show that stem cell maintenance and differentiation in the testis are directed by gap junction-derived cues. © 2015. Published by The Company of Biologists Ltd.

Generation of germ cells in vitro in the era of induced pluripotent stem cells.

PubMed

Imamura, Masanori; Hikabe, Orie; Lin, Zachary Yu-Ching; Okano, Hideyuki

2014-01-01

Induced pluripotent stem cells (iPSCs) are stem cells that can be artificially generated via "cellular reprogramming" using gene transduction in somatic cells. iPSCs have enormous potential in stem-cell biology as they can give rise to numerous cell lineages, including the three germ layers. An evaluation of germ-line competency by blastocyst injection or tetraploid complementation, however, is critical for determining the developmental potential of mouse iPSCs towards germ cells. Recent studies have demonstrated that primordial germ cells obtained by the in vitro differentiation of iPSCs produce functional gametes as well as healthy offspring. These findings illustrate not only that iPSCs are developmentally similar to embryonic stem cells (ESCs), but also that somatic cells from adult tissues can produce gametes in vitro, that is, if they are reprogrammed into iPSCs. In this review, we discuss past and recent advances in the in vitro differentiation of germ cells using pluripotent stem cells, with an emphasis on ESCs and iPSCs. While this field of research is still at a stage of infancy, it holds great promises for investigating the mechanisms of germ-cell development, especially in humans, and for advancing reproductive and developmental engineering technologies in the future. © 2013 Wiley Periodicals, Inc.

Spondyloepiphseal dysplasia congenita in siblings born to unaffected parents: ? germ line mosaicism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mulla, W.; McDonald-McGinn, D.; Zackai, E.

1994-09-01

Germ line mosaicism has been used to explain the birth of more than one child affected with a dominantly inherited disorder born to unaffected parents. Furthermore, it has been confirmed clinically in families where recurrence in siblings was originally thought to be autosomal recessive, but were affected individuals have reproduced affected offspring. Firm evidence of germ line mosaicism using mutation analysis by molecular methods exists for some autosomal disorders. We present two siblings with spondyloepipheseal dysplasia congenita (SEDC) born to unaffected parents. This suggests the presence of germ line mosaicism in this entity. Patient 1 was born at 32 weeksmore » gestation to a G1P1 Puerto Rican mother. The pregnancy was complicated by polyhydramnios. The neonate, a short-limbed dwarf, died at 15 hours of age from respiratory distress and a compromised thoracic cavity. Patient 2, the sibling of patient 1 was born at 37 weeks gestation after a pregnancy complicated by polyhydramnios and prenatal ultrasound diagnosis of short-limbed dwarfism. The diagnosis of SEDC was made and, after review of the sibling`s postmortem X-rays, it was felt that she was similarly affected. The family history reveals no history of dwarfism or consanguinity. The SEDC is described as an autosomal dominant form of dwarfism with variable presentation including some cases that have been lethal in the neonatal period. SEDC is now believed to represent a family of collagen II mutations. Sporadic cases that have arisen in families with no history have been ascribed to new heterozygous mutations. Other families in which SEDC and SEMD recurred without a family history most likely represent germ line mosaicism. In these cases molecular studies should be pursued to document a collagen II mutation. We believe that germ line mosaicism is the most plausible explanation for recurrence in our family.« less

Use of pluripotent stem cells for reproductive medicine: are we there yet?

PubMed

Duggal, Galbha; Heindryckx, Björn; Deroo, Tom; De Sutter, Petra

2014-01-01

In recent years, pluripotent stem cells have demonstrated to be exciting tools to understand embryonic development, cell lineage specification, tissue generation and repair, and various other biological processes. In addition, the identification and isolation of germ line stem cells has given more insight into germ cell biology at the molecular level and into the underlying causes of infertility which was not possible earlier. The recent derivation of in vitro derived sperm and oocytes from pluripotent stem cells in the mouse model represents a major breakthrough in the field and substantiates the critical relevance of stem cells as a potential alternative resource for treating infertility. Although the past years have yielded compelling information in understanding germ cell development via in vitro stem cell assays, extended investigative research is necessary in order to derive fully functional 'artificial gametes' in a safe way for future therapeutic applications.

BRCA Mutation Frequency and Patterns of Treatment Response in BRCA Mutation–Positive Women With Ovarian Cancer: A Report From the Australian Ovarian Cancer Study Group

PubMed Central

Alsop, Kathryn; Fereday, Sian; Meldrum, Cliff; deFazio, Anna; Emmanuel, Catherine; George, Joshy; Dobrovic, Alexander; Birrer, Michael J.; Webb, Penelope M.; Stewart, Colin; Friedlander, Michael; Fox, Stephen; Bowtell, David; Mitchell, Gillian

2012-01-01

Purpose The frequency of BRCA1 and BRCA2 germ-line mutations in women with ovarian cancer is unclear; reports vary from 3% to 27%. The impact of germ-line mutation on response requires further investigation to understand its impact on treatment planning and clinical trial design. Patients and Methods Women with nonmucinous ovarian carcinoma (n = 1,001) enrolled onto a population-based, case-control study were screened for point mutations and large deletions in both genes. Survival outcomes and responses to multiple lines of chemotherapy were assessed. Results Germ-line mutations were found in 14.1% of patients overall, including 16.6% of serous cancer patients (high-grade serous, 22.6%); 44% had no reported family history of breast or ovarian cancer. Patients carrying germ-line mutations had improved rates of progression-free and overall survival. In the relapse setting, patients carrying mutations more frequently responded to both platin- and nonplatin-based regimens than mutation-negative patients, even in patients with early relapse after primary treatment. Mutation-negative patients who responded to multiple cycles of platin-based treatment were more likely to carry somatic BRCA1/2 mutations. Conclusion BRCA mutation status has a major influence on survival in ovarian cancer patients and should be an additional stratification factor in clinical trials. Treatment outcomes in BRCA1/2 carriers challenge conventional definitions of platin resistance, and mutation status may be able to contribute to decision making and systemic therapy selection in the relapse setting. Our data, together with the advent of poly(ADP-ribose) polymerase inhibitor trials, supports the recommendation that germ-line BRCA1/2 testing should be offered to all women diagnosed with nonmucinous, ovarian carcinoma, regardless of family history. PMID:22711857

Target sequence accessibility limits activation-induced cytidine deaminase activity in primary mediastinal B-cell lymphoma.

PubMed

Popov, Sergey W; Moldenhauer, Gerhard; Wotschke, Beate; Brüderlein, Silke; Barth, Thomas F; Dorsch, Karola; Ritz, Olga; Möller, Peter; Leithäuser, Frank

2007-07-15

Activation-induced cytidine deaminase (AID) initiates somatic hypermutation (SHM) and class switch recombination (CSR) in activated B lymphocytes and is potentially implicated in genomic instability of B-cell malignancies. For unknown reasons, B-cell neoplasms often lack SHM and CSR in spite of high AID expression. Here, we show that primary mediastinal B-cell lymphoma (PMBL), an immunoglobulin (Ig)-negative lymphoma that possesses hypermutated, class-switched Ig genes, expresses high levels of AID with an intact primary structure but does not do CSR in 14 of 16 cases analyzed. Absence of CSR coincided with low Ig germ-line transcription, whereas high level germ-line transcription was observed only in those two cases with active CSR. Interleukin-4/CD40L costimulation induced CSR and a marked up-regulation of germ-line transcription in the PMBL-derived cell line MedB-1. In the PMBL cell line Karpas 1106P, CSR was not inducible and germ-line transcription remained low on stimulation. However, Karpas 1106P, but not MedB-1, had ongoing SHM of the Ig gene and BCL6. These genes were transcribed in Karpas 1106P, whereas transcription was undetectable or low in MedB-1 cells. Thus, accessibility of the target sequences seems to be a major limiting factor for AID-dependent somatic gene diversification in PMBL.

The p53-Deficient Mouse as a Breast Cancer Model

DTIC Science & Technology

1995-10-01

M.A. Gryka , F.Z. Bischoff, M.A. Tain- Halachmi, R.T. Bronson, and R.A. Weinberg. 1994. Tumor sky, and S.H. Friend. 1990. Germ line p53 mutations in a...J. Kassel, M.A. Gryka , F.Z. Bischoff, Weaver-Feldhaus, W. Ding, Z. Gholami, P. Soderkvist, L. M.A. Tainsky, and S.H. Friend. 1990. Germ line p53

Germ-line epigenetic modification of the murine Avy allele by nutritional supplementation

PubMed Central

Cropley, Jennifer E.; Suter, Catherine M.; Beckman, Kenneth B.; Martin, David I. K.

2006-01-01

Environmental effects on phenotype can be mediated by epigenetic modifications. The epigenetic state of the murine Avy allele is highly variable, and determines phenotypic effects that vary in a mosaic spectrum that can be shifted by in utero exposure to methyl donor supplementation. We have asked if methyl donor supplementation affects the germ-line epigenetic state of the Avy allele. We find that the somatic epigenetic state of Avy is affected by in utero methyl donor supplementation only when the allele is paternally contributed. Exposure to methyl donor supplementation during midgestation shifts Avy phenotypes not only in the mice exposed as fetuses, but in their offspring. This finding indicates that methyl donors can change the epigenetic state of the Avy allele in the germ line, and that the altered state is retained through the epigenetic resetting that takes place in gametogenesis and embryogenesis. Thus a mother's diet may have an enduring influence on succeeding generations, independent of later changes in diet. Although other reports have suggested such heritable epigenetic changes, this study demonstrates that a specific mammalian gene can be subjected to germ-line epigenetic change. PMID:17101998

Germ-line epigenetic modification of the murine A vy allele by nutritional supplementation.

PubMed

Cropley, Jennifer E; Suter, Catherine M; Beckman, Kenneth B; Martin, David I K

2006-11-14

Environmental effects on phenotype can be mediated by epigenetic modifications. The epigenetic state of the murine A vy allele is highly variable, and determines phenotypic effects that vary in a mosaic spectrum that can be shifted by in utero exposure to methyl donor supplementation. We have asked if methyl donor supplementation affects the germ-line epigenetic state of the A vy allele. We find that the somatic epigenetic state of A vy is affected by in utero methyl donor supplementation only when the allele is paternally contributed. Exposure to methyl donor supplementation during midgestation shifts A vy phenotypes not only in the mice exposed as fetuses, but in their offspring. This finding indicates that methyl donors can change the epigenetic state of the A vy allele in the germ line, and that the altered state is retained through the epigenetic resetting that takes place in gametogenesis and embryogenesis. Thus a mother's diet may have an enduring influence on succeeding generations, independent of later changes in diet. Although other reports have suggested such heritable epigenetic changes, this study demonstrates that a specific mammalian gene can be subjected to germ-line epigenetic change.

SMARCB1/INI1 maternal germ line mosaicism in schwannomatosis.

PubMed

Hulsebos, T J M; Kenter, S B; Jakobs, M E; Baas, F; Chong, B; Delatycki, M B

2010-01-01

Schwannomatosis is characterized by the development of multiple schwannomas of the nervous system, but without the occurrence of vestibular schwannomas. Most cases of schwannomatosis are thought to be sporadic, representing the first case in a family due to a new mutation in the causative gene. We recently identified SMARCB1/INI1 as a schwannomatosis-predisposing gene. Here, we analyzed this gene in a schwannomatosis family with two affected children, but with clinically unaffected parents. Both affected individuals carried a constitutional SMARCB1 mutation, c.1118+ 1G>A, that changes the donor splice site sequence of intron 8, causing skipping of exon 8 and resulting in the in-frame deletion of 132 nucleotides in the transcript. The mutation was not evident in constitutional DNA of the parents. Haplotyping revealed that the chromosome 22 segment that carries the mutant SMARCB1 allele originated from the mother. She transferred the same chromosome 22 segment, however, with a wild-type SMARCB1 copy, to a third unaffected child. Our findings indicate that the mother is germ line mosaic for the SMARCB1 mutation. In conclusion, our study shows for the first time that germ line mosaicism may occur in schwannomatosis, which has implications for genetic counseling in this disease.

Overview of the Graphical User Interface for the GERM Code (GCR Event-Based Risk Model

NASA Technical Reports Server (NTRS)

Kim, Myung-Hee; Cucinotta, Francis A.

2010-01-01

The descriptions of biophysical events from heavy ions are of interest in radiobiology, cancer therapy, and space exploration. The biophysical description of the passage of heavy ions in tissue and shielding materials is best described by a stochastic approach that includes both ion track structure and nuclear interactions. A new computer model called the GCR Event-based Risk Model (GERM) code was developed for the description of biophysical events from heavy ion beams at the NASA Space Radiation Laboratory (NSRL). The GERM code calculates basic physical and biophysical quantities of high-energy protons and heavy ions that have been studied at NSRL for the purpose of simulating space radiobiological effects. For mono-energetic beams, the code evaluates the linear-energy transfer (LET), range (R), and absorption in tissue equivalent material for a given Charge (Z), Mass Number (A) and kinetic energy (E) of an ion. In addition, a set of biophysical properties are evaluated such as the Poisson distribution of ion or delta-ray hits for a specified cellular area, cell survival curves, and mutation and tumor probabilities. The GERM code also calculates the radiation transport of the beam line for either a fixed number of user-specified depths or at multiple positions along the Bragg curve of the particle. The contributions from primary ion and nuclear secondaries are evaluated. The GERM code accounts for the major nuclear interaction processes of importance for describing heavy ion beams, including nuclear fragmentation, elastic scattering, and knockout-cascade processes by using the quantum multiple scattering fragmentation (QMSFRG) model. The QMSFRG model has been shown to be in excellent agreement with available experimental data for nuclear fragmentation cross sections, and has been used by the GERM code for application to thick target experiments. The GERM code provides scientists participating in NSRL experiments with the data needed for the interpretation of their experiments, including the ability to model the beam line, the shielding of samples and sample holders, and the estimates of basic physical and biological outputs of the designed experiments. We present an overview of the GERM code GUI, as well as providing training applications.

Mitochondrial functionality in female reproduction.

PubMed

Gąsior, Łukasz; Daszkiewicz, Regina; Ogórek, Mateusz; Polański, Zbigniew

2017-01-04

In most animal species female germ cells are the source of mitochondrial genome for the whole body of individuals. As a source of mitochondrial DNA for future generations the mitochondria in the female germ line undergo dynamic quantitative and qualitative changes. In addition to maintaining the intact template of mitochondrial genome from one generation to another, mitochondrial role in oocytes is much more complex and pleiotropic. The quality of mitochondria determines the ability of meiotic divisions, fertilization ability, and activation after fertilization or sustaining development of a new embryo. The presence of normal number of functional mitochondria is also crucial for proper implantation and pregnancy maintaining. This article addresses issues of mitochondrial role and function in mammalian oocyte and presents new approaches in studies of mitochondrial function in female germ cells.

Differential expression of conserved germ line markers and delayed segregation of male and female primordial germ cells in a hermaphrodite, the leech helobdella.

PubMed

Cho, Sung-Jin; Vallès, Yvonne; Weisblat, David A

2014-02-01

In sexually reproducing animals, primordial germ cells (PGCs) are often set aside early in embryogenesis, a strategy that minimizes the risk of genomic damage associated with replication and mitosis during the cell cycle. Here, we have used germ line markers (piwi, vasa, and nanos) and microinjected cell lineage tracers to show that PGC specification in the leech genus Helobdella follows a different scenario: in this hermaphrodite, the male and female PGCs segregate from somatic lineages only after more than 20 rounds of zygotic mitosis; the male and female PGCs share the same (mesodermal) cell lineage for 19 rounds of zygotic mitosis. Moreover, while all three markers are expressed in both male and female reproductive tissues of the adult, they are expressed differentially between the male and female PGCs of the developing embryo: piwi and vasa are expressed preferentially in female PGCs at a time when nanos is expressed preferentially in male PGCs. A priori, the delayed segregation of male and female PGCs from somatic tissues and from one another increases the probability of mutations affecting both male and female PGCs of a given individual. We speculate that this suite of features, combined with a capacity for self-fertilization, may contribute to the dramatically rearranged genome of Helobdella robusta relative to other animals.

Differential Expression of Conserved Germ Line Markers and Delayed Segregation of Male and Female Primordial Germ Cells in a Hermaphrodite, the Leech Helobdella

PubMed Central

Cho, Sung-Jin; Vallès, Yvonne; Weisblat, David A.

2014-01-01

In sexually reproducing animals, primordial germ cells (PGCs) are often set aside early in embryogenesis, a strategy that minimizes the risk of genomic damage associated with replication and mitosis during the cell cycle. Here, we have used germ line markers (piwi, vasa, and nanos) and microinjected cell lineage tracers to show that PGC specification in the leech genus Helobdella follows a different scenario: in this hermaphrodite, the male and female PGCs segregate from somatic lineages only after more than 20 rounds of zygotic mitosis; the male and female PGCs share the same (mesodermal) cell lineage for 19 rounds of zygotic mitosis. Moreover, while all three markers are expressed in both male and female reproductive tissues of the adult, they are expressed differentially between the male and female PGCs of the developing embryo: piwi and vasa are expressed preferentially in female PGCs at a time when nanos is expressed preferentially in male PGCs. A priori, the delayed segregation of male and female PGCs from somatic tissues and from one another increases the probability of mutations affecting both male and female PGCs of a given individual. We speculate that this suite of features, combined with a capacity for self-fertilization, may contribute to the dramatically rearranged genome of Helobdella robusta relative to other animals. PMID:24217283

piRNA pathway targets active LINE1 elements to establish the repressive H3K9me3 mark in germ cells

PubMed Central

Pezic, Dubravka; Manakov, Sergei A.; Sachidanandam, Ravi; Aravin, Alexei A.

2014-01-01

Transposable elements (TEs) occupy a large fraction of metazoan genomes and pose a constant threat to genomic integrity. This threat is particularly critical in germ cells, as changes in the genome that are induced by TEs will be transmitted to the next generation. Small noncoding piwi-interacting RNAs (piRNAs) recognize and silence a diverse set of TEs in germ cells. In mice, piRNA-guided transposon repression correlates with establishment of CpG DNA methylation on their sequences, yet the mechanism and the spectrum of genomic targets of piRNA silencing are unknown. Here we show that in addition to DNA methylation, the piRNA pathway is required to maintain a high level of the repressive H3K9me3 histone modification on long interspersed nuclear elements (LINEs) in germ cells. piRNA-dependent chromatin repression targets exclusively full-length elements of actively transposing LINE families, demonstrating the remarkable ability of the piRNA pathway to recognize active elements among the large number of genomic transposon fragments. PMID:24939875

Germ cell regeneration-mediated, enhanced mutagenesis in the ascidian Ciona intestinalis reveals flexible germ cell formation from different somatic cells.

PubMed

Yoshida, Keita; Hozumi, Akiko; Treen, Nicholas; Sakuma, Tetsushi; Yamamoto, Takashi; Shirae-Kurabayashi, Maki; Sasakura, Yasunori

2017-03-15

The ascidian Ciona intestinalis has a high regeneration capacity that enables the regeneration of artificially removed primordial germ cells (PGCs) from somatic cells. We utilized PGC regeneration to establish efficient methods of germ line mutagenesis with transcription activator-like effector nucleases (TALENs). When PGCs were artificially removed from animals in which a TALEN pair was expressed, somatic cells harboring mutations in the target gene were converted into germ cells, this germ cell population exhibited higher mutation rates than animals not subjected to PGC removal. PGC regeneration enables us to use TALEN expression vectors of specific somatic tissues for germ cell mutagenesis. Unexpectedly, cis elements for epidermis, neural tissue and muscle could be used for germ cell mutagenesis, indicating there are multiple sources of regenerated PGCs, suggesting a flexibility of differentiated Ciona somatic cells to regain totipotency. Sperm and eggs of a single hermaphroditic, PGC regenerated animal typically have different mutations, suggesting they arise from different cells. PGCs can be generated from somatic cells even though the maternal PGCs are not removed, suggesting that the PGC regeneration is not solely an artificial event but could have an endogenous function in Ciona. This study provides a technical innovation in the genome-editing methods, including easy establishment of mutant lines. Moreover, this study suggests cellular mechanisms and the potential evolutionary significance of PGC regeneration in Ciona. Copyright © 2017 Elsevier Inc. All rights reserved.

Notch Signaling Regulates Ovarian Follicle Formation and Coordinates Follicular Growth

PubMed Central

Vanorny, Dallas A.; Prasasya, Rexxi D.; Chalpe, Abha J.; Kilen, Signe M.

2014-01-01

Ovarian follicles form through a process in which somatic pregranulosa cells encapsulate individual germ cells from germ cell syncytia. Complementary expression of the Notch ligand, Jagged1, in germ cells and the Notch receptor, Notch2, in pregranulosa cells suggests a role for Notch signaling in mediating cellular interactions during follicle assembly. Using a Notch reporter mouse, we demonstrate that Notch signaling is active within somatic cells of the embryonic ovary, and these cells undergo dramatic reorganization during follicle histogenesis. This coincides with a significant increase in the expression of the ligands, Jagged1 and Jagged2; the receptor, Notch2; and the target genes, Hes1 and Hey2. Histological examination of ovaries from mice with conditional deletion of Jagged1 within germ cells (J1 knockout [J1KO]) or Notch2 within granulosa cells (N2 knockout [N2KO]) reveals changes in follicle dynamics, including perturbations in the primordial follicle pool and antral follicle development. J1KO and N2KO ovaries also contain multi-oocytic follicles, which represent a failure to resolve germ cell syncytia, and follicles with enlarged oocytes but lacking somatic cell growth, signifying a potential role of Notch signaling in follicle activation and the coordination of follicle development. We also observed decreased cell proliferation and increased apoptosis in the somatic cells of both conditional knockout lines. As a consequence of these defects, J1KO female mice are subfertile; however, N2KO female mice remain fertile. This study demonstrates important functions for Jagged1 and Notch2 in the resolution of germ cell syncytia and the coordination of somatic and germ cell growth within follicles of the mouse ovary. PMID:24552588

In vitro functional screening as a means to identify new plasticizers devoid of reproductive toxicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boisvert, Annie; Jones, Steven; Issop, Leeyah

Plasticizers are indispensable additives providing flexibility and malleability to plastics. Among them, several phthalates, including di (2-ethylhexyl) phthalate (DEHP), have emerged as endocrine disruptors, leading to their restriction in consumer products and creating a need for new, safer plasticizers. The goal of this project was to use in vitro functional screening tools to select novel non-toxic plasticizers suitable for further in vivo evaluation. A panel of novel compounds with satisfactory plasticizer properties and biodegradability were tested, along with several commercial plasticizers, such as diisononyl-cyclohexane-1,2-dicarboxylate (DINCH®). MEHP, the monoester metabolite of DEHP was also included as reference compound. Because phthalates targetmore » mainly testicular function, including androgen production and spermatogenesis, we used the mouse MA-10 Leydig and C18-4 spermatogonial cell lines as surrogates to examine cell survival, proliferation, steroidogenesis and mitochondrial integrity. The most promising compounds were further assessed on organ cultures of rat fetal and neonatal testes, corresponding to sensitive developmental windows. Dose-response studies revealed the toxicity of most maleates and fumarates, while identifying several dibenzoate and succinate plasticizers as innocuous on Leydig and germ cells. Interestingly, DINCH®, a plasticizer marketed as a safe alternative to phthalates, exerted a biphasic effect on steroid production in MA-10 and fetal Leydig cells. MEHP was the only plasticizer inducing the formation of multinucleated germ cells (MNG) in organ culture. Overall, organ cultures corroborated the cell line data, identifying one dibenzoate and one succinate as the most promising candidates. The adoption of such collaborative approaches for developing new chemicals should help prevent the development of compounds potentially harmful to human health. - Highlights: • Phthalate plasticizers exert toxic effects on male reproduction. • Reproductive toxicity of new plasticizers was assessed by functional assays. • Mouse Leydig and germ cell lines, and rat perinatal testis cultures were used. • Survival, proliferation, steroidogenesis, abnormal germ cell formation were examined. • Reproductive toxic and innocuous plasticizer candidates were identified.« less

Genetic modification of the human germ line: The reasons why this project has no future.

PubMed

Morange, Michel

2015-01-01

Modification of the human germ line has remained a distant but valuable objective for most biologists since the emergence of genetics (and even before). To study the historical transformations of this project, I have selected three periods - the 1930s, at the pinnacle of eugenics, around 1974 when molecular biology triumphed, and today - and have adopted three criteria to estimate the feasibility of this project: the state of scientific knowledge, the existence of suitable tools, and societal demands. Although the long-awaited techniques to modify the germ line are now available, I will show that most of the expectations behind this project have disappeared, or are considered as being reachable by highly different strategies. Copyright © 2015 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Cell fusion as the formation mechanism of unreduced gametes in the gynogenetic diploid hybrid fish.

PubMed

Wang, Jing; Liu, Qingfeng; Luo, Kaikun; Chen, Xuan; Xiao, Jun; Zhang, Chun; Tao, Min; Zhao, Rurong; Liu, Shaojun

2016-08-17

The gynogenetic diploid hybrid clone line (GDH) derived from red crucian carp (♀ RCC) × common carp (♂ CC) possesses the unusual reproductive trait of producing unreduced diploid eggs. To identify the mechanism underlying this phenomenon, we examined the structure, in vivo developmental process and in vitro dynamic development of the GDH gonad. In summary, compared with RCC and CC, GDH showed certain special straits. First, a high frequency (84.7%) of germ cell fusion occurred in gonadal tissue culture in vitro as observed by time-lapse microscopy. Second, microstructural and ultrastructural observation showed numerous binucleated and multinucleated germ cells in the gonad, providing evidence of germ cell fusion in vivo. By contrast, in the diploid RCC and CC ovaries, neither cell fusion nor multinucleated cells were observed during the development of gonads. Third, the ovary of GDH remained at stage I for 10 months, whereas those of RCC and CC remained at that stage for 2 months, indicating that the GDH germ cells underwent abnormal development before meiosis. This report is the first to demonstrate that cell fusion facilitates the formation of unreduced gametes in vertebrates, which is a valuable finding for both evolutionary biology and reproductive biology.

Sequence and expression pattern of the germ line marker vasa in honey bees and stingless bees

PubMed Central

2009-01-01

Queens and workers of social insects differ in the rates of egg laying. Using genomic information we determined the sequence of vasa, a highly conserved gene specific to the germ line of metazoans, for the honey bee and four stingless bees. The vasa sequence of social bees differed from that of other insects in two motifs. By RT-PCR we confirmed the germ line specificity of Amvasa expression in honey bees. In situ hybridization on ovarioles showed that Amvasa is expressed throughout the germarium, except for the transition zone beneath the terminal filament. A diffuse vasa signal was also seen in terminal filaments suggesting the presence of germ line cells. Oocytes showed elevated levels of Amvasa transcripts in the lower germarium and after follicles became segregated. In previtellogenic follicles, Amvasa transcription was detected in the trophocytes, which appear to supply its mRNA to the growing oocyte. A similar picture was obtained for ovarioles of the stingless bee Melipona quadrifasciata, except that Amvasa expression was higher in the oocytes of previtellogenic follicles. The social bees differ in this respect from Drosophila, the model system for insect oogenesis, suggesting that changes in the sequence and expression pattern of vasa may have occurred during social evolution. PMID:21637523

MSH6 and MSH3 are rarely involved in genetic predisposition to nonpolypotic colon cancer.

PubMed

Huang, J; Kuismanen, S A; Liu, T; Chadwick, R B; Johnson, C K; Stevens, M W; Richards, S K; Meek, J E; Gao, X; Wright, F A; Mecklin, J P; Järvinen, H J; Grönberg, H; Bisgaard, M L; Lindblom, A; Peltomäki, P

2001-02-15

A set of 90 nonpolypotic colon cancer families in which germ-line mutations of MSH2 and MLH1 had been excluded were screened for mutations in two additional DNA mismatch repair genes, MSH6 and MSH3. Kindreds fulfilling and not fulfilling the Amsterdam I criteria, showing early and late onset colorectal (and other) cancers, and having microsatellite stable and unstable tumors were included. Two partly parallel approaches were used: genetic linkage analysis (19 large families) and the protein truncation test (85, mostly smaller, families). Whereas MSH3 was not involved in any family, a large Amsterdam-positive, late-onset family showed a novel germ-line mutation in MSH6 (deletion of CT at nucleotide 3052 in exon 4). The mutation was identified through genetic linkage (multipoint lod score 2.4) and subsequent sequencing of MSH6. Furthermore, the entire MSH6 gene was sequenced exon by exon in families with frameshift mutations in the (C)8 tract in tumors, previously suggested as a predictor of MSH6 germ-line mutations; no mutations were found. We conclude that germ-line involvement of MSH6 and MSH3 is rare and that other genes are likely to account for a majority of MSH2-, MLH1-mutation negative families with nonpolypotic colon cancer.

Multiple primary tumors of the upper aerodigestive tract: is there a role for constitutional mutations in the p53 gene?

PubMed

Gallo, O; Sardi, I; Pepe, G; Franchi, A; Attanasio, M; Giusti, B; Bocciolini, C; Abbate, R

1999-07-19

Head-and-neck cancer (HNC) patients have a high risk of developing second primary tumors of the upper aerodigestive tract, the main cause of death. Although the roles of tobacco and diet in multiple head-and-neck carcinogenesis have been thoroughly investigated, little is known about individual genetic susceptibility factors involved in this process. Genomic instability, reflecting the propensity and the susceptibility of the genome to acquire multiple alterations, could be considered a driving force behind multiple carcinogenesis. Mutation of the p53 tumor-suppressor gene has been proposed to play an important role in this process. Therefore, we evaluated the incidence of inherited p53 germ-line alteration(s) in a population of 24 consecutive HNC patients and their first-degree relatives affected by multiple malignancies as well as the occurrence of p53 somatic acquired mutation(s) in 16 cancers, including first and second primaries from 5 HNCs of the same group. Mutations in exons 4-11 of the p53 gene were investigated using SSCP-PCR analysis and DNA sequencing. Analysis was extended to the peripheral blood and cancer biopsies available from first-degree relatives of cancer-prone families with p53 germ-line mutations. p53 germ-line mutations were identified in the peripheral blood and corresponding cancers of 3 HNC patients who had multiple malignancies. The only missense mutation detected was mapped in exon 6; it is a GTG to GAG substitution with an amino acid change from Val to Glu at codon 197. The remaining 2 p53 germ-line mutations were single-nucleotide substitutions without amino acid change in exon 6 (codon 213, CGA to CGG) and in exon 8 (codon 295, CCT to CCC), respectively. These mutations were found in HNC patients with a family history of cancer. Abnormal expression of wild-type p53 protein in normal and pathological tissues from patients with the same sense single-nucleotide substitutions was detected by immuno-histochemistry.

Differential Nanos 2 protein stability results in selective germ cell accumulation in the sea urchin

PubMed Central

Oulhen, Nathalie; Wessel, Gary M.

2016-01-01

Nanos is a translational regulator required for the survival and maintenance of primordial germ cells. In the sea urchin, Strongylocentrotus purpuratus (Sp), Nanos 2 mRNA is broadly transcribed but accumulates specifically in the small micromere (sMic) lineage, in part because of the 3′UTR element GNARLE leads to turnover in somatic cells but retention in the sMics. Here we found that the Nanos 2 protein is also selectively stabilized; it is initially translated throughout the embryo but turned over in the future somatic cells and retained only in the sMics, the future germ line in this animal. This differential stability of Nanos protein is dependent on the open reading frame (ORF), and is independent of the sumoylation and ubiquitylation pathways. Manipulation of the ORF indicates that 68 amino acids in the N terminus of the Nanos protein are essential for its stability in the sMics whereas a 45 amino acid element adjacent to the zinc fingers targets its degradation. Further, this regulation of Nanos protein is cell autonomous, following formation of the germ line. These results are paradigmatic for the unique presence of Nanos in the germ line by a combination of selective RNA retention, distinctive translational control mechanisms (Oulhen et al., 2013), and now also by defined Nanos protein stability. PMID:27424271

Differential Nanos 2 protein stability results in selective germ cell accumulation in the sea urchin.

PubMed

Oulhen, Nathalie; Wessel, Gary M

2016-10-01

Nanos is a translational regulator required for the survival and maintenance of primordial germ cells. In the sea urchin, Strongylocentrotus purpuratus (Sp), Nanos 2 mRNA is broadly transcribed but accumulates specifically in the small micromere (sMic) lineage, in part because of the 3'UTR element GNARLE leads to turnover in somatic cells but retention in the sMics. Here we found that the Nanos 2 protein is also selectively stabilized; it is initially translated throughout the embryo but turned over in the future somatic cells and retained only in the sMics, the future germ line in this animal. This differential stability of Nanos protein is dependent on the open reading frame (ORF), and is independent of the sumoylation and ubiquitylation pathways. Manipulation of the ORF indicates that 68 amino acids in the N terminus of the Nanos protein are essential for its stability in the sMics whereas a 45 amino acid element adjacent to the zinc fingers targets its degradation. Further, this regulation of Nanos protein is cell autonomous, following formation of the germ line. These results are paradigmatic for the unique presence of Nanos in the germ line by a combination of selective RNA retention, distinctive translational control mechanisms (Oulhen et al., 2013), and now also by defined Nanos protein stability. Copyright © 2016 Elsevier Inc. All rights reserved.

DNA methylation analysis reveals distinct methylation signatures in pediatric germ cell tumors.

PubMed

Amatruda, James F; Ross, Julie A; Christensen, Brock; Fustino, Nicholas J; Chen, Kenneth S; Hooten, Anthony J; Nelson, Heather; Kuriger, Jacquelyn K; Rakheja, Dinesh; Frazier, A Lindsay; Poynter, Jenny N

2013-06-27

Aberrant DNA methylation is a prominent feature of many cancers, and may be especially relevant in germ cell tumors (GCTs) due to the extensive epigenetic reprogramming that occurs in the germ line during normal development. We used the Illumina GoldenGate Cancer Methylation Panel to compare DNA methylation in the three main histologic subtypes of pediatric GCTs (germinoma, teratoma and yolk sac tumor (YST); N = 51) and used recursively partitioned mixture models (RPMM) to test associations between methylation pattern and tumor and demographic characteristics. We identified genes and pathways that were differentially methylated using generalized linear models and Ingenuity Pathway Analysis. We also measured global DNA methylation at LINE1 elements and evaluated methylation at selected imprinted loci using pyrosequencing. Methylation patterns differed by tumor histology, with 18/19 YSTs forming a distinct methylation class. Four pathways showed significant enrichment for YSTs, including a human embryonic stem cell pluripotency pathway. We identified 190 CpG loci with significant methylation differences in mature and immature teratomas (q < 0.05), including a number of CpGs in stem cell and pluripotency-related pathways. Both YST and germinoma showed significantly lower methylation at LINE1 elements compared with normal adjacent tissue while there was no difference between teratoma (mature and immature) and normal tissue. DNA methylation at imprinted loci differed significantly by tumor histology and location. Understanding methylation patterns may identify the developmental stage at which the GCT arose and the at-risk period when environmental exposures could be most harmful. Further, identification of relevant genetic pathways could lead to the development of new targets for therapy.

Recurrence of Marfan syndrome as a result of parental germ-line mosaicism for an FBN1 mutation.

PubMed Central

Rantamäki, T; Kaitila, I; Syvänen, A C; Lukka, M; Peltonen, L

1999-01-01

Mutations in the FBN1 gene cause Marfan syndrome (MFS), a dominantly inherited connective tissue disease. Almost all the identified FBN1mutations have been family specific, and the rate of new mutations is high. We report here a de novo FBN1mutation that was identified in two sisters with MFS born to clinically unaffected parents. The paternity and maternity were unequivocally confirmed by genotyping. Although one of the parents had to be an obligatory carrier for the mutation, we could not detect the mutation in the leukocyte DNA of either parent. To identify which parent was a mosaic for the mutation we analyzed several tissues from both parents, with a quantitative and sensitive solid-phase minisequencing method. The mutation was not, however, detectable in any of the analyzed tissues. Although the mutation could not be identified in a sperm sample from the father or in samples of multiple tissue from the mother, we concluded that the mother was the likely mosaic parent and that the mutation must have occurred during the early development of her germ-line cells. Mosaicism confined to germ-line cells has rarely been reported, and this report of mosaicism for the FBN1 mutation in MFS represents an important case, in light of the evaluation of the recurrence risk in genetic counseling of families with MFS. PMID:10090884

Homeland security in the C. elegans germ line: insights into the biogenesis and function of piRNAs.

PubMed

Kasper, Dionna M; Gardner, Kathryn E; Reinke, Valerie

2014-01-01

While most eukaryotic genomes contain transposable elements that can provide select evolutionary advantages to a given organism, failure to tightly control the mobility of such transposable elements can result in compromised genomic integrity of both parental and subsequent generations. Together with the Piwi subfamily of Argonaute proteins, small, non-coding Piwi-interacting RNAs (piRNAs) primarily function in the germ line to defend the genome against the potentially deleterious effects that can be caused by transposition. Here, we describe recent discoveries concerning the biogenesis and function of piRNAs in the nematode Caenorhabditis elegans, illuminating how the faithful production of these mature species can impart a robust defense mechanism for the germ line to counteract problems caused by foreign genetic elements across successive generations by contributing to the epigenetic memory of non-self vs. self.

Dynamics associated with spontaneous differentiation of ovarian stem cells in vitro

PubMed Central

2014-01-01

Background Recent studies suggest that ovarian germ line stem cells replenish oocyte-pool in adult stage, and challenge the central doctrine of ‘fixed germ cell pool’ in mammalian reproductive biology. Two distinct populations of spherical stem cells with high nucleo-cytoplasmic ratio have been recently identified in the adult mammalian ovary surface epithelium (OSE) including nuclear OCT-4A positive very small embryonic-like (VSELs) and cytoplasmic OCT-4 expressing ovarian germ stem cells (OGSCs). Three weeks culture of scraped OSE cells results in spontaneous differentiation of the stem cells into oocyte-like, parthenote-like, embryoid body-like structures and also embryonic stem cell-like colonies whereas epithelial cells attach and transform into a bed of mesenchymal cells. Present study was undertaken, to further characterize ovarian stem cells and to comprehend better the process of spontaneous differentiation of ovarian stem cells into oocyte-like structures in vitro. Methods Ovarian stem cells were enriched by immunomagnetic sorting using SSEA-4 as a cell surface marker and were further characterized. Stem cells and clusters of OGSCs (reminiscent of germ cell nests in fetal ovaries), were characterized by immuno-localization for stem and germ cell specific markers and spontaneous differentiation in OSE cultures was studied by live cell imaging. Results Differential expression of markers specific for pluripotent VSELs (nuclear OCT-4A, SSEA-4, CD133), OGSCs (cytoplasmic OCT-4) primordial germ cells (FRAGILIS, STELLA, VASA) and germ cells (DAZL, GDF-9, SCP-3) were studied. Within one week of culture, stem cells became bigger in size, developed abundant cytoplasm, differentiated into germ cells, revealed presence of Balbiani body-like structure (mitochondrial cloud) and exhibited characteristic cytoplasmic streaming. Conclusions Presence of germ cell nests, Balbiani body-like structures and cytoplasmic streaming extensively described during fetal ovary development, are indeed well recapitulated during in vitro oogenesis in adult OSE cultures along with characteristic expression of stem/germ cell/oocyte markers. Further studies are required to assess the genetic integrity of in vitro derived oocytes before harnessing their clinical potential. Advance in our knowledge about germ cell differentiation from stem cells will enable researchers to design better in vitro strategies which in turn may have relevance to reproductive biology and regenerative medicine. PMID:24568237

Identification of a subgroup with worse prognosis among patients with poor-risk testicular germ cell tumor.

PubMed

Kojima, Takahiro; Kawai, Koji; Tsuchiya, Kunihiko; Abe, Takashige; Shinohara, Nobuo; Tanaka, Toshiaki; Masumori, Naoya; Yamada, Shigeyuki; Arai, Yoichi; Narita, Shintaro; Tsuchiya, Norihiko; Habuchi, Tomonori; Nishiyama, Hiroyuki

2015-10-01

To clarify the significance of the International Germ Cell Cancer Collaborative Group classification in the 2000s, especially in intermediate- and poor-prognosis testicular germ cell tumor in Japan. We retrospectively analyzed 117 patients with intermediate- and poor-prognosis testicular non-seminomatous germ cell tumor treated at five university hospitals in Japan between 2000 and 2010. Data collected included age, levels of tumor markers, spread to non-pulmonary visceral metastases, treatment details and survival. The median follow-up period of all patients was 57 months. A total of 50 patients (43%) were classified as having intermediate prognosis, and 67 patients (57%) as poor prognosis according to the International Germ Cell Cancer Collaborative Group classification. As first-line chemotherapy, 92 patients (79%) received bleomycin, etoposide and cisplatin. Of all patients, 74 patients (63%) received second-line chemotherapy. The most commonly used second-line chemotherapy regimens were a combination of taxanes, ifosfamide and platinum in 49 cases (66%). Overall, 33 patients (28%) received third-line chemotherapy. A total of 88 patients (75%) underwent post-chemotherapy surgery. The 5-year overall survival for intermediate (n = 50) and poor prognosis (n = 67) was 89% and 83% (P = 0.21), respectively. In poor prognosis patients, patients with two or more risk factors (any of high lactic dehydrogenase, alpha-fetoprotein and human chorionic gonadotropin levels, and presence of non-pulmonary visceral metastases) had significantly worse survival than those with only one risk factor (71% and 91%, respectively, P = 0.01). The 5-year overall survivals of poor-prognosis testicular non-seminomatous germ cell tumor patients reached 83%. Further stratification of poor-prognosis patients based on a number of risk factors has the potential to further identify those with poorer prognosis. © 2015 The Japanese Urological Association.

Nematode development after removal of egg cytoplasm: absence of localized unbound determinants.

PubMed

Laufer, J S; von Ehrenstein, G

1981-01-23

Embryos of Caenorhabditis elegans develop into fertile adults after cell fragments, containing presumptive cytoplasm of somatic and germ line precursors, are extruded from uncleaved eggs or early blastomeres through laser-induced holes in the eggshells. This suggests that the determinate development of this worm is not dependent on the prelocalization of determinants in specific regions of the egg cytoplasm.

Expression of GFP under the control of the RNA helicase VASA permits fluorescence-activated cell sorting isolation of human primordial germ cells.

PubMed

Tilgner, Katarzyna; Atkinson, Stuart P; Yung, Sun; Golebiewska, Anna; Stojkovic, Miodrag; Moreno, Ruben; Lako, Majlinda; Armstrong, Lyle

2010-01-01

The isolation of significant numbers of human primordial germ cells at several developmental stages is important for investigations of the mechanisms by which they are able to undergo epigenetic reprogramming. Only small numbers of these cells can be obtained from embryos of appropriate developmental stages, so the differentiation of human embryonic stem cells is essential to obtain sufficient numbers of primordial germ cells to permit epigenetic examination. Despite progress in the enrichment of human primordial germ cells using fluorescence-activated cell sorting (FACS), there is still no definitive marker of the germ cell phenotype. Expression of the widely conserved RNA helicase VASA is restricted to germline cells, but in contrast to species such as Mus musculus in which reporter constructs expressing green fluorescent protein (GFP) under the control of a Vasa promoter have been developed, such reporter systems are lacking in human in vitro models. We report here the generation and characterization of human embryonic stem cell lines stably carrying a VASA-pEGFP-1 reporter construct that expresses GFP in a population of differentiating human embryonic stem cells that show expression of characteristic markers of primordial germ cells. This population shows a different pattern of chromatin modifications to those obtained by FACS enrichment of Stage Specific Antigen one expressing cells in our previous publication.

Mitochondrial DNA sequence variation in human evolution and disease.

PubMed

Wallace, D C

1994-09-13

Germ-line and somatic mtDNA mutations are hypothesized to act together to shape our history and our health. Germ-line mtDNA mutations, both ancient and recent, have been associated with a variety of degenerative diseases. Mildly to moderately deleterious germ-line mutations, like neutral polymorphisms, have become established in the distant past through genetic drift but now may predispose certain individuals to late-onset degenerative diseases. As an example, a homoplasmic, Caucasian, tRNA(Gln) mutation at nucleotide pair (np) 4336 has been observed in 5% of Alzheimer disease and Parkinson disease patients and may contribute to the multifactorial etiology of these diseases. Moderately to severely deleterious germ-line mutations, on the other hand, appear repeatedly but are eliminated by selection. Hence, all extant mutations of this class are recent and associated with more devastating diseases of young adults and children. Representative of these mutations is a heteroplasmic mutation in MTND6 at np 14459 whose clinical presentations range from adult-onset blindness to pediatric dystonia and basal ganglial degeneration. To the inherited mutations are added somatic mtDNA mutations which accumulate in random arrays within stable tissues. These mutations provide a molecular clock that measures our age and may cause a progressive decline in tissue energy output that could precipitate the onset of degenerative diseases in individuals harboring inherited deleterious mutations.

Selfish cells in altruistic cell society - a theoretical oncology.

PubMed

Chigira, M

1993-09-01

In multicellular organisms, internal evolution of individual cells is strictly forbidden and 'evolutional' DNA replication should be performed only by the sexual reproduction system. Wholistic negative control system called 'homeostasis' serves all service to germ line cells. All somatic cells are altruistic to the germ line cells. However, in malignant tumors, it seems that individual cells replicate and behave 'selfishly' and evolve against the internal microenvironment. Tumor cells only express the occult selfishness which is programmed in normal cells a priori. This phenomenon is based on the failure of identical DNA replication, and results in 'autonomy' and 'anomie' of cellular society as shown in tumor cells. Genetic programs of normal cells connote this cellular autonomy and anomie introduced by the deletion of regulators on structure genes. It is rather paradoxical that the somatic cells get their freedom from wholistic negative regulation programmed internally. However, this is not a true paradox, since multicellular organisms have clearly been evolved from 'monads' in which cells proliferate without wholistic regulation. Somatic cells revolt against germ cell DNA, called 'selfish replicator' by Dawkins. It is an inevitable destiny that the 'selfishness' coded in genome should be revenged by itself. Selfish replicator in germ cell line should be revolted by its selfishness in the expansion of somatic cells, since they have an orthogenesis to get more selfishness in order to increase their genome. Tumor heterogeneity and progression can be fully explained by this self-contradictory process which produces heterogeneous gene copies different from the original clone in the tumor, although 'selfish' gene replication is the final target of being. Furthermore, we have to discard the concept of clonality of tumor cells since genetic instability is a fundamental feature of tumors. Finally, tumor cells and proto-oncogenes can be considered as the ultimate parasite to germ line cells.

The Individual and Population Genetics of Antibody Immunity.

PubMed

Watson, Corey T; Glanville, Jacob; Marasco, Wayne A

2017-07-01

Antibodies (Abs) produced by immunoglobulin (IG) genes are the most diverse proteins expressed in humans. While part of this diversity is generated by recombination during B-cell development and mutations during affinity maturation, the germ-line IG loci are also diverse across human populations and ethnicities. Recently, proof-of-concept studies have demonstrated genotype-phenotype correlations between specific IG germ-line variants and the quality of Ab responses during vaccination and disease. However, the functional consequences of IG genetic variation in Ab function and immunological outcomes remain underexplored. In this opinion article, we outline interconnections between IG genomic diversity and Ab-expressed repertoires and structure. We further propose a strategy for integrating IG genotyping with functional Ab profiling data as a means to better predict and optimize humoral responses in genetically diverse human populations, with immediate implications for personalized medicine. Copyright © 2017 Elsevier Ltd. All rights reserved.

DEPS-1 promotes P-granule assembly and RNA interference in C. elegans germ cells

PubMed Central

Spike, Caroline A.; Bader, Jason; Reinke, Valerie; Strome, Susan

2008-01-01

P granules are germ-cell-specific cytoplasmic structures containing RNA and protein, and required for proper germ cell development in C. elegans. PGL-1 and GLH-1 were previously identified as critical components of P granules. We have identified a new P-granule-associated protein, DEPS-1, the loss of which disrupts P-granule structure and function. DEPS-1 is required for the proper localization of PGL-1 to P granules, the accumulation of glh-1 mRNA and protein, and germ cell proliferation and fertility at elevated temperatures. In addition, DEPS-1 is required for RNA interference (RNAi) of germline-expressed genes, possibly because DEPS-1 promotes the accumulation of RDE-4, a dsRNA-binding protein required for RNAi. A genome wide analysis of gene expression in deps-1 mutant germ lines identified additional targets of DEPS-1 regulation, many of which are also regulated by the RNAi factor RDE-3. Our studies suggest that DEPS-1 is a key component of the P-granule assembly pathway and that its roles include promoting accumulation of some mRNAs, such as glh-1 and rde-4, and reducing accumulation of other mRNAs, perhaps by collaborating with RDE-3 to generate endogenous short interfering RNAs (endo-siRNAs). PMID:18234720

DEPS-1 promotes P-granule assembly and RNA interference in C. elegans germ cells.

PubMed

Spike, Caroline A; Bader, Jason; Reinke, Valerie; Strome, Susan

2008-03-01

P granules are germ-cell-specific cytoplasmic structures containing RNA and protein, and required for proper germ cell development in C. elegans. PGL-1 and GLH-1 were previously identified as critical components of P granules. We have identified a new P-granule-associated protein, DEPS-1, the loss of which disrupts P-granule structure and function. DEPS-1 is required for the proper localization of PGL-1 to P granules, the accumulation of glh-1 mRNA and protein, and germ cell proliferation and fertility at elevated temperatures. In addition, DEPS-1 is required for RNA interference (RNAi) of germline-expressed genes, possibly because DEPS-1 promotes the accumulation of RDE-4, a dsRNA-binding protein required for RNAi. A genome wide analysis of gene expression in deps-1 mutant germ lines identified additional targets of DEPS-1 regulation, many of which are also regulated by the RNAi factor RDE-3. Our studies suggest that DEPS-1 is a key component of the P-granule assembly pathway and that its roles include promoting accumulation of some mRNAs, such as glh-1 and rde-4, and reducing accumulation of other mRNAs, perhaps by collaborating with RDE-3 to generate endogenous short interfering RNAs (endo-siRNAs).

Development of transgenic strains for the biological control of the Mexican fruit fly, Anastrepha ludens

USDA-ARS?s Scientific Manuscript database

The Mexican fruit fly, Anastrepha ludens, is a highly significant agricultural pest species that has been genetically transformed with a piggyBac¬-based transposon vector system using independent vector and transposase helper plasmids. Estimated germ-line transformation frequencies were approximate...

Production of a maternal-zygotic medaka mutant using hybrid sterility.

PubMed

Shimada, Atsuko; Takeda, Hiroyuki

2008-08-01

Taking advantage of the characteristics that make hybrids between Japanese and Chinese medaka grow well, albeit sterile, we have developed a method of germ-line replacement in which these hybrids are used as hosts for the production of a maternal-zygotic mutant. The protocol is described herein.

Germ-line and somatic EPHA2 coding variants in lens aging and cataract.

PubMed

Bennett, Thomas M; M'Hamdi, Oussama; Hejtmancik, J Fielding; Shiels, Alan

2017-01-01

Rare germ-line mutations in the coding regions of the human EPHA2 gene (EPHA2) have been associated with inherited forms of pediatric cataract, whereas, frequent, non-coding, single nucleotide variants (SNVs) have been associated with age-related cataract. Here we sought to determine if germ-line EPHA2 coding SNVs were associated with age-related cataract in a case-control DNA panel (> 50 years) and if somatic EPHA2 coding SNVs were associated with lens aging and/or cataract in a post-mortem lens DNA panel (> 48 years). Micro-fluidic PCR amplification followed by targeted amplicon (exon) next-generation (deep) sequencing of EPHA2 (17-exons) afforded high read-depth coverage (1000x) for > 82% of reads in the cataract case-control panel (161 cases, 64 controls) and > 70% of reads in the post-mortem lens panel (35 clear lens pairs, 22 cataract lens pairs). Novel and reference (known) missense SNVs in EPHA2 that were predicted in silico to be functionally damaging were found in both cases and controls from the age-related cataract panel at variant allele frequencies (VAFs) consistent with germ-line transmission (VAF > 20%). Similarly, both novel and reference missense SNVs in EPHA2 were found in the post-mortem lens panel at VAFs consistent with a somatic origin (VAF > 3%). The majority of SNVs found in the cataract case-control panel and post-mortem lens panel were transitions and many occurred at di-pyrimidine sites that are susceptible to ultraviolet (UV) radiation induced mutation. These data suggest that novel germ-line (blood) and somatic (lens) coding SNVs in EPHA2 that are predicted to be functionally deleterious occur in adults over 50 years of age. However, both types of EPHA2 coding variants were present at comparable levels in individuals with or without age-related cataract making simple genotype-phenotype correlations inconclusive.

Germ-line and somatic EPHA2 coding variants in lens aging and cataract

PubMed Central

Bennett, Thomas M.; M’Hamdi, Oussama; Hejtmancik, J. Fielding

2017-01-01

Rare germ-line mutations in the coding regions of the human EPHA2 gene (EPHA2) have been associated with inherited forms of pediatric cataract, whereas, frequent, non-coding, single nucleotide variants (SNVs) have been associated with age-related cataract. Here we sought to determine if germ-line EPHA2 coding SNVs were associated with age-related cataract in a case-control DNA panel (> 50 years) and if somatic EPHA2 coding SNVs were associated with lens aging and/or cataract in a post-mortem lens DNA panel (> 48 years). Micro-fluidic PCR amplification followed by targeted amplicon (exon) next-generation (deep) sequencing of EPHA2 (17-exons) afforded high read-depth coverage (1000x) for > 82% of reads in the cataract case-control panel (161 cases, 64 controls) and > 70% of reads in the post-mortem lens panel (35 clear lens pairs, 22 cataract lens pairs). Novel and reference (known) missense SNVs in EPHA2 that were predicted in silico to be functionally damaging were found in both cases and controls from the age-related cataract panel at variant allele frequencies (VAFs) consistent with germ-line transmission (VAF > 20%). Similarly, both novel and reference missense SNVs in EPHA2 were found in the post-mortem lens panel at VAFs consistent with a somatic origin (VAF > 3%). The majority of SNVs found in the cataract case-control panel and post-mortem lens panel were transitions and many occurred at di-pyrimidine sites that are susceptible to ultraviolet (UV) radiation induced mutation. These data suggest that novel germ-line (blood) and somatic (lens) coding SNVs in EPHA2 that are predicted to be functionally deleterious occur in adults over 50 years of age. However, both types of EPHA2 coding variants were present at comparable levels in individuals with or without age-related cataract making simple genotype-phenotype correlations inconclusive. PMID:29267365

Complete Biallelic Insulation at the H19/Igf2 Imprinting Control Region Position Results in Fetal Growth Retardation and Perinatal Lethality

PubMed Central

Lee, Dong-Hoon; Singh, Purnima; Tsark, Walter M. K.; Szabó, Piroska E.

2010-01-01

Background The H19/Igf2 imprinting control region (ICR) functions as an insulator exclusively in the unmethylated maternal allele, where enhancer-blocking by CTCF protein prevents the interaction between the Igf2 promoter and the distant enhancers. DNA methylation inhibits CTCF binding in the paternal ICR allele. Two copies of the chicken β-globin insulator (ChβGI)2 are capable of substituting for the enhancer blocking function of the ICR. Insulation, however, now also occurs upon paternal inheritance, because unlike the H19 ICR, the (ChβGI)2 does not become methylated in fetal male germ cells. The (ChβGI)2 is a composite insulator, exhibiting enhancer blocking by CTCF and chromatin barrier functions by USF1 and VEZF1. We asked the question whether these barrier proteins protected the (ChβGI)2 sequences from methylation in the male germ line. Methodology/Principal Findings We genetically dissected the ChβGI in the mouse by deleting the binding sites USF1 and VEZF1. The methylation of the mutant versus normal (ChβGI)2 significantly increased from 11% to 32% in perinatal male germ cells, suggesting that the barrier proteins did have a role in protecting the (ChβGI)2 from methylation in the male germ line. Contrary to the H19 ICR, however, the mutant (mChβGI)2 lacked the potential to attain full de novo methylation in the germ line and to maintain methylation in the paternal allele in the soma, where it consequently functioned as a biallelic insulator. Unexpectedly, a stricter enhancer blocking was achieved by CTCF alone than by a combination of the CTCF, USF1 and VEZF1 sites, illustrated by undetectable Igf2 expression upon paternal transmission. Conclusions/Significance In this in vivo model, hypomethylation at the ICR position together with fetal growth retardation mimicked the human Silver-Russell syndrome. Importantly, late fetal/perinatal death occurred arguing that strict biallelic insulation at the H19/Igf2 ICR position is not tolerated in development. PMID:20838620

Development of germ-line-specific CRISPR-Cas9 systems to improve the production of heritable gene modifications in Arabidopsis

PubMed Central

Mao, Yanfei; Zhang, Zhengjing; Feng, Zhengyan; Wei, Pengliang; Zhang, Hui; Botella, José Ramón; Zhu, Jian-Kang

2017-01-01

Summary The Streptococcus-derived CRISPR/Cas9 system is being widely used to perform targeted gene modifications in plants. This customized endonuclease system has two components, the single-guide RNA (sgRNA) for target DNA recognition and the CRISPR-associated protein 9 (Cas9) for DNA cleavage. Ubiquitously expressed CRISPR/Cas9 systems (UC) generate targeted gene modifications with high efficiency but only those produced in reproductive cells are transmitted to the next generation. We report the design and characterization of a germ-line-specific Cas9 system (GSC) for Arabidopsis gene modification in male gametocytes, constructed using a SPOROCYTELESS (SPL) genomic expression cassette. Four loci in two endogenous genes were targeted by both systems for comparative analysis. Mutations generated by the GSC system were rare in T1 plants but were abundant (30%) in the T2 generation. The vast majority (70%) of the T2 mutant population generated using the UC system were chimeras while the newly developed GSC system produced only 29% chimeras, with 70% of the T2 mutants being heterozygous. Analysis of two loci in the T2 population showed that the abundance of heritable gene mutations was 37% higher in the GSC system compared to the UC system and the level of polymorphism of the mutations was also dramatically increased with the GSC system. Two additional systems based on germ-line-specific promoters (pDD45-GT and pLAT52-GT) were also tested, and one of them was capable of generating heritable homozygous T1 mutant plants. Our results suggest that future application of the described GSC system will facilitate the screening for targeted gene modifications, especially lethal mutations in the T2 population. PMID:26360626

Recombinant rabbit leukemia inhibitory factor and rabbit embryonic fibroblasts support the derivation and maintenance of rabbit embryonic stem cells.

PubMed

Xue, Fei; Ma, Yinghong; Chen, Y Eugene; Zhang, Jifeng; Lin, Tzu-An; Chen, Chien-Hong; Lin, Wei-Wen; Roach, Marsha; Ju, Jyh-Cherng; Yang, Lan; Du, Fuliang; Xu, Jie

2012-08-01

The rabbit is a classical experimental animal species. A major limitation in using rabbits for biomedical research is the lack of germ-line-competent rabbit embryonic stem cells (rbESCs). We hypothesized that the use of homologous feeder cells and recombinant rabbit leukemia inhibitory factor (rbLIF) might improve the chance in deriving germ-line-competent rbES cells. In the present study, we established rabbit embryonic fibroblast (REF) feeder layers and synthesized recombinant rbLIF. We derived a total of seven putative rbESC lines, of which two lines (M5 and M23) were from culture Condition I using mouse embryonic fibroblasts (MEFs) as feeders supplemented with human LIF (hLIF) (MEF+hLIF). Another five lines (R4, R9, R15, R21, and R31) were derived from Condition II using REFs as feeder cells supplemented with rbLIF (REF+rbLIF). Similar derivation efficiency was observed between these two conditions (8.7% vs. 10.2%). In a separate experiment with 2×3 factorial design, we examined the effects of feeder cells (MEF vs. REF) and LIFs (mLIF, hLIF vs. rbLIF) on rbESC culture. Both Conditions I and II supported satisfactory rbESC culture, with similar or better population doubling time and colony-forming efficiency than other combinations of feeder cells with LIFs. Rabbit ESCs derived and maintained on both conditions displayed typical ESC characteristics, including ESC pluripotency marker expression (AP, Oct4, Sox2, Nanog, and SSEA4) and gene expression (Oct4, Sox2, Nanog, c-Myc, Klf4, and Dppa5), and the capacity to differentiate into three primary germ layers in vitro. The present work is the first attempt to establish rbESC lines using homologous feeder cells and recombinant rbLIF, by which the rbESCs were derived and maintained normally. These cell lines are unique resources and may facilitate the derivation of germ-line-competent rbESCs.

Germ line transformation of the yellow fever mosquito, Aedes aegypti, mediated by transpositional insertion of a piggyBac vector.

PubMed

Lobo, N F; Hua-Van, A; Li, X; Nolen, B M; Fraser, M J

2002-04-01

Mosquito-vectored diseases such as yellow fever and dengue fever continue to have a substantial impact on human populations world-wide. Novel strategies for control of these mosquito vectored diseases can arise through the development of reliable systems for genetic manipulation of the insect vector. A piggyBac vector marked with the Drosophila melanogaster cinnabar (cn) gene was used to transform the white-eyed khw strain of Aedes aegypti. Microinjection of preblastoderm embryos resulted in four families of cinnabar transformed insects. An overall transformation frequency of 4%, with a range of 0% to as high as 13% for individual experiments, was achieved when using a heat-shock induced transposase providing helper plasmid. Southern hybridizations indicated multiple insertion events in three of four transgenic lines, while the presence of duplicated target TTAA sites at either ends of individual insertions confirmed characteristic piggyBac transposition events in these three transgenic lines. The transgenic phenotype has remained stable for more than twenty generations. The transformations effected using the piggyBac element establish the potential of this element as a germ-line transformation vector for Aedine mosquitoes.

A purified, fermented, extract of Triticum aestivum has lymphomacidal activity mediated via natural killer cell activation

PubMed Central

Barisone, Gustavo A.; O’Donnell, Robert T.; Ma, Yunpeng; Abuhay, Mastewal W.; Lundeberg, Kathleen; Gowda, Sonia

2018-01-01

Non-Hodgkin lymphoma (NHL) affects over 400,000 people in the United States; its incidence increases with age. Treatment options are numerous and expanding, yet efficacy is often limited by toxicity, particularly in the elderly. Nearly 70% patients eventually die of the disease. Many patients explore less toxic alternative therapeutics proposed to boost anti-tumor immunity, despite a paucity of rigorous scientific data. Here we evaluate the lymphomacidal and immunomodulatory activities of a protein fraction isolated from fermented wheat germ. Fermented wheat germ extract was produced by fermenting wheat germ with Saccharomyces cerevisiae. A protein fraction was tested for lymphomacidal activity in vitro using NHL cell lines and in vivo using mouse xenografts. Mechanisms of action were explored in vitro by evaluating apoptosis and cell cycle and in vivo by immunophenotyping and measurement of NK cell activity. Potent lymphomacidal activity was observed in a panel of NHL cell lines and mice bearing NHL xenografts. This activity was not dependent on wheat germ agglutinin or benzoquinones. Fermented wheat germ proteins induced apoptosis in NHL cells, and augmented immune effector mechanisms, as measured by NK cell killing activity, degranulation and production of IFNγ. Fermented wheat germ extract can be easily produced and is efficacious in a human lymphoma xenograft model. The protein fraction is quantifiable and more potent, shows direct pro-apoptotic properties, and enhances immune-mediated tumor eradication. The results presented herein support the novel concept that proteins in fermented wheat germ have direct pro-apoptotic activity on lymphoma cells and augment host immune effector mechanisms. PMID:29304125

Transgenerational Epigenetic Programming of the Embryonic Testis Transcriptome

PubMed Central

Anway, Matthew D.; Rekow, Stephen S.; Skinner, Michael K.

2008-01-01

Embryonic exposure to the endocrine disruptor vinclozolin during gonadal sex determination appears to promote an epigenetic reprogramming of the male germ-line that is associated with transgenerational adult onset disease states. Transgenerational effects on the embryonic day 16 (E16) testis demonstrated reproducible changes in the testis transcriptome for multiple generations (F1-F3). The expression of 196 genes were found to be influenced, with the majority of gene expression being decreased or silenced. Dramatic changes in the gene expression of methyltransferases during gonadal sex determination were observed in the F1 and F2 vinclozolin generation (E16) embryonic testis, but the majority returned to control generation levels by the F3 generation. The most dramatic effects were on the germ-line associated Dnmt3A and Dnmt3L isoforms. Observations demonstrate that an embryonic exposure to vinclozolin appears to promote an epigenetic reprogramming of the male germ-line that correlates with transgenerational alterations in the testis transcriptome in subsequent generations. PMID:18042343

Comparison of a teratogenic transcriptome-based predictive test based on human embryonic versus inducible pluripotent stem cells.

PubMed

Shinde, Vaibhav; Perumal Srinivasan, Sureshkumar; Henry, Margit; Rotshteyn, Tamara; Hescheler, Jürgen; Rahnenführer, Jörg; Grinberg, Marianna; Meisig, Johannes; Blüthgen, Nils; Waldmann, Tanja; Leist, Marcel; Hengstler, Jan Georg; Sachinidis, Agapios

2016-12-30

Human embryonic stem cells (hESCs) partially recapitulate early embryonic three germ layer development, allowing testing of potential teratogenic hazards. Because use of hESCs is ethically debated, we investigated the potential for human induced pluripotent stem cells (hiPSCs) to replace hESCs in such tests. Three cell lines, comprising hiPSCs (foreskin and IMR90) and hESCs (H9) were differentiated for 14 days. Their transcriptome profiles were obtained on day 0 and day 14 and analyzed by comprehensive bioinformatics tools. The transcriptomes on day 14 showed that more than 70% of the "developmental genes" (regulated genes with > 2-fold change on day 14 compared to day 0) exhibited variability among cell lines. The developmental genes belonging to all three cell lines captured biological processes and KEGG pathways related to all three germ layer embryonic development. In addition, transcriptome profiles were obtained after 14 days of exposure to teratogenic valproic acid (VPA) during differentiation. Although the differentially regulated genes between treated and untreated samples showed more than 90% variability among cell lines, VPA clearly antagonized the expression of developmental genes in all cell lines: suppressing upregulated developmental genes, while inducing downregulated ones. To quantify VPA-disturbed development based on developmental genes, we estimated the "developmental potency" (D p ) and "developmental index" (D i ). Despite differences in genes deregulated by VPA, uniform D i values were obtained for all three cell lines. Given that the D i values for VPA were similar for hESCs and hiPSCs, D i can be used for robust hazard identification, irrespective of whether hESCs or hiPSCs are used in the test systems.

Mitotic Arrest in Teratoma Susceptible Fetal Male Germ Cells

PubMed Central

Western, Patrick S.; Ralli, Rachael A.; Wakeling, Stephanie I.; Lo, Camden; van den Bergen, Jocelyn A.; Miles, Denise C.; Sinclair, Andrew H.

2011-01-01

Formation of germ cell derived teratomas occurs in mice of the 129/SvJ strain, but not in C57Bl/6 inbred or CD1 outbred mice. Despite this, there have been few comparative studies aimed at determining the similarities and differences between teratoma susceptible and non-susceptible mouse strains. This study examines the entry of fetal germ cells into the male pathway and mitotic arrest in 129T2/SvJ mice. We find that although the entry of fetal germ cells into mitotic arrest is similar between 129T2/SvJ, C57Bl/6 and CD1 mice, there were significant differences in the size and germ cell content of the testis cords in these strains. In 129T2/SvJ mice germ cell mitotic arrest involves upregulation of p27KIP1, p15INK4B, activation of RB, the expression of male germ cell differentiation markers NANOS2, DNMT3L and MILI and repression of the pluripotency network. The germ-line markers DPPA2 and DPPA4 show reciprocal repression and upregulation, respectively, while FGFR3 is substantially enriched in the nucleus of differentiating male germ cells. Further understanding of fetal male germ cell differentiation promises to provide insight into disorders of the testis and germ cell lineage, such as testis tumour formation and infertility. PMID:21674058

Analysis of the cytoskeleton organization and its possible functions in male earthworm germ-line cysts equipped with a cytophore.

PubMed

Małota, Karol; Świątek, Piotr

2016-10-01

We studied the organization of F-actin and the microtubular cytoskeleton in male germ-line cysts in the seminal vesicles of the earthworm Dendrobaena veneta using light, fluorescent and electron microscopy along with both chemically fixed tissue and life cell imaging. Additionally, in order to follow the functioning of the cytoskeleton, we incubated the cysts in colchicine, nocodazole, cytochalasin D and latrunculin A. The male germ-line cells of D. veneta are interconnected via stable intercellular bridges (IB), and form syncytial cysts. Each germ cell has only one IB that connects it to the anuclear central cytoplasmic mass, the cytophore. During the studies, we analyzed the cytoskeleton in spermatogonial, spermatocytic and spermatid cysts. F-actin was detected in the cortical cytoplasm and forms distinct rings in the IBs. The arrangement of the microtubules changed dynamically during spermatogenesis. The microtubules are distributed evenly in whole spermatogonial and spermatocytic cysts; however, they primarily accumulate within the IBs in spermatogonia. In early spermatids, microtubules pass through the IBs and are present in whole cysts. During spermatid elongation, the microtubules form a manchette while they are absent in the cytophore and in the IBs. Use of cytoskeletal drugs did not alter the general morphology of the cysts. Detectable effects-the occurrence of nuclei in the late spermatids and manchette fragments in the cytophore-were observed only after incubation in nocodazole. Our results suggest that the microtubules are responsible for cytoplasmic/organelle transfer between the germ cells and the cytophore during spermatogenesis and for the positioning of the spermatid nuclei.

Derivation of porcine pluripotent stem cells for biomedical research.

PubMed

Shiue, Yow-Ling; Yang, Jenn-Rong; Liao, Yu-Jing; Kuo, Ting-Yung; Liao, Chia-Hsin; Kang, Ching-Hsun; Tai, Chein; Anderson, Gary B; Chen, Lih-Ren

2016-07-01

Pluripotent stem cells including embryonic stem cells (ESCs), embryonic germ cells (EGCs), and induced pluripotent stem cells (iPSCs) are capable of self-renew and limitlessly proliferating in vitro with undifferentiated characteristics. They are able to differentiate in vitro, spontaneously or responding to suitable signals, into cells of all three primary germ layers. Consequently, these pluripotent stem cells will be valuable sources for cell replacement therapy in numerous disorders. However, the promise of human ESCs and EGCs is cramped by the ethical argument about destroying embryos and fetuses for cell line creation. Moreover, there are still carcinogenic risks existing toward the goal of clinical application for human ESCs, EGCs, and iPSCs. Therefore, a suitable animal model for stem cell research will benefit the further development of human stem cell technology. The pigs, on the basis of their similarity in anatomy, immunology, physiology, and biochemical properties, have been wide used as model animals in the study of various human diseases. The development of porcine pluripotent stem cell lines will hold the opportunity to provide an excellent material for human counterpart to the transplantation in biomedical research and further development of cell-based therapeutic strategy. Copyright © 2016 Elsevier Inc. All rights reserved.

Seeking perfection: a Kantian look at human genetic engineering.

PubMed

Gunderson, Martin

2007-01-01

It is tempting to argue that Kantian moral philosophy justifies prohibiting both human germ-line genetic engineering and non-therapeutic genetic engineering because they fail to respect human dignity. There are, however, good reasons for resisting this temptation. In fact, Kant's moral philosophy provides reasons that support genetic engineering-even germ-line and non-therapeutic. This is true of Kant's imperfect duties to seek one's own perfection and the happiness of others. It is also true of the categorical imperative. Kant's moral philosophy does, however, provide limits to justifiable genetic engineering.

CD34+ Testicular Stromal Cells Support Long-Term Expansion of Embryonic and Adult Stem and Progenitor Cells

PubMed Central

Kim, Jiyeon; Seandel, Marco; Falciatori, Ilaria; Wen, Duancheng; Rafii, Shahin

2010-01-01

Stem cells reside in specialized microenvironments created by supporting stromal cells that orchestrate self-renewal and lineage-specific differentiation. However, the precise identity of the cellular and molecular pathways that support self-renewal of stem cells is not known. For example, long-term culture of prototypical stem cells, such as adult spermatogonial stem and progenitor cells (SPCs), in vitro has been impeded by the lack of an optimal stromal cell line that initiates and sustains proliferation of these cells. Indeed, current methods, including the use of mouse embryonic fibroblasts (MEFs), have not been efficient and have generally led to inconsistent results. Here, we report the establishment of a novel CD34-positive cell line, referred to as JK1, derived from mouse testicular stromal cells that not only facilitated long-term SPC culture but also allowed faithful generation of SPCs and multipotent stem cells. SPCs generated on JK1 maintained key features of germ line stem cells, including expression of PLZF, DAZL, and GCNA. Furthermore, these feeders also promoted the long-term cultivation of other types of primitive cells including multi-potent adult spermatogonial-derived stem cells, pluripotent murine embryonic stem cells, and embryonic germ cells derived from primordial germ cells. Stem cells could be passaged serially and still maintained expression of characteristic markers such as OCT4 and NANOG in vitro, as well as the ability to generate all three germ layers in vivo. These results indicate that the JK1 cell line is capable of promoting long-term culture of primitive cells. As such, this cell line allows for identification of stromal-derived factors that support long-term proliferation of various types of stem cells and constitutes a convenient alternative to other types of feeder layers. PMID:18669907

De novo piRNA cluster formation in the Drosophila germ line triggered by transgenes containing a transcribed transposon fragment.

PubMed

Olovnikov, Ivan; Ryazansky, Sergei; Shpiz, Sergey; Lavrov, Sergey; Abramov, Yuri; Vaury, Chantal; Jensen, Silke; Kalmykova, Alla

2013-06-01

PIWI-interacting RNAs (piRNAs) provide defence against transposable element (TE) expansion in the germ line of metazoans. piRNAs are processed from the transcripts encoded by specialized heterochromatic clusters enriched in damaged copies of transposons. How these regions are recognized as a source of piRNAs is still elusive. The aim of this study is to determine how transgenes that contain a fragment of the Long Interspersed Nuclear Elements (LINE)-like I transposon lead to an acquired TE resistance in Drosophila. We show that such transgenes, being inserted in unique euchromatic regions that normally do not produce small RNAs, become de novo bidirectional piRNA clusters that silence I-element activity in the germ line. Strikingly, small RNAs of both polarities are generated from the entire transgene and flanking genomic sequences--not only from the transposon fragment. Chromatin immunoprecipitation analysis shows that in ovaries, the trimethylated histone 3 lysine 9 (H3K9me3) mark associates with transgenes producing piRNAs. We show that transgene-derived hsp70 piRNAs stimulate in trans cleavage of cognate endogenous transcripts with subsequent processing of the non-homologous parts of these transcripts into piRNAs.

Use of Stirred Suspension Bioreactors for Male Germ Cell Enrichment.

PubMed

Sakib, Sadman; Dores, Camila; Rancourt, Derrick; Dobrinski, Ina

2016-01-01

Spermatogenesis is a stem cell based system. Both therapeutic and biomedical research applications of spermatogonial stem cells require a large number of cells. However, there are only few germ line stem cells in the testis, contained in the fraction of undifferentiated spermatogonia. The lack of specific markers makes it difficult to isolate these cells. The long term maintenance and proliferation of nonrodent germ cells in culture has so far been met with limited success, partially due to the lack of highly enriched starting populations. Differential plating, which depends on the differential adhesion properties of testicular somatic and germ cells to tissue culture dishes, has been the method of choice for germ cell enrichment, especially for nonrodent germ cells. However, for large animals, this process becomes labor intensive and increases variability due to the need for extensive handling. Here, we describe the use of stirred suspension bioreactors, as a novel system for enriching undifferentiated germ cells from 1-week-old pigs. This method capitalizes on the adherent properties of somatic cells within a controlled environment, thus promoting the enrichment of progenitor cells with minimal handling and variability.

Human DAZL, DAZ and BOULE genes modulate primordial germ cell and haploid gamete formation

PubMed Central

Kee, Kehkooi; Angeles, Vanessa T; Flores, Martha; Nguyen, Ha Nam; Pera, Renee A Reijo

2009-01-01

The leading cause of infertility in men and women is quantitative and qualitative defects in human germ cell (oocyte and sperm) development. Yet, it has not been possible to examine the unique developmental genetics of human germ cell formation and differentiation due to inaccessibility of germ cells during fetal development. Although several studies have shown that germ cells can be differentiated from mouse and human embryonic stem cells, human germ cells differentiated in these studies generally did not develop beyond the earliest stages1-8. Here we used a germ cell reporter to quantitate and isolate primordial germ cells derived from both male and female hESCs. Then, by silencing and overexpressing genes that encode germ cell-specific cytoplasmic RNA-binding proteins (not transcription factors), we modulated human germ cell formation and developmental progression. We observed that human DAZL (Deleted in AZoospermia-Like) functions in primordial germ cell formation, whereas closely-related genes, DAZ and BOULE, promote later stages of meiosis and development of haploid gametes. These results are significant to the generation of gametes for future basic science and potential clinical applications. PMID:19865085

One small edit for humans, one giant edit for humankind? Points and questions to consider for a responsible way forward for gene editing in humans.

PubMed

Howard, Heidi C; van El, Carla G; Forzano, Francesca; Radojkovic, Dragica; Rial-Sebbag, Emmanuelle; de Wert, Guido; Borry, Pascal; Cornel, Martina C

2018-01-01

Gene editing, which allows for specific location(s) in the genome to be targeted and altered by deleting, adding or substituting nucleotides, is currently the subject of important academic and policy discussions. With the advent of efficient tools, such as CRISPR-Cas9, the plausibility of using gene editing safely in humans for either somatic or germ line gene editing is being considered seriously. Beyond safety issues, somatic gene editing in humans does raise ethical, legal and social issues (ELSI), however, it is suggested to be less challenging to existing ethical and legal frameworks; indeed somatic gene editing is already applied in (pre-) clinical trials. In contrast, the notion of altering the germ line or embryo such that alterations could be heritable in humans raises a large number of ELSI; it is currently debated whether it should even be allowed in the context of basic research. Even greater ELSI debates address the potential use of germ line or embryo gene editing for clinical purposes, which, at the moment is not being conducted and is prohibited in several jurisdictions. In the context of these ongoing debates surrounding gene editing, we present herein guidance to further discussion and investigation by highlighting three crucial areas that merit the most attention, time and resources at this stage in the responsible development and use of gene editing technologies: (1) conducting careful scientific research and disseminating results to build a solid evidence base; (2) conducting ethical, legal and social issues research; and (3) conducting meaningful stakeholder engagement, education and dialogue.

Constitutive activation of B-Raf in the mouse germ line provides a model for human cardio-facio-cutaneous syndrome.

PubMed

Urosevic, Jelena; Sauzeau, Vincent; Soto-Montenegro, María L; Reig, Santiago; Desco, Manuel; Wright, Emma M Burkitt; Cañamero, Marta; Mulero, Francisca; Ortega, Sagrario; Bustelo, Xosé R; Barbacid, Mariano

2011-03-22

RASopathies are a class of developmental syndromes that result from congenital mutations in key elements of the RAS/RAF/MEK signaling pathway. A well-recognized RASopathy is the cardio-facio-cutaneous (CFC) syndrome characterized by a distinctive facial appearance, heart defects, and mental retardation. Clinically diagnosed CFC patients carry germ-line mutations in four different genes, B-RAF, MEK1, MEK2, and K-RAS. B-RAF is by far the most commonly mutated locus, displaying mutations that most often result in constitutive activation of the B-RAF kinase. Here, we describe a mouse model for CFC generated by germ-line expression of a B-RafLSLV600E allele. This targeted allele allows low levels of expression of B-RafV600E, a constitutively active B-Raf kinase first identified in human melanoma. B-Raf+/LSLV600E mice are viable and display several of the characteristic features observed in CFC patients, including reduced life span, small size, facial dysmorphism, cardiomegaly, and epileptic seizures. These mice also show up-regulation of specific catecholamines and cataracts, two features detected in a low percentage of CFC patients. In addition, B-Raf+/LSLV600E mice develop neuroendocrine tumors, a pathology not observed in CFC patients. These mice may provide a means of better understanding the pathophysiology of at least some of the clinical features present in CFC patients. Moreover, they may serve as a tool to evaluate the potential therapeutic efficacy of B-RAF inhibitors and establish the precise window at which they could be effective against this congenital syndrome.

Very Few Substitutions in a Germ Line Antibody Are Required To Initiate Significant Domain Exchange ▿

PubMed Central

Huber, Michael; Le, Khoa M.; Doores, Katie J.; Fulton, Zara; Stanfield, Robyn L.; Wilson, Ian A.; Burton, Dennis R.

2010-01-01

2G12 is a broadly neutralizing anti-HIV-1 monoclonal human IgG1 antibody reactive with a high-mannose glycan cluster on the surface of glycoprotein gp120. A key feature of this very highly mutated antibody is domain exchange of the heavy-chain variable region (VH) with the VH of the adjacent Fab of the same immunoglobulin, which assembles a multivalent binding interface composed of two primary binding sites in close proximity. A non-germ line-encoded proline in the elbow between VH and CH1 and an extensive network of hydrophobic interactions in the VH/VH′ interface have been proposed to be crucial for domain exchange. To investigate the origins of domain exchange, a germ line version of 2G12 that behaves as a conventional antibody was engineered. Substitution of 5 to 7 residues for those of the wild type produced a significant fraction of domain-exchanged molecules, with no evidence of equilibrium between domain-exchanged and conventional forms. Two substitutions not previously implicated, AH14 and EH75, are the most crucial for domain exchange, together with IH19 at the VH/VH′ interface and PH113 in the elbow region. Structural modeling gave clues as to why these residues are essential for domain exchange. The demonstration that domain exchange can be initiated by a small number of substitutions in a germ line antibody suggests that the evolution of a domain-exchanged antibody response in vivo may be more readily achieved than considered to date. PMID:20702640

Identification of prostate cancer modifier pathways using parental strain expression mapping

PubMed Central

Xu, Qing; Majumder, Pradip K.; Ross, Kenneth; Shim, Yeonju; Golub, Todd R.; Loda, Massimo; Sellers, William R.

2007-01-01

Inherited genetic risk factors play an important role in cancer. However, other than the Mendelian fashion cancer susceptibility genes found in familial cancer syndromes, little is known about risk modifiers that control individual susceptibility. Here we developed a strategy, parental strain expression mapping, that utilizes the homogeneity of inbred mice and genome-wide mRNA expression analyses to directly identify candidate germ-line modifier genes and pathways underlying phenotypic differences among murine strains exposed to transgenic activation of AKT1. We identified multiple candidate modifier pathways and, specifically, the glycolysis pathway as a candidate negative modulator of AKT1-induced proliferation. In keeping with the findings in the murine models, in multiple human prostate expression data set, we found that enrichment of glycolysis pathways in normal tissues was associated with decreased rates of cancer recurrence after prostatectomy. Together, these data suggest that parental strain expression mapping can directly identify germ-line modifier pathways of relevance to human disease. PMID:17978178

Disrupting the male germ line to find infertility and contraception targets.

PubMed

Archambeault, Denise R; Matzuk, Martin M

2014-05-01

Genetically-manipulated mouse models have become indispensible for broadening our understanding of genes and pathways related to male germ cell development. Until suitable in vitro systems for studying spermatogenesis are perfected, in vivo models will remain the gold standard for inquiry into testicular function. Here, we discuss exciting advances that are allowing researchers faster, easier, and more customizable access to their mouse models of interest. Specifically, the trans-NIH Knockout Mouse Project (KOMP) is working to generate knockout mouse models of every gene in the mouse genome. The related Knockout Mouse Phenotyping Program (KOMP2) is performing systematic phenotypic analysis of this genome-wide collection of knockout mice, including fertility screening. Together, these programs will not only uncover new genes involved in male germ cell development but also provide the research community with the mouse models necessary for further investigations. In addition to KOMP/KOMP2, another promising development in the field of mouse models is the advent of CRISPR (clustered regularly interspaced short palindromic repeat)-Cas technology. Utilizing 20 nucleotide guide sequences, CRISPR/Cas has the potential to introduce sequence-specific insertions, deletions, and point mutations to produce null, conditional, activated, or reporter-tagged alleles. CRISPR/Cas can also successfully target multiple genes in a single experimental step, forgoing the multiple generations of breeding traditionally required to produce mouse models with deletions, insertions, or mutations in multiple genes. In addition, CRISPR/Cas can be used to create mouse models carrying variants identical to those identified in infertile human patients, providing the opportunity to explore the effects of such mutations in an in vivo system. Both the KOMP/KOMP2 projects and the CRISPR/Cas system provide powerful, accessible genetic approaches to the study of male germ cell development in the mouse. A more complete understanding of male germ cell biology is critical for the identification of novel targets for potential non-hormonal contraceptive intervention. Copyright © 2014. Published by Elsevier Masson SAS.

Intermolecular Interactions of Homologs of Germ Plasm Components in Mammalian Germ Cells

PubMed Central

Fox, Mark S.; Clark, Amander T.; El Majdoubi, Mohammed; Vigne, Jean-Louis; Urano, Jun; Hostetler, Chris E.; Griswold, Michael D.; Weiner, Richard I.; Pera, Renee A. Reijo

2007-01-01

In some species such as flies, worms, frogs, and fish the key to forming and maintaining early germ cell populations is the assembly of germ plasm, microscopically-distinct egg cytoplasm that is rich in RNAs, RNA-binding proteins and ribosomes. Cells which inherit germ plasm are destined for the germ cell lineage. In contrast, in mammals, germ cells are formed and maintained later in development as a result of inductive signaling from one embryonic cell type to another. Research advances, using complementary approaches, including identification of key signaling factors that act during the initial stages of germ cell development, differentiation of germ cells in vitro from mouse and human embryonic stem cells and the demonstration, that homologs of germ plasm components are conserved in mammals, have shed light on key elements in the early development of mammalian germ cells. Here, we use FRET (Fluorescence Resonance Energy Transfer) to demonstrate that living mammalian germ cells possess specific RNA/protein complexes that contain germ plasm homologs, beginning in the earliest stages of development examined. Moreover, we demonstrate that although both human and mouse germ cells and embryonic stem cells express the same proteins, germ cell specific protein/protein interactions distinguish germ cells from precursor embryonic stem cells in vitro; interactions also determine sub-cellular localization of complex components. Finally, we suggest that assembly of similar protein complexes may be central to differentiation of diverse cell lineages and provide useful diagnostic tools for isolation of specific cell types from the assorted types differentiated from embryonic stem cells. PMID:16996493

Colleges Put the Squeeze on Germs

ERIC Educational Resources Information Center

Sander, Libby

2008-01-01

A spirited campaign to promote "hand hygiene" is under way at the University of Central Florida Orlando campus, and the urinal toter, known as UCF 5th Guy, is its front line. Like their counterparts at many other institutions, health officials at Central Florida want students to think about the germs that lurk on their hands. And then…

Extraordinary genome stability in the ciliate Paramecium tetraurelia

PubMed Central

Sung, Way; Tucker, Abraham E.; Doak, Thomas G.; Choi, Eunjin; Thomas, W. Kelley; Lynch, Michael

2012-01-01

Mutation plays a central role in all evolutionary processes and is also the basis of genetic disorders. Established base-substitution mutation rates in eukaryotes range between ∼5 × 10−10 and 5 × 10−8 per site per generation, but here we report a genome-wide estimate for Paramecium tetraurelia that is more than an order of magnitude lower than any previous eukaryotic estimate. Nevertheless, when the mutation rate per cell division is extrapolated to the length of the sexual cycle for this protist, the measure obtained is comparable to that for multicellular species with similar genome sizes. Because Paramecium has a transcriptionally silent germ-line nucleus, these results are consistent with the hypothesis that natural selection operates on the cumulative germ-line replication fidelity per episode of somatic gene expression, with the germ-line mutation rate per cell division evolving downward to the lower barrier imposed by random genetic drift. We observe ciliate-specific modifications of widely conserved amino acid sites in DNA polymerases as one potential explanation for unusually high levels of replication fidelity. PMID:23129619

Is Mitochondrial Donation Germ-Line Gene Therapy? Classifications and Ethical Implications.

PubMed

Newson, Ainsley J; Wrigley, Anthony

2017-01-01

The classification of techniques used in mitochondrial donation, including their role as purported germ-line gene therapies, is far from clear. These techniques exhibit characteristics typical of a variety of classifications that have been used in both scientific and bioethics scholarship. This raises two connected questions, which we address in this paper: (i) how should we classify mitochondrial donation techniques?; and (ii) what ethical implications surround such a classification? First, we outline how methods of genetic intervention, such as germ-line gene therapy, are typically defined or classified. We then consider whether techniques of mitochondrial donation fit into these, whether they might do so with some refinement of these categories, or whether they require some other approach to classification. To answer the second question, we discuss the relationship between classification and several key ethical issues arising from mitochondrial donation. We conclude that the properties characteristic of mitochondrial inheritance mean that most mitochondrial donation techniques belong to a new sub-class of genetic modification, which we call 'conditionally inheritable genomic modification' (CIGM). © 2017 John Wiley & Sons Ltd.

Autoantibodies against Leydig cells in patients after spermatic cord torsion.

PubMed Central

Zanchetta, R; Mastrogiacomo, I; Graziotti, P; Foresta, C; Betterle, C

1984-01-01

This study is aimed at searching for the presence of circulating antibodies against frozen sections of human testis, ovary and trophoblast in patients that had spermatic cord torsion. Sixty-eight sera samples were studied. Nine patients (13.2%) were positive for organ specific anti-testis autoantibodies. Six patients were positive for antibodies against Leydig cells: five were positive only with the indirect immunofluorescence technique of complement fixing (ITT/CF), the sixth patient was positive only with the indirect immunofluorescence technique (ITT). The other three patients were positive for antibodies against germ line cells: two patients were positive with both techniques, the third was positive only with indirect immunofluorescence technique. Eight of these patients were negative for antibodies against adrenal cortex while only one case was positive with indirect immunofluorescence technique both on adrenal cortex and Leydig cells. Human lyophilized testis absorbed the reactive antibodies against Leydig cells and germ line cells, while adrenal cortex and lyophilized testosterone were ineffective. This study shows the identification of a specific antibody against Leydig cells and germ line cells in patients after spermatic cord torsion. PMID:6362937

A mitotic kinase scaffold depleted in testicular seminomas impacts spindle orientation in germ line stem cells

PubMed Central

Hehnly, Heidi; Canton, David; Bucko, Paula; Langeberg, Lorene K; Ogier, Leah; Gelman, Irwin; Santana, L Fernando; Wordeman, Linda; Scott, John D

2015-01-01

Correct orientation of the mitotic spindle in stem cells underlies organogenesis. Spindle abnormalities correlate with cancer progression in germ line-derived tumors. We discover a macromolecular complex between the scaffolding protein Gravin/AKAP12 and the mitotic kinases, Aurora A and Plk1, that is down regulated in human seminoma. Depletion of Gravin correlates with an increased mitotic index and disorganization of seminiferous tubules. Biochemical, super-resolution imaging, and enzymology approaches establish that this Gravin scaffold accumulates at the mother spindle pole during metaphase. Manipulating elements of the Gravin-Aurora A-Plk1 axis prompts mitotic delay and prevents appropriate assembly of astral microtubules to promote spindle misorientation. These pathological responses are conserved in seminiferous tubules from Gravin−/− mice where an overabundance of Oct3/4 positive germ line stem cells displays randomized orientation of mitotic spindles. Thus, we propose that Gravin-mediated recruitment of Aurora A and Plk1 to the mother (oldest) spindle pole contributes to the fidelity of symmetric cell division. DOI: http://dx.doi.org/10.7554/eLife.09384.001 PMID:26406118

Immunoglobulin kappa light chain gene promoter and enhancer are not responsible for B-cell restricted gene rearrangement.

PubMed Central

Goodhardt, M; Babinet, C; Lutfalla, G; Kallenbach, S; Cavelier, P; Rougeon, F

1989-01-01

We have produced transgenic mice which synthesize chimeric mouse-rabbit immunoglobulin (Ig) kappa light chains following in vivo recombination of an injected unrearranged kappa gene. The exogenous gene construct contained a mouse germ-line kappa variable (V kappa) gene segment, the mouse germ-line joining (J kappa) locus including the enhancer, and the rabbit b9 constant (C kappa) region. A high level of V-J recombination of the kappa transgene was observed in spleen of the transgenic mice. Surprisingly, a particularly high degree of variability in the exact site of recombination and the presence of non germ-line encoded nucleotides (N-regions) were found at the V-J junction of the rearranged kappa transgene. Furthermore, unlike endogenous kappa genes, rearrangement of the exogenous gene occurred in T-cells of the transgenic mice. These results show that additional sequences, other than the heptamer-nonamer signal sequences and the promoter and enhancer elements, are required to obtain stage- and lineage- specific regulation of Ig kappa light chain gene rearrangement in vivo. Images PMID:2508061

Alu repeated DNAs are differentially methylated in primate germ cells.

PubMed Central

Rubin, C M; VandeVoort, C A; Teplitz, R L; Schmid, C W

1994-01-01

A significant fraction of Alu repeats in human sperm DNA, previously found to be unmethylated, is nearly completely methylated in DNA from many somatic tissues. A similar fraction of unmethylated Alus is observed here in sperm DNA from rhesus monkey. However, Alus are almost completely methylated at the restriction sites tested in monkey follicular oocyte DNA. The Alu methylation patterns in mature male and female monkey germ cells are consistent with Alu methylation in human germ cell tumors. Alu sequences are hypomethylated in seminoma DNAs and more methylated in a human ovarian dysgerminoma. These results contrast with methylation patterns reported for germ cell single-copy, CpG island, satellite, and L1 sequences. The function of Alu repeats is not known, but differential methylation of Alu repeats in the male and female germ lines suggests that they may serve as markers for genomic imprinting or in maintaining differences in male and female meiosis. Images PMID:7800508

Recombinant Rabbit Leukemia Inhibitory Factor and Rabbit Embryonic Fibroblasts Support the Derivation and Maintenance of Rabbit Embryonic Stem Cells

PubMed Central

Xue, Fei; Ma, Yinghong; Chen, Y. Eugene; Zhang, Jifeng; Lin, Tzu-An; Chen, Chien-Hong; Lin, Wei-Wen; Roach, Marsha; Ju, Jyh-Cherng; Yang, Lan; Du, Fuliang

2012-01-01

Abstract The rabbit is a classical experimental animal species. A major limitation in using rabbits for biomedical research is the lack of germ-line-competent rabbit embryonic stem cells (rbESCs). We hypothesized that the use of homologous feeder cells and recombinant rabbit leukemia inhibitory factor (rbLIF) might improve the chance in deriving germ-line-competent rbES cells. In the present study, we established rabbit embryonic fibroblast (REF) feeder layers and synthesized recombinant rbLIF. We derived a total of seven putative rbESC lines, of which two lines (M5 and M23) were from culture Condition I using mouse embryonic fibroblasts (MEFs) as feeders supplemented with human LIF (hLIF) (MEF+hLIF). Another five lines (R4, R9, R15, R21, and R31) were derived from Condition II using REFs as feeder cells supplemented with rbLIF (REF+rbLIF). Similar derivation efficiency was observed between these two conditions (8.7% vs. 10.2%). In a separate experiment with 2×3 factorial design, we examined the effects of feeder cells (MEF vs. REF) and LIFs (mLIF, hLIF vs. rbLIF) on rbESC culture. Both Conditions I and II supported satisfactory rbESC culture, with similar or better population doubling time and colony-forming efficiency than other combinations of feeder cells with LIFs. Rabbit ESCs derived and maintained on both conditions displayed typical ESC characteristics, including ESC pluripotency marker expression (AP, Oct4, Sox2, Nanog, and SSEA4) and gene expression (Oct4, Sox2, Nanog, c-Myc, Klf4, and Dppa5), and the capacity to differentiate into three primary germ layers in vitro. The present work is the first attempt to establish rbESC lines using homologous feeder cells and recombinant rbLIF, by which the rbESCs were derived and maintained normally. These cell lines are unique resources and may facilitate the derivation of germ-line-competent rbESCs. PMID:22775411

Germ line genome editing in clinics: the approaches, objectives and global society

PubMed Central

2017-01-01

Genome editing allows for the versatile genetic modification of somatic cells, germ cells and embryos. In particular, CRISPR/Cas9 is worldwide used in biomedical research. Although the first report on Cas9-mediated gene modification in human embryos focused on the prevention of a genetic disease in offspring, it raised profound ethical and social concerns over the safety of subsequent generations and the potential misuse of genome editing for human enhancement. The present article considers germ line genome editing approaches from various clinical and ethical viewpoints and explores its objectives. The risks and benefits of the following three likely objectives are assessed: the prevention of monogenic diseases, personalized assisted reproductive technology (ART) and genetic enhancement. Although genetic enhancement should be avoided, the international regulatory landscape suggests the inevitability of this misuse at ART centers. Under these circumstances, possible regulatory responses and the potential roles of public dialogue are discussed. PMID:26615180

Glial cell line-derived neurotrophic factor and endothelial cells promote self-renewal of rabbit germ cells with spermatogonial stem cell properties.

PubMed

Kubota, Hiroshi; Wu, Xin; Goodyear, Shaun M; Avarbock, Mary R; Brinster, Ralph L

2011-08-01

Previous studies suggest that exogenous factors crucial for spermatogonial stem cell (SSC) self-renewal are conserved among several mammalian species. Since glial cell line-derived neurotrophic factor (GDNF) and fibroblast growth factor 2 (FGF2) are critical for rodent SSC self-renewal, we hypothesized that they might promote self-renewal of nonrodent SSCs. Therefore, we cultured testicular germ cells from prepubertal rabbits in the presence of GDNF and FGF2 and found they proliferated indefinitely as cellular clumps that displayed characteristics previously identified for rodent SSCs. The rabbit germ cells could not be maintained on mouse embryonic fibroblast (STO) feeders that support rodent SSC self-renewal in vitro but were rather supported on mouse yolk sac-derived endothelial cell (C166) feeder layers. Proliferation of rabbit germ cells was dependent on GDNF. Of critical importance was that clump-forming rabbit germ cells colonized seminiferous tubules of immunodeficient mice, proliferated for at least 6 mo, while retaining an SSC phenotype in the testes of recipient mice, indicating that they were rabbit SSCs. This study demonstrates that GDNF is a mitogenic factor promoting self-renewal that is conserved between rodent and rabbit SSCs; with an evolutionary separation of ∼ 60 million years. These findings provide a foundation to study the mechanisms governing SSC self-renewal in nonrodent species.

Effect of Removal of Spermatogonial Stem Cells (SSCs) from In Vitro Culture on Gene Expression of Niche Factors in Bovine

PubMed Central

Akbarinejad, Vahid; Tajik, Parviz; Movahedin, Mansoureh; Youssefi, Reza

2016-01-01

Background: Niche cells, regulating Spermatogonial Stem Cells (SSCs) fate are believed to have a reciprocal communication with SSCs. The present study was conducted to evaluate the effect of SSC elimination on the gene expression of Glial cell line-Derived Neurotrophic Factor (GDNF), Fibroblast Growth Factor 2 (FGF2) and Kit Ligand (KITLG), which are the main growth factors regulating SSCs development and secreted by niche cells, primarily Sertoli cells. Methods: Following isolation, bovine testicular cells were cultured for 12 days on extracellular matrix-coated plates. In the germ cell-removed group, the SSCs were removed from the in vitro culture using differential plating; however, in the control group, no intervention in the culture was performed. Colony formation of SSCs was evaluated using an inverted microscope. The gene expression of growth factors and spermatogonia markers were assessed using quantitative real time PCR. Results: SSCs colonies were developed in the control group but they were rarely observed in the germ cell-removed group; moreover, the expression of spermatogonia markers was detected in the control group while it was not observed in the germ cell-removed group, substantiating the success of SSCs removal. The expression of Gdnf and Fgf2 was greater in the germ cell-removed than control group (p<0.05), whereas the expression of Kitlg was lower in the germ cell-removed than control group (p< 0.05). Conclusion: In conclusion, the results revealed that niche cells respond to SSCs removal by upregulation of GDNF and FGF2, and downregulation of KITLG in order to stimulate self-renewal and arrest differentiation. PMID:27563426

Expression of the Argonaute protein PiwiL2 and piRNAs in adult mouse mesenchymal stem cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Qiuling; Ma, Qi; Shehadeh, Lina A.

Piwi (P-element-induced wimpy testis) first discovered in Drosophila is a member of the Argonaute family of micro-RNA binding proteins with essential roles in germ-cell development. The murine homologue of PiwiL2, also known as Mili is selectively expressed in the testes, and mice bearing targeted mutations of the PiwiL2 gene are male-sterile. PiwiL2 proteins are thought to protect the germ line genome by suppressing retrotransposons, stabilizing heterochromatin structure, and regulating target genes during meiosis and mitosis. Here, we report that PiwiL2 and associated piRNAs (piRs) may play similar roles in adult mouse mesenchymal stem cells. We found that PiwiL2 is expressedmore » in the cytoplasm of metaphase mesenchymal stem cells from the bone marrow of adult and aged mice. Knockdown of PiwiL2 with a specific siRNA enhanced cell proliferation, significantly increased the number of cells in G1/S and G2/M cell cycle phases and was associated with increased expression of cell cycle genes CCND1, CDK8, microtubule regulation genes, and decreased expression of tumor suppressors Cables 1, LATS, and Cxxc4. The results suggest broader roles for Piwi in genome surveillance beyond the germ line and a possible role in regulating the cell cycle of mesenchymal stem cells.« less

Radiation-induced transgenerational instability.

PubMed

Dubrova, Yuri E

2003-10-13

To date, the analysis of mutation induction has provided an irrefutable evidence for an elevated germline mutation rate in the parents directly exposed to ionizing radiation and a number of chemical mutagens. However, the results of numerous publications suggest that radiation may also have an indirect effect on genome stability, which is transmitted through the germ line of irradiated parents to their offspring. This review describes the phenomenon of transgenerational instability and focuses on the data showing increased cancer incidence and elevated mutation rates in the germ line and somatic tissues of the offspring of irradiated parents. The possible mechanisms of transgenerational instability are also discussed.

The Aorta-Gonad-Mesonephros Organ Culture Recapitulates 5hmC Reorganization and Replication-Dependent and Independent Loss of DNA Methylation in the Germline.

PubMed

Calvopina, Joseph Hargan; Cook, Helene; Vincent, John J; Nee, Kevin; Clark, Amander T

2015-07-01

Removal of cytosine methylation from the genome is critical for reprogramming and transdifferentiation and plays a central role in our understanding of the fundamental principles of embryo lineage development. One of the major models for studying cytosine demethylation is the mammalian germ line during the primordial germ cell (PGC) stage of embryo development. It is now understood that oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) is required to remove cytosine methylation in a locus-specific manner in PGCs; however, the mechanisms downstream of 5hmC are controversial and hypothesized to involve either active demethylation or replication-coupled loss. In the current study, we used the aorta-gonad-mesonephros (AGM) organ culture model to show that this model recapitulates germ line reprogramming, including 5hmC reorganization and loss of cytosine methylation from Snrpn and H19 imprinting control centers (ICCs). To directly address the hypothesis that cell proliferation is required for cytosine demethylation, we blocked PI3-kinase-dependent PGC proliferation and show that this leads to a G1 and G2/M cell cycle arrest in PGCs, together with retained levels of cytosine methylation at the Snrpn ICC, but not at the H19 ICC. Taken together, the AGM organ culture model is an important tool to evaluate mechanisms of locus-specific demethylation and the role of PI3-kinase-dependent PGC proliferation in the locus-specific removal of cytosine methylation from the genome.

Primordial Germ Cells in Mice

PubMed Central

Saitou, Mitinori; Yamaji, Masashi

2012-01-01

Germ cell development creates totipotency through genetic as well as epigenetic regulation of the genome function. Primordial germ cells (PGCs) are the first germ cell population established during development and are immediate precursors for both the oocytes and spermatogonia. We here summarize recent findings regarding the mechanism of PGC development in mice. We focus on the transcriptional and signaling mechanism for PGC specification, potential pluripotency, and epigenetic reprogramming in PGCs and strategies for the reconstitution of germ cell development using pluripotent stem cells in culture. Continued studies on germ cell development may lead to the generation of totipotency in vitro, which should have a profound influence on biological science as well as on medicine. PMID:23125014

nanos function is essential for development and regeneration of planarian germ cells.

PubMed

Wang, Yuying; Zayas, Ricardo M; Guo, Tingxia; Newmark, Phillip A

2007-04-03

Germ cells are required for the successful propagation of sexually reproducing species. Understanding the mechanisms by which these cells are specified and how their totipotency is established and maintained has important biomedical and evolutionary implications. Freshwater planarians serve as fascinating models for studying these questions. They can regenerate germ cells from fragments of adult tissues that lack reproductive structures, suggesting that inductive signaling is involved in planarian germ cell specification. To study the development and regeneration of planarian germ cells, we have functionally characterized an ortholog of nanos, a gene required for germ cell development in diverse organisms, from Schmidtea mediterranea. In the hermaphroditic strain of this species, Smed-nanos mRNA is detected in developing, regenerating, and mature ovaries and testes. However, it is not detected in the vast majority of newly hatched planarians or in small tissue fragments that will ultimately regenerate germ cells, consistent with an epigenetic origin of germ cells. We show that Smed-nanos RNA interference (RNAi) results in failure to develop, regenerate, or maintain gonads in sexual planarians. Unexpectedly, Smed-nanos mRNA is also detected in presumptive testes primordia of asexual individuals that reproduce strictly by fission. These presumptive germ cells are lost after Smed-nanos RNAi, suggesting that asexual planarians specify germ cells, but their differentiation is blocked downstream of Smed-nanos function. Our results reveal a conserved function of nanos in germ cell development in planarians and suggest that these animals will serve as useful models for dissecting the molecular basis of epigenetic germ cell specification.

Gtl2lacZ, an insertional mutation on mouse chromosome 12 with parental origin-dependent phenotype.

PubMed

Schuster-Gossler, K; Simon-Chazottes, D; Guenet, J L; Zachgo, J; Gossler, A

1996-01-01

We have produced a transgenic mouse line, Gtl2lacZ (Gene trap locus 2), that carries an insertional mutation with a dominant modified pattern of inheritance:heterozygous Gtl2lacZ mice that inherited the transgene from the father show a proportionate dwarfism phenotype, whereas the penetrance and expressivity of the phenotype is strongly reduced in Gtl2lacZ mice that inherited the transgene from the mother. On a mixed genetic background this pattern of inheritance was reversible upon transmission of the transgene through the germ line of the opposite sex. On a predominantly 129/Sv genetic background, however, transgene passage through the female germ line modified the transgene effect, such that the penetrance of the mutation was drastically reduced and the phenotype was no longer obvious after subsequent male germ line transmission. Expression of the transgene, however, was neither affected by genetic background nor by parental legacy. Gtl2lacZ maps to mouse Chromosome 12 in a region that displays imprinting effects associated with maternal and paternal disomy. Our results suggest that the transgene insertion in Gtl2lacZ mice affects an endogenous gene(s) required for fetal and postnatal growth and that this gene(s) is predominantly paternally expressed.

A Novel Class of Somatic Small RNAs Similar to Germ Cell Pachytene PIWI-interacting Small RNAs*

PubMed Central

Ortogero, Nicole; Schuster, Andrew S.; Oliver, Daniel K.; Riordan, Connor R.; Hong, Annie S.; Hennig, Grant W.; Luong, Dickson; Bao, Jianqiang; Bhetwal, Bhupal P.; Ro, Seungil; McCarrey, John R.; Yan, Wei

2014-01-01

PIWI-interacting RNAs (piRNAs) are small noncoding RNAs that bind PIWI family proteins exclusively expressed in the germ cells of mammalian gonads. MIWI2-associated piRNAs are essential for silencing transposons during primordial germ cell development, and MIWI-bound piRNAs are required for normal spermatogenesis during adulthood in mice. Although piRNAs have long been regarded as germ cell-specific, increasing lines of evidence suggest that somatic cells also express piRNA-like RNAs (pilRNAs). Here, we report the detection of abundant pilRNAs in somatic cells, which are similar to MIWI-associated piRNAs mainly expressed in pachytene spermatocytes and round spermatids in the testis. Based on small RNA deep sequencing and quantitative PCR analyses, pilRNA expression is dynamic and displays tissue specificity. Although pilRNAs are similar to pachytene piRNAs in both size and genomic origins, they have a distinct ping-pong signature. Furthermore, pilRNA biogenesis appears to utilize a yet to be identified pathway, which is different from all currently known small RNA biogenetic pathways. In addition, pilRNAs appear to preferentially target the 3′-UTRs of mRNAs in a partially complementary manner. Our data suggest that pilRNAs, as an integral component of the small RNA transcriptome in somatic cell lineages, represent a distinct population of small RNAs that may have functions similar to germ cell piRNAs. PMID:25320077

Avian Biotechnology.

PubMed

Nakamura, Yoshiaki

2017-01-01

Primordial germ cells (PGCs) generate new individuals through differentiation, maturation and fertilization. This means that the manipulation of PGCs is directly linked to the manipulation of individuals, making PGCs attractive target cells in the animal biotechnology field. A unique biological property of avian PGCs is that they circulate temporarily in the vasculature during early development, and this allows us to access and manipulate avian germ lines. Following the development of a technique for transplantation, PGCs have become central to avian biotechnology, in contrast to the use of embryo manipulation and subsequent transfer to foster mothers, as in mammalian biotechnology. Today, avian PGC transplantation combined with recent advanced manipulation techniques, including cell purification, cryopreservation, depletion, and long-term culture in vitro, have enabled the establishment of genetically modified poultry lines and ex-situ conservation of poultry genetic resources. This chapter introduces the principles, history, and procedures of producing avian germline chimeras by transplantation of PGCs, and the current status of avian germline modification as well as germplasm cryopreservation. Other fundamental avian reproductive technologies are described, including artificial insemination and embryo culture, and perspectives of industrial applications in agriculture and pharmacy are considered, including poultry productivity improvement, egg modification, disease resistance impairment and poultry gene "pharming" as well as gene banking.

Cryopreservation of putative pre-pubertal bovine spermatogonial stem cells by slow freezing.

PubMed

Kim, Ki-Jung; Lee, Yong-An; Kim, Bang-Jin; Kim, Yong-Hee; Kim, Byung-Gak; Kang, Hyun-Gu; Jung, Sang-Eun; Choi, Sun-Ho; Schmidt, Jonathan A; Ryu, Buom-Yong

2015-04-01

Development of techniques for the preservation of mammalian spermatogonial stem cells (SSCs) is a critical step in commercial application of SSC based technologies, including species preservation, amplification of agriculturally valuable germ lines, and human fertility preservations. The objective of this study was to develop an efficient cryopreservation protocol for preservation of bovine SSCs using a slow freezing technique. To maximize the efficiency of SSC cryopreservation, the effects of various methods (tissue vs. cell freezing) and cryoprotective agents (trehalose, sucrose, and polyethylene glycol [PEG]) were tested. Following thawing, cells were enriched for undifferentiated spermatogonia by differential plating and evaluated for recovery rate, proliferation capacity, and apoptosis. Additionally, putative stem cell activity was assessed using SSC xenotransplantation. The recovery rate, and proliferation capacity of undifferentiated spermatogonia were significantly greater for germ cells frozen using tissue freezing methods compared to cell freezing methods. Cryopreservation in the presence of 200 mM trehalose resulted in significantly greater recovery rate, proliferation capacity, and apoptosis of germ cells compared to control. Furthermore, cryopreservation using the tissue freezing method in the presence of 200 mM trehalose resulted in the production of colonies of donor-derived germ cells after xenotransplantation into recipient mouse testes, indicating putative stem cell function. Collectively, these data indicate that cryopreservation using tissue freezing methods in the presence of 200 mM trehalose is an efficient cryopreservation protocol for bovine SSCs. Copyright © 2015 Elsevier Inc. All rights reserved.

Insights into female germ cell biology: from in vivo development to in vitro derivations.

PubMed

Jung, Dajung; Kee, Kehkooi

2015-01-01

Understanding the mechanisms of human germ cell biology is important for developing infertility treatments. However, little is known about the mechanisms that regulate human gametogenesis due to the difficulties in collecting samples, especially germ cells during fetal development. In contrast to the mitotic arrest of spermatogonia stem cells in the fetal testis, female germ cells proceed into meiosis and began folliculogenesis in fetal ovaries. Regulations of these developmental events, including the initiation of meiosis and the endowment of primordial follicles, remain an enigma. Studying the molecular mechanisms of female germ cell biology in the human ovary has been mostly limited to spatiotemporal characterizations of genes or proteins. Recent efforts in utilizing in vitro differentiation system of stem cells to derive germ cells have allowed researchers to begin studying molecular mechanisms during human germ cell development. Meanwhile, the possibility of isolating female germline stem cells in adult ovaries also excites researchers and generates many debates. This review will mainly focus on presenting and discussing recent in vivo and in vitro studies on female germ cell biology in human. The topics will highlight the progress made in understanding the three main stages of germ cell developments: namely, primordial germ cell formation, meiotic initiation, and folliculogenesis.

The self-nonself discrimination and the nature and acquisition of the antibody repertoire.

PubMed

Coutinho, A

1980-01-01

Network ideas are confronted with current hypotheses for the origin of antibody diversity and self-nonself discrimination. The difficulties of reconciling the promethean evolution of the antibody system with "germ line" theories are discussed, as well as the problems of "somatic" hypotheses to explain the completeness of the antibody repertoire. The formal incompatibility of the network theory with ideas basing self-nonself discrimination on the elimination of self-reactive cells is demonstrated, as well as the difficulties of these and other environment-dependent hypotheses for lymphocyte activation, to encompass the internal activity in the immune system. It is argued, on the other hand, that the limitations of the network theory in providing a functional basis for the idiotypic network and in accounting for self-nonself discrimination, can be solved by finding in a complete repertoire of antibody-combining sites the complementary structures to growth receptors on B lymphocytes, and by using these as internal mitogens in the expansion of the precursor cell pools and in the maintenance of the mature steady states. Letting self-nonself discrimination be accounted for by such growth receptors, both the integrity of the antibody repertoire and the internal activity in the system can also be ensured. Moreover, by postulating a germ line origin for the antireceptor antibodies and by accepting idiotypic cross-reactivity between growth receptors and other germ line antibodies, the possibilities are set for a phylogenetically and ontogenically autonomous immune system embodied with the capabilities for self-expansion, diversification and selection of available repertoires. Its promethean characteristics are explained by its completeness, and this is achieved by idiotypic interactions between growth receptors and a limited number of complementary or cross-reactive germ line antibodies, naturally selected on the basis of their structural relationships with growth receptors.

S6K links cell fate, cell cycle and nutrient response in C. elegans germline stem/progenitor cells

PubMed Central

Korta, Dorota Z.; Tuck, Simon; Hubbard, E. Jane Albert

2012-01-01

Coupling of stem/progenitor cell proliferation and differentiation to organismal physiological demands ensures the proper growth and homeostasis of tissues. However, in vivo mechanisms underlying this control are poorly characterized. We investigated the role of ribosomal protein S6 kinase (S6K) at the intersection of nutrition and the establishment of a stem/progenitor cell population using the C. elegans germ line as a model. We find that rsks-1 (which encodes the worm homolog of mammalian p70S6K) is required germline-autonomously for proper establishment of the germline progenitor pool. In the germ line, rsks-1 promotes cell cycle progression and inhibits larval progenitor differentiation, promotes growth of adult tumors and requires a conserved TOR phosphorylation site. Loss of rsks-1 and ife-1 (eIF4E) together reduces the germline progenitor pool more severely than either single mutant and similarly to reducing the activity of let-363 (TOR) or daf-15 (RAPTOR). Moreover, rsks-1 acts in parallel with the glp-1 (Notch) and daf-2 (insulin-IGF receptor) pathways, and does not share the same genetic dependencies with its role in lifespan control. We show that overall dietary restriction and amino acid deprivation cause germline defects similar to a subset of rsks-1 mutant phenotypes. Consistent with a link between diet and germline proliferation via rsks-1, loss of rsks-1 renders the germ line largely insensitive to the effects of dietary restriction. Our studies establish the C. elegans germ line as an in vivo model to understand TOR-S6K signaling in proliferation and differentiation and suggest that this pathway is a key nutrient-responsive regulator of germline progenitors. PMID:22278922

Development of germ-line-specific CRISPR-Cas9 systems to improve the production of heritable gene modifications in Arabidopsis.

PubMed

Mao, Yanfei; Zhang, Zhengjing; Feng, Zhengyan; Wei, Pengliang; Zhang, Hui; Botella, José Ramón; Zhu, Jian-Kang

2016-02-01

The Streptococcus-derived CRISPR/Cas9 system is being widely used to perform targeted gene modifications in plants. This customized endonuclease system has two components, the single-guide RNA (sgRNA) for target DNA recognition and the CRISPR-associated protein 9 (Cas9) for DNA cleavage. Ubiquitously expressed CRISPR/Cas9 systems (UC) generate targeted gene modifications with high efficiency but only those produced in reproductive cells are transmitted to the next generation. We report the design and characterization of a germ-line-specific Cas9 system (GSC) for Arabidopsis gene modification in male gametocytes, constructed using a SPOROCYTELESS (SPL) genomic expression cassette. Four loci in two endogenous genes were targeted by both systems for comparative analysis. Mutations generated by the GSC system were rare in T1 plants but were abundant (30%) in the T2 generation. The vast majority (70%) of the T2 mutant population generated using the UC system were chimeras while the newly developed GSC system produced only 29% chimeras, with 70% of the T2 mutants being heterozygous. Analysis of two loci in the T2 population showed that the abundance of heritable gene mutations was 37% higher in the GSC system compared to the UC system and the level of polymorphism of the mutations was also dramatically increased with the GSC system. Two additional systems based on germ-line-specific promoters (pDD45-GT and pLAT52-GT) were also tested, and one of them was capable of generating heritable homozygous T1 mutant plants. Our results suggest that future application of the described GSC system will facilitate the screening for targeted gene modifications, especially lethal mutations in the T2 population. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Germ-line PHD1 and PHD2 mutations detected in patients with pheochromocytoma/paraganglioma-polycythemia.

PubMed

Yang, Chunzhang; Zhuang, Zhengping; Fliedner, Stephanie M J; Shankavaram, Uma; Sun, Michael G; Bullova, Petra; Zhu, Roland; Elkahloun, Abdel G; Kourlas, Peter J; Merino, Maria; Kebebew, Electron; Pacak, Karel

2015-01-01

We have investigated genetic/pathogenetic factors associated with a new clinical entity in patients presenting with pheochromocytoma/paraganglioma (PHEO/PGL) and polycythemia. Two patients without hypoxia-inducible factor 2α (HIF2A) mutations, who presented with similar clinical manifestations, were analyzed for other gene mutations, including prolyl hydroxylase (PHD) mutations. We have found for the first time a germ-line mutation in PHD1 in one patient and a novel germ-line PHD2 mutation in a second patient. Both mutants exhibited reduced protein stability with substantial quantitative protein loss and thus compromised catalytic activities. Due to the unique association of patients' polycythemia with borderline or mildly elevated erythropoietin (EPO) levels, we also performed an in vitro sensitivity assay of erythroid progenitors to EPO and for EPO receptor (EPOR) expression. The results show inappropriate hypersensitivity of erythroid progenitors to EPO in these patients, indicating increased EPOR expression/activity. In addition, the present study indicates that HIF dysregulation due to PHD mutations plays an important role in the pathogenesis of these tumors and associated polycythemia. The PHD1 mutation appears to be a new member contributing to the genetic landscape of this novel clinical entity. Our results support the existence of a specific PHD1- and PHD2-associated PHEO/PGL-polycythemia disorder. • A novel germ-l i n e PHD1 mutation causing heochromocytoma/paraganglioma and polycythemia. • Increased EPOR activity and inappropriate hypersensitivity of erythroid progenitors to EPO.

Analyzing Maize Anther Development Using Transposons

NASA Astrophysics Data System (ADS)

Han, S.

2011-12-01

Over the summer, we tackled two projects in studying more about transposons (moving/jumping genes) such as Mutator genes in corn for this project, and how the plants switch from the stages of mitosis to meiosis without a germ line. We use a transgenic corn line containing RescueMu (an artificial Mutator containing a plasmid in it), so we can keep track of the insertion events. This is a long term project so we haven't come to any final conclusions or results with tracking what happens in Mutator transposition during different stages of corn development but our process shows to work so we continue with what we've been doing.

Methylenetetrahydrofolate reductase gene polymorphisms and the risk of colorectal carcinoma in a sample of Egyptian individuals.

PubMed

El Awady, Mostafa K; Karim, Amr M; Hanna, Laila S; El Husseiny, Lamia A; El Sahar, Medhat; Menem, Hanan A Abdel; Meguid, Nagwa A

2009-01-01

The study was planned as a pilot study to investigate two common polymorphisms in the MTHFR gene c.677C > T and c.1298A > C and their association with enhanced risk of colorectal cancer (CRC) in a sample of Egyptian individuals. Venous blood samples were withdrawn from 35 cases of CRC and 68 healthy controls. Specimens from colonic and rectal carcinoma tissues in addition to cancer free tissues were obtained from all cases. Frequencies of MTHFR677T and 1298C alleles were significantly higher among cases of CRC tumor tissues (50% and 56%, respectively) than germ line alleles in CRC patients (33% and 41%, respectively) and healthy controls (21% and 35%, respectively). Frequencies of heterozygous and homoyzgous polymorphisms of MTHFR at positions 677 and 1298 in carcinoma tissues were always the highest. At position 677, TT and CT genotype frequencies were 17% and 66% with an odds ratio {OR} of 11 [95% confidence interval {CI} 2.39-50.59] and OR 8.34 [95%CI 2.97-23.92], respectively, in carcinoma tissues. While in the germ line of patients the genotype frequencies of 677TT and CT were 6% and 54% with OR 1.57 [95%CI 0.26-9.51] and 2.99 [95%CI 1.25-7.12], respectively, compared to controls (6% and 29%, respectively). The combined genotype MTHFR 1298CC + AC frequencies were 86% with OR 3.71 [95%CI 1.28-10.78] in carcinoma tissues, 69% with OR 1.35 [95%CI 0.57-3.21] in germ line of patients and 62% in controls. The combined genotype 677CT plus any of the following genotypes 1298AA, AC or CC enhanced risk of CRC, when comparing germ line DNA polymorphism of patients versus peripheral blood DNA of control subjects with OR 4.5 [95%CI 0.94-21.56], OR 3.12 [95%CI 0.79-12.36] and OR 18 [95%CI 1.56-207.5], respectively, suggesting strong genetic predisposition of certain Egyptian population to CRC. These results suggested that at least one C to T polymorphism at 677MTHFR gene is required to significantly increase the risk for CRC development. Further large scale studies are required to confirm the present findings.

Germ-line transmission of lentiviral PGK-EGFP integrants in transgenic cattle: new perspectives for experimental embryology.

PubMed

Reichenbach, Myriam; Lim, Tiongti; Reichenbach, Horst-Dieter; Guengoer, Tuna; Habermann, Felix A; Matthiesen, Marieke; Hofmann, Andreas; Weber, Frank; Zerbe, Holm; Grupp, Thomas; Sinowatz, Fred; Pfeifer, Alexander; Wolf, Eckhard

2010-08-01

Lentiviral vectors are a powerful tool for the genetic modification of livestock species. We previously generated transgenic founder cattle with lentiviral integrants carrying enhanced green fluorescent protein (EGFP) under the control of the phosphoglycerate kinase (PGK) promoter. In this study, we investigated the transmission of LV-PGK-EGFP integrants through the female and male germ line in cattle. A transgenic founder heifer (#562, Kiki) was subjected to superovulation treatment and inseminated with semen from a non-transgenic bull. Embryos were recovered and transferred to synchronized recipient heifers, resulting in the birth of a healthy male transgenic calf expressing EGFP as detected by in vivo imaging. Semen from a transgenic founder bull (#561, Jojo) was used for in vitro fertilization (IVF) of in vitro matured (IVM) oocytes from non-transgenic cows. The rates of cleavage and development to blastocyst in vitro corresponded to 52.0 +/- 4.1 and 24.5 +/- 4.4%, respectively. Expression of EGFP was observed at blastocyst stage (day 7 after IVF) and was seen in 93.0% (281/302) of the embryos. 24 EGFP-expressing embryos were transferred to 9 synchronized recipients. Analysis of 2 embryos, flushed from the uterus on day 15, two fetuses recovered on day 45, and a healthy male transgenic calf revealed consistent high-level expression of EGFP in all tissues investigated. Our study shows for the first time transmission of lentiviral integrants through the germ line of female and male transgenic founder cattle. The pattern of inheritance was consistent with Mendelian rules. Importantly, high fidelity expression of EGFP in embryos, fetuses, and offspring of founder #561 provides interesting tools for developmental studies in cattle, including interactions of gametes, embryos and fetuses with their maternal environment.

Insulated piggyBac vectors for insect transgenesis

PubMed Central

Sarkar, Abhimanyu; Atapattu, Asela; Belikoff, Esther J; Heinrich, Jörg C; Li, Xuelei; Horn, Carsten; Wimmer, Ernst A; Scott, Maxwell J

2006-01-01

Background Germ-line transformation of insects is now a widely used method for analyzing gene function and for the development of genetically modified strains suitable for pest control programs. The most widely used transposable element for the germ-line transformation of insects is piggyBac. The site of integration of the transgene can influence gene expression due to the effects of nearby transcription enhancers or silent heterochromatic regions. Position effects can be minimized by flanking a transgene with insulator elements. The scs/scs' and gypsy insulators from Drosophila melanogaster as well as the chicken β-globin HS4 insulator function in both Drosophila and mammalian cells. Results To minimize position effects we have created a set of piggyBac transformation vectors that contain either the scs/scs', gypsy or chicken β-globin HS4 insulators. The vectors contain either fluorescent protein or eye color marker genes and have been successfully used for germ-line transformation of Drosophila melanogaster. A set of the scs/scs' vectors contains the coral reef fluorescent protein marker genes AmCyan, ZsGreen and DsRed that have not been optimized for translation in human cells. These marker genes are controlled by a combined GMR-3xP3 enhancer/promoter that gives particularly strong expression in the eyes. This is also the first report of the use of the ZsGreen and AmCyan reef fluorescent proteins as transformation markers in insects. Conclusion The insulated piggyBac vectors should protect transgenes against position effects and thus facilitate fine control of gene expression in a wide spectrum of insect species. These vectors may also be used for transgenesis in other invertebrate species. PMID:16776846

Towards gene banking amphibian maternal germ lines: short-term incubation, cryoprotectant tolerance and cryopreservation of embryonic cells of the frog, Limnodynastes peronii.

PubMed

Lawson, Bianca; Clulow, Simon; Mahony, Michael J; Clulow, John

2013-01-01

Gene banking is arguably the best method available to prevent the loss of genetic diversity caused by declines in wild populations, when the causes of decline cannot be halted or reversed. For one of the most impacted vertebrate groups, the amphibians, gene banking technologies have advanced considerably, and gametes from the male line can be banked successfully for many species. However, cryopreserving the female germ line remains challenging, with attempts at cryopreserving oocytes unsuccessful due to their large size and yolk content. One possible solution is to target cryopreservation of early embryos that contain the maternal germ line, but consist of smaller cells. Here, we investigate the short term incubation, cryoprotectant tolerance, and cryopreservation of dissociated early embryonic cells from gastrulae and neurulae of the Striped Marsh Frog, Limnodynastes peronii. Embryos were dissociated and cells were incubated for up to 24 hours in various media. Viability of both gastrula and neurula cells remained high (means up to 40-60%) over 24 hours of incubation in all media, although viability was maintained at a higher level in Ca(2+)-free Simplified Amphibian Ringer; low speed centrifugation did not reduce cell viability. Tolerance of dissociated embryonic cells was tested for two cryoprotectants, glycerol and dimethyl sulphoxide; dissociated cells of both gastrulae and neurulae were highly tolerant to both-indeed, cell viability over 24 hours was higher in media containing low-to-medium concentrations than in equivalent cryoprotectant-free media. Viability over 24 hours was lower in concentrations of cryoprotectant higher than 10%. Live cells were recovered following cryopreservation of both gastrula and neurula cells, but only at low rates. Optimal cryodiluents were identified for gastrula and neurula cells. This is the first report of a slow cooling protocol for cryopreservation of amphibian embryonic cells, and sets future research directions for cryopreserving amphibian maternal germ lines.

Developmentally regulated expression of APG-1, a member of heat shock protein 110 family in murine male germ cells.

PubMed

Kaneko, Y; Kimura, T; Nishiyama, H; Noda, Y; Fujita, J

1997-04-07

Apg-1 encodes a heat shock protein belonging to the heat shock protein 110 family, and is inducible by a 32 degrees C to 39 degrees C heat shock. Northern blot analysis of the testis from immature and adult mice, and of the purified germ cells revealed the quantitative change of the apg-1 transcripts during germ cell development. By in situ hybridization histochemistry the expressions of the apg-1 transcripts were detected in germ cells at specific stages of development including spermatocytes and spermatids. Although heat-induction of the apg-1 transcripts was observed in W/Wv mutant testis lacking germ cells, it was not detected in wild-type testis nor in the purified germ cells. Thus, the apg-1 expression is not heat-regulated but developmentally regulated in germ cells, suggesting that APG-1 plays a role in normal development of germ cells.

Germ cells in the teleost fish medaka have an inherent feminizing effect

PubMed Central

Nishimura, Toshiya; Yamada, Kazuki; Fujimori, Chika; Kikuchi, Mariko; Kawasaki, Toshihiro; Siegfried, Kellee R.; Sakai, Noriyoshi

2018-01-01

Germ cells give rise to eggs or sperm. However, recent analyses in medaka (Oryzias latipes) showed that germ cells are also important for feminization of gonads, although this novel role of germ cells has not been characterized in detail. Here, we show that the feminizing effect is inherent to germ cells and is not affected by gametogenic stages or the sexual fate of germ cells. Three medaka mutants were generated to demonstrate this effect: figlα mutants, in which follicle formation is disrupted; meioC mutants, in which germ cells are unable to commit to gametogenesis and meiosis; and dazl mutants, in which germ cells do not develop into gonocytes. All these different stages of germ cells in XX mutants have an ability to feminize the gonads, resulting in the formation of gonads with ovarian structures. In addition to normal ovarian development, we also suggest that the increased number of gonocytes is sufficient for male to female sex reversal in XY medaka. These results may genetically demonstrate that the mechanism underlying the feminizing effect of germ cells is activated before the sexual fate decision of germ cells and meiosis, probably by the time of gonocyte formation in medaka. Author summary Germ cells are the only cells that can transfer genetic materials to the next generation via the sperm or egg. However, recent analyses in teleosts revealed another essential role of germ cells: feminizing the gonads. In our study, medaka mutants in which gametogenesis was blocked at specific stages provides the novel view that the feminizing effect of germ cells occurs in parallel with other reproductive elements, such as meiosis, the sexual fate decision of germ cells, and gametogenesis. Germ cells in medaka may have a potential to feminize gonads at the moment they have developed. PMID:29596424

The relationship between sperm function and diet: toms are what they eat

USDA-ARS?s Scientific Manuscript database

It is well known that cryopreserved semen could be used to regenerate commercial or research poultry lines; however, fertility rates from poultry semen frozen with current methods are not reliable enough for germ-line retrieval, especially from lines with low reproductive efficiency. As part of a l...

[Treatment of testicular cancer].

PubMed

Droz, Jean-Pierre; Boyle, Helen; Culine, Stéphane; Fizazi, Karim; Fléchon, Aude; Massard, Christophe

2013-12-01

Germ-cell tumours (GCTs) are the most common type of cancer in young men. Since the late 1970s, disseminated GCT have been a paradigm for curable metastatic cancer and metastatic GCTs are highly curable with cisplatin-based chemotherapy followed by surgical resection of residual masses. Patients' prognosis is currently assessed using the International Germ-Cell Consensus Classification (IGCCC) and used to adapt the burden of chemotherapy. Approximately 20% of patients still do not achieve cure after first-line cisplatin-based chemotherapy, and need salvage chemotherapy (high dose or standard dose chemotherapy). Clinical stage I testicular cancer is the most common presentation and different strategies are proposed: adjuvant therapies, surgery or surveillance. During the last three decades, clinical trials and strong international collaborations lead to the development of a consensus in the management of GCTs.

Cox-1 Suppression and Follicle Depletion in the Etiology of Menopause- Associated Ovarian Cancer

DTIC Science & Technology

2008-04-01

follicular function (2). Most oocytes are progressively lost by atresia, or apoptosis (3), and the ovary may develop a number of atrophic features...the risk of ovarian epithelial cancers, by far the most predominant form (14), and cause growth inhibition and apoptosis in ovarian cancer cell lines...1990;4:390-400. 8. Mintz B. Embryological development of primordial germ-cells in the mouse: influence of a new mutation, Wj. J Embryol Exp

A Case of Mixed Germ Cell Tumor in the Intramedullary Spinal-cord.

PubMed

Nitta, Masahiro; Hoshi, Akio; Higure, Taro; Shimizu, Yuki; Nakajima, Nobuyuki; Hanai, Kazuya; Kawamura, Yoshiaki; Terachi, Toshiro

2016-09-20

A 28-year-old man was hospitalized with advancing paraplegia. Under the diagnosis of Guillain-Barre syndrome, steroid pulse therapy was administered and plasmapheresis was performed. However, the paraplegia gradually progressed. Subsequently, a spinal cord tumor was revealed by magnetic resonance imaging (MRI). The pathological diagnosis, obtained by open biopsy, confirmed a mixed germ cell tumor in the spinal cord. Multiple lung and lymph nodes metastases were also detected upon computed tomography, along with increased serum alpha-fetoprotein (33.9 ng/mL) and human chorionic gonadotropin (182.5 mIU/mL) levels. Consequently, he received chemotherapy comprising three courses of BEP (bleomycin, etoposide, and cisplatin) as first-line therapy, followed by four courses of TGN (paclitaxel, gemcitabine, and nedaplatin) as second-line treatment. As a result, the spinal cord lesion area was significantly decreased and the alpha-fetoprotein and human chorionic gonadotropin levels were normalized. Four years after chemotherapy, MRI revealed pituitary gland and pineal organ recurrence of the germ cell tumor and additional TGN chemotherapy was performed.

Germ line genome editing in clinics: the approaches, objectives and global society.

PubMed

Ishii, Tetsuya

2017-01-01

Genome editing allows for the versatile genetic modification of somatic cells, germ cells and embryos. In particular, CRISPR/Cas9 is worldwide used in biomedical research. Although the first report on Cas9-mediated gene modification in human embryos focused on the prevention of a genetic disease in offspring, it raised profound ethical and social concerns over the safety of subsequent generations and the potential misuse of genome editing for human enhancement. The present article considers germ line genome editing approaches from various clinical and ethical viewpoints and explores its objectives. The risks and benefits of the following three likely objectives are assessed: the prevention of monogenic diseases, personalized assisted reproductive technology (ART) and genetic enhancement. Although genetic enhancement should be avoided, the international regulatory landscape suggests the inevitability of this misuse at ART centers. Under these circumstances, possible regulatory responses and the potential roles of public dialogue are discussed. © The Author 2015. Published by Oxford University Press.

Models of germ cell development and their application for toxicity studies

PubMed Central

Ferreira, Daniel W.; Allard, Patrick

2015-01-01

Germ cells are unique in their ability to transfer genetic information and traits from generation to generation. As such, the proper development of germ cells and the integrity of their genome are paramount to the health of organisms and the survival of species. Germ cells are also exquisitely sensitive to environmental influences although the testing of germ cell toxicity, especially in females, has proven particularly challenging. In this review, we first describe the remarkable odyssey of germ cells in mammals, with an emphasis on the female germline, from their initial specification during embryogenesis to the generation of mature gametes in adults. We also describe the current methods used in germ cell toxicity testing and their limitations in examining the complex features of mammalian germ cell development. To bypass these challenges, we propose the use of alternative model systems such as Saccharomyces cerevisiae, Drosophila melanogaster, Caenorhabditis elegans and in vitro germ cell methods that have distinct advantages over traditional toxicity models. We discuss the benefits and limitations of each approach, their application to germ cell toxicity studies, and the need for computational approaches to maximize the usefulness of these models. Together, the inclusion of these alternative germ cell toxicity models will be invaluable for the examination of stages not easily accessible in mammals as well as the large scale, high-throughput investigation of germ cell toxicity. PMID:25821157

A Human Anti-Insulin IgG Autoantibody Apparently Arises Through Clonal Selection from an Insulin-Specific “Germ-Line” Natural Antibody Template

PubMed Central

Ichiyoshi, Yuji; Zhou, Min; Casali, Paolo

2015-01-01

We analyzed the structural correlates underlying the insulin-dependent selection of the specific anti-insulin IgG1 κ mAb13-producing cell clone, derived from a patient with insulin-dependent diabetes mellitus treated with recombinant human insulin. First, we cloned the germ-line genes that putatively gave rise to the expressed VH and Vκ segments and used them to generate the full (unmutated) “germ-line revertant” of the “wild-type” (somatically mutated) mAb13, using recombinant PCR methods and an in vitro human Cγ1 and Cκ expression system. The full “germ-line revertant” bound insulin specifically and in a dose-saturable fashion, but with a relative avidity (Avrel) more than three-fold lower than that of its wild-type counterpart (Avrel, 1.69 × 10−8 vs 4.91 × 10−9 g/μl). Second, we established, by reassorting wild-type and germ-line revertant forms of the mAb13 VH and Vκ segments, that the increased Avrel for insulin of mAb13 when compared with its full “germ-line revertant” counterpart was entirely dependent on the mutations in the VH not those in the Vκ chain. Third, we determined, by site-directed mutagenesis experiments, that of the three mutations in the mAb13 VH segment (Ser→Gly, Ser→Thr, and Ser→Arg at positions 31, 56, and 58, respectively), only Arg58 was crucial in increasing the mAb13 Avrel (from 1.44 × 10−8 to 5.14 × 10−9 g/μl) and affinity (Kd, from 189 to 59 nM) for insulin. The affinity enhancement mediated by the VH segment Arg58 residue reflected about a threefold decrease in dissociation rate constant (Koff, from 4.92 × 10−3 to 1.54 × 10−3 s−1)but not an increase in association rate constant (Kon, from 2.60 × 104 to 2.61 × 104 M−1 s−1), and it contrasted with the complete loss of insulin binding resulting from the substitution of the VH segment Asn52 by Lys. The present findings suggest that human insulin, a self Ag, has the potential to recruit a natural autoantibody-producing cell precursor expressing a specific surface receptor for Ag in unmutated configuration, and drive it through affinity maturation. They also show that binding of insulin by such a receptor can be enhanced or completely abrogated by a single amino acid change. PMID:7995943

The evolution of ageing and longevity.

PubMed

Kirkwood, T B; Holliday, R

1979-09-21

Ageing is not adaptive since it reduces reproductive potential, and the argument that it evolved to provide offspring with living space is hard to sustain for most species. An alternative theory is based on the recognition that the force of natural selection declines with age, since in most environments individuals die from predation, disease or starvation. Ageing could therefore be the combined result of late-expressed deleterious genes which are beyond the reach of effective negative selection. However, this argument is circular, since the concept of 'late expression' itself implies the prior existence of adult age-related physiological processes. Organisms that do not age are essentially in a steady state in which chronologically young and old individuals are physiologically the same. In this situation the synthesis of macromolecules must be sufficiently accurate to prevent error feedback and the development of lethal 'error catastrophes'. This involves the expenditure of energy, which is required for both kinetic proof-reading and other accuracy promoting devices. It may be selectively advantageous for higher organisms to adopt an energy saving strategy of reduced accuracy in somatic cells to accelerate development and reproduction, but the consequence will be eventual deterioration and death. This 'disposable soma' theory of the evolution of ageing also proposes that a high level of accuracy is maintained in immortal germ line cells, or alternatively, that any defective germ cells are eliminated. The evolution of an increase in longevity in mammals may be due to a concomitant reduction in the rates of growth and reproduction and an increase in the accuracy of synthesis of macromolecules. The theory can be tested by measuring accuracy in germ line and somatic cells and also by comparing somatic cells from mammals with different longevities.

Testicular germ line cell identification, isolation, and transplantation in two North American catfish species.

PubMed

Shang, Mei; Su, Baofeng; Perera, Dayan A; Alsaqufi, Ahmed; Lipke, Elizabeth A; Cek, Sehriban; Dunn, David A; Qin, Zhenkui; Peatman, Eric; Dunham, Rex A

2018-04-01

Our aim was to transplant blue catfish germ line stem cells into blastulae of triploid channel catfish embryos to produce interspecific xenogenic catfish. The morphological structure of the gonads of blue catfish (Ictalurus furcatus) in ~ 90- to 100-day-old juveniles, two-year-old juveniles, and mature adults was studied histologically. Both oogonia (12-15 μm, diameter with distinct nucleus 7-8 μm diameter) and spermatogonia (12-15 μm, with distinct nucleus 6-7.5 μm diameter) were found in all ages of fish. The percentage of germ line stem cells was higher in younger blue catfish of both sexes. After the testicular tissue was trypsinized, a discontinuous density gradient centrifugation was performed using 70, 45, and 35% Percoll to enrich the percentage of spermatogonial stem cells (SSCs). Four distinct cell bands were generated after the centrifugation. It was estimated that 50% of the total cells in the top band were type A spermatogonia (diameter 12-15 μm) and type B spermatogonia (diameter 10-11 μm). Germ cells were confirmed with expression of vasa. Blastula-stage embryos of channel catfish (I. punctatus) were injected with freshly dissociated blue catfish testicular germ cells as donor cells for transplantation. Seventeen days after the transplantation, 33.3% of the triploid channel catfish fry were determined to be xenogenic catfish. This transplantation technique was efficient, and these xenogenic channel catfish need to be grown to maturity to verify their reproductive capacity and to verify that for the first time SSCs injected into blastulae were able to migrate to the genital ridge and colonize. These results open the possibility of artificially producing xenogenic channel catfish males that can produce blue catfish sperm and mate with normal channel catfish females naturally. The progeny would be all C × B hybrid catfish, and the efficiency of hybrid catfish production could be improved tremendously in the catfish industry.

Development, differentiation and manipulation of chicken germ cells.

PubMed

Nakamura, Yoshiaki; Kagami, Hiroshi; Tagami, Takahiro

2013-01-01

Germ cells are the only cell type capable of transmitting genetic information to the next generation. During development, they are set aside from all somatic cells of the embryo. In many species, germ cells form at the fringe of the embryo proper and then traverse through several developing somatic tissues on their migration to the emerging gonads. Primordial germ cells (PGCs) are the only cells in developing embryos with the potential to transmit genetic information to the next generation. Unlike other species, in avian embryos, PGCs use blood circulation for transport to the future gonadal region. This unique accessibility of avian PGCs during early development provides an opportunity to collect and transplant PGCs. The recent development of methods for production of germline chimeras by transfer of PGCs, and long-term cultivation methods of chicken PGCs without losing their germline transmission ability have provided important breakthroughs for the preservation of germplasm , for the production of transgenic birds and study the germ cell system. This review will describe the development, migration, differentiation and manipulation of germ cells, and discuss the prospects that germ cell technologies offer for agriculture, biotechnology and academic research. © 2013 The Authors Development, Growth & Differentiation © 2013 Japanese Society of Developmental Biologists.

Detection of insect damage in almonds

NASA Astrophysics Data System (ADS)

Kim, Soowon; Schatzki, Thomas F.

1999-01-01

Pinhole insect damage in natural almonds is very difficult to detect on-line. Further, evidence exists relating insect damage to aflatoxin contamination. Hence, for quality and health reasons, methods to detect and remove such damaged nuts are of great importance in this study, we explored the possibility of using x-ray imaging to detect pinhole damage in almonds by insects. X-ray film images of about 2000 almonds and x-ray linescan images of only 522 pinhole damaged almonds were obtained. The pinhole damaged region appeared slightly darker than non-damaged region in x-ray negative images. A machine recognition algorithm was developed to detect these darker regions. The algorithm used the first order and the second order information to identify the damaged region. To reduce the possibility of false positive results due to germ region in high resolution images, germ detection and removal routines were also included. With film images, the algorithm showed approximately an 81 percent correct recognition ratio with only 1 percent false positives whereas line scan images correctly recognized 65 percent of pinholes with about 9 percent false positives. The algorithms was very fast and efficient requiring only minimal computation time. If implemented on line, theoretical throughput of this recognition system would be 66 nuts/second.

Germ-line activation of the luteinizing hormone receptor directly drives spermiogenesis in a nonmammalian vertebrate

PubMed Central

Chauvigné, François; Zapater, Cinta; Gasol, Josep M.; Cerdà, Joan

2014-01-01

In both mammals and teleosts, the differentiation of postmeiotic spermatids to spermatozoa (spermiogenesis) is thought to be indirectly controlled by the luteinizing hormone (LH) acting through the LH/choriogonadotropin receptor (LHCGR) to stimulate androgen secretion in the interstitial Leydig cells. However, a more direct, nonsteroidal role of LH mediating the spermiogenic pathway remains unclear. Using a flatfish with semicystic spermatogenesis, in which spermatids are released into the seminiferous lobule lumen (SLL), where they develop into spermatozoa without direct contact with the supporting Sertoli cells, we show that haploid spermatids express the homolog of the tetrapod LHCGR (Lhcgrba). Both native Lh and intramuscularly injected His-tagged recombinant Lh (rLh) are immunodetected bound to the Lhcgrba of free spermatids in the SLL, showing that circulating gonadotropin can reach the intratubular compartment. In vitro incubation of flatfish spermatids isolated from the SLL with rLh specifically promotes their differentiation into spermatozoa, whereas recombinant follicle-stimulating hormone and steroid hormones are ineffective. Using a repertoire of molecular markers and inhibitors, we find that the Lh-Lhcgrba induction of spermiogenesis is mediated through a cAMP/PKA signaling pathway that initiates the transcription of genes potentially involved in the function of spermatozoa. We further show that Lhcgrba expression in germ cells also occurs in distantly related fishes, suggesting this feature is likely conserved in teleosts regardless of the type of germ cell development. These data reveal a role of LH in vertebrate germ cells, whereby a Lhcgrba-activated signaling cascade in haploid spermatids directs gene expression and the progression of spermiogenesis. PMID:24474769

Novel functions for the RNA-binding protein ETR-1 in Caenorhabditis elegans reproduction and engulfment of germline apoptotic cell corpses

PubMed Central

Boateng, Ruby; Nguyen, Ken C.Q.; Hall, David H.; Golden, Andy; Allen, Anna K.

2017-01-01

RNA-binding proteins (RBPs) are essential regulators of gene expression that act through a variety of mechanisms to ensure the proper post-transcriptional regulation of their target RNAs. RBPs in multiple species have been identified as playing crucial roles during development and as having important functions in various adult organ systems, including the heart, nervous, muscle, and reproductive systems. ETR-1, a highly conserved ELAV-Type RNA-binding protein belonging to the CELF/Bruno protein family, has been previously reported to be involved in C. elegans muscle development. Animals depleted of ETR-1 have been previously characterized as arresting at the two-fold stage of embryogenesis. In this study, we show that ETR-1 is expressed in the hermaphrodite somatic gonad and germ line, and that reduction of ETR-1 via RNA interference (RNAi) results in reduced hermaphrodite fecundity. Detailed characterization of this fertility defect indicates that ETR-1 is required in both the somatic tissue and the germ line to ensure wild-type reproductive levels. Additionally, the ability of ETR-1 depletion to suppress the published WEE-1.3-depletion infertility phenotype is dependent on ETR-1 being reduced in the soma. Within the germline of etr-1(RNAi) hermaphrodite animals, we observe a decrease in average oocyte size and an increase in the number of germline apoptotic cell corpses as evident by an increased number of CED-1::GFP and acridine orange positive apoptotic germ cells. Transmission Electron Microscopy (TEM) studies confirm the significant increase in apoptotic cells in ETR-1-depleted animals, and reveal a failure of the somatic gonadal sheath cells to properly engulf dying germ cells in etr-1(RNAi) animals. Through investigation of an established engulfment pathway in C. elegans, we demonstrate that co-depletion of CED-1 and ETR-1 suppresses both the reduced fecundity and the increase in the number of apoptotic cell corpses observed in etr-1(RNAi) animals. Combined, this data identifies a novel role for ETR-1 in hermaphrodite gametogenesis and in the process of engulfment of germline apoptotic cell corpses. PMID:28648844

The planarian nanos-like gene Smednos is expressed in germline and eye precursor cells during development and regeneration.

PubMed

Handberg-Thorsager, Mette; Saló, Emili

2007-05-01

Planarians are highly regenerative organisms with the ability to remake all their cell types, including the germ cells. The germ cells have been suggested to arise from totipotent neoblasts through epigenetic mechanisms. Nanos is a zinc-finger protein with a widely conserved role in the maintenance of germ cell identity. In this work, we describe the expression of a planarian nanos-like gene Smednos in two kinds of precursor cells namely, primordial germ cells and eye precursor cells, during both development and regeneration of the planarian Schmidtea mediterranea. In sexual planarians, Smednos is expressed in presumptive male primordial germ cells of embryos from stage 8 of embryogenesis and throughout development of the male gonads and in the female primordial germ cells of the ovary. Thus, upon hatching, juvenile planarians do possess primordial germ cells. In the asexual strain, Smednos is expressed in presumptive male and female primordial germ cells. During regeneration, Smednos expression is maintained in the primordial germ cells, and new clusters of Smednos-positive cells appear in the regenerated tissue. Remarkably, during the final stages of development (stage 8 of embryogenesis) and during regeneration of the planarian eye, Smednos is expressed in cells surrounding the differentiating eye cells, possibly corresponding to eye precursor cells. Our results suggest that similar genetic mechanisms might be used to control the differentiation of precursor cells during development and regeneration in planarians.

Molecular cloning and functional analysis of ESGP, an embryonic stem cell and germ cell specific protein.

PubMed

Chen, Yan-Mei; Du, Zhong-Wei; Yao, Zhen

2005-12-01

Several putative Oct-4 downstream genes from mouse embryonic stem (ES) cells have been identified using the suppression-subtractive hybridization method. In this study, one of the novel genes encoding an ES cell and germ cell specific protein (ESGP) was cloned by rapid amplification of cDNA ends. ESGP contains 801 bp encoding an 84 amino acid small protein and has no significant homology to any known genes. There is a signal peptide at the N-terminal of ESGP protein as predicted by SeqWeb (GCG) (SeqWeb version 2.0.2, http://gcg.biosino.org:8080/). The result of immunofluorescence assay suggested that ESGP might encode a secretory protein. The expression pattern of ESGP is consistent with the expression of Oct-4 during embryonic development. ESGP protein was detected in fertilized oocyte, from 3.5 day postcoital (dpc) blastocyst to 17.5 dpc embryo, and was only detected in testis and ovary tissues in adult. In vitro, ESGP was only expressed in pluripotent cell lines, such as embryonic stem cells, embryonic caoma cells and embryonic germ cells, but not in their differentiated progenies. Despite its specific expression, forced expression of ESGP is not indispensable for the effect of Oct-4 on ES cell self-renewal, and does not affect the differentiation to three germ layers.

Quantification of vitamin E and gamma-oryzanol components in rice germ and bran.

PubMed

Yu, Shanggong; Nehus, Zachary T; Badger, Thomas M; Fang, Nianbai

2007-09-05

Rice bran is a rich natural source of vitamin E and gamma-oryzanol, which have been extensively studied and reported to possess important health-promoting properties. However, commercial rice bran is a mixture of rice bran and germ, and profiles of vitamin E and gamma-oryzanol components in these two different materials are less well-studied. In the current study, vitamin E and gamma-oryzanol components in rice bran and germ were analyzed by liquid chromatography/mass spectrometry/mass spectrometry. The components were identified by electrospray ionization mass spectrometry (ESI-MS) with both positive- and negative-ion modes. Both deprotonated molecular ion [M - H](-) and protonated molecular ion [M + H](+) found as the base peaks in spectra of vitamin E components made ESI-MS a valuable analytic method in detecting vitamin E compounds, especially when they were at very low levels in samples. Ultraviolet absorption was used for quantification of vitamin E and gamma-oryzanol components. While the level of vitamin E in rice germ was 5 times greater than in rice bran, the level of gamma-oryzanol in rice germ was 5 times lower than in rice bran. Also, the major vitamin E component was alpha-tocopherol in rice germ and gamma-tocotrienol in rice bran. These data suggest that rice bran and germ have significantly different profiles of vitamin E and gamma-oryzanol components. The method enables rapid and direct on-line identification and quantification of the vitamin E and gamma-oryzanol components in rice bran and germ.

Global DNA methylation in fetal human germ cells and germ cell tumours: association with differentiation and cisplatin resistance.

PubMed

Wermann, Hendrik; Stoop, Hans; Gillis, Ad J M; Honecker, Friedemann; van Gurp, Ruud J H L M; Ammerpohl, Ole; Richter, Julia; Oosterhuis, J Wolter; Bokemeyer, Carsten; Looijenga, Leendert H J

2010-08-01

Differences in the global methylation pattern, ie hyper- as well as hypo-methylation, are observed in cancers including germ cell tumours (GCTs). Related to their precursor cells, GCT methylation status differs according to histology. We investigated the methylation pattern of normal fetal, infantile, and adult germ cells (n = 103) and GCTs (n = 251) by immunohistochemical staining for 5-(m)cytidine. The global methylation pattern of male germ cells changes from hypomethylation to hypermethylation, whereas female germ cells remain unmethylated at all stages. Undifferentiated GCTs (seminomas, intratubular germ cell neoplasia unclassified, and gonadoblastomas) are hypomethylated, whereas more differentiated GCTs (teratomas, yolk sac tumours, and choriocarcinomas) show a higher degree of methylation. Embryonal carcinomas show an intermediate pattern. Resistance to cisplatin was assessed in the seminomatous cell line TCam-2 before and after demethylation using 5-azacytidine. Exposure to 5-azacytidine resulted in decreased resistance to cisplatin. Furthermore, after demethylation, the stem cell markers NANOG and POU5F1 (OCT3/4), as well as the germ cell-specific marker VASA, showed increased expression. Following treatment with 5-azacytidine, TCam-2 cells were analysed using a high-throughput methylation screen for changes in the methylation sites of 14,000 genes. Among the genes revealing changes, interesting targets were identified: ie demethylation of KLF11, a putative tumour suppressor gene, and hypermethylation of CFLAR, a gene previously described in treatment resistance in GCTs.

Role of maternal Xenopus syntabulin in germ plasm aggregation and primordial germ cell specification.

PubMed

Oh, Denise; Houston, Douglas W

2017-12-15

The localization and organization of mitochondria- and ribonucleoprotein granule-rich germ plasm is essential for many aspects of germ cell development. In Xenopus, germ plasm is maternally inherited and is required for the specification of primordial germ cells (PGCs). Germ plasm is aggregated into larger patches during egg activation and cleavage and is ultimately translocated perinuclearly during gastrulation. Although microtubule dynamics and a kinesin (Kif4a) have been implicated in Xenopus germ plasm localization, little is known about how germ plasm distribution is regulated. Here, we identify a role for maternal Xenopus Syntabulin in the aggregation of germ plasm following fertilization. We show that depletion of sybu mRNA using antisense oligonucleotides injected into oocytes results in defects in the aggregation and perinuclear transport of germ plasm and subsequently in reduced PGC numbers. Using live imaging analysis, we also characterize a novel role for Sybu in the collection of germ plasm in vegetal cleavage furrows by surface contraction waves. Additionally, we show that a localized kinesin-like protein, Kif3b, is also required for germ plasm aggregation and that Sybu functionally interacts with Kif3b and Kif4a in germ plasm aggregation. Overall, these data suggest multiple coordinate roles for kinesins and adaptor proteins in controlling the localization and distribution of a cytoplasmic determinant in early development. Copyright © 2017 Elsevier Inc. All rights reserved.

Musashi Protein-directed Translational Activation of Target mRNAs Is Mediated by the Poly(A) Polymerase, Germ Line Development Defective-2*

PubMed Central

Cragle, Chad; MacNicol, Angus M.

2014-01-01

The mRNA-binding protein, Musashi, has been shown to regulate translation of select mRNAs and to control cellular identity in both stem cells and cancer cells. Within the mammalian cells, Musashi has traditionally been characterized as a repressor of translation. However, we have demonstrated that Musashi is an activator of translation in progesterone-stimulated oocytes of the frog Xenopus laevis, and recent evidence has revealed Musashi's capability to function as an activator of translation in mammalian systems. The molecular mechanism by which Musashi directs activation of target mRNAs has not been elucidated. Here, we report a specific association of Musashi with the noncanonical poly(A) polymerase germ line development defective-2 (GLD2) and map the association domain to 31 amino acids within the C-terminal domain of Musashi. We show that loss of GLD2 interaction through deletion of the binding domain or treatment with antisense oligonucleotides compromises Musashi function. Additionally, we demonstrate that overexpression of both Musashi and GLD2 significantly enhances Musashi function. Finally, we report a similar co-association also occurs between murine Musashi and GLD2 orthologs, suggesting that coupling of Musashi to the polyadenylation apparatus is a conserved mechanism to promote target mRNA translation. PMID:24644291

ASXL1 and BIM germ line variants predict response and identify CML patients with the greatest risk of imatinib failure

PubMed Central

Marum, Justine E.; Yeung, David T.; Purins, Leanne; Reynolds, John; Parker, Wendy T.; Stangl, Doris; Wang, Paul P. S.; Price, David J.; Tuke, Jonathan; Schreiber, Andreas W.; Scott, Hamish S.; Hughes, Timothy P.

2017-01-01

Scoring systems used at diagnosis of chronic myeloid leukemia (CML), such as Sokal risk, provide important response prediction for patients treated with imatinib. However, the sensitivity and specificity of scoring systems could be enhanced for improved identification of patients with the highest risk. We aimed to identify genomic predictive biomarkers of imatinib response at diagnosis to aid selection of first-line therapy. Targeted amplicon sequencing was performed to determine the germ line variant profile in 517 and 79 patients treated with first-line imatinib and nilotinib, respectively. The Sokal score and ASXL1 rs4911231 and BIM rs686952 variants were independent predictors of early molecular response (MR), major MR, deep MRs (MR4 and MR4.5), and failure-free survival (FFS) with imatinib treatment. In contrast, the ASXL1 and BIM variants did not consistently predict MR or FFS with nilotinib treatment. In the imatinib-treated cohort, neither Sokal or the ASXL1 and BIM variants predicted overall survival (OS) or progression to accelerated phase or blast crisis (AP/BC). The Sokal risk score was combined with the ASXL1 and BIM variants in a classification tree model to predict imatinib response. The model distinguished an ultra-high-risk group, representing 10% of patients, that predicted inferior OS (88% vs 97%; P = .041), progression to AP/BC (12% vs 1%; P = .034), FFS (P < .001), and MRs (P < .001). The ultra-high-risk patients may be candidates for more potent or combination first-line therapy. These data suggest that germ line genetic variation contributes to the heterogeneity of response to imatinib and may contribute to a prognostic risk score that allows early optimization of therapy. PMID:29296778

Co-chaperone Hsp70/Hsp90-organizing protein (Hop) is required for transposon silencing and Piwi-interacting RNA (piRNA) biogenesis.

PubMed

Karam, Joseph A; Parikh, Rasesh Y; Nayak, Dhananjaya; Rosenkranz, David; Gangaraju, Vamsi K

2017-04-14

Piwi-interacting RNAs (piRNAs) are 26-30-nucleotide germ line-specific small non-coding RNAs that have evolutionarily conserved function in mobile genetic element (transposons) silencing and maintenance of genome integrity. Drosophila Hsp70/90-organizing protein homolog (Hop), a co-chaperone, interacts with piRNA-binding protein Piwi and mediates silencing of phenotypic variations. However, it is not known whether Hop has a direct role in piRNA biogenesis and transposon silencing. Here, we show that knockdown of Hop in the germ line nurse cells (GLKD) of Drosophila ovaries leads to activation of transposons. Hop GLKD females can lay eggs at the same rate as wild-type counterparts, but the eggs do not hatch into larvae. Hop GLKD leads to the accumulation of γ-H2Av foci in the germ line, indicating increased DNA damage in the ovary. We also show that Hop GLKD-induced transposon up-regulation is due to inefficient piRNA biogenesis. Based on these results, we conclude that Hop is a critical component of the piRNA pathway and that it maintains genome integrity by silencing transposons. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Mismatch repair deficiency does not enhance ENU mutagenesis in the zebrafish germ line.

PubMed

Feitsma, Harma; de Bruijn, Ewart; van de Belt, Jose; Nijman, Isaac J; Cuppen, Edwin

2008-07-01

S(N)1-type alkylating agents such as N-ethyl-N-nitrosourea (ENU) are very potent mutagens. They act by transferring their alkyl group to DNA bases, which, upon mispairing during replication, can cause single base pair mutations in the next replication cycle. As DNA mismatch repair (MMR) proteins are involved in the recognition of alkylation damage, we hypothesized that ENU-induced mutation rates could be increased in a MMR-deficient background, which would be beneficial for mutagenesis approaches. We applied a standard ENU mutagenesis protocol to adult zebrafish deficient in the MMR gene msh6 and heterozygous controls to study the effect of MMR on ENU-induced DNA damage. Dose-dependent lethality was found to be similar for homozygous and heterozygous mutants, indicating that there is no difference in ENU resistance. Mutation discovery by high-throughput dideoxy resequencing of genomic targets in outcrossed progeny of the mutagenized fish did also not reveal any differences in germ line mutation frequency. These results may indicate that the maximum mutation load for zebrafish has been reached with the currently used, highly optimized ENU mutagenesis protocol. Alternatively, the MMR system in the zebrafish germ line may be saturated very rapidly, thereby having a limited effect on high-dose ENU mutagenesis.

Signaling through the TGF Beta-Activin Receptors ALK4/5/7 Regulates Testis Formation and Male Germ Cell Development

PubMed Central

Stringer, Jessica M.; van den Bergen, Jocelyn A.; Wilhelm, Dagmar; Sinclair, Andrew H.; Western, Patrick S.

2013-01-01

The developing testis provides an environment that nurtures germ cell development, ultimately ensuring spermatogenesis and fertility. Impacts on this environment are considered to underlie aberrant germ cell development and formation of germ cell tumour precursors. The signaling events involved in testis formation and male fetal germ cell development remain largely unknown. Analysis of knockout mice lacking single Tgfβ family members has indicated that Tgfβ's are not required for sex determination. However, due to functional redundancy, it is possible that additional functions for these ligands in gonad development remain to be discovered. Using FACS purified gonadal cells, in this study we show that the genes encoding Activin's, TGFβ's, Nodal and their respective receptors, are expressed in sex and cell type specific patterns suggesting particular roles in testis and germ cell development. Inhibition of signaling through the receptors ALK4, ALK5 and ALK7, and ALK5 alone, demonstrated that TGFβ signaling is required for testis cord formation during the critical testis-determining period. We also show that signaling through the Activin/NODAL receptors, ALK4 and ALK7 is required for promoting differentiation of male germ cells and their entry into mitotic arrest. Finally, our data demonstrate that Nodal is specifically expressed in male germ cells and expression of the key pluripotency gene, Nanog was significantly reduced when signaling through ALK4/5/7 was blocked. Our strategy of inhibiting multiple Activin/NODAL/TGFβ receptors reduces the functional redundancy between these signaling pathways, thereby revealing new and essential roles for TGFβ and Activin signaling during testis formation and male germ cell development. PMID:23342175

Production of Zebrafish Offspring from Cultured Female Germline Stem Cells

PubMed Central

Wong, Ten-Tsao; Tesfamichael, Abraham; Collodi, Paul

2013-01-01

Zebrafish female germline stem cell (FGSC) cultures were generated from a transgenic line of fish that expresses Neo and DsRed under the control of the germ cell specific promoter, ziwi [Tg(ziwi:neo);Tg(ziwi:DsRed)]. Homogeneous FGSC cultures were established by G418 selection and continued to express ziwi for more than 6 weeks along with the germ cell markers nanos3, dnd, dazl and vasa. A key component of the cell culture system was the use of a feeder cell line that was initiated from ovaries of a transgenic line of fish [Tg(gsdf:neo)] that expresses Neo controlled by the zebrafish gonadal soma derived factor (gsdf) promoter. The feeder cell line was selected in G418 and engineered to express zebrafish leukemia inhibitory factor (Lif), basic fibroblast growth factor (Fgf2) and glial-cell-line derived neurotrophic factor (Gdnf). These factors were shown to significantly enhance FGSC growth, survival and germline competency in culture. Results from cell transplantation experiments revealed that the cultured FGSCs were able to successfully colonize the gonad of sterile recipient fish and generate functional gametes. Up to 20% of surviving recipient fish that were injected with the cultured FGSCs were fertile and generated multiple batches of normal offspring for at least 6 months. The FGSC cultures will provide an in vitro system for studies of zebrafish germ cell growth and differentiation and their high frequency of germline transmission following transplantation could form the basis of a stem cell-mediated strategy for gene transfer and manipulation of the zebrafish genome. PMID:23671620

The Diversity of Nanos Expression in Echinoderm Embryos Supports Different Mechanisms in Germ Cell Specification

PubMed Central

Fresques, Tara; Swartz, S. Zachary; Juliano, Celina; Morino, Yoshiaki; Kikuchi, Mani; Akasaka, Koji; Wada, Hiroshi; Yajima, Mamiko; Wessel, Gary M.

2016-01-01

Specification of the germ cell lineage is required for sexual reproduction in all animals. However, the timing and mechanisms of germ cell specification is remarkably diverse in animal development. Echinoderms, such as sea urchins and sea stars, are excellent model systems to study the molecular and cellular mechanisms that contribute to germ cell specification. In several echinoderm embryos tested, the germ cell factor Vasa accumulates broadly during early development and is restricted after gastrulation to cells that contribute to the germ cell lineage. In the sea urchin, however, the germ cell factor Vasa is restricted to a specific lineage by the 32-cell stage. We therefore hypothesized that the germ cell specification program in the sea urchin/Euechinoid lineage has evolved to an earlier developmental time point. To test this hypothesis we determined the expression pattern of a second germ cell factor, Nanos, in four out of five extant echinoderm clades. Here we find that Nanos mRNA does not accumulate until the blastula stage or later during the development of all other echinoderm embryos except those that belong to the Echinoid lineage. Instead, Nanos is expressed in a restricted domain at the 32–128 cell stage in Echinoid embryos. Our results support the model that the germ cell specification program underwent a heterochronic shift in the Echinoid lineage. A comparison of Echinoid and non-Echinoid germ cell specification mechanisms will contribute to our understanding of how these mechanisms have changed during animal evolution. PMID:27402572

Extraction and demulsification of oil from wheat germ, barley germ, and rice bran using an aqueous enzymatic method

USDA-ARS?s Scientific Manuscript database

An aqueous enzymatic method was developed to extract oil from wheat germ. The parameters that influence oil yield were investigated, including wheat germ pretreatment, comparison of various industrial enzymes, pH, ratio of wheat germ to water, reaction time and demulsification. Pretreatment at 180ºC...

Endocarditis

MedlinePlus

Endocarditis Overview Endocarditis is an infection of the endocardium, which is the inner lining of your heart chambers and heart valves. Endocarditis generally occurs when bacteria, fungi or other germs ...

Modeling Radiation Effectiveness for Inactivation of Bacillus Spores

DTIC Science & Technology

2015-09-17

are the exosporium, the spore coat, the outer membrane, the cortex, the germ cell wall, the inner membrane, and the core. These are illustrated in...small amounts of carbohydrates and lipids. The 6 coat acts as the spore’s first line of defense against some chemical infiltration such as lytic enzymes...the spore as water makes up 48-57 percent of the cortex [2]. Immediately interior to the cortex is the germ cell wall which is also a peptidoglycan

Instruction at the Hopkins Marine Station

DTIC Science & Technology

1992-07-29

foI homtadcodnaio.. caronavirus nucleocapsid protein. wheat germ bial ~ ~ %~H2A (5), mussel sperm nuclear protein 03 [6), and man chromofsome...wvpi,~Tninev PM"p Johne HiWA~aa Unuw~rsaty &Dio of Medicine, Balw,,.vv, Manh land 21205 The two germ -line- specific Sp histione classes Treatment of...composit conical morphology of the male pronucleus- Mal, pro- serine-proline adjacent to two basic amino acids (lyo hucl*I inhibite’d with I nsMGDMAP

Histone modifications in the male germ line of Drosophila.

PubMed

Hennig, Wolfgang; Weyrich, Alexandra

2013-02-22

In the male germ line of Drosophila chromatin remains decondensed and highly transcribed during meiotic prophase until it is rapidly compacted. A large proportion of the cell cycle-regulated histone H3.1 is replaced by H3.3, a histone variant encoded outside the histone repeat cluster and not subject to cell cycle controlled expression. We investigated histone modification patterns in testes of D. melanogaster and D. hydei. In somatic cells of the testis envelope and in germ cells these modification patterns differ from those typically seen in eu- and heterochromatin of other somatic cells. During the meiotic prophase some modifications expected in active chromatin are not found or are found at low level. The absence of H4K16ac suggests that dosage compensation does not take place. Certain histone modifications correspond to either the cell cycle-regulated histone H3.1 or to the testis-specific variant H3.3. In spermatogonia we found H3K9 methylation in cytoplasmic histones, most likely corresponding to the H3.3 histone variant. Most histone modifications persist throughout the meiotic divisions. The majority of modifications persist until the early spermatid nuclei, and only a minority further persist until the final chromatin compaction stages before individualization of the spermatozoa. Histone modification patterns in the male germ line differ from expected patterns. They are consistent with an absence of dosage compensation of the X chromosome during the male meiotic prophase. The cell cycle-regulated histone variant H3.1 and H3.3, expressed throughout the cell cycle, also vary in their modification patterns. Postmeiotically, we observed a highly complex pattern of the histone modifications until late spermatid nuclear elongation stages. This may be in part due to postmeiotic transcription and in part to differential histone replacement during chromatin condensation.

Production of transgenic chickens using an avian retroviral vector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kopchick, J.; Mills, E.; Rosenblum C.

1987-05-01

The authors efforts to insert genes into the chicken germ line are dependent upon the ability of exogenous avian retroviruses to infect chicken germ cells. They have used a transformation defective Schmidt Ruppin A strain of Rous Sarcoma Virus (RSV-SRA) in their initial experiments. The general protocol involved generating RSV-SRA viremic female chickens (Go), which shed exogenous virus via the oviduct. As the fertilized egg passes through the oviduct, embryonic cells are exposed to the virus. If the germ cell precursors are infected by the virus, offspring (G1) should be generated which are capable of passing the viral DNA tomore » the next generation (G2). Fifteen viremic G1 males were selected for breeding and progeny testing. Since male chickens do not congenitally pass retroviruses through semen, production of viremic G2 offspring indicates germ line DNA transmission. This is confirmed by DNA analysis of the experimental chickens. Using a specific probe for exogenous retrovirus, they have detected the presence of RSV-SRA DNA in viremic chickens. Southern DNA analysis revealed junction fragments for RSV-SRA DNA in viremic G2 chickens, but not in non-viremic siblings. Furthermore, DNA isolated from various tissues of a viremic G2 chicken showed an identical DNA junction fragment pattern, indicating all tissues were derived from the same embryonic cell which contained integrated provirus. To date they have generated 50 transgenic chickens.« less

Ustiloxin G, a New Cyclopeptide Mycotoxin from Rice False Smut Balls.

PubMed

Wang, Xiaohan; Wang, Jian; Lai, Daowan; Wang, Weixuan; Dai, Jungui; Zhou, Ligang; Liu, Yang

2017-02-10

Ustiloxins were cyclopeptide mycotoxins from rice false smut balls (FSBs) that formed in rice spikelets infected by the fungal pathogen Ustilaginoidea virens . To investigate the chemical diversity of these metabolites and their bioactivities, one new cyclopeptide, ustiloxin G ( 1 ), together with four known congeners-ustiloxins A ( 2 ), B ( 3 ), D ( 4 ), and F ( 5 )-were isolated from water extract of rice FSBs. Their structures were elucidated by analyses of their physical and spectroscopic data, including ultraviolet spectrometry (UV), infrared spectroscopy (IR), 1D and 2D nuclear magnetic resonance (NMR), and high-resolution electrospray ionization-mass spectrometry (HR-ESI-MS). All the compounds were evaluated for their cytotoxic as well as radicle and germ elongation inhibitory activities. Ustiloxin B ( 3 ) showed the best activity against the cell line BGC-823 with an IC 50 value of 1.03 µM, while ustiloxin G ( 1 ) showed moderate activity against the cell lines A549 and A375 with IC 50 values of 36.5 µM and 22.5 µM, respectively. Ustiloxins A ( 2 ), B ( 3 ), and G ( 1 ) showed strong inhibition of radicle and germ elongation of rice seeds. When their concentrations were at 200 µg/mL, the inhibitory ratios of radicle and germ elongation were more than 90% and 50%, respectively, the same effect as that of positive control (glyphosate). They also induced abnormal swelling of the roots and germs of rice seedlings.

Hyperinsulinemic hypoglycemia evolving to gestational diabetes and diabetes mellitus in a family carrying the inactivating ABCC8 E1506K mutation.

PubMed

Vieira, Teresa C; Bergamin, Carla S; Gurgel, Lucimary C; Moisés, Regina S

2010-11-01

Congenital hyperinsulinism of infancy (CHI) is the most common cause of hypoglycemia in newborns and infants. Several molecular mechanisms are involved in the development of CHI, but the most common genetic defects are inactivating mutations of the ABCC8 or KCNJ11 genes. The classical treatment for CHI has been pancreatectomy that eventually leads to diabetes. More recently, conservative treatment has been attempted in some cases, with encouraging results. Whether or not the patients with heterozygous ABCC8 mutations submitted to conservative treatment may spontaneously develop type 2 diabetes in the long run, is a controversial issue. Here, we report a family carrying the dominant heterozygous germ line E1506K mutation in ABCC8 associated with persistent hypoglycemia in the newborn period and diabetes in adulthood. The mutation occurred as a de novo germ line mutation in the mother of the index patient. Her hypoglycemic symptoms as a child occurred after the fourth year of life and were very mild, but she developed glucose metabolism impairment in adulthood. On the other hand, in her daughter, the clinical manifestations of the disease occurred in the neonatal period and were more severe, leading to episodes of tonic-clonic seizures that were well controlled with octreotide or diazoxide. Our data corroborate the hypothesis that the dominant E1506K ABCC8 mutation, responsible for CHI, predisposes to the development of glucose intolerance and diabetes later in life. © 2009 John Wiley & Sons A/S.

Wnt signaling-mediated redox regulation maintains the germ line stem cell differentiation niche

PubMed Central

Wang, Su; Gao, Yuan; Song, Xiaoqing; Ma, Xing; Zhu, Xiujuan; Mao, Ying; Yang, Zhihao; Ni, Jianquan; Li, Hua; Malanowski, Kathryn E; Anoja, Perera; Park, Jungeun; Haug, Jeff; Xie, Ting

2015-01-01

Adult stem cells continuously undergo self-renewal and generate differentiated cells. In the Drosophila ovary, two separate niches control germ line stem cell (GSC) self-renewal and differentiation processes. Compared to the self-renewing niche, relatively little is known about the maintenance and function of the differentiation niche. In this study, we show that the cellular redox state regulated by Wnt signaling is critical for the maintenance and function of the differentiation niche to promote GSC progeny differentiation. Defective Wnt signaling causes the loss of the differentiation niche and the upregulated BMP signaling in differentiated GSC progeny, thereby disrupting germ cell differentiation. Mechanistically, Wnt signaling controls the expression of multiple glutathione-S-transferase family genes and the cellular redox state. Finally, Wnt2 and Wnt4 function redundantly to maintain active Wnt signaling in the differentiation niche. Therefore, this study has revealed a novel strategy for Wnt signaling in regulating the cellular redox state and maintaining the differentiation niche. DOI: http://dx.doi.org/10.7554/eLife.08174.001 PMID:26452202

The Geochemical Earth Reference Model (GERM)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Staudigel, H.; Albarede, F.; Shaw, H.

The Geochemical Earth Reference Model (GERM) initiative is a grass- roots effort with the goal of establishing a community consensus on a chemical characterization of the Earth, its major reservoirs, and the fluxes between them. Long term goal of GERM is a chemical reservoir characterization analogous to the geophysical effort of the Preliminary Reference Earth Model (PREM). Chemical fluxes between reservoirs are included into GERM to illuminate the long-term chemical evolution of the Earth and to characterize the Earth as a dynamic chemical system. In turn, these fluxes control geological processes and influence hydrosphere-atmosphere-climate dynamics. While these long-term goals aremore » clearly the focus of GERM, the process of establishing GERM itself is just as important as its ultimate goal. The GERM initiative is developed in an open community discussion on the World Wide Web (GERM home page is at http://www-ep.es.llnl. gov/germ/germ-home.html) that is mediated by a series of editors with responsibilities for distinct reservoirs and fluxes. Beginning with the original workshop in Lyons (March 1996) GERM is continued to be developed on the Internet, punctuated by workshops and special sessions at professional meetings. It is planned to complete the first model by mid-1997, followed by a call for papers for a February 1998 GERM conference in La Jolla, California.« less

A homozygous p53 R282W mutant human embryonic stem cell line generated using TALEN-mediated precise gene editing.

PubMed

Zhou, Ruoji; Xu, An; Wang, Donghui; Zhu, Dandan; Mata, Helen; Huo, Zijun; Tu, Jian; Liu, Mo; Mohamed, Alaa M T; Jewell, Brittany E; Gingold, Julian; Xia, Weiya; Rao, Pulivarthi H; Hung, Mien-Chie; Zhao, Ruiying; Lee, Dung-Fang

2018-03-01

The tumor suppressor gene TP53 is the most frequently mutated gene in human cancers. Many hot-spot mutations of TP53 confer novel functions not found in wild-type p53 and contribute to tumor development and progression. We report on the generation of a H1 human embryonic stem cell line carrying a homozygous TP53 R282W mutation using TALEN-mediated genome editing. The generated cell line demonstrates normal karyotype, maintains a pluripotent state, and is capable of generating a teratoma in vivo containing tissues from all three germ layers. Copyright © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.

Male Hypogonadism and Germ Cell Loss Caused by a Mutation in Polo-Like Kinase 4

PubMed Central

Harris, Rebecca M.; Weiss, Jeffrey

2011-01-01

The genetic etiologies of male infertility remain largely unknown. To identify genes potentially involved in spermatogenesis and male infertility, we performed genome-wide mutagenesis in mice with N-ethyl-N-nitrosourea and identified a line with dominant hypogonadism and patchy germ cell loss. Genomic mapping and DNA sequence analysis identified a novel heterozygous missense mutation in the kinase domain of Polo-like kinase 4 (Plk4), altering an isoleucine to asparagine at residue 242 (I242N). Genetic complementation studies using a gene trap line with disruption in the Plk4 locus confirmed that the putative Plk4 missense mutation was causative. Plk4 is known to be involved in centriole formation and cell cycle progression. However, a specific role in mammalian spermatogenesis has not been examined. PLK4 was highly expressed in the testes both pre- and postnatally. In the adult, PLK4 expression was first detected in stage VIII pachytene spermatocytes and was present through step 16 elongated spermatids. Because the homozygous Plk4I242N/I242N mutation was embryonic lethal, all analyses were performed using the heterozygous Plk4+/I242N mice. Testis size was reduced by 17%, and histology revealed discrete regions of germ cell loss, leaving only Sertoli cells in these defective tubules. Testis cord formation (embryonic day 13.5) was normal. Testis histology was also normal at postnatal day (P)1, but germ cell loss was detected at P10 and subsequent ages. We conclude that the I242N heterozygous mutation in PLK4 is causative for patchy germ cell loss beginning at P10, suggesting a role for PLK4 during the initiation of spermatogenesis. PMID:21791561

The diversity of nanos expression in echinoderm embryos supports different mechanisms in germ cell specification.

PubMed

Fresques, Tara; Swartz, Steven Zachary; Juliano, Celina; Morino, Yoshiaki; Kikuchi, Mani; Akasaka, Koji; Wada, Hiroshi; Yajima, Mamiko; Wessel, Gary M

2016-07-01

Specification of the germ cell lineage is required for sexual reproduction in all animals. However, the timing and mechanisms of germ cell specification is remarkably diverse in animal development. Echinoderms, such as sea urchins and sea stars, are excellent model systems to study the molecular and cellular mechanisms that contribute to germ cell specification. In several echinoderm embryos tested, the germ cell factor Vasa accumulates broadly during early development and is restricted after gastrulation to cells that contribute to the germ cell lineage. In the sea urchin, however, the germ cell factor Vasa is restricted to a specific lineage by the 32-cell stage. We therefore hypothesized that the germ cell specification program in the sea urchin/Euechinoid lineage has evolved to an earlier developmental time point. To test this hypothesis we determined the expression pattern of a second germ cell factor, Nanos, in four out of five extant echinoderm clades. Here we find that Nanos mRNA does not accumulate until the blastula stage or later during the development of all other echinoderm embryos except those that belong to the Echinoid lineage. Instead, Nanos is expressed in a restricted domain at the 32-128 cell stage in Echinoid embryos. Our results support the model that the germ cell specification program underwent a heterochronic shift in the Echinoid lineage. A comparison of Echinoid and non-Echinoid germ cell specification mechanisms will contribute to our understanding of how these mechanisms have changed during animal evolution. © 2016 Wiley Periodicals, Inc.

Identification of Potential Germ-Cell Mutagens

EPA Science Inventory

The existence of agents that can induce germ-cell mutations in experimental systems has been recognized since 1927 with the discovery of the ability of X-rays to induce such mutations in Drosophila. Various rodent-based germ-cell mutation assays have been developed, and ~50 germ...

Germ Cell-less Promotes Centrosome Segregation to Induce Germ Cell Formation.

PubMed

Lerit, Dorothy A; Shebelut, Conrad W; Lawlor, Kristen J; Rusan, Nasser M; Gavis, Elizabeth R; Schedl, Paul; Deshpande, Girish

2017-01-24

The primordial germ cells (PGCs) specified during embryogenesis serve as progenitors to the adult germline stem cells. In Drosophila, the proper specification and formation of PGCs require both centrosomes and germ plasm, which contains the germline determinants. Centrosomes are microtubule (MT)-organizing centers that ensure the faithful segregation of germ plasm into PGCs. To date, mechanisms that modulate centrosome behavior to engineer PGC development have remained elusive. Only one germ plasm component, Germ cell-less (Gcl), is known to play a role in PGC formation. Here, we show that Gcl engineers PGC formation by regulating centrosome dynamics. Loss of gcl leads to aberrant centrosome separation and elaboration of the astral MT network, resulting in inefficient germ plasm segregation and aborted PGC cellularization. Importantly, compromising centrosome separation alone is sufficient to mimic the gcl loss-of-function phenotypes. We conclude Gcl functions as a key regulator of centrosome separation required for proper PGC development. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Germ Cells Are Not Required to Establish the Female Pathway in Mouse Fetal Gonads

PubMed Central

Maatouk, Danielle M.; Mork, Lindsey; Hinson, Ashley; Kobayashi, Akio; McMahon, Andrew P.; Capel, Blanche

2012-01-01

The fetal gonad is composed of a mixture of somatic cell lineages and germ cells. The fate of the gonad, male or female, is determined by a population of somatic cells that differentiate into Sertoli or granulosa cells and direct testis or ovary development. It is well established that germ cells are not required for the establishment or maintenance of Sertoli cells or testis cords in the male gonad. However, in the agametic ovary, follicles do not form suggesting that germ cells may influence granulosa cell development. Prior investigations of ovaries in which pre-meiotic germ cells were ablated during fetal life reported no histological changes during stages prior to birth. However, whether granulosa cells underwent normal molecular differentiation was not investigated. In cases where germ cell loss occurred secondary to other mutations, transdifferentiation of granulosa cells towards a Sertoli cell fate was observed, raising questions about whether germ cells play an active role in establishing or maintaining the fate of granulosa cells. We developed a group of molecular markers associated with ovarian development, and show here that the loss of pre-meiotic germ cells does not disrupt the somatic ovarian differentiation program during fetal life, or cause transdifferentiation as defined by expression of Sertoli markers. Since we do not find defects in the ovarian somatic program, the subsequent failure to form follicles at perinatal stages is likely attributable to the absence of germ cells rather than to defects in the somatic cells. PMID:23091613

Intensified chemotherapy with stem-cell rescue in germ-cell tumors.

PubMed

Simonelli, M; Rosti, G; Banna, G L; Pedrazzoli, P

2012-04-01

Based on the high chemosensitivity of germ-cell tumors (GCTs), the concept of high-dose chemotherapy (HDCT) has been developed worldwide and investigated through many clinical trials. It has been carried out in different clinical settings, ranging from resistant or absolute refractory disease to chemosensitive relapse. HDCT with stem-cell support has been also explored as a part of first-line strategy for poor-prognosis patients. Our review summarized results from clinical trials evaluating the role of HDCT in patients with advanced GCTs. So far available data were obtained through a Medline search of English-language literature. Several phase II trials and retrospective series have shown a possible benefit for GCT patients with recurrent disease as well as in first-line setting. Despite these results, data derived from randomized phase III studies failed to demonstrate any survival advantage for HDCT over conventional chemotherapy. The role of HDCT in GCTs remains controversial. We need new prospective studies based on prognostic factors with multiple transplants of carboplatin and etoposide as the preferred high dose regimen. At present, based mainly on retrospective and phase II studies, HDCT may represent a therapeutic option for patients with primary refractory disease or for those with a second or further relapse.

[Radiation-induced intracranial osteosarcoma after radiation for acute lymphocytic leukemia associated with Li-Fraumeni syndrome].

PubMed

Yoshimura, Junichi; Natsumeda, Manabu; Nishihira, Yasushi; Nishiyama, Kenichi; Saito, Akihiko; Okamoto, Kouichirou; Takahashi, Hitoshi; Fujii, Yukihiko

2013-06-01

A 28-year-old man presented with osteosarcoma of the occipital bone 16 years after 24 Gy of craniospinal irradiation for acute lymphocytic leukemia. The tumor had both intra- and extra-cranial components. However, the affected skull appeared to be normal on imaging because of permeative infiltration by the tumor. Subtotal resection was achieved and the tumor was verified histologically as an osteosarcoma. The residual tumor soon showed remarkable enlargement and disseminated to the spinal cord. Both of the enlarged and disseminated tumor masses were treated by surgical intervention and chemotherapy. However, the patient deteriorated due to the tumor regrowth and died 11 months after the initial diagnosis. This patient had previously developed a leukemia, a colon cancer, a rectal cancer and a hepatocellular carcinoma. His brother also died of leukemia. The patient had a heterozygous TP53 germ-line mutation of codon 248 in the exon 7. In conclusion, we consider the present tumor to be a rare example of radiation-induced skull osteosarcoma in a member of the cancer-prone family with TP53 germ-line mutation which is associated with Li-Fraumeni syndrome.

Cabazitaxel overcomes cisplatin resistance in germ cell tumour cells.

PubMed

Gerwing, Mirjam; Jacobsen, Christine; Dyshlovoy, Sergey; Hauschild, Jessica; Rohlfing, Tina; Oing, Christoph; Venz, Simone; Oldenburg, Jan; Oechsle, Karin; Bokemeyer, Carsten; von Amsberg, Gunhild; Honecker, Friedemann

2016-09-01

Cisplatin-based chemotherapy is highly effective in metastasized germ cell tumours (GCT). However, 10-30 % of patients develop resistance to cisplatin, requiring salvage therapy. We investigated the in vitro activity of paclitaxel and the novel taxane cabazitaxel in cisplatin-sensitive and -resistant GCT cell lines. In vitro activity of paclitaxel and cabazitaxel was determined by proliferation assays, and mode of action of cabazitaxel was assessed by western blotting and two screening approaches, i.e. whole proteome analysis and a human apoptosis array. Activity of paclitaxel and cabazitaxel was not affected by cisplatin resistance, suggesting that there is no cross-resistance between these agents in vitro. Cabazitaxel treatment showed a strong inhibitory effect on colony formation capacity. Cabazitaxel induced classical apoptosis in all cell lines, reflected by cleavage of PARP and caspase 3, without inducing specific changes in the cell cycle distribution. Using the proteomic and human apoptosis array screening approaches, differential regulation of several proteins, including members of the bcl-2 family, was found, giving first insights into the mode of action of cabazitaxel in GCT. Cabazitaxel shows promising in vitro activity in GCT cells, independent of levels of cisplatin resistance.

Transgene expression of green fluorescent protein and germ line transmission in cloned pigs derived from in vitro transfected adult fibroblasts.

PubMed

Brunetti, Dario; Perota, Andrea; Lagutina, Irina; Colleoni, Silvia; Duchi, Roberto; Calabrese, Fiorella; Seveso, Michela; Cozzi, Emanuele; Lazzari, Giovanna; Lucchini, Franco; Galli, Cesare

2008-12-01

The pig represents the xenogeneic donor of choice for future organ transplantation in humans for anatomical and physiological reasons. However, to bypass several immunological barriers, strong and stable human genes expression must occur in the pig's organs. In this study we created transgenic pigs using in vitro transfection of cultured cells combined with somatic cell nuclear transfer (SCNT) to evaluate the ubiquitous transgene expression driven by pCAGGS vector in presence of different selectors. pCAGGS confirmed to be a very effective vector for ubiquitous transgene expression, irrespective of the selector that was used. Green fluorescent protein (GFP) expression observed in transfected fibroblasts was also maintained after nuclear transfer, through pre- and postimplantation development, at birth and during adulthood. Germ line transmission without silencing of the transgene was demonstrated. The ubiquitous expression of GFP was clearly confirmed in several tissues including endothelial cells, thus making it a suitable vector for the expression of multiple genes relevant to xenotransplantation where tissue specificity is not required. Finally cotransfection of green and red fluorescence protein transgenes was performed in fibroblasts and after nuclear transfer blastocysts expressing both fluorescent proteins were obtained.

Unregulated smooth-muscle myosin in human intestinal neoplasia.

PubMed

Alhopuro, Pia; Phichith, Denis; Tuupanen, Sari; Sammalkorpi, Heli; Nybondas, Miranda; Saharinen, Juha; Robinson, James P; Yang, Zhaohui; Chen, Li-Qiong; Orntoft, Torben; Mecklin, Jukka-Pekka; Järvinen, Heikki; Eng, Charis; Moeslein, Gabriela; Shibata, Darryl; Houlston, Richard S; Lucassen, Anneke; Tomlinson, Ian P M; Launonen, Virpi; Ristimäki, Ari; Arango, Diego; Karhu, Auli; Sweeney, H Lee; Aaltonen, Lauri A

2008-04-08

A recent study described a recessive ATPase activating germ-line mutation in smooth-muscle myosin (smmhc/myh11) underlying the zebrafish meltdown (mlt) phenotype. The mlt zebrafish develops intestinal abnormalities reminiscent of human Peutz-Jeghers syndrome (PJS) and juvenile polyposis (JP). To examine the role of MYH11 in human intestinal neoplasia, we searched for MYH11 mutations in patients with colorectal cancer (CRC), PJS and JP. We found somatic protein-elongating frameshift mutations in 55% of CRCs displaying microsatellite instability and in the germ-line of one individual with PJS. Additionally, two somatic missense mutations were found in one microsatellite stable CRC. These two missense mutations, R501L and K1044N, and the frameshift mutations were functionally evaluated. All mutations resulted in unregulated molecules displaying constitutive motor activity, similar to the mutant myosin underlying mlt. Thus, MYH11 mutations appear to contribute also to human intestinal neoplasia. Unregulated MYH11 may affect the cellular energy balance or disturb cell lineage decisions in tumor progenitor cells. These data challenge our view on MYH11 as a passive differentiation marker functioning in muscle contraction and add to our understanding of intestinal neoplasia.

Extraction and characterization of corn germ proteins

USDA-ARS?s Scientific Manuscript database

Our study was conducted to develop methods to extract corn germ protein economically and characterize and identify potential applications of the recovered protein. Protein was extracted from both wet germ and finished (dried) germ using 0.1M NaCl as solvent. The method involved homogenization, sti...

Inactivation of the F4/80 glycoprotein in the mouse germ line.

PubMed

Schaller, Evelyne; Macfarlane, Alison J; Rupec, Rudolf A; Gordon, Siamon; McKnight, Andrew J; Pfeffer, Klaus

2002-11-01

Macrophages play a crucial role in the defense against pathogens. Distinct macrophage populations can be defined by the expression of restricted cell surface proteins. Resident tissue macrophages, encompassing Kupffer cells of the liver and red pulp macrophages of the spleen, characteristically express the F4/80 molecule, a cell surface glycoprotein related to the seven transmembrane-spanning family of hormone receptors. In this study, gene targeting was used to simultaneously inactivate the F4/80 molecule in the germ line of the mouse and to produce a mouse line that expresses the Cre recombinase under the direct control of the F4/80 promoter (F4/80-Cre knock-in). F4/80-deficient mice are healthy and fertile. Macrophage populations in tissues can develop in the absence of F4/80 expression. Functional analysis revealed that the generation of T-cell-independent B-cell responses and macrophage antimicrobial defense after infection with Listeria monocytogenes are not impaired in the absence of F4/80. Interestingly, tissues of F4/80-deficient mice could not be labeled with anti-BM8, another macrophage subset-specific marker with hitherto undefined molecular antigenic structure. Recombinant expression of a F4/80 cDNA in heterologous cells confirmed this observation, indicating that the targets recognized by the F4/80 and BM8 monoclonal antibodies are identical.

Extracranial Germ Cell Tumors—Patient Version

Cancer.gov

Extracranial germ cell tumors are tumors that develop from germ cells (fetal cells that give rise to sperm and eggs) and can form in many parts of the body. They are most common in teenagers and can often be cured. Start here to find information on extracranial germ cell tumors treatment.

Stage-dependent piRNAs in chicken implicated roles in modulating male germ cell development.

PubMed

Chang, Kai-Wei; Tseng, Yen-Tzu; Chen, Yi-Chen; Yu, Chih-Yun; Liao, Hung-Fu; Chen, Yi-Chun; Tu, Yu-Fan Evan; Wu, Shinn-Chih; Liu, I-Hsuan; Pinskaya, Marina; Morillon, Antonin; Pain, Bertrand; Lin, Shau-Ping

2018-06-01

The PIWI/piRNA pathway is a conserved machinery important for germ cell development and fertility. This piRNA-guided molecular machinery is best known for repressing derepressed transposable elements (TE) during epigenomic reprogramming. The extent to which piRNAs are involved in modulating transcripts beyond TEs still need to be clarified, and it may be a stage-dependent event. We chose chicken germline as a study model because of the significantly lower TE complexity in the chicken genome compared to mammalian species. We generated high-confidence piRNA candidates in various stages across chicken germline development by 3'-end-methylation-enriched small RNA sequencing and in-house bioinformatics analysis. We observed a significant developmental stage-dependent loss of TE association and a shifting of the ping-pong cycle signatures. Moreover, the stage-dependent reciprocal abundance of LINE retrotransposons, CR1-C, and its associated piRNAs implicated the developmental stage-dependent role of piRNA machinery. The stage dependency of piRNA expression and its potential functions can be better addressed by analyzing the piRNA precursors/clusters. Interestingly, the new piRNA clusters identified from embryonic chicken testes revealed evolutionary conservation between chickens and mammals, which was previously thought to not exist. In this report, we provided an original chicken RNA resource and proposed an analytical methodology that can be used to investigate stage-dependent changes in piRNA compositions and their potential roles in TE regulation and beyond, and also revealed possible conserved functions of piRNAs in developing germ cells.

Isolation of new polar granule components in Drosophila reveals P body and ER associated proteins

PubMed Central

Thomson, Travis; Liu, Niankun; Arkov, Alexey; Lehmann, Ruth; Lasko, Paul

2008-01-01

Germ plasm, a specialized cytoplasm present at the posterior of the early Drosophila embryo, is necessary and sufficient for germ cell formation. Germ plasm is rich in mitochondria and contains electron dense structures called polar granules. To identify novel polar granule components we isolated proteins that associate in early embryos with Vasa (VAS) and Tudor (TUD), two known polar granule associated molecules. We identified Maternal expression at 31B (ME31B), eIF4A, Aubergine (AUB) and Transitional Endoplasmic Reticulum 94 (TER94) as components of both VAS and TUD complexes and confirmed their localization to polar granules by immuno-electron microscopy. ME31B, eIF4A and AUB are also present in processing (P) bodies, suggesting that polar granules, which are necessary for germ line formation, might be related to P bodies. Our recovery of ER associated proteins TER94 and ME31B confirms that polar granules are closely linked to the translational machinery and to mRNP assembly. PMID:18590813

A role for Lin28 in primordial germ cell development and germ cell malignancy

PubMed Central

West, Jason A.; Viswanathan, Srinivas R.; Yabuuchi, Akiko; Cunniff, Kerianne; Takeuchi, Ayumu; Park, In-Hyun; Sero, Julia E.; Zhu, Hao; Perez-Atayde, Antonio; Frazier, A. Lindsay; Surani, M. Azim; Daley, George Q.

2009-01-01

The rarity and inaccessibility of the earliest primordial germ cells (PGCs) in the mouse embryo thwarts efforts to investigate molecular mechanisms of germ cell specification. Stella marks the minute founder population of the germ lineage1,2. Here we differentiate mouse embryonic stem cells (ESCs) carrying a Stella transgenic reporter into putative PGCs in vitro. The Stella+ cells possess a transcriptional profile similar to embryo-derived PGCs, and like their counterparts in vivo, lose imprints in a time-dependent manner. Using inhibitory RNAs to screen candidate genes for effects on the development of Stella+ cells in vitro, we discovered that Lin28, a negative regulator of let-7 microRNA processing3-6, is essential for proper PGC development. We further show that Blimp1, a let-7 target and a master regulator of PGC specification7-9, can rescue the effect of Lin28-deficiency during PGC development, thereby establishing a mechanism of action for Lin28 during PGC specification. Over-expression of Lin28 promotes formation of Stella+ cells in vitro and PGCs in chimeric embryos, and is associated with human germ cell tumours. The differentiation of putative PGCs from ESCs in vitro recapitulates the early stages of gamete development in vivo, and provides an accessible system for discovering novel genes involved in germ cell development and malignancy. PMID:19578360

Germ Line IgM Is Sufficient, but Not Required, for Antibody-Mediated Alphavirus Clearance from the Central Nervous System.

PubMed

Nilaratanakul, Voraphoj; Chen, Jie; Tran, Oanh; Baxter, Victoria K; Troisi, Elizabeth M; Yeh, Jane X; Griffin, Diane E

2018-04-01

Sindbis virus (SINV) infection of neurons in the brain and spinal cord in mice provides a model system for investigating recovery from encephalomyelitis and antibody-mediated clearance of virus from the central nervous system (CNS). To determine the roles of IgM and IgG in recovery, we compared the responses of immunoglobulin-deficient activation-induced adenosine deaminase-deficient (AID -/- ), secretory IgM-deficient (sIgM -/- ), and AID -/- sIgM -/- double-knockout (DKO) mice with those of wild-type (WT) C57BL/6 mice for disease, clearance of infectious virus and viral RNA from brain and spinal cord, antibody responses, and B cell infiltration into the CNS. Because AID is essential for immunoglobulin class switch recombination and somatic hypermutation, AID -/- mice produce only germ line IgM, while sIgM -/- mice secrete IgG but no IgM and DKO mice produce no secreted immunoglobulin. After intracerebral infection with the TE strain of SINV, most mice recovered. Development of neurologic disease occurred slightly later in sIgM -/- mice, but disease severity, weight loss, and survival were similar between the groups. AID -/- mice produced high levels of SINV-specific IgM, while sIgM -/- mice produced no IgM and high levels of IgG2a compared to WT mice. All mice cleared infectious virus from the spinal cord, but DKO mice failed to clear infectious virus from brain and had higher levels of viral RNA in the CNS late after infection. The numbers of infected cells and the amount of cell death in brain were comparable. We conclude that antibody is required and that either germ line IgM or IgG is sufficient for clearance of virus from the CNS. IMPORTANCE Mosquito-borne alphaviruses that infect neurons can cause fatal encephalomyelitis. Recovery requires a mechanism for the immune system to clear virus from infected neurons without harming the infected cells. Antiviral antibody has previously been shown to be a noncytolytic means for alphavirus clearance. Antibody-secreting cells enter the nervous system after infection and produce antiviral IgM before IgG. Clinical studies of human viral encephalomyelitis suggest that prompt production of IgM is associated with recovery, but it was not known whether IgM is effective for clearance. Our studies used mice deficient in production of IgM, IgG, or both to characterize the antibody necessary for alphavirus clearance. All mice developed similar signs of neurologic disease and recovered from infection. Antibody was necessary for virus clearance from the brain, and either early germ line IgM or IgG was sufficient. These studies support the clinical observation that prompt production of antiviral antibody is a determinant of outcome. Copyright © 2018 American Society for Microbiology.

COX-1 Suppression and Follicle Depletion in the Etiology of Menopause-Associated Ovarian Cancer

DTIC Science & Technology

2008-10-01

form (8), and cause growth inhibition and apoptosis in ovarian cancer cell lines (9). However, the link between morphological inhibition and...of the c-kit receptor. Genes Dev 1990;4:390-400. 2. Mintz B. Embryological development of primordial germ-cells in the mouse: influence of a new...708–14. 12 Rodriguez GC, Walmer DK, Cline M, et al. Effect of progestin on the ovarian epithelium of macaques: cancer prevention through apoptosis

Extraction and functional properties of non-zein proteins in corn germ from wet-milling

USDA-ARS?s Scientific Manuscript database

This study was conducted to develop methods of extracting corn germ protein and characterize and identify potential applications of the recovered protein. Protein was extracted from both wet germ and finished (dried) germ using 0.1M NaCl as solvent. The method involved homogenization, stirring, cent...

Chromatin associated Sin3A is essential for male germ cell lineage in the mouse

PubMed Central

Pellegrino, Jessica; Castrillon, Diego H.; David, Gregory

2012-01-01

Spermatogenesis is a complex process that requires coordinated proliferation and differentiation of male germ cells. The molecular events that dictate this process are largely unknown, but are likely to involve highly regulated transcriptional control. In this study, we investigate the contribution of chromatin associated Sin3A in mouse germ cell lineage development. Genetic inactivation of Sin3A in the male germline leads to sterility that results from the early and penetrant apoptotic death observed in Sin3A-deleted germ cells, coincident with the reentry in mitosis. Sin3A-deleted testes exhibit a Sertoli-cell only phenotype, consistent with the absolute requirement for Sin3A in germ cells’ development and/or viability. Interestingly, transcripts analysis revealed that the expression program of Sertoli cells is altered upon inactivation of Sin3A in germ cells. These studies identified a central role for the mammalian Sin3-HDAC complex in the germ cell lineage, and point to an exquisite transcriptional crosstalk between germ cells and their niche to support fertility in mammals. PMID:22820070

From what should we protect future generations: germ-line therapy or genetic screening?

PubMed

Mallia, Pierre; ten Have, Henk

2003-01-01

This paper discusses the issue of whether we have responsibilities to future generations with respect to genetic screening, including for purposes of selective abortion or discard. Future generations have been discussed at length among scholars. The concept of 'Guardian for Future Generations' is tackled and its main criticisms discussed. Whilst germ-line cures, it is argued, can only affect family trees, genetic screening and testing can have wider implications. If asking how this may affect future generations is a legitimate question and since we indeed make retrospective moral judgements, it would be wise to consider that future generations will make the same retrospective judgements on us. Moreover such technologies affect present embryos to which we indeed can be considered to have an obligation.

Ustiloxin G, a New Cyclopeptide Mycotoxin from Rice False Smut Balls

PubMed Central

Wang, Xiaohan; Wang, Jian; Lai, Daowan; Wang, Weixuan; Dai, Jungui; Zhou, Ligang; Liu, Yang

2017-01-01

Ustiloxins were cyclopeptide mycotoxins from rice false smut balls (FSBs) that formed in rice spikelets infected by the fungal pathogen Ustilaginoidea virens. To investigate the chemical diversity of these metabolites and their bioactivities, one new cyclopeptide, ustiloxin G (1), together with four known congeners—ustiloxins A (2), B (3), D (4), and F (5)—were isolated from water extract of rice FSBs. Their structures were elucidated by analyses of their physical and spectroscopic data, including ultraviolet spectrometry (UV), infrared spectroscopy (IR), 1D and 2D nuclear magnetic resonance (NMR), and high-resolution electrospray ionization-mass spectrometry (HR-ESI-MS). All the compounds were evaluated for their cytotoxic as well as radicle and germ elongation inhibitory activities. Ustiloxin B (3) showed the best activity against the cell line BGC-823 with an IC50 value of 1.03 µM, while ustiloxin G (1) showed moderate activity against the cell lines A549 and A375 with IC50 values of 36.5 µM and 22.5 µM, respectively. Ustiloxins A (2), B (3), and G (1) showed strong inhibition of radicle and germ elongation of rice seeds. When their concentrations were at 200 µg/mL, the inhibitory ratios of radicle and germ elongation were more than 90% and 50%, respectively, the same effect as that of positive control (glyphosate). They also induced abnormal swelling of the roots and germs of rice seedlings. PMID:28208606

Epigenome regulation during germ cell specification and development from pluripotent stem cells.

PubMed

Kurimoto, Kazuki; Saitou, Mitinori

2018-06-13

Germ cells undergo epigenome reprogramming for proper development of the next generation. The realization of germ cell derivation from human and mouse pluripotent stem cells offers unprecedented opportunity for investigation of germline development. Primordial germ cells reconstituted in vitro (PGC-like cells [PGCLCs]) show progressive dilution of genomic DNA methylation, tightly linked with chromatin remodeling, during their specification. PGCLCs can be further expanded by plane culture, allowing maintenance of the gene-expression profiles of early PGCs and continuance of the DNA methylation erasure, thereby establishing an epigenetic `blank slate'. PGCLCs undergo further epigenome regulation to acquire the male or female fates. These findings will provide a foundation for basic germ cell biology and for in-depth evaluations of in vitro gametogenesis. Copyright © 2018 Elsevier Ltd. All rights reserved.

On the role of germ cells in mammalian gonad development: quiet passengers or back-seat drivers?

PubMed

Rios-Rojas, Clarissa; Bowles, Josephine; Koopman, Peter

2015-04-01

In addition to their role as endocrine organs, the gonads nurture and protect germ cells, and regulate the formation of gametes competent to convey the genome to the following generation. After sex determination, gonadal somatic cells use several known signalling pathways to direct germ cell development. However, the extent to which germ cells communicate back to the soma, the molecular signals they use to do so and the significance of any such signalling remain as open questions. Herein, we review findings arising from the study of gonadal development and function in the absence of germ cells in a range of organisms. Most published studies support the view that germ cells are unimportant for foetal gonadal development in mammals, but later become critical for stabilisation of gonadal function and somatic cell phenotype. However, the lack of consistency in the data, and clear differences between mammals and other vertebrates and invertebrates, suggests that the story may not be so simple and would benefit from more careful analysis using contemporary molecular, cell biology and imaging tools. © 2015 Society for Reproduction and Fertility.

Lin28a regulates germ cell pool size and fertility

PubMed Central

Shinoda, Gen; de Soysa, T. Yvanka; Seligson, Marc T.; Yabuuchi, Akiko; Fujiwara, Yuko; Huang, Pei Yi; Hagan, John P.; Gregory, Richard I.; Moss, Eric G.; Daley, George Q.

2013-01-01

Overexpression of LIN28A is associated with human germ cell tumors and promotes primordial germ cell (PGC) development from embryonic stem cells in vitro and in chimeric mice. Knockdown of Lin28a inhibits PGC development in vitro, but how constitutional Lin28a deficiency affects the mammalian reproductive system in vivo remains unknown. Here, we generated Lin28a knockout (KO) mice and found that Lin28a deficiency compromises the size of the germ cell pool in both males and females by affecting PGC proliferation during embryogenesis. Interestingly however, in Lin28a KO males the germ cell pool partially recovers during postnatal expansion, while fertility remains impaired in both males and females mated to wild type mice. Embryonic overexpression of let-7, a microRNA negatively regulated by Lin28a, reduces the germ cell pool, corroborating the role of the Lin28a/let-7 axis in regulating the germ lineage. PMID:23378032

Etoposide damages female germ cells in the developing ovary.

PubMed

Stefansdottir, Agnes; Johnston, Zoe C; Powles-Glover, Nicola; Anderson, Richard A; Adams, Ian R; Spears, Norah

2016-08-11

As with many anti-cancer drugs, the topoisomerase II inhibitor etoposide is considered safe for administration to women in the second and third trimesters of pregnancy, but assessment of effects on the developing fetus have been limited. The purpose of this research was to examine the effect of etoposide on germ cells in the developing ovary. Mouse ovary tissue culture was used as the experimental model, thus allowing us to examine effects of etoposide on all stages of germ cell development in the same way, in vitro. Fetal ovaries from embryonic day 13.5 CD1 mice or neonatal ovaries from postnatal day 0 CD1 mice were cultured with 50-150 ng ml(-1) or 50-200 ng ml(-1) etoposide respectively, concentrations that are low relative to that in patient serum. When fetal ovaries were treated prior to follicle formation, etoposide resulted in dose-dependent damage, with 150 ng ml(-1) inducing a near-complete absence of healthy follicles. In contrast, treatment of neonatal ovaries, after follicle formation, had no effect on follicle numbers and only a minor effect on follicle health, even at 200 ng ml(-1). The sensitivity of female germ cells to etoposide coincided with topoisomerase IIα expression: in the developing ovary of both mouse and human, topoisomerase IIα was expressed in germ cells only prior to follicle formation. Exposure of pre-follicular ovaries, in which topoisomerase IIα expression was germ cell-specific, resulted in a near-complete elimination of germ cells prior to follicle formation, with the remaining germ cells going on to form unhealthy follicles by the end of culture. In contrast, exposure to follicle-enclosed oocytes, which no longer expressed topoisomerase IIα in the germ cells, had no effect on total follicle numbers or health, the only effect seen specific to transitional follicles. Results indicate the potential for adverse effects on fetal ovarian development if etoposide is administered to pregnant women when germ cells are not yet enclosed within ovarian follicles, a process that starts at approximately 17 weeks gestation and is only complete towards the end of pregnancy.

Oral Health: A Window to Your Overall Health

MedlinePlus

... might contribute to various diseases and conditions, including: Endocarditis. Endocarditis is an infection of the inner lining of your heart (endocardium). Endocarditis typically occurs when bacteria or other germs from ...

Misexpression of cyclin D1 in embryonic germ cells promotes testicular teratoma initiation

PubMed Central

Lanza, Denise G.; Dawson, Emily P.; Rao, Priya; Heaney, Jason D.

2016-01-01

ABSTRACT Testicular teratomas result from anomalies in embryonic germ cell development. In the 129 family of inbred mouse strains, teratomas arise during the same developmental period that male germ cells normally enter G1/G0 mitotic arrest and female germ cells initiate meiosis (the mitotic:meiotic switch). Dysregulation of this switch associates with teratoma susceptibility and involves three germ cell developmental abnormalities seemingly critical for tumor initiation: delayed G1/G0 mitotic arrest, retention of pluripotency, and misexpression of genes normally restricted to embryonic female and adult male germ cells. One misexpressed gene, cyclin D1 (Ccnd1), is a known regulator of cell cycle progression and an oncogene in many tissues. Here, we investigated whether Ccnd1 misexpression in embryonic germ cells is a determinant of teratoma susceptibility in mice. We found that CCND1 localizes to teratoma-susceptible germ cells that fail to enter G1/G0 arrest during the mitotic:meiotic switch and is the only D-type cyclin misexpressed during this critical developmental time frame. We discovered that Ccnd1 deficiency in teratoma-susceptible mice significantly reduced teratoma incidence and suppressed the germ cell proliferation and pluripotency abnormalities associated with tumor initiation. Importantly, Ccnd1 expression was dispensable for somatic cell development and male germ cell specification and maturation in tumor-susceptible mice, implying that the mechanisms by which Ccnd1 deficiency reduced teratoma incidence were germ cell autonomous and specific to tumorigenesis. We conclude that misexpression of Ccnd1 in male germ cells is a key component of a larger pro-proliferative program that disrupts the mitotic:meiotic switch and predisposes 129 inbred mice to testicular teratocarcinogenesis. PMID:26901436

Childhood Central Nervous System Germ Cell Tumors Treatment (PDQ®)—Patient Version

Cancer.gov

Childhood central nervous system (CNS) germ cell tumors form from germ cells (a type of cell that forms as a fetus develops and later becomes sperm in the testicles or eggs in the ovaries). Learn about the signs, tests to diagnose, and treatment of pediatric germ cell tumors in the brain in this expert-reviewed summary.

Recurrent Infections May Signal Immunodeficiencies

MedlinePlus

... FAAAAI Your immune system is constantly on the defense-fighting germs that could cause infections. Sometimes the “ ... produce. Did You Know? • The first lines of defense against infection are your skin and the membranes ...

Cloned cows with short telomeres deliver healthy offspring with normal-length telomeres.

PubMed

Miyashita, Norikazu; Kubo, Yasuaki; Yonai, Miharu; Kaneyama, Kanako; Saito, Norio; Sawai, Ken; Minamihashi, Akira; Suzuki, Toshiyuki; Kojima, Toshiyuki; Nagai, Takashi

2011-10-01

Dolly, the first mammal cloned from a somatic cell, had shorter telomeres than age-matched controls and died at an early age because of disease. To investigate longevity and lifetime performance in cloned animals, we produced cloned cows with short telomeres using oviductal epithelial cells as donor cells. At 5 years of age, despite the presence of short telomeres, all cloned cows delivered multiple healthy offspring following artificial insemination with conventionally processed spermatozoa from noncloned bulls, and their milk production was comparable to that of donor cows. Moreover, this study revealed that the offspring had normal-length telomeres in their leukocytes and major organs. Thus, cloned animals have normal functional germ lines, and therefore germ line function can completely restore telomere lengths in clone gametes by telomerase activity, resulting in healthy offspring with normal-length telomeres.

piRNA-mediated transposon regulation and the germ-line mutation rate in Drosophila melanogaster males.

PubMed

Simmons, Michael J; Peterson, Mark P; Thorp, Michael W; Buschette, Jared T; DiPrima, Stephanie N; Harter, Christine L; Skolnick, Matthew J

2015-03-01

Transposons, especially retrotransposons, are abundant in the genome of Drosophila melanogaster. These mobile elements are regulated by small RNAs that interact with the Piwi family of proteins-the piwi-interacting or piRNAs. The Piwi proteins are encoded by the genes argonaute3 (ago3), aubergine (aub), and piwi. Heterochromatin Protein 1 (HP1), a chromatin-organizing protein encoded by the Suppressor of variegation 205 [Su(var)205] gene, also plays a role in this regulation. To assess the mutational impact of weakening the system for transposon regulation, we measured the frequency of recessive X-linked lethal mutations occurring in the germ lines of males from stocks that were heterozygous for mutant alleles of the ago3, aub, piwi, or Su(var)205 genes. These mutant alleles are expected to deplete the wild-type proteins encoded by these genes by as much as 50%. The mutant alleles of piwi and Su(var)205 significantly increased the X-linked lethal mutation frequency, whereas the mutant alleles of ago3 did not. An increased mutation frequency was also observed in males from one of two mutant aub stocks, but this increase may not have been due to the aub mutant. The increased mutation frequency caused by depleting Piwi or HP1suggests that chromatin-organizing proteins play important roles in minimizing the germ-line mutation rate, possibly by stabilizing the structure of the heterochromatin in which many transposons are situated. Copyright © 2015 Elsevier B.V. All rights reserved.

In Vitro Cytotoxicity of Nanoparticles in Mammalian Germline Stem Cells

PubMed Central

Braydich-Stolle, Laura; Hussain, Saber; Schlager, John J.; Hofmann, Marie-Claude

2010-01-01

Gametogenesis is a complex biological process that is particularly sensitive to environmental insults such as chemicals. Many chemicals have a negative impact on the germline, either by directly affecting the germ cells, or indirectly through their action on the somatic nursing cells. Ultimately, these effects can inhibit fertility, and they may have negative consequences for the development of the offspring. Recently, nanomaterials such as nanotubes, nanowires, fullerene derivatives (buckyballs), and quantum dots have received enormous national attention in the creation of new types of analytical tools for biotechnology and the life sciences. Despite the wide application of nanomaterials, there is a serious lack of information concerning their impact on human health and the environment. Thus, there are limited studies available on toxicity of nanoparticles for risk assessment of nanomaterials. The purpose of this study was to assess the suitability of a mouse spermatogonial stem cell line as a model to assess nanotoxicity in the male germline in vitro. The effects of different types of nanoparticles on these cells were evaluated by light microscopy, and by cell proliferation and standard cytotoxicity assays. Our results demonstrate a concentration-dependent toxicity for all types of particles tested, whereas the corresponding soluble salts had no significant effect. Silver nanoparticles were the most toxic while molybdenum trioxide (MoO3) nanoparticles were the least toxic. Our results suggest that this cell line provides a valuable model with which to assess the cytotoxicity of nanoparticles in the germ line in vitro. PMID:16014736

Tissue-Specific Methylation of Long Interspersed Nucleotide Element-1 of Homo Sapiens (L1Hs) During Human Embryogenesis and Roles in Neural Tube Defects.

PubMed

Wang, L; Chang, S; Guan, J; Shangguan, S; Lu, X; Wang, Z; Wu, L; Zou, J; Zhao, H; Bao, Y; Qiu, Z; Niu, B; Zhang, T

2015-01-01

Epigenetic regulation of long interspersed nucleotide element-1 (LINE-1) retrotransposition events plays crucial roles during early development. Previously we showed that LINE-1 hypomethylation in neuronal tissues is associated with pathogenesis of neural tube defect (NTD). Herein, we further evaluated LINE-1 Homo sapiens (L1Hs) methylation in tissues derived from three germ layers of stillborn NTD fetuses, to define patterns of tissue specific methylation and site-specific hypomethylation at CpG sites within an L1Hs promoter region. Stable, tissue-specific L1Hs methylation patterns throughout three germ layer lineages of the fetus, placenta, and maternal peripheral blood were observed. Samples from maternal peripheral blood exhibited the highest level of L1Hs methylation (64.95%) and that from placenta showed the lowest (26.82%). Between samples from NTDs and controls, decrease in L1Hs methylation was only significant in NTD-affected brain tissue at 7.35%, especially in females (8.98%). L1Hs hypomethylation in NTDs was also associated with a significant increase in expression level of an L1Hs-encoded transcript in females (r = -0.846, p = 0.004). This could be due to genomic DNA instability and alternation in chromatins accessibility resulted from abnormal L1Hs hypomethylation, as showed in this study with HCT-15 cells treated with methylation inhibitor 5-Aza.

RNA-Sequencing Analyses Demonstrate the Involvement of Canonical Transient Receptor Potential Channels in Rat Tooth Germ Development

PubMed Central

Yang, Jun; Cai, Wenping; Lu, Xi; Liu, Shangfeng; Zhao, Shouliang

2017-01-01

Tooth development depends on multiple molecular interactions between the dental epithelium and mesenchyme, which are derived from ectodermal and ectomesenchymal cells, respectively. We report on a systematic RNA sequencing analysis of transcriptional expression levels from the bud to hard tissue formation stages of rat tooth germ development. We found that GNAO1, ENO1, EFNB1, CALM1, SIAH2, ATP6V0A1, KDELR2, GTPBP1, POLR2C, SORT1, and members of the canonical transient receptor potential (TRPC) channel family are involved in tooth germ development. Furthermore, Cell Counting Kit 8 (CCK8) and Transwell migration assays were performed to explore the effects of these differentially expressed genes (DEGs) on the proliferation and migration of dental pulp stem cells. Immunostaining revealed that TRPC channels are expressed at varying levels during odontogenesis. The identified genes represent novel candidates that are likely to be vital for rat tooth germ development. Together, the results provide a valuable resource to elucidate the gene regulatory mechanisms underlying mammalian tooth germ development. PMID:28706494

Interaction between DMRT1 function and genetic background modulates signaling and pluripotency to control tumor susceptibility in the fetal germ line

PubMed Central

Krentz, Anthony D.; Murphy, Mark W.; Zhang, Teng; Sarver, Aaron L.; Jain, Sanjay; Griswold, Michael D.; Bardwell, Vivian J.; Zarkower, David

2013-01-01

Dmrt1(doublesex and mab-3 related transcription factor 1) is a regulator of testis development in vertebrates that has been implicated in testicular germ cell tumors of mouse and human. In the fetal mouse testis Dmrt1 regulates germ cell pluripotency in a strain-dependent manner. Loss of Dmrt1 in 129Sv strain mice results in a >90% incidence of testicular teratomas, tumors consisting cells of multiple germ layers; by contrast, these tumors have never been observed in Dmrt1 mutants of C57BL/6J (B6) or mixed genetic backgrounds. To further investigate the interaction between Dmrt1 and genetic background we compared mRNA expression in wild type and Dmrt1 mutant fetal testes of 129Sv and B6 mice at embryonic day 15.5 (E15.5), prior to overt tumorigenesis. Loss of Dmrt1 caused misexpression of overlapping but distinct sets of mRNAs in the two strains. The mRNAs that were selectively affected included some that changed expression only in one strain or the other and some that changed in both strains but to a greater degree in one versus the other. In particular, loss of Dmrt1 in 129Sv testes caused a more severe failure to silence regulators of pluripotency than in B6 testes. A number of genes misregulated in 129Sv mutant testes also are misregulated in human testicular germ cell tumors (TGCTs), suggesting similar etiology between germ cell tumors in mouse and man. Expression profiling showed that DMRT1 also regulates pluripotency genes in the fetal ovary, although Dmrt1 mutant females do not develop teratomas. Pathway analysis indicated disruption of several signaling pathways in Dmrt1 mutant fetal testes, including Nodal, Notch, and GDNF. We used a Nanos3-cre knock-in allele to perform conditional gene targeting, testing the GDNF coreceptors Gfra1 and Ret for effects on teratoma susceptibility. Conditional deletion of Gfra1 but not Ret in fetal germ cells of animals outcrossed to 129Sv caused a modest but significant elevation in tumor incidence. Despite some variability in genetic background in these crosses, this result is consistent with previous genetic mapping of teratoma susceptibility loci to the region containing Gfra1. Using Nanos3-cre we also uncovered a strong genetic interaction between Dmrt1 and Nanos3, suggesting parallel functions for these two genes in fetal germ cells. Finally, we used chromatin immunoprecipitation (ChIP-seq) analysis to identify a number of potentially direct DMRT1 targets. This analysis suggested that DMRT1 controls pluripotency via transcriptional repression of Esrrb, Nr5a2/Lrh1, and Sox2. Given the strong evidence for involvement of DMRT1 in human TGCT, the downstream genes and pathways identified in this study provide potentially useful candidates for roles in the human disease. PMID:23473982

EMMPRIN (basigin/CD147) is involved in the morphogenesis of tooth germ in mouse molars.

PubMed

Xie, Ming; Jiao, Ting; Chen, Yuqin; Xu, Chun; Li, Jing; Jiang, Xinquan; Zhang, Fuqiang

2010-05-01

The pattern of gene expression for extracellular matrix metalloproteinase inducer (EMMPRIN) was revealed in the tooth germ of mouse mandibular molars using quantitative real-time PCR. In situ hybridization and immunohistochemical study demonstrated the characteristic distribution of EMMPRIN in the different stages of tooth germ development. To investigate the functional role played by EMMPRIN in tooth germ development, EMMPRIN siRNA interference approach was carried out in cultured mouse mandibles at embryonic day 11.0 (E11.0). The results showed that EMMPRIN siRNA-treated explants exhibited a marked growth inhibition of tooth germ compared to the control and scrambled siRNA-treated explants. Meanwhile, a significant increase in MT1-MMP mRNA expression and a reduction in MMP-2, MMP-3, MMP-9, MMP-13 and MT2-MMP mRNA expression were observed in the mouse mandibles following EMMPRIN abrogation. The current results indicate that EMMPRIN could thus be involved in the early stage of tooth germ development and morphogenesis, possibly by regulating the expression of MMP genes.

Risk factors in past histories and familial episodes related to development of testicular germ cell tumor.

PubMed

Kanto, Satoru; Hiramatsu, Masayoshi; Suzuki, Kenichi; Ishidoya, Shigeto; Saito, Hideo; Yamada, Shigeyuki; Satoh, Makoto; Saito, Seiichi; Fukuzaki, Atsushi; Arai, Yoichi

2004-08-01

A retrospective study was conducted to examine the host factors of 240 testicular germ cell tumor patients. This study was performed to address a new theory proposed by Skakkebaek called testicular dysgenesis syndrome which claims that cryptorchism, hypospadias, poor semen quality and testicular germ cell tumors are symptoms of an underlying testicular dysgenesis in uterus. The past health histories and familial episodes of 240 testicular germ cell tumor patients were examined. The past health histories included cryptorchism, hypospadias, infertility, atrophic testis and inguinal hernia. Of the 240 patients, 13 (5.4%) had a history of cryptorchism or orchidopexy. Two (0.8%) showed existence of hypospadias or had experienced urethroplasty. Among 129 married couples, 104 (80.6%) couples were fertile. Three (1.3%) patients developed testicular tumors after they were diagnosed as infertile or came to the hospital with the complaints of infertility. Four (1.7%) had contralateral atrophic testis. 19 (7.9%) had experienced inguinal herniorrhaphy before age 15. Three (1.3%) had testicular germ cell tumor patients among their family or relatives. The testicular germ cell tumor patients showed a considerable incidence of complications such as cryptorchism, hypospadias and incomplete closure of processus vaginalis. Cryptorchism, perinatal factors and familial factors could be risks for developing testicular germ cell tumors.

[Acute myeloid leukemia possibly originating from the same clone of testicular germ cell tumor].

PubMed

Suyama, Takuya; Obara, Naoshi; Kawai, Koji; Yamada, Kenji; Kusakabe, Manabu; Kurita, Naoki; Nishikii, Hidekazu; Yokoyama, Yasuhisa; Suzukawa, Kazumi; Hasegawa, Yuichi; Noguchi, Masayuki; Chiba, Shigeru

2013-08-01

This report describes a 30-year-old man with a testicular germ cell tumor, which later developed into acute myeloid leukemia (AML) with a common chromosomal abnormality. Testicular germ cell tumors had developed at the age of 26. He was successfully treated with surgery followed by chemotherapy.Four years after the onset of the germ cell tumor, he developed pancytopenia with elevated serum LDH. More than 95% of the bone marrow was occupied by blastic cells. These cells were CD13+, CD34+ but CD45- and MPO-. Amplification of the short arm of chromosome 12 was recognized by fluorescence in situ hybridization using the blastic cells in the bone marrow and the previous testicular tumor specimen. Because testicular germ cell tumor recurrence and other malignant tumors could be ruled out pathologically, he was diagnosed as having AML.Allogeneic stem cell transplantation from a HLA-matched sibling donor was performed after chemotherapy. As of 19 months after the transplantation, recurrence of neither AML nor testicular tumors has been observed. Because the same genetic abnormality was observed in the testicular germ cell tumor and AML in this case, the possibility of AML having a common origin with the testicular germ cell tumor is indicated.

An in vivo proteomic analysis of the Me31B interactome in Drosophila germ granules.

PubMed

DeHaan, Hunter; McCambridge, Aidan; Armstrong, Brittany; Cruse, Carlie; Solanki, Dhruv; Trinidad, Jonathan C; Arkov, Alexey L; Gao, Ming

2017-11-01

Drosophila Me31B is a conserved protein of germ granules, ribonucleoprotein complexes essential for germ cell development. Me31B post-transcriptionally regulates mRNAs by interacting with other germ granule proteins. However, a Me31B interactome is lacking. Here, we use an in vivo proteomics approach to show that the Me31B interactome contains polypeptides from four functional groups: RNA regulatory proteins, glycolytic enzymes, cytoskeleton/motor proteins, and germ plasm components. We further show that Me31B likely colocalizes with the germ plasm components Tudor (Tud), Vasa, and Aubergine in the nuage and germ plasm and provide evidence that Me31B may directly bind to Tud in a symmetrically dimethylated arginine-dependent manner. Our study supports the role of Me31B in RNA regulation and suggests its novel roles in germ granule assembly and function. © 2017 Federation of European Biochemical Societies.

Micro-RNA expression in cisplatin resistant germ cell tumor cell lines

PubMed Central

2011-01-01

Background We compared microRNA expression patterns in three cisplatin resistant sublines derived from paternal cisplatin sensitive germ cell tumor cell lines in order to improve our understanding of the mechanisms of cisplatin resistance. Methods Three cisplatin resistant sublines (NTERA-2-R, NCCIT-R, 2102EP-R) showing 2.7-11.3-fold increase in drug resistance after intermittent exposure to increasing doses of cisplatin were compared to their parental counterparts, three well established relatively cisplatin sensitive germ cell tumor cell lines (NTERA-2, NCCIT, 2102EP). Cells were cultured and total RNA was isolated from all 6 cell lines in three independent experiments. RNA was converted into cDNA and quantitative RT-PCR was run using 384 well low density arrays covering almost all (738) known microRNA species of human origin. Results Altogether 72 of 738 (9.8%) microRNAs appeared differentially expressed between sensitive and resistant cell line pairs (NTERA-2R/NTERA-2 = 43, NCCIT-R/NCCIT = 53, 2102EP-R/2102EP = 15) of which 46.7-95.3% were up-regulated (NTERA-2R/NTERA-2 = 95.3%, NCCIT-R/NCCIT = 62.3%, 2102EP-R/2102EP = 46.7%). The number of genes showing differential expression in more than one of the cell line pairs was 34 between NTERA-2R/NTERA-2 (79%) and NCCIT-R/NCCIT (64%), and 3 and 4, respectively, between these two cell lines and 2102EP-R/2102EP (about 27%). Only the has-miR-10b involved in breast cancer invasion and metastasis and has-miR-512-3p appeared to be up-regulated (2-3-fold) in all three cell lines. The hsa-miR-371-373 cluster (counteracting cellular senescence and linked with differentiation potency), as well as hsa-miR-520c/-520h (inhibiting the tumor suppressor p21) were 3.9-16.3 fold up-regulated in two of the three cisplatin resistant cell lines. Several new micro-RNA species missing an annotation towards cisplatin resistance could be identified. These were hsa-miR-512-3p/-515/-517/-518/-525 (up to 8.1-fold up-regulated) and hsa-miR-99a/-100/-145 (up to 10-fold down-regulated). Conclusion Examining almost all known human micro-RNA species confirmed the miR-371-373 cluster as a promising target for explaining cisplatin resistance, potentially by counteracting wild-type P53 induced senescence or linking it with the potency to differentiate. Moreover, we describe for the first time an association of the up-regulation of micro-RNA species such as hsa-miR-512-3p/-515/-517/-518/-525 and down-regulation of hsa-miR-99a/-100/-145 with a cisplatin resistant phenotype in human germ cell tumors. Further functional analyses are warranted to gain insight into their role in drug resistance. PMID:21575166

Molecular biological features of male germ cell differentiation

PubMed Central

HIROSE, MIKA; TOKUHIRO, KEIZO; TAINAKA, HITOSHI; MIYAGAWA, YASUSHI; TSUJIMURA, AKIRA; OKUYAMA, AKIHIKO; NISHIMUNE, YOSHITAKE

2007-01-01

Somatic cell differentiation is required throughout the life of a multicellular organism to maintain homeostasis. In contrast, germ cells have only one specific function; to preserve the species by conveying the parental genes to the next generation. Recent studies of the development and molecular biology of the male germ cell have identified many genes, or isoforms, that are specifically expressed in the male germ cell. In the present review, we consider the unique features of male germ cell differentiation. (Reprod Med Biol 2007; 6: 1–9) PMID:29699260

A Mechanism of Male Germ Cell Apoptosis Induced by Bisphenol-A and Nonylphenol Involving ADAM17 and p38 MAPK Activation

PubMed Central

Moreno, Ricardo D.

2014-01-01

Germ cell apoptosis regulation is pivotal in order to maintain proper daily sperm production. Several reports have shown that endocrine disruptors such as Bisphenol-A (BPA) and Nonylphenol (NP) induce germ cell apoptosis along with a decrease in sperm production. Given their ubiquitous distribution in plastic products used by humans it is important to clarify their mechanism of action. TACE/ADAM17 is a widely distributed extracellular metalloprotease and participates in the physiological apoptosis of germ cells during spermatogenesis. The aims of this work were: 1) to determine whether BPA and NP induce ADAM17 activation; and 2) to study whether ADAM17 and/or ADAM10 are involved in germ cell apoptosis induced by BPA and NP in the pubertal rat testis. A single dose of BPA or NP (50 mg/kg) induces germ cell apoptosis in 21-day-old male rats, which was prevented by a pharmacological inhibitor of ADAM17, but not by an inhibitor of ADAM10. In vitro, we showed that BPA and NP, at similar concentrations to those found in human samples, induce the shedding of exogenous and endogenous (TNF-α) ADAM17 substrates in primary rat Sertoli cell cultures and TM4 cell line. In addition, pharmacological inhibitors of metalloproteases and genetic silencing of ADAM17 prevent the shedding induced in vitro by BPA and NP. Finally, we showed that in vivo BPA and NP induced early activation (phosphorylation) of p38 MAPK and translocation of ADAM17 to the cell surface. Interestingly, the inhibition of p38 MAPK prevents germ cell apoptosis and translocation of ADAM17 to the cell surface. These results show for the first time that xenoestrogens can induce activation of ADAM17 at concentrations similar to those found in human samples, suggesting a mechanism by which they could imbalance para/juxtacrine cell-to-cell-communication and induce germ cell apoptosis. PMID:25474107

Stochastic Seeding Coupled with mRNA Self-Recruitment Generates Heterogeneous Drosophila Germ Granules.

PubMed

Niepielko, Matthew G; Eagle, Whitby V I; Gavis, Elizabeth R

2018-06-18

The formation of ribonucleoprotein assemblies called germ granules is a conserved feature of germline development. In Drosophila, germ granules form at the posterior of the oocyte in a specialized cytoplasm called the germ plasm, which specifies germline fate during embryogenesis. mRNAs, including nanos (nos) and polar granule component (pgc), that function in germline development are localized to the germ plasm through their incorporation into germ granules, which deliver them to the primordial germ cells. Germ granules are nucleated by Oskar (Osk) protein and contain varying combinations and quantities of their constituent mRNAs, which are organized as spatially distinct, multi-copy homotypic clusters. The process that gives rise to such heterogeneous yet organized granules remains unknown. Here, we show that individual nos and pgc transcripts can populate the same nascent granule, and these first transcripts then act as seeds, recruiting additional like transcripts to form homotypic clusters. Within a granule, homotypic clusters grow independently of each other but depend on the simultaneous acquisition of additional Osk. Although granules can contain multiple clusters of a particular mRNA, granule mRNA content is dominated by cluster size. These results suggest that the accumulation of mRNAs in the germ plasm is controlled by the mRNAs themselves through their ability to form homotypic clusters; thus, RNA self-association drives germ granule mRNA localization. We propose that a stochastic seeding and self-recruitment mechanism enables granules to simultaneously incorporate many different mRNAs while ensuring that each becomes enriched to a functional threshold. Copyright © 2018 Elsevier Ltd. All rights reserved.

ENU Mutagenesis in Mice Identifies Candidate Genes For Hypogonadism

PubMed Central

Weiss, Jeffrey; Hurley, Lisa A.; Harris, Rebecca M.; Finlayson, Courtney; Tong, Minghan; Fisher, Lisa A.; Moran, Jennifer L.; Beier, David R.; Mason, Christopher; Jameson, J. Larry

2012-01-01

Genome-wide mutagenesis was performed in mice to identify candidate genes for male infertility, for which the predominant causes remain idiopathic. Mice were mutagenized using N-ethyl-N-nitrosourea (ENU), bred, and screened for phenotypes associated with the male urogenital system. Fifteen heritable lines were isolated and chromosomal loci were assigned using low density genome-wide SNP arrays. Ten of the fifteen lines were pursued further using higher resolution SNP analysis to narrow the candidate gene regions. Exon sequencing of candidate genes identified mutations in mice with cystic kidneys (Bicc1), cryptorchidism (Rxfp2), restricted germ cell deficiency (Plk4), and severe germ cell deficiency (Prdm9). In two other lines with severe hypogonadism candidate sequencing failed to identify mutations, suggesting defects in genes with previously undocumented roles in gonadal function. These genomic intervals were sequenced in their entirety and a candidate mutation was identified in SnrpE in one of the two lines. The line harboring the SnrpE variant retains substantial spermatogenesis despite small testis size, an unusual phenotype. In addition to the reproductive defects, heritable phenotypes were observed in mice with ataxia (Myo5a), tremors (Pmp22), growth retardation (unknown gene), and hydrocephalus (unknown gene). These results demonstrate that the ENU screen is an effective tool for identifying potential causes of male infertility. PMID:22258617

Paclitaxel, Ifosfamide, and Cisplatin Efficacy for First-Line Treatment of Patients With Intermediate- or Poor-Risk Germ Cell Tumors

PubMed Central

Hu, James; Dorff, Tanya B.; Lim, Kristina; Patil, Sujata; Woo, Kaitlin M.; Carousso, Maryann; Hughes, Amanda; Sheinfeld, Joel; Bains, Manjit; Daneshmand, Siamak; Ketchens, Charlene; Bajorin, Dean F.; Bosl, George J.; Quinn, David I.; Motzer, Robert J.

2016-01-01

Purpose Paclitaxel, ifosfamide, and cisplatin (TIP) achieved complete responses (CRs) in two thirds of patients with advanced germ cell tumors (GCTs) who relapsed after first-line chemotherapy with cisplatin and etoposide with or without bleomycin. We tested the efficacy of first-line TIP in patients with intermediate- or poor-risk disease. Patients and Methods In this prospective, multicenter, single-arm phase II trial, previously untreated patients with International Germ Cell Cancer Collaborative Group poor-risk or modified intermediate-risk GCTs received four cycles of TIP (paclitaxel 240 mg/m2 over 2 days, ifosfamide 6 g/m2 over 5 days with mesna support, and cisplatin 100 mg/m2 over 5 days) once every 3 weeks with granulocyte colony-stimulating factor support. The primary end point was the CR rate. Results Of the first 41 evaluable patients, 28 (68%) achieved a CR, meeting the primary efficacy end point. After additional accrual on an extension phase, total enrollment was 60 patients, including 40 (67%) with poor risk and 20 (33%) with intermediate risk. Thirty-eight (68%) of 56 evaluable patients achieved a CR and seven (13%) achieved partial responses with negative markers (PR-negative) for a favorable response rate of 80%. Five of seven achieving PR-negative status had seminoma and therefore did not undergo postchemotherapy resection of residual masses. Estimated 3-year progression-free survival and overall survival rates were 72% (poor risk, 63%; intermediate risk, 90%) and 91% (poor risk, 87%; intermediate risk, 100%), respectively. Grade 3 to 4 toxicities consisted primarily of reversible hematologic or electrolyte abnormalities, including neutropenic fever in 18%. Conclusion TIP demonstrated efficacy as first-line therapy for intermediate- and poor-risk GCTs with an acceptable safety profile. Given higher rates of favorable response, progression-free survival, and overall survival compared with prior first-line studies, TIP warrants further study in this population. PMID:27185842

A paternal environmental legacy: evidence for epigenetic inheritance through the male germ line.

PubMed

Soubry, Adelheid; Hoyo, Cathrine; Jirtle, Randy L; Murphy, Susan K

2014-04-01

Literature on maternal exposures and the risk of epigenetic changes or diseases in the offspring is growing. Paternal contributions are often not considered. However, some animal and epidemiologic studies on various contaminants, nutrition, and lifestyle-related conditions suggest a paternal influence on the offspring's future health. The phenotypic outcomes may have been attributed to DNA damage or mutations, but increasing evidence shows that the inheritance of environmentally induced functional changes of the genome, and related disorders, are (also) driven by epigenetic components. In this essay we suggest the existence of epigenetic windows of susceptibility to environmental insults during sperm development. Changes in DNA methylation, histone modification, and non-coding RNAs are viable mechanistic candidates for a non-genetic transfer of paternal environmental information, from maturing germ cell to zygote. Inclusion of paternal factors in future research will ultimately improve the understanding of transgenerational epigenetic plasticity and health-related effects in future generations. © 2014 The Authors. Bioessays published by WILEY Periodicals, Inc.

Identification of tissues and patterning events required for distinct steps in early migration of zebrafish primordial germ cells.

PubMed

Weidinger, G; Wolke, U; Köprunner, M; Klinger, M; Raz, E

1999-12-01

In many organisms, the primordial germ cells have to migrate from the position where they are specified towards the developing gonad where they generate gametes. Extensive studies of the migration of primordial germ cells in Drosophila, mouse, chick and Xenopus have identified somatic tissues important for this process and demonstrated a role for specific molecules in directing the cells towards their target. In zebrafish, a unique situation is found in that the primordial germ cells, as marked by expression of vasa mRNA, are specified in random positions relative to the future embryonic axis. Hence, the migrating cells have to navigate towards their destination from various starting positions that differ among individual embryos. Here, we present a detailed description of the migration of the primordial germ cells during the first 24 hours of wild-type zebrafish embryonic development. We define six distinct steps of migration bringing the primordial germ cells from their random positions before gastrulation to form two cell clusters on either side of the midline by the end of the first day of development. To obtain information on the origin of the positional cues provided to the germ cells by somatic tissues during their migration, we analyzed the migration pattern in mutants, including spadetail, swirl, chordino, floating head, cloche, knypek and no isthmus. In mutants with defects in axial structures, paraxial mesoderm or dorsoventral patterning, we find that certain steps of the migration process are specifically affected. We show that the paraxial mesoderm is important for providing proper anteroposterior information to the migrating primordial germ cells and that these cells can respond to changes in the global dorsoventral coordinates. In certain mutants, we observe accumulation of ectopic cells in different regions of the embryo. These ectopic cells can retain both morphological and molecular characteristics of primordial germ cells, suggesting that, in zebrafish at the early stages tested, the vasa-expressing cells are committed to the germ cell lineage.

Germ line variants predispose to both JAK2 V617F clonal hematopoiesis and myeloproliferative neoplasms

PubMed Central

Hinds, David A.; Barnholt, Kimberly E.; Mesa, Ruben A.; Kiefer, Amy K.; Do, Chuong B.; Eriksson, Nicholas; Mountain, Joanna L.; Francke, Uta; Tung, Joyce Y.; Nguyen, Huong (Marie); Zhang, Haiyu; Gojenola, Linda; Zehnder, James L.

2016-01-01

We conducted a genome-wide association study (GWAS) to identify novel predisposition alleles associated with Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs) and JAK2 V617F clonal hematopoiesis in the general population. We recruited a web-based cohort of 726 individuals with polycythemia vera, essential thrombocythemia, and myelofibrosis and 252 637 population controls unselected for hematologic phenotypes. Using a single-nucleotide polymorphism (SNP) array platform with custom probes for the JAK2 V617F mutation (V617F), we identified 497 individuals (0.2%) among the population controls who were V617F carriers. We performed a combined GWAS of the MPN cases plus V617F carriers in the control population (n = 1223) vs the remaining controls who were noncarriers for V617F (n = 252 140). For these MPN cases plus V617F carriers, we replicated the germ line JAK2 46/1 haplotype (rs59384377: odds ratio [OR] = 2.4, P = 6.6 × 10−89), previously associated with V617F-positive MPN. We also identified genome-wide significant associations in the TERT gene (rs7705526: OR = 1.8, P = 1.1 × 10−32), in SH2B3 (rs7310615: OR = 1.4, P = 3.1 × 10−14), and upstream of TET2 (rs1548483: OR = 2.0, P = 2.0 × 10−9). These associations were confirmed in a separate replication cohort of 446 V617F carriers vs 169 021 noncarriers. In a joint analysis of the combined GWAS and replication results, we identified additional genome-wide significant predisposition alleles associated with CHEK2, ATM, PINT, and GFI1B. All SNP ORs were similar for MPN patients and controls who were V617F carriers. These data indicate that the same germ line variants endow individuals with a predisposition not only to MPN, but also to JAK2 V617F clonal hematopoiesis, a more common phenomenon that may foreshadow the development of an overt neoplasm. PMID:27365426

Optimized gene editing technology for Drosophila melanogaster using germ line-specific Cas9.

PubMed

Ren, Xingjie; Sun, Jin; Housden, Benjamin E; Hu, Yanhui; Roesel, Charles; Lin, Shuailiang; Liu, Lu-Ping; Yang, Zhihao; Mao, Decai; Sun, Lingzhu; Wu, Qujie; Ji, Jun-Yuan; Xi, Jianzhong; Mohr, Stephanie E; Xu, Jiang; Perrimon, Norbert; Ni, Jian-Quan

2013-11-19

The ability to engineer genomes in a specific, systematic, and cost-effective way is critical for functional genomic studies. Recent advances using the CRISPR-associated single-guide RNA system (Cas9/sgRNA) illustrate the potential of this simple system for genome engineering in a number of organisms. Here we report an effective and inexpensive method for genome DNA editing in Drosophila melanogaster whereby plasmid DNAs encoding short sgRNAs under the control of the U6b promoter are injected into transgenic flies in which Cas9 is specifically expressed in the germ line via the nanos promoter. We evaluate the off-targets associated with the method and establish a Web-based resource, along with a searchable, genome-wide database of predicted sgRNAs appropriate for genome engineering in flies. Finally, we discuss the advantages of our method in comparison with other recently published approaches.

Designer babies on tap? Medical students' attitudes to pre-implantation genetic screening.

PubMed

Meisenberg, Gerhard

2009-03-01

This paper describes two studies about the determinants of attitudes to pre-implantation genetic screening in a multicultural sample of medical students from the United States. Sample sizes were 292 in study 1 and 1464 in study 2. Attitudes were of an undifferentiated nature, but respondents did make a major distinction between use for disease prevention and use for enhancement. No strong distinctions were made between embryo selection and germ line gene manipulations, and between somatic gene therapy and germ line gene manipulations. Religiosity was negatively associated with acceptance of "designer baby" technology for Christians and Muslims but not Hindus. However, the strongest and most consistent influence was an apparently moralistic stance against active and aggressive interference with natural processes in general. Trust in individuals and institutions was unrelated to acceptance of the technology, indicating that fear of abuse by irresponsible individuals and corporations is not an important determinant of opposition.

[Chromatin in diapause of the silkworm Bombyx mori L.: thermal parthenogenesis and normal development].

PubMed

Klimenko, V V; Khaoiuan', Lian

2012-01-01

Having used hematoxylin as a stain, some features of silkworm embryo chromatin in diapause have been studied in normal and parthenogenetic development. With found direct correlation between the number of interphase chromatin grains and the number of chromosomes in the nucleus, we examined cell polyploidization in the embryo at diapause stage. Polyploidization by parthenogenesis is not reducible to endomitotic doubling of the chromosome set because it comprises 6n-nuclei. Explanation of more diverse range of polyploid cells in parthenogenesis needs to consider the fusion of cleavage nuclei that is carried out by the cytoplasmic karyogamic mechanism in the absence of fertilization. For the first time on squash preparations, in diapausing embryo, we have identified primary germ cells (PGC) that are characterized by less compact chromatin, especially in the zygotic form of development, a larger size of the nucleus and cytoplasm, and irregular number and size of nucleoli. Evaluation of PGC ploidy in parthenogenesis by calculation of "loose" chromatin grains in diapause is possible and testifies polyploidization in embryo germ-line. This explains the inevitable admixture of tetraploid eggs in diploid parthenoclone grain and its absence in normal development. Cytological method used has revealed a spiral arrangement of chromatin grains on the inner surface of the nucleus at different levels of ploidy.

Quantitative Differences in a Single Maternal Factor Determine Survival Probabilities among Drosophila Germ Cells.

PubMed

Slaidina, Maija; Lehmann, Ruth

2017-01-23

Germ cell death occurs in many species [1-3] and has been proposed as a mechanism by which the fittest, strongest, or least damaged germ cells are selected for transmission to the next generation. However, little is known about how the choice is made between germ cell survival and death. Here, we focus on the mechanisms that regulate germ cell survival during embryonic development in Drosophila. We find that the decision to die is a germ cell-intrinsic process linked to quantitative differences in germ plasm inheritance, such that higher germ plasm inheritance correlates with higher primordial germ cell (PGC) survival probability. We demonstrate that the maternal factor lipid phosphate phosphatase Wunen-2 (Wun2) regulates PGC survival in a dose-dependent manner. Since wun2 mRNA levels correlate with the levels of other maternal determinants at the single-cell level, we propose that Wun2 is used as a readout of the overall germ plasm quantity, such that only PGCs with the highest germ plasm quantity survive. Furthermore, we demonstrate that Wun2 and p53, another regulator of PGC survival, have opposite yet independent effects on PGC survival. Since p53 regulates cell death upon DNA damage and various cellular stresses, we hypothesize that together they ensure selection of the PGCs with highest germ plasm quantity and least cellular damage. Copyright © 2017 Elsevier Ltd. All rights reserved.

Anchoring Junctions As Drug Targets: Role in Contraceptive Development

PubMed Central

Mruk, Dolores D.; Silvestrini, Bruno; Cheng, C. Yan

2010-01-01

In multicellular organisms, cell-cell interactions are mediated in part by cell junctions, which underlie tissue architecture. Throughout spermatogenesis, for instance, preleptotene leptotene spermatocytes residing in the basal compartment of the seminiferous epithelium must traverse the blood-testis barrier to enter the adluminal compartment for continued development. At the same time, germ cells must also remain attached to Sertoli cells, and numerous studies have reported extensive restructuring at the Sertoli-Sertoli and Sertoli-germ cell interface during germ cell movement across the seminiferous epithelium. Furthermore, the proteins and signaling cascades that regulate adhesion between testicular cells have been largely delineated. These findings have unveiled a number of potential “druggable” targets that can be used to induce premature release of germ cells from the seminiferous epithelium, resulting in transient infertility. Herein, we discuss a novel approach with the aim of developing a nonhormonal male contraceptive for future human use, one that involves perturbing adhesion between Sertoli and germ cells in the testis. PMID:18483144

Maternal dazap2 Regulates Germ Granules by Counteracting Dynein in Zebrafish Primordial Germ Cells.

PubMed

Forbes, Meredyth M; Rothhämel, Sophie; Jenny, Andreas; Marlow, Florence L

2015-07-07

Primordial germ cells (PGCs) are the stem cells of the germline. Generally, germline induction occurs via zygotic factors or the inheritance of maternal determinants called germ plasm (GP). GP is packaged into ribonucleoprotein complexes within oocytes and later promotes the germline fate in embryos. Once PGCs are specified by either mechanism, GP components localize to perinuclear granular-like structures. Although components of zebrafish PGC germ granules have been studied, the maternal factors regulating their assembly and contribution to germ cell development are unknown. Here, we show that the scaffold protein Dazap2 binds to Bucky ball, an essential regulator of oocyte polarity and GP assembly, and colocalizes with the GP in oocytes and in PGCs. Mutational analysis revealed a requirement for maternal Dazap2 (MDazap2) in germ-granule maintenance. Through molecular epistasis analyses, we show that MDazap2 is epistatic to Tdrd7 and maintains germ granules in the embryonic germline by counteracting Dynein activity. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Germ cells are not the primary factor for sexual fate determination in goldfish.

PubMed

Goto, Rie; Saito, Taiju; Takeda, Takahiro; Fujimoto, Takafumi; Takagi, Misae; Arai, Katsutoshi; Yamaha, Etsuto

2012-10-01

The presence of germ cells in the early gonad is important for sexual fate determination and gonadal development in vertebrates. Recent studies in zebrafish and medaka have shown that a lack of germ cells in the early gonad induces sex reversal in favor of a male phenotype. However, it is uncertain whether the gonadal somatic cells or the germ cells are predominant in determining gonadal fate in other vertebrate. Here, we investigated the role of germ cells in gonadal differentiation in goldfish, a gonochoristic species that possesses an XX-XY genetic sex determination system. The primordial germ cells (PGCs) of the fish were eliminated during embryogenesis by injection of a morpholino oligonucleotide against the dead end gene. Fish without germ cells showed two types of gonadal morphology: one with an ovarian cavity; the other with seminiferous tubules. Next, we tested whether function could be restored to these empty gonads by transplantation of a single PGC into each embryo, and also determined the gonadal sex of the resulting germline chimeras. Transplantation of a single GFP-labeled PGC successfully produced a germline chimera in 42.7% of the embryos. Some of the adult germline chimeras had a developed gonad on one side that contained donor derived germ cells, while the contralateral gonad lacked any early germ cell stages. Female germline chimeras possessed a normal ovary and a germ-cell free ovary-like structure on the contralateral side; this structure was similar to those seen in female morphants. Male germline chimeras possessed a testis and a contralateral empty testis that contained some sperm in the tubular lumens. Analysis of aromatase, foxl2 and amh expression in gonads of morphants and germline chimeras suggested that somatic transdifferentiation did not occur. The offspring of fertile germline chimeras all had the donor-derived phenotype, indicating that germline replacement had occurred and that the transplanted PGC had rescued both female and male gonadal function. These findings suggest that the absence of germ cells did not affect the pathway for ovary or testis development and that phenotypic sex in goldfish is determined by somatic cells under genetic sex control rather than an interaction between the germ cells and somatic cells. Copyright © 2012 Elsevier Inc. All rights reserved.

Whole-genome sequencing analysis of phenotypic heterogeneity and anticipation in Li-Fraumeni cancer predisposition syndrome.

PubMed

Ariffin, Hany; Hainaut, Pierre; Puzio-Kuter, Anna; Choong, Soo Sin; Chan, Adelyne Sue Li; Tolkunov, Denis; Rajagopal, Gunaretnam; Kang, Wenfeng; Lim, Leon Li Wen; Krishnan, Shekhar; Chen, Kok-Siong; Achatz, Maria Isabel; Karsa, Mawar; Shamsani, Jannah; Levine, Arnold J; Chan, Chang S

2014-10-28

The Li-Fraumeni syndrome (LFS) and its variant form (LFL) is a familial predisposition to multiple forms of childhood, adolescent, and adult cancers associated with germ-line mutation in the TP53 tumor suppressor gene. Individual disparities in tumor patterns are compounded by acceleration of cancer onset with successive generations. It has been suggested that this apparent anticipation pattern may result from germ-line genomic instability in TP53 mutation carriers, causing increased DNA copy-number variations (CNVs) with successive generations. To address the genetic basis of phenotypic disparities of LFS/LFL, we performed whole-genome sequencing (WGS) of 13 subjects from two generations of an LFS kindred. Neither de novo CNV nor significant difference in total CNV was detected in relation with successive generations or with age at cancer onset. These observations were consistent with an experimental mouse model system showing that trp53 deficiency in the germ line of father or mother did not increase CNV occurrence in the offspring. On the other hand, individual records on 1,771 TP53 mutation carriers from 294 pedigrees were compiled to assess genetic anticipation patterns (International Agency for Research on Cancer TP53 database). No strictly defined anticipation pattern was observed. Rather, in multigeneration families, cancer onset was delayed in older compared with recent generations. These observations support an alternative model for apparent anticipation in which rare variants from noncarrier parents may attenuate constitutive resistance to tumorigenesis in the offspring of TP53 mutation carriers with late cancer onset.

Cryopreservation of green fluorescent protein (GFP)-labeled primordial germ cells with GFP fused to the 3' untranslated region of the nanos gene by vitrification of Japanese eel (Anguilla japonica) somite stage embryos.

PubMed

Kawakami, Y; Ishihara, M; Saito, T; Fujimoto, T; Adachi, S; Arai, K; Yamaha, E

2012-12-01

Primordial germ cells (PGC) are the only cell type in developing embryos with the potential to transmit genetic information to the next generation. In this study, PGC of Japanese eel (Anguilla japonica) were visualized by injection of mRNA synthesized from a construct carrying the green fluorescent protein (GFP) gene fused to the 3' untranslated region of the Japanese eel nanos gene. We investigated the feasibility of cryopreserving Japanese eel PGC by vitrification of dechorionated whole somite stage embryos. The GFP-labeled PGC were rapidly cooled using liquid nitrogen after exposure to a pretreatment solution containing 1.5 M cryoprotectant (methanol, dimethyl sulfoxide, and glycerol for 10 min and ethylene glycol for 10, 20, and 30 min) and a vitrification solution containing 3 M cryoprotectant and 0.5 M sucrose for 1, 5, and 10 min. Ethylene glycerol is an effective cryoprotectant for embryonic cells and shows no evidence of ice formation after thawing. Vitrified and thawed PGC were transplanted into blastula stage embryos from zebrafish (Danio rerio). The GFP-labeled PGC migrated toward the host gonadal ridge, suggesting maintenance of their normal migration motility. These techniques may assist in achieving inter- and intraspecies germ-line chimers using donor Japanese eel PGC.

DAZL is essential for stress granule formation implicated in germ cell survival upon heat stress.

PubMed

Kim, Byunghyuk; Cooke, Howard J; Rhee, Kunsoo

2012-02-01

Mammalian male germ cells should be maintained below body temperature for proper development. Here, we investigated how male germ cells respond to heat stress. A short exposure of mouse testes to core body temperature induced phosphorylation of eIF2α and the formation of stress granules (SGs) in male germ cells. We observed that DAZL, a germ cell-specific translational regulator, was translocated to SGs upon heat stress. Furthermore, SG assembly activity was significantly diminished in the early male germ cells of Dazl-knockout mice. The DAZL-containing SGs played a protective role against heat stress-induced apoptosis by the sequestration of specific signaling molecules, such as RACK1, and the subsequent blockage of the apoptotic MAPK pathway. Based on these results, we propose that DAZL is an essential component of the SGs, which prevent male germ cells from undergoing apoptosis upon heat stress.

Biolistics Transformation of Wheat

NASA Astrophysics Data System (ADS)

Sparks, Caroline A.; Jones, Huw D.

We present a complete, step-by-step guide to the production of transformed wheat plants using a particle bombardment device to deliver plasmid DNA into immature embryos and the regeneration of transgenic plants via somatic embryogenesis. Currently, this is the most commonly used method for transforming wheat and it offers some advantages. However, it will be interesting to see whether this position is challenged as facile methods are developed for delivering DNA by Agrobacterium tumefaciens or by the production of transformants via a germ-line process (see other chapters in this book).

Drosophila as a model system to unravel the layers of innate immunity to infection

PubMed Central

Kounatidis, Ilias; Ligoxygakis, Petros

2012-01-01

Summary Innate immunity relies entirely upon germ-line encoded receptors, signalling components and effector molecules for the recognition and elimination of invading pathogens. The fruit fly Drosophila melanogaster with its powerful collection of genetic and genomic tools has been the model of choice to develop ideas about innate immunity and host–pathogen interactions. Here, we review current research in the field, encompassing all layers of defence from the role of the microbiota to systemic immune activation, and attempt to speculate on future directions and open questions. PMID:22724070

Drosophila as a model system to unravel the layers of innate immunity to infection.

PubMed

Kounatidis, Ilias; Ligoxygakis, Petros

2012-05-01

Innate immunity relies entirely upon germ-line encoded receptors, signalling components and effector molecules for the recognition and elimination of invading pathogens. The fruit fly Drosophila melanogaster with its powerful collection of genetic and genomic tools has been the model of choice to develop ideas about innate immunity and host-pathogen interactions. Here, we review current research in the field, encompassing all layers of defence from the role of the microbiota to systemic immune activation, and attempt to speculate on future directions and open questions.

Circadian Rhythm Regulates Development of Enamel in Mouse Mandibular First Molar

PubMed Central

Tao, Jiang; Zhai, Yue; Park, Hyun; Han, Junli; Dong, Jianhui; Xie, Ming; Gu, Ting; Lewi, Keidren; Ji, Fang; Jia, William

2016-01-01

Rhythmic incremental growth lines and the presence of melatonin receptors were discovered in tooth enamel, suggesting possible role of circadian rhythm. We therefore hypothesized that circadian rhythm may regulate enamel formation through melatonin receptors. To test this hypothesis, we examined expression of melatonin receptors (MTs) and amelogenin (AMELX), a maker of enamel formation, during tooth germ development in mouse. Using qRT-PCR and immunocytochemistry, we found that mRNA and protein levels of both MTs and AMELX in normal mandibular first molar tooth germs increased gradually after birth, peaked at 3 or 4 day postnatal, and then decreased. Expression of MTs and AMELX by immunocytochemistry was significantly delayed in neonatal mice raised in all-dark or all-light environment as well as the enamel development. Furthermore, development of tooth enamel was also delayed showing significant immature histology in those animals, especially for newborn mice raised in all daylight condition. Interestingly, disruption in circadian rhythm in pregnant mice also resulted in delayed enamel development in their babies. Treatment with melatonin receptor antagonist 4P-PDOT in pregnant mice caused underexpression of MTs and AMELX associated with long-lasting deficiency in baby enamel tissue. Electromicroscopic evidence demonstrated increased necrosis and poor enamel mineralization in ameloblasts. The above results suggest that circadian rhythm is important for normal enamel development at both pre- and postnatal stages. Melatonin receptors were partly responsible for the regulation. PMID:27494172

Circadian Rhythm Regulates Development of Enamel in Mouse Mandibular First Molar.

PubMed

Tao, Jiang; Zhai, Yue; Park, Hyun; Han, Junli; Dong, Jianhui; Xie, Ming; Gu, Ting; Lewi, Keidren; Ji, Fang; Jia, William

2016-01-01

Rhythmic incremental growth lines and the presence of melatonin receptors were discovered in tooth enamel, suggesting possible role of circadian rhythm. We therefore hypothesized that circadian rhythm may regulate enamel formation through melatonin receptors. To test this hypothesis, we examined expression of melatonin receptors (MTs) and amelogenin (AMELX), a maker of enamel formation, during tooth germ development in mouse. Using qRT-PCR and immunocytochemistry, we found that mRNA and protein levels of both MTs and AMELX in normal mandibular first molar tooth germs increased gradually after birth, peaked at 3 or 4 day postnatal, and then decreased. Expression of MTs and AMELX by immunocytochemistry was significantly delayed in neonatal mice raised in all-dark or all-light environment as well as the enamel development. Furthermore, development of tooth enamel was also delayed showing significant immature histology in those animals, especially for newborn mice raised in all daylight condition. Interestingly, disruption in circadian rhythm in pregnant mice also resulted in delayed enamel development in their babies. Treatment with melatonin receptor antagonist 4P-PDOT in pregnant mice caused underexpression of MTs and AMELX associated with long-lasting deficiency in baby enamel tissue. Electromicroscopic evidence demonstrated increased necrosis and poor enamel mineralization in ameloblasts. The above results suggest that circadian rhythm is important for normal enamel development at both pre- and postnatal stages. Melatonin receptors were partly responsible for the regulation.

Functional tooth restoration utilising split germs through re-regionalisation of the tooth-forming field

PubMed Central

Yamamoto, Naomi; Oshima, Masamitsu; Tanaka, Chie; Ogawa, Miho; Nakajima, Kei; Ishida, Kentaro; Moriyama, Keiji; Tsuji, Takashi

2015-01-01

The tooth is an ectodermal organ that arises from a tooth germ under the regulation of reciprocal epithelial-mesenchymal interactions. Tooth morphogenesis occurs in the tooth-forming field as a result of reaction-diffusion waves of specific gene expression patterns. Here, we developed a novel mechanical ligation method for splitting tooth germs to artificially regulate the molecules that control tooth morphology. The split tooth germs successfully developed into multiple correct teeth through the re-regionalisation of the tooth-forming field, which is regulated by reaction-diffusion waves in response to mechanical force. Furthermore, split teeth erupted into the oral cavity and restored physiological tooth function, including mastication, periodontal ligament function and responsiveness to noxious stimuli. Thus, this study presents a novel tooth regenerative technology based on split tooth germs and the re-regionalisation of the tooth-forming field by artificial mechanical force. PMID:26673152

Human endogenous retrovirus rec interferes with germ cell development in mice and may cause carcinoma in situ, the predecessor lesion of germ cell tumors.

PubMed

Galli, Uwe M; Sauter, Marlies; Lecher, Bernd; Maurer, Simone; Herbst, Hermann; Roemer, Klaus; Mueller-Lantzsch, Nikolaus

2005-04-28

Germ cell tumors (GCTs) are among the most common malignancies in young men. We have previously documented that patients with GCT frequently produce serum antibodies directed against proteins encoded by human endogenous retrovirus (HERV) type K sequences. Transcripts originating from the env gene of HERV-K, including the rec-relative of human immunodeficiency virus rev, are highly expressed in GCTs. We report here that mice that inducibly express HERV-K rec show a disturbed germ cell development and may exhibit, by 19 months of age, changes reminiscent of carcinoma in situ, the predecessor lesion of classic seminoma in humans. This provides the first direct evidence that the expression of a human endogenous retroviral gene previously established as a marker in human germ cell tumors may contribute to organ-specific tumorigenesis in a transgenic mouse model.

Functional role of EMMPRIN in the formation and mineralisation of dental matrix in mouse molars.

PubMed

Xie, Ming; Xing, Guofang; Hou, Liwen; Bao, Jing; Chen, Yuqing; Jiao, Ting; Zhang, Fuqiang

2015-02-01

Our previous research has shown that the extracellular matrix metalloproteinase inducer (EMMPRIN) is expressed during and may function in the early development of tooth germs. In the present study, we observed the specific expression of EMMPRIN in ameloblasts and odontoblasts during the middle and late stages of tooth germ development using immunohistochemistry. Furthermore, to extend our understanding of the function of EMMPRIN in odontogenesis, we used an anti-EMMPRIN function-blocking antibody to remove EMMPRIN activity in tooth germ culture in vitro. Both the formation and mineralisation of dental hard tissues were suppressed in the tooth germ culture after the abrogation of EMMPRIN. Meanwhile, significant reductions in VEGF, MMP-9, ALPL, ameloblastin, amelogenin and enamelin expression were observed in antibody-treated tooth germ explants compared to control and normal serum-treated explants. The current results illustrate that EMMPRIN may play a critical role in the processing and maturation of the dental matrix.

DMRT1 Is Required for Mouse Spermatogonial Stem Cell Maintenance and Replenishment.

PubMed

Zhang, Teng; Oatley, Jon; Bardwell, Vivian J; Zarkower, David

2016-09-01

Male mammals produce sperm for most of postnatal life and therefore require a robust germ line stem cell system, with precise balance between self-renewal and differentiation. Prior work established doublesex- and mab-3-related transcription factor 1 (Dmrt1) as a conserved transcriptional regulator of male sexual differentiation. Here we investigate the role of Dmrt1 in mouse spermatogonial stem cell (SSC) homeostasis. We find that Dmrt1 maintains SSCs during steady state spermatogenesis, where it regulates expression of Plzf, another transcription factor required for SSC maintenance. We also find that Dmrt1 is required for recovery of spermatogenesis after germ cell depletion. Committed progenitor cells expressing Ngn3 normally do not contribute to SSCs marked by the Id4-Gfp transgene, but do so when spermatogonia are chemically depleted using busulfan. Removal of Dmrt1 from Ngn3-positive germ cells blocks the replenishment of Id4-GFP-positive SSCs and recovery of spermatogenesis after busulfan treatment. Our data therefore reveal that Dmrt1 supports SSC maintenance in two ways: allowing SSCs to remain in the stem cell pool under normal conditions; and enabling progenitor cells to help restore the stem cell pool after germ cell depletion.

Germ stem cells are active in postnatal mouse ovary under physiological conditions

PubMed Central

Guo, Kun; Li, Chao-hui; Wang, Xin-yi; He, Da-jian; Zheng, Ping

2016-01-01

STUDY HYPOTHESIS Are active ovarian germ stem cells present in postnatal mouse ovaries under physiological conditions? STUDY FINDING Active ovarian germ stem cells exist and function in adult mouse ovaries under physiological conditions. WHAT IS KNOWN ALREADY In vitro studies suggested the existence of germ stem cells in postnatal ovaries of mouse, pig and human. However, in vivo studies provided evidence against the existence of active germ stem cells in postnatal mouse ovaries. Thus, it remains controversial whether such germ stem cells really exist and function in vivo in postnatal mammalian ovaries. STUDY DESIGN, SAMPLES/MATERIALS, METHODS Octamer-binding transcription factor 4 (Oct4)-MerCreMer transgenic mice were crossed with R26R-enhanced yellow fluorescent protein (EYFP) mice to establish a tamoxifen-inducible tracing system so that Oct4-expressing potential ovarian germ stem cells in young adult mice (5–6 weeks old) can be labeled with EYFP. The germ cell activities of DNA replication, mitotic division, entry into meiosis and progression to primordial follicle stage were investigated by means of immunofluorescent staining of ovarian tissues collected at different time points post-tamoxifen injection (1 day, 3 days, 2 months and 4 months). Meiosis entry and primordial follicle formation were also measured by EYFP-labeled single-cell RT–PCR. Germ cell proliferation and mitotic division were examined through 5-bromodeoxyuridine triphosphate incorporation assay. At each time point, ovaries from two to three animals were used for each set of experiment. MAIN RESULTS AND THE ROLE OF CHANCE By labeling the Oct4-expressing small germ cells and tracing their fates for up to 4 months, we observed persistent meiosis entry and primordial follicle replenishment. Furthermore, we captured the transient processes of mitotic DNA replication as well as mitotic division of the marked germ cells at various time periods after tracing. These lines of evidence unambiguously support the presence of active germ stem cells in postnatal ovaries and their function in replenishing primordial follicle pool under physiological conditions. Moreover, we pointed out that Oct4+ deleted in azoospermia-like (Dazl)− but not Oct4+Dazl+ or Oct4+ DEAD (Asp–Glu–Ala–Asp) Box Polypeptide 4 (Ddx4)+ cells contain a population of germ stem cells in mouse ovary. LIMITATIONS, REASONS FOR CAUTION This study was conducted in mice. Whether or not the results are applicable to human remain unclear. The future work should aim at identifying the specific ovarian germ stem cell marker and evaluating the significance of these stem cells to normal ovarian function. WIDER IMPLICATIONS OF THE FINDINGS Clarifying the existence of active germ stem cells and their functional significance in postnatal mammalian ovaries could provide new insights in understanding the mechanism of ovarian aging and failure. LARGE SCALE DATA Not applicable. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by the National Key Basic Research Program of China (grant number 2012CBA01300) and the National Natural Science Foundation of China to P.Z. (31571484). No competing interests are reported. PMID:26916381

Cell junction dynamics in the testis: Sertoli-germ cell interactions and male contraceptive development.

PubMed

Cheng, C Yan; Mruk, Dolores D

2002-10-01

Spermatogenesis is an intriguing but complicated biological process. However, many studies since the 1960s have focused either on the hormonal events of the hypothalamus-pituitary-testicular axis or morphological events that take place in the seminiferous epithelium. Recent advances in biochemistry, cell biology, and molecular biology have shifted attention to understanding some of the key events that regulate spermatogenesis, such as germ cell apoptosis, cell cycle regulation, Sertoli-germ cell communication, and junction dynamics. In this review, we discuss the physiology and biology of junction dynamics in the testis, in particular how these events affect interactions of Sertoli and germ cells in the seminiferous epithelium behind the blood-testis barrier. We also discuss how these events regulate the opening and closing of the blood-testis barrier to permit the timely passage of preleptotene and leptotene spermatocytes across the blood-testis barrier. This is physiologically important since developing germ cells must translocate across the blood-testis barrier as well as traverse the seminiferous epithelium during their development. We also discuss several available in vitro and in vivo models that can be used to study Sertoli-germ cell anchoring junctions and Sertoli-Sertoli tight junctions. An in-depth survey in this subject has also identified several potential targets to be tackled to perturb spermatogenesis, which will likely lead to the development of novel male contraceptives.

Establishment of the Vertebrate Germ Layers.

PubMed

Tseng, Wei-Chia; Munisha, Mumingjiang; Gutierrez, Juan B; Dougan, Scott T

2017-01-01

The process of germ layer formation is a universal feature of animal development. The germ layers separate the cells that produce the internal organs and tissues from those that produce the nervous system and outer tissues. Their discovery in the early nineteenth century transformed embryology from a purely descriptive field into a rigorous scientific discipline, in which hypotheses could be tested by observation and experimentation. By systematically addressing the questions of how the germ layers are formed and how they generate overall body plan, scientists have made fundamental contributions to the fields of evolution, cell signaling, morphogenesis, and stem cell biology. At each step, this work was advanced by the development of innovative methods of observing cell behavior in vivo and in culture. Here, we take an historical approach to describe our current understanding of vertebrate germ layer formation as it relates to the long-standing questions of developmental biology. By comparing how germ layers form in distantly related vertebrate species, we find that highly conserved molecular pathways can be adapted to perform the same function in dramatically different embryonic environments.

[Turcot's syndrome confirmed by molecular biological tests].

PubMed

Jeannin, S; Lebrun, C; Van Den Bos, F; Olschwang, S; Bourg, V; Frenay, M

2006-06-01

Turcot's syndrome is characterized clinically by the concurrence of a primary brain tumor and a familial adenomatous polyposis or a hereditary nonpolyposis colorectal cancer. We report a case of a 45-year-old woman who underwent in 1995 neuro-oncological treatment for an anaplastic astrocytoma (grade III according to the World Health Organization classification). Treatment included complete surgery, radiotherapy, a first-line nitrosourea-based chemotherapy regimen and a second-line platinium salt-based regimen. It was then noted that the patient's brother had colorectal cancer. A genetic study detected a germ-line mutation on the hMSH2 gene specific of HNPCC syndrome (Human Non Polyposis Colorectal Cancer). Colonoscopy was normal. Eight years after the diagnosis, the patient developed a gliomatosis cerebri and died. Relevant personal and familial history can provide the clue to the diagnosis of Turcot's syndrome. Molecular diagnosis may contribute to appropriate care of affected patients.

The C. elegans VAPB homolog VPR-1 is a permissive signal for gonad development.

PubMed

Cottee, Pauline A; Cole, Tim; Schultz, Jessica; Hoang, Hieu D; Vibbert, Jack; Han, Sung Min; Miller, Michael A

2017-06-15

VAMP/synaptobrevin-associated proteins (VAPs) contain an N-terminal major sperm protein domain (MSPd) that is associated with amyotrophic lateral sclerosis. VAPs have an intracellular housekeeping function, as well as an extracellular signaling function mediated by the secreted MSPd. Here we show that the C. elegans VAP homolog VPR-1 is essential for gonad development. vpr-1 null mutants are maternal effect sterile due to arrested gonadogenesis following embryo hatching. Somatic gonadal precursor cells and germ cells fail to proliferate fully and complete their respective differentiation programs. Maternal or zygotic vpr-1 expression is sufficient to induce gonadogenesis and fertility. Genetic mosaic and cell type-specific expression studies indicate that vpr-1 activity is important in the nervous system, germ line and intestine. VPR-1 acts in parallel to Notch signaling, a key regulator of germline stem cell proliferation and differentiation. Neuronal vpr-1 expression is sufficient for gonadogenesis induction during a limited time period shortly after hatching. These results support the model that the secreted VPR-1 MSPd acts at least in part on gonadal sheath cell precursors in L1 to early L2 stage hermaphrodites to permit gonadogenesis. © 2017. Published by The Company of Biologists Ltd.

The C. elegans VAPB homolog VPR-1 is a permissive signal for gonad development

PubMed Central

Cole, Tim; Hoang, Hieu D.; Han, Sung Min

2017-01-01

VAMP/synaptobrevin-associated proteins (VAPs) contain an N-terminal major sperm protein domain (MSPd) that is associated with amyotrophic lateral sclerosis. VAPs have an intracellular housekeeping function, as well as an extracellular signaling function mediated by the secreted MSPd. Here we show that the C. elegans VAP homolog VPR-1 is essential for gonad development. vpr-1 null mutants are maternal effect sterile due to arrested gonadogenesis following embryo hatching. Somatic gonadal precursor cells and germ cells fail to proliferate fully and complete their respective differentiation programs. Maternal or zygotic vpr-1 expression is sufficient to induce gonadogenesis and fertility. Genetic mosaic and cell type-specific expression studies indicate that vpr-1 activity is important in the nervous system, germ line and intestine. VPR-1 acts in parallel to Notch signaling, a key regulator of germline stem cell proliferation and differentiation. Neuronal vpr-1 expression is sufficient for gonadogenesis induction during a limited time period shortly after hatching. These results support the model that the secreted VPR-1 MSPd acts at least in part on gonadal sheath cell precursors in L1 to early L2 stage hermaphrodites to permit gonadogenesis. PMID:28634273

Transcriptome analysis reveals differentially expressed genes associated with germ cell and gonad development in the Southern bluefin tuna (Thunnus maccoyii).

PubMed

Bar, Ido; Cummins, Scott; Elizur, Abigail

2016-03-10

Controlling and managing the breeding of bluefin tuna (Thunnus spp.) in captivity is an imperative step towards obtaining a sustainable supply of these fish in aquaculture production systems. Germ cell transplantation (GCT) is an innovative technology for the production of inter-species surrogates, by transplanting undifferentiated germ cells derived from a donor species into larvae of a host species. The transplanted surrogates will then grow and mature to produce donor-derived seed, thus providing a simpler alternative to maintaining large-bodied broodstock such as the bluefin tuna. Implementation of GCT for new species requires the development of molecular tools to follow the fate of the transplanted germ cells. These tools are based on key reproductive and germ cell-specific genes. RNA-Sequencing (RNA-Seq) provides a rapid, cost-effective method for high throughput gene identification in non-model species. This study utilized RNA-Seq to identify key genes expressed in the gonads of Southern bluefin tuna (Thunnus maccoyii, SBT) and their specific expression patterns in male and female gonad cells. Key genes involved in the reproductive molecular pathway and specifically, germ cell development in gonads, were identified using analysis of RNA-Seq transcriptomes of male and female SBT gonad cells. Expression profiles of transcripts from ovary and testis cells were compared, as well as testis germ cell-enriched fraction prepared with Percoll gradient, as used in GCT studies. Ovary cells demonstrated over-expression of genes related to stem cell maintenance, while in testis cells, transcripts encoding for reproduction-associated receptors, sex steroids and hormone synthesis and signaling genes were over-expressed. Within the testis cells, the Percoll-enriched fraction showed over-expression of genes that are related to post-meiosis germ cell populations. Gonad development and germ cell related genes were identified from SBT gonads and their expression patterns in ovary and testis cells were determined. These expression patterns correlate with the reproductive developmental stage of the sampled fish. The majority of the genes described in this study were sequenced for the first time in T. maccoyii. The wealth of SBT gonadal and germ cell-related gene sequences made publicly available by this study provides an extensive resource for further GCT and reproductive molecular biology studies of this commercially valuable fish.

INDUCED AND SPONTANEOUS NEOPLASIA IN ZEBRAFISH.

EPA Science Inventory

To address the potential of zebrafish as a cancer model, it is important to determine the susceptibility of zebrafish to tumors, and to compare zebrafish tumors with human tumors. To determine whether the commonly-used germ line mutagen, ethylnitrosourea (ENU) induces tumors, we ...

Function of Piwi, a nuclear Piwi/Argonaute protein, is independent of its slicer activity.

PubMed

Darricarrère, Nicole; Liu, Na; Watanabe, Toshiaki; Lin, Haifan

2013-01-22

The Piwi protein subfamily is essential for Piwi-interacting RNA (piRNA) biogenesis, transposon silencing, and germ-line development, all of which have been proposed to require Piwi endonuclease activity, as validated for two cytoplasmic Piwi proteins in mice. However, recent evidence has led to questioning of the generality of this mechanism for the Piwi members that reside in the nucleus. Drosophila offers a distinct opportunity to study the function of nuclear Piwi proteins because, among three Drosophila Piwi proteins--called Piwi, Aubergine, and Argonaute 3--Piwi is the only member of this subfamily that is localized in the nucleus and expressed in both germ-line and somatic cells in the gonad, where it is responsible for piRNA biogenesis and regulatory functions essential for fertility. In this study, we demonstrate beyond doubt that the slicer activity of Piwi is not required for any known functions in vivo. We show that, in transgenic flies with the DDX catalytic triad of PIWI mutated, neither primary nor secondary piRNA biogenesis is detectably affected, transposons remain repressed, and fertility is normal. Our observations demonstrate that the mechanism of Piwi is independent of its in vitro endonuclease activity. Instead, it is consistent with the alternative mode of Piwi function as a molecule involved in the piRNA-directed guidance of epigenetic factors to chromatin.

Evolutionary aspects of the development of teeth and baleen in the bowhead whale.

PubMed

Thewissen, J G M; Hieronymus, Tobin L; George, John C; Suydam, Robert; Stimmelmayr, Raphaela; McBurney, Denise

2017-04-01

In utero, baleen whales initiate the development of several dozens of teeth in upper and lower jaws. These tooth germs reach the bell stage and are sometimes mineralized, but toward the end of prenatal life they are resorbed and no trace remains after birth. Around the time that the germs disappear, the keratinous baleen plates start to form in the upper jaw, and these form the food-collecting mechanism. Baleen whale ancestors had two generations of teeth and never developed baleen, and the prenatal teeth of modern fetuses are usually interpreted as an evolutionary leftover. We investigated the development of teeth and baleen in bowhead whale fetuses using histological and immunohistochemical evidence. We found that upper and lower dentition initially follow similar developmental pathways. As development proceeds, upper and lower tooth germs diverge developmentally. Lower tooth germs differ along the length of the jaw, reminiscent of a heterodont dentition of cetacean ancestors, and lingual processes of the dental lamina represent initiation of tooth bud formation of replacement teeth. Upper tooth germs remain homodont and there is no evidence of a secondary dentition. After these germs disappear, the oral epithelium thickens to form the baleen plates, and the protein FGF-4 displays a signaling pattern reminiscent of baleen plates. In laboratory mammals, FGF-4 is not involved in the formation of hair or palatal rugae, but it is involved in tooth development. This leads us to propose that the signaling cascade that forms teeth in most mammals has been exapted to be involved in baleen plate ontogeny in mysticetes. © 2017 Anatomical Society.

Activation of the germ-cell potential of human bone marrow-derived cells by a chemical carcinogen

PubMed Central

Liu, Chunfang; Ma, Zhan; Xu, Songtao; Hou, Jun; Hu, Yao; Yu, Yinglu; Liu, Ruilai; Chen, Zhihong; Lu, Yuan

2014-01-01

Embryonic/germ cell traits are common in malignant tumors and are thought to be involved in malignant tumor behaviors. The reasons why tumors show strong embryonic/germline traits (displaced germ cells or gametogenic programming reactivation) are controversial. Here, we show that a chemical carcinogen, 3-methyl-cholanthrene (3-MCA), can trigger the germ-cell potential of human bone marrow-derived cells (hBMDCs). 3-MCA promoted the generation of germ cell-like cells from induced hBMDCs that had undergone malignant transformation, whereas similar results were not observed in the parallel hBMDC culture at the same time point. The malignant transformed hBMDCs spontaneously and more efficiently generated into germ cell-like cells even at the single-cell level. The germ cell-like cells from induced hBMDCs were similar to natural germ cells in many aspects, including morphology, gene expression, proliferation, migration, further development, and teratocarcinoma formation. Therefore, our results demonstrate that a chemical carcinogen can reactivate the germline phenotypes of human somatic tissue-derived cells, which might provide a novel idea to tumor biology and therapy. PMID:24998261

Differentiation of female Oct4-GFP embryonic stem cells into germ lineage cells.

PubMed

Ma, Xin; Li, Peng; Sun, Xiang; Sun, Yifeng; Hu, Rong; Yuan, Ping

2018-04-01

Due to high infertility ratio nowadays, it is essential to explore efficient ways of enhancing mammalian reproductivity, in particular female reproductivity. Using female Oct4-GFP embryonic stem cells, we mimic the in vivo development procedure to induce ES cells into epiblast cell-like cells (EpiLCs) and then primordial germ cell-like cells (PGCLCs). GFP positive PGCLCs that showed typical PGC markers and epigenetic modification were efficiently obtained. Further transplantation of the GFP positive PGCLC and native ovary cell mixture into ovary of infertile mice revealed that both MVH and GFP positive cells could be developed in ovary, but no later developmental stage germ cells were observed. This study suggested that Oct4-GFP ES cells may be only suitable for tracing early germ cell development. © 2018 International Federation for Cell Biology.

Effect of fetal or neonatal exposure to monobutyl phthalate (MBP) on testicular development and function in the marmoset

PubMed Central

McKinnell, Chris; Mitchell, Rod T.; Walker, Marion; Morris, Keith; Kelnar, Chris J.H.; Wallace, W. Hamish; Sharpe, Richard M.

2009-01-01

BACKGROUND Fetal exposure of male rats to some phthalates induces reproductive abnormalities, raising concerns for similar effects in humans. In order to address this in a more appropriate animal model, the aim of the present studies was to investigate the effect of fetal/neonatal exposure to monobutyl phthalate (MBP) in a non-human primate, the marmoset. In particular, to determine if exposure resulted in effects at birth, or in adulthood, similar to those in male rats, and whether there was evidence for induction of carcinoma-in-situ (CIS) or testicular germ cell tumours (TGCT). METHODS Pregnant female marmosets were dosed from ∼7–15 weeks gestation with 500 mg/kg/day MBP and male offspring studied at birth (1–5 days; n = 6) or in adulthood (n = 5). In another study, newborn males (n = 5 co-twins) were dosed with 500 mg/kg/day MBP for 14 days, commencing at ∼4 days of age. RESULTS Fetal exposure of marmosets to MBP did not affect gross testicular morphology, reproductive tract development or testosterone levels at birth, nor were germ cell number and proliferation, Sertoli cell number or germ:Sertoli cell ratio affected. In two of six MBP-exposed animals, unusual clusters of undifferentiated germ cells were found, but their significance is unclear. Neonatal MBP treatment did not affect germ cell numbers or differentiation. Fetal exposure to MBP did not affect testis size/morphology, germ cell numbers or fertility in adulthood. There was no evidence for CIS or TGCT. CONCLUSIONS Fetal exposure of marmosets to MBP does not measurably affect testis development/function or cause testicular dysgenesis, and no effects emerge by adulthood. Some effects on germ cell development were found, but these were inconsistent and of uncertain significance. PMID:19491204

Effects of the tumor-vasculature-disrupting agent verubulin and two heteroaryl analogues on cancer cells, endothelial cells, and blood vessels.

PubMed

Mahal, Katharina; Resch, Marcus; Ficner, Ralf; Schobert, Rainer; Biersack, Bernhard; Mueller, Thomas

2014-04-01

Two analogues of the discontinued tumor vascular-disrupting agent verubulin (Azixa®, MPC-6827, 1) featuring benzo-1,4-dioxan-6-yl (compound 5 a) and N-methylindol-5-yl (compound 10) residues instead of the para-anisyl group on the 4-(methylamino)-2-methylquinazoline pharmacophore, were prepared and found to exceed the antitumor efficacy of the lead compound. They were antiproliferative with single-digit nanomolar IC50 values against a panel of nine tumor cell lines, while not affecting nonmalignant fibroblasts. Indole 10 surpassed verubulin in seven tumor cell lines including colon, breast, ovarian, and germ cell cancer cell lines. In line with docking studies indicating that compound 10 may bind the colchicine binding site of tubulin more tightly (Ebind =-9.8 kcal mol(-1) ) than verubulin (Ebind =-8.3 kcal mol(-1) ), 10 suppressed the formation of vessel-like tubes in endothelial cells and destroyed the blood vessels in the chorioallantoic membrane of fertilized chicken eggs at nanomolar concentrations. When applied to nude mice bearing a highly vascularized 1411HP germ cell xenograft tumor, compound 10 displayed pronounced vascular-disrupting effects that led to hemorrhages and extensive central necrosis in the tumor. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

NANOG priming before full reprogramming may generate germ cell tumours.

PubMed

Grad, I; Hibaoui, Y; Jaconi, M; Chicha, L; Bergström-Tengzelius, R; Sailani, M R; Pelte, M F; Dahoun, S; Mitsiadis, T A; Töhönen, V; Bouillaguet, S; Antonarakis, S E; Kere, J; Zucchelli, M; Hovatta, O; Feki, A

2011-11-09

Reprogramming somatic cells into a pluripotent state brings patient-tailored, ethical controversy-free cellular therapy closer to reality. However, stem cells and cancer cells share many common characteristics; therefore, it is crucial to be able to discriminate between them. We generated two induced pluripotent stem cell (iPSC) lines, with NANOG pre-transduction followed by OCT3/4, SOX2, and LIN28 overexpression. One of the cell lines, CHiPS W, showed normal pluripotent stem cell characteristics, while the other, CHiPS A, though expressing pluripotency markers, failed to differentiate and gave rise to germ cell-like tumours in vivo. Comparative genomic hybridisation analysis of the generated iPS lines revealed that they were genetically more stable than human embryonic stem cell counterparts. This analysis proved to be predictive for the differentiation potential of analysed cells. Moreover, the CHiPS A line expressed a lower ratio of p53/p21 when compared to CHiPS W. NANOG pre-induction followed by OCT3/4, SOX2, MYC, and KLF4 induction resulted in the same tumour-inducing phenotype. These results underline the importance of a re-examination of the role of NANOG during reprogramming. Moreover, this reprogramming method may provide insights into primordial cell tumour formation and cancer stem cell transformation.

The developmental basis for germline mosaicism in mouse and Drosophila melanogaster.

PubMed

Drost, J B; Lee, W R

1998-01-01

Data involving germline mosaics in Drosophila melanogaster and mouse are reconciled with developmental observations. Mutations that become fixed in the early embryo before separation of soma from the germline may, by the sampling process of development, continue as part of germline and/or differentiate into any somatic tissue. The cuticle of adult D. melanogaster, because of segmental development, can be used to estimate the proportion of mutant nuclei in the early embryo, but most somatic tissues and the germlines of both species continue from samples too small to be representative of the early embryo. Because of the small sample of cells/nuclei that remain in the germline after separation of soma in both species, mosaic germlines have percentages of mutant cells that vary widely, with a mean of 50% and an unusual platykurtic, flat-topped distribution. While the sampling process leads to similar statistical results for both species, their patterns of development are very different. In D. melanogaster the first differentiation is the separation of soma from germline with the germline continuing from a sample of only two to four nuclei, whereas the adult cuticle is a representative sample of cleavage nuclei. The presence of mosaicism in D. melanogaster germline is independent of mosaicism in the eye, head, and thorax. This independence was used to determine that mutations can occur at any of the early embryonic cell divisions and still average 50% mutant germ cells when the germline is mosaic; however, the later the mutation occurs, the higher the proportion of completely nonmutant germlines. In contrast to D. melanogaster, the first differentiation in the mouse does not separate soma from germline but produces the inner cell mass that is representative of the cleavage nuclei. Following formation of the primitive streak, the primordial germ cells develop at the base of the allantois and among a clonally related sample of cells, providing the same statistical distribution in the mouse germlines as in D. melanogaster. The proportion of mutations that are fixed during early embryonic development is greatly underestimated. For example, a DNA lesion in a postmeiotic gamete that becomes fixed as a dominant mutation during early embryonic development of the F1 may produce an individual completely mutant in the germ line and relevant somatic tissue or, alternatively, the F1 germline may be completely mutant but with no relevant somatic tissues for detecting the mutation until the F2. In both cases the mutation would be classified as complete in the F1 and F2, respectively, and not recognized as embryonic in origin. Because germ cells differentiate later in mammalian development, there are more opportunities for correlation between germline and soma in the mammal than Drosophila. However, because the germ cells and any somatic tissue, like blood, are derived from small samples, there may be many individuals that test negative in blood but have germlines that are either mosaic or entirely mutant.

ApcMin, A Mutation in the Murine Apc Gene, Predisposes to Mammary Carcinomas and Focal Alveolar Hyperplasias

NASA Astrophysics Data System (ADS)

Moser, Amy Rapaich; Mattes, Ellen M.; Dove, William F.; Lindstrom, Mary J.; Haag, Jill D.; Gould, Michael N.

1993-10-01

ApcMin (Min, multiple intestinal neoplasia) is a point mutation in the murine homolog of the APC gene. Min/+ mice develop multiple intestinal adenomas, as do humans carrying germ-line mutations in APC. Female mice carrying Min are also prone to develop mammary tumors. Min/+ mammary glands are more sensitive to chemical carcinogenesis than are +/+ mammary glands. Transplantation of mammary cells from Min/+ or +/+ donors into +/+ hosts demonstrates that the propensity to develop mammary tumors is intrinsic to the Min/+ mammary cells. Long-term grafts of Min/+ mammary glands also gave rise to focal alveolar hyperplasias, indicating that the presence of the Min mutation also has a role in the development of these lesions.

Specifying and protecting germ cell fate

PubMed Central

Strome, Susan; Updike, Dustin

2015-01-01

Germ cells are the special cells in the body that undergo meiosis to generate gametes and subsequently entire new organisms after fertilization, a process that continues generation after generation. Recent studies have expanded our understanding of the factors and mechanisms that specify germ cell fate, including the partitioning of maternally supplied ‘germ plasm’, inheritance of epigenetic memory and expression of transcription factors crucial for primordial germ cell (PGC) development. Even after PGCs are specified, germline fate is labile and thus requires protective mechanisms, such as global transcriptional repression, chromatin state alteration and translation of only germline-appropriate transcripts. Findings from diverse species continue to provide insights into the shared and divergent needs of these special reproductive cells. PMID:26122616

An in vitro model demonstrates the potential of neoplastic human germ cells to influence the tumour microenvironment.

PubMed

Klein, B; Schuppe, H-C; Bergmann, M; Hedger, M P; Loveland, B E; Loveland, K L

2017-07-01

Testicular germ cell tumours (TGCT) typically contain high numbers of infiltrating immune cells, yet the functional nature and consequences of interactions between GCNIS (germ cell neoplasia in situ) or seminoma cells and immune cells remain unknown. A co-culture model using the seminoma-derived TCam-2 cell line and peripheral blood mononuclear cells (PBMC, n = 7 healthy donors) was established to investigate how tumour and immune cells each contribute to the cytokine microenvironment associated with TGCT. Three different co-culture approaches were employed: direct contact during culture to simulate in situ cellular interactions occurring within seminomas (n = 9); indirect contact using well inserts to mimic GCNIS, in which a basement membrane separates the neoplastic germ cells and immune cells (n = 3); and PBMC stimulation prior to direct contact during culture to overcome the potential lack of immune cell activation (n = 3). Transcript levels for key cytokines in PBMC and TCam-2 cell fractions were determined using RT-qPCR. TCam-2 cell fractions showed an immediate increase (within 24 h) in several cytokine mRNAs after direct contact with PBMC, whereas immune cell fractions did not. The high levels of interleukin-6 (IL6) mRNA and protein associated with TCam-2 cells implicate this cytokine as important to seminoma physiology. Use of PBMCs from different donors revealed a robust, repeatable pattern of changes in TCam-2 and PBMC cytokine mRNAs, independent of potential inter-donor variation in immune cell responsiveness. This in vitro model recapitulated previous data from clinical TGCT biopsies, revealing similar cytokine expression profiles and indicating its suitability for exploring the in vivo circumstances of TGCT. Despite the limitations of using a cell line to mimic in vivo events, these results indicate how neoplastic germ cells can directly shape the surrounding tumour microenvironment, including by influencing local immune responses. IL6 production by seminoma cells may be a practical target for early diagnosis and/or treatment of TGCT. © 2017 American Society of Andrology and European Academy of Andrology.

Minichromosome maintenance helicase paralog MCM9 is dispensible for DNA replication but functions in germ-line stem cells and tumor suppression.

PubMed

Hartford, Suzanne A; Luo, Yunhai; Southard, Teresa L; Min, Irene M; Lis, John T; Schimenti, John C

2011-10-25

Effective DNA replication is critical to the health and reproductive success of organisms. The six MCM2-7 proteins, which form the replicative helicase, are essential for high-fidelity replication of the genome. Many eukaryotes have a divergent paralog, MCM9, that was reported to be essential for loading MCM2-7 onto replication origins in the Xenopus oocyte extract system. To address the in vivo role of mammalian MCM9, we created and analyzed the phenotypes of mice with various mutations in Mcm9 and an intronic DNA replication-related gene Asf1a. Ablation of Mcm9 was compatible with cell proliferation and mouse viability, showing that it is nonessential for MCM2-7 loading or DNA replication. Mcm9 mutants underwent p53-independent embryonic germ-cell depletion in both sexes, with males also exhibiting defective spermatogonial stem-cell renewal. MCM9-deficient cells had elevated genomic instability and defective cell cycle reentry following replication stress, and mutant animals were prone to sex-specific cancers, most notably hepatocellular carcinoma in males. The phenotypes of mutant mice and cells suggest that MCM9 evolved a specialized but nonessential role in DNA replication or replication-linked quality-control mechanisms that are especially important for germ-line stem cells, and also for tumor suppression and genome maintenance in the soma.

Distinct and Cooperative Roles of amh and dmrt1 in Self-Renewal and Differentiation of Male Germ Cells in Zebrafish.

PubMed

Lin, Qiaohong; Mei, Jie; Li, Zhi; Zhang, Xuemei; Zhou, Li; Gui, Jian-Fang

2017-11-01

Spermatogenesis is a fundamental process in male reproductive biology and depends on precise balance between self-renewal and differentiation of male germ cells. However, the regulative factors for controlling the balance are poorly understood. In this study, we examined the roles of amh and dmrt1 in male germ cell development by generating their mutants with Crispr/Cas9 technology in zebrafish. Amh mutant zebrafish displayed a female-biased sex ratio, and both male and female amh mutants developed hypertrophic gonads due to uncontrolled proliferation and impaired differentiation of germ cells. A large number of proliferating spermatogonium-like cells were observed within testicular lobules of the amh -mutated testes, and they were demonstrated to be both Vasa- and PH3-positive. Moreover, the average number of Sycp3- and Vasa-positive cells in the amh mutants was significantly lower than in wild-type testes, suggesting a severely impaired differentiation of male germ cells. Conversely, all the dmrt1 -mutated testes displayed severe testicular developmental defects and gradual loss of all Vasa-positive germ cells by inhibiting their self-renewal and inducing apoptosis. In addition, several germ cell and Sertoli cell marker genes were significantly downregulated, whereas a prominent increase of Insl3-positive Leydig cells was revealed by immunohistochemical analysis in the disorganized dmrt1 -mutated testes. Our data suggest that amh might act as a guardian to control the balance between proliferation and differentiation of male germ cells, whereas dmrt1 might be required for the maintenance, self-renewal, and differentiation of male germ cells. Significantly, this study unravels novel functions of amh gene in fish. Copyright © 2017 by the Genetics Society of America.

A Novel Dynamic Expression of vasa in Male Germ Cells during Spermatogenesis in the Chinese Soft-Shell Turtle (Pelidiscus sinensis).

PubMed

Li, Wei; Zhang, Piaoyi; Wu, Xuling; Zhu, Xinping; Xu, Hongyan

2017-05-01

vasa gene encodes a highly conserved DEAD-box RNA helicase, required for germ cell development across animal kingdom. Vasa mutations cause male infertility in mammals. It has been widely used as a biomarker for studying animal fertility or manipulating germ cells in organisms. However, in reptilians, the functions of vasa gene involved in germ cell differentiation are largely unclear; this hampers the development of biological techniques and the improvement of the productivity in these species. Here a vasa cDNA was isolated in Chinese soft-shell turtle and it predicts a protein of 691 amino acid residues, which is 72%, 69%, 58%, 59%, and 54-56% identical to its homolog from mouse, platypus, frog, chicken, and fish, respectively, and named as PsVasa. The Psvasa mRNA was detected exclusively in the gonads of both sexes by RT-PCR. Chromogenic RNA in situ hybridization revealed that the Psvasa mRNA was restricted to germ cells in the testis: The psvasa mRNA is undetectable in resting spermatogonia, appears in proliferating spermatogonia, and becomes abundant in spermatocytes and detectable in spermatozoa. Immunofluorescence staining demonstrated that the PsVasa in the testis is also restricted to the germ cells, rich in spermatocytes and elongated spermatids but hardly detectable in spermatogonia and spermatozoa. Taken together, Psvasa is potentially a reliable germ cell marker in the Chinese soft-shell turtle; its RNA expression could distinguish the different spermatogenic stages of germ cells. These findings shed new insights into understanding the evolutionary conservations and divergences of vasa gene's functions in male germ cell differentiation in metazoans. © 2017 Wiley Periodicals, Inc.

Metachronous Testicular Cancer After Orchiectomy: A Rare Case.

PubMed

Arda, Ersan; Cakiroglu, Basri; Cetin, Gizem; Yuksel, Ilkan

2017-11-09

Testicular cancer represents approximately 1% of all cancers diagnosed in males. The prevalence of bilateral testicular germ cell tumor cases varies from 1% to 5%. Intratubular germ cell neoplasia (ITGCN) is a precursor for almost all testicular germ cell tumors (TGCT) and is one of the highest risks of developing contralateral testicular cancer. The radical orchiectomy is still preferred for the treatment of testicular cancer. However, in some cases like solitary testis, bilateral cancer or if the tumor size is under 30% percent of the testicular extent, organ-sparing surgery can be an option. There are just a few published reports of metachronous contralateral testicular cancer, developed after orchiectomy with the histopathology of the intratubular germ cell neoplasia.

Germ Cell Development in the Scleractinian Coral Euphyllia ancora (Cnidaria, Anthozoa)

PubMed Central

Shikina, Shinya; Chen, Chieh-Jhen; Liou, Jhe-Yu; Shao, Zi-Fan; Chung, Yi-Jou; Lee, Yan-Horn; Chang, Ching-Fong

2012-01-01

Sexual reproduction of scleractinian coral is among the most important means of establishing coral populations. However, thus far, little is known about the mechanisms underlying coral gametogenesis. To better understand coral germ cell development, we performed a histological analysis of gametogenesis in Euphyllia ancora and characterized the coral homolog of the Drosophila germline marker gene vasa. The histological analysis revealed that E. ancora gametogenesis occurs in the mesenterial mesoglea between the mesenterial filaments and the retractor muscle bands. The development of germ cells takes approximately one year in females and half a year in males. Staining of tissue sections with an antibody against E. ancora Vasa (Eavas) revealed anti-Eavas immunoreactivity in the oogonia, early oocyte, and developing oocyte, but only faint or undetectable reactivity in developing oocytes that were >150 µm in diameters. In males, Eavas could be detected in the spermatogonia and primary spermatocytes but was only faintly detectable in the secondary spermatocytes, spermatids, and sperms. Furthermore, a reverse transcription-polymerase chain reaction analysis and Western blotting analysis of unfertilized mature eggs proved the presence of Eavas transcripts and proteins, suggesting that Eavas may be a maternal factor. Vasa may represent a germ cell marker for corals, and would allow us to distinguish germ cells from somatic cells in coral bodies that have no distinct organs. PMID:22848529

Germ cell development in the scleractinian coral Euphyllia ancora (Cnidaria, Anthozoa).

PubMed

Shikina, Shinya; Chen, Chieh-Jhen; Liou, Jhe-Yu; Shao, Zi-Fan; Chung, Yi-Jou; Lee, Yan-Horn; Chang, Ching-Fong

2012-01-01

Sexual reproduction of scleractinian coral is among the most important means of establishing coral populations. However, thus far, little is known about the mechanisms underlying coral gametogenesis. To better understand coral germ cell development, we performed a histological analysis of gametogenesis in Euphyllia ancora and characterized the coral homolog of the Drosophila germline marker gene vasa. The histological analysis revealed that E. ancora gametogenesis occurs in the mesenterial mesoglea between the mesenterial filaments and the retractor muscle bands. The development of germ cells takes approximately one year in females and half a year in males. Staining of tissue sections with an antibody against E. ancora Vasa (Eavas) revealed anti-Eavas immunoreactivity in the oogonia, early oocyte, and developing oocyte, but only faint or undetectable reactivity in developing oocytes that were >150 µm in diameters. In males, Eavas could be detected in the spermatogonia and primary spermatocytes but was only faintly detectable in the secondary spermatocytes, spermatids, and sperms. Furthermore, a reverse transcription-polymerase chain reaction analysis and Western blotting analysis of unfertilized mature eggs proved the presence of Eavas transcripts and proteins, suggesting that Eavas may be a maternal factor. Vasa may represent a germ cell marker for corals, and would allow us to distinguish germ cells from somatic cells in coral bodies that have no distinct organs.

Biolistic transformation of cotton zygotic embryo meristem

USDA-ARS?s Scientific Manuscript database

Biolistic transformation of cotton meristems, isolated from mature seed is detailed in this book chapter. This method is simple and avoids the necessity to use genotype-dependent regenerable cell cultures. However, identification of germ line transformation using this method is laborious and time-c...

Multigenerational effects of maternal undernutrition

PubMed Central

Einstein, Francine H.

2014-01-01

Intrauterine exposure to reduced nutrient availability can have major effects in determining susceptibility to chronic disease later in life. Martínez et al. (2014) demonstrate multigenerational effects of poor maternal nutrition and evidence of germ-line transmission through alterations in DNA methylation. PMID:24896533

Multicellularity makes somatic differentiation evolutionarily stable

PubMed Central

Wahl, Mary E.; Murray, Andrew W.

2016-01-01

Many multicellular organisms produce two cell lineages: germ cells, whose descendants produce the next generation, and somatic cells, which support, protect, and disperse the germ cells. This germ-soma demarcation has evolved independently in dozens of multicellular taxa but is absent in unicellular species. A common explanation holds that in these organisms, inefficient intercellular nutrient exchange compels the fitness cost of producing nonreproductive somatic cells to outweigh any potential benefits. We propose instead that the absence of unicellular, soma-producing populations reflects their susceptibility to invasion by nondifferentiating mutants that ultimately eradicate the soma-producing lineage. We argue that multicellularity can prevent the victory of such mutants by giving germ cells preferential access to the benefits conferred by somatic cells. The absence of natural unicellular, soma-producing species previously prevented these hypotheses from being directly tested in vivo: to overcome this obstacle, we engineered strains of the budding yeast Saccharomyces cerevisiae that differ only in the presence or absence of multicellularity and somatic differentiation, permitting direct comparisons between organisms with different lifestyles. Our strains implement the essential features of irreversible conversion from germ line to soma, reproductive division of labor, and clonal multicellularity while maintaining sufficient generality to permit broad extension of our conclusions. Our somatic cells can provide fitness benefits that exceed the reproductive costs of their production, even in unicellular strains. We find that nondifferentiating mutants overtake unicellular populations but are outcompeted by multicellular, soma-producing strains, suggesting that multicellularity confers evolutionary stability to somatic differentiation. PMID:27402737

Germ cell tumors: Insights from the Drosophila ovary and the mouse testis

PubMed Central

Salz, Helen K.; Dawson, Emily P.; Heaney, Jason D.

2017-01-01

SUMMARY Ovarian and testicular germ cell tumors of young adults are thought to arise from defects in germ cell development, but the molecular mechanisms underlying malignant transformation are poorly understood. In this review, we focus on the biology of germ cell tumor formation in the Drosophila ovary and the mouse testis, for which the evidence supports common underlying mechanisms such as blocking initiation into the differentiation pathway, impaired lineage progression, and sexual identity instability. We then discuss how these concepts inform our understanding of the disease in humans. PMID:28079292

Germ cell specification and ovary structure in the rotifer Brachionus plicatilis.

PubMed

Smith, James M; Cridge, Andrew G; Dearden, Peter K

2010-08-02

The segregation of the germline from somatic tissues is an essential process in the development of all animals. Specification of the primordial germ cells (PGCs) takes place via different strategies across animal phyla; either specified early in embryogenesis by the inheritance of maternal determinants in the cytoplasm of the oocyte ('preformation') or selected later in embryonic development from undifferentiated precursors by a localized inductive signal ('epigenesis'). Here we investigate the specification and development of the germ cells in the rotifer Brachionus plicatilis, a member of the poorly-characterized superphyla Lophotrochozoa, by isolating the Brachionus homologues of the conserved germ cell markers vasa and nanos, and examining their expression using in situ hybridization. Bpvasa and Bpnos RNA expression have very similar distributions in the Brachionus ovary, showing ubiquitous expression in the vitellarium, with higher levels in the putative germ cell cluster. Bpvas RNA expression is present in freshly laid eggs, remaining ubiquitous in embryos until at least the 96 cell stage after which expression narrows to a small cluster of cells at the putative posterior of the embryo, consistent with the developing ovary. Bpnos RNA expression is also present in just-laid eggs but expression is much reduced by the four-cell stage and absent by the 16-cell stage. Shortly before hatching of the juvenile rotifer from the egg, Bpnos RNA expression is re-activated, located in a subset of posterior cells similar to those expressing Bpvas at the same stage. The observed expression of vasa and nanos in the developing B. plicatilis embryo implies an epigenetic origin of primordial germ cells in Rotifer.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Villalba, Miryam I.; Canul-Tec, Juan C.; Luna-Martínez, Oscar D.

Light chain amyloidosis (AL) is a disease that affects vital organs by the fibrillar aggregation of monoclonal light chains. λ3r germ line is significantly implicated in this disease. In this paper, we contrasted the thermodynamic stability and aggregation propensity of 3mJL2 (nonamyloidogenic) and 3rJL2 (amyloidogenic) λ3 germ lines. Because of an inherent limitation (extremely low expression), Cys at position 34 of the 3r germ line was replaced by Tyr reaching a good expression yield. A second substitution (W91A) was introduced in 3r to obtain a better template to incorporate additional mutations. Although the single mutant (C34Y) was not fibrillogenic, themore » second mutation located at CDR3 (W91A) induced fibrillogenesis. We propose, for the first time, that CDR3 (position 91) affects the stability and fiber formation of human λ3r light chains. Using the double mutant (3rJL2/YA) as template, other variants were constructed to evaluate the importance of those substitutions into the stability and aggregation propensity of λ3 light chains. A change in position 7 (P7D) boosted 3rJL2/YA fibrillogenic properties. Modification of position 48 (I48M) partially reverted 3rJL2/YA fibril aggregation. Finally, changes at positions 8 (P8S) or 40 (P40S) completely reverted fibril formation. These results confirm the influential roles of N-terminal region (positions 7 and 8) and the loop 40–60 (positions 40 and 48) on AL. X-ray crystallography revealed that the three-dimensional topology of the single and double λ3r mutants was not significantly altered. Finally, this mutagenic approach helped to identify key regions implicated in λ3 AL.« less

Association of low-risk MSH3 and MSH2 variant alleles with Lynch syndrome: probability of synergistic effects.

PubMed

Duraturo, Francesca; Liccardo, Raffaella; Cavallo, Angela; De Rosa, Marina; Grosso, Michela; Izzo, Paola

2011-10-01

Mutations in the MLH1 and MSH2 genes account for a majority of cases of families with Lynch Syndrome. Germ-line mutations in MSH6, PMS2 and MLH3 are responsible for disease in a minority of cases, usually associated with milder and variable phenotypes. No germ-line mutations in MSH3 have so far been associated with Lynch Syndrome, although it is known that impaired MSH3 activity leads to a partial defect in mismatch repair (MMR), with low levels of microsatellite instability at the loci with dinucleotide repeats in colorectal cancer (CRC), thus suggesting a role for MSH3 in carcinogenesis. To determine a possible role of MSH3 as predisposing to CRC in Lynch syndrome, we screened MSH3 for germ-line mutations in 79 unrelated Lynch patients who were negative for pathogenetic mutations in MLH1, MSH2 and MSH6. We found 13 mutant alleles, including silent, missense and intronic variants. These variants were identified through denaturing high performance liquid chromatography and subsequent DNA sequencing. In one Lynch family, the index case with early-onset colon cancer was a carrier of a polymorphism in the MSH2 gene and two variants in the MSH3 gene. These variants were associated with the disease in the family, thus suggesting the involvement of MSH3 in colon tumour progression. We hypothesise a model in which variants of the MSH3 gene behave as low-risk alleles that contribute to the risk of colon cancer in Lynch families, mostly with other low-risk alleles of MMR genes. Copyright © 2010 UICC.

Energy, ageing, fidelity and sex: oocyte mitochondrial DNA as a protected genetic template

PubMed Central

de Paula, Wilson B. M.; Lucas, Cathy H.; Agip, Ahmed-Noor A.; Vizcay-Barrena, Gema; Allen, John F.

2013-01-01

Oxidative phosphorylation couples ATP synthesis to respiratory electron transport. In eukaryotes, this coupling occurs in mitochondria, which carry DNA. Respiratory electron transport in the presence of molecular oxygen generates free radicals, reactive oxygen species (ROS), which are mutagenic. In animals, mutational damage to mitochondrial DNA therefore accumulates within the lifespan of the individual. Fertilization generally requires motility of one gamete, and motility requires ATP. It has been proposed that oxidative phosphorylation is nevertheless absent in the special case of quiescent, template mitochondria, that these remain sequestered in oocytes and female germ lines and that oocyte mitochondrial DNA is thus protected from damage, but evidence to support that view has hitherto been lacking. Here we show that female gametes of Aurelia aurita, the common jellyfish, do not transcribe mitochondrial DNA, lack electron transport, and produce no free radicals. In contrast, male gametes actively transcribe mitochondrial genes for respiratory chain components and produce ROS. Electron microscopy shows that this functional division of labour between sperm and egg is accompanied by contrasting mitochondrial morphology. We suggest that mitochondrial anisogamy underlies division of any animal species into two sexes with complementary roles in sexual reproduction. We predict that quiescent oocyte mitochondria contain DNA as an unexpressed template that avoids mutational accumulation by being transmitted through the female germ line. The active descendants of oocyte mitochondria perform oxidative phosphorylation in somatic cells and in male gametes of each new generation, and the mutations that they accumulated are not inherited. We propose that the avoidance of ROS-dependent mutation is the evolutionary pressure underlying maternal mitochondrial inheritance and the developmental origin of the female germ line. PMID:23754815

Spectrum of APC and MUTYH germ-line mutations in Russian patients with colorectal malignancies.

PubMed

Yanus, G A; Akhapkina, T A; Ivantsov, A O; Preobrazhenskaya, E V; Aleksakhina, S N; Bizin, I V; Sokolenko, A P; Mitiushkina, N V; Kuligina, E Sh; Suspitsin, E N; Venina, A R; Holmatov, M M; Zaitseva, O A; Yatsuk, O S; Pashkov, D V; Belyaev, A M; Togo, A V; Imyanitov, E N; Iyevleva, A G

2018-05-01

Distribution of cancer-predisposing mutations demonstrates significant interethnic variations. This study aimed to evaluate patterns of APC and MUTYH germ-line mutations in Russian patients with colorectal malignancies. APC gene defects were identified in 26/38 (68%) subjects with colon polyposis; 8/26 (31%) APC mutations were associated with 2 known mutational hotspots (p.E1309Dfs*4 [n = 5] and p.Q1062fs* [n = 3]), while 6/26 (23%) mutations were novel (p.K73Nfs*6, p.S254Hfs*12, p.S1072Kfs*9, p.E1547Kfs*11, p.L1564X and p.C1263Wfs*22). Biallelic mutations in MUTYH gene were detected in 3/12 (25%) remaining subjects with polyposis and in 6/90 (6.7%) patients with colorectal cancer (CRC) carrying KRAS p.G12C substitution, but not in 231 early-onset CRC cases negative for KRAS p.G12C allele. In addition to known European founder alleles p.Y179C and p.G396D, this study revealed a recurrent character of MUTYH p.R245H germ-line mutation. Besides that, 3 novel pathogenic MUTYH alleles (p.L111P, p.R245S and p.Q293X) were found. Targeted next-generation sequencing of 7 APC/MUTYH mutation-negative DNA samples identified novel potentially pathogenic POLD1 variant (p.L460R) in 1 patient and known low-penetrant cancer-associated allele CHEK2 p.I157T in 3 patients. The analysis of 1120 healthy subjects revealed 15 heterozygous carriers of recurrent MUTYH mutations, thus the expected incidence of MUTYH-associated polyposis in Russia is likely to be 1:23 000. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Stem cells, in vitro gametogenesis and male fertility.

PubMed

Nagamatsu, Go; Hayashi, Katsuhiko

2017-12-01

Reconstitution in culture of biological processes, such as differentiation and organization, is a key challenge in regenerative medicine, and one in which stem cell technology plays a central role. Pluripotent stem cells and spermatogonial stem cells are useful materials for reconstitution of germ cell development in vitro , as they are capable of differentiating into gametes. Reconstitution of germ cell development, termed in vitro gametogenesis, will provide an experimental platform for a better understanding of germ cell development, as well as an alternative source of gametes for reproduction, with the potential to cure infertility. Since germ cells are the cells for 'the next generation', both the culture system and its products must be carefully evaluated. In this issue, we summarize the progress in in vitro gametogenesis, most of which has been made using mouse models, as well as the future challenges in this field. © 2017 Society for Reproduction and Fertility.

Surfing the wave, cycle, life history, and genes/proteins expressed by testicular germ cells. Part 4: intercellular bridges, mitochondria, nuclear envelope, apoptosis, ubiquitination, membrane/voltage-gated channels, methylation/acetylation, and transcription factors.

PubMed

Hermo, Louis; Pelletier, R-Marc; Cyr, Daniel G; Smith, Charles E

2010-04-01

As germ cells divide and differentiate from spermatogonia to spermatozoa, they share a number of structural and functional features that are common to all generations of germ cells and these features are discussed herein. Germ cells are linked to one another by large intercellular bridges which serve to move molecules and even large organelles from the cytoplasm of one cell to another. Mitochondria take on different shapes and features and topographical arrangements to accommodate their specific needs during spermatogenesis. The nuclear envelope and pore complex also undergo extensive modifications concomitant with the development of germ cell generations. Apoptosis is an event that is normally triggered by germ cells and involves many proteins. It occurs to limit the germ cell pool and acts as a quality control mechanism. The ubiquitin pathway comprises enzymes that ubiquitinate as well as deubiquitinate target proteins and this pathway is present and functional in germ cells. Germ cells express many proteins involved in water balance and pH control as well as voltage-gated ion channel movement. In the nucleus, proteins undergo epigenetic modifications which include methylation, acetylation, and phosphorylation, with each of these modifications signaling changes in chromatin structure. Germ cells contain specialized transcription complexes that coordinate the differentiation program of spermatogenesis, and there are many male germ cell-specific differences in the components of this machinery. All of the above features of germ cells will be discussed along with the specific proteins/genes and abnormalities to fertility related to each topic. Copyright 2009 Wiley-Liss, Inc.

IGF1R signalling in testicular germ cell tumour cells impacts on cell survival and acquired cisplatin resistance.

PubMed

Selfe, Joanna; Goddard, Neil C; McIntyre, Alan; Taylor, Kathryn R; Renshaw, Jane; Popov, Sergey D; Thway, Khin; Summersgill, Brenda; Huddart, Robert A; Gilbert, Duncan C; Shipley, Janet M

2018-02-01

Testicular germ cell tumours (TGCTs) are the most frequent malignancy and cause of death from solid tumours in the 20- to 40-year age group. Although most cases show sensitivity to cis-platinum-based chemotherapy, this is associated with long-term toxicities and chemo-resistance. Roles for receptor tyrosine kinases other than KIT are largely unknown in TGCT. We therefore conducted a phosphoproteomic screen and identified the insulin growth factor receptor-1 (IGF1R) as both highly expressed and activated in TGCT cell lines representing the nonseminomatous subtype. IGF1R was also frequently expressed in tumour samples from patients with nonseminomas. Functional analysis of cell line models showed that long-term shRNA-mediated IGF1R silencing leads to apoptosis and complete ablation of nonseminoma cells with active IGF1R signalling. Cell lines with high levels of IGF1R activity also showed reduced AKT signalling in response to decreased IGF1R expression as well as sensitivity to the small-molecule IGF1R inhibitor NVP-AEW541. These results were in contrast to those in the seminoma cell line TCAM2 that lacked IGF1R signalling via AKT and was one of the two cell lines least sensitive to the IGF1R inhibitor. The dependence on IGF1R activity in the majority of nonseminomas parallels the known role of IGF signalling in the proliferation, migration, and survival of primordial germ cells, the putative cell of origin for TGCT. Upregulation of IGF1R expression and signalling was also found to contribute to acquired cisplatin resistance in an in vitro nonseminoma model, providing a rationale for targeting IGF1R in cisplatin-resistant disease. © 2017 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland. © 2017 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

The forkhead transcription factor FoxY regulates Nanos

PubMed Central

Song, Jia L.; Wessel, Gary M.

2012-01-01

FoxY is a member of the forkhead transcription factor family that appeared enriched in the presumptive germ line of sea urchins (Ransick et al., 2002, Dev Biol 246:132). Here we test the hypothesis that FoxY is involved in germ line determination in this animal. We found two splice forms of FoxY that share the same DNA-binding domain but vary in the carboxy-terminal trans-activation/repression domain. Both forms of the FoxY protein are present in the ovary and in the early embryo, and their mRNAs accumulate to their highest levels in the small micromeres and adjacent non-skeletogenic mesoderm. Knockdown of FoxY resulted in a dramatic decrease in the Nanos mRNA and protein levels as well as a loss of coelomic pouches in the 2-week-old larvae. Our results indicate that FoxY positively regulates Nanos at the transcriptional level and is essential for reproductive potential in this organism. PMID:22777754

The forkhead transcription factor FoxY regulates Nanos.

PubMed

Song, Jia L; Wessel, Gary M

2012-10-01

FoxY is a member of the forkhead transcription factor family that appeared enriched in the presumptive germ line of sea urchins (Ransick et al. Dev Biol 2002;246:132). Here, we test the hypothesis that FoxY is involved in germ line determination in this animal. We found two splice forms of FoxY that share the same DNA-binding domain, but vary in the carboxy-terminal trans-activation/repression domain. Both forms of the FoxY protein are present in the egg and in the early embryo, and their mRNAs accumulate to their highest levels in the small micromeres and adjacent non-skeletogenic mesoderm. Knockdown of FoxY resulted in a dramatic decrease in Nanos mRNA and protein levels as well as a loss of coelomic pouches in 2-week-old larvae. Our results indicate that FoxY positively regulates Nanos at the transcriptional level and is essential for reproductive potential in this organism. Copyright © 2012 Wiley Periodicals, Inc.

Day-night cycles and the sleep-promoting factor, Sleepless, affect stem cell activity in the Drosophila testis.

PubMed

Tulina, Natalia M; Chen, Wen-Feng; Chen, Jung Hsuan; Sowcik, Mallory; Sehgal, Amita

2014-02-25

Adult stem cells maintain tissue integrity and function by renewing cellular content of the organism through regulated mitotic divisions. Previous studies showed that stem cell activity is affected by local, systemic, and environmental cues. Here, we explore a role of environmental day-night cycles in modulating cell cycle progression in populations of adult stem cells. Using a classic stem cell system, the Drosophila spermatogonial stem cell niche, we reveal daily rhythms in division frequencies of germ-line and somatic stem cells that act cooperatively to produce male gametes. We also examine whether behavioral sleep-wake cycles, which are driven by the environmental day-night cycles, regulate stem cell function. We find that flies lacking the sleep-promoting factor Sleepless, which maintains normal sleep in Drosophila, have increased germ-line stem cell (GSC) division rates, and this effect is mediated, in part, through a GABAergic signaling pathway. We suggest that alterations in sleep can influence the daily dynamics of GSC divisions.

Germ-line engineering, freedom, and future generations.

PubMed

Cooke, Elizabeth F

2003-02-01

New technologies in germ-line engineering have raised many questions about obligations to future generations. In this article, I focus on the importance of increasing freedom and the equality of freedom for present and future generations, because these two ideals are necessary for a just society and because they are most threatened by the wide-scale privatisation of GLE technologies. However, there are ambiguities in applying these ideals to the issue of genetic technologies. I argue that Amartya Sen's capability theory can be used as a framework to ensure freedom and equality in the use of GLE technology. Capability theory articulates the goal of equalising real freedom by bringing all people up to a threshold of basic human capabilities. Sen's capability theory can clarify the proper moral goal of GLE insofar as this technology could be used to bring people up to certain basic human capabilities, thereby increasing their real freedom. And by increasing the freedom of those who lack basic human capabilities, GLE can aid in decreasing the inequalities of freedom among classes of people.

Cisplatin resistance induced in germ cell tumour cells is due to reduced susceptibility towards cell death but not to altered DNA damage induction or repair.

PubMed

Fenske, Annabelle E; Glaesener, Stephanie; Bokemeyer, Carsten; Thomale, Juergen; Dahm-Daphi, Jochen; Honecker, Friedemann; Dartsch, Dorothee C

2012-11-28

To identify factors involved in cisplatin (CDDP) resistance of germ cell tumours (GCTs), we exposed NTERA-2 cells, and the platinum-adapted subline NTERA-2R to CDDP and compared their response. While both cell lines showed comparable proliferation, NTERA-2R cells were clearly more resistant to the drug than the parental NTERA-2 cell line. Interestingly, the two lines showed identical extent of DNA adduct formation and elimination, indicating that neither changes in CDDP uptake, nor altered drug efflux, DNA binding, or repair caused the difference in resistance. Similarly, no difference occurred in the time-course of γH2AX formation, which was not linked to 53BP1 accumulation. In contrast, NTERA-2R cells showed a more pronounced dose-dependent S phase delay, a transient G(2)/M-block, and subsequent release into immediate cell death. We thus conclude that the enhanced resistance against CDDP is linked to reduced susceptibility to cell death rather than to an altered DNA adduct formation or adduct removal. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

ROCK inhibitor is not required for embryoid body formation from singularized human embryonic stem cells.

PubMed

Pettinato, Giuseppe; Vanden Berg-Foels, Wendy S; Zhang, Ning; Wen, Xuejun

2014-01-01

We report a technology to form human embryoid bodies (hEBs) from singularized human embryonic stem cells (hESCs) without the use of the p160 rho-associated coiled-coil kinase inhibitor (ROCKi) or centrifugation (spin). hEB formation was tested under four conditions: +ROCKi/+spin, +ROCKi/-spin, -ROCKi/+spin, and -ROCKi/-spin. Cell suspensions of BG01V/hOG and H9 hESC lines were pipetted into non-adherent hydrogel substrates containing defined microwell arrays. hEBs of consistent size and spherical geometry can be formed in each of the four conditions, including the -ROCKi/-spin condition. The hEBs formed under the -ROCKi/-spin condition differentiated to develop the three embryonic germ layers and tissues derived from each of the germ layers. This simplified hEB production technique offers homogeneity in hEB size and shape to support synchronous differentiation, elimination of the ROCKi xeno-factor and rate-limiting centrifugation treatment, and low-cost scalability, which will directly support automated, large-scale production of hEBs and hESC-derived cells needed for clinical, research, or therapeutic applications.

Cloning, characterization, and expression analysis of the DEAD-box family genes, Fc-vasa and Fc-PL10a, in Chinese shrimp ( Fenneropenaeus chinensis)

NASA Astrophysics Data System (ADS)

Zhou, Qianru; Shao, Mingyu; Qin, Zhenkui; Kyoung, Ho Kang; Zhang, Zhifeng

2010-01-01

RNA helicases of the DEAD-box and related families are involved in various cellular processes including DNA replication, DNA repair, and RNA processing. However, the function of DEAD-box proteins in aquaculture species is poorly understood at molecular level. We obtained the full-length cDNA sequences of two genes encoding helicase-related proteins, Fc-vasa and Fc-PL10a, from the testes of Chinese shrimp, Fenneropenaeus chinensis. The two predicted amino acid sequences contain all the conserved motifs characterized by the DEAD-box family and several RGG repeats in the N-terminal regions. Homology and phylogenetic analyses indicate that they belong to the vasa and PL10 subfamilies. The three-dimensional structures of the two proteins were predicted with a homology modeling approach. Both core proteins consist of two tandem RecA-like domains similar to those of the DEAD-box RNA helicase. Using reverse transcription-polymerase chain reaction (RT-PCR) and real-time PCR we found that Fc-vasa was expressed specifically in the adult gonads. Transcription decreased in the ovary but increased in the testis during gonadal development. Fc-PL10a expression was widely distributed in the tissues we examined. Using in situ hybridization, we demonstrated that the Fc-vasa transcript is localized to the cytoplasm of the spermatogonia and oocytes. Thus, our results suggest that Fc-vasa plays an important role in germ-line development, and has utility as a germ cell lineage marker which will help to generate new insight into the origin and differentiation of germ cells as well as the regulation of reproduction in F. chinensis.

A Theory of L 1-Dissipative Solvers for Scalar Conservation Laws with Discontinuous Flux

NASA Astrophysics Data System (ADS)

Andreianov, Boris; Karlsen, Kenneth Hvistendahl; Risebro, Nils Henrik

2011-07-01

We propose a general framework for the study of L 1 contractive semigroups of solutions to conservation laws with discontinuous flux: u_t + mathfrak{f}(x,u)_x=0, qquad mathfrak{f}(x,u)= left\\{begin{array}{ll} f^l(u),& x < 0,\\ f^r(u), & x > 0, right.quadquadquad (CL) where the fluxes f l , f r are mainly assumed to be continuous. Developing the ideas of a number of preceding works ( Baiti and Jenssen in J Differ Equ 140(1):161-185, 1997; Towers in SIAM J Numer Anal 38(2):681-698, 2000; Towers in SIAM J Numer Anal 39(4):1197-1218, 2001; Towers et al. in Skr K Nor Vidensk Selsk 3:1-49, 2003; Adimurthi et al. in J Math Kyoto University 43(1):27-70, 2003; Adimurthi et al. in J Hyperbolic Differ Equ 2(4):783-837, 2005; Audusse and Perthame in Proc Roy Soc Edinburgh A 135(2):253-265, 2005; Garavello et al. in Netw Heterog Media 2:159-179, 2007; Bürger et al. in SIAM J Numer Anal 47:1684-1712, 2009), we claim that the whole admissibility issue is reduced to the selection of a family of "elementary solutions", which are piecewise constant weak solutions of the form c(x)=c^l11_{left\\{{x < 0}right\\}}+c^r11_{left\\{{x > 0}right\\}}. We refer to such a family as a "germ". It is well known that (CL) admits many different L 1 contractive semigroups, some of which reflect different physical applications. We revisit a number of the existing admissibility (or entropy) conditions and identify the germs that underly these conditions. We devote specific attention to the "vanishing viscosity" germ, which is a way of expressing the "Γ-condition" of D iehl (J Hyperbolic Differ Equ 6(1):127-159, 2009). For any given germ, we formulate "germ-based" admissibility conditions in the form of a trace condition on the flux discontinuity line { x = 0} [in the spirit of V ol'pert (Math USSR Sbornik 2(2):225-267, 1967)] and in the form of a family of global entropy inequalities [following K ruzhkov (Math USSR Sbornik 10(2):217-243, 1970) and C arrillo (Arch Ration Mech Anal 147(4):269-361, 1999)]. We characterize those germs that lead to the L 1-contraction property for the associated admissible solutions. Our approach offers a streamlined and unifying perspective on many of the known entropy conditions, making it possible to recover earlier uniqueness results under weaker conditions than before, and to provide new results for other less studied problems. Several strategies for proving the existence of admissible solutions are discussed, and existence results are given for fluxes satisfying some additional conditions. These are based on convergence results either for the vanishing viscosity method (with standard viscosity or with specific viscosities "adapted" to the choice of a germ), or for specific germ-adapted finite volume schemes.

Posterior localization of ApVas1 positions the preformed germ plasm in the sexual oviparous pea aphid Acyrthosiphon pisum

PubMed Central

2014-01-01

Background Germline specification in some animals is driven by the maternally inherited germ plasm during early embryogenesis (inheritance mode), whereas in others it is induced by signals from neighboring cells in mid or late development (induction mode). In the Metazoa, the induction mode appears as a more prevalent and ancestral condition; the inheritance mode is therefore derived. However, regarding germline specification in organisms with asexual and sexual reproduction it has not been clear whether both strategies are used, one for each reproductive phase, or if just one strategy is used for both phases. Previously we have demonstrated that specification of germ cells in the asexual viviparous pea aphid depends on a preformed germ plasm. In this study, we extended this work to investigate how germ cells were specified in the sexual oviparous embryos, aiming to understand whether or not developmental plasticity of germline specification exists in the pea aphid. Results We employed Apvas1, a Drosophila vasa ortholog in the pea aphid, as a germline marker to examine whether germ plasm is preformed during oviparous development, as has already been seen in the viviparous embryos. During oogenesis, Apvas1 mRNA and ApVas1 protein were both evenly distributed. After fertilization, uniform expression of Apvas1 remained in the egg but posterior localization of ApVas1 occurred from the fifth nuclear cycle onward. Posterior co-localization of Apvas1/ApVas1 was first identified in the syncytial blastoderm undergoing cellularization, and later we could detect specific expression of Apvas1/ApVas1 in the morphologically identifiable germ cells of mature embryos. This suggests that Apvas1/ApVas1-positive cells are primordial germ cells and posterior localization of ApVas1 prior to cellularization positions the preformed germ plasm. Conclusions We conclude that both asexual and sexual pea aphids rely on the preformed germ plasm to specify germ cells and that developmental plasticity of germline specification, unlike axis patterning, occurs in neither of the two aphid reproductive phases. Consequently, the maternal inheritance mode implicated by a preformed germ plasm in the oviparous pea aphid becomes a non-canonical case in the Hemimetabola, where so far the zygotic induction mode prevails in most other studied insects. PMID:24855557

Collective cell migration in development

PubMed Central

Scarpa, Elena

2016-01-01

During embryonic development, tissues undergo major rearrangements that lead to germ layer positioning, patterning, and organ morphogenesis. Often these morphogenetic movements are accomplished by the coordinated and cooperative migration of the constituent cells, referred to as collective cell migration. The molecular and biomechanical mechanisms underlying collective migration of developing tissues have been investigated in a variety of models, including border cell migration, tracheal branching, blood vessel sprouting, and the migration of the lateral line primordium, neural crest cells, or head mesendoderm. Here we review recent advances in understanding collective migration in these developmental models, focusing on the interaction between cells and guidance cues presented by the microenvironment and on the role of cell–cell adhesion in mechanical and behavioral coupling of cells within the collective. PMID:26783298

Black carp vasa identifies embryonic and gonadal germ cells.

PubMed

Xue, Ting; Yu, Miao; Pan, Qihua; Wang, Yizhou; Fang, Jian; Li, Lingyu; Deng, Yu; Chen, Kai; Wang, Qian; Chen, Tiansheng

2017-07-01

Identification of molecular markers is an essential step in the study of germ cells. Vasa is an RNA helicase and a well-known germ cell marker that plays a crucial role in germ cell development. Here, we identified the Vasa homolog termed Mpvasa as the first germ cell marker in black carp (Mylopharyngodon piceus). First, a 2819-bp full-length Mpvasa complementary DNA (cDNA) was cloned by PCR using degenerated primers of conserved sequences and gene-specific primers. The Mpvasa cDNA sequence encodes a 637-amino acid protein that contains eight conserved characteristic motifs of the DEAD box protein family, and shares high identity to grass carp (81%) and zebrafish (74%) vasa homologs. Second, Mpvasa expression was restricted to the gonad in adulthood by RT-PCR and Western blot analysis. The dynamic patterns of temporal-spatial expression of Mpvasa during gametogenesis were examined by in situ hybridization, and Mpvasa transcripts were strictly detected in gonadal germ cells throughout oogenesis, predominantly in immature oocytes (stage I, II, and III oocytes). Third, Mpvasa transcripts were highly detected in unfertilized eggs and early embryos, and the signal indicated a dynamic migration of the primordial germ cells during embryogenesis, suggesting that Mpvasa transcripts were maternally inherited and specifically distributed in germ cells. Taken together, these results demonstrated that Mpvasa is an applicable molecular marker for identification of gonadal and embryonic germ cells, which facilitates the isolation and utilization of germ cells in black carp.

Intratubular germ cell neoplasia of the human testis: heterogeneous protein expression and relation to invasive potential

PubMed Central

Mitchell, Rod T; Camacho-Moll, Maria; Macdonald, Joni; Anderson, Richard A; Kelnar, Christopher JH; O’Donnell, Marie; Sharpe, Richard M; Smith, Lee B; Grigor, Ken M; Wallace, W Hamish B; Stoop, Hans; Wolffenbuttel, Katja P; Donat, Roland

2014-01-01

Testicular germ cell cancer develops from pre-malignant intratubular germ cell neoplasia, unclassified cells that are believed to arise from failure of normal maturation of fetal germ cells from gonocytes (OCT4+/ MAGEA4−) into pre-spermatogonia (OCT4−/MAGEA4+). Intratubular germ cell neoplasia cell subpopulations based on stage of germ cell differentiation have been described, however the importance of these subpopulations in terms of invasive potential has not been reported. We hypothesised that cells expressing an immature (OCT4+/MAGEA4−) germ cell profile would exhibit an increased proliferation rate compared to those with a mature profile (OCT4+/ MAGEA4+). Therefore, we performed triple immunofluorescence and stereology to quantify the different intratubular germ cell neoplasia cell subpopulations, based on expression of germ cell (OCT4, PLAP, AP2γ, MAGEA4, VASA) and proliferation (Ki67) markers, in testis sections from patients with pre-invasive disease, seminoma and non-seminoma. We compared these subpopulations with normal human fetal testis and with seminoma cells. Heterogeneity of protein expression was demonstrated in intratubular germ cell neoplasia cells with respect to gonocyte and spermatogonial markers. It included an embryonic/fetal germ cell subpopulation lacking expression of the definitive intratubular germ cell neoplasia marker OCT4, that did not correspond to a physiological (fetal) germ cell subpopulation. OCT4+/MAGEA4- cells showed a significantly increased rate of proliferation compared with the OCT4+/MAGEA4+ population (12.8 v 3.4%, p<0.0001) irrespective of histological tumour type, reflected in the predominance of OCT4+/MAGEA4− cells in the invasive tumour component. Surprisingly, OCT4+/MAGEA4− cells in patients with pre-invasive disease showed significantly higher proliferation compared to those with seminoma or non-seminoma (18.1 v 10.2 v 7.2%, p<0.05 respectively). In conclusion, this study has demonstrated that OCT4+/MAGEA4− cells are the most frequent and most proliferative cell population in tubules containing intratubular germ cell neoplasia, which appears to be an important factor in determining invasive potential of intratubular germ cell neoplasia to seminomas. PMID:24457464

Walls around tumours - why plants do not develop cancer.

PubMed

Doonan, John H; Sablowski, Robert

2010-11-01

In plants, as in animals, most cells that constitute the organism limit their reproductive potential in order to provide collective support for the immortal germ line. And, as in animals, the mechanisms that restrict the proliferation of somatic cells in plants can fail, leading to tumours. There are intriguing similarities in tumorigenesis between plants and animals, including the involvement of the retinoblastoma pathway as well as overlap with mechanisms that are used for stem cell maintenance. However, plant tumours are less frequent and are not as lethal as those in animals. We argue that fundamental differences between plant and animal development make it much more difficult for individual plant cells to escape communal controls.

[Programmed mouse genome modifications].

PubMed

Babinet, C

1998-02-01

The availability, in the mouse, of embryonic stem cells (ES cells) which have the ability to colonize the germ line of a developing embryo, has opened entirely new avenues to the genetic approach of embryonic development, physiology and pathology of this animal. Indeed, it is now possible, using homologous recombination in ES cells, to introduce mutations in any gene as long as it has been cloned. Thus, null as well as more subtle mutations can be created. Furthermore, scenarios are currently being derived which will allow one to generate conditional mutations. Taken together, these methods offer a tremendous tool to study gene function in vivo; they also open the way to creating murine models of human genetic diseases.

Temporal germ cell development strategy during continuous spermatogenesis within the montane lizard, Sceloporus bicanthalis (Squamata; Phrynosomatidae).

PubMed

Gribbins, Kevin; Anzalone, Marla; Collier, Matthew; Granados-González, Gisela; Villagrán-Santa Cruz, Maricela; Hernández-Gallegos, Oswaldo

2011-10-01

Sceloporus bicanthalis is a viviparous lizard that lives at higher elevations in Mexico. Adult male S. bicanthalis were collected (n = 36) from the Nevado de Toluca, Mexico (elevation is 4200 m) during August to December, 2007 and January to July, 2008. Testes were extracted, fixed in Trumps, and dehydrated in a graded series of ethanol. Tissues were embedded, sectioned (2 μm), stained, and examined via a light microscope to determine the spermatogenic developmental strategy of S. bicanthalis. In all months examined, the testes were spermiogenically active; based on this, plus the presence of sperm in the lumina of seminiferous tubules, we inferred that S. bicanthalis had year-round or continuous spermatogenesis, unlike most reptiles that occupy a temperate or montane habitat. It was recently reported that seasonally breeding reptiles had a temporal germ cell development strategy similar to amphibians, where germ cells progress through spermatogenesis as a single population, which leads to a single spermiation event. This was much different than spatial development within the testis of other derived amniotes. We hypothesized that germ cell development was temporal in S. bicanthalis. Therefore, we wanted to determine whether reptiles that practice continuous spermatogenesis have a mammalian-like spatial germ cell development, which is different than the typical temperate reptile exhibiting a temporal development. In the present study, S. bicanthalis had a temporal development strategy, despite its continuous spermatogenic cycle, making them similar to tropical anoles. Copyright © 2011 Elsevier Inc. All rights reserved.

Stem Cell Information: Glossary

MedlinePlus

... germ cells (those that would become sperm and eggs). Embryonic germ cells are thought to have properties ... the male gamete (sperm) and the female gamete (egg). Fetus - In humans, the developing human from approximately ...

Measured Results

ERIC Educational Resources Information Center

Wiley, Frank N.

2009-01-01

Teachers have the "germiest" jobs in America. Only one professional can do anything about getting rid of germs once they have infected buildings: the school custodian. Custodians should be the first line of defense against pathogens in schools. Unfortunately, most are not trained or equipped to deal with this invisible world. Facility maintenance…

Germ cell specification and ovary structure in the rotifer Brachionus plicatilis

PubMed Central

2010-01-01

Background The segregation of the germline from somatic tissues is an essential process in the development of all animals. Specification of the primordial germ cells (PGCs) takes place via different strategies across animal phyla; either specified early in embryogenesis by the inheritance of maternal determinants in the cytoplasm of the oocyte ('preformation') or selected later in embryonic development from undifferentiated precursors by a localized inductive signal ('epigenesis'). Here we investigate the specification and development of the germ cells in the rotifer Brachionus plicatilis, a member of the poorly-characterized superphyla Lophotrochozoa, by isolating the Brachionus homologues of the conserved germ cell markers vasa and nanos, and examining their expression using in situ hybridization. Results Bpvasa and Bpnos RNA expression have very similar distributions in the Brachionus ovary, showing ubiquitous expression in the vitellarium, with higher levels in the putative germ cell cluster. Bpvas RNA expression is present in freshly laid eggs, remaining ubiquitous in embryos until at least the 96 cell stage after which expression narrows to a small cluster of cells at the putative posterior of the embryo, consistent with the developing ovary. Bpnos RNA expression is also present in just-laid eggs but expression is much reduced by the four-cell stage and absent by the 16-cell stage. Shortly before hatching of the juvenile rotifer from the egg, Bpnos RNA expression is re-activated, located in a subset of posterior cells similar to those expressing Bpvas at the same stage. Conclusions The observed expression of vasa and nanos in the developing B. plicatilis embryo implies an epigenetic origin of primordial germ cells in Rotifer. PMID:20849649

Comparative analysis of miRNA expression during the development of insects of different metamorphosis modes and germ-band types.

PubMed

Ylla, Guillem; Piulachs, Maria-Dolors; Belles, Xavier

2017-10-11

Do miRNAs contribute to specify the germ-band type and the body structure in the insect embryo? Our goal was to address that issue by studying the changes in miRNA expression along the ontogeny of the German cockroach Blattella germanica, which is a short germ-band and hemimetabolan species. We sequenced small RNA libraries representing 11 developmental stages of B. germanica ontogeny (with especial emphasis on embryogenesis) and the changes in miRNA expression were examined. Data were compared with equivalent data for two long germ-band holometabolan species Drosophila melanogaster and Drosophila virilis, and the short germ-band holometabolan species Tribolium castaneum. The identification of B. germanica embryo small RNA sequences unveiled miRNAs not detected in previous studies, such as those of the MIR-309 family and 54 novel miRNAs. Four main waves of miRNA expression were recognized (with most miRNA changes occurring during the embryonic stages): the first from day 0 to day 1 of embryogenesis, the second during mid-embryogenesis (days 0-6), the third (with an acute expression peak) on day 2 of embryonic development, and the fourth during post-embryonic development. The second wave defined the boundaries of maternal-to-zygotic transition, with maternal mRNAs being cleared, presumably by Mir-309 and associated scavenger miRNAs. miRNAs follow well-defined patterns of expression over hemimetabolan ontogeny, patterns that are more diverse during embryonic development than during the nymphal stages. The results suggest that miRNAs play important roles in the developmental transitions between the embryonic stages of development (starting with maternal loading), during which they might influence the germ-band type and metamorphosis mode.

Cross-talk between miR-471-5p and autophagy component proteins regulates LC3-associated phagocytosis (LAP) of apoptotic germ cells.

PubMed

Panneerdoss, Subbarayalu; Viswanadhapalli, Suryavathi; Abdelfattah, Nourhan; Onyeagucha, Benjamin C; Timilsina, Santosh; Mohammad, Tabrez A; Chen, Yidong; Drake, Michael; Vuori, Kristiina; Kumar, T Rajendra; Rao, Manjeet K

2017-09-19

Phagocytic clearance of apoptotic germ cells by Sertoli cells is vital for germ cell development and differentiation. Here, using a tissue-specific miRNA transgenic mouse model, we show that interaction between miR-471-5p and autophagy member proteins regulates clearance of apoptotic germ cells via LC3-associated phagocytosis (LAP). Transgenic mice expressing miR-471-5p in Sertoli cells show increased germ cell apoptosis and compromised male fertility. Those effects are due to defective engulfment and impaired LAP-mediated clearance of apoptotic germ cells as miR-471-5p transgenic mice show lower levels of Dock180, LC3, Atg12, Becn1, Rab5 and Rubicon in Sertoli cells. Our results reveal that Dock180 interacts with autophagy member proteins to constitute a functional LC3-dependent phagocytic complex. We find that androgen regulates Sertoli cell phagocytosis by controlling expression of miR-471-5p and its target proteins. These findings suggest that recruitment of autophagy machinery is essential for efficient clearance of apoptotic germ cells by Sertoli cells using LAP.Although phagocytic clearance of apoptotic germ cells by Sertoli cells is essential for spermatogenesis, little of the mechanism is known. Here the authors show that Sertoli cells employ LC3-associated phagocytosis (LAP) by recruiting autophagy member proteins to clear apoptotic germ cells.

Sex determination in mammalian germ cells

PubMed Central

Spiller, Cassy M; Bowles, Josephine

2015-01-01

Germ cells are the precursors of the sperm and oocytes and hence are critical for survival of the species. In mammals, they are specified during fetal life, migrate to the developing gonads and then undergo a critical period during which they are instructed, by the soma, to adopt the appropriate sexual fate. In a fetal ovary, germ cells enter meiosis and commit to oogenesis, whereas in a fetal testis, they avoid entry into meiosis and instead undergo mitotic arrest and mature toward spermatogenesis. Here, we discuss what we know so far about the regulation of sex-specific differentiation of germ cells, considering extrinsic molecular cues produced by somatic cells, as well as critical intrinsic changes within the germ cells. This review focuses almost exclusively on our understanding of these events in the mouse model. PMID:25791730

Germ cell pluripotency, premature differentiation and susceptibility to testicular teratomas in mice

PubMed Central

Heaney, Jason D.; Anderson, Ericka L.; Michelson, Megan V.; Zechel, Jennifer L.; Conrad, Patricia A.; Page, David C.; Nadeau, Joseph H.

2012-01-01

Testicular teratomas result from anomalies in germ cell development during embryogenesis. In the 129 family of inbred strains of mice, teratomas initiate around embryonic day (E) 13.5 during the same developmental period in which female germ cells initiate meiosis and male germ cells enter mitotic arrest. Here, we report that three germ cell developmental abnormalities, namely continued proliferation, retention of pluripotency, and premature induction of differentiation, associate with teratoma susceptibility. Using mouse strains with low versus high teratoma incidence (129 versus 129-Chr19MOLF/Ei), and resistant to teratoma formation (FVB), we found that germ cell proliferation and expression of the pluripotency factor Nanog at a specific time point, E15.5, were directly related with increased tumor risk. Additionally, we discovered that genes expressed in pre-meiotic embryonic female and adult male germ cells, including cyclin D1 (Ccnd1) and stimulated by retinoic acid 8 (Stra8), were prematurely expressed in teratoma-susceptible germ cells and, in rare instances, induced entry into meiosis. As with Nanog, expression of differentiation-associated factors at a specific time point, E15.5, increased with tumor risk. Furthermore, Nanog and Ccnd1, genes with known roles in testicular cancer risk and tumorigenesis, respectively, were co-expressed in teratoma-susceptible germ cells and tumor stem cells, suggesting that retention of pluripotency and premature germ cell differentiation both contribute to tumorigenesis. Importantly, Stra8-deficient mice had an 88% decrease in teratoma incidence, providing direct evidence that premature initiation of the meiotic program contributes to tumorigenesis. These results show that deregulation of the mitotic-meiotic switch in XY germ cells contributes to teratoma initiation. PMID:22438569

Germ tube and chlamydospore formation by Candida albicans on a new medium.

PubMed

Beheshti, F; Smith, A G; Krause, G W

1975-10-01

A new medium composed of "cream of rice" infusion, oxgall, Tween 80, and agar is described for the sequential development of germ tubes and chlamydospores by Candida albicans. The procedure used (Dalmau's technique) is an improvement over the fluid substrate procedures previously advocated for germ tube formation. That the same preparation is then used for chlamydospore production is of practical importance for the clinical mycology laboratory.

Topology of the germ plasm and development of primordial germ cells in inverted amphibian eggs

NASA Technical Reports Server (NTRS)

Wakahara, M.; Neff, A. W.; Malacinski, G. M.

1984-01-01

Inverted Xenopus eggs have reduced numbers of primordial germ cells (PGCs). The extent of the reduction varies from spawning to spawning. Histologic examination revealed that PGC counts were lowest in inverted eggs which displayed the greatest amount of shift in the vegetal mass of large yolk platelets, although the germ plasm itself always remained localized in the egg's original vegetal hemisphere. Even at blastulation the germ plasm continued to be localized in the egg's original vegetal hemisphere. In many cases, however, it was confined to the periphery of the embryo, which probably accounts for the reduced PGC number in some tadpoles. In other cases it may have been dispersed and therefore not detectable in histologic analyses. Although the altered site of involution in inverted embryos did not influence PGC development, subsequent cell movement patterns apparently did. Those embryos which displayed the largest degree of pattern reversal at the tail-bud stage also exhibited the most extreme reduction in PGC numbers. A brief cold shock (4 degrees C, 10 min) prior to first cleavage leads to a further reduction in PGC numbers in inverted embryos, probably as a result of the displacement of the germ plasm away from its original vegetal pole location.

Expression of the oncoprotein gankyrin and phosphorylated retinoblastoma protein in human testis and testicular germ cell tumor.

PubMed

Ando, Satoshi; Matsuoka, Taeko; Kawai, Koji; Sugita, Shintaro; Joraku, Akira; Kojima, Takahiro; Suetomi, Takahiro; Miyazaki, Jun; Fujita, Jun; Nishiyama, Hiroyuki

2014-10-01

The oncoprotein, gankyrin, is known to facilitate cell proliferation through phosphorylation and degradation of retinoblastoma protein. In the present study, we evaluated the expression of gankyrin and phosphorylated retinoblastoma protein in human testis and testicular germ cell tumors. The effects of suppression of gankyrin by locked nucleic acid on phosphorylation status of retinoblastoma and cell proliferation were analyzed using western blot analysis and testicular tumor cell line NEC8. The expressions of gankyrin, retinoblastoma and retinoblastoma protein were analyzed in 93 testicular germ cell tumor samples and five normal human testis by immunohistochemistry. The retinoblastoma protein expression was determined using an antibody to retinoblastoma protein, Ser795. Gankyrin was expressed in NEC8 cells as well as a normal human testis and testicular tumors. Suppression of gankyrin by locked nucleic acid led to suppression of retinoblastoma protein and cell proliferation in NEC8 cells. Immunohistochemistry of normal testis showed that gankyrin is expressed dominantly in spermatocytes. In testicular germ cell tumors, high expressions of gankyrin and phosphorylated-retinoblastoma protein were observed in seminoma and embryonal carcinoma, whereas the expressions of both proteins were weak in histological subtypes of non-seminoma. Growing teratoma and testicular malignant transformation tissues expressed phosphorylated-retinoblastoma protein strongly, but gankyrin faintly. Gankyrin is dominantly expressed in normal spermatocytes and seminoma/embryonal carcinoma, and its expression correlates well with retinoblastoma protein expression except in the growing teratoma and testicular malignant transformation cases. These data provide new insights into the molecular mechanisms of normal spermatogenesis and pathogenesis of testicular germ cell tumors. © 2014 The Japanese Urological Association.

Expression of germline markers in three species of amphioxus supports a preformation mechanism of germ cell development in cephalochordates

PubMed Central

2013-01-01

Background In a previous study, we showed that the cephalochordate amphioxus Branchiostoma floridae has localized maternal transcripts of conserved germ cell markers Vasa and Nanos in its early embryos. These results provided strong evidence to support a preformation mechanism for primordial germ cell (PGC) development in B. floridae. Results In this study, we further characterize the expression of B. floridae homologs of Piwi and Tudor, which play important roles in germline development in diverse metazoan animals. We show that maternal mRNA of one of the identified Piwi-like homologs, Bf-Piwil1, also colocalizes with Vasa in the vegetal germ plasm and has zygotic expression in both the putative PGCs and the tail bud, suggesting it may function in both germline and somatic stem cells. More interestingly, one Tudor family gene, Bf-Tdrd7, is only expressed maternally and colocalizes with Vasa in germ plasm, suggesting that it may function exclusively in germ cell specification. To evaluate the conservation of the preformation mechanism among amphioxus species, we further analyze Vasa, Nanos, Piwil1, and Tdrd7 expression in two Asian amphioxus species, B. belcheri and B. japonicum. Their maternal transcripts all localize in similar patterns to those seen in B. floridae. In addition, we labeled putative PGCs with Vasa antibody to trace their dynamic distribution in developing larvae. Conclusions We identify additional germ plasm components in amphioxus and demonstrate the molecular distinction between the putative germline stem cells and somatic stem cells. Moreover, our results suggest that preformation may be a conserved mechanism for PGC specification among Branchiostoma species. Our Vasa antibody staining results suggest that after the late neurula stage, amphioxus PGCs probably proliferate with the tail bud cells during posterior elongation and are deposited near the forming myomere boundaries. Subsequently, these PGCs would concentrate at the ventral tip of the myoseptal walls to form the gonad anlagen. PMID:23777831

Testicular histology and germ cell cytology during spermatogenesis in the Mississippi map turtle, Graptemys pseudogeographica kohnii, from Northeast Arkansas.

PubMed

Lancaster, Kelsey; Trauth, Stanley E; Gribbins, Kevin M

2014-01-01

The testicular histology and cytology of spermatogenesis in Graptemys pseudogeographica kohnii were examined using specimens collected between July 1996 and May 2004 from counties in northeastern Arkansas. A histological examination of the testes and germ cell cytology indicates a postnuptial testicular cycle of spermatogenesis and a major fall spermiation event. The majority of the germ cell populations in May and June specimens are represented by resting spermatogonia, type A spermatogonia, type B spermatogonia, pre-leptotene spermatocytes, and numerous Sertoli cell nuclei near the basement membrane. The start of proliferation is evident as spermatogonia in metaphase are present near the basal lamina and many of these germ cells have entered meiosis in June seminiferous tubules. Major spermatogenic events occur in the June and July specimens and result in an increased height of the seminiferous epithelium and increased diameter of the seminiferous tubules. The germ cell population during this time is represented by spermatogonia (type A, B, and resting), hypertrophic cells, large populations of early primary spermatocytes, and early round spermatids. By September, the major germ cell population has progressed past meiosis with abundant round and early elongating spermatids dominating the seminiferous epithelium. October seminiferous epithelia are marked by a decreas in height and mature spermatozoa fill the luminal space. Round and elongating spermatids constitute the largest portion of the germ cell population. Following the spermiation event, the testes enter a period of quiescence that lasts till the next spermatogenic cycle, which begins in the subsequent spring. Based on the cytological development of the seminiferous tubules revealed by our study, Graptemys pseudogeographica kohnii demonstrates a temporal germ cell development strategy similar to other temperate reptiles. A single major generation of germ cells progresses through spermatogenesis each year resulting in a single spermiation event with sperm stored within the epididymis until the next spring mating season.

Testicular histology and germ cell cytology during spermatogenesis in the Mississippi map turtle, Graptemys pseudogeographica kohnii, from Northeast Arkansas

PubMed Central

Lancaster, Kelsey; Trauth, Stanley E; Gribbins, Kevin M

2014-01-01

The testicular histology and cytology of spermatogenesis in Graptemys pseudogeographica kohnii were examined using specimens collected between July 1996 and May 2004 from counties in northeastern Arkansas. A histological examination of the testes and germ cell cytology indicates a postnuptial testicular cycle of spermatogenesis and a major fall spermiation event. The majority of the germ cell populations in May and June specimens are represented by resting spermatogonia, type A spermatogonia, type B spermatogonia, pre-leptotene spermatocytes, and numerous Sertoli cell nuclei near the basement membrane. The start of proliferation is evident as spermatogonia in metaphase are present near the basal lamina and many of these germ cells have entered meiosis in June seminiferous tubules. Major spermatogenic events occur in the June and July specimens and result in an increased height of the seminiferous epithelium and increased diameter of the seminiferous tubules. The germ cell population during this time is represented by spermatogonia (type A, B, and resting), hypertrophic cells, large populations of early primary spermatocytes, and early round spermatids. By September, the major germ cell population has progressed past meiosis with abundant round and early elongating spermatids dominating the seminiferous epithelium. October seminiferous epithelia are marked by a decreas in height and mature spermatozoa fill the luminal space. Round and elongating spermatids constitute the largest portion of the germ cell population. Following the spermiation event, the testes enter a period of quiescence that lasts till the next spermatogenic cycle, which begins in the subsequent spring. Based on the cytological development of the seminiferous tubules revealed by our study, Graptemys pseudogeographica kohnii demonstrates a temporal germ cell development strategy similar to other temperate reptiles. A single major generation of germ cells progresses through spermatogenesis each year resulting in a single spermiation event with sperm stored within the epididymis until the next spring mating season. PMID:26413408

Incorporation of in vitro digestive enzymes in an intestinal epithelial cell line model for protein hazard identification.

PubMed

Markell, Lauren K; Wezalis, Stephanie M; Roper, Jason M; Zimmermann, Cindi; Delaney, Bryan

2017-10-01

Relatively few proteins in nature produce adverse effects following oral exposure. Of those that do, effects are often observed in the gut, particularly on intestinal epithelial cells (IEC). Previous studies reported that addition of protein toxins to IEC lines disrupted monolayer integrity but innocuous dietary proteins did not. Studies presented here investigated the effects of innocuous (bovine serum albumin, β-lactoglobulin, RuBisCO, fibronectin) or hazardous (phytohaemagglutinin-E, concanavalin A, wheat germ agglutinin, melittin) proteins that either were untreated or exposed to digestive enzymes prior to addition to Caco-2 human IEC line monolayers. At high concentrations intact fibronectin caused an increase in monolayer permeability but other innocuous proteins did not whether exposed to digestive enzymes or not. In contrast, all untreated hazardous proteins and those that were resistant to digestion (ex. wheat germ agglutinin) disrupted monolayer integrity. However, proteins sensitive to degradation by digestive enzymes (ex. melittin) did not adversely affect monolayers when exposed to these enzymes prior to addition to IEC line monolayers. These results indicate that in vitro exposure of proteins to digestive enzymes can assist in differentiating between innocuous and hazardous proteins as another component to consider in the overall weight of evidence approach in protein hazard assessment. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Surgical outcomes in patients with primary mediastinal non-seminomatous germ cell tumours and elevated post-chemotherapy serum tumour markers.

PubMed

De Latour, Bertrand; Fadel, Elie; Mercier, Olaf; Mussot, Sacha; Fabre, Dominique; Fizazi, Karim; Dartevelle, Philippe

2012-07-01

Platinum-based chemotherapy followed by surgical resection of residual masses has become the standard treatment of patients with primary mediastinal non-seminomatous germ cell tumours (NSGCTs). Persistent serum tumour marker (STM) elevation after chemotherapy usually indicates a poor prognosis. We retrospectively assessed surgical outcomes in patients with high STM levels after chemotherapy for primary mediastinal NSGCT. Between 1983 and 2010, residual tumour excision was performed in 21 patients, 20 men and one woman with a median age of 30 years (range: 19-49 years), with primary mediastinal NSGCTs and high STM levels after platinum-based chemotherapy, followed by second-line chemotherapy in 11 patients. Alpha-fetoprotein was elevated in all 21 patients and β-human chorionic gonadotropin in three patients. Permanent histology demonstrated viable germ cell tumour (n=13), teratoma (n=3) or necrosis (n=5). After surgery, the STM levels returned to normal in 11 patients. Eight patients are alive with a median follow-up of 98 months. The 5-year survival rate was 36% and was not significantly affected by the use of preoperative second-line chemotherapy. At univariate analysis, only postoperative STM elevation and residual viable tumour, indicating incomplete resection, were significantly associated with lower survival (P=0.018 and P=0.04, respectively). In patients with primary mediastinal NSGCTs and elevated post-chemotherapy STMs, surgery is warranted when complete resection is deemed feasible. In specialized oncology centres, this aggressive approach can provide a cure in some patients.

Identification of Genes Uniquely Expressed in the Germ-Line Tissues of the Jewel Wasp Nasonia vitripennis

PubMed Central

Ferree, Patrick M.; Fang, Christopher; Mastrodimos, Mariah; Hay, Bruce A.; Amrhein, Henry; Akbari, Omar S.

2015-01-01

The jewel wasp Nasonia vitripennis is a rising model organism for the study of haplo-diploid reproduction characteristic of hymenopteran insects, which include all wasps, bees, and ants. We performed transcriptional profiling of the ovary, the female soma, and the male soma of N. vitripennis to complement a previously existing transcriptome of the wasp testis. These data were deposited into an open-access genome browser for visualization of transcripts relative to their gene models. We used these data to identify the assemblies of genes uniquely expressed in the germ-line tissues. We found that 156 protein-coding genes are expressed exclusively in the wasp testis compared with only 22 in the ovary. Of the testis-specific genes, eight are candidates for male-specific DNA packaging proteins known as protamines. We found very similar expression patterns of centrosome associated genes in the testis and ovary, arguing that de novo centrosome formation, a key process for development of unfertilized eggs into males, likely does not rely on large-scale transcriptional differences between these tissues. In contrast, a number of meiosis-related genes show a bias toward testis-specific expression, despite the lack of true meiosis in N. vitripennis males. These patterns may reflect an unexpected complexity of male gamete production in the haploid males of this organism. Broadly, these data add to the growing number of genomic and genetic tools available in N. vitripennis for addressing important biological questions in this rising insect model organism. PMID:26464360

Disruption of gap junctional intercellular communication by antibiotic gentamicin is associated with aberrant localization of occludin, N-cadherin, connexin 43, and vimentin in SerW3 Sertoli cells in vitro.

PubMed

Bekheet, Souad H M; Stahlmann, Ralf

2009-09-01

Spermatogenesis is a very complex process by which male germ cells differentiate into mature spermatozoa. The sophisticated communication network that controls spermatogenesis can be derailed so that dysfunction of one cell type propagates to all types as a cascade. This accounts for the particular vulnerability of the testis to environmental factors such as drugs and xenobiotics. Sertoli cells play an important role in protecting developing germ cells by forming a physiological barrier, limiting exposure to potentially toxic substrates, or conversely, facilitating uptake of xenobiotics within the testis. In this study, cells from the rat Sertoli line (SerW3) were incubated for 3, 6 and 9 subsequent days in serum free DMEM (SFDM) composed of DMEM supplemented with three different concentrations of antibiotic gentamicin (10, 30, and 100 μg). The effect of the three different concentrations of this antibiotic was determined on Sertoli cell-cell interaction through impaired expression of their constitutive tight junction proteins as early targets for different toxicants in vitro by immunochemistry analysis. The Sertoli SerW3 cell line illustrated the cytotoxicity of GS, as the intercellular junction proteins such as occludin, N-cadherin, connexin 43, and vimentin were delocalized from the membrane to the cytoplasmic compartment during exposure to the antibiotic. This study underlines the potential deleterious effects of the routine use of antibiotics during continuous cell culture.

Evolution of Human Rights in the Age of Biotechnology.

ERIC Educational Resources Information Center

Hron, Benjamin

1998-01-01

Considers how biotechnology affects human-rights issues; in particular, the need for reexamining concerns about reproductive technology, the rights of indigenous peoples, and the rights of future generations. Maintains that the new areas for human-rights discussions, such as germ-line manipulation and genetic screening, are unprecedented concerns…

Lamarck Will Not Lie Down.

ERIC Educational Resources Information Center

Lewin, Roger

1981-01-01

Describes recent research by Edward Steele appearing to support the Lamarckian theory of inheritance. Steele suggests that a mutant somatic cell favored by the environment will undergo clonal expansion. Altered genetic materials from these cells is then picked up by C-type viruses and inserted into the germ line genome. (CS)

Half a Tithe for Ethics.

ERIC Educational Resources Information Center

Larson, Edward J.

1993-01-01

Two ethical concerns about the Human Genome Project, which aims to sequence all the DNA of a human cell, are discussed: (1) use of germ-line gene therapy to treat perceived hereditary defects or enhance supposed genetic attributes, and (2) personal privacy and potential discrimination arising from possession of individual genetic information. (MSE)

Genome Wide DNA Methylation Profiles Provide Clues to the Origin and Pathogenesis of Germ Cell Tumors

PubMed Central

Rijlaarsdam, Martin A.; Tax, David M. J.; Gillis, Ad J. M.; Dorssers, Lambert C. J.; Koestler, Devin C.; de Ridder, Jeroen; Looijenga, Leendert H. J.

2015-01-01

The cell of origin of the five subtypes (I-V) of germ cell tumors (GCTs) are assumed to be germ cells from different maturation stages. This is (potentially) reflected in their methylation status as fetal maturing primordial germ cells are globally demethylated during migration from the yolk sac to the gonad. Imprinted regions are erased in the gonad and later become uniparentally imprinted according to fetal sex. Here, 91 GCTs (type I-IV) and four cell lines were profiled (Illumina’s HumanMethylation450BeadChip). Data was pre-processed controlling for cross hybridization, SNPs, detection rate, probe-type bias and batch effects. The annotation was extended, covering snRNAs/microRNAs, repeat elements and imprinted regions. A Hidden Markov Model-based genome segmentation was devised to identify differentially methylated genomic regions. Methylation profiles allowed for separation of clusters of non-seminomas (type II), seminomas/dysgerminomas (type II), spermatocytic seminomas (type III) and teratomas/dermoid cysts (type I/IV). The seminomas, dysgerminomas and spermatocytic seminomas were globally hypomethylated, in line with previous reports and their demethylated precursor. Differential methylation and imprinting status between subtypes reflected their presumed cell of origin. Ovarian type I teratomas and dermoid cysts showed (partial) sex specific uniparental maternal imprinting. The spermatocytic seminomas showed uniparental paternal imprinting while testicular teratomas exhibited partial imprinting erasure. Somatic imprinting in type II GCTs might indicate a cell of origin after global demethylation but before imprinting erasure. This is earlier than previously described, but agrees with the totipotent/embryonic stem cell like potential of type II GCTs and their rare extra-gonadal localization. The results support the common origin of the type I teratomas and show strong similarity between ovarian type I teratomas and dermoid cysts. In conclusion, we identified specific and global methylation differences between GCT subtypes, providing insight into their developmental timing and underlying developmental biology. Data and extended annotation are deposited at GEO (GSE58538 and GPL18809). PMID:25859847

Surfing the wave, cycle, life history, and genes/proteins expressed by testicular germ cells. Part 5: intercellular junctions and contacts between germs cells and Sertoli cells and their regulatory interactions, testicular cholesterol, and genes/proteins associated with more than one germ cell generation.

PubMed

Hermo, Louis; Pelletier, R-Marc; Cyr, Daniel G; Smith, Charles E

2010-04-01

In the testis, cell adhesion and junctional molecules permit specific interactions and intracellular communication between germ and Sertoli cells and apposed Sertoli cells. Among the many adhesion family of proteins, NCAM, nectin and nectin-like, catenins, and cadherens will be discussed, along with gap junctions between germ and Sertoli cells and the many members of the connexin family. The blood-testis barrier separates the haploid spermatids from blood borne elements. In the barrier, the intercellular junctions consist of many proteins such as occludin, tricellulin, and claudins. Changes in the expression of cell adhesion molecules are also an essential part of the mechanism that allows germ cells to move from the basal compartment of the seminiferous tubule to the adluminal compartment thus crossing the blood-testis barrier and well-defined proteins have been shown to assist in this process. Several structural components show interactions between germ cells to Sertoli cells such as the ectoplasmic specialization which are more closely related to Sertoli cells and tubulobulbar complexes that are processes of elongating spermatids embedded into Sertoli cells. Germ cells also modify several Sertoli functions and this also appears to be the case for residual bodies. Cholesterol plays a significant role during spermatogenesis and is essential for germ cell development. Lastly, we list genes/proteins that are expressed not only in any one specific generation of germ cells but across more than one generation. Copyright 2009 Wiley-Liss, Inc.

Male Rat Germ Cells Display Age-Dependent and Cell-Specific Susceptibility in Response to Oxidative Stress Challenges1

PubMed Central

Selvaratnam, Johanna; Paul, Catriona; Robaire, Bernard

2015-01-01

For decades male germ cells were considered unaffected by aging, due to the fact that males continue to generate sperm into old age; however, evidence indicates that germ cells from aged males are of lower quality than those of young males. The current study examines the effects of aging on pachytene spermatocytes and round spermatids, and is the first study to culture these cells in isolation for an extended period. Our objective is to determine the cell-specific responses germ cells have to aging and oxidative insult. Culturing isolated germ cells from young and aged Brown Norway rats revealed that germ cells from aged males displayed an earlier decline in viability, elevated levels of reactive oxygen species (ROS), and increased spermatocyte DNA damage, compared to young males. Furthermore, oxidative insult by prooxidant 3-morpholinosydnonimine provides insight into how spermatocytes and spermatids manage excess ROS. Genome-wide microarray analyses revealed that several transcripts for antioxidants, Sod1, Cat, and Prdxs, were up-regulated in response to ROS in germ cells from young males while being expressed at lower levels in the aged. In contrast, the expression of DNA damage repair genes Rad50 and Atm were increased in the germ cells from aged animals. Our data indicate that as germ cells undergo spermatogenesis, they adapt and respond to oxidative stress differently, depending on their phase of development, and the process of aging results in redox dysfunction. Thus, even at early stages of spermatogenesis, germ cells from aged males are unable to mount an appropriate response to manage oxidative stress. PMID:26224006

Light and electron microscopic analyses of Vasa expression in adult germ cells of the fish medaka.

PubMed

Yuan, Yongming; Li, Mingyou; Hong, Yunhan

2014-07-15

Germ cells of diverse animal species have a unique membrane-less organelle called germ plasm (GP). GP is usually associated with mitochondria and contains RNA binding proteins and mRNAs of germ genes such as vasa. GP has been described as the mitochondrial cloud (MC), intermitochondrial cement (IC) and chromatoid body (CB). The mechanism underlying varying GP structures has remained incompletely understood. Here we report the analysis of GP through light and electron microscopy by using Vasa as a marker in adult male germ cells of the fish medaka (Oryzias latipes). Immunofluorescence light microscopy revealed germ cell-specific Vasa expression. Vasa is the most abundant in mitotic germ cells (oogonia and spermatogonia) and reduced in meiotic germ cells. Vasa in round spermatids exist as a spherical structure reminiscent of CB. Nanogold immunoelectron microscopy revealed subcellular Vasa redistribution in male germ cells. Vasa in spermatogonia concentrates in small areas of the cytoplasm and is surrounded by mitochondria, which is reminiscent of MC. Vasa is intermixed with mitochondria to form IC in primary spermatocytes, appears as the free cement (FC) via separation from mitochondria in secondary spermatocyte and becomes condensed in CB at the caudal pole of round spermatids. During spermatid morphogenesis, Vasa redistributes and forms a second CB that is a ring-like structure surrounding the dense fiber of the flagellum in the midpiece. These structures resemble those described for GP in various species. Thus, Vasa identifies GP and adopts varying structures via dynamic reorganization at different stages of germ cell development. Copyright © 2014 Elsevier B.V. All rights reserved.

The Crystal Structure of the Drosophila Germline Inducer Oskar Identifies Two Domains with Distinct Vasa Helicase- and RNA-Binding Activities.

PubMed

Jeske, Mandy; Bordi, Matteo; Glatt, Sebastian; Müller, Sandra; Rybin, Vladimir; Müller, Christoph W; Ephrussi, Anne

2015-07-28

In many animals, the germ plasm segregates germline from soma during early development. Oskar protein is known for its ability to induce germ plasm formation and germ cells in Drosophila. However, the molecular basis of germ plasm formation remains unclear. Here, we show that Oskar is an RNA-binding protein in vivo, crosslinking to nanos, polar granule component, and germ cell-less mRNAs, each of which has a role in germline formation. Furthermore, we present high-resolution crystal structures of the two Oskar domains. RNA-binding maps in vitro to the C-terminal domain, which shows structural similarity to SGNH hydrolases. The highly conserved N-terminal LOTUS domain forms dimers and mediates Oskar interaction with the germline-specific RNA helicase Vasa in vitro. Our findings suggest a dual function of Oskar in RNA and Vasa binding, providing molecular clues to its germ plasm function. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Physicochemical properties of nixtamalized corn flours with and without germ.

PubMed

Vega Rojas, Lineth J; Rojas Molina, Isela; Gutiérrez Cortez, Elsa; Rincón Londoño, Natalia; Acosta Osorio, Andrés A; Del Real López, Alicia; Rodríguez García, Mario E

2017-04-01

This research studied the influence of the germ components on the physicochemical properties of cooked corn and nixtamalized corn flours as a function of the calcium hydroxide content (from 0 to 2.1 w/w) and steeping time (between 0 and 9h). A linear relationship was found between calcium content in germ and steeping time used during nixtamalization process. X-ray diffraction analysis showed that calcium carbonate is formed into the germ structure to 2.1 w/w of calcium hydroxide and 9h steeping time. The presence of the germ improves the development of peak viscosity in flours, and it is related to the increases in calcium concentration in germ and the formation of amylose-lipid complexes. No significant changes were observed in palmitic, stearic, oleic and linoleic acids of corn oil. The levels of further corn oil deterioration were 2.1 w/w of calcium hydroxide concentration and 9h of steeping time. Copyright © 2016 Elsevier Ltd. All rights reserved.

Multimodel assessment of BRCA1 mutations in Taiwanese (ethnic Chinese) women with early-onset, bilateral or familial breast cancer.

PubMed

Kuo, Wen-Hong; Lin, Po-Han; Huang, Ai-Chu; Chien, Yin-Hsiu; Liu, Tsang-Pai; Lu, Yen-Shen; Bai, Li-Yuan; Sargeant, Aaron M; Lin, Ching-Hung; Cheng, Ann-Lii; Hsieh, Fon-Jou; Hwu, Wuh-Liang; Chang, King-Jen

2012-02-01

Although evidence suggests an importance of genetic factors in the development of breast cancer in Taiwanese (ethnic Chinese) women, including a high incidence of early-onset and secondary contralateral breast cancer, a major breast cancer predisposition gene, BRCA1, has not been well studied in this population. In fact, the carcinogenic impacts of many genetic variants of BRCA1 are unknown and classified as variants of uncertain significance (VUS). It is therefore important to establish a method to characterize the BRCA1 VUSs and understand their role in Taiwanese breast cancer patients. Accordingly, we developed a multimodel assessment strategy consisting of a prescreening portion and a validated functional assay to study breast cancer patients with early-onset, bilateral or familial breast cancer. We found germ-line BRCA1 mutations in 11.1% of our cohort and identified one novel missense mutation, c.5191C>A. Two genetic variants were initially classified as VUSs (c.1155C>T and c.5191C>A). c.1155C>T is not predicted to be deleterious in the prescreening portion of our assessment strategy. c.5191C>A, on the other hand, causes p.T1691K, which is predicted to have high deleterious probability because of significant structural alteration, a high deleterious score in the predictive programs and, clinically, triple negative characteristics in breast tumors. This mutant is confirmed by transcription activation and yeast growth-inhibition assays. In conclusion, we show as high a prevalence of germ-line BRCA1 mutation in high-risk Taiwanese patients as in Caucasians and demonstrate a useful strategy for studying BRCA1 VUSs.

A switch in the mode of Wnt signaling orchestrates the formation of germline stem cell differentiation niche in Drosophila

PubMed Central

Upadhyay, Maitreyi; Kuna, Michael; Tudor, Sara; Martino Cortez, Yesenia

2018-01-01

Germline stem cell (GSC) self-renewal and differentiation into gametes is regulated by both intrinsic factors in the germ line as well as extrinsic factors from the surrounding somatic niche. dWnt4, in the escort cells of the adult somatic niche promotes GSC differentiation using the canonical β-catenin-dependent transcriptional pathway to regulate escort cell survival, adhesion to the germ line and downregulation of self-renewal signaling. Here, we show that in addition to the β-catenin-dependent canonical pathway, dWnt4 also uses downstream components of the Wnt non-canonical pathway to promote escort cell function earlier in development. We find that the downstream non-canonical components, RhoA, Rac1 and cdc42, are expressed at high levels and are active in escort cell precursors of the female larval gonad compared to the adult somatic niche. Consistent with this expression pattern, we find that the non-canonical pathway components function in the larval stages but not in adults to regulate GSC differentiation. In the larval gonad, dWnt4, RhoA, Rac1 and cdc42 are required to promote intermingling of escort cell precursors, a function that then promotes proper escort cell function in the adults. We find that dWnt4 acts by modulating the activity of RhoA, Rac1 and cdc42, but not their protein levels. Together, our results indicate that at different points of development, dWnt4 switches from using the non-canonical pathway components to using a β-catenin-dependent canonical pathway in the escort cells to facilitate the proper differentiation of GSCs. PMID:29370168

New insights into human primordial germ cells and early embryonic development from single-cell analysis.

PubMed

Otte, Jörg; Wruck, Wasco; Adjaye, James

2017-08-01

Human preimplantation developmental studies are difficult to accomplish due to associated ethical and moral issues. Preimplantation cells are rare and exist only in transient cell states. From a single cell, it is very challenging to analyse the origination of the heterogeneity and complexity inherent to the human body. However, recent advances in single-cell technology and data analysis have provided new insights into the process of early human development and germ cell specification. In this Review, we examine the latest single-cell datasets of human preimplantation embryos and germ cell development, compare them to bulk cell analyses, and interpret their biological implications. © 2017 Federation of European Biochemical Societies.

Germ cell tumors: Insights from the Drosophila ovary and the mouse testis.

PubMed

Salz, Helen K; Dawson, Emily P; Heaney, Jason D

2017-03-01

Ovarian and testicular germ cell tumors of young adults are thought to arise from defects in germ cell development, but the molecular mechanisms underlying malignant transformation are poorly understood. In this review, we focus on the biology of germ cell tumor formation in the Drosophila ovary and the mouse testis, for which evidence supports common underlying mechanisms, such as blocking initiation into the differentiation pathway, impaired lineage progression, and sexual identity instability. We then discuss how these concepts inform our understanding of the disease in humans. Mol. Reprod. Dev. 84: 200-211, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

GLD-4-Mediated Translational Activation Regulates the Size of the Proliferative Germ Cell Pool in the Adult C. elegans Germ Line

PubMed Central

Millonigg, Sophia; Eckmann, Christian R.

2014-01-01

To avoid organ dysfunction as a consequence of tissue diminution or tumorous growth, a tight balance between cell proliferation and differentiation is maintained in metazoans. However, cell-intrinsic gene expression mechanisms controlling adult tissue homeostasis remain poorly understood. By focusing on the adult Caenorhabditis elegans reproductive tissue, we show that translational activation of mRNAs is a fundamental mechanism to maintain tissue homeostasis. Our genetic experiments identified the Trf4/5-type cytoplasmic poly(A) polymerase (cytoPAP) GLD-4 and its enzymatic activator GLS-1 to perform a dual role in regulating the size of the proliferative zone. Consistent with a ubiquitous expression of GLD-4 cytoPAP in proliferative germ cells, its genetic activity is required to maintain a robust proliferative adult germ cell pool, presumably by regulating many mRNA targets encoding proliferation-promoting factors. Based on translational reporters and endogenous protein expression analyses, we found that gld-4 activity promotes GLP-1/Notch receptor expression, an essential factor of continued germ cell proliferation. RNA-protein interaction assays documented also a physical association of the GLD-4/GLS-1 cytoPAP complex with glp-1 mRNA, and ribosomal fractionation studies established that GLD-4 cytoPAP activity facilitates translational efficiency of glp-1 mRNA. Moreover, we found that in proliferative cells the differentiation-promoting factor, GLD-2 cytoPAP, is translationally repressed by the stem cell factor and PUF-type RNA-binding protein, FBF. This suggests that cytoPAP-mediated translational activation of proliferation-promoting factors, paired with PUF-mediated translational repression of differentiation factors, forms a translational control circuit that expands the proliferative germ cell pool. Our additional genetic experiments uncovered that the GLD-4/GLS-1 cytoPAP complex promotes also differentiation, forming a redundant translational circuit with GLD-2 cytoPAP and the translational repressor GLD-1 to restrict proliferation. Together with previous findings, our combined data reveals two interconnected translational activation/repression circuitries of broadly conserved RNA regulators that maintain the balance between adult germ cell proliferation and differentiation. PMID:25254367

Germ tube and chlamydospore formation by Candida albicans on a new medium.

PubMed Central

Beheshti, F; Smith, A G; Krause, G W

1975-01-01

A new medium composed of "cream of rice" infusion, oxgall, Tween 80, and agar is described for the sequential development of germ tubes and chlamydospores by Candida albicans. The procedure used (Dalmau's technique) is an improvement over the fluid substrate procedures previously advocated for germ tube formation. That the same preparation is then used for chlamydospore production is of practical importance for the clinical mycology laboratory. Images PMID:1102561

Nanosecond pulsed electric field suppresses development of eyes and germ cells through blocking synthesis of retinoic acid in Medaka (Oryzias latipes).

PubMed

Shiraishi, Eri; Hosseini, Hamid; Kang, Dong K; Kitano, Takeshi; Akiyama, Hidenori

2013-01-01

Application of nanosecond pulsed electric fields (nsPEFs) has attracted rising attention in various scientific fields including medical, pharmacological, and biological sciences, although its effects and molecular mechanisms leading to the effects remain poorly understood. Here, we show that a single, high-intensity (10-30 kV/cm), 60-ns PEF exposure affects gene expression and impairs development of eyes and germ cells in medaka (Oryzias latipes). Exposure of early blastula stage embryos to nsPEF down-regulated the expression of several transcription factors which are essential for eye development, causing abnormal eye formation. Moreover, the majority of the exposed genetic female embryos showed a fewer number of germ cells similar to that of the control (unexposed) genetic male at 9 days post-fertilization (dpf). However, all-trans retinoic acid (atRA) treatment following the exposure rescued proliferation of germ cells and resumption of normal eye development, suggesting that the phenotypes induced by nsPEF are caused by a decrease of retinoic acid levels. These results confirm that nsPEFs induce novel effects during embryogenesis in medaka.

Human primordial germ cell formation is diminished by exposure to environmental toxicants acting through the AHR signaling pathway.

PubMed

Kee, Kehkooi; Flores, Martha; Cedars, Marcelle I; Reijo Pera, Renee A

2010-09-01

Historically, effects of environmental toxicants on human development have been deduced via epidemiological studies because direct experimental analysis has not been possible. However, in recent years, the derivation of human pluripotent stem cells has provided a potential experimental system to directly probe human development. Here, we used human embryonic stem cells (hESCs) to study the effect of environmental toxicants on human germ cell development, with a focus on differentiation of the founding population of primordial germ cells (PGCs), which will go on to form the oocytes of the adult. We demonstrate that human PGC numbers are specifically reduced by exposure to polycyclic aromatic hydrocarbons (PAHs), a group of toxicants common in air pollutants released from gasoline combustion or tobacco smoke. Further, we demonstrate that the adverse effects of PAH exposure are mediated through the aromatic hydrocarbon receptor (AHR) and BAX pathway. This study demonstrates the utility of hESCs as a model system for direct examination of the molecular and genetic pathways of environmental toxicants on human germ cell development.

Modification of tooth development by heat shock protein 60

PubMed Central

Papp, Tamas; Polyak, Angela; Papp, Krisztina; Meszar, Zoltan; Zakany, Roza; Meszar-Katona, Eva; Tünde, Palne Terdik; Ham, Chang Hwa; Felszeghy, Szabolcs

2016-01-01

Although several heat shock proteins have been investigated in relation to tooth development, no available information is available about the spatial and temporal expression pattern of heat shock protein 60 (Hsp 60). To characterize Hsp 60 expression in the structures of the developing tooth germ, we used Western blotting, immunohistochemistry and in situ hybridization. Hsp 60 was present in high amounts in the inner and outer enamel epithelia, enamel knot (EK) and stratum intermedium (SI). Hsp 60 also appeared in odontoblasts beginning in the bell stage. To obtain data on the possible effect of Hsp 60 on isolated lower incisors from mice, we performed in vitro culturing. To investigate the effect of exogenous Hsp 60 on the cell cycle during culturing, we used the 5-bromo-2-deoxyuridine (BrdU) incorporation test on dental cells. Exogenously administered Hsp 60 caused bluntness at the apical part of the 16.5-day-old tooth germs, but it did not influence the proliferation rate of dental cells. We identified the expression of Hsp 60 in the developing tooth germ, which was present in high concentrations in the inner and outer enamel epithelia, EK, SI and odontoblasts. High concentration of exogenous Hsp 60 can cause abnormal morphology of the tooth germ, but it did not influence the proliferation rate of the dental cells. Our results suggest that increased levels of Hsp 60 may cause abnormalities in the morphological development of the tooth germ and support the data on the significance of Hsp during the developmental processes. PMID:27025262

Generation and characterization of human iPSC line generated from mesenchymal stem cells derived from adipose tissue.

PubMed

Zapata-Linares, Natalia; Rodriguez, Saray; Mazo, Manuel; Abizanda, Gloria; Andreu, Enrique J; Barajas, Miguel; Prosper, Felipe; Rodriguez-Madoz, Juan R

2016-01-01

In this work, mesenchymal stem cells derived from adipose tissue (ADSCs) were used for the generation of the human-induced pluripotent stem cell line G15.AO. Cell reprogramming was performed using retroviral vectors containing the Yamanaka factors, and the generated G15.AO hiPSC line showed normal karyotype, silencing of the exogenous reprogramming factors, induction of the typical pluripotency-associated markers, alkaline phosphatase enzymatic activity, and in vivo and in vitro differentiation ability to the three germ layers. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

The promise of human embryonic stem cells in aging-associated diseases

PubMed Central

Yabut, Odessa; Bernstein, Harold S.

2011-01-01

Aging-associated diseases are often caused by progressive loss or dysfunction of cells that ultimately affect the overall function of tissues and organs. Successful treatment of these diseases could benefit from cell-based therapy that would regenerate lost cells or otherwise restore tissue function. Human embryonic stem cells (hESCs) promise to be an important therapeutic candidate in treating aging-associated diseases due to their unique capacity for self-renewal and pluripotency. To date, there are numerous hESC lines that have been developed and characterized. We will discuss how hESC lines are derived, their molecular and cellular properties, and how their ability to differentiate into all three embryonic germ layers is determined. We will also outline the methods currently employed to direct their differentiation into populations of tissue-specific, functional cells. Finally, we will highlight the general challenges that must be overcome and the strategies being developed to generate highly-purified hESC-derived cell populations that can safely be used for clinical applications. PMID:21566262

Establishment of intraperitoneal germ cell transplantation for critically endangered Chinese sturgeon Acipenser sinensis.

PubMed

Ye, Huan; Li, Chuang-Ju; Yue, Hua-Mei; Du, Hao; Yang, Xiao-Ge; Yoshino, Tasuku; Hayashida, Takao; Takeuchi, Yutaka; Wei, Qi-Wei

2017-05-01

Recent progress in germ cell transplantation techniques in fish has paved the way for the conservation of endangered species. Here, we developed an intraperitoneal germ cell transplantation procedure using Chinese and Dabry's sturgeon as donor and recipient species, respectively. Histological analysis revealed that primordial germ cells migrated on the peritoneal wall at 16 days post-hatch (dph) in Dabry's sturgeon. The genital ridges of Dabry's sturgeon (recipient) first formed at 28 dph, suggesting that for successful colonization of donor germ cells in the recipient gonads, the transplantation should be performed earlier than this age. Sexual dimorphism of gonadal structure was first observed at 78 dph. Gonadal germ cell proliferation was not seen in either sex during this period. Immunohistochemistry using the anti-Vasa antibody found that donor testes from 2-year-old Dabry's sturgeon mainly consisted of single- or paired-type A spermatogonia, while donor ovaries from 11.5-year-old Chinese sturgeon had perinucleolus stage oocytes and clusters of oogonia. Donor cells isolated from Dabry's sturgeon testes or Chinese sturgeon ovary labeled with PKH26 fluorescent dye were transplanted into the peritoneal cavity of the 7- or 8-dph Dabry's sturgeon larvae. More than 90% and 70% of transplanted larvae survived after 2 days post-transplantation (dpt) and 51 dpt, respectively. At 51 dpt, PKH26-labeled cells exhibiting germ cell-specific nuclear morphology and diameter were observed in excised recipient gonads by fluorescent and confocal microscopy. The colonization rate of allogeneic testicular germ cell transplantation (Group 1) was 70%, while that of two batches of xenogeneic ovarian germ cell transplantation (Group 2 and Group 3) were 6.7% and 40%, respectively. The ratio of colonized germ cells to endogenous germ cells was 11.96%, 5.35% and 3.56% for Group 1, Group 2 and Group 3, respectively. Thus, we established a germ cell transplantation technique for the critically endangered Chinese sturgeon using the most closely related species as a recipient and demonstrated the successful preparation of transplantable female germ cells from aged adult Chinese sturgeon. Copyright © 2017 Elsevier Inc. All rights reserved.

A novel approach using long‐read sequencing and ddPCR to investigate gonadal mosaicism and estimate recurrence risk in two families with developmental disorders

PubMed Central

Gudmundsson, Sanna; Johansson, Josefin; Ameur, Adam; Stattin, Eva‐Lena; Annerén, Göran; Malmgren, Helena; Frykholm, Carina

2017-01-01

Abstract Objective De novo mutations contribute significantly to severe early‐onset genetic disorders. Even if the mutation is apparently de novo, there is a recurrence risk due to parental germ line mosaicism, depending on in which gonadal generation the mutation occurred. Methods We demonstrate the power of using SMRT sequencing and ddPCR to determine parental origin and allele frequencies of de novo mutations in germ cells in two families whom had undergone assisted reproduction. Results In the first family, a TCOF1 variant c.3156C>T was identified in the proband with Treacher Collins syndrome. The variant affects splicing and was determined to be of paternal origin. It was present in <1% of the paternal germ cells, suggesting a very low recurrence risk. In the second family, the couple had undergone several unsuccessful pregnancies where a de novo mutation PTPN11 c.923A>C causing Noonan syndrome was identified. The variant was present in 40% of the paternal germ cells suggesting a high recurrence risk. Conclusions Our findings highlight a successful strategy to identify the parental origin of mutations and to investigate the recurrence risk in couples that have undergone assisted reproduction with an unknown donor or in couples with gonadal mosaicism that will undergo preimplantation genetic diagnosis. PMID:28921562

A novel approach using long-read sequencing and ddPCR to investigate gonadal mosaicism and estimate recurrence risk in two families with developmental disorders.

PubMed

Wilbe, Maria; Gudmundsson, Sanna; Johansson, Josefin; Ameur, Adam; Stattin, Eva-Lena; Annerén, Göran; Malmgren, Helena; Frykholm, Carina; Bondeson, Marie-Louise

2017-11-01

De novo mutations contribute significantly to severe early-onset genetic disorders. Even if the mutation is apparently de novo, there is a recurrence risk due to parental germ line mosaicism, depending on in which gonadal generation the mutation occurred. We demonstrate the power of using SMRT sequencing and ddPCR to determine parental origin and allele frequencies of de novo mutations in germ cells in two families whom had undergone assisted reproduction. In the first family, a TCOF1 variant c.3156C>T was identified in the proband with Treacher Collins syndrome. The variant affects splicing and was determined to be of paternal origin. It was present in <1% of the paternal germ cells, suggesting a very low recurrence risk. In the second family, the couple had undergone several unsuccessful pregnancies where a de novo mutation PTPN11 c.923A>C causing Noonan syndrome was identified. The variant was present in 40% of the paternal germ cells suggesting a high recurrence risk. Our findings highlight a successful strategy to identify the parental origin of mutations and to investigate the recurrence risk in couples that have undergone assisted reproduction with an unknown donor or in couples with gonadal mosaicism that will undergo preimplantation genetic diagnosis. © 2017 The Authors Prenatal Diagnosis published by John Wiley & Sons Ltd.

miRNA-1297 induces cell proliferation by targeting phosphatase and tensin homolog in testicular germ cell tumor cells.

PubMed

Yang, Nian-Qin; Zhang, Jian; Tang, Qun-Ye; Guo, Jian-Ming; Wang, Guo-Min

2014-01-01

To investigate the role of miR-1297 and the tumor suppressor gene PTEN in cell proliferation of testicular germ cell tumors (TGCT). MTT assays were used to test the effect of miR-1297 on proliferation of the NCCIT testicular germ cell tumor cell line. In NCCIT cells, the expression of PTEN was assessed by Western blotting further. In order to confirm target association between miR-1297 and 3'-UTR of PTEN, a luciferase reporter activity assay was employed. Moreover, roles of PTEN in proliferation of NCCIT cells were evaluated by transfection of PTEN siRNA. Proliferation of NCCIT cells was promoted by miR-1297 in a concentration-dependent manner. In addition, miR-1297 could bind to the 3'-UTR of PTEN based on luciferase reporter activity assay, and reduced expression of PTEN at protein level was found. Proliferation of NCCIT cells was significantly enhanced after knockdown of PTEN by siRNA. miR-1297 as a potential oncogene could induce cell proliferation by targeting PTEN in NCCIT cells.

Pluripotent cells in farm animals: state of the art and future perspectives.

PubMed

Nowak-Imialek, Monika; Niemann, Heiner

2012-01-01

Pluripotent cells, such as embryonic stem (ES) cells, embryonic germ cells and embryonic carcinoma cells are a unique type of cell because they remain undifferentiated indefinitely in in vitro culture, show self-renewal and possess the ability to differentiate into derivatives of the three germ layers. These capabilities make them a unique in vitro model for studying development, differentiation and for targeted modification of the genome. True pluripotent ESCs have only been described in the laboratory mouse and rat. However, rodent physiology and anatomy differ substantially from that of humans, detracting from the value of the rodent model for studies of human diseases and the development of cellular therapies in regenerative medicine. Recently, progress in the isolation of pluripotent cells in farm animals has been made and new technologies for reprogramming of somatic cells into a pluripotent state have been developed. Prior to clinical application of therapeutic cells differentiated from pluripotent stem cells in human patients, their survival and the absence of tumourigenic potential must be assessed in suitable preclinical large animal models. The establishment of pluripotent cell lines in farm animals may provide new opportunities for the production of transgenic animals, would facilitate development and validation of large animal models for evaluating ESC-based therapies and would thus contribute to the improvement of human and animal health. This review summarises the recent progress in the derivation of pluripotent and reprogrammed cells from farm animals. We refer to our recent review on this area, to which this article is complementary.

The Caenorhabditis elegans LET-418/Mi2 plays a conserved role in lifespan regulation.

PubMed

De Vaux, Véronique; Pfefferli, Catherine; Passannante, Myriam; Belhaj, Khaoula; von Essen, Alina; Sprecher, Simon G; Müller, Fritz; Wicky, Chantal

2013-12-01

The evolutionarily conserved nucleosome-remodeling protein Mi2 is involved in transcriptional repression during development in various model systems, plays a role in embryonic patterning and germ line development, and participates in DNA repair and cell cycle progression. It is the catalytic subunit of the nucleosome remodeling and histone deacetylase (NuRD) complex, a key determinant of differentiation in mammalian embryonic stem cells. In addition, the Drosophila and C. elegans Mi2 homologs participate in another complex, the MEC complex, which also plays an important developmental role in these organisms. Here we show a new and unexpected feature of the C. elegans Mi2 homolog, LET-418/Mi2. Lack of LET-418/Mi2 results in longevity and enhanced stress resistance, a feature that we found to be conserved in Drosophila and in Arabidopsis. The fact that depletion of other components of the NuRD and the MEC complexes did not result in longevity suggests that LET-418 may regulate lifespan in a different molecular context. Genetic interaction studies suggest that let-418 could act in the germ-cell-loss pathway, downstream of kri-1 and tcer-1. On the basis of our data and on previous findings showing a role for let-418 during development, we propose that LET-418/Mi2 could be part of a system that drives development and reproduction with concomitant life-reducing effects later in life. © 2013 the Anatomical Society and John Wiley & Sons Ltd.

Corrective recombination of mouse immunoglobulin kappa alleles in Abelson murine leukemia virus-transformed pre-B cells.

PubMed Central

Feddersen, R M; Van Ness, B G

1990-01-01

Previous characterization of mouse immunoglobulin kappa gene rearrangement products cloned from murine plasmacytomas has indicated that two recombination events can take place on a single kappa allele (R. M. Feddersen and B. G. Van Ness, Proc. Natl. Acad. Sci. USA 82:4792-4797, 1985; M. A. Shapiro and M. Weigert, J. Immunol. 139:3834-3839, 1987). To determine whether multiple recombinations on a single kappa allele can contribute to the formation of productive V-J genes through corrective recombinations, we have examined several Abelson murine leukemia virus-transformed pre-B-cell clones which rearrange the kappa locus during cell culture. Clonal cell lines which had rearranged one kappa allele nonproductively while maintaining the other allele in the germ line configuration were grown, and secondary subclones, which subsequently expressed kappa protein, were isolated and examined for further kappa rearrangement. A full spectrum of rearrangement patterns was observed in this sequential cloning, including productive and nonproductive recombinations of the germ line allele and secondary recombinations of the nonproductive allele. The results show that corrective V-J recombinations, with displacement of the nonproductive kappa gene, occur with a significant frequency (6 of 17 kappa-producing subclones). Both deletion and maintenance of the primary (nonfunctional) V-J join, as a reciprocal product, were observed. Images PMID:2153918

Regulation of proliferation in developing human tooth germs by MSX homeodomain proteins and cyclin-dependent kinase inhibitor p19INK4d.

PubMed

Kero, Darko; Vukojevic, Katarina; Stazic, Petra; Sundov, Danijela; Mardesic Brakus, Snjezana; Saraga-Babic, Mirna

2017-10-02

Before the secretion of hard dental tissues, tooth germs undergo several distinctive stages of development (dental lamina, bud, cap and bell). Every stage is characterized by specific proliferation patterns, which is regulated by various morphogens, growth factors and homeodomain proteins. The role of MSX homeodomain proteins in odontogenesis is rather complex. Expression domains of genes encoding for murine Msx1/2 during development are observed in tissues containing highly proliferative progenitor cells. Arrest of tooth development in Msx knockout mice can be attributed to impaired proliferation of progenitor cells. In Msx1 knockout mice, these progenitor cells start to differentiate prematurely as they strongly express cyclin-dependent kinase inhibitor p19 INK4d . p19 INK4d induces terminal differentiation of cells by blocking the cell cycle in mitogen-responsive G1 phase. Direct suppression of p19 INK4d by Msx1 protein is, therefore, important for maintaining proliferation of progenitor cells at levels required for the normal progression of tooth development. In this study, we examined the expression patterns of MSX1, MSX2 and p19 INK4d in human incisor tooth germs during the bud, cap and early bell stages of development. The distribution of expression domains of p19 INK4d throughout the investigated period indicates that p19 INK4d plays active role during human tooth development. Furthermore, comparison of expression domains of p19 INK4d with those of MSX1, MSX2 and proliferation markers Ki67, Cyclin A2 and pRb, indicates that MSX-mediated regulation of proliferation in human tooth germs might not be executed by the mechanism similar to one described in developing tooth germs of wild-type mouse.

Two Classes of Gap Junction Channels Mediate Soma-Germline Interactions Essential for Germline Proliferation and Gametogenesis in Caenorhabditis elegans

PubMed Central

Starich, Todd A.; Hall, David H.; Greenstein, David

2014-01-01

In all animals examined, somatic cells of the gonad control multiple biological processes essential for germline development. Gap junction channels, composed of connexins in vertebrates and innexins in invertebrates, permit direct intercellular communication between cells and frequently form between somatic gonadal cells and germ cells. Gap junctions comprise hexameric hemichannels in apposing cells that dock to form channels for the exchange of small molecules. Here we report essential roles for two classes of gap junction channels, composed of five innexin proteins, in supporting the proliferation of germline stem cells and gametogenesis in the nematode Caenorhabditis elegans. Transmission electron microscopy of freeze-fracture replicas and fluorescence microscopy show that gap junctions between somatic cells and germ cells are more extensive than previously appreciated and are found throughout the gonad. One class of gap junctions, composed of INX-8 and INX-9 in the soma and INX-14 and INX-21 in the germ line, is required for the proliferation and differentiation of germline stem cells. Genetic epistasis experiments establish a role for these gap junction channels in germline proliferation independent of the glp-1/Notch pathway. A second class of gap junctions, composed of somatic INX-8 and INX-9 and germline INX-14 and INX-22, is required for the negative regulation of oocyte meiotic maturation. Rescue of gap junction channel formation in the stem cell niche rescues germline proliferation and uncovers a later channel requirement for embryonic viability. This analysis reveals gap junctions as a central organizing feature of many soma–germline interactions in C. elegans. PMID:25195067

Recent advances of in vitro culture systems for spermatogonial stem cells in mammals.

PubMed

Sahare, Mahesh G; Suyatno; Imai, Hiroshi

2018-04-01

Spermatogonial stem cells (SSCs) in the mammalian testis are unipotent stem cells for spermatozoa. They show unique cell characteristics as stem cells and germ cells after being isolated from the testis and cultured in vitro. This review introduces recent progress in the development of culture systems for the establishment of SSC lines in mammalian species, including humans. Based on the published reports, the isolation and purification of SSCs, identification and characteristics of SSCs, and culture system for mice, humans, and domestic animals have been summarized. In mice, cell lines from SSCs are established and can be reprogrammed to show pluripotent stem cell potency that is similar to embryonic stem cells. However, it is difficult to establish cell lines for animals other than mice because of the dearth of understanding about species-specific requirements for growth factors and mechanisms supporting the self-renewal of cultured SSCs. Among the factors that are associated with the development of culture systems, the enrichment of SSCs that are isolated from the testis and the combination of growth factors are essential. Providing an example of SSC culture in cattle, a rational consideration was made about how it can be possible to establish cell lines from neonatal and immature testes.

"Life in a Germ-Free World":

PubMed Central

Kirk, Robert G. W.

2012-01-01

Summary: This article examines a specific technology, the germ-free "isolator," tracing its development across three sites: (1) the laboratory for the production of standard laboratory animals, (2) agriculture for the efficient production of farm animals, and (3) the hospital for the control and prevention of cross-infection and the protection of individuals from infection. Germ-free technology traveled across the laboratory sciences, clinical and veterinary medicine, and industry, yet failed to become institutionalized outside the laboratory. That germ-free technology worked was not at issue. Working, however, was not enough. Examining the history of a technology that failed to find widespread application reveals the labor involved in aligning cultural, societal, and material factors necessary for successful medical innovation. PMID:23000838

Cancer treatment in childhood and testicular function: the importance of the somatic environment.

PubMed

Stukenborg, Jan-Bernd; Jahnukainen, Kirsi; Hutka, Marsida; Mitchell, Rod T

2018-02-01

Testicular function and future fertility may be affected by cancer treatment during childhood. Whilst survival of the germ (stem) cells is critical for ensuring the potential for fertility in these patients, the somatic cell populations also play a crucial role in providing a suitable environment to support germ cell maintenance and subsequent development. Regulation of the spermatogonial germ-stem cell niche involves many signalling pathways with hormonal influence from the hypothalamo-pituitary-gonadal axis. In this review, we describe the somatic cell populations that comprise the testicular germ-stem cell niche in humans and how they may be affected by cancer treatment during childhood. We also discuss the experimental models that may be utilized to manipulate the somatic environment and report the results of studies that investigate the potential role of somatic cells in the protection of the germ cells in the testis from cancer treatment. © 2018 The authors.

Cancer treatment in childhood and testicular function: the importance of the somatic environment

PubMed Central

Stukenborg, Jan-Bernd; Jahnukainen, Kirsi; Hutka, Marsida

2018-01-01

Testicular function and future fertility may be affected by cancer treatment during childhood. Whilst survival of the germ (stem) cells is critical for ensuring the potential for fertility in these patients, the somatic cell populations also play a crucial role in providing a suitable environment to support germ cell maintenance and subsequent development. Regulation of the spermatogonial germ-stem cell niche involves many signalling pathways with hormonal influence from the hypothalamo-pituitary-gonadal axis. In this review, we describe the somatic cell populations that comprise the testicular germ-stem cell niche in humans and how they may be affected by cancer treatment during childhood. We also discuss the experimental models that may be utilized to manipulate the somatic environment and report the results of studies that investigate the potential role of somatic cells in the protection of the germ cells in the testis from cancer treatment. PMID:29351905

Evolutionary dynamics of endogenous feline leukemia virus proliferation among species of the domestic cat lineage.

PubMed

Polani, Sagi; Roca, Alfred L; Rosensteel, Bryan B; Kolokotronis, Sergios-Orestis; Bar-Gal, Gila Kahila

2010-09-30

Endogenous feline leukemia viruses (enFeLVs) occur in the germ lines of the domestic cat and related wild species (genus Felis). We sequenced the long terminal repeats and part of the env region of enFeLVs in domestic cats and five wild species. A total of 305 enFeLV sequences were generated across 17 individuals, demonstrating considerable diversity within two major clades. Distinct proliferations of enFeLVs occurred before and after the black-footed cat diverged from the other species. Diversity of enFeLVs was limited for the sand cat and jungle cat suggesting that proliferation of enFeLVs occurred within these species after they diverged. Relationships among enFeLVs were congruent with host species relationships except for the jungle cat, which carried only enFeLVs from a lineage that recently invaded the germline (enFeLV-AGTT). Comparison of wildcat and domestic cat enFeLVs indicated that a distinctive germ line invasion of enFeLVs has not occurred since the cat was domesticated. Copyright 2010 Elsevier Inc. All rights reserved.

Evolutionary dynamics of endogenous feline leukemia virus proliferation among species of the domestic cat lineage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Polani, Sagi, E-mail: sagi.polani@gmail.co; Roca, Alfred L., E-mail: roca@illinois.ed; Rosensteel, Bryan B., E-mail: bryanr1@umbc.ed

Endogenous feline leukemia viruses (enFeLVs) occur in the germ lines of the domestic cat and related wild species (genus Felis). We sequenced the long terminal repeats and part of the env region of enFeLVs in domestic cats and five wild species. A total of 305 enFeLV sequences were generated across 17 individuals, demonstrating considerable diversity within two major clades. Distinct proliferations of enFeLVs occurred before and after the black-footed cat diverged from the other species. Diversity of enFeLVs was limited for the sand cat and jungle cat suggesting that proliferation of enFeLVs occurred within these species after they diverged. Relationshipsmore » among enFeLVs were congruent with host species relationships except for the jungle cat, which carried only enFeLVs from a lineage that recently invaded the germline (enFeLV-AGTT). Comparison of wildcat and domestic cat enFeLVs indicated that a distinctive germ line invasion of enFeLVs has not occurred since the cat was domesticated.« less

A selfish DNA element engages a meiosis-specific motor and telomeres for germ-line propagation.

PubMed

Sau, Soumitra; Conrad, Michael N; Lee, Chih-Ying; Kaback, David B; Dresser, Michael E; Jayaram, Makkuni

2014-06-09

The chromosome-like mitotic stability of the yeast 2 micron plasmid is conferred by the plasmid proteins Rep1-Rep2 and the cis-acting locus STB, likely by promoting plasmid-chromosome association and segregation by hitchhiking. Our analysis reveals that stable plasmid segregation during meiosis requires the bouquet proteins Ndj1 and Csm4. Plasmid relocalization from the nuclear interior in mitotic cells to the periphery at or proximal to telomeres rises from early meiosis to pachytene. Analogous to chromosomes, the plasmid undergoes Csm4- and Ndj1-dependent rapid prophase movements with speeds comparable to those of telomeres. Lack of Ndj1 partially disrupts plasmid-telomere association without affecting plasmid colocalization with the telomere-binding protein Rap1. The plasmid appears to engage a meiosis-specific motor that orchestrates telomere-led chromosome movements for its telomere-associated segregation during meiosis I. This hitherto uncharacterized mode of germ-line transmission by a selfish genetic element signifies a mechanistic variation within the shared theme of chromosome-coupled plasmid segregation during mitosis and meiosis. © 2014 Sau et al.

A selfish DNA element engages a meiosis-specific motor and telomeres for germ-line propagation

PubMed Central

Sau, Soumitra; Conrad, Michael N.; Lee, Chih-Ying; Kaback, David B.; Dresser, Michael E.

2014-01-01

The chromosome-like mitotic stability of the yeast 2 micron plasmid is conferred by the plasmid proteins Rep1-Rep2 and the cis-acting locus STB, likely by promoting plasmid-chromosome association and segregation by hitchhiking. Our analysis reveals that stable plasmid segregation during meiosis requires the bouquet proteins Ndj1 and Csm4. Plasmid relocalization from the nuclear interior in mitotic cells to the periphery at or proximal to telomeres rises from early meiosis to pachytene. Analogous to chromosomes, the plasmid undergoes Csm4- and Ndj1-dependent rapid prophase movements with speeds comparable to those of telomeres. Lack of Ndj1 partially disrupts plasmid–telomere association without affecting plasmid colocalization with the telomere-binding protein Rap1. The plasmid appears to engage a meiosis-specific motor that orchestrates telomere-led chromosome movements for its telomere-associated segregation during meiosis I. This hitherto uncharacterized mode of germ-line transmission by a selfish genetic element signifies a mechanistic variation within the shared theme of chromosome-coupled plasmid segregation during mitosis and meiosis. PMID:24914236

Domestic chickens activate a piRNA defense against avian leukosis virus

PubMed Central

Sun, Yu Huining; Xie, Li Huitong; Zhuo, Xiaoyu; Chen, Qiang; Ghoneim, Dalia; Zhang, Bin; Jagne, Jarra; Yang, Chengbo; Li, Xin Zhiguo

2017-01-01

PIWI-interacting RNAs (piRNAs) protect the germ line by targeting transposable elements (TEs) through the base-pair complementarity. We do not know how piRNAs co-evolve with TEs in chickens. Here we reported that all active TEs in the chicken germ line are targeted by piRNAs, and as TEs lose their activity, the corresponding piRNAs erode away. We observed de novo piRNA birth as host responds to a recent retroviral invasion. Avian leukosis virus (ALV) has endogenized prior to chicken domestication, remains infectious, and threatens poultry industry. Domestic fowl produce piRNAs targeting ALV from one ALV provirus that was known to render its host ALV resistant. This proviral locus does not produce piRNAs in undomesticated wild chickens. Our findings uncover rapid piRNA evolution reflecting contemporary TE activity, identify a new piRNA acquisition modality by activating a pre-existing genomic locus, and extend piRNA defense roles to include the period when endogenous retroviruses are still infectious. DOI: http://dx.doi.org/10.7554/eLife.24695.001 PMID:28384097

Transgenerational effect of the endocrine disruptor vinclozolin on male spermatogenesis.

PubMed

Anway, Matthew D; Memon, Mushtaq A; Uzumcu, Mehmet; Skinner, Michael K

2006-01-01

The current study was designed to examine the actions of a model endocrine disruptor on embryonic testis development and male fertility. Pregnant rats (F0) that received a transient embryonic exposure to an environmental endocrine disruptor, vinclozolin, had male offspring (F1) with reduced spermatogenic capacity. The reduced spermatogenetic capacity observed in the F1 male offspring was transmitted to the subsequent generations (F2-F4). The administration of vinclozolin, an androgen receptor antagonist, at 100 mg/kg/day from embryonic day 8-14 (E8-E14) of pregnancy to only the F0 dam resulted in a transgenerational phenotype in the subsequent male offspring in the F1-F4 generations. The litter size and male/female sex ratios were similar in controls and the vinclozolin generations. The average testes/body weight index of the postnatal day 60 (P60) males was not significantly different in the vinclozolin-treated generations compared to the controls. However, the testicular spermatid number, as well as the epididymal sperm number and motility, were significantly reduced in the vinclozolin generations compared to the control animals. Postnatal day 20 (P20) testis from the vinclozolin F2 generation had no morphological abnormalities, but did have an increase in spermatogenic cell apoptosis. Although the P60 testis morphology was predominantly normal, the germ cell apoptosis was significantly increased in the testes cross sections of animals from the vinclozolin generations. The increase in apoptosis was stage-specific in the testis, with tubules at stages IX-XIV having the highest increase in apoptotic germ cells. The tubules at stages I-V also had an increase in apoptotic germ cells compared to the control samples, but tubules at stages VI-VIII had no increase in apoptotic germ cells. An outcross of a vinclozolin generation male with a wild-type female demonstrated that the reduced spermatogenic cell phenotype was transmitted through the male germ line. An outcross with a vinclozolin generation female with a wild-type male had no phenotype. A similar phenotype was observed in outbred Sprague Dawley and inbred Fisher rat strains. Observations demonstrate that a transient exposure at the time of male sex determination to the antiandrogenic endocrine disruptor vinclozolin can induce an apparent epigenetic transgenerational phenotype with reduced spermatogenic capacity.

A review of the emerging potential therapy for neurological disorders: human embryonic stem cell therapy

PubMed Central

Shroff, Geeta; Dhanda Titus, Jyoti; Shroff, Rhea

2017-01-01

The first human embryonic stem cell (hESC) line was developed in the late nineties. hESCs are capable of proliferating indefinitely and differentiate into all the three embryonic germ layers. Further, the differentiation of hESC lines into neural precursor cells and neurons, astrocytes and oligodendrocytes showed their potential in treating several incurable neurological disorders such as spinal cord injury (SCI), cerebral palsy (CP), Parkinson’s disease (PD). In this review, we will discuss the global scenario of research and therapeutic use of hESCs in the treatment of neurological disorders. Following this, we will discuss the development of a unique hESC line, how it differs from the other available hESC lines and its use in the treatment of neurological disorders. hESCs were isolated from mixture of neuronal and non-neuronal progenitor cells in their pre progenitor state in a Good Laboratory Practices, Good Tissue Practices and Good Manufacturing Practices compliant laboratory. Blastomere cells have served as a source to derive the hESCs and the xeno-free culture was demonstrated to be more safe and effective in clinical therapeutic application of hESCs. All the patients showed a remarkable improvement in their conditions and no serious adverse events were reported. This study concluded that hESC lines could be scalable and used in the treatment of various neurological disorders such as SCI, CP, and PD. PMID:28533935

The Xenopus Maternal-to-Zygotic Transition from the Perspective of the Germline.

PubMed

Yang, Jing; Aguero, Tristan; King, Mary Lou

2015-01-01

In Xenopus, the germline is specified by the inheritance of germ-plasm components synthesized at the beginning of oogenesis. Only the cells in the early embryo that receive germ plasm, the primordial germ cells (PGCs), are competent to give rise to the gametes. Thus, germ-plasm components continue the totipotent potential exhibited by the oocyte into the developing embryo at a time when most cells are preprogrammed for somatic differentiation as dictated by localized maternal determinants. When zygotic transcription begins at the mid-blastula transition, the maternally set program for somatic differentiation is realized. At this time, genetic control is ceded to the zygotic genome, and developmental potential gradually becomes more restricted within the primary germ layers. PGCs are a notable exception to this paradigm and remain transcriptionally silent until the late gastrula. How the germ-cell lineage retains full potential while somatic cells become fate restricted is a tale of translational repression, selective degradation of somatic maternal determinants, and delayed activation of zygotic transcription. © 2015 Elsevier Inc. All rights reserved.

Development of Strategies to Increase Enrollment in Clinical Trials for Children With Cancer

ClinicalTrials.gov

2014-02-12

Brain and Central Nervous System Tumors; Childhood Germ Cell Tumor; Extragonadal Germ Cell Tumor; Leukemia; Liver Cancer; Lymphoma; Neuroblastoma; Ovarian Cancer; Psychosocial Effects of Cancer and Its Treatment; Sarcoma; Unspecified Childhood Solid Tumor, Protocol Specific

Why are hematopoietic stem cells so 'sexy'? on a search for developmental explanation.

PubMed

Ratajczak, M Z

2017-08-01

Evidence has accumulated that normal human and murine hematopoietic stem cells express several functional pituitary and gonadal sex hormones, and that, in fact, some sex hormones, such as androgens, have been employed for many years to stimulate hematopoiesis in patients with bone marrow aplasia. Interestingly, sex hormone receptors are also expressed by leukemic cell lines and blasts. In this review, I will discuss the emerging question of why hematopoietic cells express these receptors. A tempting hypothetical explanation for this phenomenon is that hematopoietic stem cells are related to subpopulation of migrating primordial germ cells. To support of this notion, the anatomical sites of origin of primitive and definitive hematopoiesis during embryonic development are tightly connected with the migratory route of primordial germ cells: from the proximal epiblast to the extraembryonic endoderm at the bottom of the yolk sac and then back to the embryo proper via the primitive streak to the aorta-gonado-mesonephros (AGM) region on the way to the genital ridges. The migration of these cells overlaps with the emergence of primitive hematopoiesis in the blood islands at the bottom of the yolk sac, and definitive hematopoiesis that occurs in hemogenic endothelium in the embryonic dorsal aorta in AGM region.

Structure of Drosophila Oskar reveals a novel RNA binding protein

PubMed Central

Yang, Na; Yu, Zhenyu; Hu, Menglong; Wang, Mingzhu; Lehmann, Ruth; Xu, Rui-Ming

2015-01-01

Oskar (Osk) protein plays critical roles during Drosophila germ cell development, yet its functions in germ-line formation and body patterning remain poorly understood. This situation contrasts sharply with the vast knowledge about the function and mechanism of osk mRNA localization. Osk is predicted to have an N-terminal LOTUS domain (Osk-N), which has been suggested to bind RNA, and a C-terminal hydrolase-like domain (Osk-C) of unknown function. Here, we report the crystal structures of Osk-N and Osk-C. Osk-N shows a homodimer of winged-helix–fold modules, but without detectable RNA-binding activity. Osk-C has a lipase-fold structure but lacks critical catalytic residues at the putative active site. Surprisingly, we found that Osk-C binds the 3′UTRs of osk and nanos mRNA in vitro. Mutational studies identified a region of Osk-C important for mRNA binding. These results suggest possible functions of Osk in the regulation of stability, regulation of translation, and localization of relevant mRNAs through direct interaction with their 3′UTRs, and provide structural insights into a novel protein–RNA interaction motif involving a hydrolase-related domain. PMID:26324911

Poly(ADP-Ribosyl)ation of hnRNP A1 Protein Controls Translational Repression in Drosophila

PubMed Central

Ji, Yingbiao

2016-01-01

Poly(ADP-ribosyl)ation of heterogeneous nuclear ribonucleoproteins (hnRNPs) regulates the posttranscriptional fate of RNA during development. Drosophila hnRNP A1, Hrp38, is required for germ line stem cell maintenance and oocyte localization. The mRNA targets regulated by Hrp38 are mostly unknown. We identified 428 Hrp38-associated gene transcripts in the fly ovary, including mRNA of the translational repressor Nanos. We found that Hrp38 binds to the 3′ untranslated region (UTR) of Nanos mRNA, which contains a translation control element. We have demonstrated that translation of the luciferase reporter bearing the Nanos 3′ UTR is enhanced by dsRNA-mediated Hrp38 knockdown as well as by mutating potential Hrp38-binding sites. Our data show that poly(ADP-ribosyl)ation inhibits Hrp38 binding to the Nanos 3′ UTR, increasing the translation in vivo and in vitro. hrp38 and Parg null mutants showed an increased ectopic Nanos translation early in the embryo. We conclude that Hrp38 represses Nanos translation, whereas its poly(ADP-ribosyl)ation relieves the repression effect, allowing restricted Nanos expression in the posterior germ plasm during oogenesis and early embryogenesis. PMID:27402862

Site-directed Mutagenesis Reveals Regions Implicated in the Stability and Fiber Formation of Human λ3r Light Chains

DOE PAGES

Villalba, Miryam I.; Canul-Tec, Juan C.; Luna-Martínez, Oscar D.; ...

2014-12-11

Light chain amyloidosis (AL) is a disease that affects vital organs by the fibrillar aggregation of monoclonal light chains. λ3r germ line is significantly implicated in this disease. In this paper, we contrasted the thermodynamic stability and aggregation propensity of 3mJL2 (nonamyloidogenic) and 3rJL2 (amyloidogenic) λ3 germ lines. Because of an inherent limitation (extremely low expression), Cys at position 34 of the 3r germ line was replaced by Tyr reaching a good expression yield. A second substitution (W91A) was introduced in 3r to obtain a better template to incorporate additional mutations. Although the single mutant (C34Y) was not fibrillogenic, themore » second mutation located at CDR3 (W91A) induced fibrillogenesis. We propose, for the first time, that CDR3 (position 91) affects the stability and fiber formation of human λ3r light chains. Using the double mutant (3rJL2/YA) as template, other variants were constructed to evaluate the importance of those substitutions into the stability and aggregation propensity of λ3 light chains. A change in position 7 (P7D) boosted 3rJL2/YA fibrillogenic properties. Modification of position 48 (I48M) partially reverted 3rJL2/YA fibril aggregation. Finally, changes at positions 8 (P8S) or 40 (P40S) completely reverted fibril formation. These results confirm the influential roles of N-terminal region (positions 7 and 8) and the loop 40–60 (positions 40 and 48) on AL. X-ray crystallography revealed that the three-dimensional topology of the single and double λ3r mutants was not significantly altered. Finally, this mutagenic approach helped to identify key regions implicated in λ3 AL.« less

Surgery and Combination Chemotherapy in Treating Children With Extracranial Germ Cell Tumors

ClinicalTrials.gov

2017-12-07

Childhood Embryonal Tumor; Childhood Extracranial Germ Cell Tumor; Childhood Extragonadal Germ Cell Tumor; Childhood Malignant Ovarian Germ Cell Tumor; Childhood Malignant Testicular Germ Cell Tumor; Childhood Teratoma; Ovarian Embryonal Carcinoma; Ovarian Yolk Sac Tumor; Stage II Malignant Testicular Germ Cell Tumor; Stage IIA Ovarian Germ Cell Tumor; Stage IIB Ovarian Germ Cell Tumor; Stage IIC Ovarian Germ Cell Tumor; Stage III Malignant Testicular Germ Cell Tumor; Stage IIIA Ovarian Germ Cell Tumor; Stage IIIB Ovarian Germ Cell Tumor; Stage IIIC Ovarian Germ Cell Tumor; Testicular Choriocarcinoma and Yolk Sac Tumor; Testicular Embryonal Carcinoma

Transplantation of spermatogonial stem cells isolated from leukemic mice restores fertility without inducing leukemia

PubMed Central

Fujita, Kazutoshi; Ohta, Hiroshi; Tsujimura, Akira; Takao, Tetsuya; Miyagawa, Yasushi; Takada, Shingo; Matsumiya, Kiyomi; Wakayama, Teruhiko; Okuyama, Akihiko

2005-01-01

More than 70% of patients survive childhood leukemia, but chemotherapy and radiation therapy cause irreversible impairment of spermatogenesis. Although autotransplantation of germ cells holds promise for restoring fertility, contamination by leukemic cells may induce relapse. In this study, we isolated germ cells from leukemic mice by FACS sorting. The cell population in the high forward-scatter and low side-scatter regions of dissociated testicular cells from leukemic mice were analyzed by staining for MHC class I heavy chain (H-2Kb/H-2Db) and for CD45. Cells that did not stain positively for H-2Kb/H-2Db and CD45 were sorted as the germ cell–enriched fraction. The sorted germ cell–enriched fractions were transplanted into the testes of recipient mice exposed to alkylating agents. Transplanted germ cells colonized, and recipient mice survived. Normal progeny were produced by intracytoplasmic injection of sperm obtained from recipient testes. When unsorted germ cells from leukemic mice were transplanted into recipient testes, all recipient mice developed leukemia. The successful birth of offspring from recipient mice without transmission of leukemia to the recipients indicates the potential of autotransplantation of germ cells sorted by FACS to treat infertility secondary to anticancer treatment for childhood leukemia. PMID:15965502

Inducible Sterilization of Zebrafish by Disruption of Primordial Germ Cell Migration

PubMed Central

Wong, Ten-Tsao; Collodi, Paul

2013-01-01

During zebrafish development, a gradient of stromal-derived factor 1a (Sdf1a) provides the directional cue that guides the migration of the primordial germ cells (PGCs) to the gonadal tissue. Here we describe a method to produce large numbers of infertile fish by inducing ubiquitous expression of Sdf1a in zebrafish embryos resulting in disruption of the normal PGC migration pattern. A transgenic line of zebrafish, Tg(hsp70:sdf1a-nanos3, EGFP), was generated that expresses Sdf1a under the control of the heat-shock protein 70 (hsp70) promoter and nanos3 3?UTR. To better visualize the PGCs, the Tg(hsp70:sdf1a-nanos3, EGFP) fish were crossed with another transgenic line, Tg(kop:DsRed-nanos3), that expresses DsRed driven by the PGC-specific kop promoter. Heat treatment of the transgenic embryos caused an induction of Sdf1a expression throughout the embryo resulting in the disruption of their normal migration. Optimal embryo survival and disruption of PGC migration was achieved when transgenic embryos at the 4- to 8-cell stage were incubated at 34.5°C for 18 hours. Under these conditions, disruption of PGC migration was observed in 100% of the embryos. Sixty-four adult fish were developed from three separate batches of heat-treated embryos and all were found to be infertile males. When each male was paired with a wild-type female, only unfertilized eggs were produced and histological examination revealed that each of the adult male fish possessed severely under-developed gonads that lacked gametes. The results demonstrate that inducible Sdf1a expression is an efficient and reliable strategy to produce infertile fish. This approach makes it convenient to generate large numbers of infertile adult fish while also providing the capability to maintain a fertile brood stock. PMID:23826390

The mammalian Doublesex homolog DMRT1 is a transcriptional gatekeeper that controls the mitosis versus meiosis decision in male germ cells

PubMed Central

Matson, Clinton K.; Murphy, Mark W.; Griswold, Michael D.; Yoshida, Shosei; Bardwell, Vivian J.; Zarkower, David

2010-01-01

Summary The switch from mitosis to meiosis is a unique feature of germ cell development. In mammals, meiotic initiation requires retinoic acid (RA), which activates meiotic inducers including Stra8, but how the switch to meiosis is controlled in male germ cells (spermatogonia) remains poorly understood. Here we examine the role of the Doublesex-related transcription factor DMRT1 in adult spermatogenesis using conditional gene targeting in the mouse. Loss of Dmrt1 causes spermatogonia to precociously exit the spermatogonial program and enter meiosis. Dmrt1 therefore determines whether male germ cells undergo mitosis and spermatogonial differentiation or meiosis. Loss of Dmrt1 in spermatogonia also disrupts cyclical gene expression in Sertoli cells. DMRT1 acts in spermatogonia to restrict RA responsiveness, directly repress Stra8 transcription, and activate transcription of the spermatogonial differentiation factor Sohlh1, thereby preventing meiosis and promoting spermatogonial development. By coordinating spermatogonial development and mitotic amplification with meiosis, DMRT1 allows abundant, continuous production of sperm. PMID:20951351

Utilizing protein-lean coproducts from corn containing recombinant pharmaceutical proteins for ethanol production.

PubMed

Paraman, Ilankovan; Moeller, Lorena; Scott, M Paul; Wang, Kan; Glatz, Charles E; Johnson, Lawrence A

2010-10-13

Protein-lean fractions of corn (maize) containing recombinant (r) pharmaceutical proteins were evaluated as a potential feedstock to produce fuel ethanol. The levels of residual r-proteins in the coproduct, distillers dry grains with solubles (DDGS), were determined. Transgenic corn lines containing recombinant green fluorescence protein (r-GFP) and a recombinant subunit vaccine of Escherichia coli enterotoxin (r-LTB), primarily expressed in endosperm, and another two corn lines containing recombinant human collagen (r-CIα1) and r-GFP, primarily expressed in germ, were used as model systems. The kernels were either ground and used for fermentation or dry fractionated to recover germ-rich fractions prior to grinding for fermentation. The finished beers of whole ground kernels and r-protein-spent endosperm solids contained 127-139 and 138-155 g/L ethanol concentrations, respectively. The ethanol levels did not differ among transgenic and normal corn feedstocks, indicating the residual r-proteins did not negatively affect ethanol production. r-Protein extraction and germ removal also did not negatively affect fermentation of the remaining mass. Most r-proteins were inactivated during the mashing process used to prepare corn for fermentation. No functionally active r-GFP or r-LTB proteins were found after fermentation of the r-protein-spent solids; however, a small quantity of residual r-CIα1 was detected in DDGS, indicating that the safety of DDGS produced from transgenic grain for r-protein production needs to be evaluated for each event. Protease treatment during fermentation completely hydrolyzed the residual r-CIα1, and no residual r-proteins were detectable in DDGS.

Dramatically accelerated growth and extraordinary gigantism of transgenic mud loach Misgurnus mizolepis.

PubMed

Nam, Y K; Noh, J K; Cho, Y S; Cho, H J; Cho, K N; Kim, C G; Kim, D S

2001-08-01

Transgenic mud loaches (Misgurnus mizolepis), in which the entire transgene originated from the same species, have been generated by microinjecting the mud loach growth hormone (mlGH) gene fused to the mud loach beta-actin promoter. Out of 4,100 eggs injected, 7.5% fish derived from the injected eggs showed dramatically accelerated growth, with a maximum of 35-fold faster growth than their non-transgenic siblings. Many fast-growing transgenic individuals showed extraordinary gigantism: their body weight and total length (largest fish attained to 413 g and 41.5 cm) were larger and longer than even those of 12-year-old normal broodstock (maximum size reached to 89 g and 28 cm). Of 46 transgenic founders tested, 30 individuals transmitted the transgene to next generation with a wide range of germ-line transmission frequencies ranging from 2% to 33%. The growth performance of the subsequent generation (F1) was also dramatically accelerated up to 35-fold, although the levels of enhanced growth were variable among transgenic lines. Three transgenic germ-lines up to F4 were established, showing the expected Mendelian inheritance of the transgene. Expression of GH mRNA in many tissues was detected by RT-PCR analyses. The time required to attain marketable size (10 g) in these transgenic lines was only 30-50 days after fertilization, while at least 6 months in non-transgenic fish. Besides growth enhancement, significantly improved feed-conversion efficiency up to 1.9-fold was also observed.

Recent developments in testicular germ cell tumor research.

PubMed

van de Geijn, Gert-Jan M; Hersmus, Remko; Looijenga, Leendert H J

2009-03-01

Testicular germ cell tumors of adolescents and adults (TGCTs; the so-called type II variant) are the most frequent malignancies found in Caucasian males between 20 and 40 years of age. The incidence has increased over the last decades. TGCTs are divided into seminomas and nonseminomas, the latter consisting of the subgroups embryonal carcinoma, yolk-sac tumor, teratoma, and choriocarcinoma. The pathogenesis starts in utero, involving primordial germ cells/gonocytes that are blocked in their differentiation, and develops via the precursor lesion carcinoma in situ toward invasiveness. TGCTs are totipotent and can be considered as stem cell tumors. The developmental capacity of their cell of origin, the primordial germ cells/gonocyte, is demonstrated by the different tumor histologies of the invasive TGCTs. Seminoma represents the germ cell lineage, and embryonal carcinoma is the undifferentiated component, being the stem cell population of the nonseminomas. Somatic differentiation is seen in the teratomas (all lineages), whereas yolk-sac tumors and choriocarcinoma represent extra-embryonal differentiation. Seminomas are highly sensitive to irradiation and (DNA damaging) chemotherapy, whereas most nonseminomatous elements are less susceptible to radiation, although still sensitive to chemotherapy, with the exception of teratoma. To allow early diagnosis and follow up, appropriate markers are mandatory to discriminate between the different subgroups. In this review, a summary will be given related to several recent developments in TGCT research, especially selected because of their putative clinical impact.

Proteolytic degradation of heat shock protein A2 occurs in response to oxidative stress in male germ cells of the mouse.

PubMed

Bromfield, Elizabeth G; Aitken, R John; McLaughlin, Eileen A; Nixon, Brett

2017-02-10

Does oxidative stress compromise the protein expression of heat shock protein A2 (HSPA2) in the developing germ cells of the mouse testis? Oxidative stress leads to the modification of HSPA2 by the lipid aldehyde 4-hydroxynonenal (4HNE) and initiates its degradation via the ubiquitin-proteasome system. Previous work has revealed a deficiency in HSPA2 protein expression within the spermatozoa of infertile men that have failed fertilization in a clinical setting. While the biological basis of this reduction in HSPA2 remains to be established, we have recently shown that the HSPA2 expressed in the spermatozoa of normozoospermic individuals is highly susceptible to adduction, a form of post-translational modification, by the lipid aldehyde 4HNE that has been causally linked to the degradation of its substrates. This modification of HSPA2 by 4HNE adduction dramatically reduced human sperm-egg interaction in vitro. Moreover, studies in a mouse model offer compelling evidence that the co-chaperone BCL2-associated athanogene 6 (BAG6) plays a key role in regulating the stability of HSPA2 in the testis, by preventing its ubiquitination and subsequent proteolytic degradation. Dose-dependent studies were used to establish a 4HNE-treatment regime for primary culture(s) of male mouse germ cells. The influence of 4HNE on HSPA2 protein stability was subsequently assessed in treated germ cells. Additionally, sperm lysates from infertile patients with established zona pellucida recognition defects were examined for the presence of 4HNE and ubiquitin adducts. A minimum of three biological replicates were performed to test statistical significance. Oxidative stress was induced in pachytene spermatocytes and round spermatids isolated from the mouse testis, as well as a GC-2 cell line, using 50-200 µM 4HNE or hydrogen peroxide (H2O2), and the expression of HSPA2 was monitored via immunocytochemistry and immunoblotting approaches. Using the GC-2 cell line as a model, the ubiquitination and degradation of HSPA2 was assessed using immunoprecipitation techniques and pharmacological inhibition of proteasomal and lysosomal degradation pathways. Finally, the interaction between BAG6 and HSPA2 was examined in response to 4HNE exposure via proximity ligation assays. HSPA2 protein levels were significantly reduced compared with controls after 4HNE treatment of round spermatids (P < 0.01) and GC-2 cells (P < 0.001) but not pachytene spermatocytes. Using GC-2 cells as a model, HSPA2 was shown to be both adducted by 4HNE and targeted for ubiquitination in response to cellular oxidative stress. Inhibition of the proteasome with MG132 prevented HSPA2 degradation after 4HNE treatment indicating that the degradation of HSPA2 is likely to occur via a proteasomal pathway. Moreover, our assessment of proteasome activity provided evidence that 4HNE treatment can significantly increase the proteasome activity of GC-2 cells (P < 0.05 versus control). Finally, 4HNE exposure to GC-2 cells resulted in the dissociation of HSPA2 from its regulatory co-chaperone BAG6, a key mediator of HSPA2 stability in male germ cells. While these experiments were performed using a mouse germ cell-model system, our analyses of patient sperm lysate imply that these mechanisms are conserved between mouse and human germ cells. This study suggests a causative link between non-enzymatic post-translational modifications and the relative levels of HSPA2 in the spermatozoa of a specific sub-class of infertile males. In doing so, this work enhances our understanding of failed sperm-egg recognition and may assist in the development of targeted antioxidant-based approaches for ameliorating the production of cytotoxic lipid aldehydes in the testis in an attempt to prevent this form of infertility. Not applicable. This work was supported by the National Health and Medical Research Council of Australia (APP1101953). The authors have no competing interests to declare. © The Author 2017. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Declaring the Existence of Human Germ-Cell Mutagens

EPA Science Inventory

After more than 80 years of searching for human germ-cell mutagens, I think that sufficient evidence already exists for a number of agents to be so considered, and definitive confirmation seems imminent due to the application ofrecently developed genomic techniques. In preparatio...

bmp15l, figla, smc1bl, and larp6l are preferentially expressed in germ cells in Atlantic salmon (Salmo salar L.).

PubMed

Kleppe, Lene; Edvardsen, Rolf Brudvik; Furmanek, Tomasz; Andersson, Eva; Juanchich, Amélie; Wargelius, Anna

2017-01-01

Atlantic salmon is a valuable commercial aquaculture species that would benefit economically and environmentally by controlling precocious puberty and preventing escapees from reproducing with wild populations. One solution to both these challenges is the production of sterile individuals by inhibiting the formation of germ cells, but achieving this requires more information on the specific factors that control germ cell formation. Here, we identified and characterized novel factors that are preferentially expressed in Atlantic salmon germ cells by screening for gonad-specific genes using available adult multi-tissue transcriptomes. We excluded genes with expression in tissues other than gonads based on quantity of reads, and then a subset of genes was selected for verification in a multi-tissue PCR screen. Four gonad-specific genes (bmp15l, figla, smc1bl, and larp6l) were chosen for further characterization, namely: germ cell specificity, investigated by comparing mRNA abundance in wild-type and germ cell-free gonads by quantitative real-time PCR, and cellular location, visualized by in situ hybridization. All four genes were expressed in both testis and ovary, and preferentially within the germ cells of both sexes. These genes may be essential players in salmon germ cell development, and could be important for future studies aiming to understand and control reproduction. Mol. Reprod. Dev. 84: 76-87, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

DNA methyltransferase-3 like protein expression in various histological types of testicular germ cell tumor.

PubMed

Matsuoka, Taeko; Kawai, Koji; Ando, Satoshi; Sugita, Shintaro; Kandori, Shuya; Kojima, Takahiro; Miyazaki, Jun; Nishiyama, Hiroyuki

2016-05-01

DNA methyltransferase 3-like plays an important role in germ cell development. The aim of this study was to analyse the DNA methyltransferase 3-like protein expression in testicular germ cell tumors. The immunohistochemical expression of DNA methyltransferase 3-like was examined in 86 testicular germ cell tumor specimens in various clinical settings. The association between DNA methyltransferase 3-like expression and disease stage was analyzed. DNA methyltransferase 3-like was strongly expressed in seven of the eight pure embryonal carcinomas (87.5%). Partial DNA methyltransferase 3-like expression was observed in 6 of 23 (26.1%) pure seminomas. Various degrees of DNA methyltransferase 3-like expression was observed in all four pure yolk sac tumors, of which three were prepubertal yolk sac tumors. In mixed germ cell tumors, DNA methyltransferase 3-like protein was expressed in various degrees in elements of the embryonal carcinoma (14/18, 77.8%), seminoma (4/11, 36.4%), teratoma (4/7, 57.1%) and choriocarcinoma (3/3, 100%) but not in the yolk sac tumors (0/4). When DNA methyltransferase 3-like expression was analyzed according to disease stages, it was significantly correlated with advanced seminoma rather than Stage I seminoma (46.2 vs. 0%, P = 0.019), whereas there was no significant difference in the DNA methyltransferase 3-like-positive proportion between Stage I and advanced disease in the mixed germ cell tumors. Our findings suggest that DNA methyltransferase 3-like protein may play roles not only in the development of embryonal carcinoma but also in the development of advanced pure seminoma and pure yolk sac tumor. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Surfing the wave, cycle, life history, and genes/proteins expressed by testicular germ cells. Part 2: changes in spermatid organelles associated with development of spermatozoa.

PubMed

Hermo, Louis; Pelletier, R-Marc; Cyr, Daniel G; Smith, Charles E

2010-04-01

Spermiogenesis is a long process whereby haploid spermatids derived from the meiotic divisions of spermatocytes undergo metamorphosis into spermatozoa. It is subdivided into distinct steps with 19 being identified in rats, 16 in mouse and 8 in humans. Spermiogenesis extends over 22.7 days in rats and 21.6 days in humans. In this part, we review several key events that take place during the development of spermatids from a structural and functional point of view. During early spermiogenesis, the Golgi apparatus forms the acrosome, a lysosome-like membrane bound organelle involved in fertilization. The endoplasmic reticulum undergoes several topographical and structural modifications including the formation of the radial body and annulate lamellae. The chromatoid body is fully developed and undergoes structural and functional modifications at this time. It is suspected to be involved in RNA storing and processing. The shape of the spermatid head undergoes extensive structural changes that are species-specific, and the nuclear chromatin becomes compacted to accommodate the stream-lined appearance of the sperm head. Microtubules become organized to form a curtain or manchette that associates with spermatids at specific steps of their development. It is involved in maintenance of the sperm head shape and trafficking of proteins in the spermatid cytoplasm. During spermiogenesis, many genes/proteins have been implicated in the diverse dynamic events occurring at this time of development of germ cells and the absence of some of these have been shown to result in subfertility or infertility. Copyright 2009 Wiley-Liss, Inc.

From Embryo to Adult: piRNA-Mediated Silencing throughout Germline Development in Drosophila

PubMed Central

Marie, Pauline P.; Ronsseray, Stéphane; Boivin, Antoine

2016-01-01

In metazoan germ cells, transposable element activity is repressed by small noncoding PIWI-associated RNAs (piRNAs). Numerous studies in Drosophila have elucidated the mechanism of this repression in the adult germline. However, when and how transposable element repression is established during germline development has not been addressed. Here, we show that homology-dependent trans silencing is active in female primordial germ cells from late embryogenesis through pupal stages, and that genes related to the adult piRNA pathway are required for silencing during development. In larval gonads, we detect rhino-dependent piRNAs indicating de novo biogenesis of functional piRNAs during development. Those piRNAs exhibit the molecular signature of the “ping-pong” amplification step. Moreover, we show that Heterochromatin Protein 1a is required for the production of piRNAs coming from telomeric transposable elements. Furthermore, as in adult ovaries, incomplete, bimodal, and stochastic repression resembling variegation can occur at all developmental stages. Clonal analysis indicates that the repression status established in embryonic germ cells is maintained until the adult stage, suggesting the implication of a cellular memory mechanism. Taken together, data presented here show that piRNAs and their associated proteins are epigenetic components of a continuous repression system throughout germ cell development. PMID:27932388

Chemotherapy-Induced Depletion of OCT4-Positive Cancer Stem Cells in a Mouse Model of Malignant Testicular Cancer.

PubMed

Pierpont, Timothy M; Lyndaker, Amy M; Anderson, Claire M; Jin, Qiming; Moore, Elizabeth S; Roden, Jamie L; Braxton, Alicia; Bagepalli, Lina; Kataria, Nandita; Hu, Hilary Zhaoxu; Garness, Jason; Cook, Matthew S; Capel, Blanche; Schlafer, Donald H; Southard, Teresa; Weiss, Robert S

2017-11-14

Testicular germ cell tumors (TGCTs) are among the most responsive solid cancers to conventional chemotherapy. To elucidate the underlying mechanisms, we developed a mouse TGCT model featuring germ cell-specific Kras activation and Pten inactivation. The resulting mice developed malignant, metastatic TGCTs composed of teratoma and embryonal carcinoma, the latter of which exhibited stem cell characteristics, including expression of the pluripotency factor OCT4. Consistent with epidemiological data linking human testicular cancer risk to in utero exposures, embryonic germ cells were susceptible to malignant transformation, whereas adult germ cells underwent apoptosis in response to the same oncogenic events. Treatment of tumor-bearing mice with genotoxic chemotherapy not only prolonged survival and reduced tumor size but also selectively eliminated the OCT4-positive cancer stem cells. We conclude that the chemosensitivity of TGCTs derives from the sensitivity of their cancer stem cells to DNA-damaging chemotherapy. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Role of Axumin PET Scan in Germ Cell Tumor

ClinicalTrials.gov

2018-05-01

Testis Cancer; Germ Cell Tumor; Testicular Cancer; Germ Cell Tumor of Testis; Germ Cell Tumor, Testicular, Childhood; Testicular Neoplasms; Testicular Germ Cell Tumor; Testicular Yolk Sac Tumor; Testicular Choriocarcinoma; Testicular Diseases; Germ Cell Cancer Metastatic; Germ Cell Neoplasm of Retroperitoneum; Germ Cell Cancer, Nos

How Prewriting Fits into the Writing Process.

ERIC Educational Resources Information Center

Freeman, James A.

However the initial germ of a written work arises, there usually follows a prewriting period of meditation. At this rehearsal stage in writing, the author must gain a sense of audience and grope with such variables as genre, point of view, voice, line, tone, and pattern. Many authors of fiction keep journals or notebooks as incubation places where…

Development of space-fertilized eggs and formation of primordial germ cells in the embryos of medaka fish

NASA Astrophysics Data System (ADS)

Ijiri, K.

In the second International Microgravity Laboratory (IML-2) mission in 1994, four small Japanese killifish (Medaka, Oryzias latipes) made a space travel of 15 days aboard a space shuttle. These four adult Medaka fish successfully mated in space for the first time among vertebrate animals. Moreover, the eggs they laid developed normally, at least in their external appearance, hatching as fry (baby fish) in space. Fish mated and laid eggs every day during the first week. Near the end of the mission most of the eggs had a well-developed body with two pigmented eyes. In total, 43 eggs were laid (detected), out of which 8 fry hatched in space, as truly `space-originated' babies. A further 30 fry hatched within 3 days after landing. This is the normal hatching rate, compared with the ground-based data. Among the 8 space-originated fry, four were killed for histological sections, and germ cells at the gonadal region were counted for each fry. Their numbers were in the range of the germ cells of the normal control fry (ground-kept samples). Thus, as embryos developed normally in their external appearance, inside the embryos the formation of primordial germ cells took place normally in space, and their migration to the genital ridges was not hindered by microgravity. The two of the remaining space-originated fry have grown up and been creating their offspring in the laboratory. This proved that the primordial germ cells formed in space were also normal from a functional point of view. The four space-travelled adult fish re-started mating and laying eggs on the 7th day after landing and continued to do so every day afterward. Fertilization rate and hatchability of these eggs were as high as the eggs laid by the laboratory-kept fish. This fact implies that in gametogenesis of adult fish, there are no specific stages of germ cells extremely susceptible to microgravity.

Flexible adaptation of male germ cells from female iPSCs of endangered Tokudaia osimensis.

PubMed

Honda, Arata; Choijookhuu, Narantsog; Izu, Haruna; Kawano, Yoshihiro; Inokuchi, Mizuho; Honsho, Kimiko; Lee, Ah-Reum; Nabekura, Hiroki; Ohta, Hiroshi; Tsukiyama, Tomoyuki; Ohinata, Yasuhide; Kuroiwa, Asato; Hishikawa, Yoshitaka; Saitou, Mitinori; Jogahara, Takamichi; Koshimoto, Chihiro

2017-05-01

In mammals, the Y chromosome strictly influences the maintenance of male germ cells. Almost all mammalian species require genetic contributors to generate testes. An endangered species, Tokudaia osimensis , has a unique sex chromosome composition XO/XO, and genetic differences between males and females have not been confirmed. Although a distinctive sex-determining mechanism may exist in T. osimensis , it has been difficult to examine thoroughly in this rare animal species. To elucidate the discriminative sex-determining mechanism in T. osimensis and to find a strategy to prevent its possible extinction, we have established induced pluripotent stem cells (iPSCs) and derived interspecific chimeras using mice as the hosts and recipients. Generated iPSCs are considered to be in the so-called "true naïve" state, and T. osimensis iPSCs may contribute as interspecific chimeras to several different tissues and cells in live animals. Surprisingly, female T. osimensis iPSCs not only contributed to the female germ line in the interspecific mouse ovary but also differentiated into spermatocytes and spermatids that survived in the adult interspecific mouse testes. Thus, T. osimensis cells have high sexual plasticity through which female somatic cells can be converted to male germline cells. These findings suggest flexibility in T. osimensis cells, which can adapt their germ cell sex to the gonadal niche. The probable reduction of the extinction risk of an endangered species through the use of iPSCs is indicated by this study.

Flexible adaptation of male germ cells from female iPSCs of endangered Tokudaia osimensis

PubMed Central

Honda, Arata; Choijookhuu, Narantsog; Izu, Haruna; Kawano, Yoshihiro; Inokuchi, Mizuho; Honsho, Kimiko; Lee, Ah-Reum; Nabekura, Hiroki; Ohta, Hiroshi; Tsukiyama, Tomoyuki; Ohinata, Yasuhide; Kuroiwa, Asato; Hishikawa, Yoshitaka; Saitou, Mitinori; Jogahara, Takamichi; Koshimoto, Chihiro

2017-01-01

In mammals, the Y chromosome strictly influences the maintenance of male germ cells. Almost all mammalian species require genetic contributors to generate testes. An endangered species, Tokudaia osimensis, has a unique sex chromosome composition XO/XO, and genetic differences between males and females have not been confirmed. Although a distinctive sex-determining mechanism may exist in T. osimensis, it has been difficult to examine thoroughly in this rare animal species. To elucidate the discriminative sex-determining mechanism in T. osimensis and to find a strategy to prevent its possible extinction, we have established induced pluripotent stem cells (iPSCs) and derived interspecific chimeras using mice as the hosts and recipients. Generated iPSCs are considered to be in the so-called “true naïve” state, and T. osimensis iPSCs may contribute as interspecific chimeras to several different tissues and cells in live animals. Surprisingly, female T. osimensis iPSCs not only contributed to the female germ line in the interspecific mouse ovary but also differentiated into spermatocytes and spermatids that survived in the adult interspecific mouse testes. Thus, T. osimensis cells have high sexual plasticity through which female somatic cells can be converted to male germline cells. These findings suggest flexibility in T. osimensis cells, which can adapt their germ cell sex to the gonadal niche. The probable reduction of the extinction risk of an endangered species through the use of iPSCs is indicated by this study. PMID:28508054

[Parental genome imprinting].

PubMed

Babinet, C

1993-01-01

Genetical as well as experimental embryology methods have permitted, in recent years, to uncover a very important feature of mammalian embryonic development: it has been shown that female and male genomic complements are differentially imprinted in such a way that contribution of both a maternally and a paternally derived genome are absolutely necessary for the embryo to complete its normal development. Differential genomic imprinting seems therefore to impose some new and essential kind of information to the one already contained in the genomic sequences. The differential imprinting should be imposed on the genetic material during gametogenesis and persist throughout somatic development after fertilization. It should then be erased in the germ cell line and be established again in sperm and egg genomes. The recent discovery of several mouse genes which are imprinted should permit to address the question of the molecular mechanisms of imprinting.

Eighteen-Year Cryopreservation Does Not Negatively Affect the Pluripotency of Human Embryos: Evidence from Embryonic Stem Cell Derivation

PubMed Central

Rungsiwiwut, Ruttachuk; Numchaisrika, Pranee; Ahnonkitpanit, Vichuda; Isarasena, Nipan; Virutamasen, Pramuan

2012-01-01

Abstract Human embryonic stem (hES) cells are considered to be a potential source for the therapy of human diseases, drug screening, and the study of developmental biology. In the present study, we successfully derived hES cell lines from blastocysts developed from frozen and fresh embryos. Seventeen- to eighteen-year-old frozen embryos were thawed, cultured to the blastocyst stage, and induced to form hES cells using human foreskin fibroblasts. The Chula2.hES cell line and the Chula4.hES and Chula5.hES cell lines were derived from blastocysts developed from frozen and fresh embryos, respectively. The cell lines expressed pluripotent markers, including alkaline phosphatase (AP), Oct3/4, stage-specific embryonic antigen (SSEA)-4, and tumor recognition antigen (TRA)-1-60 and TRA-1-81 as detected with immunocytochemistry. The real-time polymerase chain reaction (RT-PCR) results showed that the cell lines expressed pluripotent genes, including OCT3/4, SOX2, NANOG, UTF, LIN28, REX1, NODAL, and E-Cadherin. In addition, the telomerase activities of the cell lines were higher than in the fibroblast cells. Moreover, the cell lines differentiated into all three germ layers both in vitro and in vivo. The cell lines had distinct identities, as revealed with DNA fingerprinting, and maintained their normal karyotype after a long-term culture. This study is the first to report the successful derivation of hES cell lines in Thailand and that frozen embryos maintained their pluripotency similar to fresh embryos, as shown by the success of hES cell derivation, even after years of cryopreservation. Therefore, embryos from prolonged cryopreservation could be an alternative source for embryonic stem cell research. PMID:23514952

Linking Sister Chromatid Cohesion to Apoptosis and Aneuploidy in the Development of Breast Cancer

DTIC Science & Technology

2005-07-01

antibody. Jurkat cells were ZE in wheat germ extract was .4 Claved fd21 transfected with blank vectors (B), treated with • • incubated in the presence...nonisotopic) hRad21 in wheat germ extracts by FPLC fractions 13-20. Samples were analyzed on an SDS-6% PAGE gel followed by Western bloting with hRda2l C...in vitro translated unlabelled hRad21 in wheat germ extracts and assaying the cleavage in Rad21 immunoblots (Fig. 5C). The broad-spectrum caspase

Testicular dysgenesis syndrome and the origin of carcinoma in situ testis.

PubMed

Sonne, Si Brask; Kristensen, David Møbjerg; Novotny, Guy W; Olesen, Inge Ahlmann; Nielsen, John E; Skakkebaek, Niels E; Rajpert-De Meyts, Ewa; Leffers, Henrik

2008-04-01

Recent increases in male reproductive disorders have been linked to exposure to environmental factors leading to the testicular dysgenesis syndrome (TDS). Testicular cancer is the most severe condition in TDS and studies have shown a clear correlation between risk of testicular cancer and other components of TDS and that the geographical location of the mother during pregnancy can be a risk factor. This suggests that the dysgenesis has its origin in utero and that TDS is initiated by environmental factors, including possibly hormone-disrupting compounds that act on the mother and the developing foetus, but the genetic background may also play a role. The morphological similarity of carcinoma in situ (CIS) cells (the precursor of the majority of invasive testicular cancers) with primordial germ cells and gonocytes, and overlap in expression of protein markers suggests an origin of CIS from primordial germ cells or gonocytes. CIS cells and germ cell-derived cancers of the human type have so far not been described in any animal model of TDS, which could be caused by species differences in the development of the male gonad. Regardless of this, it is plausible that the dysgenesis, and hence the development of CIS cells, is a result of disturbed signalling between nurse cells and germ cells that allow embryonic germ cells to survive in the pre-pubertal and adult testis. The post-pubertal proliferation of CIS cells combined with aberrant signalling then leads to an accumulation of genetic changes in the CIS cells, which eventually results in the development of invasive testicular cancer in the adult.

Successful xenogeneic germ cell transplantation from Jundia catfish (Rhamdia quelen) into adult Nile tilapia (Oreochromis niloticus) testes.

PubMed

Silva, M A; Costa, G M J; Lacerda, S M S N; Brandão-Dias, P F P; Kalapothakis, E; Silva Júnior, A F; Alvarenga, E R; França, L R

2016-05-01

Fish germ cell transplantation presents several important potential applications for aquaculture, including the preservation of germplasm from endangered fish species with high genetic and commercial values. Using this technique in studies developed in our laboratory with adult male Nile tilapias (Oreochromis niloticus), all the necessary procedures were successfully established, allowing the production of functional sperm and healthy progeny approximately 2months after allogeneic transplantation. In the present study, we evaluated the viability of the adult Nile tilapia testis to generate sperm after xenogeneic transplant of germ cells from sexually mature Jundia catfish (Rhamdia quelen) that belong to a different taxonomic order. Therefore, in order to investigate at different time-periods post-transplantation, the presence and development of donor PKH26 labeled catfish germ cells were followed in the tilapia seminiferous tubules. From 7 to 20days post-transplantation, only PKH26 labeled spermatogonia were observed, whereas spermatocytes at different stages of development were found at 70days. Germ cell transplantation success and progression of spermatogenesis were indicated by the presence of labeled PKH26 spermatids and sperm on days 90 and 120 post-transplantation, respectively. Confirming the presence of the catfish genetic material in the tilapia testis, all recipient tilapias evaluated (n=8) showed the genetic markers evaluated. Therefore, we demonstrated for the first time that the adult Nile tilapia testis offers the functional conditions for development of spermatogenesis with sperm production from a fish species belonging to a different order, which provides an important new venue for aquaculture advancement. Copyright © 2016 Elsevier Inc. All rights reserved.

Identification of Germ Plasm-Associated Transcripts by Microarray Analysis of Xenopus Vegetal Cortex RNA

PubMed Central

Cuykendall, Tawny N.; Houston, Douglas W.

2011-01-01

RNA localization is a common mechanism for regulating cell structure and function. Localized RNAs in Xenopus oocytes are critical for early development, including germline specification by the germ plasm. Despite the importance of these localized RNAs, only approximately 25 have been identified and fewer are functionally characterized. Using microarrays, we identified a large set of localized RNAs from the vegetal cortex. Overall, our results indicate a minimum of 275 localized RNAs in oocytes, or 2–3% of maternal transcripts, which are in general agreement with previous findings. We further validated vegetal localization for 24 candidates and further characterized three genes expressed in the germ plasm. We identified novel germ plasm expression for reticulon 3.1, exd2 (a novel exonuclease-domain encoding gene), and a putative noncoding RNA. Further analysis of these and other localized RNAs will likely identify new functions of germ plasm and facilitate the identification of cis-acting RNA localization elements. PMID:20503379

Generation of six multiple sclerosis patient-derived induced pluripotent stem cell lines.

PubMed

Miquel-Serra, L; Duarri, A; Muñoz, Y; Kuebler, B; Aran, B; Costa, C; Martí, M; Comabella, M; Malhotra, S; Montalban, X; Veiga, A; Raya, A

2017-10-01

Multiple sclerosis (MS) is considered a chronic autoimmune disease of the central nervous system that leads to gliosis, demyelination, axonal damage and neuronal death. The MS disease aetiology is unknown, though a polymorphism of the TNFRSF1A gene, rs1800693, is known to confer an increased risk for MS. Using retroviral delivery of reprogramming transgenes, we generated six MS patient-specific iPSC lines with two distinct genotypes, CC or TT, of the polymorphism rs1800693. iPSC lines had normal karyotype, expressed pluripotency genes and differentiated into the three germ layers. These lines offer a good tool to study MS pathomechanisms and for drug testing. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Inhibition of HMG CoA reductase reveals an unexpected role for cholesterol during PGC migration in the mouse

PubMed Central

Ding, Jiaxi; Jiang, DeChen; Kurczy, Michael; Nalepka, Jennifer; Dudley, Brian; Merkel, Erin I; Porter, Forbes D; Ewing, Andrew G; Winograd, Nicholas; Burgess, James; Molyneaux, Kathleen

2008-01-01

Background Primordial germ cells (PGCs) are the embryonic precursors of the sperm and eggs. Environmental or genetic defects that alter PGC development can impair fertility or cause formation of germ cell tumors. Results We demonstrate a novel role for cholesterol during germ cell migration in mice. Cholesterol was measured in living tissue dissected from mouse embryos and was found to accumulate within the developing gonads as germ cells migrate to colonize these structures. Cholesterol synthesis was blocked in culture by inhibiting the activity of HMG CoA reductase (HMGCR) resulting in germ cell survival and migration defects. These defects were rescued by co-addition of isoprenoids and cholesterol, but neither compound alone was sufficient. In contrast, loss of the last or penultimate enzyme in cholesterol biosynthesis did not alter PGC numbers or position in vivo. However embryos that lack these enzymes do not exhibit cholesterol defects at the stage at which PGCs are migrating. This demonstrates that during gestation, the cholesterol required for PGC migration can be supplied maternally. Conclusion In the mouse, cholesterol is required for PGC survival and motility. It may act cell-autonomously by regulating clustering of growth factor receptors within PGCs or non cell-autonomously by controlling release of growth factors required for PGC guidance and survival. PMID:19117526

Exposure to Endocrine Disruptor Induces Transgenerational Epigenetic Deregulation of MicroRNAs in Primordial Germ Cells

PubMed Central

Brieño-Enríquez, Miguel A.; García-López, Jesús; Cárdenas, David B.; Guibert, Sylvain; Cleroux, Elouan; Děd, Lukas; Hourcade, Juan de Dios; Pěknicová, Jana; Weber, Michael; del Mazo, Jesús

2015-01-01

In mammals, germ cell differentiation is initiated in the Primordial Germ Cells (PGCs) during fetal development. Prenatal exposure to environmental toxicants such as endocrine disruptors may alter PGC differentiation, development of the male germline and induce transgenerational epigenetic disorders. The anti-androgenic compound vinclozolin represents a paradigmatic example of molecule causing transgenerational effects on germ cells. We performed prenatal exposure to vinclozolin in mice and analyzed the phenotypic and molecular changes in three successive generations. A reduction in the number of embryonic PGCs and increased rate of apoptotic cells along with decrease of fertility rate in adult males were observed in F1 to F3 generations. Blimp1 is a crucial regulator of PGC differentiation. We show that prenatal exposure to vinclozolin deregulates specific microRNAs in PGCs, such as miR-23b and miR-21, inducing disequilibrium in the Lin28/let-7/Blimp1 pathway in three successive generations of males. As determined by global maps of cytosine methylation, we found no evidence for prominent changes in DNA methylation in PGCs or mature sperm. Our data suggest that embryonic exposure to environmental endocrine disruptors induces transgenerational epigenetic deregulation of expression of microRNAs affecting key regulatory pathways of germ cells differentiation. PMID:25897752

Palifosfamide in Treating Patients With Recurrent Germ Cell Tumors

ClinicalTrials.gov

2015-06-11

Adult Central Nervous System Germ Cell Tumor; Adult Teratoma; Malignant Extragonadal Germ Cell Tumor; Malignant Extragonadal Non-Seminomatous Germ Cell Tumor; Extragonadal Seminoma; Recurrent Malignant Testicular Germ Cell Tumor; Recurrent Ovarian Germ Cell Tumor; Stage IV Extragonadal Non-Seminomatous Germ Cell Tumor; Stage IV Extragonadal Seminoma; Stage IV Ovarian Germ Cell Tumor

Molecular Characteristics of Malignant Ovarian Germ Cell Tumors and Comparison With Testicular Counterparts: Implications for Pathogenesis

PubMed Central

Kraggerud, Sigrid Marie; Hoei-Hansen, Christina E.; Alagaratnam, Sharmini; Skotheim, Rolf I.; Abeler, Vera M.

2013-01-01

This review focuses on the molecular characteristics and development of rare malignant ovarian germ cell tumors (mOGCTs). We provide an overview of the genomic aberrations assessed by ploidy, cytogenetic banding, and comparative genomic hybridization. We summarize and discuss the transcriptome profiles of mRNA and microRNA (miRNA), and biomarkers (DNA methylation, gene mutation, individual protein expression) for each mOGCT histological subtype. Parallels between the origin of mOGCT and their male counterpart testicular GCT (TGCT) are discussed from the perspective of germ cell development, endocrinological influences, and pathogenesis, as is the GCT origin in patients with disorders of sex development. Integrated molecular profiles of the 3 main histological subtypes, dysgerminoma (DG), yolk sac tumor (YST), and immature teratoma (IT), are presented. DGs show genomic aberrations comparable to TGCT. In contrast, the genome profiles of YST and IT are different both from each other and from DG/TGCT. Differences between DG and YST are underlined by their miRNA/mRNA expression patterns, suggesting preferential involvement of the WNT/β-catenin and TGF-β/bone morphogenetic protein signaling pathways among YSTs. Characteristic protein expression patterns are observed in DG, YST and IT. We propose that mOGCT develop through different developmental pathways, including one that is likely shared with TGCT and involves insufficient sexual differentiation of the germ cell niche. The molecular features of the mOGCTs underline their similarity to pluripotent precursor cells (primordial germ cells, PGCs) and other stem cells. This similarity combined with the process of ovary development, explain why mOGCTs present so early in life, and with greater histological complexity, than most somatic solid tumors. PMID:23575763

Effects of the Transforming Growth Factor Beta Signaling Pathway on the Differentiation of Chicken Embryonic Stem Cells into Male Germ Cells

PubMed Central

Zhang, Yani; Wang, Yingjie; Zuo, Qisheng; Li, Dong; Zhang, Wenhui; Lian, Chao; Tang, Beibei; Xiao, Tianrong; Wang, Man; Wang, Kehua

2016-01-01

Abstract The objectives of the present study were to screen for key gene and signaling pathways involved in the production of male germ cells in poultry and to investigate the effects of the transforming growth factor beta (TGF-β) signaling pathway on the differentiation of chicken embryonic stem cells (ESCs) into male germ cells. The ESCs, primordial germ cells, and spermatogonial stem cells (SSCs) were sorted using flow cytometry for RNA sequencing (RNA-seq) technology. Male chicken ESCs were induced using 40 ng/mL of bone morphogenetic protein 4 (BMP4). The effects of the TGF-β signaling pathway on the production of chicken SSCs were confirmed by morphology, quantitative real-time polymerase chain reaction, and immunocytochemistry. One hundred seventy-three key genes relevant to development, differentiation, and metabolism and 20 signaling pathways involved in cell reproduction, differentiation, and signal transduction were identified by RNA-seq. The germ cells formed agglomerates and increased in number 14 days after induction by BMP4. During the induction process, the ESCs, Nanog, and Sox2 marker gene expression levels decreased, whereas expression of the germ cell-specific genes Stra8, Dazl, integrin-α6, and c-kit increased. The results indicated that the TGF-β signaling pathway participated in the differentiation of chicken ESCs into male germ cells. PMID:27906584

Gonadogenesis and slow proliferation of germ cells in juveniles of cultured yellowfin tuna, Thunnus albacares.

PubMed

Kobayashi, Toru; Honryo, Tomoki; Agawa, Yasuo; Sawada, Yoshifumi; Tapia, Ileana; Macìas, Karla A; Cano, Amado; Scholey, Vernon P; Margulies, Daniel; Yagishita, Naoki

2015-06-01

To develop techniques for seedling production of yellowfin tuna, the behavior of primordial germ cells (PGCs) and gonadogenesis were examined at 1-30 days post hatching (dph) using morphometric analysis, histological examination, and in situ hybridization. Immediately after hatching, PGCs were located on the dorsal side of the posterior end of the rectum under the peritoneum of the larvae, and at 3 dph they came into contact with stromal cells. PGCs and stromal cells gradually moved forward from the anus prior to 5 dph. At 7-10 dph, germ cells were surrounded by stromal cells and the gonadal primordia were formed. In individuals collected at 12 dph, PGCs were detected by in situ hybridization using a vasa mRNA probe that is a germ-cell-specific detection marker. The proliferation of germ cells in the gonadal primordia began at 7-10 dph. We observed double the number of germ cells at 30 dph (22 ± 3.2 cells), compared to that at 1 dph (11 ± 2.1 cells). Therefore, based on our data and previous reports, the initial germ cell proliferation of yellowfin tuna is relatively slower than that of other fish species. Copyright © 2015 Society for Biology of Reproduction & the Institute of Animal Reproduction and Food Research of Polish Academy of Sciences in Olsztyn. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

Human induced pluripotent stem cells and male infertility: an overview of current progress and perspectives

PubMed Central

Li, Zili; Zhao, Qian; Li, Honggang; Xiong, Chengliang

2018-01-01

Abstract Recently, significant progress has been made in ART for the treatment of male infertility. However, current ART has failed to help infertile patients with non-obstructive azoospermia, unless donor sperm is used. In fact, most couples wish to have their own genetically related child. Human induced pluripotent stem cells (hiPSCs) can be generated from patients’ somatic cells and in vitro derivation of functional germ cells from patient-specific iPSCs may provide new therapeutic strategies for infertile couples. The overall developmental dynamics of human primordial germ cells are similar to that in mice, but accumulating evidence suggests that there are crucial differences between human and mouse PGC specification. Unlike mouse iPSCs (miPSCs) in naive state, hiPSCs exhibit a primed pluripotency which possess less potential for the germ cell fate. Based on research in mice, male germ cells at different stages have been derived from hiPSCs with different protocols, including spontaneous differentiation, overexpression of germ cell regulators, addition of cytokines, co-culture with gonadal cells in vitro and xeno-transplantation. The aim of this review is to summarize the current advances in derivation of male germ cells from hiPSCs and raise the perspectives of hiPSCs in medical application for male infertility, as well as in basic research for male germ cell development. PMID:29315416

Simple and efficient production of embryonic stem cell-embryo chimeras by coculture.

PubMed Central

Wood, S A; Pascoe, W S; Schmidt, C; Kemler, R; Evans, M J; Allen, N D

1993-01-01

A method for the production of embryonic stem (ES) cell-embryo chimeras was developed that involves the simple coculture of eight-cell embryos on a lawn of ES cells. After coculture, the embryos with ES cells attached are transferred to normal embryo culture medium and allowed to develop to the blastocyst stage before reimplantation into foster mothers. Although the ES cells initially attach to the outside of the embryos, they primarily colonize the inner cell mass and its derivatives. This method results in the efficient production of chimeras with high levels of chimerism including the germ line. As embryos are handled en masse and manipulative steps are minimal, this method should greatly reduce the time and effort required to produce chimeric mice. Images Fig. 1 Fig. 2 PMID:8506303

Production of medakafish chimeras from a stable embryonic stem cell line.

PubMed

Hong, Y; Winkler, C; Schartl, M

1998-03-31

Embryonic stem (ES) cell lines provide a unique tool for introducing targeted or random genetic alterations through gene replacement, insertional mutagenesis, and gene addition because they offer the possibility for in vitro selection for the desired, but extremely rare, recombinant genotypes. So far only mouse blastocyst embryos are known to have the competence to give rise to such ES cell lines. We recently have established a stable cell line (Mes1) from blastulae of the medakafish (Oryzias latipes) that shows all characteristics of mouse ES cells in vitro. Here, we demonstrate that Mes1 cells also have the competence for chimera formation; 90% of host blastulae transplanted with Mes1 cells developed into chimeric fry. This high frequency was not compromised by cryostorage or DNA transfection of the donor cells. The Mes1 cells contributed to numerous organs derived from all three germ layers and differentiated into various types of functional cells, most readily observable in pigmented chimeras. These features suggest the possibility that Mes1 cells may be a fish equivalent of mouse ES cells and that medaka can be used as another system for the application of the ES cell technology.

Production of medakafish chimeras from a stable embryonic stem cell line

PubMed Central

Hong, Yunhan; Winkler, Christoph; Schartl, Manfred

1998-01-01

Embryonic stem (ES) cell lines provide a unique tool for introducing targeted or random genetic alterations through gene replacement, insertional mutagenesis, and gene addition because they offer the possibility for in vitro selection for the desired, but extremely rare, recombinant genotypes. So far only mouse blastocyst embryos are known to have the competence to give rise to such ES cell lines. We recently have established a stable cell line (Mes1) from blastulae of the medakafish (Oryzias latipes) that shows all characteristics of mouse ES cells in vitro. Here, we demonstrate that Mes1 cells also have the competence for chimera formation; 90% of host blastulae transplanted with Mes1 cells developed into chimeric fry. This high frequency was not compromised by cryostorage or DNA transfection of the donor cells. The Mes1 cells contributed to numerous organs derived from all three germ layers and differentiated into various types of functional cells, most readily observable in pigmented chimeras. These features suggest the possibility that Mes1 cells may be a fish equivalent of mouse ES cells and that medaka can be used as another system for the application of the ES cell technology. PMID:9520425

Essential role of citron kinase in cytokinesis of spermatogenic precursors.

PubMed

Cunto, Ferdinando Di; Imarisio, Sara; Camera, Paola; Boitani, Carla; Altruda, Fiorella; Silengo, Lorenzo

2002-12-15

During spermatogenesis, the first morphological indication of spermatogonia differentiation is incomplete cytokinesis, followed by the assembly of stable intercellular cytoplasmic communications. This distinctive feature of differentiating male germ cells has been highly conserved during evolution, suggesting that regulation of the cytokinesis endgame is a crucial aspect of spermatogenesis. However, the molecular mechanisms underlying testis-specific regulation of cytokinesis are still largely unknown. Citron kinase is a myotonin-related protein acting downstream of the GTPase Rho in cytokinesis control. We previously reported that Citron kinase knockout mice are affected by a complex neurological syndrome caused by cytokinesis block and apoptosis of specific neuronal precursors. In this report we show that, in addition, these mice display a dramatic testicular impairment, with embryonic and postnatal loss of undifferentiated germ cells and complete absence of mature spermatocytes. By contrast, the ovaries of mutant females appear essentially normal. Developmental analysis revealed that the cellular depletion observed in mutant testes is caused by increased apoptosis of undifferentiated and differentiating precursors. The same cells display a severe cytokinesis defect, resulting in the production of multinucleated cells and apoptosis. Our data indicate that Citron kinase is specifically required for cytokinesis of the male germ line.

Alterations in the developing testis transcriptome following embryonic vinclozolin exposure.

PubMed

Clement, Tracy M; Savenkova, Marina I; Settles, Matthew; Anway, Matthew D; Skinner, Michael K

2010-11-01

The current study investigates the direct effects of in utero vinclozolin exposure on the developing F1 generation rat testis transcriptome. Previous studies have demonstrated that exposure to vinclozolin during embryonic gonadal sex determination induces epigenetic modifications of the germ line and transgenerational adult onset disease states. Microarray analyses were performed to compare control and vinclozolin treated testis transcriptomes at embryonic days 13, 14 and 16. A total of 576 differentially expressed genes were identified and the major cellular functions and pathways associated with these altered transcripts were examined. The sets of regulated genes at the different development periods were found to be transiently altered and distinct. Categorization by major known functions of altered genes was performed. Specific cellular process and pathway analyses suggest the involvement of Wnt and calcium signaling, vascular development and epigenetic mechanisms as potential mediators of the direct F1 generation actions of vinclozolin. Copyright © 2010 Elsevier Inc. All rights reserved.

ALTERATIONS IN THE DEVELOPING TESTIS TRANSCRIPTOME FOLLOWING EMBRYONIC VINCLOZOLIN EXPOSURE

PubMed Central

Clement, Tracy M.; Savenkova, Marina I.; Settles, Matthew; Anway, Matthew D.; Skinner, Michael K.

2010-01-01

The current study investigates the direct effects of in utero vinclozolin exposure on the developing F1 generation rat testis transcriptome. Previous studies have demonstrated that exposure to vinclozolin during embryonic gonadal sex determination induces epigenetic modifications of the germ line and transgenerational adult onset disease states. Microarray analyses were performed to compare control and vinclozolin treated testis transcriptomes at embryonic day 13, 14 and 16. A total of 576 differentially expressed genes were identified and the major cellular functions and pathways associated with these altered transcripts were examined. The sets of regulated genes at the different development periods were found to be transiently altered and distinct. Categorization by major known functions of altered genes was performed. Specific cellular process and pathway analyses suggest the involvement of Wnt and calcium signaling, vascular development and epigenetic mechanisms as potential mediators of the direct F1 generation actions of vinclozolin. PMID:20566332

Two classes of gap junction channels mediate soma-germline interactions essential for germline proliferation and gametogenesis in Caenorhabditis elegans.

PubMed

Starich, Todd A; Hall, David H; Greenstein, David

2014-11-01

In all animals examined, somatic cells of the gonad control multiple biological processes essential for germline development. Gap junction channels, composed of connexins in vertebrates and innexins in invertebrates, permit direct intercellular communication between cells and frequently form between somatic gonadal cells and germ cells. Gap junctions comprise hexameric hemichannels in apposing cells that dock to form channels for the exchange of small molecules. Here we report essential roles for two classes of gap junction channels, composed of five innexin proteins, in supporting the proliferation of germline stem cells and gametogenesis in the nematode Caenorhabditis elegans. Transmission electron microscopy of freeze-fracture replicas and fluorescence microscopy show that gap junctions between somatic cells and germ cells are more extensive than previously appreciated and are found throughout the gonad. One class of gap junctions, composed of INX-8 and INX-9 in the soma and INX-14 and INX-21 in the germ line, is required for the proliferation and differentiation of germline stem cells. Genetic epistasis experiments establish a role for these gap junction channels in germline proliferation independent of the glp-1/Notch pathway. A second class of gap junctions, composed of somatic INX-8 and INX-9 and germline INX-14 and INX-22, is required for the negative regulation of oocyte meiotic maturation. Rescue of gap junction channel formation in the stem cell niche rescues germline proliferation and uncovers a later channel requirement for embryonic viability. This analysis reveals gap junctions as a central organizing feature of many soma-germline interactions in C. elegans. Copyright © 2014 by the Genetics Society of America.

Vertebrate development: the subtle art of germ-layer specification.

PubMed

Stemple, D L

2001-10-30

Nodal signalling is essential for vertebrate germ-layer formation. How this single signal can generate such a diverse array of tissues remains a mystery and is an area of intense research. Three recent reports reveal unanticipated subtleties to the process and provide new mechanisms for generating distinct responses.

Galactic Cosmic Ray Event-Based Risk Model (GERM) Code

NASA Technical Reports Server (NTRS)

Cucinotta, Francis A.; Plante, Ianik; Ponomarev, Artem L.; Kim, Myung-Hee Y.

2013-01-01

This software describes the transport and energy deposition of the passage of galactic cosmic rays in astronaut tissues during space travel, or heavy ion beams in patients in cancer therapy. Space radiation risk is a probability distribution, and time-dependent biological events must be accounted for physical description of space radiation transport in tissues and cells. A stochastic model can calculate the probability density directly without unverified assumptions about shape of probability density function. The prior art of transport codes calculates the average flux and dose of particles behind spacecraft and tissue shielding. Because of the signaling times for activation and relaxation in the cell and tissue, transport code must describe temporal and microspatial density of functions to correlate DNA and oxidative damage with non-targeted effects of signals, bystander, etc. These are absolutely ignored or impossible in the prior art. The GERM code provides scientists data interpretation of experiments; modeling of beam line, shielding of target samples, and sample holders; and estimation of basic physical and biological outputs of their experiments. For mono-energetic ion beams, basic physical and biological properties are calculated for a selected ion type, such as kinetic energy, mass, charge number, absorbed dose, or fluence. Evaluated quantities are linear energy transfer (LET), range (R), absorption and fragmentation cross-sections, and the probability of nuclear interactions after 1 or 5 cm of water equivalent material. In addition, a set of biophysical properties is evaluated, such as the Poisson distribution for a specified cellular area, cell survival curves, and DNA damage yields per cell. Also, the GERM code calculates the radiation transport of the beam line for either a fixed number of user-specified depths or at multiple positions along the Bragg curve of the particle in a selected material. The GERM code makes the numerical estimates of basic physical and biophysical quantities of high-energy protons and heavy ions that have been studied at the NASA Space Radiation Laboratory (NSRL) for the purpose of simulating space radiation biological effects. In the first option, properties of monoenergetic beams are treated. In the second option, the transport of beams in different materials is treated. Similar biophysical properties as in the first option are evaluated for the primary ion and its secondary particles. Additional properties related to the nuclear fragmentation of the beam are evaluated. The GERM code is a computationally efficient Monte-Carlo heavy-ion-beam model. It includes accurate models of LET, range, residual energy, and straggling, and the quantum multiple scattering fragmentation (QMSGRG) nuclear database.

Stem cells to gametes: how far should we go?

PubMed

Whittaker, Peter

2007-03-01

Murine embryonic stem cells have recently been shown to be capable of differentiating in vitro into oocytes or sperm. Should these findings be duplicated using human embryonic stem cells, this would raise a number of social and ethical concerns, some specific to these particular developments, others shared with other aspects of stem cell research. This review outlines the properties of stem cells and their conversion to gametes. Concerns raised include embryo destruction, quality of gametes derived in this way, possibility for children with two male biological parents, movement towards germ line gene therapy and 'designer babies', and the future impacts on health service provisions. It is important that public discussion of some of these issues should take place.

Treatment and Clinical Outcomes of Patients with Teratoma with Somatic-Type Malignant Transformation: An International Collaboration.

PubMed

Giannatempo, Patrizia; Pond, Gregory R; Sonpavde, Guru; Albany, Costantine; Loriot, Yohann; Sweeney, Christopher J; Salvioni, Roberto; Colecchia, Maurizio; Nicolai, Nicola; Raggi, Daniele; Rice, Kevin R; Flack, Chandra K; El Mouallem, Nemer R; Feldman, Hope; Fizazi, Karim; Einhorn, Lawrence H; Foster, Richard S; Necchi, Andrea; Cary, Clint

2016-07-01

We assessed prognostic factors, treatments and outcomes in patients with teratoma with malignant transformation, a rare occurrence among germ cell tumors. Data on patients diagnosed with teratoma with malignant transformation between June 1981 and August 2014 were collected across 5 referral centers. Chemotherapy was dichotomized as based on germ cell tumor or teratoma with malignant transformation. Cox analyses were done to evaluate prognostic factors of overall survival, the primary end point. Each factor was evaluated in a univariable model. Forward stepwise selection was used to construct an optimal model. Among 320 patients the tumor primary site was gonadal in 287 (89.7%), retroperitoneal in 17 (5.3%) and mediastinal in 16 (5%). Teratoma with malignant transformation and germ cell tumor were diagnosed concurrently in 130 patients (40.6%). A total of 49 patients (16.8%) initially presented with clinical stage I. The remaining patients were at good (123 or 42.3%), intermediate (42 or 14.4%) and poor (77 or 26.5%) risk for metastasis according to IGCCCG (International Germ Cell Cancer Collaborative Group). First line chemotherapy was given for germ cell tumor in 159 patients (49.7%), chemotherapy for teratoma with malignant transformation was performed in 14 (4.4%) and only surgery was done in 147 (45.9%). Median followup was 25.1 months (IQR 5.4-63.8). Five-year overall survival was 83.4% (95% CI 61.3 to 93.5) in patients with clinical stage I and it was also worse than expected in those with metastasis. On multivariable analyses nonprimitive neuroectodermal tumor histology (overall p = 0.004), gonadal primary tumor (p = 0.005) and fewer prior chemotherapy regimens (p <0.001) were independent predictors of better overall survival. Chemotherapy was not independently prognostic. Less heavily pretreated teratoma with malignant transformation with a gonadal primary tumor and nonprimitive neuroectodermal tumor histology appears to be associated with longer overall survival. Generally, teratoma with malignant transformation had a worse prognosis than germ cell tumor. Uncertainties persist regarding optimal chemotherapy. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Dead end1 is an essential partner of NANOS2 for selective binding of target RNAs in male germ cell development.

PubMed

Suzuki, Atsushi; Niimi, Yuki; Shinmyozu, Kaori; Zhou, Zhi; Kiso, Makoto; Saga, Yumiko

2016-01-01

RNA-binding proteins (RBPs) play important roles for generating various cell types in many developmental processes, including eggs and sperms. Nanos is widely known as an evolutionarily conserved RNA-binding protein implicated in germ cell development. Mouse NANOS2 interacts directly with the CCR4-NOT (CNOT) deadenylase complex, resulting in the suppression of specific RNAs. However, the mechanisms involved in target specificity remain elusive. We show that another RBP, Dead end1 (DND1), directly interacts with NANOS2 to load unique RNAs into the CNOT complex. This interaction is mediated by the zinc finger domain of NANOS2, which is essential for its association with target RNAs. In addition, the conditional deletion of DND1 causes the disruption of male germ cell differentiation similar to that observed in Nanos2-KO mice. Thus, DND1 is an essential partner for NANOS2 that leads to the degradation of specific RNAs. We also present the first evidence that the zinc finger domain of Nanos acts as a protein-interacting domain for another RBP, providing a novel insight into Nanos-mediated germ cell development. © 2015 The Authors.

Characterization of Oct4-GFP transgenic mice as a model to study the effect of environmental estrogens on the maturation of male germ cells by using flow cytometry.

PubMed

Porro, Valentina; Pagotto, Romina; Harreguy, María Belén; Ramírez, Sofía; Crispo, Martina; Santamaría, Clarisa; Luque, Enrique H; Rodríguez, Horacio A; Bollati-Fogolín, Mariela

2015-11-01

Oct4 is involved in regulation of pluripotency during normal development and is down-regulated during formation of postnatal reservoir of germ cells. We propose thatOct4/GFP transgenic mouse, which mimics the endogenous expression pattern of Oct4, could be used as a mammalian model to study the effects of environmental estrogens on the development of male germ cells. Oct4/GFP maturation profile was assessed during postnatal days -PND- 3, 5, 7, 10, 14 and 80, using flow cytometry. Then, we exposed pregnant mothers to 17α-ethinylestradiol (EE2) from day post coitum (dpc) 5 to PND7. Percentage of Oct4/GFP-expressing cells and levels of expression of Oct4/GPF were increased in PND7 after EE2 exposure. These observations were confirmed by analysis of GFP and endogenous Oct4 protein in the seminiferous tubules and by a reduction in epididymal sperm count in adult mice. We introduced Oct4/GFP mouse together with flow cytometry as a tool to evaluate changes in male germ cells development. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Phylogenetic Origin of oskar Coincided with the Origin of Maternally Provisioned Germ Plasm and Pole Cells at the Base of the Holometabola

PubMed Central

Lynch, Jeremy A.; Özüak, Orhan; Khila, Abderrahman; Abouheif, Ehab; Desplan, Claude; Roth, Siegfried

2011-01-01

The establishment of the germline is a critical, yet surprisingly evolutionarily labile, event in the development of sexually reproducing animals. In the fly Drosophila, germ cells acquire their fate early during development through the inheritance of the germ plasm, a specialized maternal cytoplasm localized at the posterior pole of the oocyte. The gene oskar (osk) is both necessary and sufficient for assembling this substance. Both maternal germ plasm and oskar are evolutionary novelties within the insects, as the germline is specified by zygotic induction in basally branching insects, and osk has until now only been detected in dipterans. In order to understand the origin of these evolutionary novelties, we used comparative genomics, parental RNAi, and gene expression analyses in multiple insect species. We have found that the origin of osk and its role in specifying the germline coincided with the innovation of maternal germ plasm and pole cells at the base of the holometabolous insects and that losses of osk are correlated with changes in germline determination strategies within the Holometabola. Our results indicate that the invention of the novel gene osk was a key innovation that allowed the transition from the ancestral late zygotic mode of germline induction to a maternally controlled establishment of the germline found in many holometabolous insect species. We propose that the ancestral role of osk was to connect an upstream network ancestrally involved in mRNA localization and translational control to a downstream regulatory network ancestrally involved in executing the germ cell program. PMID:21552321

Unraveling the proteomic profile of mice testis during the initiation of meiosis.

PubMed

Shao, Binbin; Guo, Yueshuai; Wang, Lei; Zhou, Quan; Gao, Tingting; Zheng, Bo; Zheng, Haoyu; Zhou, Tao; Zhou, Zuomin; Guo, Xuejiang; Huang, Xiaoyan; Sha, Jiahao

2015-04-29

In mice, once primordial germ cells (PGCs) are generated, they continue to proliferate and migrate to eventually reach the future gonads. They initiate sexual differentiation after their colonization of the gonads. During this process, retinoic acid (RA) induces meiosis in the female germ cells, which proceeds to the diplotene stage of meiotic prophase I, whereas the male germ cells initiate growth arrest. After birth, meiosis is initiated in mice spermatogonia by their conversion to preleptotene spermatocytes. There are evidences showing the roles of RA in the regulation of spermatogonial differentiation and meiosis initiation. However, it is still not well known on what responds to RA and how RA signaling engages meiosis. Thus, we constructed a proteomic profile of proteins associated with meiosis onset during testis development in mouse and identified 104 differentially expressed proteins (≥1.5 folds). Bioinformatic analysis showed proteins functioning in specific cell processes. The expression patterns of five selected proteins were verified via Western blot, of which we found that Tfrc gene was RA responsive, with a RA responsive element, and could be up regulated by RA in spermatogonial stem cell (SSC) line. Taken together, the results provide an important reference profile for further functional study of meiosis initiation. Spermatogenesis involves mitosis of spermatogonia, meiosis of spermatocytes and spermiogenesis, in which meiosis is a unique event to germ cells, and not in the somatic cells. Till now, the detailed molecular mechanisms of the transition from mitosis to meiosis are still not elucidated. With high-throughput proteomic technology, it is now possible to systemically identify proteins possibly involved. With TMT-6plex based quantification, we identified 104 proteins differentially between testes without meiosis (day 8.5) and those that were meiosis initiated (day 10.5). And a well-known protein essential for meiosis initiation, stra8, was identified to be differentially expressed in the study. And bioinformatic analysis and functional studies revealed several proteins regulated by retinoic acid, a chemical known to regulate the meiosis initiation. Thus, this quantitative proteomic approach can identify meiosis initiation regulating proteins, and further functional studies of these proteins will help elucidate the mechanisms of meiosis initiation. Copyright © 2015. Published by Elsevier B.V.

Human embryonic stem cell lines derived from single blastomeres of two 4-cell stage embryos

PubMed Central

Geens, Mieke; Mateizel, Ileana; Sermon, Karen; De Rycke, Martine; Spits, Claudia; Cauffman, Greet; Devroey, Paul; Tournaye, Herman; Liebaers, Inge; Van de Velde, Hilde

2009-01-01

BACKGROUND Recently, we demonstrated that single blastomeres of a 4-cell stage human embryo are able to develop into blastocysts with inner cell mass and trophectoderm. To further investigate potency at the 4-cell stage, we aimed to derive pluripotent human embryonic stem cells (hESC) from single blastomeres. METHODS Four 4-cell stage embryos were split on Day 2 of preimplantation development and the 16 blastomeres were individually cultured in sequential medium. On Day 3 or 4, the blastomere-derived embryos were plated on inactivated mouse embryonic fibroblasts (MEFs). RESULTS Ten out of sixteen blastomere-derived morulae attached to the MEFs, and two produced an outgrowth. They were mechanically passaged onto fresh MEFs as described for blastocyst ICM-derived hESC, and shown to express the typical stemness markers by immunocytochemistry and/or RT–PCR. In vivo pluripotency was confirmed by the presence of all three germ layers in the teratoma obtained after injection in immunodeficient mice. The first hESC line displays a mosaic normal/abnormal 46, XX, dup(7)(q33qter), del(18)(q23qter) karyotype. The second hESC line displays a normal 46, XY karyotype. CONCLUSION We report the successful derivation and characterization of two hESC lines from single blastomeres of four split 4-cell stage human embryos. These two hESC lines were derived from distinct embryos, proving that at least one of the 4-cell stage blastomeres is pluripotent. PMID:19633307

Multipotent adult germ-line stem cells, like other pluripotent stem cells, can be killed by cytotoxic T lymphocytes despite low expression of major histocompatibility complex class I molecules

PubMed Central

Dressel, Ralf; Guan, Kaomei; Nolte, Jessica; Elsner, Leslie; Monecke, Sebastian; Nayernia, Karim; Hasenfuss, Gerd; Engel, Wolfgang

2009-01-01

Background Multipotent adult germ-line stem cells (maGSCs) represent a new pluripotent cell type that can be derived without genetic manipulation from spermatogonial stem cells (SSCs) present in adult testis. Similarly to induced pluripotent stem cells (iPSCs), they could provide a source of cellular grafts for new transplantation therapies of a broad variety of diseases. To test whether these stem cells can be rejected by the recipients, we have analyzed whether maGSCs and iPSCs can become targets for cytotoxic T lymphocytes (CTL) or whether they are protected, as previously proposed for embryonic stem cells (ESCs). Results We have observed that maGSCs can be maintained in prolonged culture with or without leukemia inhibitory factor and/or feeder cells and still retain the capacity to form teratomas in immunodeficient recipients. They were, however, rejected in immunocompetent allogeneic recipients, and the immune response controlled teratoma growth. We analyzed the susceptibility of three maGSC lines to CTL in comparison to ESCs, iPSCs, and F9 teratocarcinoma cells. Major histocompatibility complex (MHC) class I molecules were not detectable by flow cytometry on these stem cell lines, apart from low levels on one maGSC line (maGSC Stra8 SSC5). However, using a quantitative real time PCR analysis H2K and B2m transcripts were detected in all pluripotent stem cell lines. All pluripotent stem cell lines were killed in a peptide-dependent manner by activated CTLs derived from T cell receptor transgenic OT-I mice after pulsing of the targets with the SIINFEKL peptide. Conclusion Pluripotent stem cells, including maGSCs, ESCs, and iPSCs can become targets for CTLs, even if the expression level of MHC class I molecules is below the detection limit of flow cytometry. Thus they are not protected against CTL-mediated cytotoxicity. Therefore, pluripotent cells might be rejected after transplantation by this mechanism if specific antigens are presented and if specific activated CTLs are present. Our results show that the adaptive immune system has in principle the capacity to kill pluripotent and teratoma forming stem cells. This finding might help to develop new strategies to increase the safety of future transplantations of in vitro differentiated cells by exploiting a selective immune response against contaminating undifferentiated cells. Reviewers This article was reviewed by Bhagirath Singh, Etienne Joly and Lutz Walter. PMID:19715575

[About the infection of Drosophila female germ line cells by sigma virus (author's transl)].

PubMed

Brun, G

1977-01-01

The results which have been presented by Bregliano (1973) and Bregliano et Fleuriet (1975) in this "Annales" are discussed. The author's conclusion is that there are two distinct mechanisms for contamination of the cysts of non-stabilized females (in stabilized females, all cells, including oogonial cells, are infected in carrier state by sigma). Hypotheses are discussed.

Germ-line transformation of the Queensland fruit fly, Bactrocera tryoni, using a piggyBac vector in the presence of endogenous piggyBac elements

USDA-ARS?s Scientific Manuscript database

We report the stable genetic transformation of the Queensland fruit fly Bactrocera tryoni using a piggyBac vector marked with either the fluorescent protein DsRed or EGFP.A transformation frequency of 5–10% was obtained.Inheritance of the transgenes has remained stable over eight generations despite...

LINE-1 Mediated Insertion into Poc1a (Protein of Centriole 1 A) Causes Growth Insufficiency and Male Infertility in Mice

PubMed Central

Geister, Krista A.; Brinkmeier, Michelle L.; Cheung, Leonard Y.; Wendt, Jennifer; Oatley, Melissa J.; Burgess, Daniel L.; Kozloff, Kenneth M.; Cavalcoli, James D.; Oatley, Jon M.; Camper, Sally A.

2015-01-01

Skeletal dysplasias are a common, genetically heterogeneous cause of short stature that can result from disruptions in many cellular processes. We report the identification of the lesion responsible for skeletal dysplasia and male infertility in the spontaneous, recessive mouse mutant chagun. We determined that Poc1a, encoding protein of the centriole 1a, is disrupted by the insertion of a processed Cenpw cDNA, which is flanked by target site duplications, suggestive of a LINE-1 retrotransposon-mediated event. Mutant fibroblasts have impaired cilia formation and multipolar spindles. Male infertility is caused by defective spermatogenesis early in meiosis and progressive germ cell loss. Spermatogonial stem cell transplantation studies revealed that Poc1a is essential for normal function of both Sertoli cells and germ cells. The proliferative zone of the growth plate is small and disorganized because chondrocytes fail to re-align after cell division and undergo increased apoptosis. Poc1a and several other genes associated with centrosome function can affect the skeleton and lead to skeletal dysplasias and primordial dwarfisms. This mouse mutant reveals how centrosome dysfunction contributes to defects in skeletal growth and male infertility. PMID:26496357

Immunoglobulin λ Gene Rearrangement Can Precede κ Gene Rearrangement

DOE PAGES

Berg, Jörg; Mcdowell, Mindy; Jäck, Hans-Martin; ...

1990-01-01

Imore » mmunoglobulin genes are generated during differentiation of B lymphocytes by joining gene segments. A mouse pre-B cell contains a functional immunoglobulin heavy-chain gene, but no light-chain gene. Although there is only one heavy-chain locus, there are two lightchain loci: κ and λ .t has been reported that κ loci in the germ-line configuration are never (in man) or very rarely (in the mouse) present in cells with functionally rearranged λ -chain genes. Two explanations have been proposed to explain this: (a) the ordered rearrangement theory, which postulates that light-chain gene rearrangement in the pre-B cell is first attempted at the κ locus, and that only upon failure to produce a functional κ chain is there an attempt to rearrange the λ locus; and (b) the stochastic theory, which postulates that rearrangement at the λ locus proceeds at a rate that is intrinsically much slower than that at the κ locus. We show here that λ -chain genes are generated whether or not the κ locus has lost its germ-line arrangement, a result that is compatible only with the stochastic theory.« less

Somatic diversification in the heavy chain variable region genes expressed by human autoantibodies bearing a lupus-associated nephritogenic anti-DNA idiotype

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demaison, C.; Chastagner, P.; Theze, J.

1994-01-18

Monoclonal anti-DNA antibodies bearing a lupus nephritis-associated idiotype were derived from five patients with systemic lupus erythematosus (SLE). Genes encoding their heavy (H)-chain variable (V[sub H]) regions were cloned and sequenced. When compared with their closest V[sub h] germ-line gene relatives, these sequences exhibit a number of silent (S) and replacement (R) substitutions. The ratios of R/S mutations were much higher in the complementarity-determining regions (CDRs) of the antibodies than in the framework regions. Molecular amplification of genomic V[sub H] genes and Southern hybridization with somatic CDR2-specific oligonucleotide probes showed that the configuration of the V[sub H] genes corresponding tomore » V[sub H] sequences in the nephritogenic antibodies is not present in the patient's own germ-line DNA, implying that the B-cell clones underwent somatic mutation in vivo. These findings, together with the characteristics of the diversity and junctional gene elements utilized to form the antibody, indicate that these autoantibodies have been driven through somatic selection processes reminiscent of those that govern antibody responses triggered by exogenous stimuli.« less

Detection of PIWI and piRNAs in the mitochondria of mammalian cancer cells.

PubMed

Kwon, ChangHyuk; Tak, Hyosun; Rho, Mina; Chang, Hae Ryung; Kim, Yon Hui; Kim, Kyung Tae; Balch, Curt; Lee, Eun Kyung; Nam, Seungyoon

2014-03-28

Piwi-interacting RNAs (piRNAs) are 26-31 nt small noncoding RNAs that are processed from their longer precursor transcripts by Piwi proteins. Localization of Piwi and piRNA has been reported mostly in nucleus and cytoplasm of higher eukaryotes germ-line cells, where it is believed that known piRNA sequences are located in repeat regions of nuclear genome in germ-line cells. However, localization of PIWI and piRNA in mammalian somatic cell mitochondria yet remains largely unknown. We identified 29 piRNA sequence alignments from various regions of the human mitochondrial genome. Twelve out 29 piRNA sequences matched stem-loop fragment sequences of seven distinct tRNAs. We observed their actual expression in mitochondria subcellular fractions by inspecting mitochondrial-specific small RNA-Seq datasets. Of interest, the majority of the 29 piRNAs overlapped with multiple longer transcripts (expressed sequence tags) that are unique to the human mitochondrial genome. The presence of mature piRNAs in mitochondria was detected by qRT-PCR of mitochondrial subcellular RNAs. Further validation showed detection of Piwi by colocalization using anti-Piwil1 and mitochondria organelle-specific protein antibodies. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Directed evolution of human T cell receptor CDR2 residues by phage display dramatically enhances affinity for cognate peptide-MHC without increasing apparent cross-reactivity

PubMed Central

Dunn, Steven M.; Rizkallah, Pierre J.; Baston, Emma; Mahon, Tara; Cameron, Brian; Moysey, Ruth; Gao, Feng; Sami, Malkit; Boulter, Jonathan; Li, Yi; Jakobsen, Bent K.

2006-01-01

The mammalian α/β T cell receptor (TCR) repertoire plays a pivotal role in adaptive immunity by recognizing short, processed, peptide antigens bound in the context of a highly diverse family of cell-surface major histocompatibility complexes (pMHCs). Despite the extensive TCR–MHC interaction surface, peptide-independent cross-reactivity of native TCRs is generally avoided through cell-mediated selection of molecules with low inherent affinity for MHC. Here we show that, contrary to expectations, the germ line-encoded complementarity determining regions (CDRs) of human TCRs, namely the CDR2s, which appear to contact only the MHC surface and not the bound peptide, can be engineered to yield soluble low nanomolar affinity ligands that retain a surprisingly high degree of specificity for the cognate pMHC target. Structural investigation of one such CDR2 mutant implicates shape complementarity of the mutant CDR2 contact interfaces as being a key determinant of the increased affinity. Our results suggest that manipulation of germ line CDR2 loops may provide a useful route to the production of high-affinity TCRs with therapeutic and diagnostic potential. PMID:16600963

LINE-1 Mediated Insertion into Poc1a (Protein of Centriole 1 A) Causes Growth Insufficiency and Male Infertility in Mice.

PubMed

Geister, Krista A; Brinkmeier, Michelle L; Cheung, Leonard Y; Wendt, Jennifer; Oatley, Melissa J; Burgess, Daniel L; Kozloff, Kenneth M; Cavalcoli, James D; Oatley, Jon M; Camper, Sally A

2015-10-01

Skeletal dysplasias are a common, genetically heterogeneous cause of short stature that can result from disruptions in many cellular processes. We report the identification of the lesion responsible for skeletal dysplasia and male infertility in the spontaneous, recessive mouse mutant chagun. We determined that Poc1a, encoding protein of the centriole 1a, is disrupted by the insertion of a processed Cenpw cDNA, which is flanked by target site duplications, suggestive of a LINE-1 retrotransposon-mediated event. Mutant fibroblasts have impaired cilia formation and multipolar spindles. Male infertility is caused by defective spermatogenesis early in meiosis and progressive germ cell loss. Spermatogonial stem cell transplantation studies revealed that Poc1a is essential for normal function of both Sertoli cells and germ cells. The proliferative zone of the growth plate is small and disorganized because chondrocytes fail to re-align after cell division and undergo increased apoptosis. Poc1a and several other genes associated with centrosome function can affect the skeleton and lead to skeletal dysplasias and primordial dwarfisms. This mouse mutant reveals how centrosome dysfunction contributes to defects in skeletal growth and male infertility.

Establishment of induced pluripotent stem cell (iPSC) line from 55-year old male patient with hemorrhagic Moyamoya disease.

PubMed

Cardano, Marina; Marsoner, Fabio; Marcatili, Matteo; Karnavas, Thodoris; Zasso, Jacopo; Lanterna, Luigi Andrea; Conti, Luciano

2016-11-01

Peripheral blood mononuclear cells (PBMCs) were collected from 55-year old male patient with a confirmed diagnosis of hemorrhagic Moyamoya disease (MMD). PBMCs were reprogrammed using Sendai virus particles delivering the four Yamanaka factors. A footprint-free hiPSC line was characterized by the expression of pluripotency markers and a normal karyotype. These cells were able to give rise to Embryoid Bodies and to a progeny of differentiated cells belonging to the 3 germ layers. This hiPSC line represents a suitable tool for modelling in vitro MMD disease to investigate the cellular mechanisms underlying the occurrence of this pathology. Copyright © 2016. Published by Elsevier B.V.

Dorsoventral patterning in hemichordates: insights into early chordate evolution.

PubMed

Lowe, Christopher J; Terasaki, Mark; Wu, Michael; Freeman, Robert M; Runft, Linda; Kwan, Kristen; Haigo, Saori; Aronowicz, Jochanan; Lander, Eric; Gruber, Chris; Smith, Mark; Kirschner, Marc; Gerhart, John

2006-09-01

We have compared the dorsoventral development of hemichordates and chordates to deduce the organization of their common ancestor, and hence to identify the evolutionary modifications of the chordate body axis after the lineages split. In the hemichordate embryo, genes encoding bone morphogenetic proteins (Bmp) 2/4 and 5/8, as well as several genes for modulators of Bmp activity, are expressed in a thin stripe of ectoderm on one midline, historically called "dorsal." On the opposite midline, the genes encoding Chordin and Anti-dorsalizing morphogenetic protein (Admp) are expressed. Thus, we find a Bmp-Chordin developmental axis preceding and underlying the anatomical dorsoventral axis of hemichordates, adding to the evidence from Drosophila and chordates that this axis may be at least as ancient as the first bilateral animals. Numerous genes encoding transcription factors and signaling ligands are expressed in the three germ layers of hemichordate embryos in distinct dorsoventral domains, such as pox neuro, pituitary homeobox, distalless, and tbx2/3 on the Bmp side and netrin, mnx, mox, and single-minded on the Chordin-Admp side. When we expose the embryo to excess Bmp protein, or when we deplete endogenous Bmp by small interfering RNA injections, these expression domains expand or contract, reflecting their activation or repression by Bmp, and the embryos develop as dorsalized or ventralized limit forms. Dorsoventral patterning is independent of anterior/posterior patterning, as in Drosophila but not chordates. Unlike both chordates and Drosophila, neural gene expression in hemichordates is not repressed by high Bmp levels, consistent with their development of a diffuse rather than centralized nervous system. We suggest that the common ancestor of hemichordates and chordates did not use its Bmp-Chordin axis to segregate epidermal and neural ectoderm but to pattern many other dorsoventral aspects of the germ layers, including neural cell fates within a diffuse nervous system. Accordingly, centralization was added in the chordate line by neural-epidermal segregation, mediated by the pre-existing Bmp-Chordin axis. Finally, since hemichordates develop the mouth on the non-Bmp side, like arthropods but opposite to chordates, the mouth and Bmp-Chordin axis may have rearranged in the chordate line, one relative to the other.

Dorsoventral Patterning in Hemichordates: Insights into Early Chordate Evolution

PubMed Central

Lowe, Christopher J; Terasaki, Mark; Wu, Michael; Freeman, Robert M; Runft, Linda; Kwan, Kristen; Haigo, Saori; Aronowicz, Jochanan; Lander, Eric; Gruber, Chris; Smith, Mark; Kirschner, Marc; Gerhart, John

2006-01-01

We have compared the dorsoventral development of hemichordates and chordates to deduce the organization of their common ancestor, and hence to identify the evolutionary modifications of the chordate body axis after the lineages split. In the hemichordate embryo, genes encoding bone morphogenetic proteins (Bmp) 2/4 and 5/8, as well as several genes for modulators of Bmp activity, are expressed in a thin stripe of ectoderm on one midline, historically called “dorsal.” On the opposite midline, the genes encoding Chordin and Anti-dorsalizing morphogenetic protein (Admp) are expressed. Thus, we find a Bmp-Chordin developmental axis preceding and underlying the anatomical dorsoventral axis of hemichordates, adding to the evidence from Drosophila and chordates that this axis may be at least as ancient as the first bilateral animals. Numerous genes encoding transcription factors and signaling ligands are expressed in the three germ layers of hemichordate embryos in distinct dorsoventral domains, such as pox neuro, pituitary homeobox, distalless, and tbx2/3 on the Bmp side and netrin, mnx, mox, and single-minded on the Chordin-Admp side. When we expose the embryo to excess Bmp protein, or when we deplete endogenous Bmp by small interfering RNA injections, these expression domains expand or contract, reflecting their activation or repression by Bmp, and the embryos develop as dorsalized or ventralized limit forms. Dorsoventral patterning is independent of anterior/posterior patterning, as in Drosophila but not chordates. Unlike both chordates and Drosophila, neural gene expression in hemichordates is not repressed by high Bmp levels, consistent with their development of a diffuse rather than centralized nervous system. We suggest that the common ancestor of hemichordates and chordates did not use its Bmp-Chordin axis to segregate epidermal and neural ectoderm but to pattern many other dorsoventral aspects of the germ layers, including neural cell fates within a diffuse nervous system. Accordingly, centralization was added in the chordate line by neural-epidermal segregation, mediated by the pre-existing Bmp-Chordin axis. Finally, since hemichordates develop the mouth on the non-Bmp side, like arthropods but opposite to chordates, the mouth and Bmp-Chordin axis may have rearranged in the chordate line, one relative to the other. PMID:16933975

Derivation of an induced pluripotent stem cell line (MUSIi004-A) from dermal fibroblasts of a 48-year-old spinocerebellar ataxia type 3 patient.

PubMed

Ritthaphai, Alisa; Wattanapanitch, Methichit; Pithukpakorn, Manop; Heepchantree, Worapa; Soi-Ampornkul, Rungtip; Mahaisavariya, Panchalee; Triwongwaranat, Daranporn; Pattanapanyasat, Kovit; Vatanashevanopakorn, Chinnavuth

2018-05-21

Dermal fibroblasts were obtained from a 48-year-old female patient with spinocerebellar ataxia type 3 (SCA3). Fibroblasts were reprogrammed by nucleofection with episomal plasmids, carrying L-MYC, LIN28, OCT4, SOX2, KLF4, EBNA-1 and shRNA against p53. The SCA3 patient-specific iPSC line, MUSIi004-A, was characterized by immunofluorescence staining to verify the expression of pluripotent markers. The iPSC line exhibited an ability to differentiate into three germ layers by embryoid body (EB) formation. Karyotypic analysis of the MUSIi004-A line was normal. The mutant allele was still present in the iPSC line. This iPSC line represents a useful tool for studying neurodegeneration in SCA3. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Grinding and cooking dry-mill germ to optimize aqueous enzymatic oil extraction

USDA-ARS?s Scientific Manuscript database

The many recent dry grind plants that convert corn to ethanol are potential sources of substantial amounts of corn oil. This report describes an aqueous enzymatic extraction (AEE) method to separate oil from dry-mill corn germ (DMG). The method is an extension of AEE previously developed for wet...

Cardiac metastasis from yolk sac tumor: case report and review.

PubMed

Nunes, Maria Carmo Pereira; Moreira, Daniel Ribeiro; Ferrari, Teresa Cristina Abreu

2013-01-01

Cardiac metastasis of germ cell tumors is extremely rare, particularly in females. We report a case of a 26-year-old previously healthy woman who presented with a 5-month history of abdominal pain, weight loss, fever, generalized lymphadenopathy, and acanthosis nigricans. Biopsy of cervical lymph nodes revealed a poorly differentiated neoplasm. Immunohistochemical staining was positive for alpha-fetoprotein suggesting the diagnosis of a germ cell tumor. During the investigation, the patient developed heart failure and a mass attached to the right ventricle was detected by the echocardiogram. In a few days, she developed multiple organ failure and died. Post-mortem examination revealed a malignant mixed germ cell tumor of the right ovary with extensive hematogenic and lymphatic dissemination, a polypoid mass attached to the right ventricle, emboli in the endocardial and epicardial vessels, and infiltration surrounding the coronary arteries. To the best of our knowledge this is the third report of grossly visible heart metastases from a yolk sac tumor in a female patient. A summary of all published cases of germ cell tumors with cardiac metastasis over the last 20 years is also presented.

Functional lacrimal gland regeneration by transplantation of a bioengineered organ germ

PubMed Central

Hirayama, Masatoshi; Ogawa, Miho; Oshima, Masamitsu; Sekine, Yurie; Ishida, Kentaro; Yamashita, Kentaro; Ikeda, Kazutaka; Shimmura, Shigeto; Kawakita, Tetsuya; Tsubota, Kazuo; Tsuji, Takashi

2013-01-01

The lacrimal gland has a multifaceted role in maintaining a homeostatic microenvironment for a healthy ocular surface via tear secretion. Dry-eye disease, which is caused by lacrimal gland dysfunction, is one of the most prevalent eye diseases that cause corneal epithelial damage and results in significant loss of vision and a reduction in the quality of life. Here we demonstrate orthotopic transplantation of bioengineered lacrimal gland germs into adult mice with an extra-orbital lacrimal gland defect, a mouse model that mimics the corneal epithelial damage caused by lacrimal gland dysfunction. The bioengineered lacrimal gland germs and harderian gland germs both develop in vivo and achieve sufficient physiological functionality, including tear production in response to nervous stimulation and ocular surface protection. This study demonstrates the potential for bioengineered organ replacement to functionally restore the lacrimal gland. PMID:24084941

Molecular biology of testicular germ cell tumors.

PubMed

Gonzalez-Exposito, R; Merino, M; Aguayo, C

2016-06-01

Testicular germ cell tumors (TGCTs) are the most common solid tumors in young adult men. They constitute a unique pathology because of their embryonic and germ origin and their special behavior. Genetic predisposition, environmental factors involved in their development and genetic aberrations have been under study in many works throughout the last years trying to explain the susceptibility and the transformation mechanism of TGCTs. Despite the high rate of cure in this type of tumors because its particular sensitivity to cisplatin, there are tumors resistant to chemotherapy for which it is needed to find new therapies. In the present work, it has been carried out a literature review on the most important molecular aspects involved in the onset and development of such tumors, as well as a review of the major developments regarding prognostic factors, new prognostic biomarkers and the possibility of new targeted therapies.

Dissecting Germ Cell Metabolism through Network Modeling.

PubMed

Whitmore, Leanne S; Ye, Ping

2015-01-01

Metabolic pathways are increasingly postulated to be vital in programming cell fate, including stemness, differentiation, proliferation, and apoptosis. The commitment to meiosis is a critical fate decision for mammalian germ cells, and requires a metabolic derivative of vitamin A, retinoic acid (RA). Recent evidence showed that a pulse of RA is generated in the testis of male mice thereby triggering meiotic commitment. However, enzymes and reactions that regulate this RA pulse have yet to be identified. We developed a mouse germ cell-specific metabolic network with a curated vitamin A pathway. Using this network, we implemented flux balance analysis throughout the initial wave of spermatogenesis to elucidate important reactions and enzymes for the generation and degradation of RA. Our results indicate that primary RA sources in the germ cell include RA import from the extracellular region, release of RA from binding proteins, and metabolism of retinal to RA. Further, in silico knockouts of genes and reactions in the vitamin A pathway predict that deletion of Lipe, hormone-sensitive lipase, disrupts the RA pulse thereby causing spermatogenic defects. Examination of other metabolic pathways reveals that the citric acid cycle is the most active pathway. In addition, we discover that fatty acid synthesis/oxidation are the primary energy sources in the germ cell. In summary, this study predicts enzymes, reactions, and pathways important for germ cell commitment to meiosis. These findings enhance our understanding of the metabolic control of germ cell differentiation and will help guide future experiments to improve reproductive health.

Perspectives on testicular germ cell neoplasms.

PubMed

Cheng, Liang; Lyu, Bingjian; Roth, Lawrence M

2017-01-01

Our knowledge of testicular germ cell neoplasms has progressed in the last few decades due to the description of germ cell neoplasia in situ (GCNIS) and a variety of specific forms of intratubular germ cell neoplasia, the discovery of isochromosome 12p and its importance in the development of invasiveness in germ cell tumors (GCTs), the identification of specific transcription factors for GCTs, and the recognition that a teratomatous component in mixed GCT represents terminal differentiation. Isochromosome 12p and 12p overrepresentation, collectively referred to as 12p amplification, are fundamental abnormalities that account for many types of malignant GCTs of the testis. Embryonal carcinoma is common in the testis but rare in the ovary, whereas the converse is true for mature cystic teratoma. Spermatocytic tumor occurs only in the testis; it has not been described in the ovary or extragonadal sites. The origin of ovarian mature cystic teratoma is similar to that of prepubertal-type testicular teratoma and dermoid cyst at any age in that it arises from a nontransformed germ cell, whereas postpubertal-type testicular teratoma arises from a malignant germ cell, most commonly through the intermediary of GCNIS. Somatic neoplasms, often referred to as monodermal teratomas, arise not infrequently from mature cystic teratoma of the ovary, whereas such neoplasms are rare in testicular teratoma with the exception of carcinoid. Integration of classical morphologic observations and emerging novel molecular studies will result in better understanding of the pathogenesis of GCTs and will optimize patient therapy. Copyright © 2016 Elsevier Inc. All rights reserved.

The teeth of the horse: evolution and anatomo-morphological and radiographic study of their development in the foetus.

PubMed

Soana, S; Gnudi, G; Bertoni, G

1999-12-01

The aim of this work was to study the ontogenetic process in teeth from their early appearance in the ossifying matrix of the mandible and maxilla, in different foetuses of scalar ages. Radiographic examinations of the skull and mandible hemisections were performed and the latero-medial (LM) and dorsoventral (DV) projections for the skull and mandible were analysed. A high-definition film-screen combination was used for this study. The exposure values ranged from 35 kV/6 mAs to 58 kV/10 mAs, according to the size of the skulls and their degree of ossification. The first dental germ observed was the P3, at 138-140 days of pregnancy. At 146 days, P2 and P4 dental germs were visible. At 160-168 days, the dental germ of the first deciduous incisor tooth (I1) appeared; at 180-188 days of pregnancy the germ of the second (I2), and at 224 days the germ of the third (I3), were detectable. At 275 days the dental germ of the mandibular first molar tooth (M1) appeared, while the maxillary M1, which was not visible radiographically, was represented by a jelly-like amorphous body within its alveolar cavity.

Regulation of male germ cell cycle arrest and differentiation by DND1 is modulated by genetic background

PubMed Central

Cook, Matthew S.; Munger, Steven C.; Nadeau, Joseph H.; Capel, Blanche

2011-01-01

Human germ cell tumors show a strong sensitivity to genetic background similar to Dnd1Ter/Ter mutant mice, where testicular teratomas arise only on the 129/SvJ genetic background. The introduction of the Bax mutation onto mixed background Dnd1Ter/Ter mutants, where teratomas do not typically develop, resulted in a high incidence of teratomas. However, when Dnd1Ter/Ter; Bax–/– double mutants were backcrossed to C57BL/6J, no tumors arose. Dnd1Ter/Ter germ cells show a strong downregulation of male differentiation genes including Nanos2. In susceptible strains, where teratomas initiate around E15.5-E17.5, many mutant germ cells fail to enter mitotic arrest in G0 and do not downregulate the pluripotency markers NANOG, SOX2 and OCT4. We show that DND1 directly binds a group of transcripts that encode negative regulators of the cell cycle, including p27Kip1 and p21Cip1. P27Kip1 and P21Cip1 protein are both significantly decreased in Dnd1Ter/Ter germ cells on all strain backgrounds tested, strongly suggesting that DND1 regulates mitotic arrest in male germ cells through translational regulation of cell cycle genes. Nonetheless, in C57BL/6J mutants, germ cells arrest prior to M-phase of the cell cycle and downregulate NANOG, SOX2 and OCT4. Consistent with their ability to rescue cell cycle arrest, C57BL/6J germ cells overexpress negative regulators of the cell cycle relative to 129/SvJ. This work suggests that reprogramming of pluripotency in germ cells and prevention of tumor formation requires cell cycle arrest, and that differences in the balance of cell cycle regulators between 129/SvJ and C57BL/6 might underlie differences in tumor susceptibility. PMID:21115610

Organization of cytokeratin cytoskeleton and germ plasm in the vegetal cortex of Xenopus laevis oocytes depends on coding and non-coding RNAs: Three-dimensional and ultrastructural analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kloc, Malgorzata; Bilinski, Szczepan; Dougherty, Matthew T.

2007-05-01

Recent studies discovered a novel structural role of RNA in maintaining the integrity of the mitotic spindle and cellular cytoskeleton. In Xenopus laevis, non-coding Xlsirts and coding VegT RNAs play a structural role in anchoring localized RNAs, maintaining the organization of the cytokeratin cytoskeleton and germinal granules in the oocyte vegetal cortex and in subsequent development of the germline in the embryo. We studied the ultrastructural effects of antisense oligonucleotide driven ablation of Xlsirts and VegT RNAs on the organization of the cytokeratin, germ plasm and other components of the vegetal cortex. We developed a novel method to immunolabel andmore » visualize cytokeratin at the electron microscopy level, which allowed us to reconstruct the ultrastructural organization of the cytokeratin network relative to the components of the vegetal cortex in Xenopus oocytes. The removal of Xlsirts and VegT RNAs not only disrupts the cytokeratin cytoskeleton but also has a profound transcript-specific effect on the anchoring and distribution of germ plasm islands and their germinal granules and the arrangement of yolk platelets within the vegetal cortex. We suggest that the cytokeratin cytoskeleton plays a role in anchoring of germ plasm islands within the vegetal cortex and germinal granules within the germ plasm islands.« less

Poly(ADP-Ribosyl)ation of hnRNP A1 Protein Controls Translational Repression in Drosophila.

PubMed

Ji, Yingbiao; Tulin, Alexei V

2016-10-01

Poly(ADP-ribosyl)ation of heterogeneous nuclear ribonucleoproteins (hnRNPs) regulates the posttranscriptional fate of RNA during development. Drosophila hnRNP A1, Hrp38, is required for germ line stem cell maintenance and oocyte localization. The mRNA targets regulated by Hrp38 are mostly unknown. We identified 428 Hrp38-associated gene transcripts in the fly ovary, including mRNA of the translational repressor Nanos. We found that Hrp38 binds to the 3' untranslated region (UTR) of Nanos mRNA, which contains a translation control element. We have demonstrated that translation of the luciferase reporter bearing the Nanos 3' UTR is enhanced by dsRNA-mediated Hrp38 knockdown as well as by mutating potential Hrp38-binding sites. Our data show that poly(ADP-ribosyl)ation inhibits Hrp38 binding to the Nanos 3' UTR, increasing the translation in vivo and in vitro hrp38 and Parg null mutants showed an increased ectopic Nanos translation early in the embryo. We conclude that Hrp38 represses Nanos translation, whereas its poly(ADP-ribosyl)ation relieves the repression effect, allowing restricted Nanos expression in the posterior germ plasm during oogenesis and early embryogenesis. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Lack of commensal flora in H. pylori-infected INS-GAS mice reduces gastritis and delays intraepithelial neoplasia

PubMed Central

Lofgren, Jennifer L.; Whary, Mark T.; Ge, Zhongming; Muthupalani, Sureshkumar; Taylor, Nancy S.; Mobley, Melissa; Potter, Amanda; Varro, Andrea; Eibach, Daniel; Suerbaum, Sebastian; Wang, Timothy C.; Fox, James G.

2010-01-01

Background & Aims Transgenic, insulin–gastrin (INS–GAS) mice have high circulating levels of gastrin. On a FVB/N background, these mice develop spontaneous atrophic gastritis and gastrointestinal intraepithelial neoplasia (GIN) with 80% prevalence 6 months after Helicobacter pylori infection. GIN is associated with gastric atrophy and achlorhydria, predisposing mice to non-helicobacter microbiota overgrowth. We determined if germ-free INS–GAS mice spontaneously develop GIN and if H. pylori accelerates GIN in gnotobiotic INS–GAS mice. Methods We compared gastric lesions and levels of mRNA, serum inflammatory mediators, antibodies, and gastrin among germ-free and H. pylori-monoinfected INS-GAS mice. Microbiota composition of specific pathogen-free (SPF) INS-GAS mice was quantified by pyro-sequencing. Results Germ-free INS-GAS mice had mild hypergastrinemia but did not develop significant gastric lesions until they were 9 months old; they did not develop GIN through 13 months. H. pylori monoassociation caused progressive gastritis, epithelial defects, oxyntic gland atrophy, marked foveolar hyperplasia and dysplasia, and strong serum and tissue proinflammatory immune responses (particularly in male mice) between 5 and 11 months post infection (P<0.05, compared with germ-free controls). Only 2 of 26 female, whereas 8 of 18 male, H. pylori-infected INS-GAS mice developed low- to high-grade GIN by 11 months post infection. Stomachs of H. pylori-infected SPF male mice had significant reductions in Bacteroidetes and significant increases in Firmicutes. Conclusions Gastric lesions take 13 months longer to develop in germ-free INS–GAS mice than male SPF INS-GAS mice. H. pylori-monoassociation accelerated gastritis and GIN but caused less-severe gastric lesions and delayed onset of GIN compared to H. pylori-infected INS-GAS mice with complex gastric microbiota. Changes of gastric microbiota composition might promote GIN in the achlorhydric stomachs of SPF mice. PMID:20950613

Alvocidib and Oxaliplatin With or Without Fluorouracil and Leucovorin Calcium in Treating Patients With Relapsed or Refractory Germ Cell Tumors

ClinicalTrials.gov

2017-01-20

Recurrent Extragonadal Seminoma; Recurrent Malignant Extragonadal Germ Cell Tumor; Recurrent Malignant Extragonadal Non-Seminomatous Germ Cell Tumor; Recurrent Malignant Testicular Germ Cell Tumor; Recurrent Ovarian Germ Cell Tumor; Stage III Testicular Cancer; Stage IV Extragonadal Non-Seminomatous Germ Cell Tumor; Stage IV Extragonadal Seminoma; Stage IV Ovarian Germ Cell Tumor

BMP signaling in the human fetal ovary is developmentally regulated and promotes primordial germ cell apoptosis.

PubMed

Childs, Andrew J; Kinnell, Hazel L; Collins, Craig S; Hogg, Kirsten; Bayne, Rosemary A L; Green, Samira J; McNeilly, Alan S; Anderson, Richard A

2010-08-01

Primordial germ cells (PGCs) are the embryonic precursors of gametes in the adult organism, and their development, differentiation, and survival are regulated by a combination of growth factors collectively known as the germ cell niche. Although many candidate niche components have been identified through studies on mouse PGCs, the growth factor composition of the human PGC niche has not been studied extensively. Here we report a detailed analysis of the expression of components of the bone morphogenetic protein (BMP) signaling apparatus in the human fetal ovary, from postmigratory PGC proliferation to the onset of primordial follicle formation. We find developmentally regulated and reciprocal patterns of expression of BMP2 and BMP4 and identify germ cells to be the exclusive targets of ovarian BMP signaling. By establishing long-term cultures of human fetal ovaries in which PGCs are retained within their physiological niche, we find that BMP4 negatively regulates postmigratory PGC numbers in the human fetal ovary by promoting PGC apoptosis. Finally, we report expression of both muscle segment homeobox (MSX)1 and MSX2 in the human fetal ovary and reveal a selective upregulation of MSX2 expression in human fetal ovary in response to BMP4, suggesting this gene may act as a downstream effector of BMP-induced apoptosis in the ovary, as in other systems. These data reveal for the first time growth factor regulation of human PGC development in a physiologically relevant context and have significant implications for the development of cultures systems for the in vitro maturation of germ cells, and their derivation from pluripotent stem cells.

Sex Reversal in Zebrafish fancl Mutants Is Caused by Tp53-Mediated Germ Cell Apoptosis

PubMed Central

Rodríguez-Marí, Adriana; Cañestro, Cristian; BreMiller, Ruth A.; Nguyen-Johnson, Alexandria; Asakawa, Kazuhide; Kawakami, Koichi; Postlethwait, John H.

2010-01-01

The molecular genetic mechanisms of sex determination are not known for most vertebrates, including zebrafish. We identified a mutation in the zebrafish fancl gene that causes homozygous mutants to develop as fertile males due to female-to-male sex reversal. Fancl is a member of the Fanconi Anemia/BRCA DNA repair pathway. Experiments showed that zebrafish fancl was expressed in developing germ cells in bipotential gonads at the critical time of sexual fate determination. Caspase-3 immunoassays revealed increased germ cell apoptosis in fancl mutants that compromised oocyte survival. In the absence of oocytes surviving through meiosis, somatic cells of mutant gonads did not maintain expression of the ovary gene cyp19a1a and did not down-regulate expression of the early testis gene amh; consequently, gonads masculinized and became testes. Remarkably, results showed that the introduction of a tp53 (p53) mutation into fancl mutants rescued the sex-reversal phenotype by reducing germ cell apoptosis and, thus, allowed fancl mutants to become fertile females. Our results show that Fancl function is not essential for spermatogonia and oogonia to become sperm or mature oocytes, but instead suggest that Fancl function is involved in the survival of developing oocytes through meiosis. This work reveals that Tp53-mediated germ cell apoptosis induces sex reversal after the mutation of a DNA–repair pathway gene by compromising the survival of oocytes and suggests the existence of an oocyte-derived signal that biases gonad fate towards the female developmental pathway and thereby controls zebrafish sex determination. PMID:20661450

CD30 antigen in embryonal carcinoma and embryogenesis and release of the soluble molecule.

PubMed Central

Latza, U.; Foss, H. D.; Dürkop, H.; Eitelbach, F.; Dieckmann, K. P.; Loy, V.; Unger, M.; Pizzolo, G.; Stein, H.

1995-01-01

The expression, serological detection, and possible functional role of the CD30 antigen in Hodgkin's disease and anaplastic large cell lymphoma is well documented. In embryonal carcinoma (EC), the expression of this cytokine receptor has been demonstrated only by immunohistology. Because the CD30 monoclonal antibody Ki-1 was found to cross-react with an unrelated molecule, we examined by in situ hybridization testicular germ cell neoplasms for the presence of CD30-specific transcripts. CD30 mRNA was detectable in the tumor cells of 9 of 9 cases of EC or mixed germ cell tumors with an EC component but in no other nonlymphoid tumors. Thus, the CD30 transcript expression pattern proved to be identical to the immunostaining pattern seen with the CD30-specific monoclonal antibody Ber-H2. By Northern blot analysis, CD30 transcripts could be demonstrated in the EC cell line Tera-2. Employing a highly sensitive second generation sandwich enzyme-linked immunosorbent assay, we could detect the soluble CD30 molecule in 8 of 8 sera from patients with a diagnosis of EC but not in 8 of 10 sera from patients with other testicular germ cell tumors. In fetal tissue, no CD30-expressing germ cells or epithelial cells could be observed. Thus, the cellularly expressed CD30 marker for testicular neoplasms of EC type. Moreover, the serum levels of soluble CD30 antigen seem to be a promising parameter for monitoring patients with EC. Images Figure 1 Figure 2 PMID:7856755

Expression of Apg-1, a member of the Hsp110 family, in the human testis and sperm.

PubMed

Nonoguchi, K; Tokuchi, H; Okuno, H; Watanabe, H; Egawa, H; Saito, K; Ogawa, O; Fujita, J

2001-06-01

Apg-1 encodes a heat shock protein belonging to the Hsp110 family and is inducible by a 32 degrees C to 39 degrees C heat shock in somatic cells. In mouse testicular germ cells Apg-1 mRNA is constitutively expressed depending on the developmental stage. As human Apg-1 has recently been identified, the expression of Apg-1 in the human testis and sperm was investigated. Expression and heat-inducibility of Apg-1 in the human testicular germ cell tumor cell line, NEC8, was analyzed. Using an antimouse Apg-1 antibody, expression of Apg-1 in the human testis and sperm was examined by western blotting after confirmation of the specificity of the antibody. The cells expressing Apg-1 in the testis were further determined by immunohistochemistry. Slight induction of Apg-1 mRNA was detected in NEC8 cells after 32 degrees C to 39 degrees C temperature shift. In the human testis, the antibody specifically recognized Apg-1, which was absent in the testis without germ cells (Sertoli-cell-only syndrome) or arrested at spermatogonia. Spermatocytes and spermatids, but not testicular somatic cells, were positively stained with the anti-Apg-1 antibody. By western blot analysis, Apg-1 was detected in the preparation enriched for sperm from normal volunteers and infertile patients, but not from azoospermia patients. Apg-1 is developmentally expressed in human testicular germ cells and sperm, suggesting its role in spermatogenesis and fertilization. Identification of substrates for Apg-1 chaperone activity will help elucidate its function.

Ethical issues of CRISPR technology and gene editing through the lens of solidarity.

PubMed

Mulvihill, John J; Capps, Benjamin; Joly, Yann; Lysaght, Tamra; Zwart, Hub A E; Chadwick, Ruth

2017-06-01

The avalanche of commentaries on CRISPR-Cas9 technology, a bacterial immune system modified to recognize any short DNA sequence, cut it out, and insert a new one, has rekindled hopes for gene therapy and other applications and raised criticisms of engineering genes in future generations. This discussion draws on articles that emphasize ethics, identified partly through PubMed and Google, 2014-2016. CRISPR-Cas9 has taken the pace and prospects for genetic discovery and applications to a high level, stoking anticipation for somatic gene engineering to help patients. We support a moratorium on germ line manipulation. We place increased emphasis on the principle of solidarity and the public good. The genetic bases of some diseases are not thoroughly addressable with CRISPR-Cas9. We see no new ethical issues, compared with gene therapy and genetic engineering in general, apart from the explosive rate of findings. Other controversies include eugenics, patentability and unrealistic expectations of professionals and the public. Biggest issues are the void of research on human germ cell biology, the appropriate routes for oversight and transparency, and the scientific and ethical areas of reproductive medicine. The principle of genomic solidarity and priority on public good should be a lens for bringing clarity to CRISPR debates. The valid claim of genetic exceptionalism supports restraint on experimentation in human germ cells, given the trans-generational dangers and the knowledge gap in germ cell biology. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Combination Chemotherapy in Treating Young Patients With Recurrent or Resistant Malignant Germ Cell Tumors

ClinicalTrials.gov

2017-11-14

Childhood Extracranial Germ Cell Tumor; Childhood Extragonadal Germ Cell Tumor; Childhood Malignant Ovarian Germ Cell Tumor; Childhood Malignant Testicular Germ Cell Tumor; Ovarian Choriocarcinoma; Ovarian Embryonal Carcinoma; Ovarian Yolk Sac Tumor; Recurrent Childhood Malignant Germ Cell Tumor; Recurrent Malignant Testicular Germ Cell Tumor; Recurrent Ovarian Germ Cell Tumor; Testicular Choriocarcinoma; Testicular Choriocarcinoma and Embryonal Carcinoma; Testicular Choriocarcinoma and Yolk Sac Tumor; Testicular Embryonal Carcinoma; Testicular Embryonal Carcinoma and Yolk Sac Tumor; Testicular Yolk Sac Tumor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu Xiaozhong; Hong, Sung Woo; Moreira, Estefania G.

Gonocytes exist in the neonatal testis and represent a transient population of male germ-line stem cells. It has been shown that stem cell self-renewal and progeny production is probably controlled by the neighboring differentiated cells and extracellular matrix (ECM) in vivo known as niches. Recently, we developed an in vitro three-dimensional (3D) Sertoli cell/gonocyte co-culture (SGC) model with ECM overlay, which creates an in vivo-like niche and supports germ-line stem cell functioning within a 3D environment. In this study, we applied morphological and cytotoxicity evaluations, as well as microarray-based gene expression to examine the effects of different phthalate esters (PE)more » on this model. Known in vivo male developmentally toxic PEs (DTPE) and developmentally non-toxic PEs (DNTPE) were evaluated. We observed that DTPE induced significantly greater dose-dependent morphological changes, a decrease in cell viability and an increase in cytotoxicity compared to those treated with DNTPE. Moreover, the gene expression was more greatly altered by DTPE than by DNTPE and non-supervised cluster analysis allowed the discrimination of DTPE from the DNTPE. Our systems-based GO-Quant analysis showed significant alterations in the gene pathways involved in cell cycle, phosphate transport and apoptosis regulation with DTPE but not with DNTPE treatment. Disruptions of steroidogenesis related-gene expression such as Star, Cyp19a1, Hsd17b8, and Nr4a3 were observed in the DTPE group, but not in the DNTPE group. In summary, our observation on cell viability, cytotoxicity, and microarray-based gene expression analysis induced by PEs demonstrate that our in vitro 3D-SGC system mimicked in vivo responses for PEs and suggests that the 3D-SGC system might be useful in identifying developmental reproductive toxicants.« less

c-kit expression profile and regulatory factors during spermatogonial stem cell differentiation

PubMed Central

2013-01-01

Background It has been proven that c-kit is crucial for proliferation, migration, survival and maturation of spermatogenic cells. A periodic expression of c-kit is observed from primordial germ cells (PGCs) to spermatogenetic stem cells (SSCs), However, the expression profile of c-kit during the entire spermatogenesis process is still unclear. This study aims to reveal and compare c-kit expression profiles in the SSCs before and after the anticipated differentiation, as well as to examine its relationship with retinoic acid (RA) stimulation. Results We have found that there are more than 4 transcripts of c-kit expressed in the cell lines and in the testes. The transcripts can be divided into short and long categories. The long transcripts include the full-length canonical c-kit transcript and the 3′ end short transcript. Short transcripts include the 3.4 kb short transcript and several truncated transcripts (1.9-3.2 kb). In addition, the 3.4 kb transcript (starting from intron 9 and covering exons 10 ~ 21) is discovered to be specifically expressed in the spermatogonia. The extracellular domain of Kit is obtained in the spermatogonia stage, but the intracellular domain (50 kDa) is constantly expressed in both SSCs and spermatogonia. The c-kit expression profiles in the testis and the spermatogonial stem cell lines vary after RA stimulation. The wave-like changes of the quantitative expression pattern of c-kit (increase initially and decrease afterwards) during the induction process are similar to that of the in vivo male germ cell development process. Conclusions There are dynamic transcription and translation changes of c-kit before and after SSCs’ anticipated differentiation and most importantly, RA is a significant upstream regulatory factor for c-kit expression. PMID:24161026

Efficient genome editing of wild strawberry genes, vector development and validation.

PubMed

Zhou, Junhui; Wang, Guoming; Liu, Zhongchi

2018-03-25

The clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 system is an effective genome editing tool for plant and animal genomes. However, there are still few reports on the successful application of CRISPR-Cas9 to horticultural plants, especially with regard to germ-line transmission of targeted mutations. Here, we report high-efficiency genome editing in the wild strawberry Fragaria vesca and its successful application to mutate the auxin biosynthesis gene TAA1 and auxin response factor 8 (ARF8). In our CRISPR system, the Arabidopsis U6 promoter AtU6-26 and the wild strawberry U6 promoter FveU6-2 were each used to drive the expression of sgRNA, and both promoters were shown to lead to high-efficiency genome editing in strawberry. To test germ-line transmission of the edited mutations and new mutations induced in the next generation, the progeny of the primary (T0) transgenic plants carrying the CRISPR construct was analysed. New mutations were detected in the progeny plants at a high efficiency, including large deletions between the two PAM sites. Further, T1 plants harbouring arf8 homozygous knockout mutations grew considerably faster than wild-type plants. The results indicate that our CRISPR vectors can be used to edit the wild strawberry genome at a high efficiency and that both sgRNA design and appropriate U6 promoters contribute to the success of genomic editing. Our results open up exciting opportunities for engineering strawberry and related horticultural crops to improve traits of economic importance. © 2018 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Defects in the synthetic pathway prevent DIF-1 mediated stalk lineage specification cascade in the non-differentiating social amoeba, Acytostelium subglobosum.

PubMed

Mohri, Kurato; Hata, Takashi; Kikuchi, Haruhisa; Oshima, Yoshiteru; Urushihara, Hideko

2014-05-29

Separation of somatic cells from germ-line cells is a crucial event for multicellular organisms, but how this step was achieved during evolution remains elusive. In Dictyostelium discoideum and many other dictyostelid species, solitary amoebae gather and form a multicellular fruiting body in which germ-line spores and somatic stalk cells differentiate, whereas in Acytostelium subglobosum, acellular stalks form and all aggregated amoebae become spores. In this study, because most D. discoideum genes known to be required for stalk cell differentiation have homologs in A. subglobosum, we inferred functional variations in these genes and examined conservation of the stalk cell specification cascade of D. discoideum mediated by the polyketide differentiation-inducing factor-1 (DIF-1) in A. subglobosum. Through heterologous expression of A. subglobosum orthologs of DIF-1 biosynthesis genes in D. discoideum, we confirmed that two of the three genes were functional equivalents, while DIF-methyltransferase (As-dmtA) involved at the final step of DIF-1 synthesis was not. In fact, DIF-1 activity was undetectable in A. subglobosum lysates and amoebae of this species were not responsive to DIF-1, suggesting a lack of DIF-1 production in this species. On the other hand, the molecular function of an A. subglobosum ortholog of DIF-1 responsive transcription factor was equivalent with that of D. discoideum and inhibition of polyketide synthesis caused developmental arrest in A. subglobosum, which could not be rescued by DIF-1 addition. These results suggest that non-DIF-1 polyketide cascades involving downstream transcription factors are required for fruiting body development of A. subglobosum. © 2014. Published by The Company of Biologists Ltd.

Genome engineering via homologous recombination in mouse embryonic stem (ES) cells: an amazingly versatile tool for the study of mammalian biology.

PubMed

Babinet, C; Cohen-Tannoudji, M

2001-09-01

The ability to introduce genetic modifications in the germ line of complex organisms has been a long-standing goal of those who study developmental biology. In this regard, the mouse, a favorite model for the study of the mammals, is unique: indeed not only is it possible since the late seventies, to add genes to the mouse genome like in several other complex organisms but also to perform gene replacement and modification. This has been made possible via two technological breakthroughs: 1) the isolation and culture of embryonic stem cells (ES), which have the unique ability to colonize all the tissues of an host embryo including its germ line; 2) the development of methods allowing homologous recombination between an incoming DNA and its cognate chromosomal sequence (gene "targeting"). As a result, it has become possible to create mice bearing null mutations in any cloned gene (knock-out mice). Such a possibility has revolutionized the genetic approach of almost all aspects of the biology of the mouse. In recent years, the scope of gene targeting has been widened even more, due to the refinement of the knock-out technology: other types of genetic modifications may now be created, including subtle mutations (point mutations, micro deletions or insertions, etc.) and chromosomal rearrangements such as large deletions, duplications and translocations. Finally, methods have been devised which permit the creation of conditional mutations, allowing the study of gene function throughout the life of an animal, when gene inactivation entails embryonic lethality. In this paper, we present an overview of the methods and scenarios used for the programmed modification of mouse genome, and we underline their enormous interest for the study of mammalian biology.

Direct but no transgenerational effects of decitabine and vorinostat on male fertility.

PubMed

Kläver, Ruth; Sánchez, Victoria; Damm, Oliver S; Redmann, Klaus; Lahrmann, Elisabeth; Sandhowe-Klaverkamp, Reinhild; Rohde, Christian; Wistuba, Joachim; Ehmcke, Jens; Schlatt, Stefan; Gromoll, Jörg

2015-01-01

Establishment and maintenance of the correct epigenetic code is essential for a plethora of physiological pathways and disturbed epigenetic patterns can provoke severe consequences, e.g. tumour formation. In recent years, epigenetic drugs altering the epigenome of tumours actively have been developed for anti-cancer therapies. However, such drugs could potentially also affect other physiological pathways and systems in which intact epigenetic patterns are essential. Amongst those, male fertility is one of the most prominent. Consequently, we addressed possible direct effects of two epigenetic drugs, decitabine and vorinostat, on both, the male germ line and fertility. In addition, we checked for putative transgenerational epigenetic effects on the germ line of subsequent generations (F1-F3). Parental adult male C57Bl/6 mice were treated with either decitabine or vorinostat and analysed as well as three subsequent untreated generations derived from these males. Treatment directly affected several reproductive parameters as testis (decitabine & vorinostat) and epididymis weight, size of accessory sex glands (vorinostat), the height of the seminiferous epithelium and sperm concentration and morphology (decitabine). Furthermore, after decitabine administration, DNA methylation of a number of loci was altered in sperm. However, when analysing fertility of treated mice (fertilisation, litter size and sex ratio), no major effect of the selected epigenetic drugs on male fertility was detected. In subsequent generations (F1-F3 generations) only subtle changes on reproductive organs, sperm parameters and DNA methylation but no overall effect on fertility was observed. Consequently, in mice, decitabine and vorinostat neither affected male fertility per se nor caused marked transgenerational effects. We therefore suggest that both drugs do not induce major adverse effects-in terms of male fertility and transgenerational epigenetic inheritance-when used in anti-cancer-therapies.

Sporadic imprinting defects in Prader-Willi syndrome and Angelman syndrome: implications for imprint-switch models, genetic counseling, and prenatal diagnosis.

PubMed Central

Buiting, K; Dittrich, B; Gross, S; Lich, C; Färber, C; Buchholz, T; Smith, E; Reis, A; Bürger, J; Nöthen, M M; Barth-Witte, U; Janssen, B; Abeliovich, D; Lerer, I; van den Ouweland, A M; Halley, D J; Schrander-Stumpel, C; Smeets, H; Meinecke, P; Malcolm, S; Gardner, A; Lalande, M; Nicholls, R D; Friend, K; Schulze, A; Matthijs, G; Kokkonen, H; Hilbert, P; Van Maldergem, L; Glover, G; Carbonell, P; Willems, P; Gillessen-Kaesbach, G; Horsthemke, B

1998-01-01

The Prader-Willi syndrome (PWS) and the Angelman syndrome (AS) are caused by the loss of function of imprinted genes in proximal 15q. In approximately 2%-4% of patients, this loss of function is due to an imprinting defect. In some cases, the imprinting defect is the result of a parental imprint-switch failure caused by a microdeletion of the imprinting center (IC). Here we describe the molecular analysis of 13 PWS patients and 17 AS patients who have an imprinting defect but no IC deletion. Heteroduplex and partial sequence analysis did not reveal any point mutations of the known IC elements, either. Interestingly, all of these patients represent sporadic cases, and some share the paternal (PWS) or the maternal (AS) 15q11-q13 haplotype with an unaffected sib. In each of five PWS patients informative for the grandparental origin of the incorrectly imprinted chromosome region and four cases described elsewhere, the maternally imprinted paternal chromosome region was inherited from the paternal grandmother. This suggests that the grandmaternal imprint was not erased in the father's germ line. In seven informative AS patients reported here and in three previously reported patients, the paternally imprinted maternal chromosome region was inherited from either the maternal grandfather or the maternal grandmother. The latter finding is not compatible with an imprint-switch failure, but it suggests that a paternal imprint developed either in the maternal germ line or postzygotically. We conclude (1) that the incorrect imprint in non-IC-deletion cases is the result of a spontaneous prezygotic or postzygotic error, (2) that these cases have a low recurrence risk, and (3) that the paternal imprint may be the default imprint. PMID:9634532

Two new CHEK2 germ-line variants detected in breast cancer/sarcoma families negative for BRCA1, BRCA2, and TP53 gene mutations.

PubMed

Manoukian, Siranoush; Peissel, Bernard; Frigerio, Simona; Lecis, Daniele; Bartkova, Jirina; Roversi, Gaia; Radice, Paolo; Bartek, Jiri; Delia, Domenico

2011-11-01

CHEK2 gene mutations occur in a subset of patients with familial breast cancer, acting as moderate/low penetrance cancer susceptibility alleles. Although CHEK2 is no longer recognized as a major determinant of the Li-Fraumeni syndrome, a hereditary condition predisposing to cancer at multiple sites, it cannot be ruled out that mutations of this gene play a role in malignancies arising in peculiar multi-cancer families. To assess the contribution of CHEK2 to the breast cancer/sarcoma phenotype, we screened for germ-line sequence variations of the gene among 12 probands from hereditary breast/ovarian cancer families with one case of sarcoma that tested wild-type for mutations in the BRCA1, BRCA2, and TP53 genes. Two cases harbored previously unreported mutations in CHEK2, the c.507delT and c.38A>G, leading to protein truncation (p.Phe169LeufsX2) and amino acid substitution (p.His13Arg), respectively. These mutations were not considered common polymorphic variants, as they were undetected in 230 healthy controls of the same ethnic origin. While the c.38A>G encodes a mutant protein that behaves in biochemical assays as the wild-type form, the c.507delT is a loss-of-function mutation. The identification of two previously unreported CHEK2 variants, including a truncating mutation leading to constitutional haploinsufficiency, in individuals belonging to families selected for breast cancer/sarcoma phenotype, supports the hypothesis that the CHEK2 gene may act as a factor contributing to individual tumor development in peculiar familial backgrounds.

Down-regulation of Wnt10a affects odontogenesis and proliferation in mesenchymal cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Yang, E-mail: Ly10160624@163.com; Han, Dong, E-mail: Donghan@bjmu.edu.cn; Wang, Lei, E-mail: wanglei_dentist@163.com

Highlights: •Down-regulation of Wnt10a in dental mesenchymal cells impairs odontogenesis of reassociated tooth germs. •Dspp is down- and up-regulated after Wnt10a-knockdown and overexpression in dental mesenchymal cells. •Down-regulation of Wnt10a inhibits proliferation of dental mesenchymal cells. -- Abstract: The WNT10a mutation has been found in patients with abnormal odontogenesis. In mice, Wnt10a expression is found in the tooth germ, but its role has not yet been elucidated. We aimed to investigate the role of Wnt10a in odontogenesis. Mesenchymal cells of the first mandibular molar germ at the bell stage were isolated, transfected with Wnt10a SiRNA or plasmid, and reassociated withmore » epithelial part of the molar germ. Scrambled SiRNA or empty vector was used in the control group. The reassociated tooth germs were transplanted into mice subrenal capsules. After gene modification, dental mesenchymal cells cultured in vitro were checked for cell proliferation and the expression of Dspp was examined. All 12 reassociated tooth germs in the control group resumed odontogenesis, while only 5 of 12 in the Wnt10a knockdown group developed into teeth. After Wnt10a knockdown, the mesenchymal cells cultured in vitro presented repressed proliferation. Wnt10a knockdown and overexpression led to both down- and up-regulation of Dspp. We conclude that the down-regulation of Wnt10a impairs odontogensis and cell proliferation, and that Wnt10a regulates Dspp expression in mesenchymal cells. These findings help to elucidate the mechanism of abnormal tooth development in patients with the WNT10A mutation.« less

Lipid phosphate phosphatase activity regulates dispersal and bilateral sorting of embryonic germ cells in Drosophila

PubMed Central

Renault, Andrew D.; Kunwar, Prabhat S.; Lehmann, Ruth

2010-01-01

In Drosophila, germ cell survival and directionality of migration are controlled by two lipid phosphate phosphatases (LPP), wunen (wun) and wunen-2 (wun2). wun wun2 double mutant analysis reveals that the two genes, hereafter collectively called wunens, act redundantly in primordial germ cells. We find that wunens mediate germ cell-germ cell repulsion and that this repulsion is necessary for germ cell dispersal and proper transepithelial migration at the onset of migration and for the equal sorting of the germ cells between the two embryonic gonads during their migration. We propose that this dispersal function optimizes adult fecundity by assuring maximal germ cell occupancy of both gonads. Furthermore, we find that the requirement for wunens in germ cell survival can be eliminated by blocking germ cell migration. We suggest that this essential function of Wunen is needed to maintain cell integrity in actively migrating germ cells. PMID:20431117

Revisiting the human seminiferous epithelium cycle.

PubMed

Nihi, F; Gomes, M L M; Carvalho, F A R; Reis, A B; Martello, R; Melo, R C N; Almeida, F R C L; Chiarini-Garcia, H

2017-06-01

Can all types of testicular germ cells be accurately identified by microscopy techniques and unambiguously distributed in stages of the human seminiferous epithelium cycle (SEC)? By using a high-resolution light microscopy (HRLM) method, which enables an improved visualization of germ cell morphological features, we identified all testicular germ cells in the seminiferous epithelium and precisely grouped them in six well-delimitated SEC stages, thus providing a reliable reference source for staging in man. Morphological characterization of germ cells in human has been done decades ago with the use of conventional histological methods (formaldehyde-based fixative -Zenker-formal- and paraffin embedding). These early studies proposed a classification of the SEC in six stages. However, the use of stages as baseline for morphofunctional evaluations of testicular parenchyma has been difficult because of incomplete morphological identification of germ cells and their random distribution in the human SEC. Testicular tissue from adult and elderly donors with normal spermatogenesis according to Levin's, Johnsen's and Bergmann's scores were used to evaluate germ cell morphology and validate their distribution and frequency in stages throughout human spermatogenesis. Testicular tissue from patients diagnosed with congenital bilateral agenesis of vas deferens (n = 3 adults) or prostate cancer (n = 3 elderly) were fixed in glutaraldehyde and embedded in araldite epoxy resin. Morphological analyses were performed by both light and transmission electron microscopy. HRLM method enabled a reliable morphological identification of all germ cells (spermatogonia, spermatocytes and spermatids) based on high-resolution aspects of euchromatin, heterochromatin and nucleolus. Moreover, acrosomal development of spermatids was clearly revealed. Altogether, our data redefined the limits of each stage leading to a more reliable determination of the SEC in man. Occasionally, germ cells can be absent in some tubular sections. In this situation, it has to be taken into account the germ cell association proposed in the present study to classify the stages. Our findings bring a new focus on the morphology and development of germ cells during the SEC in human. Application of HRLM may be a valuable tool for research studies and clinical andrology helping to understand some testicular diseases and infertility conditions which remain unsolved. Experiments were partially supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Fundação de Amparo à Pesquisa de Minas Gerais (FAPEMIG) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). The authors declare that there are no conflicts of interest. Not applicable. © The Author 2017. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

Normal embryonic and germ cell development in mice lacking alpha 1,3-fucosyltransferase IX (Fut9) which show disappearance of stage-specific embryonic antigen 1.

PubMed

Kudo, Takashi; Kaneko, Mika; Iwasaki, Hiroko; Togayachi, Akira; Nishihara, Shoko; Abe, Kuniya; Narimatsu, Hisashi

2004-05-01

Stage-specific embryonic antigen 1 (SSEA-1), an antigenic epitope defined as a Lewis x carbohydrate structure, is expressed during the 8-cell to blastocyst stages in mouse embryos and in primordial germ cells, undifferentiated embryonic stem cells, and embryonic carcinoma cells. For many years, SSEA-1 has been implicated in the development of mouse embryos as a functional carbohydrate epitope in cell-to-cell interaction during morula compaction. In a previous study, alpha 1,3-fucosyltransferase IX (Fut9) exhibited very strong activity for the synthesis of Lewis x compared to other alpha 1,3-fucosyltransferases in an in vitro substrate specificity assay. Fut4 and Fut9 transcripts were expressed in mouse embryos. The Fut9 transcript was detected in embryonic-day-13.5 gonads containing primordial germ cells, but the Fut4 transcript was not. In order to identify the role of SSEA-1 and determine the key enzyme for SSEA-1 synthesis in vivo, we have generated Fut9-deficient (Fut9(-/-)) mice. Fut9(-/-) mice develop normally, with no gross phenotypic abnormalities, and are fertile. Immunohistochemical analysis revealed an absence of SSEA-1 expression in early embryos and primordial germ cells of Fut9(-/-) mice. Therefore, we conclude that expression of the SSEA-1 epitope in the developing mouse embryo is not essential for embryogenesis in vivo.

Characterization of the Epigenetic Changes During Human Gonadal Primordial Germ Cells Reprogramming.

PubMed

Eguizabal, C; Herrera, L; De Oñate, L; Montserrat, N; Hajkova, P; Izpisua Belmonte, J C

2016-09-01

Epigenetic reprogramming is a central process during mammalian germline development. Genome-wide DNA demethylation in primordial germ cells (PGCs) is a prerequisite for the erasure of epigenetic memory, preventing the transmission of epimutations to the next generation. Apart from DNA demethylation, germline reprogramming has been shown to entail reprogramming of histone marks and chromatin remodelling. Contrary to other animal models, there is limited information about the epigenetic dynamics during early germ cell development in humans. Here, we provide further characterization of the epigenetic configuration of the early human gonadal PGCs. We show that early gonadal human PGCs are DNA hypomethylated and their chromatin is characterized by low H3K9me2 and high H3K27me3 marks. Similarly to previous observations in mice, human gonadal PGCs undergo dynamic chromatin changes concomitant with the erasure of genomic imprints. Interestingly, and contrary to mouse early germ cells, expression of BLIMP1/PRDM1 persists in through all gestational stages in human gonadal PGCs and is associated with nuclear lysine-specific demethylase-1. Our work provides important additional information regarding the chromatin changes associated with human PGCs development between 6 and 13 weeks of gestation in male and female gonads. Stem Cells 2016;34:2418-2428. © 2016 AlphaMed Press.

Differences in Cell Division Rates Drive the Evolution of Terminal Differentiation in Microbes

PubMed Central

Matias Rodrigues, João F.; Rankin, Daniel J.; Rossetti, Valentina; Wagner, Andreas; Bagheri, Homayoun C.

2012-01-01

Multicellular differentiated organisms are composed of cells that begin by developing from a single pluripotent germ cell. In many organisms, a proportion of cells differentiate into specialized somatic cells. Whether these cells lose their pluripotency or are able to reverse their differentiated state has important consequences. Reversibly differentiated cells can potentially regenerate parts of an organism and allow reproduction through fragmentation. In many organisms, however, somatic differentiation is terminal, thereby restricting the developmental paths to reproduction. The reason why terminal differentiation is a common developmental strategy remains unexplored. To understand the conditions that affect the evolution of terminal versus reversible differentiation, we developed a computational model inspired by differentiating cyanobacteria. We simulated the evolution of a population of two cell types –nitrogen fixing or photosynthetic– that exchange resources. The traits that control differentiation rates between cell types are allowed to evolve in the model. Although the topology of cell interactions and differentiation costs play a role in the evolution of terminal and reversible differentiation, the most important factor is the difference in division rates between cell types. Faster dividing cells always evolve to become the germ line. Our results explain why most multicellular differentiated cyanobacteria have terminally differentiated cells, while some have reversibly differentiated cells. We further observed that symbioses involving two cooperating lineages can evolve under conditions where aggregate size, connectivity, and differentiation costs are high. This may explain why plants engage in symbiotic interactions with diazotrophic bacteria. PMID:22511858

Differentiation of presumptive primordial germ cell (pPGC)-like cells in explants into PGCs in experimental tadpoles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ikenishi, K.; Okuda, T.; Nakazato, S.

1984-05-01

A single blastomere containing the ''germ plasm'' of 32-cell stage Xenopus embryos was cultured with (/sup 3/H)thymidine until the control embryos developed to the neurula stage. The explants, showing a spherical mass in which the nuclei of all cells were labeled, were implanted into the prospective place of presumptive primordial germ cells (pPGCs) in the endodermal cell mass of unlabeled host embryos of the neurula stage. Labeled PGCs as well as unlabeled, host PGCs were found in the genital ridges of experimental tadpoles. This indicates that the precursor of germ cells, corresponding to pPGCs in normal embryos of the neurulamore » stage, in the explants migrated to genital ridges just at the right moment to become PGCs, and suggests that the developmental process progressed normally, even in the explants, as far as the differentiation of pPGCs is concerned.« less

Vascular endothelial growth factor and nitric oxide synthase expression in human tooth germ development.

PubMed

Mastrangelo, F; Sberna, M T; Tettamanti, L; Cantatore, G; Tagliabue, A; Gherlone, E

2016-01-01

Vascular Endothelia Growth Factor (VEGF) and Nitric Oxide Synthase (NOS) expression, were evaluated in human tooth germs at two different stages of embryogenesis, to clarify the role of angiogenesis during tooth tissue differentiation and growth. Seventy-two third molar germ specimens were selected during oral surgery. Thirty-six were in the early stage and 36 in the later stage of tooth development. The samples were evaluated with Semi-quantitative Reverse Transcription-Polymerase chain Reaction analyses (RT-PcR), Western blot analysis (WB) and immunohistochemical analysis. Western blot and immunohistochemical analysis showed a VEGF and NOS 1-2-3 positive reaction in all samples analysed. VEGF high positive decrease reaction was observed in stellate reticulum cells, ameloblast and odontoblast clusters in early stage compared to later stage of tooth germ development. Comparable VEGF expression was observed in endothelial cells of early and advanced stage growth. NOS1 and NOS3 expressions showed a high increased value in stellate reticulum cells, and ameloblast and odontoblast clusters in advanced stage compared to early stage of development. The absence or only moderate positive reaction of NOS2 was detected in all the different tissues. Positive NOS2 expression showed in advanced stage of tissue development compared to early stage. The action of VEGF and NOS molecules are important mediators of angiogenesis during dental tissue development. VEGF high positive expression in stellate reticulum cells in the early stage of tooth development compared to the later stage and the other cell types, suggests a critical role of the stellate reticulum during dental embryo-morphogenesis.

Characterization of immortalized dairy goat male germline stem cells (mGSCs).

PubMed

Zhu, Haijing; Ma, Jing; Du, Rui; Zheng, Liming; Wu, Jiang; Song, Wencong; Niu, Zhiwei; He, Xin; Du, Enqi; Zhao, Shanting; Hua, Jinlian

2014-09-01

Male germline stem cells (mGSCs), in charge for the fertility in male testis, are the only kind of adult stem cells that transmit genetic information to next generation, with promising prospects in germplasm resources preservation and optimization, and production of transgenic animals. Mouse male germline stem cell lines have been established and are valuable for studying the mechanisms of spermatogenesis. However, there is a lack of stable mGSC cell lines in livestock, which restricts the progress of transgenic research and related biotechnology. Here, we firstly established an immortalized dairy goat mGSC cell line to study the biological properties and the signaling pathways associated with mGSCs self-renewal and differentiation. The ectopic factors SV40 large T antigen and Bmi1 genes were transduced into dairy goat mGSCs, and the results showed that the proliferation of these cells that were named mGSCs-I-SB was improved significantly. They maintained the typical characteristics including the expression of mGSC markers, and the potential to differentiate into all three germ layers, sperm-like cells in vitro. Additionally, mGSCs-I-SB survived and differentiated into three germ layer cell types when they were transplanted into chicken embryos. Importantly, the cells also survived in mouse spermatogenesis deficiency model testis which seemed to be the golden standard to examine mGSCs. Conclusively, our results demonstrate that mGSCs-I-SB present the characteristics of mGSCs and may promote the future study on goat mGSCs. © 2014 Wiley Periodicals, Inc.

Masking of central diabetes insipidus and hypogonadotrophic hypogonadism by germ cell tumour in suprasellar--pineal region.

PubMed

Isa, S H Md; Wong, M; Khalid, B A K

2006-12-01

A patient with beta hCG-secreting germ cell carcinoma of the pineal and suprasellar regions presented with hydrocephalus, Parinaud's syndrome, hypopituitarism and polyuria. Central diabetes insipidus was strongly suspected although the water deprivation test was not diagnostic. The polyuria however, responded to ADH analogue when the hypothyroidism and hypocortisolism were treated. Pubertal development was evident and serum testosterone was normal despite the low FSH/LH, suggesting hCG stimulation of Leydig cells. This case illustrates that a beta hCG-germ cell tumour of the suprasellar region causing hypopituitarism can mask the presence of central diabetes insipidus and hypogonadotrophic hypogonadism.

Children’s Oncology Group’s 2013 Blueprint for Research: Rare Tumors

PubMed Central

Rodriguez-Galindo, Carlos; Krailo, Mark; Frazier, Lindsay; Chintagumpala, Murali; Amatruda, James; Katzenstein, Howard; Malogolowkin, Marcio; Spector, Logan; Pashankar, Farzana; Meyers, Rebecka; Tomlinson, Gail

2015-01-01

In the US, approximately 2,000 children are diagnosed with rare cancers each year, with 5-year survival ranging from <20% for children with advanced carcinomas to >95% for children with intraocular retinoblastoma or localized germ cell tumors. During the last years, 12 clinical studies have been successfully completed in children with retinoblastoma, liver tumors, germ cell tumors, and infrequent malignancies, including therapeutic, epidemiologic, and biologic studies. Current efforts are centered in the development of large international collaborations to consolidate evidence-based definitions and risk stratifications that will support international Phase 3 clinical trials in germ cell tumors, hepatoblastoma, and other rare cancers. PMID:23255219

Genetic changes associated with testicular cancer susceptibility.

PubMed

Pyle, Louise C; Nathanson, Katherine L

2016-10-01

Testicular germ cell tumor (TGCT) is a highly heritable cancer primarily affecting young white men. Genome-wide association studies (GWAS) have been particularly effective in identifying multiple common variants with strong contribution to TGCT risk. These loci identified through association studies have implicated multiple genes as associated with TGCT predisposition, many of which are unique among cancer types, and regulate processes such as pluripotency, sex specification, and microtubule assembly. Together these biologically plausible genes converge on pathways involved in male germ cell development and maturation, and suggest that perturbation of them confers susceptibility to TGCT, as a developmental defect of germ cell differentiation. Copyright © 2016 Elsevier Inc. All rights reserved.

Imatinib Mesylate in Treating Patients With Progressive, Refractory, or Recurrent Stage II or Stage III Testicular or Ovarian Cancer

ClinicalTrials.gov

2013-01-15

Ovarian Dysgerminoma; Recurrent Malignant Testicular Germ Cell Tumor; Recurrent Ovarian Germ Cell Tumor; Stage II Malignant Testicular Germ Cell Tumor; Stage II Ovarian Germ Cell Tumor; Stage III Malignant Testicular Germ Cell Tumor; Stage III Ovarian Germ Cell Tumor; Testicular Seminoma