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Sample records for homeotic gene sex

  1. Setting limits on homeotic gene function: restraint of Sex combs reduced activity by teashirt and other homeotic genes.

    PubMed Central

    Andrew, D J; Horner, M A; Petitt, M G; Smolik, S M; Scott, M P

    1994-01-01

    Each of the homeotic genes of the HOM or HOX complexes is expressed in a limited domain along the anterior-posterior axis. Each homeotic protein directs the formation of characteristic structures, such as wings or ribs. In flies, when a heat shock-inducible homeotic gene is used to produce a homeotic protein in all cells of the embryo, only some cells respond by altering their fates. We have identified genes that limit where the homeotic gene Sex combs reduced (Scr) can affect cell fates in the Drosophila embryo. In the abdominal cuticle Scr is prevented from inducing prothoracic structures by the three bithorax complex (BX-C) homeotic genes. However, two of the BX-C homeotic genes, Ultrabithorax (Ubx) and abdominal-A (abd-A), have no effect on the ability of Scr to direct the formation of salivary glands. Instead, salivary gland induction by Scr is limited in the trunk by the homeotic gene teashirt (tsh) and in the last abdominal segment by the third BX-C gene, Abdominal-B (AbdB). Therefore, spatial restrictions on homeotic gene activity differ between tissues and result both from the regulation of homeotic gene transcription and from restraints on where homeotic proteins can function. Images PMID:7907545

  2. Characterization of the cis-regulatory region of the Drosophila homeotic gene Sex combs reduced

    SciTech Connect

    Gindhart, J.G. Jr.; King, N.A.; Kaufman, T.C.

    1995-02-01

    The Drosophilia homeotic gene Sex combs reduced (Scr) controls the segmental identity of the labial and prothoracic segments in the embryo and adult. It encodes a sequence-specific transcription factor that controls, in concert with other gene products, differentiative pathways of tissues in which Scr is expressed. During embryogenesis, Scr accumulation is observed in a discrete spatiotemporal pattern that includes the labial and prothoracic ectoderm, the subesophageal ganglion of the ventral nerve cord and the visceral mesoderm of the anterior and posterior midgut. Previous analyses have demonstrated that breakpoint mutations located in a 75-kb interval, including the Scr transcription unit and 50 kb of upstream DNA, cause Scr misexpression during development, presumably because these mutations remove Scr cis-regulatory sequences from the proximity of the Scr promoter. To gain a better understanding of the regulatory interactions necessary for the control of Scr transcription during embryogenesis, we have begun a molecular analysis of the Scr regulatory interval. DNA fragments from this 75-kb region were subcloned into P-element vectors containing either an Scr-lacZ or hsp70-lacZ fusion gene, and patterns of reporter gene expression were assayed in transgenic embryos. Several fragments appear to contain Scr regulatory sequences, as they direct reporter gene expression in patterns similar to those normally observed for Scr, whereas other DNA fragments direct Scr reporter gene expression in developmentally interesting but non-Scr-like patterns during embryogenesis. Scr expression in some tissues appears to be controlled by multiple regulatory elements that are separated, in some cases, by more than 20 kb of intervening DNA. This analysis provides an entry point for the study of how Scr transcription is regulated at the molecular level. 60 refs., 7 figs., 1 tab.

  3. Characterization of the Cis-Regulatory Region of the Drosophila Homeotic Gene Sex Combs Reduced

    PubMed Central

    Gindhart-Jr., J. G.; King, A. N.; Kaufman, T. C.

    1995-01-01

    The Drosophila homeotic gene Sex combs reduced (Scr) controls the segmental identity of the labial and prothoracic segments in the embryo and adult. It encodes a sequence-specific transcription factor that controls, in concert with other gene products, differentiative pathways of tissues in which Scr is expressed. During embryogenesis, Scr accumulation is observed in a discrete spatiotemporal pattern that includes the labial and prothoracic ectoderm, the subesophageal ganglion of the ventral nerve cord and the visceral mesoderm of the anterior and posterior midgut. Previous analyses have demonstrated that breakpoint mutations located in a 75-kb interval, including the Scr transcription unit and 50 kb of upstream DNA, cause Scr misexpression during development, presumably because these mutations remove Scr cis-regulatory sequences from the proximity of the Scr promoter. To gain a better understanding of the regulatory interactions necessary for the control of Scr transcription during embryogenesis, we have begun a molecular analysis of the Scr regulatory interval. DNA fragments from this 75-kb region were subcloned into P-element vectors containing either an Scr-lacZ or hsp70-lacZ fusion gene, and patterns of reporter gene expression were assayed in transgenic embryos. Several fragments appear to contain Scr regulatory sequences, as they direct reporter gene expression in patterns similar to those normally observed for Scr, whereas other DNA fragments direct Scr reporter gene expression in developmentally interesting but non-Scr-like patterns during embryogenesis. Scr expression in some tissues appears to be controlled by multiple regulatory elements that are separated, in some cases, by more than 20 kb of intervening DNA. Interestingly, regulatory sequences that direct reporter gene expression in an Scr-like pattern in the anterior and posterior midgut are imbedded in the regulatory region of the segmentation gene fushi tarazu (ftz), which is normally located

  4. Identification of polycomb and trithorax group responsive elements in the regulatory region of the Drosophila homeotic gene Sex combs reduced

    SciTech Connect

    Gindhart, J.G. Jr.; Kaufman, T.C.

    1995-02-01

    The Drosophilia homeotic gene Sex combs reduced (Scr) is necessary for the establishment and maintenance of the morphological identity of the labial and prothoracic segments. In the early embryo, its expression pattern is established through the activity of several gap and segmentation gene products, as well as other transcription factors. Once established, the Polycomb group (Pc-G) and trithorax group (trx-G) gene products maintain the spatial pattern of Scr expression for the remainder of development. We report the identification of DNA fragments in the Scr regulatory region that may be important for its regulation by Polycomb and trithorax group gene products. When DNA fragments containing these regulatory sequences are subcloned into P-element vectors containing a white minigene, transformants containing these constructs exhibit mosaic patterns of pigmentation in the adult eye, indicating that white minigene expression is repressed in a clonally heritable manner. The size of pigmented and nonpigmented clones in the adult eye suggests that the event determining whether a cell in the eye anlagen will express white occurs at least as early as the first larval instar. The amount of white minigene repression is reduced in some Polycomb group mutants, whereas repression is enhanced in flies mutant for a subset of trithorax group loci. The repressor activity of one fragment, normally located in Scr Intron 2, is increased when it is able to homologously pair, a property consistent with genetic data suggesting that Scr exhibits transvection. Another Scr regulatory fragment, normally located 40 kb upstream of the Scr promoter, silences ectopic expression of an Scr-lacZ fusion gene in the embryo and does so in a Polycomb-dependent manner. We propose that the regulatory sequences located within these DNA fragments may normally mediate the regulation of Scr by proteins encoded by members of Polycomb and trithorax group loci. 98 refs., 6 figs., 4 tabs.

  5. Regulatory mechanisms for floral homeotic gene expression.

    PubMed

    Liu, Zhongchi; Mara, Chloe

    2010-02-01

    Proper regulation of floral homeotic gene (or ABCE gene) expression ensures the development of floral organs in the correct number, type, and precise spatial arrangement. This review summarizes recent advances on the regulation of floral homeotic genes, highlighting the variety and the complexity of the regulatory mechanisms involved. As flower development is one of the most well characterized developmental processes in higher plants, it facilitates the discovery of novel regulatory mechanisms. To date, mechanisms for the regulation of floral homeotic genes range from transcription to post-transcription, from activators to repressors, and from microRNA- to ubiquitin-mediated post-transcriptional regulation. Region-specific activation of floral homeotic genes is dependent on the integration of a flower-specific activity provided by LEAFY (LFY) and a region- and stage-specific activating function provided by one of the LFY cofactors. Two types of regulatory loops, the feed-forward and the feedback loop, provide properly timed gene activation and subsequent maintenance and refinement in proper spatial and temporal domains of ABCE genes. Two different microRNA/target modules may have been independently recruited in different plant species to regulate C gene expression. Additionally, competition among different MADS box proteins for common interacting partners may represent a mechanism in whorl boundary demarcation. Future work using systems approaches and the development of non-model plants will provide integrated views on floral homeotic gene regulation and insights into the evolution of morphological diversity in flowering plants. Copyright 2009 Elsevier Ltd. All rights reserved.

  6. The gap gene Krüppel of Rhodnius prolixus is required for segmentation and for repression of the homeotic gene sex comb-reduced.

    PubMed

    Lavore, Andrés; Esponda-Behrens, Natalia; Pagola, Lucía; Rivera-Pomar, Rolando

    2014-03-01

    The establishment of the anterior-posterior segmentation in insects requires the concerted action of a hierarchical gene network. Here, we study the orthologue of Krüppel gap gene in the hemipteran Rhodnius prolixus (Rp-Kr). We characterized its structure, expression pattern and function. The genomic sequence upstream of the Rp-Kr transcriptional unit shows a putative regulatory region conserved in the orthologue genes from Drosophila melanogaster and Tribolium castaneum. Rp-Kr expression is zygotic and it is expressed in the anterior half of the embryo (the posterior half of the egg) during the blastoderm stage and germ band formation; later, during germ band extension, it is expressed in a central domain, from T2 to A3. The Rp-Kr loss of function phenotypes shows disrupted thoracic and abdominal segmentation. Embryos with weak segmentation phenotypes show homeotic transformations, in which an ectopic tibial comb, typical of T1 leg, appears in T2, which correlates with the ectopic expression of Rp-sex-comb reduced in this leg. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. An essential role of even-skipped for homeotic gene expression in the Drosophila visceral mesoderm.

    PubMed Central

    Tremml, G; Bienz, M

    1989-01-01

    We have analysed homeotic gene expression in the embryonic visceral mesoderm of segmentation mutants by antibody staining against Ultrabithorax, Antennapedia and Sex combs reduced protein. We found that even-skipped (eve) function is crucially required for homeotic gene expression, whereas most other segmentation mutations have only minor effects on position and/or width of the homeotic expression domains in this germ layer. Analysis of pair-rule double mutants indicates that complete loss of homeotic gene activity in the visceral mesoderm, as observed in amorphic eve mutants, correlates with loss of engrailed (en) expression in the epidermis and loss of segmentation. We suggest that the establishment of parasegment borders, a consequence of eve expression and witnessed by subsequent en expression, is a necessary precondition for homeotic gene expression in the visceral mesoderm. Images PMID:2573527

  8. Chromatin remodeling protein INO80 has a role in regulation of homeotic gene expression in Drosophila.

    PubMed

    Bhatia, Shipra; Pawar, Hema; Dasari, Vasanthi; Mishra, Rakesh K; Chandrashekaran, Shanti; Brahmachari, Vani

    2010-06-01

    The homologues of yeast INO80 are identified across phyla from Caenorhabditis elegans to human. In Drosophila it has been shown that dINO80 forms a complex with Pleiohomeotic but does not interact with Hox PRE (polycomb responsive element). As some proteins of the INO80 complex are implicated in homeotic gene regulation, we examined if dINO80 is involved in regulation of homeotic genes. We find that dINO80 null mutants generated by imprecise excision of P-element are late embryonic lethals and show homeotic transformation. We detect misexpression of homeotic genes like Sex-comb reduced, Antennapedia, Ultrabithorax and Abdominal-B in dIno80 mutant embryos by immunostaining which is further substantiated by quantitative PCR. Polycomb phenotype in dIno80-Pc is enhanced in double mutants. Concurrently, the localization of dINO80 to sequences upstream of misexpressed genes in vivo shows that dINO80 is involved in homeotic gene regulation and probably through its interactions with PcG-trxG complexes.

  9. Cloning of the homeotic Sex combs reduced gene in Drosophila and in situ localization of its transcripts.

    PubMed

    Kuroiwa, A; Kloter, U; Baumgartner, P; Gehring, W J

    1985-12-30

    We have extended our ;chromosomal walk' in the Antennapedia-complex (ANT-C) by isolating overlapping DNA sequences spanning the chromosomal segment between Antennapedia (Antp) and Deformed (Dfd). The transcription units, homeoboxes and M-repeats were mapped within this region. Four transcription units Antp, fushi tarazu (ftz), Sex combs reduced (Scr) and Dfd contain both a homeobox and an M repeat, whereas at least two additional transcription units, x and z, were found to lack these elements. The Scr locus was identified by deletion mapping. It consists of at least two exonic regions separated by a large intron. The homeobox is located in the 3' exon and is 82% homologous to the one in Antp. Scr encodes a major 3.9-kb RNA. A corresponding cDNA clone was used as a probe for in situ hybridization to sections of various embryonic stages. At gastrula stages Scr transcripts accumulate in the posterior head and the anterior thoracic region of the germ band. At later stages a strong accumulation of transcripts is observed in the suboesophageal and the prothoracic ganglion of the ventral nervous system.

  10. [Homeotic genes and their role in development of wheat's morphological traits].

    PubMed

    Prokopyk, D O; Ternovs'ka, T K

    2011-01-01

    The information concerning major families of plant homeotic genes, ways of their expression regulation and role in plant morphogenesis is outlined. Role of known homeotic genes in wheat development and growth habit establishment is presented. A supposed role of homeotic genes in major morphologic traits formation is discussed.

  11. An autoregulatory enhancer element of the Drosophila homeotic gene Deformed.

    PubMed

    Bergson, C; McGinnis, W

    1990-12-01

    The stable determination of different anterior-posterior regions of the Drosophila embryo is controlled by the persistent expression of homeotic selector genes. One mechanism that has been proposed to explain the persistent expression of the homeotic gene Deformed is an autoactivation circuit that would be used once Deformed expression had been established by earlier acting patterning genes. Here we show that a large cis-regulatory element mapping approximately 5 kb upstream of the Deformed transcription start has the properties predicted for a Deformed autoregulatory enhancer. This element provides late, spatially localized expression in the epidermal cells of the maxillary and mandibular segments which is wholly dependent upon endogenous Deformed function. In addition, the autoregulatory enhancer can be activated ectopically in embryos and in imaginal disc cells by ectopic expression of Deformed protein. Deletion analysis of the autoregulatory element indicates that it contains compartment specific sub-elements similar to those of other homeotic loci.

  12. Evolution in action: following function in duplicated floral homeotic genes.

    PubMed

    Causier, Barry; Castillo, Rosa; Zhou, Junli; Ingram, Richard; Xue, Yongbiao; Schwarz-Sommer, Zsuzsanna; Davies, Brendan

    2005-08-23

    Gene duplication plays a fundamental role in evolution by providing the genetic material from which novel functions can arise. Newly duplicated genes can be maintained by subfunctionalization (the duplicated genes perform different aspects of the original gene's function) and/or neofunctionalization (one of the genes acquires a novel function). PLENA in Antirrhinum and AGAMOUS in Arabidopsis are the canonical C-function genes that are essential for the specification of reproductive organs. These functionally equivalent genes encode closely related homeotic MADS-box transcription factors. Using genome synteny, we confirm phylogenetic analyses showing that PLENA and AGAMOUS are nonorthologous genes derived from a duplication in a common ancestor. Their respective orthologs, SHATTERPROOF in Arabidopsis and FARINELLI in Antirrhinum, have undergone independent subfunctionalization via changes in regulation and protein function. Surprisingly, the functional divergence between PLENA and FARINELLI, is morphologically manifest in both transgenic Antirrhinum and Arabidopsis. This provides a clear illustration of a random evolutionary trajectory for gene functions after a duplication event. Different members of a duplicated gene pair have retained the primary homeotic functions in different lineages, illustrating the role of chance in evolution. The differential ability of the Antirrhinum genes to promote male or female development provides a striking example of subfunctionalization at the protein level.

  13. Drosophila fushi tarazu. a gene on the border of homeotic function.

    PubMed

    Löhr, U; Yussa, M; Pick, L

    2001-09-18

    Hox genes specify cell fate and regional identity during animal development. These genes are present in evolutionarily conserved clusters thought to have arisen by gene duplication and divergence. Most members of the Drosophila Hox complex (HOM-C) have homeotic functions. However, a small number of HOM-C genes, such as the segmentation gene fushi tarazu (ftz), have nonhomeotic functions. If these genes arose from a homeotic ancestor, their functional properties must have changed significantly during the evolution of modern Drosophila. Here, we have asked how Drosophila ftz evolved from an ancestral homeotic gene to obtain a novel function in segmentation. We expressed Ftz proteins at various developmental stages to assess their potential to regulate segmentation and to generate homeotic transformations. Drosophila Ftz protein has lost the inherent ability to mediate homeosis and functions exclusively in segmentation pathways. In contrast, Ftz from the primitive insect Tribolium (Tc-Ftz) has retained homeotic potential, generating homeotic transformations in larvae and adults and retaining the ability to repress homothorax, a hallmark of homeotic genes. Similarly, Schistocerca Ftz (Sg-Ftz) caused homeotic transformations of antenna toward leg. Primitive Ftz orthologs have moderate segmentation potential, reflected by weak interactions with the segmentation-specific cofactor Ftz-F1. Thus, Ftz orthologs represent evolutionary intermediates that have weak segmentation potential but retain the ability to act as homeotic genes. ftz evolved from an ancestral homeotic gene as a result of changes in both regulation of expression and specific alterations in the protein-coding region. Studies of ftz orthologs from primitive insects have provided a "snap-shot" view of the progressive evolution of a Hox protein as it took on segmentation function and lost homeotic potential. We propose that the specialization of Drosophila Ftz for segmentation resulted from loss and gain of

  14. Conservation of floral homeotic gene function between Arabidopsis and antirrhinum.

    PubMed Central

    Irish, V F; Yamamoto, Y T

    1995-01-01

    Several homeotic genes controlling floral development have been isolated in both Antirrhinum and Arabidopsis. Based on the similarities in sequence and in the phenotypes elicited by mutations in some of these genes, it has been proposed that the regulatory hierarchy controlling floral development is comparable in these two species. We have performed a direct experimental test of this hypothesis by introducing a chimeric Antirrhinum Deficiens (DefA)/Arabidopsis APETALA3 (AP3) gene, under the control of the Arabidopsis AP3 promoter, into Arabidopsis. We demonstrated that this transgene is sufficient to partially complement severe mutations at the AP3 locus. In combination with a weak ap3 mutation, this transgene is capable of completely rescuing the mutant phenotype to a fully functional wild-type flower. These observations indicate that despite differences in DNA sequence and expression, DefA coding sequences can compensate for the loss of AP3 gene function. We discuss the implications of these results for the evolution of homeotic gene function in flowering plants. PMID:7580255

  15. Spatial regulation of the Antennapedia and Ultrabithorax homeotic genes during Drosophila early development.

    PubMed Central

    Irish, V F; Martinez-Arias, A; Akam, M

    1989-01-01

    Both maternally supplied products and zygotically acting segmentation genes are required to establish the segment pattern of the Drosophila embryo. These genes are thought to act in part by regulating the expression of the homeotic genes. Products of the maternal and zygotic gap genes are present in the egg prior to blastoderm formation, when the homeotic genes are initially expressed within precisely bounded domains. In order to assess the first regulatory interactions between some of these gap gene products and the homeotic genes, we have examined the spatial distribution of transcripts arising from the homeotic Antp and Ubx genes during early embryogenesis in various mutant backgrounds. Here we show that mutations in both maternally and zygotically acting gap genes differentially affect the initial spatial domains of transcripts arising from each of these homeotic gene promoters. Later in embryogenesis, the patterns of homeotic gene expression change in both the wild-type and mutant cases, suggesting that other regulatory activities come into play. We propose a model in which the initial activation of each homeotic gene promoter depends on a unique combination of gap and pair-rule gene activities. Images PMID:2569971

  16. SUPERMAN, a regulator of floral homeotic genes in Arabidopsis.

    PubMed

    Bowman, J L; Sakai, H; Jack, T; Weigel, D; Mayer, U; Meyerowitz, E M

    1992-03-01

    We describe a locus, SUPERMAN, mutations in which result in extra stamens developing at the expense of the central carpels in the Arabidopsis thaliana flower. The development of superman flowers, from initial primordium to mature flower, is described by scanning electron microscopy. The development of doubly and triply mutant strains, constructed with superman alleles and previously identified homeotic mutations that cause alterations in floral organ identity, is also described. Essentially additive phenotypes are observed in superman agamous and superman apetala2 double mutants. The epistatic relationships observed between either apetala3 or pistillata and superman alleles suggest that the SUPERMAN gene product could be a regulator of these floral homeotic genes. To test this, the expression patterns of AGAMOUS and APETALA3 were examined in superman flowers. In wild-type flowers, APETALA3 expression is restricted to the second and third whorls where it is required for the specification of petals and stamens. In contrast, in superman flowers, APETALA3 expression expands to include most of the cells that would normally constitute the fourth whorl. This ectopic APETALA3 expression is proposed to be one of the causes of the development of the extra stamens in superman flowers. The spatial pattern of AGAMOUS expression remains unaltered in superman flowers as compared to wild-type flowers. Taken together these data indicate that one of the functions of the wild-type SUPERMAN gene product is to negatively regulate APETALA3 in the fourth whorl of the flower. In addition, superman mutants exhibit a loss of determinacy of the floral meristem, an effect that appears to be mediated by the APETALA3 and PISTILLATA gene products.

  17. Deciphering the combinatorial architecture of a Drosophila homeotic gene enhancer.

    PubMed

    Drewell, Robert A; Nevarez, Michael J; Kurata, Jessica S; Winkler, Lauren N; Li, Lily; Dresch, Jacqueline M

    2014-02-01

    In Drosophila, the 330 kb bithorax complex regulates cellular differentiation along the anterior–posterior axis during development in the thorax and abdomen and is comprised of three homeotic genes: Ultrabithorax, abdominal-A, and Abdominal-B. The expression of each of these genes is in turn controlled through interactions between transcription factors and a number of cis-regulatory modules in the neighboring intergenic regions. In this study, we examine how the sequence architecture of transcription factor binding sites mediates the functional activity of one of these cis-regulatory modules. Using computational, mathematical modeling and experimental molecular genetic approaches we investigate the IAB7b enhancer, which regulates Abdominal-B expression specifically in the presumptive seventh and ninth abdominal segments of the early embryo. A cross-species comparison of the IAB7b enhancer reveals an evolutionarily conserved signature motif containing two FUSHI-TARAZU activator transcription factor binding sites. We find that the transcriptional repressors KNIRPS, KRUPPEL and GIANT are able to restrict reporter gene expression to the posterior abdominal segments, using different molecular mechanisms including short-range repression and competitive binding. Additionally, we show the functional importance of the spacing between the two FUSHI-TARAZU binding sites and discuss the potential importance of cooperativity for transcriptional activation. Our results demonstrate that the transcriptional output of the IAB7b cis-regulatory module relies on a complex set of combinatorial inputs mediated by specific transcription factor binding and that the sequence architecture at this enhancer is critical to maintain robust regulatory function.

  18. Deciphering the combinatorial architecture of a Drosophila homeotic gene enhancer

    PubMed Central

    Drewell, Robert A.; Nevarez, Michael J.; Kurata, Jessica S.; Winkler, Lauren N.; Li, Lily; Dresch, Jacqueline M.

    2013-01-01

    Summary In Drosophila, the 330 kb bithorax complex regulates cellular differentiation along the anterio-posterior axis during development in the thorax and abdomen and is comprised of three homeotic genes: Ultrabithorax, abdominal-A, and Abdominal-B. The expression of each of these genes is in turn controlled through interactions between transcription factors and a number of cis-regulatory modules in the neighboring intergenic regions. In this study, we examine how the sequence architecture of transcription factor binding sites mediates the functional activity of one of these cis-regulatory modules. Using computational, mathematical modeling and experimental molecular genetic approaches we investigate the IAB7b enhancer, which regulates Abdominal-B expression specifically in the presumptive seventh and ninth abdominal segments of the early embryo. A cross-species comparison of the IAB7b enhancer reveals an evolutionarily conserved signature motif containing two FUSHI-TARAZU activator transcription factor binding sites. We find that the transcriptional repressors KNIRPS, KRUPPEL and GIANT are able to restrict reporter gene expression to the posterior abdominal segments, using different molecular mechanisms including short-range repression and competitive binding. Additionally, we show the functional importance of the spacing between the two FUSHI-TARAZU binding sites and discuss the potential importance of cooperativity for transcriptional activation. Our results demonstrate that the transcriptional output of the IAB7b cis-regulatory module relies on a complex set of combinatorial inputs mediated by specific transcription factor binding and that the sequence architecture at this enhancer is critical to maintain robust regulatory function. PMID:24514265

  19. The Tribolium homeotic gene Abdominal is homologous to abdominal-A of the Drosophila bithorax complex

    NASA Technical Reports Server (NTRS)

    Stuart, J. J.; Brown, S. J.; Beeman, R. W.; Denell, R. E.; Spooner, B. S. (Principal Investigator)

    1993-01-01

    The Abdominal gene is a member of the single homeotic complex of the beetle, Tribolium castaneum. An integrated developmental genetic and molecular analysis shows that Abdominal is homologous to the abdominal-A gene of the bithorax complex of Drosophila. abdominal-A mutant embryos display strong homeotic transformations of the anterior abdomen (parasegments 7-9) to PS6, whereas developmental commitments in the posterior abdomen depend primarily on Abdominal-B. In beetle embryos lacking Abdominal function, parasegments throughout the abdomen are transformed to PS6. This observation demonstrates the general functional significance of parasegmental expression among insects and shows that the control of determinative decisions in the posterior abdomen by homeotic selector genes has undergone considerable evolutionary modification.

  20. Differential DNA sequence recognition is a determinant of specificity in homeotic gene action.

    PubMed Central

    Ekker, S C; von Kessler, D P; Beachy, P A

    1992-01-01

    The homeotic genes of Drosophila encode transcriptional regulatory proteins that specify distinct segment identities. Previous studies have implicated the homeodomain as a major determinant of biological specificity within these proteins, but have not established the physical basis of this specificity. We show here that the homeodomains encoded by the Ultrabithorax and Deformed homeotic genes bind optimally to distinct DNA sequences and have mapped the determinants responsible for differential recognition. We further show that relative transactivation by these two proteins in a simple in vivo system can differ by nearly two orders of magnitude. Such differences in DNA sequence recognition and target activation provide a biochemical basis for at least part of the biological specificity of homeotic gene action. Images PMID:1356765

  1. The Tribolium homeotic gene Abdominal is homologous to abdominal-A of the Drosophila bithorax complex

    NASA Technical Reports Server (NTRS)

    Stuart, J. J.; Brown, S. J.; Beeman, R. W.; Denell, R. E.; Spooner, B. S. (Principal Investigator)

    1993-01-01

    The Abdominal gene is a member of the single homeotic complex of the beetle, Tribolium castaneum. An integrated developmental genetic and molecular analysis shows that Abdominal is homologous to the abdominal-A gene of the bithorax complex of Drosophila. abdominal-A mutant embryos display strong homeotic transformations of the anterior abdomen (parasegments 7-9) to PS6, whereas developmental commitments in the posterior abdomen depend primarily on Abdominal-B. In beetle embryos lacking Abdominal function, parasegments throughout the abdomen are transformed to PS6. This observation demonstrates the general functional significance of parasegmental expression among insects and shows that the control of determinative decisions in the posterior abdomen by homeotic selector genes has undergone considerable evolutionary modification.

  2. Regulation of APETALA3 floral homeotic gene expression by meristem identity genes.

    PubMed

    Lamb, Rebecca S; Hill, Theresa A; Tan, Queenie K-G; Irish, Vivian F

    2002-05-01

    The Arabidopsis APETALA3 (AP3) floral homeotic gene is required for specifying petal and stamen identities, and is expressed in a spatially limited domain of cells in the floral meristem that will give rise to these organs. Here we show that the floral meristem identity genes LEAFY (LFY) and APETALA1 (AP1) are required for the activation of AP3. The LFY transcription factor binds to a sequence, with dyad symmetry, that lies within a region of the AP3 promoter required for early expression of AP3. Mutation of this region abolishes LFY binding in vitro and in yeast one hybrid assays, but has no obvious effect on AP3 expression in planta. Experiments using a steroid-inducible form of LFY show that, in contrast to its direct transcriptional activation of other floral homeotic genes, LFY acts in both a direct and an indirect manner to regulate AP3 expression. This LFY-induced expression of AP3 depends in part on the function of the APETALA1 (AP1) floral homeotic gene, since mutations in AP1 reduce LFY-dependent induction of AP3 expression. LFY therefore appears to act through several pathways, one of which is dependent on AP1 activity, to regulate AP3 expression.

  3. ATX-1, an Arabidopsis homolog of trithorax, activates flower homeotic genes.

    PubMed

    Alvarez-Venegas, Raul; Pien, Stephane; Sadder, Monther; Witmer, Xiaohong; Grossniklaus, Ueli; Avramova, Zoya

    2003-04-15

    The genes of the trithorax (trxG) and Polycomb groups (PcG) are best known for their regulatory functions in Drosophila, where they control homeotic gene expression. Plants and animals are thought to have evolved multicellularity independently. Although homeotic genes control organ identity in both animals and plants, they are unrelated. Despite this fact, several plant homeotic genes are negatively regulated by plant genes similar to the repressors from the animal PcG. However, plant-activating regulators of the trxG have not been characterized. We provide genetic, molecular, functional, and biochemical evidence that an Arabidopsis gene, ATX1, which is similar to the Drosophila trx, regulates floral organ development. The effects are specific: structurally and functionally related flower homeotic genes are under different control. We show that ATX1 is an epigenetic regulator with histone H3K4 methyltransferase activity. This is the first example of this kind of enzyme activity reported in plants, and, in contrast to the Drosophila and the yeast trithorax homologs, ATX1 can methylate in the absence of additional proteins. In its ability to methylate H3K4 as a recombinant protein, ATX1 is similar to the human homolog. ATX1 functions as an activator of homeotic genes, like Trithorax in animal systems. The histone methylating activity of the ATX1-SET domain argues that the molecular basis of these effects is the ability of ATX1 to modify chromatin structure. Our results suggest a conservation of trxG function between the animal and plant kingdoms despite the different structural nature of their targets.

  4. Cloning and characterization of prunus serotina AGAMOUS, a putative flower homeotic gene

    Treesearch

    Xiaomei Liu; Joseph Anderson; Paula Pijut

    2010-01-01

    Members of the AGAMOUS subfamily of MADS-box transcription factors play an important role in regulating the development of reproductive organs in flowering plants. To help understand the mechanism of floral development in black cherry (Prunus serotina), PsAG (a putative flower homeotic identity gene) was isolated...

  5. Homeotic gene regulation: a paradigm for epigenetic mechanisms underlying organismal development.

    PubMed

    Matharu, Navneet K; Dasari, Vasanthi; Mishra, Rakesh K

    2013-01-01

    The organization of eukaryotic genome into chromatin within the nucleus eventually dictates the cell type specific expression pattern of genes. This higher order of chromatin organization is established during development and dynamically maintained throughout the life span. Developmental mechanisms are conserved in bilaterians and hence they have body plan in common, which is achieved by regulatory networks controlling cell type specific gene expression. Homeotic genes are conserved in metazoans and are crucial for animal development as they specify cell type identity along the anterior-posterior body axis. Hox genes are the best studied in the context of epigenetic regulation that has led to significant understanding of the organismal development. Epigenome specific regulation is brought about by conserved chromatin modulating factors like PcG/trxG proteins during development and differentiation. Here we discuss the conserved epigenetic mechanisms relevant to homeotic gene regulation in metazoans.

  6. Floral homeotic genes are targets of gibberellin signaling in flower development.

    PubMed

    Yu, Hao; Ito, Toshiro; Zhao, Yuanxiang; Peng, Jinrong; Kumar, Prakash; Meyerowitz, Elliot M

    2004-05-18

    Gibberellins (GAs) are a class of plant hormones involved in the regulation of flower development in Arabidopsis. The GA-deficient ga1-3 mutant shows retarded growth of all floral organs, especially abortive stamen development that results in complete male sterility. Until now, it has not been clear how GA regulates the late-stage development of floral organs after the establishment of their identities within floral meristems. Various combinations of null mutations of DELLA proteins can gradually rescue floral defects in ga1-3. In particular, the synergistic effect of rga-t2 and rgl2-1 can substantially restore flower development in ga1-3. We find that the transcript levels of floral homeotic genes APETALA3 (AP3), PISTILLATA (PI), and AGAMOUS (AG) are immediately upregulated in young flowers of ga1-3 upon GA treatment. Using a steroid-inducible activation of RGA, we further demonstrated that these floral homeotic genes are transcriptionally repressed by RGA activity in young flowers whereas the expression of LEAFY (LFY) and APETALA1 (AP1) is not substantially affected. In addition, we observed the partial rescue of floral defects in ga1-3 by overexpression of AG. Our results indicate that GA promotes the expression of floral homeotic genes by antagonizing the effects of DELLA proteins, thereby allowing continued flower development.

  7. Interactions between FLORAL ORGAN NUMBER4 and floral homeotic genes in regulating rice flower development.

    PubMed

    Xu, Wei; Tao, Juhong; Chen, Mingjiao; Dreni, Ludovico; Luo, Zhijing; Hu, Yun; Liang, Wanqi; Zhang, Dabing

    2017-01-01

    The floral meristem (FM) is self-maintaining at the early stages of flower development, but it is terminated when a fixed number of floral organs are produced. The FLORAL ORGAN NUMBER4 (FON4; also known as FON2) gene, an ortholog of Arabidopsis CLAVATA3 (CLV3), is required for regulating FM size and determinacy in rice. However, its interactions with floral homeotic genes remain unknown. Here, we report the genetic interactions between FON4 and floral homeotic genes OsMADS15 (an A-class gene), OsMADS16 (also called SUPERWOMAN1, SPW1, a B-class gene), OsMADS3 and OsMADS58 (C-class genes), OsMADS13 (a D-class gene), and OsMADS1 (an E-class gene) during flower development. We observed an additive phenotype in the fon4 double mutant with the OsMADS15 mutant allele dep (degenerative palea). The effect on the organ number of whorl 2 was enhanced in fon4 spw1. Double mutant combinations of fon4 with osmads3, osmads58, osmads13, and osmads1 displayed enhanced defects in FM determinacy and identity, respectively, indicating that FON4 and these genes synergistically control FM activity. In addition, the expression patterns of all the genes besides OsMADS13 had no obvious change in the fon4 mutant. This work reveals how the meristem maintenance gene FON4 genetically interacts with C, D, and E floral homeotic genes in specifying FM activity in monocot rice.

  8. Differences in DNA Binding Specificity of Floral Homeotic Protein Complexes Predict Organ-Specific Target Genes.

    PubMed

    Smaczniak, Cezary; Muiño, Jose M; Chen, Dijun; Angenent, Gerco C; Kaufmann, Kerstin

    2017-08-01

    Floral organ identities in plants are specified by the combinatorial action of homeotic master regulatory transcription factors. However, how these factors achieve their regulatory specificities is still largely unclear. Genome-wide in vivo DNA binding data show that homeotic MADS domain proteins recognize partly distinct genomic regions, suggesting that DNA binding specificity contributes to functional differences of homeotic protein complexes. We used in vitro systematic evolution of ligands by exponential enrichment followed by high-throughput DNA sequencing (SELEX-seq) on several floral MADS domain protein homo- and heterodimers to measure their DNA binding specificities. We show that specification of reproductive organs is associated with distinct binding preferences of a complex formed by SEPALLATA3 and AGAMOUS. Binding specificity is further modulated by different binding site spacing preferences. Combination of SELEX-seq and genome-wide DNA binding data allows differentiation between targets in specification of reproductive versus perianth organs in the flower. We validate the importance of DNA binding specificity for organ-specific gene regulation by modulating promoter activity through targeted mutagenesis. Our study shows that intrafamily protein interactions affect DNA binding specificity of floral MADS domain proteins. Differential DNA binding of MADS domain protein complexes plays a role in the specificity of target gene regulation. © 2017 American Society of Plant Biologists. All rights reserved.

  9. Global identification of target genes regulated by APETALA3 and PISTILLATA floral homeotic gene action.

    PubMed

    Zik, Moriyah; Irish, Vivian F

    2003-01-01

    Identifying the genes regulated by the floral homeotic genes APETALA3 (AP3) and PISTILLATA (PI) is crucial for understanding the molecular mechanisms that lead to petal and stamen formation. We have used microarray analysis to conduct a broad survey of genes whose expression is affected by AP3 and PI activity. DNA microarrays consisting of 9216 Arabidopsis ESTs were screened with probes corresponding to mRNAs from different mutant and transgenic lines that misexpress AP3 and/or PI. The microarray results were further confirmed by RNA gel blot analyses. Our results suggest that AP3 and PI regulate a relatively small number of genes, implying that many genes used in petal and stamen development are not tissue specific and likely have roles in other processes as well. We recovered genes similar to previously identified petal- and stamen-expressed genes as well as genes that were not implicated previously in petal and stamen development. A very low percentage of the genes recovered encoded transcription factors. This finding suggests that AP3 and PI act relatively directly to regulate the genes required for the basic cellular processes responsible for petal and stamen morphogenesis.

  10. Homeotic Genes and the ABCDE Model for Floral Organ Formation in Wheat.

    PubMed

    Murai, Koji

    2013-06-25

    Floral organ formation has been the subject of intensive study for over 20 years, particularly in the model dicot species Arabidopsis thaliana. These studies have led to the establishment of a general model for the development of floral organs in higher plants, the so-called ABCDE model, in which floral whorl-specific combinations of class A, B, C, D, or E genes specify floral organ identity. In Arabidopsis, class A, B, C, D, E genes encode MADS-box transcription factors except for the class A gene APETALA2. Mutation of these genes induces floral organ homeosis. In this review, I focus on the roles of these homeotic genes in bread wheat (Triticum aestivum), particularly with respect to the ABCDE model. Pistillody, the homeotic transformation of stamens into pistil-like structures, occurs in cytoplasmic substitution (alloplasmic) wheat lines that have the cytoplasm of the related wild species Aegilops crassa. This phenomenon is a valuable tool for analysis of the wheat ABCDE model. Using an alloplasmic line, the wheat ortholog of DROOPING LEAF (TaDL), a member of the YABBY gene family, has been shown to regulate pistil specification. Here, I describe the current understanding of the ABCDE model for floral organ formation in wheat.

  11. Homeotic Genes and the ABCDE Model for Floral Organ Formation in Wheat

    PubMed Central

    Murai, Koji

    2013-01-01

    Floral organ formation has been the subject of intensive study for over 20 years, particularly in the model dicot species Arabidopsis thaliana. These studies have led to the establishment of a general model for the development of floral organs in higher plants, the so-called ABCDE model, in which floral whorl-specific combinations of class A, B, C, D, or E genes specify floral organ identity. In Arabidopsis, class A, B, C, D, E genes encode MADS-box transcription factors except for the class A gene APETALA2. Mutation of these genes induces floral organ homeosis. In this review, I focus on the roles of these homeotic genes in bread wheat (Triticum aestivum), particularly with respect to the ABCDE model. Pistillody, the homeotic transformation of stamens into pistil-like structures, occurs in cytoplasmic substitution (alloplasmic) wheat lines that have the cytoplasm of the related wild species Aegilops crassa. This phenomenon is a valuable tool for analysis of the wheat ABCDE model. Using an alloplasmic line, the wheat ortholog of DROOPING LEAF (TaDL), a member of the YABBY gene family, has been shown to regulate pistil specification. Here, I describe the current understanding of the ABCDE model for floral organ formation in wheat. PMID:27137382

  12. Developmental robustness by obligate interaction of class B floral homeotic genes and proteins.

    PubMed

    Lenser, Thorsten; Theissen, Günter; Dittrich, Peter

    2009-01-01

    DEF-like and GLO-like class B floral homeotic genes encode closely related MADS-domain transcription factors that act as developmental switches involved in specifying the identity of petals and stamens during flower development. Class B gene function requires transcriptional upregulation by an autoregulatory loop that depends on obligate heterodimerization of DEF-like and GLO-like proteins. Because switch-like behavior of gene expression can be displayed by single genes already, the functional relevance of this complex circuitry has remained enigmatic. On the basis of a stochastic in silico model of class B gene and protein interactions, we suggest that obligate heterodimerization of class B floral homeotic proteins is not simply the result of neutral drift but enhanced the robustness of cell-fate organ identity decisions in the presence of stochastic noise. This finding strongly corroborates the view that the appearance of this regulatory mechanism during angiosperm phylogeny led to a canalization of flower development and evolution.

  13. Head and tail development of the Drosophila embryo involves spalt, a novel homeotic gene

    PubMed Central

    Jürgens, Gerd

    1988-01-01

    Mutations in spalt (sal), a novel homeotic gene on the second chromosome of Drosophila, cause opposite transformations in two subterminal regions of the embryo: posterior head segments are transformed into anterior thoracic structures and anterior tail segments are transformed into posterior abdominal structures. The embryonic phenotypes of double mutants for sal and various Antennapedia (ANT-C) or bithorax (BX-C) genes indicate that sal acts independently of the hierarchical order of the latter gene complexes. Trans-regulatory gene mutations causing ectopic expression of ANT-C and BX-C genes do not change the realms of sal action. It is proposed that the region-specific action of the sal gene primarily promotes head as opposed to trunk development, while the BX-C gene AbdB distinguishes tail from head. Images PMID:16453820

  14. Structural complexity and evolutionary conservation of the Drosophila homeotic gene proboscipedia.

    PubMed Central

    Cribbs, D L; Pultz, M A; Johnson, D; Mazzulla, M; Kaufman, T C

    1992-01-01

    Mutations of the homeotic gene proboscipedia (pb) of Drosophila cause striking transformations of the adult mouthparts, to legs or antennae. We report here an analysis of the gene structure of pb. Coding sequences across a 34 kb interval yield, by alternative splicing, four identified mRNA forms which differ immediately upstream of the homeobox. As a consequence, the homeodomain is expected to reside in four different contexts in the predicted protein isoforms. Mammalian homologs of pb, human HOX-2H and murine Hox-2.8, were identified based on the similarities of their homeodomains (95% identity) and several other conserved motifs. Examination of a collection of pb mutant alleles with antisera directed against the N-terminal region, the center or the C-terminal region of the protein showed that, surprisingly, several partial loss-of-function pb alleles appear to generate partially functional proteins truncated at their C-termini. This suggests that a significant portion of the protein contributes quantitatively to pb function, but is partially dispensable. Finally, evolutionary considerations suggest that pb may be one of several ancient genes which preceded the process yielding the modern homeotic gene complexes. Images PMID:1348688

  15. Developmental and molecular analysis of Deformed; a homeotic gene controlling Drosophila head development

    PubMed Central

    Regulski, Michael; McGinnis, Nadine; Chadwick, Robin; McGinnis, William

    1987-01-01

    The characteristic morphology of many elements of the Drosophila body plan is crucially dependent upon the proper spatial expression of homeotic selector genes. The Deformed locus, which we isolated by virtue of its homology to the homeo box, is a candidate for a homeotic selector in the head region of the developing embryo. Here we show that null mutants of Deformed result in a loss of pattern elements derived from the maxillary and mandibular segments, and a duplication of a cuticular element of the larval head skeleton. Molecular analysis of the locus shows that Dfd transcripts are encoded in five exons distributed over 11 kb. The major transcript of 2.8 kb contains a 1758-bp open reading frame that would translate to yield a 63.5-kd protein containing a homeo domain and conspicuous regions of monotonic amino acid sequences. The Dfd protein exhibits extensive homology to a protein encoded by a Xenopus homeo box gene, Xhox 1A, suggesting that the Xenopus gene is the frog homologue of Dfd. ImagesFig. 1.Fig. 2.Fig. 3.Fig. 5. PMID:16453752

  16. Functional conservation and diversification of class E floral homeotic genes in rice (Oryza sativa).

    PubMed

    Cui, Rongfeng; Han, Jiakun; Zhao, Suzhen; Su, Kunmei; Wu, Feng; Du, Xiaoqiu; Xu, Qijiang; Chong, Kang; Theissen, Günter; Meng, Zheng

    2010-03-01

    Mutant analyses in different eudicotyledonous flowering plants demonstrated that SEPALLATA-like MADS-box genes are required for the specification of sepals, petals, stamens and carpels, and for floral determinacy, thus defining class E floral organ identity genes. SEP-like genes encode MADS-domain transcription factors and constitute an angiosperm-specific gene clade whose members show remarkably different degrees of redundancy and sub-functionalization within eudicots. To better understand the evolutionary dynamics of SEP-like genes throughout the angiosperms we have knocked down SEP-like genes of rice (Oryza sativa), a distant relative of eudicots within the flowering plants. Plants affected in both OsMADS7 and OsMADS8 show severe phenotypes including late flowering, homeotic changes of lodicules, stamens and carpels into palea/lemma-like organs, and a loss of floral determinacy. Simultaneous knockdown of the four rice SEP-like genes OsMADS1, OsMADS5, OsMADS7 and OsMADS8, leads to homeotic transformation of all floral organs except the lemma into leaf-like organs. This mimics the phenotype observed with the sep1 sep2 sep3 sep4 quadruple mutant of Arabidopsis. Detailed analyses of the spatial and temporal mRNA expression and protein interaction patterns corresponding to the different rice SEP-like genes show strong similarities, but also gene-specific differences. These findings reveal conservation of SEP-like genes in specifying floral determinacy and organ identities since the separation of eudicots and monocots about 150 million years ago. However, they indicate also monocot-specific neo- and sub-functionalization events and hence underscore the evolutionary dynamics of SEP-like genes. Moreover, our findings corroborate the view that the lodicules of grasses are homologous to eudicot petals.

  17. Downstream of homeotic genes: in the heart of Hox function.

    PubMed

    Monier, Bruno; Tevy, Maria Florencia; Perrin, Laurent; Capovilla, Maria; Sémériva, Michel

    2007-01-01

    A functional organ is constituted of diverse cell types. Each one occupies a distinct position and is associated to specific morphological and physiological functions. The identification of the genetic programs controlling these elaborated and highly precise features of organogenesis is crucial to understand how a mature organ works under normal conditions, and how pathologies can develop. Recently, a number of studies have reported a critical role for Hox genes in one example of organogenesis: cardiogenesis in Drosophila. Beyond the interest in understanding the molecular basis of functional cardiogenesis, this system might provide a model for proposing new paradigms of how Hox genes achieve their action throughout development.

  18. The role of homeotic genes in determining the segmental pattern of chordotonal organs in Drosophila.

    PubMed

    Wong, Darren C C; Merritt, David J

    2002-01-01

    The homeotic genes are instrumental in establishing segment-specific characteristics. In Drosophila embryos there is ample evidence that the homeotic genes are involved in establishing the differences in the pattern of sense organs between segments. The chordotonal organs are compound sense organs made up of several stretch receptive sensilla. A set of serially homologous chordotonal organs, lch3 in the 1st thoracic segment, dch3 in the 2nd and 3rd thoracic segments and lch5 in abdominal segments 1 to 7, is composed of different numbers of sensilla with different positions and orientations. Here we examine this set of sense organs and a companion set, vchA/B and veh1, in the wild type and mutants for Sexcombs reduced, Antennapedia, Ultrabithorax, and abdominal-A, using immunostaining. Mutant phenotypes indicate that Ultrabithorax and abdominal-A in particular influence the formation of these sense organs. Differential expression of abdominal-A and Ultrabithorax within compartments of individual parasegments can precisely modulate the types of sense organs that will arise from a segment.

  19. Vertebrate GAGA factor associated insulator elements demarcate homeotic genes in the HOX clusters.

    PubMed

    Srivastava, Surabhi; Puri, Deepika; Garapati, Hita Sony; Dhawan, Jyotsna; Mishra, Rakesh K

    2013-04-22

    Hox genes impart segment identity to body structures along the anterior-posterior axis and are crucial for the proper development of all organisms. Multiple regulatory elements, best defined in Drosophila melanogaster, ensure that Hox expression patterns follow the spatial and temporal colinearity reflected in their tight genomic organization. However, the precise mechanisms that regulate colinear patterns of Hox gene expression remain unclear, especially in higher vertebrates where it is not fully determined how the distinct activation domains of the tightly clustered Hox genes are defined independently of each other. Here, we report the identification of a large number of novel cis-elements at mammalian Hox clusters that can help in regulating their precise expression pattern. We have identified DNA elements at all four murine Hox clusters that show poor association with histone H3 in chromatin immunoprecipitation (ChIP)-chip tiling arrays. The majority of these elements lie in the intergenic regions segregating adjacent Hox genes; we demonstrate that they possess efficient enhancer-blocking activity in mammalian cells. Further, we find that these histone-free intergenic regions bear GA repeat motifs and associate with the vertebrate homolog of the GAGA binding boundary factor. This suggests that they can act as GAGA factor-dependent chromatin boundaries that create independent domains, insulating each Hox gene from the influence of neighboring regulatory elements. Our results reveal a large number of potential regulatory elements throughout the murine Hox clusters. We further demarcate the precise location of several novel cis-elements bearing chromatin boundary activity that appear to segregate successive Hox genes. This reflects a pattern reminiscent of the organization of homeotic genes in Drosophila, where such regulatory elements have been characterized. Our findings thus provide new insights into the regulatory processes and evolutionarily conserved

  20. Interactions of OsMADS1 with Floral Homeotic Genes in Rice Flower Development.

    PubMed

    Hu, Yun; Liang, Wanqi; Yin, Changsong; Yang, Xuelian; Ping, Baozhe; Li, Anxue; Jia, Ru; Chen, Mingjiao; Luo, Zhijing; Cai, Qiang; Zhao, Xiangxiang; Zhang, Dabing; Yuan, Zheng

    2015-09-01

    During reproductive development, rice plants develop unique flower organs which determine the final grain yield. OsMADS1, one of SEPALLATA-like MADS-box genes, has been unraveled to play critical roles in rice floral organ identity specification and floral meristem determinacy. However, the molecular mechanisms underlying interactions of OsMADS1 with other floral homeotic genes in regulating flower development remains largely elusive. In this work, we studied the genetic interactions of OsMADS1 with B-, C-, and D-class genes along with physical interactions among their proteins. We show that the physical and genetic interactions between OsMADS1 and OsMADS3 are essential for floral meristem activity maintenance and organ identity specification; while OsMADS1 physically and genetically interacts with OsMADS58 in regulating floral meristem determinacy and suppressing spikelet meristem reversion. We provided important genetic evidence to support the neofunctionalization of two rice C-class genes (OsMADS3 and OsMADS58) during flower development. Gene expression profiling and quantitative RT-PCR analyses further revealed that OsMADS1 affects the expression of many genes involved in floral identity and hormone signaling, and chromatin immunoprecipitation (ChIP)-PCR assay further demonstrated that OsMADS17 is a direct target gene of OsMADS1. Taken together, these results reveal that OsMADS1 has diversified regulatory functions in specifying rice floral organ and meristem identity, probably through its genetic and physical interactions with different floral homeotic regulators. Copyright © 2015 The Author. Published by Elsevier Inc. All rights reserved.

  1. The structure and expression of a hybrid homeotic gene

    PubMed Central

    Rowe, Annie; Akam, Michael

    1988-01-01

    We describe the structure and expression of an exceptional bithorax complex mutation, C1. This deletion mutation removes major portions of both the Ultrabithorax (Ubx) and abdominal-A (abd-A) protein coding regions, yet retains many of the functions normally executed by these genes. We show that the ends of the C1 deletion map to analogous positions within the Ubx and abd-A transcription units, and that the deletion chromosome gives rise to a set of novel fusion transcripts that may encode hybrid abd-A/Ubx proteins. These fusion products are transcribed from the abd-A promoter, but exhibit a novel spatial pattern of expression that combines aspects of the normal Ubx and abd-A distributions. This pattern provides evidence for the existence of regulatory elements located in the 3' region of the Ubx transcription unit that can act on the abd-A promoter at a distance of at least 20 kb. Images PMID:16453833

  2. Homeotic genes and the arthropod head: Expression patterns of the labial, proboscipedia, and Deformed genes in crustaceans and insects

    PubMed Central

    Abzhanov, Arhat; Kaufman, Thomas C.

    1999-01-01

    cDNA fragments of the homologues of the Drosophila head homeotic genes labial (lab), proboscipedia (pb), and Deformed (Dfd) have been isolated from the crustacean Porcellio scaber. Because the accumulation domains of the head homeotic complex (Hox) genes had not been previously reported for crustaceans, we studied the expression patterns of these genes in P. scaber embryos by using in situ hybridization. The P. scaber lab homologue is expressed in the developing second antennal segment and its appendages. This expression domain in crustaceans and in the homologous intercalary segment of insects suggests that the lab gene specified this metamere in the last common ancestor of these two groups. The expression domain of the P. scaber pb gene is in the posterior part of the second antennal segment. This domain, in contrast to that in insects, is colinear with the domains of other head genes in P. scaber, and it differs from the insect pb gene expression domain in the posterior mouthparts, suggesting that the insect and crustacean patterns evolved independently from a broader ancestral domain similar to that found in modern chelicerates. P. scaber Dfd is expressed in the mandibular segment and paragnaths (a pair of ventral mouthpart structures associated with the stomodeum) and differs from insects, where expression is in the mandibular and maxillary segments. Thus, like pb, Dfd shows a divergent Hox gene deployment. We conclude that homologous structures of the mandibulate head display striking differences in their underlying developmental programs related to Hox gene expression. PMID:10468590

  3. SET1A/COMPASS and shadow enhancers in the regulation of homeotic gene expression.

    PubMed

    Cao, Kaixiang; Collings, Clayton K; Marshall, Stacy A; Morgan, Marc A; Rendleman, Emily J; Wang, Lu; Sze, Christie C; Sun, Tianjiao; Bartom, Elizabeth T; Shilatifard, Ali

    2017-04-15

    The homeotic (Hox) genes are highly conserved in metazoans, where they are required for various processes in development, and misregulation of their expression is associated with human cancer. In the developing embryo, Hox genes are activated sequentially in time and space according to their genomic position within Hox gene clusters. Accumulating evidence implicates both enhancer elements and noncoding RNAs in controlling this spatiotemporal expression of Hox genes, but disentangling their relative contributions is challenging. Here, we identify two cis-regulatory elements (E1 and E2) functioning as shadow enhancers to regulate the early expression of the HoxA genes. Simultaneous deletion of these shadow enhancers in embryonic stem cells leads to impaired activation of HoxA genes upon differentiation, while knockdown of a long noncoding RNA overlapping E1 has no detectable effect on their expression. Although MLL/COMPASS (complex of proteins associated with Set1) family of histone methyltransferases is known to activate transcription of Hox genes in other contexts, we found that individual inactivation of the MLL1-4/COMPASS family members has little effect on early Hox gene activation. Instead, we demonstrate that SET1A/COMPASS is required for full transcriptional activation of multiple Hox genes but functions independently of the E1 and E2 cis-regulatory elements. Our results reveal multiple regulatory layers for Hox genes to fine-tune transcriptional programs essential for development. © 2017 Cao et al.; Published by Cold Spring Harbor Laboratory Press.

  4. HUA ENHANCER2, a putative DExH-box RNA helicase, maintains homeotic B and C gene expression in Arabidopsis

    PubMed Central

    Western, Tamara L.; Cheng, Yulan; Liu, Jun; Chen, Xuemei

    2016-01-01

    SUMMARY Reproductive organ identity in Arabidopsis is controlled by the B, C and SEPALLATA classes of floral homeotic genes. We have identified a recessive mutation in a novel gene, HUA ENHANCER2, which, when combined with mutations in two weak class C genes, HUA1 and HUA2, leads to the production of third whorl sepal-petal-stamens and fourth whorl sepal-carpels. Quadruple mutant analysis and in situ localization of A, B, C and SEPALLATA floral homeotic RNAs suggest that HUA ENHANCER2 is required for the maintenance of B and C gene expression in the reproductive whorls. In addition to its role in floral homeotic gene expression, HUA ENHANCER2 is required for normal spacing and number of perianth organ primordia. We show that HUA ENHANCER2 encodes a putative DExH-box RNA helicase that is expressed in specific patterns in the inflorescence meristem and developing flowers. As a possible ortholog of the yeast exosome-associated protein, Dob1p (Mtr4p), HUA ENHANCER2 may affect floral organ spacing and identity through the regulation of protein synthesis or mRNA degradation. Therefore, our studies on HUA ENHANCER2 not only demonstrate that B and C gene expression is established and maintained separately, but also implicate the existence of post-transcriptional mechanisms in the maintenance of B and C gene expression. PMID:11923195

  5. A novel MADS-box gene subfamily with a sister-group relationship to class B floral homeotic genes.

    PubMed

    Becker, A; Kaufmann, K; Freialdenhoven, A; Vincent, C; Li, M-A; Saedler, H; Theissen, G

    2002-02-01

    Class B floral homeotic genes specify the identity of petals and stamens during the development of angiosperm flowers. Recently, putative orthologs of these genes have been identified in different gymnosperms. Together, these genes constitute a clade, termed B genes. Here we report that diverse seed plants also contain members of a hitherto unknown sister clade of the B genes, termed B(sister) (B(s)) genes. We have isolated members of the B(s) clade from the gymnosperm Gnetum gnemon, the monocotyledonous angiosperm Zea mays and the eudicots Arabidopsis thaliana and Antirrhinum majus. In addition, MADS-box genes from the basal angiosperm Asarum europaeum and the eudicot Petunia hybrida were identified as B(s) genes. Comprehensive expression studies revealed that B(s) genes are mainly transcribed in female reproductive organs (ovules and carpel walls). This is in clear contrast to the B genes, which are predominantly expressed in male reproductive organs (and in angiosperm petals). Our data suggest that the B(s) genes played an important role during the evolution of the reproductive structures in seed plants. The establishment of distinct B and B(s) gene lineages after duplication of an ancestral gene may have accompanied the evolution of male microsporophylls and female megasporophylls 400-300 million years ago. During flower evolution, expression of B(s) genes diversified, but the focus of expression remained in female reproductive organs. Our findings imply that a clade of highly conserved close relatives of class B floral homeotic genes has been completely overlooked until recently and awaits further evaluation of its developmental and evolutionary importance. Electronic supplementary material to this paper can be obtained by using the Springer Link server located at http://dx.doi.org/10.1007/s00438-001-0615-8.

  6. Targeted disruption of Hotair leads to homeotic transformation and gene derepression.

    PubMed

    Li, Lingjie; Liu, Bo; Wapinski, Orly L; Tsai, Miao-Chih; Qu, Kun; Zhang, Jiajing; Carlson, Jeff C; Lin, Meihong; Fang, Fengqin; Gupta, Rajnish A; Helms, Jill A; Chang, Howard Y

    2013-10-17

    Long noncoding RNAs (lncRNAs) are thought to be prevalent regulators of gene expression, but the consequences of lncRNA inactivation in vivo are mostly unknown. Here, we show that targeted deletion of mouse Hotair lncRNA leads to derepression of hundreds of genes, resulting in homeotic transformation of the spine and malformation of metacarpal-carpal bones. RNA sequencing and conditional inactivation reveal an ongoing requirement of Hotair to repress HoxD genes and several imprinted loci such as Dlk1-Meg3 and Igf2-H19 without affecting imprinting choice. Hotair binds to both Polycomb repressive complex 2, which methylates histone H3 at lysine 27 (H3K27), and Lsd1 complex, which demethylates histone H3 at lysine 4 (H3K4) in vivo. Hotair inactivation causes H3K4me3 gain and, to a lesser extent, H3K27me3 loss at target genes. These results reveal the function and mechanisms of Hotair lncRNA in enforcing a silent chromatin state at Hox and additional genes. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

  7. Targeted disruption of Hotair leads to homeotic transformation and gene de-repression

    PubMed Central

    Li, Lingjie; Liu, Bo; Wapinski, Orly L.; Tsai, Miao-Chih; Qu, Kun; Zhang, Jiajing; Carlson, Jeff C.; Lin, Meihong; Fang, Fengqin; Gupta, Rajnish A.; Helms, Jill A.; Chang, Howard Y.

    2014-01-01

    SUMMARY Long noncoding RNAs (lncRNAs) are thought to be prevalent regulators of gene expression, but the consequences of lncRNA inactivation in vivo are mostly unknown. Here we show that targeted deletion of mouse Hotair lncRNA leads to de-repression of hundreds of genes, resulting in homeotic transformation of the spine and malformation of metacarpal-carpal bones. RNA-seq and conditional inactivation reveal an ongoing requirement of Hotair to repress HoxD genes and several imprinted loci such as Dlk1-Meg3 and Igf2-H19, without affecting imprinting choice. Hotair binds to both Polycomb repressive complex 2 that methylates histone H3 at lysine 27 (H3K27) and Lsd1 complex that demethylates histone H3 at lysine 4 (H3K4) in vivo. Hotair inactivation causes H3K4me3 gain and, to a lesser extent, H3K27me3 loss at target genes. These results reveal the function and mechanisms of Hotair lncRNA to enforce silent chromatin state at Hox and additional genes. PMID:24075995

  8. Identification of planarian homeobox sequences indicates the antiquity of most Hox/homeotic gene subclasses.

    PubMed Central

    Balavoine, G; Telford, M J

    1995-01-01

    The homeotic gene complex (HOM-C) is a cluster of genes involved in the anteroposterior axial patterning of animal embryos. It is composed of homeobox genes belonging to the Hox/HOM superclass. Originally discovered in Drosophila, Hox/HOM genes have been identified in organisms as distantly related as arthropods, vertebrates, nematodes, and cnidarians. Data obtained in parallel from the organization of the complex, the domains of gene expression during embryogenesis, and phylogenetic relationships allow the subdivision of the Hox/HOM superclass into five classes (lab, pb/Hox3, Dfd, Antp, and Abd-B) that appeared early during metazoan evolution. We describe a search for homologues of these genes in platyhelminths, triploblast metazoans emerging as an outgroup to the great coelomate ensemble. A degenerate PCR screening for Hox/HOM homeoboxes in three species of triclad planarians has revealed 10 types of Antennapedia-like genes. The homeobox-containing sequences of these PCR fragments allowed the amplification of the homeobox-coding exons for five of these genes in the species Polycelis nigra. A phylogenetic analysis shows that two genes are clear orthologues of Drosophila labial, four others are members of a Dfd/Antp superclass, and a seventh gene, although more difficult to classify with certainty, may be related to the pb/Hox3 class. Together with previously identified Hox/HOM genes in other flatworms, our analyses demonstrate the existence of an elaborate family of Hox/HOM genes in the ancestor of all triploblast animals. Images Fig. 4 PMID:7638172

  9. Regulatory elements of the floral homeotic gene AGAMOUS identified by phylogenetic footprinting and shadowing.

    SciTech Connect

    Hong, R. L., Hamaguchi, L., Busch, M. A., and Weigel, D.

    2003-06-01

    OAK-B135 In Arabidopsis thaliana, cis-regulatory sequences of the floral homeotic gene AGAMOUS (AG) are located in the second intron. This 3 kb intron contains binding sites for two direct activators of AG, LEAFY (LFY) and WUSCHEL (WUS), along with other putative regulatory elements. We have used phylogenetic footprinting and the related technique of phylogenetic shadowing to identify putative cis-regulatory elements in this intron. Among 29 Brassicaceae, several other motifs, but not the LFY and WUS binding sites previously identified, are largely invariant. Using reporter gene analyses, we tested six of these motifs and found that they are all functionally important for activity of AG regulatory sequences in A. thaliana. Although there is little obvious sequence similarity outside the Brassicaceae, the intron from cucumber AG has at least partial activity in A. thaliana. Our studies underscore the value of the comparative approach as a tool that complements gene-by-gene promoter dissection, but also highlight that sequence-based studies alone are insufficient for a complete identification of cis-regulatory sites.

  10. Regulatory Elements of the Floral Homeotic Gene AGAMOUS Identified by Phylogenetic Footprinting and ShadowingW⃞

    PubMed Central

    Hong, Ray L.; Hamaguchi, Lynn; Busch, Maximilian A.; Weigel, Detlef

    2003-01-01

    In Arabidopsis thaliana, cis-regulatory sequences of the floral homeotic gene AGAMOUS (AG) are located in the second intron. This 3-kb intron contains binding sites for two direct activators of AG, LEAFY (LFY) and WUSCHEL (WUS), along with other putative regulatory elements. We have used phylogenetic footprinting and the related technique of phylogenetic shadowing to identify putative cis-regulatory elements in this intron. Among 29 Brassicaceae species, several other motifs, but not the LFY and WUS binding sites identified previously, are largely invariant. Using reporter gene analyses, we tested six of these motifs and found that they are all functionally important for the activity of AG regulatory sequences in A. thaliana. Although there is little obvious sequence similarity outside the Brassicaceae, the intron from cucumber AG has at least partial activity in A. thaliana. Our studies underscore the value of the comparative approach as a tool that complements gene-by-gene promoter dissection but also demonstrate that sequence-based studies alone are insufficient for a complete identification of cis-regulatory sites. PMID:12782724

  11. Isolation and characterization of a floral homeotic gene in Fraxinus nigra causing earlier flowering and homeotic alterations in transgenic Arabidopsis

    Treesearch

    Jun Hyung Lee; Paula M. Pijut

    2017-01-01

    Reproductive sterility, which can be obtained by manipulating floral organ identity genes, is an important tool for gene containment of genetically engineered trees. In Arabidopsis, AGAMOUS (AG) is the only C-class gene responsible for both floral meristem determinacy and floral organ identity, and its mutations produce...

  12. Tracing the evolution of the floral homeotic B- and C-function genes through genome synteny.

    PubMed

    Causier, Barry; Castillo, Rosa; Xue, Yongbiao; Schwarz-Sommer, Zsuzsanna; Davies, Brendan

    2010-11-01

    The evolution of the floral homeotic genes has been characterized using phylogenetic and functional studies. It is possible to enhance these studies by comparing gene content and order between species to determine the evolutionary history of the regulatory genes. Here, we use a synteny-based approach to trace the evolution of the floral B- and C-function genes that are required for specification of the reproductive organs. Consistent with previous phylogenetic studies, we show that the euAP3-TM6 split occurred after the monocots and dicots diverged. The Arabidopsis TM6 and papaya euAP3 genes are absent from the respective genomes, and we have detected loci from which these genes were lost. These data indicate that either the TM6 or the euAP3 lineage genes can be lost without detriment to flower development. In contrast, PI is essential for male reproductive organ development; yet, contrary to predictions, complex genomic rearrangements have resulted in almost complete breakdown of synteny at the PI locus. In addition to showing the evolution of B-function genes through the prediction of ancestral loci, similar reconstructions reveal the origins of the C-function AG and PLE lineages in dicots, and show the shared ancestry with the monocot C-function genes. During our studies, we found that transposable elements (TEs) present in sequenced Antirrhinum genomic clones limited comparative studies. A pilot survey of the Antirrhinum data revealed that gene-rich regions contain an unusually high degree of TEs of very varied types, which will be an important consideration for future genome sequencing efforts.

  13. Tracing the Evolution of the Floral Homeotic B- and C-Function Genes through Genome Synteny

    PubMed Central

    Causier, Barry; Castillo, Rosa; Xue, Yongbiao; Schwarz-Sommer, Zsuzsanna; Davies, Brendan

    2010-01-01

    The evolution of the floral homeotic genes has been characterized using phylogenetic and functional studies. It is possible to enhance these studies by comparing gene content and order between species to determine the evolutionary history of the regulatory genes. Here, we use a synteny-based approach to trace the evolution of the floral B- and C-function genes that are required for specification of the reproductive organs. Consistent with previous phylogenetic studies, we show that the euAP3–TM6 split occurred after the monocots and dicots diverged. The Arabidopsis TM6 and papaya euAP3 genes are absent from the respective genomes, and we have detected loci from which these genes were lost. These data indicate that either the TM6 or the euAP3 lineage genes can be lost without detriment to flower development. In contrast, PI is essential for male reproductive organ development; yet, contrary to predictions, complex genomic rearrangements have resulted in almost complete breakdown of synteny at the PI locus. In addition to showing the evolution of B-function genes through the prediction of ancestral loci, similar reconstructions reveal the origins of the C-function AG and PLE lineages in dicots, and show the shared ancestry with the monocot C-function genes. During our studies, we found that transposable elements (TEs) present in sequenced Antirrhinum genomic clones limited comparative studies. A pilot survey of the Antirrhinum data revealed that gene-rich regions contain an unusually high degree of TEs of very varied types, which will be an important consideration for future genome sequencing efforts. PMID:20566474

  14. A cucumber DELLA homolog CsGAIP may inhibit staminate development through transcriptional repression of B class floral homeotic genes.

    PubMed

    Zhang, Yan; Liu, Bin; Yang, Sen; An, Jingbo; Chen, Chunhua; Zhang, Xiaolan; Ren, Huazhong

    2014-01-01

    In hermaphroditic Arabidopsis, the phytohormone gibberellin (GA) stimulates stamen development by opposing the DELLA repression of B and C classes of floral homeotic genes. GA can promote male flower formation in cucumber (Cucumis sativus L.), a typical monoecious vegetable with unisexual flowers, and the molecular mechanism remains unknown. Here we characterized a DELLA homolog CsGAIP in cucumber, and we found that CsGAIP is highly expressed in stem and male flower buds. In situ hybridization showed that CsGAIP is greatly enriched in the stamen primordia, especially during the hermaphrodite stage of flower development. Further, CsGAIP protein is located in nucleus. CsGAIP can partially rescue the plant height, stamen development and fertility phenotypes of Arabidopsis rga-24/gai-t6 mutant, and ectopic expression of CsGAIP in wide-type Arabidopsis results in reduced number of stamens and decreased transcription of B class floral homeotic genes APETALA3 (AP3) and PISTILLATA (PI). Our data suggest that monoecious CsGAIP may inhibit staminate development through transcriptional repression of B class floral homeotic genes in Arabidopsis.

  15. A Cucumber DELLA Homolog CsGAIP May Inhibit Staminate Development through Transcriptional Repression of B Class Floral Homeotic Genes

    PubMed Central

    Zhang, Yan; Liu, Bin; Yang, Sen; An, Jingbo; Chen, Chunhua; Zhang, Xiaolan; Ren, Huazhong

    2014-01-01

    In hermaphroditic Arabidopsis, the phytohormone gibberellin (GA) stimulates stamen development by opposing the DELLA repression of B and C classes of floral homeotic genes. GA can promote male flower formation in cucumber (Cucumis sativus L.), a typical monoecious vegetable with unisexual flowers, and the molecular mechanism remains unknown. Here we characterized a DELLA homolog CsGAIP in cucumber, and we found that CsGAIP is highly expressed in stem and male flower buds. In situ hybridization showed that CsGAIP is greatly enriched in the stamen primordia, especially during the hermaphrodite stage of flower development. Further, CsGAIP protein is located in nucleus. CsGAIP can partially rescue the plant height, stamen development and fertility phenotypes of Arabidopsis rga-24/gai-t6 mutant, and ectopic expression of CsGAIP in wide-type Arabidopsis results in reduced number of stamens and decreased transcription of B class floral homeotic genes APETALA3 (AP3) and PISTILLATA (PI). Our data suggest that monoecious CsGAIP may inhibit staminate development through transcriptional repression of B class floral homeotic genes in Arabidopsis. PMID:24632777

  16. Regulatory Regions of the Homeotic Gene Proboscipedia Are Sensitive to Chromosomal Pairing

    PubMed Central

    Kapoun, A. M.; Kaufman, T. C.

    1995-01-01

    We have identified regulatory regions of the homeotic gene proboscipedia that are capable of repressing a linked white minigene in a manner that is sensitive to chromosomal pairing. Normally, the eye color of transformants containing white in a P-element vector is affected by the number of copies of the transgene; homozygous flies have darker eyes than heterozygotes. However, we found that flies homozygous for select pb DNA-containing transgenes had lighter eyes than heterozygotes. Several pb DNA fragments are capable of causing this pairing sensitive (PS) negative regulation of white. Two fragments in the upstream DNA of pb, 0.58 and 0.98 kb, are PS; additionally, two PS sites are located in the second intron, including a 0.5-kb region and 49-bp sequence. This phenotype is not observed when two PS sites are located at different chromosomal insertion sites (in trans-heterozygous transgenic animals), indicating that the pb-DNA-mediated repression of white is dependent on the pairing or proximity of the PS regions. The observed phenomenon is similar to transvection in which certain alleles of a gene can complement each other, but only when homologous chromosomes are paired. Interestingly, the intronic PS regions contain positive regulatory sequences for pb, whereas the upstream PS sites contain pb negative regulatory elements. PMID:7498743

  17. Functional Evolution of cis-Regulatory Modules at a Homeotic Gene in Drosophila

    PubMed Central

    Schiller, Benjamin J.; Bae, Esther; Tran, Diana A.; Shur, Andrey S.; Allen, John M.; Rau, Christoph; Bender, Welcome; Fisher, William W.; Celniker, Susan E.; Drewell, Robert A.

    2009-01-01

    It is a long-held belief in evolutionary biology that the rate of molecular evolution for a given DNA sequence is inversely related to the level of functional constraint. This belief holds true for the protein-coding homeotic (Hox) genes originally discovered in Drosophila melanogaster. Expression of the Hox genes in Drosophila embryos is essential for body patterning and is controlled by an extensive array of cis-regulatory modules (CRMs). How the regulatory modules functionally evolve in different species is not clear. A comparison of the CRMs for the Abdominal-B gene from different Drosophila species reveals relatively low levels of overall sequence conservation. However, embryonic enhancer CRMs from other Drosophila species direct transgenic reporter gene expression in the same spatial and temporal patterns during development as their D. melanogaster orthologs. Bioinformatic analysis reveals the presence of short conserved sequences within defined CRMs, representing gap and pair-rule transcription factor binding sites. One predicted binding site for the gap transcription factor KRUPPEL in the IAB5 CRM was found to be altered in Superabdominal (Sab) mutations. In Sab mutant flies, the third abdominal segment is transformed into a copy of the fifth abdominal segment. A model for KRUPPEL-mediated repression at this binding site is presented. These findings challenge our current understanding of the relationship between sequence evolution at the molecular level and functional activity of a CRM. While the overall sequence conservation at Drosophila CRMs is not distinctive from neighboring genomic regions, functionally critical transcription factor binding sites within embryonic enhancer CRMs are highly conserved. These results have implications for understanding mechanisms of gene expression during embryonic development, enhancer function, and the molecular evolution of eukaryotic regulatory modules. PMID:19893611

  18. Floral homeotic C function genes repress specific B function genes in the carpel whorl of the basal eudicot California poppy (Eschscholzia californica).

    PubMed

    Yellina, Aravinda L; Orashakova, Svetlana; Lange, Sabrina; Erdmann, Robert; Leebens-Mack, Jim; Becker, Annette

    2010-12-01

    The floral homeotic C function gene AGAMOUS (AG) confers stamen and carpel identity and is involved in the regulation of floral meristem termination in Arabidopsis. Arabidopsis ag mutants show complete homeotic conversions of stamens into petals and carpels into sepals as well as indeterminacy of the floral meristem. Gene function analysis in model core eudicots and the monocots rice and maize suggest a conserved function for AG homologs in angiosperms. At the same time gene phylogenies reveal a complex history of gene duplications and repeated subfunctionalization of paralogs. EScaAG1 and EScaAG2, duplicate AG homologs in the basal eudicot Eschscholzia californica show a high degree of similarity in sequence and expression, although EScaAG2 expression is lower than EScaAG1 expression. Functional studies employing virus-induced gene silencing (VIGS) demonstrate that knock down of EScaAG1 and 2 function leads to homeotic conversion of stamens into petaloid structures and defects in floral meristem termination. However, carpels are transformed into petaloid organs rather than sepaloid structures. We also show that a reduction of EScaAG1 and EScaAG2 expression leads to significantly increased expression of a subset of floral homeotic B genes. This work presents expression and functional analysis of the two basal eudicot AG homologs. The reduction of EScaAG1 and 2 functions results in the change of stamen to petal identity and a transformation of the central whorl organ identity from carpel into petal identity. Petal identity requires the presence of the floral homeotic B function and our results show that the expression of a subset of B function genes extends into the central whorl when the C function is reduced. We propose a model for the evolution of B function regulation by C function suggesting that the mode of B function gene regulation found in Eschscholzia is ancestral and the C-independent regulation as found in Arabidopsis is evolutionarily derived.

  19. Differentiation phenotypes of pancreatic islet beta- and alpha-cells are closely related with homeotic genes and a group of differentially expressed genes.

    PubMed

    Mizusawa, Noriko; Hasegawa, Tomoko; Ohigashi, Izumi; Tanaka-Kosugi, Chisato; Harada, Nagakatsu; Itakura, Mitsuo; Yoshimoto, Katsuhiko

    2004-04-28

    To identify the genes that determine differentiation phenotypes, we compared gene expression of pancreatic islet beta- and alpha-cells, which are derived from the common precursor and secrete insulin and glucagon, respectively. The expression levels of homeotic genes including Hox genes known to determine region specificity in the antero-posterior (AP) body axis, tissue-specific homeobox genes, and other 8,734 genes were compared in a beta- and alpha-cell line of MIN6 and alpha TC1.6. The expression of homeotic genes were surveyed with reverse transcription-polymerase chain reaction (RT-PCR) using degenerate primers corresponding to invariant amino acid sequences within the homeodomain and subsequently with specific primers. Expression of Hoxc6, Hoxc9, Hoxc10, Pdx1, Cdx2, Gbx2, Pax4, and Hlxb9 genes in MIN6 was higher than those in alpha TC1.6, while expression of Hoxa2, Hoxa3, Hoxa5, Hoxa6, Hoxa7, Hoxa9, Hoxa10, Hoxa13, Hoxb3, Hoxb5, Hoxb6, Hoxb13, Hoxb8, and Brain4 genes in alpha TC1.6 was higher than those in MIN6. Out of 8,734 mouse genes screened with high-density mouse cDNA microarrays for MIN6- and alpha TC1.6-derived cDNA, 58 and 25 genes were differentially over- and under-expressed in MIN6, respectively. GLUTag, which is derived from a large bowel tumor and expresses the proglucagon gene, showed a comparatively similar expression profile to that of alpha TC1.6 in both homeotic and other genes analyzed in cDNA microarray. Our results are consistent with the interpretation that not only the tissue-specific homeotic genes, but also Hox genes are related to differentiation phenotypes of pancreatic beta- and alpha-cells rather than their regional specification of the body in vertebrates.

  20. [Study of the olfactory response in the Drosophila homeotic mutant leg-aristae-wing complex gene].

    PubMed

    Simonova, O B; Sukhoverkhova, T I; Zhuravel', D A; Romanova, L G; Korochkin, L I

    2000-11-01

    Antennae are known to be olfactory organs in Drosophila. The leg-aristae-wing complex (lawc) mutation causes a homeotic transformation of the arista (the fifth element of antenna) into tarsal elements. To test how the homeotic transformation of the arista into the tarsus can affect behavior, we studied the olfactory response in the lawc mutants. The data were carefully processed by statistical methods. In spite of a low penetrance of the trait of arista transformation, the mutant flies were found to be approximately half as perceptible to attractant odors than the wild-type flies.

  1. Unique morphological changes in plant pathogenic phytoplasma-infected petunia flowers are related to transcriptional regulation of floral homeotic genes in an organ-specific manner.

    PubMed

    Himeno, Misako; Neriya, Yutaro; Minato, Nami; Miura, Chihiro; Sugawara, Kyoko; Ishii, Yoshiko; Yamaji, Yasuyuki; Kakizawa, Shigeyuki; Oshima, Kenro; Namba, Shigetou

    2011-09-01

    Abnormal flowers are often induced by infection of certain plant pathogens, e.g. phytoplasma, but the molecular mechanisms underlying these malformations have remained poorly understood. Here, we show that infection with OY-W phytoplasma (Candidatus Phytoplasma asteris, onion yellows phytoplasma strain, line OY-W) affects the expression of the floral homeotic genes of petunia plants in an organ-specific manner. Upon infection with OY-W phytoplasma, floral morphological changes, including conversion to leaf-like structures, were observed in sepals, petals and pistils, but not in stamens. As the expression levels of homeotic genes differ greatly between floral organs, we examined the expression levels of homeotic genes in each floral organ infected by OY-W phytoplasma, compared with healthy plants. The expression levels of several homeotic genes required for organ development, such as PFG, PhGLO1 and FBP7, were significantly downregulated by the phytoplasma infection in floral organs, except the stamens, suggesting that the unique morphological changes caused by the phytoplasma infection might result from the significant decrease in expression of some crucial homeotic genes. Moreover, the expression levels of TER, ALF and DOT genes, which are known to participate in floral meristem identity, were significantly downregulated in the phytoplasma-infected petunia meristems, implying that phytoplasma would affect an upstream signaling pathway of floral meristem identity. Our results suggest that phytoplasma infection may have complex effects on floral development, resulting in the unique phenotypes that were clearly distinct from the mutant flower phenotypes produced by the knock-out or the overexpression of certain homeotic genes. © 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.

  2. Homeotic Gene teashirt (tsh) has a neuroprotective function in amyloid-beta 42 mediated neurodegeneration.

    PubMed

    Moran, Michael T; Tare, Meghana; Kango-Singh, Madhuri; Singh, Amit

    2013-01-01

    Alzheimer's disease (AD) is a debilitating age related progressive neurodegenerative disorder characterized by the loss of cognition, and eventual death of the affected individual. One of the major causes of AD is the accumulation of Amyloid-beta 42 (Aβ42) polypeptides formed by the improper cleavage of amyloid precursor protein (APP) in the brain. These plaques disrupt normal cellular processes through oxidative stress and aberrant signaling resulting in the loss of synaptic activity and death of the neurons. However, the detailed genetic mechanism(s) responsible for this neurodegeneration still remain elusive. We have generated a transgenic Drosophila eye model where high levels of human Aβ42 is misexpressed in the differentiating photoreceptor neurons of the developing eye, which phenocopy Alzheimer's like neuropathology in the neural retina. We have utilized this model for a gain of function screen using members of various signaling pathways involved in the development of the fly eye to identify downstream targets or modifiers of Aβ42 mediated neurodegeneration. We have identified the homeotic gene teashirt (tsh) as a suppressor of the Aβ42 mediated neurodegenerative phenotype. Targeted misexpression of tsh with Aβ42 in the differentiating retina can significantly rescue neurodegeneration by blocking cell death. We found that Tsh protein is absent/ downregulated in the neural retina at this stage. The structure function analysis revealed that the PLDLS domain of Tsh acts as an inhibitor of the neuroprotective function of tsh in the Drosophila eye model. Lastly, we found that the tsh paralog, tiptop (tio) can also rescue Aβ42 mediated neurodegeneration. We have identified tsh and tio as new genetic modifiers of Aβ42 mediated neurodegeneration. Our studies demonstrate a novel neuroprotective function of tsh and its paralog tio in Aβ42 mediated neurodegeneration. The neuroprotective function of tsh is independent of its role in retinal determination.

  3. The putative SWI/SNF complex subunit BRAHMA activates flower homeotic genes in Arabidopsis thaliana.

    PubMed

    Hurtado, Lidia; Farrona, Sara; Reyes, Jose C

    2006-09-01

    Arabidopsis thaliana BRAHMA (BRM, also called AtBRM) is a SNF2 family protein homolog of Brahma, the ATPase of the Drosophila SWI/SNF complex involved in chromatin remodeling during transcription. Here we show that, in contrast to its Drosophila counterpart, BRM is not an essential gene. Thus, homozygous BRM loss of function mutants are viable but exhibit numerous defects including dwarfism, altered leaf and root development and several reproduction defects. The analysis of the progeny of self-fertilized heterozygous brm plants and reciprocal crosses between heterozygous and wild type plants indicated that disruption of BRM reduced both male and female gametophyte transmission. This was consistent with the presence of aborted ovules in the self-fertilized heterozygous flowers that contained arrested embryos predominantly at the two terminal cells stage. Furthermore, brm homozygous mutants were completely sterile. Flowers of brm loss-of-function mutants have several developmental abnormalities, including homeotic transformations in the second and third floral whorls. In accordance with these results, brm mutants present reduced levels of APETALA2, APETALA3, PISTILLATA and NAC-LIKE, ACTIVATED BY AP3/PI. We have previously shown that BRM strongly interacts with AtSWI3C. Now we extend our interaction studies demonstrating that BRM interacts weakly with AtSWI3B but not with AtSWI3A or AtSWI3D. In agreement with these results, the phenotype described in this study for brm plants is very similar to that previously described for the AtSWI3C mutant plants, suggesting that both proteins participate in the same genetic pathway or form a molecular complex.

  4. Ectopic expression of the HAM59 gene causes homeotic transformations of reproductive organs in sunflower (Helianthus annuus L.).

    PubMed

    Shulga, O A; Neskorodov, Ya B; Shchennikova, A V; Gaponenko, A K; Skryabin, K G

    2015-01-01

    The function of the HAM59 MADS-box gene in sunflower (Helianthus annuus L.) was studied to clarify homeotic C activity in the Asteraceae plant family. For the first time, transgenic sunflower plants with a modified pattern of HAM59 expression were obtained. It was shown that the HAM59 MADS-box transcription factor did mediate C activity in sunflower. In particular, it participated in termination of the floral meristem, repression of the cadastral function of A-activity, and together with other C-type sunflower protein HAM45-in the specification of the identity of stamens and pistils.

  5. Mutations in paralogous Hox genes result in overlapping homeotic transformations of the axial skeleton: evidence for unique and redundant function.

    PubMed

    Horan, G S; Kovàcs, E N; Behringer, R R; Featherstone, M S

    1995-05-01

    Hoxd-4 (previously known as Hox-4.2 and -5.1) is a mouse homeobox-containing gene homologous to the Drosophila homeotic gene Deformed. During embryogenesis, Hoxd-4 is expressed in the presumptive hindbrain and spinal cord, prevertebrae, and other tissues. In the adult, Hoxd-4 transcripts are expressed predominantly in the testis and kidney, and to a lesser extent in intestine and heart. To understand the role of Hoxd-4 during mouse embryogenesis, we generated Hoxd-4 mutant mice. Mice heterozygous or homozygous for the Hoxd-4 mutation exhibit homeotic transformations of the second cervical vertebrae (C2) to the first cervical vertebrae (C1) and malformations of the neural arches of C1 to C3 and of the basioccipital bone. The phenotype was incompletely penetrant and showed variable expressivity on both an F2 hybrid and 129 inbred genetic background. The mutant phenotype was detected in the cartilaginous skeleton of 14.5-day (E14.5) mutant embryos but no apparent differences were detected in the somites of E9.5 mutant embryos, suggesting that the abnormalities develop after E9.5 perhaps during or after resegmentation of the somites to form the prevertebrae. These results suggest that Hoxd-4 plays a role in conferring position information along the anteroposterior axis in the skeleton. The phenotypic similarities and differences between Hoxd-4 and previously reported Hoxa-4 and Hoxb-4 mutant mice suggest that Hox gene paralogs have both redundant and unique functions.

  6. Temporal and spatial expression of homeotic genes is important for segment-specific neuroblast 6-4 lineage formation in Drosophila.

    PubMed

    Kang, Sun-Young; Kim, Su-Na; Kim, Sang Hee; Jeon, Sang-Hak

    2006-06-30

    Different proliferation of neuroblast 6-4 (NB6-4) in the thorax and abdomen produces segmental specific expression pattern of several neuroblast marker genes. NB6-4 is divided to form four medialmost cell body glia (MM-CBG) per segment in thorax and two MM-CBG per segment in abdomen. As homeotic genes determine the identities of embryonic segments along theA/P axis, we investigated if temporal and specific expression of homeotic genes affects MM-CBG patterns in thorax and abdomen. A Ubx loss-of-function mutation was found to hardly affect MM-CBG formation, whereas abd-A and Abd-B caused the transformation of abdominal MM-CBG to their thoracic counterparts. On the other hand, gain-of-function mutants of Ubx, abd-A and Abd-B genes reduced the number of thoracic MM-CBG, indicating that thoracic MM-CBG resembled abdominal MM-CBG. However, mutations in Polycomb group (PcG) genes, which are negative transregulators of homeotic genes, did not cause the thoracic to abdominal MM-CBG pattern transformation although the number of MM-CBG in a few per-cent of embryos were partially reduced or abnormally patterned. Our results indicate that temporal and spa-tial expression of the homeotic genes is important to determine segmental-specificity of NB6-4 daughter cells along the anterior-posterior (A/P) axis.

  7. Floral homeotic C function genes repress specific B function genes in the carpel whorl of the basal eudicot California poppy (Eschscholzia californica)

    PubMed Central

    2010-01-01

    Background The floral homeotic C function gene AGAMOUS (AG) confers stamen and carpel identity and is involved in the regulation of floral meristem termination in Arabidopsis. Arabidopsis ag mutants show complete homeotic conversions of stamens into petals and carpels into sepals as well as indeterminacy of the floral meristem. Gene function analysis in model core eudicots and the monocots rice and maize suggest a conserved function for AG homologs in angiosperms. At the same time gene phylogenies reveal a complex history of gene duplications and repeated subfunctionalization of paralogs. Results EScaAG1 and EScaAG2, duplicate AG homologs in the basal eudicot Eschscholzia californica show a high degree of similarity in sequence and expression, although EScaAG2 expression is lower than EScaAG1 expression. Functional studies employing virus-induced gene silencing (VIGS) demonstrate that knock down of EScaAG1 and 2 function leads to homeotic conversion of stamens into petaloid structures and defects in floral meristem termination. However, carpels are transformed into petaloid organs rather than sepaloid structures. We also show that a reduction of EScaAG1 and EScaAG2 expression leads to significantly increased expression of a subset of floral homeotic B genes. Conclusions This work presents expression and functional analysis of the two basal eudicot AG homologs. The reduction of EScaAG1 and 2 functions results in the change of stamen to petal identity and a transformation of the central whorl organ identity from carpel into petal identity. Petal identity requires the presence of the floral homeotic B function and our results show that the expression of a subset of B function genes extends into the central whorl when the C function is reduced. We propose a model for the evolution of B function regulation by C function suggesting that the mode of B function gene regulation found in Eschscholzia is ancestral and the C-independent regulation as found in Arabidopsis is

  8. Hidden variability of floral homeotic B genes in Solanaceae provides a molecular basis for the evolution of novel functions.

    PubMed

    Geuten, Koen; Irish, Vivian

    2010-08-01

    B-class MADS box genes specify petal and stamen identities in several core eudicot species. Members of the Solanaceae possess duplicate copies of these genes, allowing for diversification of function. To examine the changing roles of such duplicate orthologs, we assessed the functions of B-class genes in Nicotiana benthamiana and tomato (Solanum lycopersicum) using virus-induced gene silencing and RNA interference approaches. Loss of function of individual duplicates can have distinct phenotypes, yet complete loss of B-class gene function results in extreme homeotic transformations of petal and stamen identities. We also show that these duplicate gene products have qualitatively different protein-protein interaction capabilities and different regulatory roles. Thus, compensatory changes in B-class MADS box gene duplicate function have occurred in the Solanaceae, in that individual gene roles are distinct, but their combined functions are equivalent. Furthermore, we show that species-specific differences in the stamen regulatory network are associated with differences in the expression of the microRNA miR169. Whereas there is considerable plasticity in individual B-class MADS box transcription factor function, there is overall conservation in the roles of the multimeric MADS box B-class protein complexes, providing robustness in the specification of petal and stamen identities. Such hidden variability in gene function as we observe for individual B-class genes can provide a molecular basis for the evolution of regulatory functions that result in novel morphologies.

  9. Rice open beak is a negative regulator of class 1 knox genes and a positive regulator of class B floral homeotic gene.

    PubMed

    Horigome, Ayako; Nagasawa, Nobuhiro; Ikeda, Kyoko; Ito, Momoyo; Itoh, Jun-Ichi; Nagato, Yasuo

    2009-06-01

    Numerous genes are involved in the regulation of plant development, including those that regulate floral homeotic genes, We identified two recessive allelic rice mutants, open beak-1 (opb-1) and opb-2, which exhibited pleiotropic defects in leaf morphogenesis, inflorescence architecture, and floral organ identity. Abnormal cell proliferation was observed in the leaves and spikelets, and ectopic or overexpression of several class 1 knox genes was detected; thus, the abnormal cell proliferation in opb mutants is probably caused by ectopic class 1 knox gene expression. The opb mutants also had defects in floral organ identity, resulting in the development of mosaic organs, including gluminous lodicules, staminoid lodicules, and pistiloid stamens. These results, together with the reduced expression of a class B gene, indicate that OPB positively regulates the expression of class B genes. Map-based cloning revealed that OPB encodes a transcription factor that is orthologous to the Arabidopsis JAGGED gene and is expressed in leaf primordia, inflorescence meristem, rachis branch meristems, floral meristem, and floral organ primordia. Taken together, our data suggest that the OPB gene affects cellular proliferation and floral organ identity through the regulation of class 1 knox genes and floral homeotic genes.

  10. The Histone Methyltransferase Gene Absent, Small, or Homeotic Discs-1 Like Is Required for Normal Hox Gene Expression and Fertility in Mice.

    PubMed

    Brinkmeier, Michelle L; Geister, Krista A; Jones, Morgan; Waqas, Meriam; Maillard, Ivan; Camper, Sally A

    2015-11-01

    Chromatin remodeling influences gene expression in developing and adult organisms. Active and repressive marks of histone methylation dictate the embryonic expression boundaries of developmentally regulated genes, including the Hox gene cluster. Drosophila ash1 (absent, small or homeotic discs 1) gene encodes a histone methyltransferase essential for regulation of Hox gene expression that interacts genetically with other members of the trithorax group (TrxG). While mammalian members of the mixed lineage leukemia (Mll) family of TrxG genes have roles in regulation of Hox gene expression, little is known about the expression and function of the mammalian ortholog of the Drosophila ash1 gene, Ash1-like (Ash1l). Here we report the expression of mouse Ash1l gene in specific structures within various organs and provide evidence that reduced Ash1l expression has tissue-specific effects on mammalian development and adult homeostasis. Mutants exhibit partially penetrant postnatal lethality and failure to thrive. Surviving mutants have growth insufficiency, skeletal transformations, and infertility associated with developmental defects in both male and female reproductive organs. Specifically, expression of Hoxa11 and Hoxd10 are altered in the epididymis of Ash1l mutant males and Hoxa10 is reduced in the uterus of Ash1l mutant females. In summary, we show that the histone methyltransferase Ash1l is important for the development and function of several tissues and for proper expression of homeotic genes in mammals. © 2015 by the Society for the Study of Reproduction, Inc.

  11. The Histone Methyltransferase Gene Absent, Small, or Homeotic Discs-1 Like Is Required for Normal Hox Gene Expression and Fertility in Mice1

    PubMed Central

    Brinkmeier, Michelle L.; Geister, Krista A.; Jones, Morgan; Waqas, Meriam; Maillard, Ivan; Camper, Sally A.

    2015-01-01

    Chromatin remodeling influences gene expression in developing and adult organisms. Active and repressive marks of histone methylation dictate the embryonic expression boundaries of developmentally regulated genes, including the Hox gene cluster. Drosophila ash1 (absent, small or homeotic discs 1) gene encodes a histone methyltransferase essential for regulation of Hox gene expression that interacts genetically with other members of the trithorax group (TrxG). While mammalian members of the mixed lineage leukemia (Mll) family of TrxG genes have roles in regulation of Hox gene expression, little is known about the expression and function of the mammalian ortholog of the Drosophila ash1 gene, Ash1-like (Ash1l). Here we report the expression of mouse Ash1l gene in specific structures within various organs and provide evidence that reduced Ash1l expression has tissue-specific effects on mammalian development and adult homeostasis. Mutants exhibit partially penetrant postnatal lethality and failure to thrive. Surviving mutants have growth insufficiency, skeletal transformations, and infertility associated with developmental defects in both male and female reproductive organs. Specifically, expression of Hoxa11 and Hoxd10 are altered in the epididymis of Ash1l mutant males and Hoxa10 is reduced in the uterus of Ash1l mutant females. In summary, we show that the histone methyltransferase Ash1l is important for the development and function of several tissues and for proper expression of homeotic genes in mammals. PMID:26333994

  12. Murine genes related to the Drosophila AbdB homeotic genes are sequentially expressed during development of the posterior part of the body.

    PubMed Central

    Izpisúa-Belmonte, J C; Falkenstein, H; Dollé, P; Renucci, A; Duboule, D

    1991-01-01

    The cloning, characterization and developmental expression patterns of two novel murine Hox genes, Hox-4.6 and Hox-4.7, are reported. Structural data allow us to classify the four Hox-4 genes located in the most upstream (5') position in the HOX-4 complex as members of a large family of homeogenes related to the Drosophila homeotic gene Abdominal B (AbdB). It therefore appears that these vertebrate genes are derived from a selective amplification of an ancestral gene which gave rise, during evolution, to the most posterior of the insect homeotic genes so far described. In agreement with the structural colinearity, these genes have very posteriorly restricted expression profiles. In addition, their developmental expression is temporally regulated according to a cranio-caudal sequence which parallels the physical ordering of these genes along the chromosome. We discuss the phylogenetic alternative in the evolution of genetic complexity by amplifying either genes or regulatory sequences, as exemplified by this system in the mouse and Drosophila. Furthermore, the possible role of 'temporal colinearity' in the ontogeny of all coelomic (metamerized) metazoans showing a temporal anteroposterior morphogenetic progression is addressed. Images PMID:1676674

  13. BASIC PENTACYSTEINE1, a GA Binding Protein That Induces Conformational Changes in the Regulatory Region of the Homeotic Arabidopsis Gene SEEDSTICK

    PubMed Central

    Kooiker, Maarten; Airoldi, Chiara A.; Losa, Alessia; Manzotti, Priscilla S.; Finzi, Laura; Kater, Martin M.; Colombo, Lucia

    2005-01-01

    The mechanisms for the regulation of homeotic genes are poorly understood in most organisms, including plants. We identified BASIC PENTACYSTEINE1 (BPC1) as a regulator of the homeotic Arabidopsis thaliana gene SEEDSTICK (STK), which controls ovule identity, and characterized its mechanism of action. A combination of tethered particle motion analysis and electromobility shift assays revealed that BPC1 is able to induce conformational changes by cooperative binding to purine-rich elements present in the STK regulatory sequence. Analysis of STK expression in the bpc1 mutant showed that STK is upregulated. Our results give insight into the regulation of gene expression in plants and provide the basis for further studies to understand the mechanisms that control ovule identity in Arabidopsis. PMID:15722463

  14. Isolation and functional analyses of a putative floral homeotic C-function gene in a basal eudicot London plane tree (Platanus acerifolia).

    PubMed

    Zhang, Jiaqi; Li, Zhineng; Guo, Cong; Liu, Guofeng; Bao, Manzhu

    2013-01-01

    The identification of mutants in model plant species has led to the isolation of the floral homeotic function genes that play crucial roles in flower organ specification. However, floral homeotic C-function genes are rarely studied in basal eudicots. Here, we report the isolation and characterization of the AGAMOUS (AG) orthologous gene (PaAG) from a basal eudicot London plane tree (Platanus acerifolia Willd). Phylogenetic analysis showed that PaAG belongs to the C- clade AG group of genes. PaAG was found to be expressed predominantly in the later developmental stages of male and female inflorescences. Ectopic expression of PaAG-1 in tobacco (Nicotiana tabacum) resulted in morphological alterations of the outer two flower whorls, as well as some defects in vegetative growth. Scanning electron micrographs (SEMs) confirmed homeotic sepal-to-carpel transformation in the transgenic plants. Protein interaction assays in yeast cells indicated that PaAG could interact directly with PaAP3 (a B-class MADS-box protein in P. acerifolia), and also PaSEP1 and PaSEP3 (E-class MADS-box proteins in P. acerifolia). This study performed the functional analysis of AG orthologous genes outside core eudicots and monocots. Our findings demonstrate a conserved functional role of AG homolog in London plane tree, which also represent a contribution towards understanding the molecular mechanisms of flower development in this monoecious tree species.

  15. Isolation and Functional Analyses of a Putative Floral Homeotic C-Function Gene in a Basal Eudicot London Plane Tree (Platanus acerifolia)

    PubMed Central

    Liu, Guofeng; Bao, Manzhu

    2013-01-01

    The identification of mutants in model plant species has led to the isolation of the floral homeotic function genes that play crucial roles in flower organ specification. However, floral homeotic C-function genes are rarely studied in basal eudicots. Here, we report the isolation and characterization of the AGAMOUS (AG) orthologous gene (PaAG) from a basal eudicot London plane tree (Platanus acerifolia Willd). Phylogenetic analysis showed that PaAG belongs to the C- clade AG group of genes. PaAG was found to be expressed predominantly in the later developmental stages of male and female inflorescences. Ectopic expression of PaAG-1 in tobacco (Nicotiana tabacum) resulted in morphological alterations of the outer two flower whorls, as well as some defects in vegetative growth. Scanning electron micrographs (SEMs) confirmed homeotic sepal-to-carpel transformation in the transgenic plants. Protein interaction assays in yeast cells indicated that PaAG could interact directly with PaAP3 (a B-class MADS-box protein in P. acerifolia), and also PaSEP1 and PaSEP3 (E-class MADS-box proteins in P. acerifolia). This study performed the functional analysis of AG orthologous genes outside core eudicots and monocots. Our findings demonstrate a conserved functional role of AG homolog in London plane tree, which also represent a contribution towards understanding the molecular mechanisms of flower development in this monoecious tree species. PMID:23691041

  16. Characterization of candidate class A, B and E floral homeotic genes from the perianthless basal angiosperm Chloranthus spicatus (Chloranthaceae).

    PubMed

    Li, Gui-Sheng; Meng, Zheng; Kong, Hong-Zhi; Chen, Zhi-Duan; Theissen, Günter; Lu, An-Min

    2005-09-01

    The classic ABC model explains the activities of each class of floral homeotic genes in specifying the identity of floral organs. Thus, changes in these genes may underlay the origin of floral diversity during evolution. In this study, three MADS-box genes were isolated from the perianthless basal angiosperm Chloranthus spicatus. Sequence and phylogenetic analyses revealed that they are AP1-like, AP3-like and SEP3-like genes, and hence these genes were termed CsAP1, CsAP3 and CsSEP3, respectively. Due to these assignments, they represent candidate class A, class B and class E genes, respectively. Expression patterns suggest that the CsAP1, CsAP3 and CsSEP3 genes function during flower development of C. spicatus. CsAP1 is expressed broadly in the flower, which may reflect the ancestral function of SQUA-like genes in the specification of inflorescence and floral meristems rather than in patterning of the flower. CsAP3 is exclusively expressed in male floral organs, providing the evidence that AP3-like genes have ancestral function in differentiation between male and female reproductive organs. CsSEP3 expression is not detectable in spike meristems, but its mRNA accumulates throughout the flower, supporting the view that SEP-like genes have conserved expression pattern and function throughout angiosperm. Studies of synonymous vs nonsynonymous nucleotide substitutions indicate that these genes have not evolved under changes in evolutionary forces. All the data above suggest that the genes may have maintained at least some ancestral functions despite the lack of perianth in the flowers of C. spicatus.

  17. A double-bromodomain protein, FSH-S, activates the homeotic gene ultrabithorax through a critical promoter-proximal region.

    PubMed

    Chang, Yuh-Long; King, Balas; Lin, Shu-Chun; Kennison, James A; Huang, Der-Hwa

    2007-08-01

    More than a dozen trithorax group (trxG) proteins are involved in activation of Drosophila HOX genes. How they act coordinately to integrate signals from distantly located enhancers is not fully understood. The female sterile (1) homeotic (fs(1)h) gene is one of the trxG genes that is most critical for Ultrabithorax (Ubx) activation. We show that one of the two double-bromodomain proteins encoded by fs(1)h acts as an essential factor in the Ubx proximal promoter. First, overexpression of the small isoform FSH-S, but not the larger one, can induce ectopic expression of HOX genes and cause body malformation. Second, FSH-S can stimulate Ubx promoter in cultured cells through a critical proximal region in a bromodomain-dependent manner. Third, purified FSH-S can bind specifically to a motif within this region that was previously known as the ZESTE site. The physiological relevance of FSH-S is ascertained using transgenic embryos containing a modified Ubx proximal promoter and chromatin immunoprecipitation. In addition, we show that FSH-S is involved in phosphorylation of itself and other regulatory factors. We suggest that FSH-S acts as a critical component of a regulatory circuitry mediating long-range effects of distant enhancers.

  18. Homeotic selector genes control the patterning of seven-up expressing cells in the Drosophila dorsal vessel.

    PubMed

    Ryan, Kathryn M; Hoshizaki, Deborah K; Cripps, Richard M

    2005-09-01

    The linear cardiac tube of Drosophila, the dorsal vessel, is an important model organ for the study of cardiac specification and patterning in vertebrates. In Drosophila, the Hox segmentation gene abdominal-A (abd-A) is required for the specification of a functionally distinct heart region at the posterior of the dorsal vessel, from which blood is pumped anteriorly through a tube termed the aorta. Since we have previously shown that the posterior part of the aorta is specified during embryogenesis to form the adult heart during metamorphosis, we determined if the embryonic aorta is also patterned by the function of Hox segmentation genes. Using gain- and loss-of-function experiments, we demonstrate that the three Hox genes expressed in the posterior aorta and heart are sufficient to confer heart or posterior aorta fate throughout the dorsal vessel. Additionally, we demonstrate that Ultrabithorax and abd-A, but not Antennapedia, function to control cell number in the dorsal vessel. These studies add robustness to the model that homeotic selector genes pattern the Drosophila dorsal vessel, and further extend our understanding of how the cardiac tube is patterned in animal models.

  19. Spatial and temporal expression of the orchid floral homeotic gene DOMADS1 is mediated by its upstream regulatory regions.

    PubMed

    Yu, Hao; Yang, Shu Hua; Goh, Chong Jin

    2002-05-01

    The orchid floral homeotic gene, DOMADSI, is a marker gene specifically expressed in the transitional shoot apical meristem during floral transition in Dendrobium Madame Thong-In. DOMADSI is not detectable in vegetative tissues except a weak expression in the stem. Its transcript is uniformly localized in both of the inflorescence meristem and floral primordia, and later expressed in almost all of the floral organs. We isolated and sequenced a 3.5 kb DOMADSI promoter fragment upstream of the transcription start site, demonstrating the location of several putative DNA-binding sites, through which MADS-box and class I knox genes may modulate the DOMADSI expression. To gain insight into the molecular basis of the regulation of DOMADS1, deletion analysis of the DOMADSI::beta-glucuronidase (GUS) gene fusions was performed by means of the stable orchid transformation systems. The study shows that the full-length upstream promoter sequence confers the same spatial and temporal GUS staining pattern as that of the distribution of DOMADSI RNA during orchid development. We also identified the distinct cis-acting regulatory regions required for the control of DOMADS1 expression in vegetative and reproductive tissues, as well as the shoot apical meristem during floral transition.

  20. Structure of transcripts from the homeotic Antennapedia gene of Drosophila melanogaster: two promoters control the major protein-coding region.

    PubMed Central

    Laughon, A; Boulet, A M; Bermingham, J R; Laymon, R A; Scott, M P

    1986-01-01

    The Antennapedia (Antp) homeotic gene of Drosophila melanogaster regulates segmental identity in the thorax. Loss of Antp function results in altered development of the embryonic thoracic segments or can cause legs to be transformed into antennae. Certain combinations of Antp recessive lethal alleles complement to permit normal development. The structure of the Antp gene, analyzed by sequencing cDNA clones and exons and by transcript mapping, revealed some of the basis for its genetic complexity. It has two promoters governing two nested transcription units, one unit 36 and one 103 kilobase pairs (kb) long. Both units incorporated the same protein-coding exons, all of which are located in the 3'-most 13 kb of the gene. The two promoters resulted in the attachment of either of two long noncoding leader sequences (1.5 and 1.7 kb) to a 1.1-kb open reading frame. Both transcription units used the same pair of alternative polyadenylation sites 1.4 kb apart; the choice of sites was developmentally regulated. Some of the mutations that disrupt the larger transcription unit complemented a mutation affecting the smaller one. Dominant mutations that transform antennae into legs split the gene but left the coding exons intact. The encoded protein has unusually long runs of glutamine and a homeodomain near the C terminus. Images PMID:2879223

  1. Characterization of the Antirrhinum floral homeotic MADS-box gene deficiens: evidence for DNA binding and autoregulation of its persistent expression throughout flower development.

    PubMed Central

    Schwarz-Sommer, Z; Hue, I; Huijser, P; Flor, P J; Hansen, R; Tetens, F; Lönnig, W E; Saedler, H; Sommer, H

    1992-01-01

    We have determined the structure of the floral homeotic deficiens (defA) gene whose mutants display sepaloid petals and carpelloid stamens, and have analysed its spatial and temporal expression pattern. In addition, several mutant alleles (morphoalleles) were studied. The results of these analyses define three functional domains of the DEF A protein and identify in the deficiens promoter a possible cis-acting binding site for a transcription factor which specifically upregulates expression of deficiens in petals and stamens. In vitro DNA binding studies show that DEF A binds to specific DNA motifs as a heterodimer, together with the protein product of the floral homeotic globosa gene, thus demonstrating that the protein encoded by deficiens is a DNA binding protein. Furthermore, Northern analysis of a temperature sensitive allele at permissive and non-permissive temperatures provides evidence for autoregulation of the persistent expression of deficiens throughout flower development. A possible mechanism of autoregulation is discussed. Images PMID:1346760

  2. Detection of a true breeding homeotic gene mutant Pps-1 with partially petaloid sepals in opium poppy (Papaver somniferum L.) and its genetic behavior.

    PubMed

    Dhawan, Om Prakash; Dubey, Mukesh Kumar; Khanuja, Suman Preet Singh

    2007-01-01

    A spontaneous true breeding homeotic gene mutant Pps-1 with distinct partial petaloid sepals was detected in the population of downy mildew (DM)-resistant elite accession I-14 during our studies for the identification of disease resistance sources in opium poppy. The trait was found to be stable and inherited truly in the subsequent generations. Genetic studies were carried out through systematic reciprocal crosses with the parental wild-type genotype I-14, and segregation pattern of phenotypic characteristics in F(1) and F(2) populations clearly indicated single recessive nuclear gene control of the mutant character. The studies have demonstrated that the mutant phenotype is due to mutations at the Pps-1 locus that possibly corresponds to B-class function (according to ABC model) with negative control function. The mutant Pps-1 being single-whorl homeotic mutant might greatly help in providing insight into mechanisms of flower development in opium poppy.

  3. Heterotopic expression of class B floral homeotic genes supports a modified ABC model for tulip (Tulipa gesneriana).

    PubMed

    Kanno, Akira; Saeki, Hiroshi; Kameya, Toshiaki; Saedler, Heinz; Theissen, Günter

    2003-07-01

    In higher eudicotyledonous angiosperms the floral organs are typically arranged in four different whorls, containing sepals, petals, stamens and carpels. According to the ABC model, the identity of these organs is specified by floral homeotic genes of class A, A+B, B+C and C, respectively. In contrast to the sepal and petal whorls of eudicots, the perianths of many plants from the Liliaceae family have two outer whorls of almost identical petaloid organs, called tepals. To explain the Liliaceae flower morphology, van Tunen et al. (1993) proposed a modified ABC model, exemplified with tulip. According to this model, class B genes are not only expressed in whorls 2 and 3, but also in whorl 1. Thus the organs of both whorls 1 and 2 express class A plus class B genes and, therefore, get the same petaloid identity. To test this modified ABC model we have cloned and characterized putative class B genes from tulip. Two DEF- and one GLO-like gene were identified, named TGDEFA, TGDEFB and TGGLO. Northern hybridization analysis showed that all of these genes are expressed in whorls 1, 2 and 3 (outer and inner tepals and stamens), thus corroborating the modified ABC model. In addition, these experiments demonstrated that TGGLO is also weakly expressed in carpels, leaves, stems and bracts. Gel retardation assays revealed that TGGLO alone binds to DNA as a homodimer. In contrast, TGDEFA and TGDEFB cannot homodimerize, but make heterodimers with PI. Homodimerization of GLO-like protein has also been reported for lily, suggesting that this phenomenon is conserved within Liliaceae plants or even monocot species.

  4. Why are orchid flowers so diverse? Reduction of evolutionary constraints by paralogues of class B floral homeotic genes

    PubMed Central

    Mondragón-Palomino, Mariana; Theißen, Günter

    2009-01-01

    Background The nearly 30 000 species of orchids produce flowers of unprecedented diversity. However, whether specific genetic mechanisms contributed to this diversity is a neglected topic and remains speculative. We recently published a theory, the ‘orchid code’, maintaining that the identity of the different perianth organs is specified by the combinatorial interaction of four DEF-like MADS-box genes with other floral homeotic genes. Scope Here the developmental and evolutionary implications of our theory are explored. Specifically, it is shown that all frequent floral terata, including all peloric types, can be explained by monogenic gain- or-loss-of-function mutants, changing either expression of a DEF-like or CYC-like gene. Supposed dominance or recessiveness of mutant alleles is correlated with the frequency of terata in both cultivation and nature. Our findings suggest that changes in DEF- and CYC-like genes not only underlie terata but also the natural diversity of orchid species. We argue, however, that true changes in organ identity are rare events in the evolution of orchid flowers, even though we review some likely cases. Conclusions The four DEF paralogues shaped floral diversity in orchids in a dramatic way by modularizing the floral perianth based on a complex series of sub- and neo-functionalization events. These genes may have eliminated constraints, so that different kinds of perianth organs could then evolve individually and thus often in dramatically different ways in response to selection by pollinators or by genetic drift. We therefore argue that floral diversity in orchids may be the result of an unprecedented developmental genetic predisposition that originated early in orchid evolution. PMID:19141602

  5. Why are orchid flowers so diverse? Reduction of evolutionary constraints by paralogues of class B floral homeotic genes.

    PubMed

    Mondragón-Palomino, Mariana; Theissen, Günter

    2009-08-01

    The nearly 30 000 species of orchids produce flowers of unprecedented diversity. However, whether specific genetic mechanisms contributed to this diversity is a neglected topic and remains speculative. We recently published a theory, the 'orchid code', maintaining that the identity of the different perianth organs is specified by the combinatorial interaction of four DEF-like MADS-box genes with other floral homeotic genes. Here the developmental and evolutionary implications of our theory are explored. Specifically, it is shown that all frequent floral terata, including all peloric types, can be explained by monogenic gain- or-loss-of-function mutants, changing either expression of a DEF-like or CYC-like gene. Supposed dominance or recessiveness of mutant alleles is correlated with the frequency of terata in both cultivation and nature. Our findings suggest that changes in DEF- and CYC-like genes not only underlie terata but also the natural diversity of orchid species. We argue, however, that true changes in organ identity are rare events in the evolution of orchid flowers, even though we review some likely cases. The four DEF paralogues shaped floral diversity in orchids in a dramatic way by modularizing the floral perianth based on a complex series of sub- and neo-functionalization events. These genes may have eliminated constraints, so that different kinds of perianth organs could then evolve individually and thus often in dramatically different ways in response to selection by pollinators or by genetic drift. We therefore argue that floral diversity in orchids may be the result of an unprecedented developmental genetic predisposition that originated early in orchid evolution.

  6. Determination of flower structure in Elaeis guineensis: do palms use the same homeotic genes as other species?

    PubMed

    Adam, Helene; Jouannic, Stefan; Morcillo, Fabienne; Verdeil, Jean-Luc; Duval, Yves; Tregear, James W

    2007-07-01

    In this article a review is made of data recently obtained on the structural diversity and possible functions of MADS box genes in the determination of flower structure in the African oil palm (Elaeis guineensis). MADS box genes play a dominant role in the ABC model established to explain how floral organ identity is determined in model dicotyledon species such as Arabidopsis thaliana and Antirrhinum majus. In the monocotyledons, although there appears to be a broad general conservation of ABC gene functions, the model itself needs to be adapted in some cases, notably for certain species which produce flowers with sepals and petals of similar appearance. For the moment, ABC genes remain unstudied in a number of key monocot clades, so only a partial picture is available for the Liliopsida as a whole. The aim of this article is to summarize data recently obtained for the African oil palm Elaeis guineensis, a member of the family Arecaceae (Arecales), and to discuss their significance with respect to knowledge gained from other Angiosperm groups, particularly within the monocotyledons. The essential details of reproductive development in oil palm are discussed and an overview is provided of the structural and functional characterization of MADS box genes likely to play a homeotic role in flower development in this species. The structural and functional data provide evidence for a general conservation of the generic 'ABC' model in oil palm, rather than the 'modified ABC model' proposed for some other monocot species which produce homochlamydeous flowers (i.e. with morphologically similar organs in both perianth whorls), such as members of the Liliales. Our oil palm data therefore follow a similar pattern to those obtained for other Commelinid species in the orders Commelinales and Poales. The significance of these findings is discussed.

  7. Determination of Flower Structure in Elaeis guineensis: Do Palms use the Same Homeotic Genes as Other Species?

    PubMed Central

    Adam, Helene; Jouannic, Stefan; Morcillo, Fabienne; Verdeil, Jean-Luc; Duval, Yves; Tregear, James W.

    2007-01-01

    Aims In this article a review is made of data recently obtained on the structural diversity and possible functions of MADS box genes in the determination of flower structure in the African oil palm (Elaeis guineensis). MADS box genes play a dominant role in the ABC model established to explain how floral organ identity is determined in model dicotyledon species such as Arabidopsis thaliana and Antirrhinum majus. In the monocotyledons, although there appears to be a broad general conservation of ABC gene functions, the model itself needs to be adapted in some cases, notably for certain species which produce flowers with sepals and petals of similar appearance. For the moment, ABC genes remain unstudied in a number of key monocot clades, so only a partial picture is available for the Liliopsida as a whole. The aim of this article is to summarize data recently obtained for the African oil palm Elaeis guineensis, a member of the family Arecaceae (Arecales), and to discuss their significance with respect to knowledge gained from other Angiosperm groups, particularly within the monocotyledons. Scope The essential details of reproductive development in oil palm are discussed and an overview is provided of the structural and functional characterization of MADS box genes likely to play a homeotic role in flower development in this species. Conclusions The structural and functional data provide evidence for a general conservation of the generic ‘ABC’ model in oil palm, rather than the ‘modified ABC model’ proposed for some other monocot species which produce homochlamydeous flowers (i.e. with morphologically similar organs in both perianth whorls), such as members of the Liliales. Our oil palm data therefore follow a similar pattern to those obtained for other Commelinid species in the orders Commelinales and Poales. The significance of these findings is discussed. PMID:17355996

  8. Rice MADS6 interacts with the floral homeotic genes SUPERWOMAN1, MADS3, MADS58, MADS13, and DROOPING LEAF in specifying floral organ identities and meristem fate.

    PubMed

    Li, Haifeng; Liang, Wanqi; Hu, Yun; Zhu, Lu; Yin, Changsong; Xu, Jie; Dreni, Ludovico; Kater, Martin M; Zhang, Dabing

    2011-07-01

    AGAMOUS-LIKE6 (AGL6) genes play essential roles in flower development, but whether and how they work with floral organ identity genes remain less understood. Here, we describe interactions of the rice (Oryza sativa) AGL6 gene MADS6 with other rice floral homeotic genes in flower development. Genetic analyses revealed that MADS6 specifies the identity of the three inner whorls and floral meristem determinacy redundantly with SUPERWOMAN1/MADS16 (B-gene) or MADS3 (C-gene). MADS6 was shown to define carpel/ovule development and floral determinacy by interacting with MADS13 (D-gene) and control the palea and floral meristem identities together with the YABBY gene DROOPING LEAF. Expression analyses revealed that the transcript levels of six B-, C-, and E-class genes were reduced in mads6-1 at the early flower developmental stage, suggesting that MADS6 is a key regulator of early flower development. Moreover, MADS6 can directly bind to a putative regulatory motif on MADS58 (C-gene), and mads6-1 mads58 displayed phenotypes similar to that of mads6-1. These results suggest that MADS6 is a key player in specifying flower development via interacting with other floral homeotic genes in rice, thus providing new insights into the mechanism by which flower development is controlled.

  9. A DEF/GLO-like MADS-box gene from a gymnosperm: Pinus radiata contains an ortholog of angiosperm B class floral homeotic genes.

    PubMed

    Mouradov, A; Hamdorf, B; Teasdale, R D; Kim, J T; Winter, K U; Theissen, G

    1999-09-01

    The specification of floral organ identity during development depends on the function of a limited number of homeotic genes grouped into three classes: A, B, and C. Pairs of paralogous B class genes, such as DEF and GLO in Antirrhinum, and AP3 and PI in Arabidopsis, are required for establishing petal and stamen identity. To gain a better understanding of the evolutionary origin of petals and stamens, we have looked for orthologs of B class genes in conifers. Here we report cDNA cloning of PrDGL (Pinus radiata DEF/GLO-like gene) from radiata pine. We provide phylogenetic evidence that PrDGL is closely related to both DEF- and GLO-like genes of angiosperms, and is thus among the first putative orthologs of floral homeotic B function genes ever reported from a gymnosperm. Expression of PrDGL is restricted to the pollen strobili (male cones) and was not detected in female cones. PrDGL expression was first detected in emergent male cone primordia and persisted through the early stages of pollen cone bud differentiation. Based on the results of our phylogeny reconstructions and expression studies, we suggest that PrDGL could play a role in distinguishing between male (where expression is on) and female reproductive structures (where expression is off) in radiata pine. We speculate that this could be the general function of DEF/GLO-like genes in gymnosperms that may have been recruited for the distinction between stamens and carpels, the male and female reproductive organs of flowering plants, during the evolution of angiosperms out of gymnosperm-like ancestors. Copyright 1999 Wiley-Liss, Inc.

  10. Cell-type-specific mechanisms of transcriptional repression by the homeotic gene products UBX and ABD-A in Drosophila embryos.

    PubMed Central

    Appel, B; Sakonju, S

    1993-01-01

    The homeotic genes of Drosophila melanogaster, which are required for specification of segmental identities, encode proteins capable of regulating gene expression. We have chosen to study the organization and function of a regulatory target in an attempt to learn how homeotic gene products provide appropriate transcriptional controls. We identified 30 common binding sites for the proteins encoded by the Ultrabithorax (Ubx) and abdominal-A (abd-A) genes within a negatively regulated target, the P2 promoter of the Antennapedia (Antp) gene. By systematically mutagenizing binding sites and observing the resulting P2 expression pattern in embryos, we have found evidence for cell-type-specific interactions that are mediated by these sequences. In certain neuronal cells, UBX and ABD-A proteins appear to repress by competing for common binding sites with another homeodomain protein, which we propose to be ANTP acting to induce P2 transcription in an autoregulatory manner. In sets of cells that contribute to the tracheal system, UBX and ABD-A repress by counteracting the function of a factor acting at independent sites. The latter mechanism of repression requires only that multiple homeodomain binding sequences be present and is not dependent on any particular binding site. Images PMID:8096172

  11. Deficiens, a homeotic gene involved in the control of flower morphogenesis in Antirrhinum majus: the protein shows homology to transcription factors.

    PubMed Central

    Sommer, H; Beltrán, J P; Huijser, P; Pape, H; Lönnig, W E; Saedler, H; Schwarz-Sommer, Z

    1990-01-01

    Deficiens (defA+) is a homeotic gene involved in the genetic control of Antirrhinum majus flower development. Mutation of this gene (defA-1) causes homeotic transformation of petals into sepals and of stamina into carpels in flowers displaying the 'globifera' phenotype, as shown by cross sections and scanning electronmicroscopy of developing flowers. A cDNA derived from the wild type defA+ gene has been cloned by differential screening of a subtracted 'flower specific' cDNA library. The identity of this cDNA with the defA+ gene product has been confirmed by utilizing the somatic and germinal instability of defA-1 mutants. According to Northern blot analyses the defA+ gene is expressed in flowers but not in leaves, and its expression is nearly constant during all stages of flower development. The 1.1 kb long mRNA has a 681 bp long open reading frame that can code for a putative protein of 227 amino acids (mol. wt 26.2 kd). At its N-terminus the DEF A protein reveals homology to a conserved domain of the regulatory proteins SRF (activating c-fos) in mammals and GRM/PRTF (regulating mating type) in yeast. We discuss the structure and the possible function of the DEF A protein in the control of floral organogenesis. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. PMID:1968830

  12. Arabidopsis TERMINAL FLOWER 2 gene encodes a heterochromatin protein 1 homolog and represses both FLOWERING LOCUS T to regulate flowering time and several floral homeotic genes.

    PubMed

    Kotake, Toshihisa; Takada, Shinobu; Nakahigashi, Kenji; Ohto, Masaaki; Goto, Koji

    2003-06-01

    Floral transition should be strictly regulated because it is one of the most critical developmental processes in plants. Arabidopsis terminal flower 2 (tfl2) mutants show an early-flowering phenotype that is relatively insensitive to photoperiod, as well as several other pleiotropic phenotypes. We found that the early flowering of tfl2 is caused mainly by ectopic expression of the FLOWERING LOCUS T (FT) gene, a floral pathway integrator. Molecular cloning of TFL2 showed that it encodes a protein with homology to heterochromatin protein 1 (HP1) of animals and Swi6 of fission yeast. TFL2 protein localizes in subnuclear foci and expression of the TFL2 gene complemented yeast swi6(-) mutants. These results suggested that TFL2 might function as an HP1 in Arabidopsis: Gene expression analyses using DNA microarrays, however, did not show an increase in the expression of heterochromatin genes in tfl2 mutants but instead showed the upregulation of the floral homeotic genes APETALA3, PISTILLATA, AGAMOUS and SEPALLATA3. The pleiotropic phenotype of the tfl2 mutant could reflect the fact that TFL2 represses the expression of multiple genes. Our results demonstrate that despite its homology to HP1, TFL2 is involved in the repression of specific euchromatin genes and not heterochromatin genes in Arabidopsis.

  13. In vivo mutagenesis of the Hoxb8 hexapeptide domain leads to dominant homeotic transformations that mimic the loss-of-function mutations in genes of the Hoxb cluster.

    PubMed

    Medina-Martínez, Olga; Ramírez-Solis, Ramiro

    2003-12-01

    Hox proteins are transcription factors that control developmental pathways along the anteroposterior axis of vertebrates. On their own, Hox proteins bind DNA weakly, but they gain specificity and affinity by interaction with members of the PBC subfamily of homeobox proteins. In vitro studies indicate that most of these interactions are mediated by the conserved hexapeptide motif of the Hox proteins. To study the significance of these interactions in vivo, we have generated mice that carry mutations in the Hoxb8 hexapeptide motif. Analysis of skeletal features of these mice reveals the presence of a dominant phenotype consisting of homeotic transformations, similar to those observed in mice with a loss-of-function of Hox genes, such as Hoxa7, Hoxb7, and Hoxb9. Genetic tests demonstrate that the mutations in the Hoxb8 hexapeptide motif are affecting the function of other genes located in the Hoxb cluster. The expression pattern of these genes is not affected; rather it appears that the mutant Hoxb8 protein interferes with the function of other Hox genes by binding to their targets. Our findings suggest that the homeotic transformations result from altered DNA binding specificity of the mutant Hoxb8 protein, implicating the cooperative binding between Hoxb8 hexapeptide motif and cofactors as a critical element in the fine-tuning of Hoxb8 protein target specificity. This is the first time the function of the hexapeptide domain has been evaluated in vivo in mouse development.

  14. A long noncoding RNA maintains active chromatin to coordinate homeotic gene expression.

    PubMed

    Wang, Kevin C; Yang, Yul W; Liu, Bo; Sanyal, Amartya; Corces-Zimmerman, Ryan; Chen, Yong; Lajoie, Bryan R; Protacio, Angeline; Flynn, Ryan A; Gupta, Rajnish A; Wysocka, Joanna; Lei, Ming; Dekker, Job; Helms, Jill A; Chang, Howard Y

    2011-04-07

    The genome is extensively transcribed into long intergenic noncoding RNAs (lincRNAs), many of which are implicated in gene silencing. Potential roles of lincRNAs in gene activation are much less understood. Development and homeostasis require coordinate regulation of neighbouring genes through a process termed locus control. Some locus control elements and enhancers transcribe lincRNAs, hinting at possible roles in long-range control. In vertebrates, 39 Hox genes, encoding homeodomain transcription factors critical for positional identity, are clustered in four chromosomal loci; the Hox genes are expressed in nested anterior-posterior and proximal-distal patterns colinear with their genomic position from 3' to 5'of the cluster. Here we identify HOTTIP, a lincRNA transcribed from the 5' tip of the HOXA locus that coordinates the activation of several 5' HOXA genes in vivo. Chromosomal looping brings HOTTIP into close proximity to its target genes. HOTTIP RNA binds the adaptor protein WDR5 directly and targets WDR5/MLL complexes across HOXA, driving histone H3 lysine 4 trimethylation and gene transcription. Induced proximity is necessary and sufficient for HOTTIP RNA activation of its target genes. Thus, by serving as key intermediates that transmit information from higher order chromosomal looping into chromatin modifications, lincRNAs may organize chromatin domains to coordinate long-range gene activation. ©2011 Macmillan Publishers Limited. All rights reserved

  15. On the origin of class B floral homeotic genes: functional substitution and dominant inhibition in Arabidopsis by expression of an orthologue from the gymnosperm Gnetum.

    PubMed

    Winter, Kai-Uwe; Saedler, Heinz; Theissen, Günter

    2002-08-01

    Class B floral homeotic genes are involved in specifying stamen and petal identity in angiosperms (flowering plants). Here we report that gymnosperms, the closest relatives of the angiosperms, contain at least two different clades representing putative orthologues of class B genes, termed GGM2-like and DAL12-like genes. To obtain information about the functional conservation of the class B genes in seed plants, the representative of one of these clades from Gnetum, termed GGM2, was expressed under the control of the CaMV 35S promoter in Arabidopsis wild-type plants and in different class B mutants. In wild-type plants and in a conditional mutant grown at a permissive temperature, gain-of-function phenotypes were obtained in whorls 1 and 4, where class B genes are usually not expressed. In contrast, loss-of-function phenotypes were observed in whorls 2 and 3, where class B genes are expressed. In different class B gene null mutants of Arabidopsis, and in the conditional B mutant grown at the non-permissive temperature, a partial complementation of the mutant phenotype was obtained. In situ hybridization studies and class B gene promoter test fusion experiments demonstrated that the gain-of-function phenotypes are not due to an upregulation of the endogenous B genes from Arabidopsis, and hence probably involve interactions between GGM2 protein homodimers and class B protein target genes other than the Arabidopsis class B genes itself. To our knowledge, this is the first time that partial complementation of a homeotic mutant by an orthologous gene from a distantly related species has been reported. These data suggest that GGM2 has a function in the gymnosperm Gnetum which is related to that of class B floral organ identity genes of angiosperms. That function may be in the specification of male reproductive organ identity, and in distinguishing male from female reproductive organs.

  16. The ABCs of flower development: mutational analysis of AP1/FUL-like genes in rice provides evidence for a homeotic (A)-function in grasses.

    PubMed

    Wu, Feng; Shi, Xiaowei; Lin, Xuelei; Liu, Yuan; Chong, Kang; Theißen, Günter; Meng, Zheng

    2017-01-01

    The well-known ABC model describes the combinatorial interaction of homeotic genes in specifying floral organ identities. While the B- and C-functions are highly conserved throughout flowering plants and even in gymnosperms, the A-function, which specifies the identity of perianth organs (sepals and petals in eudicots), remains controversial. One reason for this is that in most plants that have been investigated thus far, with Arabidopsis being a remarkable exception, one does not find recessive mutants in which the identity of both types of perianth organs is affected. Here we report a comprehensive mutational analysis of all four members of the AP1/FUL-like subfamily of MADS-box genes in rice (Oryza sativa). We demonstrate that OsMADS14 and OsMADS15, in addition to their function of specifying meristem identity, are also required to specify palea and lodicule identities. Because these two grass-specific organs are very likely homologous to sepals and petals of eudicots, respectively, we conclude that there is a floral homeotic (A)-function in rice as defined previously. Together with other recent findings, our data suggest that AP1/FUL-like genes were independently recruited to fulfil the (A)-function in grasses and some eudicots, even though other scenarios cannot be excluded and are discussed. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

  17. Identification and expression of floral organ homeotic genes from Alpinia oblongifolia (Zingiberaceae).

    PubMed

    Xia, Yong-Mei; Gao, Xue-Mei; Li, Qing-Jun

    2009-02-01

    Current understanding of the classical ABC model of floral development has provided a new set of characters to evaluate floral evolution. However, what is still lacking is a clear assessment of this genetic program across monocots. Here, to investigate the evolution of members of class A and B genes in monocots, we report the sequence characteristic and transcript expression of three new MADS-box genes in Alpinia oblongifolia Hayata. Sequence and phylogenetic analysis reveals that these genes are FUL-like and AP3-like. Therefore, they were termed AoFL1, AoFL2 and AoAP3. AoFL1 contains the FUL motif, but AoFL2 lacks this motif. Their expression revealed by in situ hybridization may reflect the ancestral function of FUL-like genes in the specification of inflorescence and floral meristems. The AoAP3 gene contains two conserved motifs, the PI-derived and paleoAP3 motifs. The AoAP3 transcripts located to the corolla and stamen, and hybridization signals were detected in the central whorl. These expression patterns suggest that the functions of homologous organ identity genes are diversified in A. oblongifolia. The implications of these findings on the conservation of homologous gene function are discussed.

  18. Expression of the apoptosis gene reaper in homeotic, segmentation and other mutants in Drosophila.

    PubMed

    Zhai, Zongzhao; Stein, M A Sokrates; Lohmann, Ingrid

    2009-06-01

    Apoptosis is an essential process required for development and morphogenesis in metazoan organisms. The apoptosis pathway and cell death machinery have been extensively studied, but little is known how apoptosis genes are regulated in the course of development . In this study, we analyzed the transcriptional regulation of the pro-apoptotic gene reaper (rpr) by performing whole-mount in situ hybridization in embryos mutant for a number of transcription factor genes in Drosophila melanogaster. In sum, our data show that all factors studied have very specific temporal and spatial effects on rpr transcription . Thus, our results reinforce the concept that apoptosis is an essential process for morphogenesis and that apoptosis related genes very tight developmental factors identified in sculpting the morphology of various embryonic structures by modulating the apoptosis pathway.

  19. A novel role for the floral homeotic gene APETALA2 during Arabidopsis fruit development.

    PubMed

    Ripoll, Juan José; Roeder, Adrienne H K; Ditta, Gary S; Yanofsky, Martin F

    2011-12-01

    The majority of the Arabidopsis fruit comprises an ovary with three primary tissue types: the valves, the replum and the valve margins. The valves, which are derived from the ovary walls, are separated along their entire length by the replum. The valve margin, which consists of a separation layer and a lignified layer, forms as a narrow stripe of cells at the valve-replum boundaries. The valve margin identity genes are expressed at the valve-replum boundary and are negatively regulated by FUL and RPL in the valves and replum, respectively. In ful rpl double mutants, the valve margin identity genes become ectopically expressed, and, as a result, the entire outer surface of the ovary takes on valve margin identity. We carried out a genetic screen in this sensitized genetic background and identified a suppressor mutation that restored replum development. Surprisingly, we found that the corresponding suppressor gene was AP2, a gene that is well known for its role in floral organ identity, but whose role in Arabidopsis fruit development had not been previously described. We found that AP2 acts to prevent replum overgrowth by negatively regulating BP and RPL, two genes that normally act to promote replum formation. We also determined that AP2 acts to prevent overgrowth of the valve margin by repressing valve margin identity gene expression. We have incorporated AP2 into the current genetic network controlling fruit development in Arabidopsis.

  20. Two GATA transcription factors are downstream effectors of floral homeotic gene action in Arabidopsis.

    PubMed

    Mara, Chloe D; Irish, Vivian F

    2008-06-01

    Floral organogenesis is dependent on the combinatorial action of MADS-box transcription factors, which in turn control the expression of suites of genes required for growth, patterning, and differentiation. In Arabidopsis (Arabidopsis thaliana), the specification of petal and stamen identity depends on the action of two MADS-box gene products, APETALA3 (AP3) and PISTILLATA (PI). In a screen for genes whose expression was altered in response to the induction of AP3 activity, we identified GNC (GATA, nitrate-inducible, carbon-metabolism-involved) as being negatively regulated by AP3 and PI. The GNC gene encodes a member of the Arabidopsis GATA transcription factor family and has been implicated in the regulation of chlorophyll biosynthesis as well as carbon and nitrogen metabolism. In addition, we found that the GNC paralog, GNL (GNC-like), is also negatively regulated by AP3 and PI. Using chromatin immunoprecipitation, we showed that promoter sequences of both GNC and GNL are bound by PI protein, suggesting a direct regulatory interaction. Analyses of single and double gnc and gnl mutants indicated that the two genes share redundant roles in promoting chlorophyll biosynthesis, suggesting that in repressing GNC and GNL, AP3/PI have roles in negatively regulating this biosynthetic pathway in flowers. In addition, coexpression analyses of genes regulated by AP3, PI, GNC, and GNL indicate a complex regulatory interplay between these transcription factors in regulating a variety of light and nutrient responsive genes. Together, these results provide new insights into the transcriptional cascades controlling the specification of floral organ identities.

  1. Coordination of flower development by homeotic master regulators.

    PubMed

    Ito, Toshiro

    2011-02-01

    Floral homeotic genes encode transcription factors and act as master regulators of flower development. The homeotic protein complex is expressed in a specific whorl of the floral primordium and determines floral organ identity by the combinatorial action. Homeotic proteins continue to be expressed until late in flower development to coordinate growth and organogenesis. Recent genomic studies have shown that homeotic proteins bind thousands of target sites in the genome and regulate the expression of transcription factors, chromatin components and various proteins involved in hormone biosynthesis and signaling and other physiological activities. Further, homeotic proteins program chromatin to direct the developmental coordination of stem cell maintenance and differentiation in shaping floral organs. Copyright © 2010 Elsevier Ltd. All rights reserved.

  2. Structure and function of the homeotic gene complex (HOM-C) in the beetle, Tribolium castaneum.

    PubMed

    Beeman, R W; Stuart, J J; Brown, S J; Denell, R E

    1993-07-01

    The powerful combination of genetic, developmental and molecular approaches possible with the fruit fly, Drosophila melanogaster, has led to a profound understanding of the genetic control of early developmental events. However, Drosophila is a highly specialized long germ insect, and the mechanisms controlling its early development may not be typical of insects or Arthropods in general. The beetle, Tribolium castaneum, offers a similar opportunity to integrate high resolution genetic analysis with the developmental/molecular approaches currently used in other organisms. Early results document significant differences between insect orders in the functions of genes responsible for establishing developmental commitments.

  3. Structure and function of the homeotic gene complex (HOM-C) in the beetle, Tribolium castaneum

    NASA Technical Reports Server (NTRS)

    Beeman, R. W.; Stuart, J. J.; Brown, S. J.; Denell, R. E.; Spooner, B. S. (Principal Investigator)

    1993-01-01

    The powerful combination of genetic, developmental and molecular approaches possible with the fruit fly, Drosophila melanogaster, has led to a profound understanding of the genetic control of early developmental events. However, Drosophila is a highly specialized long germ insect, and the mechanisms controlling its early development may not be typical of insects or Arthropods in general. The beetle, Tribolium castaneum, offers a similar opportunity to integrate high resolution genetic analysis with the developmental/molecular approaches currently used in other organisms. Early results document significant differences between insect orders in the functions of genes responsible for establishing developmental commitments.

  4. Structure and function of the homeotic gene complex (HOM-C) in the beetle, Tribolium castaneum

    NASA Technical Reports Server (NTRS)

    Beeman, R. W.; Stuart, J. J.; Brown, S. J.; Denell, R. E.; Spooner, B. S. (Principal Investigator)

    1993-01-01

    The powerful combination of genetic, developmental and molecular approaches possible with the fruit fly, Drosophila melanogaster, has led to a profound understanding of the genetic control of early developmental events. However, Drosophila is a highly specialized long germ insect, and the mechanisms controlling its early development may not be typical of insects or Arthropods in general. The beetle, Tribolium castaneum, offers a similar opportunity to integrate high resolution genetic analysis with the developmental/molecular approaches currently used in other organisms. Early results document significant differences between insect orders in the functions of genes responsible for establishing developmental commitments.

  5. Variation and selection at the CAULIFLOWER floral homeotic gene accompanying the evolution of domesticated Brassica oleracea.

    PubMed Central

    Purugganan, M D; Boyles, A L; Suddith, J I

    2000-01-01

    The evolution of plant morphologies during domestication events provides clues to the origin of crop species and the evolutionary genetics of structural diversification. The CAULIFLOWER gene, a floral regulatory locus, has been implicated in the cauliflower phenotype in both Arabidopsis thaliana and Brassica oleracea. Molecular population genetic analysis indicates that alleles carrying a nonsense mutation in exon 5 of the B. oleracea CAULIFLOWER (BoCAL) gene are segregating in both wild and domesticated B. oleracea subspecies. Alleles carrying this nonsense mutation are nearly fixed in B. oleracea ssp. botrytis (domestic cauliflower) and B. oleracea ssp. italica (broccoli), both of which show evolutionary modifications of inflorescence structures. Tests for selection indicate that the pattern of variation at this locus is consistent with positive selection at BoCAL in these two subspecies. This nonsense polymorphism, however, is also present in both B. oleracea ssp. acephala (kale) and B. oleracea ssp. oleracea (wild cabbage). These results indicate that specific alleles of BoCAL were selected by early farmers during the domestication of modified inflorescence structures in B. oleracea. PMID:10835404

  6. Activation of the Arabidopsis B class homeotic genes by APETALA1.

    PubMed

    Ng, M; Yanofsky, M F

    2001-04-01

    Proper development of petals and stamens in Arabidopsis flowers requires the activities of APETALA3 (AP3) and PISTILLATA (PI), whose transcripts can be detected in the petal and stamen primordia. Localized expression of AP3 and PI requires the activities of at least three genes: APETALA1 (AP1), LEAFY (LFY), and UNUSUAL FLORAL ORGANS (UFO). It has been proposed that UFO provides spatial cues and that LFY specifies competence for AP3 and PI expression in the developing flower. To understand the epistatic relationship among AP1, LFY, and UFO in regulating AP3 and PI expression, we generated two versions of AP1 that have strong transcriptional activation potential. Genetic and molecular analyses of transgenic plants expressing these activated AP1 proteins show that the endogenous AP1 protein acts largely as a transcriptional activator in vivo and that AP1 specifies petals by regulating the spatial domains of AP3 and PI expression through UFO.

  7. Hidden Variability of Floral Homeotic B Genes in Solanaceae Provides a Molecular Basis for the Evolution of Novel Functions[C][W

    PubMed Central

    Geuten, Koen; Irish, Vivian

    2010-01-01

    B-class MADS box genes specify petal and stamen identities in several core eudicot species. Members of the Solanaceae possess duplicate copies of these genes, allowing for diversification of function. To examine the changing roles of such duplicate orthologs, we assessed the functions of B-class genes in Nicotiana benthamiana and tomato (Solanum lycopersicum) using virus-induced gene silencing and RNA interference approaches. Loss of function of individual duplicates can have distinct phenotypes, yet complete loss of B-class gene function results in extreme homeotic transformations of petal and stamen identities. We also show that these duplicate gene products have qualitatively different protein–protein interaction capabilities and different regulatory roles. Thus, compensatory changes in B-class MADS box gene duplicate function have occurred in the Solanaceae, in that individual gene roles are distinct, but their combined functions are equivalent. Furthermore, we show that species-specific differences in the stamen regulatory network are associated with differences in the expression of the microRNA miR169. Whereas there is considerable plasticity in individual B-class MADS box transcription factor function, there is overall conservation in the roles of the multimeric MADS box B-class protein complexes, providing robustness in the specification of petal and stamen identities. Such hidden variability in gene function as we observe for individual B-class genes can provide a molecular basis for the evolution of regulatory functions that result in novel morphologies. PMID:20807882

  8. Knockdown of spalt function by RNAi causes de-repression of Hox genes and homeotic transformations in the crustacean Artemia franciscana.

    PubMed

    Copf, Tijana; Rabet, Nicolas; Averof, Michalis

    2006-10-01

    Hox genes play a central role in the specification of distinct segmental identities in the body of arthropods. The specificity of Hox genes depends on their restricted expression domains, their interaction with specific cofactors and selectivity for particular target genes. spalt genes are associated with the function of Hox genes in diverse species, but the nature of this association varies: in some cases, spalt collaborates with Hox genes to specify segmental identities, in others, it regulates Hox gene expression or acts as their target. Here we study the role of spalt in the branchiopod crustacean Artemia franciscana. We find that Artemia spalt is expressed in the pre-segmental 'growth zone' and in stripes in each of the trunk (thoracic, genital and post-genital) segments that emerge from this zone. Using RNA interference (RNAi), we show that knocking down the expression of spalt has pleiotropic effects, which include thoracic to genital (T-->G), genital to thoracic (G-->T) and post-genital to thoracic (PG-->T) homeotic transformations. These transformations are associated with a stochastic de-repression of Hox genes in the corresponding segments of RNAi-treated animals (AbdB for T-->G and Ubx/AbdA for G-->T and PG-->T transformations). We discuss a possible role of spalt in the maintenance of Hox gene repression in Artemia and in other animals.

  9. The tomato floral homeotic protein FBP1-like gene, SlGLO1, plays key roles in petal and stamen development

    PubMed Central

    Guo, Xuhu; Hu, Zongli; Yin, Wencheng; Yu, Xiaohui; Zhu, Zhiguo; Zhang, Jianling; Chen, Guoping

    2016-01-01

    MADS-box transcription factors play important role in plant growth and development, especially floral organ identities. In our study, a MADS-box gene SlGLO1- tomato floral homeotic protein FBP1-like gene was isolated. Its tissue-specific expression profile analysis showed that SlGLO1 was highly expressed in petals and stamens. RNAi (RNA interference) repression of SlGLO1 resulted in floral organ abnormal phenotypes, including green petals with shorter size, and aberrant carpelloid stamens. SlGLO1-silenced lines are male sterile. Total chlorophyll content was increased and chlorophyll biosynthetic genes were significantly up-regulated in SlGLO1-silenced petals and stamens. Furthermore, B-class genes expression analysis indicated that the repressed function of SlGLO1 led to the enhanced expression of TAP3 and the down-regulation of TPI in the petals and stamens, while the expression of TM6 was reduced in petals and increased in stamens and carpels of SlGLO1-RNAi plants. Additionally, pollen grains of transgenic lines were aberrant and failed to germinate and tomato pollen-specific genes were down-regulated by more than 90% in SlGLO1-silenced lines. These results suggest that SlGLO1 plays important role in regulating plant floral organ and pollen development in tomato. PMID:26842499

  10. The tomato floral homeotic protein FBP1-like gene, SlGLO1, plays key roles in petal and stamen development.

    PubMed

    Guo, Xuhu; Hu, Zongli; Yin, Wencheng; Yu, Xiaohui; Zhu, Zhiguo; Zhang, Jianling; Chen, Guoping

    2016-02-04

    MADS-box transcription factors play important role in plant growth and development, especially floral organ identities. In our study, a MADS-box gene SlGLO1- tomato floral homeotic protein FBP1-like gene was isolated. Its tissue-specific expression profile analysis showed that SlGLO1 was highly expressed in petals and stamens. RNAi (RNA interference) repression of SlGLO1 resulted in floral organ abnormal phenotypes, including green petals with shorter size, and aberrant carpelloid stamens. SlGLO1-silenced lines are male sterile. Total chlorophyll content was increased and chlorophyll biosynthetic genes were significantly up-regulated in SlGLO1-silenced petals and stamens. Furthermore, B-class genes expression analysis indicated that the repressed function of SlGLO1 led to the enhanced expression of TAP3 and the down-regulation of TPI in the petals and stamens, while the expression of TM6 was reduced in petals and increased in stamens and carpels of SlGLO1-RNAi plants. Additionally, pollen grains of transgenic lines were aberrant and failed to germinate and tomato pollen-specific genes were down-regulated by more than 90% in SlGLO1-silenced lines. These results suggest that SlGLO1 plays important role in regulating plant floral organ and pollen development in tomato.

  11. Homeotic function of Drosophila Bithorax-complex miRNAs mediates fertility by restricting multiple Hox genes and TALE cofactors in the CNS.

    PubMed

    Garaulet, Daniel L; Castellanos, Monica C; Bejarano, Fernando; Sanfilippo, Piero; Tyler, David M; Allan, Douglas W; Sánchez-Herrero, Ernesto; Lai, Eric C

    2014-06-23

    The Drosophila Bithorax complex (BX-C) Hox cluster contains a bidirectionally transcribed miRNA locus, and a deletion mutant (Δmir) lays no eggs and is completely sterile. We show these miRNAs are expressed and active in distinct spatial registers along the anterior-posterior axis in the CNS. Δmir larvae derepress a network of direct homeobox gene targets in the posterior ventral nerve cord (VNC), including BX-C genes and their TALE cofactors. These are phenotypically critical targets, because sterility of Δmir mutants was substantially rescued by heterozygosity of these genes. The posterior VNC contains Ilp7+ oviduct motoneurons, whose innervation and morphology are defective in Δmir females, and substantially rescued by heterozygosity of Δmir targets, especially within the BX-C. Collectively, we reveal (1) critical roles for Hox miRNAs that determine segment-specific expression of homeotic genes, which are not masked by transcriptional regulation; and (2) that BX-C miRNAs are essential for neural patterning and reproductive behavior. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Homeotic function of Drosophila Bithorax-Complex miRNAs mediates fertility by restricting multiple Hox genes and TALE cofactors in the central nervous system

    PubMed Central

    Garaulet, Daniel L.; Castellanos, Monica; Bejarano, Fernando; Sanfilippo, Piero; Tyler, David M.; Allan, Douglas W.; Sánchez-Herrero, Ernesto; Lai, Eric C.

    2014-01-01

    The Drosophila Bithorax-Complex (BX-C) Hox cluster contains a bidirectionally-transcribed miRNA locus, and a deletion mutant (∆mir) lays no eggs and is completely sterile. We show these miRNAs are expressed and active in distinct spatial registers along the anterior-posterior axis in the central nervous system. ∆mir larvae derepress a network of direct homeobox gene targets in the posterior ventral nerve cord (VNC), including BX-C genes and their TALE cofactors. These are phenotypically critical targets, since sterility of ∆mir mutants was substantially rescued by heterozygosity of these genes. The posterior VNC contains Ilp7+ oviduct motoneurons, whose innervation and morphology are defective in ∆mir females, and substantially rescued by heterozygosity of ∆mir targets, especially within the BX-C. Collectively, we reveal (1) critical roles for Hox miRNAs that determine segment-specific expression of homeotic genes, which are not masked by transcriptional regulation, and (2) that BX-C miRNAs are essential for neural patterning and reproductive behavior. PMID:24909902

  13. Identification of target genes regulated by homeotic proteins in Drosophila melanogaster through genetic selection of Ultrabithorax protein-binding sites in yeast

    SciTech Connect

    Mastick, G.S.; McKay, R.; Oligino, T.

    1995-01-01

    A method based on the transcriptional activation of a selectable reporter in yeast cells was used to identify genes regulated by the Utrabithorax homeoproteins in Drosophila melanogaster. Fifty-three DNA fragments that can mediate activation by UBX isoform Ia in this test were recovered after screening 15% of the Drosophila genome. Half of these fragments represent single-copy sequences in the genome. Six single-copy fragments were investigated in detail, and each was found to reside near a transcription unit whose expression in the embryo is segmentally modulated as expected for targets of homeotic genes. Four of these putative target genes are expressed in patterns that suggest roles in the development of regional specializations within mesoderm derivatives; in three cases these expression patterns depend on Ultrabithorax function. Extrapolation from this pilot study indicates that 85-170 candidate target genes can be identified by screening the entire Drosophila genome with UBX isoform Ia. With appropriate modifications, this approach should be applicable to other transcriptional regulators in diverse organisms. 69 refs., 9 figs., 2 tabs.

  14. spalt encodes an evolutionarily conserved zinc finger protein of novel structure which provides homeotic gene function in the head and tail region of the Drosophila embryo.

    PubMed Central

    Kühnlein, R P; Frommer, G; Friedrich, M; Gonzalez-Gaitan, M; Weber, A; Wagner-Bernholz, J F; Gehring, W J; Jäckle, H; Schuh, R

    1994-01-01

    The region specific homeotic gene spalt (sal) of Drosophila melanogaster promotes the specification of terminal pattern elements as opposed to segments in the trunk. Our results show that the previously reported sal transcription unit was misidentified. Based on P-element mediated germ line transformation and DNA sequence analysis of sal mutant alleles, we identified the transcription unit that carries sal function. sal is located close to the misidentified transcription unit, and it is expressed in similar temporal and spatial patterns during embryogenesis. The sal gene encodes a zinc finger protein of novel structure composed of three widely spaced 'double zinc finger' motifs of internally conserved sequences and a single zinc finger motif of different sequence. Antibodies produced against the sal protein show that sal is first expressed at the blastoderm stage and later in restricted areas of the embryonic nervous system as well as in the developing trachea. The antibodies detect sal homologous proteins in corresponding spatial and temporal patterns in the embryos of related insect species. Sequence analysis of the sal gene of Drosophila virilis, a species which is phylogenetically separated by approximately 60 million years, suggests that the sal function is conserved during evolution, consistent with its proposed role in head formation during arthropod evolution. Images PMID:7905822

  15. orf260cra, a novel mitochondrial gene, is associated with the homeotic transformation of stamens into pistil-like structures (pistillody) in alloplasmic wheat.

    PubMed

    Zhu, Ye; Saraike, Tatsunori; Yamamoto, Yuko; Hagita, Hiroko; Takumi, Shigeo; Murai, Koji

    2008-11-01

    Homeotic transformation of stamens into pistil-like structures (pistillody) can occur in cytoplasmic substitution (alloplasmic) lines of bread wheat (Triticum aestivum) that have the cytoplasm of the related species, Aegilops crassa. Previously we showed that pistillody results from altered patterns of expression of class B MADS-box genes mediated by mitochondrial gene(s) in the Ae. crassa cytoplasm. The wheat cultivar Chinese Spring does not show pistillody when Ae. crassa cytoplasm is introduced. The absence of an effect is due to a single dominant gene (designated Rfd1) located on the long arm of chromosome 7B. To identify the mitochondrial gene involved in pistillody induction, we performed a subtraction analysis using cDNAs derived from young spikes of a pistillody line and a normal line. We found that mitochondrial cDNA clone R04 was abundant in the young spikes of the pistillody line but was down-regulated in the normal line that carried nuclear Rfd1. Sequencing of the full-length cDNA corresponding to clone R04 showed that two genes were present, cox I (cytochrome c oxidase subunit I) and orf260(cra). orf260(cra) shows high sequence similarity to orf256, the T. timopheevii mitochondrial gene responsible for cytoplasmic male sterility (CMS). orf260(cra) was also present in the cytoplasms of Ae. juvenalis and Ae. vavilovii, which induce pistillody, but not in the cytoplasms of other species not associated with pistillody. Furthermore, Western blot analysis revealed that the ORF260cra protein was more abundant in the pistillody line than in the normal line. We suggest therefore that orf260(cra) is associated with pistillody induction.

  16. Analysis of the APETALA3- and PISTILLATA-like genes in Hedyosmum orientale (Chloranthaceae) provides insight into the evolution of the floral homeotic B-function in angiosperms.

    PubMed

    Liu, Shujun; Sun, Yonghua; Du, Xiaoqiu; Xu, Qijiang; Wu, Feng; Meng, Zheng

    2013-11-01

    According to the floral ABC model, B-function genes appear to play a key role in the origin and diversification of the perianth during the evolution of angiosperms. The basal angiosperm Hedyosmum orientale (Chloranthaceae) has unisexual inflorescences associated with a seemingly primitive reproductive morphology and a reduced perianth structure in female flowers. The aim of this study was to investigate the nature of the perianth and the evolutionary state of the B-function programme in this species. A series of experiments were conducted to characterize B-gene homologues isolated from H. orientale, including scanning electron microscopy to observe the development of floral organs, phylogenetic analysis to reconstruct gene evolutionary history, reverse transcription-PCR, quantitative real-time PCR and in situ hybridization to identify gene expression patterns, the yeast two-hybrid assay to explore protein dimerization affinities, and transgenic analyses in Arabidopsis thaliana to determine activities of the encoded proteins. The expression of HoAP3 genes was restricted to stamens, whereas HoPI genes were broadly expressed in all floral organs. HoAP3 was able to partially restore the stamen but not petal identity in Arabidopsis ap3-3 mutants. In contrast, HoPI could rescue aspects of both stamen and petal development in Arabidopsis pi-1 mutants. When the complete C-terminal sequence of HoPI was deleted, however, no or weak transgenic phenotypes were observed and homodimerization capability was completely abolished. The results suggest that Hedyosmum AP3-like genes have an ancestral function in specifying male reproductive organs, and that the activity of the encoded PI-like proteins is highly conserved between Hedyosmum and Arabidopsis. Moreover, there is evidence that the C-terminal region is important for the function of HoPI. Our findings indicate that the development of the proposed perianth in Hedyosmum does not rely on the B homeotic function.

  17. Analysis of the APETALA3- and PISTILLATA-like genes in Hedyosmum orientale (Chloranthaceae) provides insight into the evolution of the floral homeotic B-function in angiosperms

    PubMed Central

    Liu, Shujun; Sun, Yonghua; Du, Xiaoqiu; Xu, Qijiang; Wu, Feng; Meng, Zheng

    2013-01-01

    Background and Aims According to the floral ABC model, B-function genes appear to play a key role in the origin and diversification of the perianth during the evolution of angiosperms. The basal angiosperm Hedyosmum orientale (Chloranthaceae) has unisexual inflorescences associated with a seemingly primitive reproductive morphology and a reduced perianth structure in female flowers. The aim of this study was to investigate the nature of the perianth and the evolutionary state of the B-function programme in this species. Methods A series of experiments were conducted to characterize B-gene homologues isolated from H. orientale, including scanning electron microscopy to observe the development of floral organs, phylogenetic analysis to reconstruct gene evolutionary history, reverse transcription–PCR, quantitative real-time PCR and in situ hybridization to identify gene expression patterns, the yeast two-hybrid assay to explore protein dimerization affinities, and transgenic analyses in Arabidopsis thaliana to determine activities of the encoded proteins. Key Results The expression of HoAP3 genes was restricted to stamens, whereas HoPI genes were broadly expressed in all floral organs. HoAP3 was able to partially restore the stamen but not petal identity in Arabidopsis ap3-3 mutants. In contrast, HoPI could rescue aspects of both stamen and petal development in Arabidopsis pi-1 mutants. When the complete C-terminal sequence of HoPI was deleted, however, no or weak transgenic phenotypes were observed and homodimerization capability was completely abolished. Conclusions The results suggest that Hedyosmum AP3-like genes have an ancestral function in specifying male reproductive organs, and that the activity of the encoded PI-like proteins is highly conserved between Hedyosmum and Arabidopsis. Moreover, there is evidence that the C-terminal region is important for the function of HoPI. Our findings indicate that the development of the proposed perianth in Hedyosmum does

  18. Heterotopic expression of B-class floral homeotic genes PISTILLATA/GLOBOSA supports a modified model for crocus (Crocus sativus L.) flower formation.

    PubMed

    Kalivas, Apostolos; Pasentsis, Konstantinos; Polidoros, Alexios N; Tsaftaris, Athanasios S

    2007-04-01

    For uncovering and understanding the molecular mechanisms controlling flower development in cultivated Crocus sativus and particularly the transformation of sepals in outer whorl (whorl 1) tepals, we have cloned and characterized the expression of a family of five PISTILLATA/GLOBOSA-like (PI/GLO-like) MADS-box genes expressed in the C. sativus flower. The deduced amino acid sequences of the coded proteins indicated high homology with members of the MADS-box family of transcription factors, and particularly with other members of the PI/GLO family of MADS-box proteins that control floral organ identity. PI/GLO expression studies in cultivated C. sativus uncover the presence of PI/GLO transcripts not only in the second and third whorls of flower organs as expected, but also in the outer whorl tepals that are the sepals in most typical flowers. This heterotopic expression of both B-class genes: PI/GLO and AP3/DEF, known to form heterodimers for stamens and petals (petaloid inner whor l-whorl 2-tepals in C. sativus), explains the homeotic transformation of sepals into outer whorl tepals in this species. Analysis of PI/GLO sequences from C. sativus for putative targets to known micro-RNAs (miRNAs) showed that the target site for ath-miRNA167 found in Arabidopsis thaliana PI is not present in C. sativus, however, the PI/GLO sequences may be regulated by an ath-miRNA163.

  19. Rice MADS6 Interacts with the Floral Homeotic Genes SUPERWOMAN1, MADS3, MADS58, MADS13, and DROOPING LEAF in Specifying Floral Organ Identities and Meristem Fate[C][W][OA

    PubMed Central

    Li, Haifeng; Liang, Wanqi; Hu, Yun; Zhu, Lu; Yin, Changsong; Xu, Jie; Dreni, Ludovico; Kater, Martin M.; Zhang, Dabing

    2011-01-01

    AGAMOUS-LIKE6 (AGL6) genes play essential roles in flower development, but whether and how they work with floral organ identity genes remain less understood. Here, we describe interactions of the rice (Oryza sativa) AGL6 gene MADS6 with other rice floral homeotic genes in flower development. Genetic analyses revealed that MADS6 specifies the identity of the three inner whorls and floral meristem determinacy redundantly with SUPERWOMAN1/MADS16 (B-gene) or MADS3 (C-gene). MADS6 was shown to define carpel/ovule development and floral determinacy by interacting with MADS13 (D-gene) and control the palea and floral meristem identities together with the YABBY gene DROOPING LEAF. Expression analyses revealed that the transcript levels of six B-, C-, and E-class genes were reduced in mads6-1 at the early flower developmental stage, suggesting that MADS6 is a key regulator of early flower development. Moreover, MADS6 can directly bind to a putative regulatory motif on MADS58 (C-gene), and mads6-1 mads58 displayed phenotypes similar to that of mads6-1. These results suggest that MADS6 is a key player in specifying flower development via interacting with other floral homeotic genes in rice, thus providing new insights into the mechanism by which flower development is controlled. PMID:21784949

  20. Expression of homeotic genes Hoxa3, Hoxb3, Hoxd3 and Hoxc4 is decreased in the lungs but not in the hearts of adriamycin-exposed mice.

    PubMed

    Calonge, W M; Martinez, L; Lacadena, J; Fernandez-Dumont, V; Matesanz, R; Tovar, J A

    2007-05-01

    Exposure of rat and mouse embryos to adriamycin (doxorubicin chlorhydrate) induces esophageal atresia (EA) and VACTERL association. Sonic hedgehog (Shh) and Gli2/Gli3 pathways are involved in these conditions and knockout mice for homeotic Hox genes Hoxa3, Hoxb3, Hoxc3, Hoxc4 and Hoxa5 show phenotypes with some of the associated VACTERL features. This study aims at evaluating the possible influence of Hoxa3, Hoxb3, Hoxd3 and Hoxc4 as upstream regulators of this complex signalling. Pregnant mice were exposed either to 4 mg/kg of adriamycin (EA group) or vehicle (controls) on embryonic days 7.5 and 8.5. Embryos were recovered at four endpoints (E12.5-E15.5) and randomly assigned for immunohistochemical or molecular biology studies. Lungs and hearts were separately harvested and processed for Hoxa3, Hoxb3, Hoxd3 and Hoxc4 quantitative RT-PCR measurements. Antibodies for Hoxa3, Hoxb3 and Hoxd3 proteins were used for immunohistochemical studies. RT-PCR studies showed a drastic and statistically significant decrease of the four genes in the lungs of EA mice when compared to controls, with a slight recovery from E15.5. Hearts of both groups showed a similar expression of all the genes throughout gestation. Control embryos expressed the hox3 paralogous genes in heart, skin, foregut derivatives and their surrounding mesoderm through E12.5-E15.5 whereas adriamycin-exposed embryos showed a severe decrease in expression of these three proteins in the same tissues but not in the heart. Adriamycin drastically reduced the expression of Hoxa3, Hoxb3, Hoxd3 and Hoxc4 in mice embryonic lungs. Their expression in the heart did not seem to be influenced by adriamycin in this experimental setting.

  1. Expression levels of meristem identity and homeotic genes are modified by nuclear-mitochondrial interactions in alloplasmic male-sterile lines of Brassica napus.

    PubMed

    Teixeira, Rita Teresa; Farbos, Isabelle; Glimelius, Kristina

    2005-06-01

    Homeotic conversions of anthers were found in cytoplasmic male sterile (CMS) plants of Brassica napus derived from somatic hybrids of B. napus and Arabidopsis thaliana. CMS line flowers displayed petals reduced in size and width and stamens replaced by carpelloid structures. In order to investigate when these developmental aberrations appeared, flower development was analysed histologically, ultrastructurally and molecularly. Disorganized cell divisions were detected in the floral meristems of the CMS lines at stage 4. As CMS is associated with mitochondrial aberrations, ultrastructural analysis of the mitochondria in the floral meristems was performed. Two mitochondrial populations were found in the CMS lines. One type had disrupted cristae, while the other resembled mitochondria typical of B. napus. Furthermore, expression patterns of genes expressed in particular floral whorls were determined. In spite of the aberrant development of the third whorl organs, BnAP3 was expressed as in B. napus during the first six stages of development. However, the levels of BnPI were reduced. At later developmental stages, the expression of both BnAP3 and BnPI was strongly reduced. Interestingly the expression levels of genes responsible for AP3 and PI activation such as LFY, UFO and ASK1 were higher in the CMS lines, which indicates that activation of B-genes in the CMS lines does not occur as in B. napus. Disrupted and dysfunctional mitochondria seem to be one of the first aberrations manifested in CMS which result in a retrograde influence of the expression levels of genes responsible for the second and third whorl organ differentiation.

  2. The product of the murine homolog of the Drosophila extra sex combs gene displays transcriptional repressor activity.

    PubMed Central

    Denisenko, O N; Bomsztyk, K

    1997-01-01

    The heterogeneous nuclear ribonucleoprotein K protein represents a novel class of proteins that may act as docking platforms that orchestrate cross-talk among molecules involved in signal transduction and gene expression. Using a fragment of K protein as bait in the yeast two-hybrid screen, we isolated a cDNA that encodes a protein whose primary structure has extensive similarity to the Drosophila melanogaster extra sex combs (esc) gene product, Esc, a putative silencer of homeotic genes. The cDNA that we isolated is identical to the cDNA of the recently positionally cloned mouse embryonic ectoderm development gene, eed. Like Esc, Eed contains six WD-40 repeats in the C-terminal half of the protein and is thought to repress homeotic gene expression during mouse embryogenesis. Eed binds to K protein through a domain in its N terminus, but interestingly, this domain is not found in the Drosophila Esc. Gal4-Eed fusion protein represses transcription of a reporter gene driven by a promoter that contains Gal4-binding DNA elements. Eed also represses transcription when recruited to a target promoter by Gal4-K protein. Point mutations within the eed gene that are responsible for severe embryonic development abnormalities abolished the transcriptional repressor activity of Eed. Results of this study suggest that Eed-restricted homeotic gene expression during embryogenesis reflects the action of Eed as a transcriptional repressor. The Eed-mediated transcriptional effects are likely to reflect the interaction of Eed with multiple molecular partners, including K protein. PMID:9234727

  3. DNA replication, development and cancer: a homeotic connection?

    PubMed

    Falaschi, Arturo; Abdurashidova, Gulnara; Biamonti, Giuseppe

    2010-02-01

    The homeotic proteins are transcription factors, highly conserved in metazoan organisms, exerting a pivotal role in development and differentiation. They individually display a loose specificity for the DNA sequence they can bind, but operate mainly in multi-molecular associations that assure their target and function specificity. Homeotic proteins are known to play a role in the positive or negative regulation of cell proliferation. Furthermore, many homeotic proteins are actually proto-oncogenes, since different translocations involving their genes cause tumors, particularly in the hematopoietic system. A one-hybrid screen to detect proteins with affinity for the lamin B2 replication origin identified three homeotic proteins, namely HoxA13, HoxC10 and HoxC13. Recent data demonstrate that the HoxC13 oncoprotein specifically associates with replication foci and binds in vitro and in vivo to several human DNA replication origins. Moreover, Hox proteins interact with geminin, a regulator of cell cycle progression, and control the interaction of this protein with the DNA replication licensing factor Ctd1. Thus, the homeotic proteins, by participating directly in the function of DNA replication origins, may provide a direct link between the accurate regulation of DNA replication required by the morphogenetic program and the deregulation of this process typical of cancer.

  4. Two AGAMOUS-like MADS-box genes from Taihangia rupestris (Rosaceae) reveal independent trajectories in the evolution of class C and class D floral homeotic functions.

    PubMed

    Lü, Shanhua; Du, Xiaoqiu; Lu, Wenliang; Chong, Kang; Meng, Zheng

    2007-01-01

    Duplicate genes may be retained by sub- and/or neofunctionalization through changes in gene expression and/or coding sequence, and therefore have the potential to contribute to the genetic robustness and diversification of an organism. In this study, two MADS-box genes were isolated from Taihangia rupestris, a core eudicot species belonging to the Rosaceae. Sequence and phylogenetic analyses revealed that they are clade members of the euAG and PLE lineages, respectively, and hence the two genes are named TrAG (Taihangia rupestris AGAMOUS) and TrSHP (Taihangia rupestris SHATTERPROOF). Southern blot analysis shows that TrSHP is a single-copy gene in the T. rupestris genome. In situ hybridization analyses show that both TrAG and TrSHP are mainly expressed in the stamens, carpels, and ovules. When the stamen primordia are firstly observed, TrAG is initially expressed in the floral meristem domain that will initiate stamens and carpels. In contrast, no TrSHP signal is observed at this developmental stage. At late stages of carpel development, TrAG expression is detected in the ovules, ovaries, and developing styles and stigmas, whereas TrSHP expression is tightly restricted to the ovules. The transgenic Arabidopsis plants containing 35S::TrAG and 35S::TrSHP, respectively, showed similar phenotypes, including homeotic conversions of sepals into carpelloid structures bearing ovules and petals into staminoid organs, and the fruits shattering prematurely along the dehiscence zone. In addition, the phenotype of the transgenic 35S::TrSHP Arabidopsis plants revealed that perianth abscission was inhibited. Yeast two-hybrid assays indicated that TrAG can interact with TrSEP3, whereas TrSHP cannot. The data suggest that the euAG and PLE paralogs, TrAG and TrSHP, may have subfunctionalized and/or neofunctionalized through changes in expression patterns and accumulating variations in the coding regions. Taking these findings together with those available expression and functional

  5. Duplication and diversification in the APETALA1/FRUITFULL floral homeotic gene lineage: implications for the evolution of floral development.

    PubMed Central

    Litt, Amy; Irish, Vivian F

    2003-01-01

    Phylogenetic analyses of angiosperm MADS-box genes suggest that this gene family has undergone multiple duplication events followed by sequence divergence. To determine when such events have taken place and to understand the relationships of particular MADS-box gene lineages, we have identified APETALA1/FRUITFULL-like MADS-box genes from a variety of angiosperm species. Our phylogenetic analyses show two gene clades within the core eudicots, euAP1 (including Arabidopsis APETALA1 and Antirrhinum SQUAMOSA) and euFUL (including Arabidopsis FRUITFULL). Non-core eudicot species have only sequences similar to euFUL genes (FUL-like). The predicted protein products of euFUL and FUL-like genes share a conserved C-terminal motif. In contrast, predicted products of members of the euAP1 gene clade contain a different C terminus that includes an acidic transcription activation domain and a farnesylation signal. Sequence analyses indicate that the euAP1 amino acid motifs may have arisen via a translational frameshift from the euFUL/FUL-like motif. The euAP1 gene clade includes key regulators of floral development that have been implicated in the specification of perianth identity. However, the presence of euAP1 genes only in core eudicots suggests that there may have been changes in mechanisms of floral development that are correlated with the fixation of floral structure seen in this clade. PMID:14573491

  6. Positive selection and ancient duplications in the evolution of class B floral homeotic genes of orchids and grasses.

    PubMed

    Mondragón-Palomino, Mariana; Hiese, Luisa; Härter, Andrea; Koch, Marcus A; Theissen, Günter

    2009-04-21

    Positive selection is recognized as the prevalence of nonsynonymous over synonymous substitutions in a gene. Models of the functional evolution of duplicated genes consider neofunctionalization as key to the retention of paralogues. For instance, duplicate transcription factors are specifically retained in plant and animal genomes and both positive selection and transcriptional divergence appear to have played a role in their diversification. However, the relative impact of these two factors has not been systematically evaluated. Class B MADS-box genes, comprising DEF-like and GLO-like genes, encode developmental transcription factors essential for establishment of perianth and male organ identity in the flowers of angiosperms. Here, we contrast the role of positive selection and the known divergence in expression patterns of genes encoding class B-like MADS-box transcription factors from monocots, with emphasis on the family Orchidaceae and the order Poales. Although in the monocots these two groups are highly diverse and have a strongly canalized floral morphology, there is no information on the role of positive selection in the evolution of their distinctive flower morphologies. Published research shows that in Poales, class B-like genes are expressed in stamens and in lodicules, the perianth organs whose identity might also be specified by class B-like genes, like the identity of the inner tepals of their lily-like relatives. In orchids, however, the number and pattern of expression of class B-like genes have greatly diverged. The DEF-like genes from Orchidaceae form four well-supported, ancient clades of orthologues. In contrast, orchid GLO-like genes form a single clade of ancient orthologues and recent paralogues. DEF-like genes from orchid clade 2 (OMADS3-like genes) are under less stringent purifying selection than the other orchid DEF-like and GLO-like genes. In comparison with orchids, purifying selection was less stringent in DEF-like and GLO-like genes

  7. Positive selection and ancient duplications in the evolution of class B floral homeotic genes of orchids and grasses

    PubMed Central

    Mondragón-Palomino, Mariana; Hiese, Luisa; Härter, Andrea; Koch, Marcus A; Theißen, Günter

    2009-01-01

    Background Positive selection is recognized as the prevalence of nonsynonymous over synonymous substitutions in a gene. Models of the functional evolution of duplicated genes consider neofunctionalization as key to the retention of paralogues. For instance, duplicate transcription factors are specifically retained in plant and animal genomes and both positive selection and transcriptional divergence appear to have played a role in their diversification. However, the relative impact of these two factors has not been systematically evaluated. Class B MADS-box genes, comprising DEF-like and GLO-like genes, encode developmental transcription factors essential for establishment of perianth and male organ identity in the flowers of angiosperms. Here, we contrast the role of positive selection and the known divergence in expression patterns of genes encoding class B-like MADS-box transcription factors from monocots, with emphasis on the family Orchidaceae and the order Poales. Although in the monocots these two groups are highly diverse and have a strongly canalized floral morphology, there is no information on the role of positive selection in the evolution of their distinctive flower morphologies. Published research shows that in Poales, class B-like genes are expressed in stamens and in lodicules, the perianth organs whose identity might also be specified by class B-like genes, like the identity of the inner tepals of their lily-like relatives. In orchids, however, the number and pattern of expression of class B-like genes have greatly diverged. Results The DEF-like genes from Orchidaceae form four well-supported, ancient clades of orthologues. In contrast, orchid GLO-like genes form a single clade of ancient orthologues and recent paralogues. DEF-like genes from orchid clade 2 (OMADS3-like genes) are under less stringent purifying selection than the other orchid DEF-like and GLO-like genes. In comparison with orchids, purifying selection was less stringent in DEF

  8. The S locus-linked Primula homeotic mutant sepaloid shows characteristics of a B-function mutant but does not result from mutation in a B-function gene.

    PubMed

    Li, Jinhong; Webster, Margaret; Dudas, Brigitta; Cook, Holly; Manfield, Iain; Davies, Brendan; Gilmartin, Philip M

    2008-10-01

    Floral homeotic and flower development mutants of Primula, including double, Hose in Hose, Jack in the Green and Split Perianth, have been cultivated since the late 1500s as ornamental plants but until recently have attracted limited scientific attention. Here we describe the characterization of a new mutant phenotype, sepaloid, that produces flowers comprising only sepals and carpels. The sepaloid mutation is recessive, and is linked to the S locus that controls floral heteromorphy. The phenotype shows developmental variability, with flowers containing three whorls of sepals surrounding fertile carpels, two whorls of sepals with a diminished third whorl of sepals surrounding a fourth whorl of carpels, or three whorls of sepals surrounding abnormal carpels. In some respects, these phenotypes resemble the Arabidopsis and Antirrhinum homeotic B-function mutants apetala3/deficiens (ap3/def) and pistillata/globosa (pi/glo). We have isolated the Primula vulgaris B-function genes PvDEFICIENS (PvDEF) and PvGLOBOSA (PvGLO), expression of both of which is affected in the sepaloid mutant. PvGLO, like sepaloid, is linked to the S locus, whereas PvDEF is not. However, our analyses reveal that sepaloid and PvGLO represent different genes. We conclude that SEPALOID is an S-linked independent regulator of floral organ identity genes including PvDEF and PvGLO.

  9. The Arabidopsis floral homeotic proteins APETALA3 and PISTILLATA negatively regulate the BANQUO genes implicated in light signaling.

    PubMed

    Mara, Chloe D; Huang, Tengbo; Irish, Vivian F

    2010-03-01

    The Arabidopsis thaliana MADS box transcription factors APETALA3 (AP3) and PISTILLATA (PI) heterodimerize and are required to specify petal identity, yet many details of how this regulatory process is effected are unclear. We have identified three related genes, BHLH136/BANQUO1 (BNQ1), BHLH134/BANQUO2 (BNQ2), and BHLH161/BANQUO3 (BNQ3), as being directly and negatively regulated by AP3 and PI in petals. BNQ1, BNQ2, and BNQ3 encode products belonging to a family of atypical non-DNA binding basic helix-loop-helix (bHLH) proteins that heterodimerize with and negatively regulate bHLH transcription factors. We show that bnq3 mutants have pale-green sepals and carpels and decreased chlorophyll levels, suggesting that BNQ3 has a role in regulating light responses. The ap3 bnq3 double mutant displays pale second-whorl organs, supporting the hypothesis that BNQ3 is downstream of AP3. Consistent with a role in light response, we show that the BNQ gene products regulate the function of HFR1 (for LONG HYPOCOTYL IN FAR-RED1), which encodes a bHLH protein that regulates photomorphogenesis through modulating phytochrome and cryptochrome signaling. The BNQ genes also are required for appropriate regulation of flowering time. Our results suggest that petal identity is specified in part through downregulation of BNQ-dependent photomorphogenic and developmental signaling pathways.

  10. Comparative analysis of leg and antenna development in wild-type and homeotic Drosophila melanogaster.

    PubMed

    Cummins, Mark; Pueyo, Jose I; Greig, Steve A; Couso, Juan Pablo

    2003-07-01

    The insect leg and antenna are thought to be homologous structures, evolved from a common ancestral appendage. The homeotic transformations of antenna to leg in Drosophila produced by mutation of the Hox gene Antennapedia are position-specific, such that every particular antenna structure is transformed into a specific leg counterpart. This has been taken to suggest that the developmental programmes of these two appendages are still similar. In particular, the mechanisms for the specification of a cell's position within the appendage would be identical, only their interpretation would be different and subject to homeotic gene control. Here we explore the degree of conservation between the developmental programmes of leg and antenna in Drosophila and other dipterans, in wild-type and homeotic conditions. Most of the appendage pattern-forming genes are active in both appendages, and their expression domains are partially conserved. However, the regulatory relationships and interactions between these genes are different, and in fact cells change their expression while undergoing homeotic transformation. Thus, the positional information, and the mechanisms which generate it, are not strictly conserved between leg and antenna; and homeotic genes alter the establishment of positional clues, not only their interpretation. The partial conservation of pattern-forming genes in both appendages ensures a predictable re-specification of positional clues, producing the observed positional specificity of homeotic transformations.

  11. [Use of homeotic mutation tasselseed2 for investigation of the action of maize meiotic genes during micro- and megasporogenesis].

    PubMed

    Peremyslova, E E

    2006-04-01

    The manifestation of the ms43 maize meiotic mutation in the megasporogenesis of ts2 ms43 double mutants has been studied. Combined genetical and cytological analysis of the progeny of diheterozygote selfing showed that the ms43 mei gene was not microsporogenesis-specific. The manifestation of ms43 in megasporogenesis of the double mutants proved to be affected by the ts2 mutation. It prevented formation of the phenotype characteristic of ms43 and distorted early developmental stages of the entire ovule. It is the first study of megasporogenesis in tasselseed2 mutant tassels. Cytological data on the afd1 mutation in single and double mutants are presented. Possible mechanisms of the interaction between the ms43 and ts2 mutations are discussed.

  12. Homeotic MADS-box genes encoding LeMADS-MC orthologues in wild tomato species (genus Solanum).

    PubMed

    Slugina, M A; Kochieva, E Z; Skryabin, K G; Shchennikova, A V

    2017-05-01

    New full-length genes encoding the LeMADS-MC transcription factor orthologues were identified and functionally characterized in wild tomato species S. cheesmaniae and S. habrochaites. A comparative analysis of the encoded proteins and LeMADS-MC of the cultivated tomato species S. lycopersicum revealed two major amino acid residues substitutions: V155E in the K-domain of ShaMADS-MC (S. habrochaites) and S80L in the I-region of SchMADS-MC (S. cheesmaniae). Structural differences of the C-terminal regions of MC and the canonical euAP1 proteins indicate possible chromosomal rearrangements in the Solanoideae subfamily, which, however, did not change the main known conserved euAP1 functions.

  13. Homeotic and Embryonic Gene Expression in Breast Adipose Tissue and in Adipose Tissues Used as Donor Sites in Plastic Surgery.

    PubMed

    Foissac, Rémi; Villageois, Phi; Chignon-Sicard, Bérengère; Georgiou, Charalambos; Camuzard, Olivier; Dani, Christian

    2017-03-01

    Autologous fat grafting has become an essential procedure in breast reconstructive surgery. However, molecular knowledge of different adipose donor sites remains inadequate. Tissue regeneration studies have shown that it is essential to match the Hox code of transplanted cells and host tissues to achieve correct repair. This study aims to provide a better molecular understanding of adipose tissue. Over the course of 1 year, the authors prospectively included 15 patients and studied seven adipose areas: chin, breast, arm, abdomen, thigh, hip, and knee. The first step consisted of the surgical harvesting of adipose tissue. RNA was then extracted and converted into cDNA to study gene expression levels of 10 targeted genes by real-time polymerase chain reaction. Forty samples from Caucasian women with a mean age of 48 years were studied. The expression of PAX3, a marker of neuroectodermal origin, was significantly higher in the breast, with a decreasing gradient from the upper to lower areas of the body. An inverse gradient was found for the expression of HOXC10. This expression profile was statistically significant for the areas of the thigh and knee compared with the breast (p < 0.0083). Breast fat may have a specific embryologic origin compared with the knee and thigh. The reinjection of adipocytes from the infraumbilical area leads to the transfer of cells highly expressing HOXC10. This study raises questions about the safety of this procedure, and future studies will be required to examine molecular modifications of adipose cells transferred to a heterotopic location. Therapeutic, V.

  14. Variable motif utilization in homeotic selector (Hox)-cofactor complex formation controls specificity.

    PubMed

    Lelli, Katherine M; Noro, Barbara; Mann, Richard S

    2011-12-27

    Homeotic selector (Hox) proteins often bind DNA cooperatively with cofactors such as Extradenticle (Exd) and Homothorax (Hth) to achieve functional specificity in vivo. Previous studies identified the Hox YPWM motif as an important Exd interaction motif. Using a comparative approach, we characterize the contribution of this and additional conserved sequence motifs to the regulation of specific target genes for three Drosophila Hox proteins. We find that Sex combs reduced (Scr) uses a simple interaction mechanism, where a single tryptophan-containing motif is necessary for Exd-dependent DNA-binding and in vivo functions. Abdominal-A (AbdA) is more complex, using multiple conserved motifs in a context-dependent manner. Lastly, Ultrabithorax (Ubx) is the most flexible, in that it uses multiple conserved motifs that function in parallel to regulate target genes in vivo. We propose that using different binding mechanisms with the same cofactor may be one strategy to achieve functional specificity in vivo.

  15. Environmental sex reversal, Trojan sex genes, and sex ratio adjustment: conditions and population consequences.

    PubMed

    Stelkens, Rike B; Wedekind, Claus

    2010-02-01

    The great diversity of sex determination mechanisms in animals and plants ranges from genetic sex determination (GSD, e.g. mammals, birds, and most dioecious plants) to environmental sex determination (ESD, e.g. many reptiles) and includes a mixture of both, for example when an individual's genetically determined sex is environmentally reversed during ontogeny (ESR, environmental sex reversal, e.g. many fish and amphibia). ESD and ESR can lead to widely varying and unstable population sex ratios. Populations exposed to conditions such as endocrine-active substances or temperature shifts may decline over time due to skewed sex ratios, a scenario that may become increasingly relevant with greater anthropogenic interference on watercourses. Continuous exposure of populations to factors causing ESR could lead to the extinction of genetic sex factors and may render a population dependent on the environmental factors that induce the sex change. However, ESR also presents opportunities for population management, especially if the Y or W chromosome is not, or not severely, degenerated. This seems to be the case in many amphibians and fish. Population growth or decline in such species can potentially be controlled through the introduction of so-called Trojan sex genes carriers, individuals that possess sex chromosomes or genes opposite from what their phenotype predicts. Here, we review the conditions for ESR, its prevalence in natural populations, the resulting physiological and reproductive consequences, and how these may become instrumental for population management.

  16. The Arabidopsis floral meristem identity genes AP1, AGL24 and SVP directly repress class B and C floral homeotic genes.

    PubMed

    Gregis, Veronica; Sessa, Alice; Dorca-Fornell, Carmen; Kater, Martin M

    2009-11-01

    During the initial stages of flower development, floral meristems increase in size without the formation of floral organs. When a critical meristem size is reached, the floral meristem begins to develop the floral organs. The first stages of flower development are characterized by the expression of genes such as Apetala 1 (AP1), cauliflower (CAL), AGAMOUS-LIKE 24 (AGL24) and short vegetative phase (SVP). We have shown that AP1, AGL24 and SVP act redundantly to control the identity of the floral meristem and to repress expression of class B, C and E genes. Recently, it was shown that class E gene repression was direct and established by two independent pathways. We show here that repression of class B and C genes is also directly established by a co-repressor complex that comprises LEUNIG (LUG), SEUSS (SEU) and the MADS box dimers AP1-AGL24 and AP1-SVP. Furthermore, we show that the distantly related suppressor of overexpression of CO 1 (SOC1) MADS box gene can complement for the loss of AGL24 and SVP activity; however, under normal conditions, this transcription factor does not play a role during the early stages of flower development.

  17. Reverse homeosis in homeotically reconstructed ribbonworms

    PubMed Central

    Tarpin, Michel; Gehring, Walter J.; Bièrne, Jacques

    1999-01-01

    Homeosis is the replacement of one body part by another, which may be caused by either developmental or genetic variations. It is particularly obvious in segmented animals, like insects, in which one body segment may be transformed into another. However, homeosis also occurs in animals without overt segmentation that also have detailed positional information specifying their body plan. By grafting, we have artificially generated homeotic ribbonworms of the species Lineus ruber with a duplicated ocellar region replacing the postocellar region anterior to the brain. Such chimeric animals are capable of complete morphogenetic regulation of the anterior–posterior (A–P) pattern. The missing postocellar region is restored by intercalary regeneration, and the anterior duplicated ocellar region is eliminated by a process called transgeneration. Thus, homeosis is reversed, and a completely normal pattern along the A–P axis is restored. This reverse homeosis involves the elimination of the syngeneic eyes and the survival of the grafted allogeneic eye region. LsPax-6, the Lineus sanguineus ortholog of the mammalian Pax-6 gene, which is considered to be a master control gene for eye morphogenesis, is expressed specifically in regenerating, regenerated, and intact eye regions. Our data show that ribbonworm eyes are either maintained or they regress according to their position along the A–P axis, even though there are no obvious segmental boundaries. This system allows us to test the function of LsPax-6 protein not only during eye regeneration but also during maintenance and regression of the eyes. PMID:10518548

  18. Distribution of the Sex combs reduced Gene Products in Drosophila melanogaster

    PubMed Central

    Mahaffey, James W.; Kaufman, Thomas C.

    1987-01-01

    The spatial and temporal distribution of RNA and protein encoded by the homeotic Sex combs reduced (Scr) gene were examined during Drosophila development. The gene products are present in the epidermis of both the labial and first thoracic segments as would be predicted from prior genetic studies. However, the pattern in the central nervous system (CNS) and mesoderm is further restricted; the major expression located in the labial neuromere of the CNS and the mesoderm of the first thoracic segment. The spatial restriction within the CNS is correlated with and may be due to a differential timing of expression in the labial and first thoracic ectoderm. The labial ectoderm accumulates the Scr RNA prior to segregation of the neuroblasts while expression in the first thoracic ectoderm occurs after neuroblast segregation. The protein is also observed in the subesophageal ganglia of both larvae and adults, as well as in the labial and first thoracic imaginal discs. Surprisingly, the protein is also present to a lesser extent in second and third thoracic leg discs. PMID:3117618

  19. Homeotic functions of the Teashirt transcription factor during adult Drosophila development

    PubMed Central

    Wang, Wei; Tindell, Neil; Yan, Shun; Yoder, John H.

    2013-01-01

    Summary During Drosophila development region-specific regulation of target genes by Hox proteins is modulated by genetic interactions with various cofactors and genetic collaborators. During embryogenesis one such modulator of Hox target specificity is the zinc-finger transcription factor Teashirt (Tsh) that is expressed in the developing trunk and cooperatively functions with trunk-specific Hox proteins to promote appropriate segment fate. This embryonic function of Tsh is characterized as homeotic since loss of embryonic Tsh activity leads to transformation of trunk segments toward head identity. In addition to this embryonic homeotic role, Tsh also performs vital Hox-independent functions through patterning numerous embryonic, larval and adult structures. Here we address whether the homeotic function of Tsh is maintained throughout development by investigating its contribution to patterning the adult abdomen. We show that Tsh is expressed throughout the developing abdomen and that this expression is dependent on the three Bithorax Hox proteins Ultrabithorax, Abdominal-A and Abdominal-B. Conditional reduction of Tsh activity during pupation reveals broad homeotic roles for this transcription factor throughout the adult abdomen. Additionally we show that, as during embryogenesis, the tsh paralog tiptop (tio) plays a partially redundant role in this homeotic activity. PMID:23336073

  20. Homeotic functions of the Teashirt transcription factor during adult Drosophila development.

    PubMed

    Wang, Wei; Tindell, Neil; Yan, Shun; Yoder, John H

    2013-01-15

    During Drosophila development region-specific regulation of target genes by Hox proteins is modulated by genetic interactions with various cofactors and genetic collaborators. During embryogenesis one such modulator of Hox target specificity is the zinc-finger transcription factor Teashirt (Tsh) that is expressed in the developing trunk and cooperatively functions with trunk-specific Hox proteins to promote appropriate segment fate. This embryonic function of Tsh is characterized as homeotic since loss of embryonic Tsh activity leads to transformation of trunk segments toward head identity. In addition to this embryonic homeotic role, Tsh also performs vital Hox-independent functions through patterning numerous embryonic, larval and adult structures. Here we address whether the homeotic function of Tsh is maintained throughout development by investigating its contribution to patterning the adult abdomen. We show that Tsh is expressed throughout the developing abdomen and that this expression is dependent on the three Bithorax Hox proteins Ultrabithorax, Abdominal-A and Abdominal-B. Conditional reduction of Tsh activity during pupation reveals broad homeotic roles for this transcription factor throughout the adult abdomen. Additionally we show that, as during embryogenesis, the tsh paralog tiptop (tio) plays a partially redundant role in this homeotic activity.

  1. A deficiency of the homeotic complex of the beetle Tribolium

    NASA Technical Reports Server (NTRS)

    Stuart, J. J.; Brown, S. J.; Beeman, R. W.; Denell, R. E.; Spooner, B. S. (Principal Investigator)

    1991-01-01

    In Drosophila, the establishment of regional commitments along most of the anterior/posterior axis of the developing embryo depends on two clusters of homeotic genes: the Antennapedia complex (ANT-C) and the bithorax complex (BX-C). The red flour beetle has a single complex (HOM-C) representing the homologues of the ANT-C and BX-C in juxtaposition. Beetles trans-heterozygous for two particular HOM-C mutations spontaneously generate a large deficiency, presumably by an exchange within the common region of two overlapping inversions. Genetic and molecular results indicate that this deficiency spans at least the interval between the Deformed and abdominal-A homologues. In deficiency homozygous embryos, all gnathal, thoracic and abdominal segments develop antennal appendages, suggesting that a gene(s) has been deleted that acts to distinguish trunk from head. There is no evidence that beetles have a homologue of the segmentation gene fushi tarazu of similar genomic location and function. On the basis of the genetic tractability, convenient genome size and organization of Tribolium, and its relatively long phylogenetic divergence from Drosophila (>300 million years), we have integrated developmental genetic and molecular analyses of the HOM-C. We isolated about 70 mutations in the complex representing at least six complementation groups. The homeotic phenotypes of adults and lethal embryos lead us to believe that these beetle genes are homologous with the Drosophila genes indicated in Fig. 1 (see text).

  2. Pipsqueak and GAGA factor act in concert as partners at homeotic and many other loci

    PubMed Central

    Schwendemann, Alexander; Lehmann, Michael

    2002-01-01

    The Drosophila GAGA factor (GAF) controls transcription and other chromosome functions by altering chromatin structure. We found that a second GAGA-binding protein of Drosophila, Pipsqueak (Psq), can directly bind to GAF and is associated with GAF in vivo. Genetic interaction studies provide evidence that Psq and GAF act together in the transcriptional activation and silencing of homeotic genes. A complete colocalization of Psq and GAF on polytene interphase chromosomes and mitotic chromosomes suggests that the two proteins cooperate as general partners not only at homeotic loci, but also at hundreds of other chromosomal sites. PMID:12271134

  3. Polyandry and sex-specific gene expression.

    PubMed

    Mank, Judith E; Wedell, Nina; Hosken, David J

    2013-03-05

    Polyandry is widespread in nature, and has important evolutionary consequences for the evolution of sexual dimorphism and sexual conflict. Although many of the phenotypic consequences of polyandry have been elucidated, our understanding of the impacts of polyandry and mating systems on the genome is in its infancy. Polyandry can intensify selection on sexual characters and generate more intense sexual conflict. This has consequences for sequence evolution, but also for sex-biased gene expression, which acts as a link between mating systems, sex-specific selection and the evolution of sexual dimorphism. We discuss this and the remarkable confluence of sexual-conflict theory and patterns of gene expression, while also making predictions about transcription patterns, mating systems and sexual conflict. Gene expression is a key link in the genotype-phenotype chain, and although in its early stages, understanding the sexual selection-transcription relationship will provide significant insights into this critical association.

  4. Polyandry and sex-specific gene expression

    PubMed Central

    Mank, Judith E.; Wedell, Nina; Hosken, David J.

    2013-01-01

    Polyandry is widespread in nature, and has important evolutionary consequences for the evolution of sexual dimorphism and sexual conflict. Although many of the phenotypic consequences of polyandry have been elucidated, our understanding of the impacts of polyandry and mating systems on the genome is in its infancy. Polyandry can intensify selection on sexual characters and generate more intense sexual conflict. This has consequences for sequence evolution, but also for sex-biased gene expression, which acts as a link between mating systems, sex-specific selection and the evolution of sexual dimorphism. We discuss this and the remarkable confluence of sexual-conflict theory and patterns of gene expression, while also making predictions about transcription patterns, mating systems and sexual conflict. Gene expression is a key link in the genotype–phenotype chain, and although in its early stages, understanding the sexual selection–transcription relationship will provide significant insights into this critical association. PMID:23339238

  5. Homeotic Evolution in the Mammalia: Diversification of Therian Axial Seriation and the Morphogenetic Basis of Human Origins

    PubMed Central

    Filler, Aaron G.

    2007-01-01

    Background Despite the rising interest in homeotic genes, little has been known about the course and pattern of evolution of homeotic traits across the mammalian radiation. An array of emerging and diversifying homeotic gradients revealed by this study appear to generate new body plans and drive evolution at a large scale. Methodology/Principal Findings This study identifies and evaluates a set of homeotic gradients across 250 extant and fossil mammalian species and their antecedents over a period of 220 million years. These traits are generally expressed as co-linear gradients along the body axis rather than as distinct segmental identities. Relative position or occurrence sequence vary independently and are subject to polarity reversal and mirroring. Five major gradient modification sets are identified: (1)–quantitative changes of primary segmental identity pattern that appeared at the origin of the tetrapods ; (2)–frame shift relation of costal and vertebral identity which diversifies from the time of amniote origins; (3)–duplication, mirroring, splitting and diversification of the neomorphic laminar process first commencing at the dawn of mammals; (4)–emergence of homologically variable lumbar lateral processes upon commencement of the radiation of therian mammals and ; (5)–inflexions and transpositions of the relative position of the horizontal septum of the body and the neuraxis at the emergence of various orders of therian mammals. Convergent functional changes under homeotic control include laminar articular engagement with septo-neural transposition and ventrally arrayed lumbar transverse process support systems. Conclusion/Significance Clusters of homeotic transformations mark the emergence point of mammals in the Triassic and the radiation of therians in the Cretaceous. A cluster of homeotic changes in the Miocene hominoid Morotopithecus that are still seen in humans supports establishment of a new “hominiform” clade and suggests a homeotic

  6. Homeotic evolution in the mammalia: diversification of therian axial seriation and the morphogenetic basis of human origins.

    PubMed

    Filler, Aaron G

    2007-10-10

    Despite the rising interest in homeotic genes, little has been known about the course and pattern of evolution of homeotic traits across the mammalian radiation. An array of emerging and diversifying homeotic gradients revealed by this study appear to generate new body plans and drive evolution at a large scale. This study identifies and evaluates a set of homeotic gradients across 250 extant and fossil mammalian species and their antecedents over a period of 220 million years. These traits are generally expressed as co-linear gradients along the body axis rather than as distinct segmental identities. Relative position or occurrence sequence vary independently and are subject to polarity reversal and mirroring. Five major gradient modification sets are identified: (1)--quantitative changes of primary segmental identity pattern that appeared at the origin of the tetrapods ; (2)--frame shift relation of costal and vertebral identity which diversifies from the time of amniote origins; (3)--duplication, mirroring, splitting and diversification of the neomorphic laminar process first commencing at the dawn of mammals; (4)--emergence of homologically variable lumbar lateral processes upon commencement of the radiation of therian mammals and ; (5)--inflexions and transpositions of the relative position of the horizontal septum of the body and the neuraxis at the emergence of various orders of therian mammals. Convergent functional changes under homeotic control include laminar articular engagement with septo-neural transposition and ventrally arrayed lumbar transverse process support systems. Clusters of homeotic transformations mark the emergence point of mammals in the Triassic and the radiation of therians in the Cretaceous. A cluster of homeotic changes in the Miocene hominoid Morotopithecus that are still seen in humans supports establishment of a new "hominiform" clade and suggests a homeotic origin for the human upright body plan.

  7. Sex chromosomes and sex-determining genes: insights from marsupials and monotremes.

    PubMed

    Pask, A; Graves, J A

    1999-06-01

    Comparative studies of the genes involved in sex determination in the three extant classes of mammals, and other vertebrates, has allowed us to identify genes that are highly conserved in vertebrate sex determination and those that have recently evolved roles in one lineage. Analysis of the conservation and function of candidate genes in different vertebrate groups has been crucial to our understanding of their function and positioning in a conserved vertebrate sex-determining pathway. Here we review comparisons between genes in the sex-determining pathway in different vertebrates, and ask how these comparisons affect our views on the role of each gene in vertebrate sex determination.

  8. [Maintenance of the patterns of expression of homeotic genes in the development of Drosophila melanogaster by proteins of the polycomb, trithorax, and ETP groups].

    PubMed

    Fedorova, E V; Pindiurin, A V; Baricheva, E M

    2009-10-01

    Proteins encoded by genes of the groups Polycomb (PcG), trithorax (trxG), and the Enhancer of Trithorax and Polycomb Group (ETP) are important regulators of expression of most developmental genes. Data concerning all currently described genes assigned to these groups are summarized in the review. Genetic interactions of these genes and phenotypical manifestation of their mutations are described. Data on the PcG, trxG, and ETP proteins are systemized. Questions are considered concerning the formation of multimeric complexes containing proteins of these groups, recruitment of these complexes to regulatory elements of target genes, and the mechanisms of activation/repression of gene expression.

  9. Reconstitution of 'floral quartets' in vitro involving class B and class E floral homeotic proteins.

    PubMed

    Melzer, Rainer; Theissen, Günter

    2009-05-01

    Homeotic MADS box genes encoding transcription factors specify the identity of floral organs by interacting in a combinatorial way. The 'floral quartet model', published several years ago, pulled together several lines of evidence suggesting that floral homeotic proteins bind as tetramers to two separated DNA sequence elements termed 'CArG boxes' by looping the intervening DNA. However, experimental support for 'floral quartet' formation remains scarce. Recently, we have shown that the class E floral homeotic protein SEPALLATA3 (SEP3) is sufficient to loop DNA in floral-quartet-like complexes in vitro. Here, we demonstrate that the class B floral homeotic proteins APETALA3 (AP3) and PISTILLATA (PI) do only weakly, at best, form floral-quartet-like structures on their own. However, they can be incorporated into such complexes together with SEP3. The subdomain K3 of SEP3 is of critical importance for the DNA-bound heterotetramers to be formed and is capable to mediate floral quartet formation even in the sequence context of AP3 and PI. Evidence is presented suggesting that complexes composed of SEP3, AP3 and PI form preferentially over other possible complexes. Based on these findings we propose a mechanism of how target gene specificity might be achieved at the level of floral quartet stability.

  10. Homeotic shift at the dawn of the turtle evolution

    NASA Astrophysics Data System (ADS)

    Szczygielski, Tomasz

    2017-04-01

    All derived turtles are characterized by one of the strongest reductions of the dorsal elements among Amniota, and have only 10 dorsal and eight cervical vertebrae. I demonstrate that the Late Triassic turtles, which represent successive stages of the shell evolution, indicate that the shift of the boundary between the cervical and dorsal sections of the vertebral column occurred over the course of several million years after the formation of complete carapace. The more generalized reptilian formula of at most seven cervicals and at least 11 dorsals is thus plesiomorphic for Testudinata. The morphological modifications associated with an anterior homeotic change of the first dorsal vertebra towards the last cervical vertebra in the Triassic turtles are partially recapitulated by the reduction of the first dorsal vertebra in crown-group Testudines, and they resemble the morphologies observed under laboratory conditions resulting from the experimental changes of Hox gene expression patterns. This homeotic shift hypothesis is supported by the, unique to turtles, restriction of Hox-5 expression domains, somitic precursors of scapula, and brachial plexus branches to the cervical region, by the number of the marginal scute-forming placodes, which was larger in the Triassic than in modern turtles, and by phylogenetic analyses.

  11. Homeotic shift at the dawn of the turtle evolution

    PubMed Central

    2017-01-01

    All derived turtles are characterized by one of the strongest reductions of the dorsal elements among Amniota, and have only 10 dorsal and eight cervical vertebrae. I demonstrate that the Late Triassic turtles, which represent successive stages of the shell evolution, indicate that the shift of the boundary between the cervical and dorsal sections of the vertebral column occurred over the course of several million years after the formation of complete carapace. The more generalized reptilian formula of at most seven cervicals and at least 11 dorsals is thus plesiomorphic for Testudinata. The morphological modifications associated with an anterior homeotic change of the first dorsal vertebra towards the last cervical vertebra in the Triassic turtles are partially recapitulated by the reduction of the first dorsal vertebra in crown-group Testudines, and they resemble the morphologies observed under laboratory conditions resulting from the experimental changes of Hox gene expression patterns. This homeotic shift hypothesis is supported by the, unique to turtles, restriction of Hox-5 expression domains, somitic precursors of scapula, and brachial plexus branches to the cervical region, by the number of the marginal scute-forming placodes, which was larger in the Triassic than in modern turtles, and by phylogenetic analyses. PMID:28484613

  12. Sex change strategy and the aromatase genes.

    PubMed

    Gardner, L; Anderson, T; Place, A R; Dixon, B; Elizur, A

    2005-04-01

    Sequential hermaphroditism is a common reproductive strategy in many teleosts. Steroid production is known to mediate both the natural and induced sex change, yet beyond this the physiology directing this process has received little attention. Cytochrome P450 aromatase is a key enzyme in the hormonal pathway catalysing the conversion of sex steroids, androgens to oestrogens, and thus is highly relevant to the process of sex change. This study reports the isolation of cDNA sequences for aromatase isoforms CYP19A1 and CYP19A2 from teleost species representing three forms of sexual hermaphroditism: Lates calcarifer (protandry), Cromileptes altivelis (protogyny), and Gobiodon histrio (bi-directional). Deduced amino acid analysis of these isoforms with other reported isoforms from gonochoristic (single sex) teleosts revealed 56-95% identity within the same isoform while only 48-65% identity between isoforms irrespective of species and sexual strategy. Phylogenetic analysis supported this result separating sequences into isoform exclusive clades in spite of species apparent evolutionary distance. Furthermore, this study isolates 5' flanking regions of all above genes and describes putative cis-acting elements therein. Elements identified include steroidogenic factor 1 binding site (SF-1), oestrogen response element (ERE), progesterone response element (PRE), androgen response element (ARE), glucocorticoid response elements (GRE), peroxisome proliferator-activated receptor alpha/retinoid X receptor alpha heterodimer responsive element (PPARalpha/RXRalpha), nuclear factor kappabeta (NF-kappabeta), SOX 5, SOX 9, and Wilms tumor suppressor (WTI). A hypothetical in vivo model was constructed for both isoforms highlighting potential roles of these putative cis-acting elements with reference to normal function and sexual hermaphroditism.

  13. [Elucidation of key genes in sex determination in genetics teaching].

    PubMed

    Li, Meng; He, Zhumei

    2014-06-01

    Sex is an important and complex feature of organisms, which is controlled by the genetic and environmental factors. The genetic factors, i.e., genes, are vital in sex determination. However, not all the related genes play the same roles, and some key genes play a vital role in the sex determination and differentiation. With the development of the modern genetics, a great progress on the key genes has been made in sex determination. In this review, we summarize the mechanism of sex determination and the strategy of how to study the key genes in sex determination. It will help us to understand the mechanism of sex determination better in the teaching of genetics.

  14. Isolation and phylogenetic footprinting analysis of the 5'-regulatory region of the floral homeotic gene OrcPI from Orchis italica (Orchidaceae).

    PubMed

    Aceto, Serena; Cantone, Carmela; Chiaiese, Pasquale; Ruotolo, Gianluca; Sica, Maria; Gaudio, Luciano

    2010-01-01

    The nucleotide sequences of regulatory elements from homologous genes can be strongly divergent. Phylogenetic footprinting, a comparative analysis of noncoding regions, can detect putative transcription factor binding sites (TFBSs) shared among the regulatory regions of 2 or more homologous genes. These conserved motifs have the potential to serve the same regulatory function in distantly related taxa. We isolated the 5'-noncoding region of the OrcPI gene, a MADS-box transcription factor involved in flower development in Orchis italica, using the thermal asymmetric interlaced polymerase chain reaction technique. This region (comprising 1352 bp) induced transient beta-glucuronidase expression in the petal tissue of white Rosa hybrida flowers and represents the 5'-regulatory sequence of the OrcPI gene. Phylogenetic footprinting analysis detected conserved regions within the 5'-regulatory sequence of OrcPI and the homologous regions of Oryza sativa, Lilium regale, and Arabidopsis thaliana. Some of these sequences are known TFBSs described in databases of plant regulatory elements. Nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under the following accession numbers: AF198055 promoter region of the PISTILLATA (PI) gene of A. thaliana; AB094985 cDNA of OrcPI (PI/GLOBOSA [PI/GLO] homologue) of O. italica; AB378089 5'-regulatory region of the OrcPI gene of O. italica; AP008211 putative promoter region of OSMADS2 (PI/GLO homologue) of O. sativa; AP008207 putative promoter region of OSMADS4 (PI/GLO homologue) of O. sativa; and AB158292 putative promoter region of the PI/GLO homologue of L. regale.

  15. Sex-biased gene expression at homomorphic sex chromosomes in emus and its implication for sex chromosome evolution.

    PubMed

    Vicoso, Beatriz; Kaiser, Vera B; Bachtrog, Doris

    2013-04-16

    Sex chromosomes originate from autosomes. The accumulation of sexually antagonistic mutations on protosex chromosomes selects for a loss of recombination and sets in motion the evolutionary processes generating heteromorphic sex chromosomes. Recombination suppression and differentiation are generally viewed as the default path of sex chromosome evolution, and the occurrence of old, homomorphic sex chromosomes, such as those of ratite birds, has remained a mystery. Here, we analyze the genome and transcriptome of emu (Dromaius novaehollandiae) and confirm that most genes on the sex chromosome are shared between the Z and W. Surprisingly, however, levels of gene expression are generally sex-biased for all sex-linked genes relative to autosomes, including those in the pseudoautosomal region, and the male-bias increases after gonad formation. This expression bias suggests that the emu sex chromosomes have become masculinized, even in the absence of ZW differentiation. Thus, birds may have taken different evolutionary solutions to minimize the deleterious effects imposed by sexually antagonistic mutations: some lineages eliminate recombination along the protosex chromosomes to physically restrict sexually antagonistic alleles to one sex, whereas ratites evolved sex-biased expression to confine the product of a sexually antagonistic allele to the sex it benefits. This difference in conflict resolution may explain the preservation of recombining, homomorphic sex chromosomes in other lineages and illustrates the importance of sexually antagonistic mutations driving the evolution of sex chromosomes.

  16. Floral glycerolipid profiles in homeotic mutants of Arabidopsis thaliana.

    PubMed

    Nakamura, Yuki; Liu, Yu-Chi; Lin, Ying-Chen

    2014-08-08

    Flowers have distinct glycerolipid composition, yet its floral organ-specific profile remains elusive in Arabidopsis whose flowers are too tiny to dissect different floral organs. Here, we employed known floral homeotic mutants agamous-1 (ag-1) and apetala3-3 (ap3-3) to facilitate sample preparation enriched in different floral organs. The result of analysis on different polar glycerolipid classes and their fatty acid composition demonstrated that flowers of ap3-3 and ag-1 have distinct glycerolipid composition from that of wild type. Moreover, distinct set of glycerolipid biosynthetic genes is expressed in these mutants by qRT-PCR gene expression analysis. These data suggest that glycerolipid profile is distinct among different floral organs of Arabidopsis thaliana. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Absent, small or homeotic 2-like protein (ASH2L) enhances the transcription of the estrogen receptor α gene through GATA-binding protein 3 (GATA3).

    PubMed

    Qi, Jin; Huo, Lei; Zhu, Yiwei Tony; Zhu, Yi-Jun

    2014-11-07

    ASH2L is a component of MLL complexes that confer H3K4 trimethylation. The ASH2L gene is located at 8q11-12, which is often amplified in breast cancers. We found that increased ASH2L expression, which can result from gene amplification, is often correlated with increased ERα expression in both breast cancer cell lines and primary breast cancers. Forced expression of ASH2L induced ERα expression in mammary epithelial cells, whereas depletion of ASH2L suppressed ERα expression in breast cancer cells. To understand the mechanism by which ASH2L regulates ERα expression, we identified GATA3 as the binding protein of ASH2L. ASH2L was shown to potentiate the transcriptional activity of GATA3. ASH2L was recruited to the enhancer of the ERα gene through GATA3 to promote ERα transcription. This study established that ASH2L enhances ERα expression as a coactivator of GATA3 in breast cancers. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  18. Sex chromosomes and sex-determining genes: insights from marsupials and monotremes.

    PubMed

    Pask, A; Graves, J A

    2001-01-01

    Comparative studies of the genes involved in sex determination in the three extant classes of mammals, and other vertebrates, has allowed us to identify genes that are highly conserved in vertebrate sex determination and those that have recently evolved roles in one lineage. Analysis of the conservation and function of candidate sex determining genes in marsupials and monotremes has been crucial to our understanding of their function and positioning in a conserved mammalian sex-determining pathway, as well as their evolution. Here we review comparisons between genes in the sex-determining pathway in different vertebrates, and ask how these comparisons affect our views on the role of each gene in vertebrate sex determination.

  19. CRISPR/Cas9 mediated knockout of the abdominal-A homeotic gene in the global pest, diamondback moth (Plutella xylostella).

    PubMed

    Huang, Yuping; Chen, Yazhou; Zeng, Baosheng; Wang, Yajun; James, Anthony A; Gurr, Geoff M; Yang, Guang; Lin, Xijian; Huang, Yongping; You, Minsheng

    2016-08-01

    The diamondback moth, Plutella xylostella (L.), is a worldwide agricultural pest that has developed resistance to multiple classes of insecticides. Genetics-based approaches show promise as alternative pest management approaches but require functional studies to identify suitable gene targets. Here we use the CRISPR/Cas9 system to target a gene, abdominal-A, which has an important role in determining the identity and functionality of abdominal segments. We report that P. xylostella abdominal-A (Pxabd-A) has two structurally-similar splice isoforms (A and B) that differ only in the length of exon II, with 15 additional nucleotides in isoform A. Pxabd-A transcripts were detected in all developmental stages, and particularly in pupae and adults. CRISPR/Cas9-based mutagenesis of Pxabd-A exon I produced 91% chimeric mutants following injection of 448 eggs. Phenotypes with abnormal prolegs and malformed segments were visible in hatched larvae and unhatched embryos, and various defects were inherited by the next generation (G1). Genotyping of mutants demonstrated several mutations at the Pxabd-A genomic locus. The results indicate that a series of insertions and deletions were induced in the Pxabd-A locus, not only in G0 survivors but also in G1 individuals, and this provides a foundation for genome editing. Our study demonstrates the utility of the CRISPR/Cas9 system for targeting genes in an agricultural pest and therefore provides a foundation the development of novel pest management tools. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Sex-Specific Selection and Sex-Biased Gene Expression in Humans and Flies

    PubMed Central

    Kirkpatrick, Mark

    2016-01-01

    Sexual dimorphism results from sex-biased gene expression, which evolves when selection acts differently on males and females. While there is an intimate connection between sex-biased gene expression and sex-specific selection, few empirical studies have studied this relationship directly. Here we compare the two on a genome-wide scale in humans and flies. We find a distinctive “Twin Peaks” pattern in humans that relates the strength of sex-specific selection, quantified by genetic divergence between male and female adults at autosomal loci, to the degree of sex-biased expression. Genes with intermediate degrees of sex-biased expression show evidence of ongoing sex-specific selection, while genes with either little or completely sex-biased expression do not. This pattern apparently results from differential viability selection in males and females acting in the current generation. The Twin Peaks pattern is also found in Drosophila using a different measure of sex-specific selection acting on fertility. We develop a simple model that successfully recapitulates the Twin Peaks. Our results suggest that many genes with intermediate sex-biased expression experience ongoing sex-specific selection in humans and flies. PMID:27658217

  1. Sex-Specific Selection and Sex-Biased Gene Expression in Humans and Flies.

    PubMed

    Cheng, Changde; Kirkpatrick, Mark

    2016-09-01

    Sexual dimorphism results from sex-biased gene expression, which evolves when selection acts differently on males and females. While there is an intimate connection between sex-biased gene expression and sex-specific selection, few empirical studies have studied this relationship directly. Here we compare the two on a genome-wide scale in humans and flies. We find a distinctive "Twin Peaks" pattern in humans that relates the strength of sex-specific selection, quantified by genetic divergence between male and female adults at autosomal loci, to the degree of sex-biased expression. Genes with intermediate degrees of sex-biased expression show evidence of ongoing sex-specific selection, while genes with either little or completely sex-biased expression do not. This pattern apparently results from differential viability selection in males and females acting in the current generation. The Twin Peaks pattern is also found in Drosophila using a different measure of sex-specific selection acting on fertility. We develop a simple model that successfully recapitulates the Twin Peaks. Our results suggest that many genes with intermediate sex-biased expression experience ongoing sex-specific selection in humans and flies.

  2. Sex determining genes and sexual differentiation in a marsupial.

    PubMed

    Pask, A; Renfree, M B

    2001-11-01

    The role of genes in the differentiation of the testis and ovary has been extensively studied in the human and the mouse. Despite over a decade of investigations, the precise roles of genes and their interactions in the pathway of sex determination are still unclear. We have chosen to take a comparative look at sex determination and differentiation to gain insights into the evolution and the conserved functions of these genes. To achieve this, we have examined a wide variety of eutherian sex determining genes in a marsupial, the tammar wallaby, to determine which genes have a conserved and fundamental mammalian sex determining role. These investigations have provided many unique insights. Here, we review the recent molecular and endocrine investigations into sexual development in marsupials, and highlight how these studies have shed light on the roles of genes and hormones in mammalian sex determination and differentiation.

  3. The Drosophila microRNA iab-4 causes a dominant homeotic transformation of halteres to wings

    PubMed Central

    Ronshaugen, Matthew; Biemar, Frédéric; Piel, Jessica; Levine, Mike; Lai, Eric C.

    2005-01-01

    The Drosophila Bithorax Complex encodes three well-characterized homeodomain proteins that direct segment identity, as well as several noncoding RNAs of unknown function. Here, we analyze the iab-4 locus, which produces the microRNAs iab-4-5p and iab-4-3p. iab-4 is analogous to miR-196 in vertebrate Hox clusters. Previous studies demonstrate that miR-196 interacts with the Hoxb8 3′ untranslated region. Evidence is presented that miR-iab-4-5p directly inhibits Ubx activity in vivo. Ectopic expression of mir-iab-4-5p attenuates endogenous Ubx protein accumulation and induces a classical homeotic mutant phenotype: the transformation of halteres into wings. These findings provide the first evidence for a noncoding homeotic gene and raise the possibility that other such genes occur within the Bithorax complex. We also discuss the regulation of mir-iab-4 expression during development. PMID:16357215

  4. The Drosophila Homeotic Mutation Nasobemia (Antp(ns)) and Its Revertants: An Analysis of Mutational Reversion

    PubMed Central

    Talbert, P. B.; Garber, R. L.

    1994-01-01

    The homeotic gene Antennapedia (Antp) controls determination of many different cell types in the thorax and abdomen of Drosophila melanogaster. The spontaneous mutant allele Nasobemia (Antp(Ns)) and its revertants have been widely used to infer normal Antp gene function but have not themselves been thoroughly characterized. Our analysis reveals that Antp(Ns) consists of an internal 25-kb partial duplication of the Antp gene as well as a complex insertion of >40 kb of new DNA including two roo transposons. The duplication gives the mutant gene three Antp promoters, and transcripts from each of these are correctly processed to yield functional ANTP proteins. At least two of the promoters are ectopically active in the eye-antenna imaginal discs, leading to homeotic transformation of the adult head. A molecular and genetic description of several Antp(Ns) revertants shows them to be diverse in structure and activity, including a restoration of the wild type, rearrangements separating two of the Antp(Ns) promoters from the coding sequences, and protein nulls and hypomorphs affecting expression from all three of the promoters. Finally, one revertant has a suppressing lesion in the osa locus far away from Antp. These features explain the unusual homozygous viable nature of Antp(Ns), suggest a mechanism by which its homeotic transformation occurs, and exemplify the diversity of ways in which mutational reversion can take place. PMID:7851768

  5. Sex-Biased Gene Expression and Sexual Conflict throughout Development

    PubMed Central

    Ingleby, Fiona C.; Flis, Ilona; Morrow, Edward H.

    2015-01-01

    Sex-biased gene expression is likely to account for most sexually dimorphic traits because males and females share much of their genome. When fitness optima differ between sexes for a shared trait, sexual dimorphism can allow each sex to express their optimum trait phenotype, and in this way, the evolution of sex-biased gene expression is one mechanism that could help to resolve intralocus sexual conflict. Genome-wide patterns of sex-biased gene expression have been identified in a number of studies, which we review here. However, very little is known about how sex-biased gene expression relates to sex-specific fitness and about how sex-biased gene expression and conflict vary throughout development or across different genotypes, populations, and environments. We discuss the importance of these neglected areas of research and use data from a small-scale experiment on sex-specific expression of genes throughout development to highlight potentially interesting avenues for future research. PMID:25376837

  6. Sex-specific gene expression in the BXD mouse liver.

    PubMed

    Gatti, Daniel M; Zhao, Ni; Chesler, Elissa J; Bradford, Blair U; Shabalin, Andrey A; Yordanova, Roumyana; Lu, Lu; Rusyn, Ivan

    2010-08-01

    Differences in clinical phenotypes between the sexes are well documented and have their roots in differential gene expression. While sex has a major effect on gene expression, transcription is also influenced by complex interactions between individual genetic variation and environmental stimuli. In this study, we sought to understand how genetic variation affects sex-related differences in liver gene expression by performing genetic mapping of genomewide liver mRNA expression data in a genetically defined population of naive male and female mice from C57BL/6J, DBA/2J, B6D2F1, and 37 C57BL/6J x DBA/2J (BXD) recombinant inbred strains. As expected, we found that many genes important to xenobiotic metabolism and other important pathways exhibit sexually dimorphic expression. We also performed gene expression quantitative trait locus mapping in this panel and report that the most significant loci that appear to regulate a larger number of genes than expected by chance are largely sex independent. Importantly, we found that the degree of correlation within gene expression networks differs substantially between the sexes. Finally, we compare our results to a recently released human liver gene expression data set and report on important similarities in sexually dimorphic liver gene expression between mouse and human. This study enhances our understanding of sex differences at the genome level and between species, as well as increasing our knowledge of the molecular underpinnings of sex differences in responses to xenobiotics.

  7. A conserved microRNA module exerts homeotic control over Petunia hybrida and Antirrhinum majus floral organ identity.

    PubMed

    Cartolano, Maria; Castillo, Rosa; Efremova, Nadia; Kuckenberg, Markus; Zethof, Jan; Gerats, Tom; Schwarz-Sommer, Zsuzsanna; Vandenbussche, Michiel

    2007-07-01

    It is commonly thought that deep phylogenetic conservation of plant microRNAs (miRNAs) and their targets indicates conserved regulatory functions. We show that the blind (bl) mutant of Petunia hybrida and the fistulata (fis) mutant of Antirrhinum majus, which have similar homeotic phenotypes, are recessive alleles of two homologous miRNA-encoding genes. The BL and FIS genes control the spatial restriction of homeotic class C genes to the inner floral whorls, but their ubiquitous early floral expression patterns are in contradiction with a potential role in patterning C gene expression. We provide genetic evidence for the unexpected function of the MIRFIS and MIRBL genes in the center of the flower and propose a dynamic mechanism underlying their regulatory role. Notably, Arabidopsis thaliana, a more distantly related species, also contains this miRNA module but does not seem to use it to confine early C gene expression to the center of the flower.

  8. Vertebrate sex-determining genes play musical chairs.

    PubMed

    Pan, Qiaowei; Anderson, Jennifer; Bertho, Sylvain; Herpin, Amaury; Wilson, Catherine; Postlethwait, John H; Schartl, Manfred; Guiguen, Yann

    2016-01-01

    Sexual reproduction is one of the most highly conserved processes in evolution. However, the genetic and cellular mechanisms making the decision of whether the undifferentiated gonad of animal embryos develops either towards male or female are manifold and quite diverse. In vertebrates, sex-determining mechanisms range from environmental to simple or complex genetic mechanisms and different mechanisms have evolved repeatedly and independently. In species with simple genetic sex-determination, master sex-determining genes lying on sex chromosomes drive the gonadal differentiation process by switching on a developmental program, which ultimately leads to testicular or ovarian differentiation. So far, very few sex-determining genes have been identified in vertebrates and apart from mammals and birds, these genes are apparently not conserved over a larger number of related orders, families, genera, or even species. To fill this knowledge gap and to better explore genetic sex-determination, we propose a strategy (RAD-Sex) that makes use of next-generation sequencing technology to identify genetic markers that define sex-specific segments of the male or female genome.

  9. Vertebrate sex-determining genes play musical chairs

    PubMed Central

    Pan, Qiaowei; Anderson, Jennifer; Bertho, Sylvain; Herpin, Amaury; Wilson, Catherine; Postlethwait, John H.; Schartl, Manfred; Guiguen, Yann

    2017-01-01

    Sexual reproduction is one of the most highly conserved processes in evolution. However, the genetic and cellular mechanisms making the decision of whether the undifferentiated gonad of animal embryos develops either towards male or female are manifold and quite diverse. In vertebrates, sex-determining mechanisms range from environmental to simple or complex genetic mechanisms and different mechanisms have evolved repeatedly and independently. In species with simple genetic sex-determination, master sex-determining genes lying on sex chromosomes drive the gonadal differentiation process by switching on a developmental program, which ultimately leads to testicular or ovarian differentiation. So far, very few sex-determining genes have been identified in vertebrates and apart from mammals and birds, these genes are apparently not conserved over a larger number of related orders, families, genera, or even species. To fill this knowledge gap and to better explore genetic sex-determination, we propose a strategy (RAD-Sex) that makes use of next-generation sequencing technology to identify genetic markers that define sex-specific segments of the male or female genome. PMID:27291506

  10. Sex-related genes, directional sexual selection, and speciation.

    PubMed

    Civetta, A; Singh, R S

    1998-07-01

    Reproductive isolation and speciation can result from the establishment of either premating or postmating barriers that restrict gene flow between populations. Recent studies of speciation have been dominated by a molecular approach to dissect the genetic basis of hybrid male sterility, a specific form of postmating reproductive isolation. However, relatively little attention has been paid to the evolution of genes involved in premating isolation and genes generally involved in other sex-related functions (e.g., mating behavior, fertilization, spermatogenesis, sex determination). We have assembled DNA sequences from 51 nuclear genes and classified them based on their functional characteristics. The proportion of nonsynonymous to synonymous nucleotide substitutions were compared between Drosophila melanogaster, Drosophila simulans, and Drosophila pseudoobscura, as well as between Caenorhabditis elegans and Caenorhabditis briggsae. We found a high ratio of nonsynonymous to synonymous substitutions for sex-related genes (i.e., genes involved in mating behavior, fertilization, spermatogenesis, or sex determination). The results suggest that directional sexual selection has shaped the evolution of sex-related genes and that these changes have more likely occurred during the early stages of speciation. It is possible that directional selection becomes relaxed after reproductive isolation has been completed between more distantly related species (e.g., D. melanogaster and D. pseudoobscura). However, a saturation in the number of nucleotide substitutions since the time of species separation may mask any sign of directional selection between more distantly related species.

  11. Population and sex differences in Drosophila melanogaster brain gene expression.

    PubMed

    Catalán, Ana; Hutter, Stephan; Parsch, John

    2012-11-21

    Changes in gene regulation are thought to be crucial for the adaptation of organisms to their environment. Transcriptome analyses can be used to identify candidate genes for ecological adaptation, but can be complicated by variation in gene expression between tissues, sexes, or individuals. Here we use high-throughput RNA sequencing of a single Drosophila melanogaster tissue to detect brain-specific differences in gene expression between the sexes and between two populations, one from the ancestral species range in sub-Saharan Africa and one from the recently colonized species range in Europe. Relatively few genes (<100) displayed sexually dimorphic expression in the brain, but there was an enrichment of sex-biased genes, especially male-biased genes, on the X chromosome. Over 340 genes differed in brain expression between flies from the African and European populations, with the inter-population divergence being highly correlated between males and females. The differentially expressed genes included those involved in stress response, olfaction, and detoxification. Expression differences were associated with transposable element insertions at two genes implicated in insecticide resistance (Cyp6g1 and CHKov1). Analysis of the brain transcriptome revealed many genes differing in expression between populations that were not detected in previous studies using whole flies. There was little evidence for sex-specific regulatory adaptation in the brain, as most expression differences between populations were observed in both males and females. The enrichment of genes with sexually dimorphic expression on the X chromosome is consistent with dosage compensation mechanisms affecting sex-biased expression in somatic tissues.

  12. Population and sex differences in Drosophila melanogaster brain gene expression

    PubMed Central

    2012-01-01

    Background Changes in gene regulation are thought to be crucial for the adaptation of organisms to their environment. Transcriptome analyses can be used to identify candidate genes for ecological adaptation, but can be complicated by variation in gene expression between tissues, sexes, or individuals. Here we use high-throughput RNA sequencing of a single Drosophila melanogaster tissue to detect brain-specific differences in gene expression between the sexes and between two populations, one from the ancestral species range in sub-Saharan Africa and one from the recently colonized species range in Europe. Results Relatively few genes (<100) displayed sexually dimorphic expression in the brain, but there was an enrichment of sex-biased genes, especially male-biased genes, on the X chromosome. Over 340 genes differed in brain expression between flies from the African and European populations, with the inter-population divergence being highly correlated between males and females. The differentially expressed genes included those involved in stress response, olfaction, and detoxification. Expression differences were associated with transposable element insertions at two genes implicated in insecticide resistance (Cyp6g1 and CHKov1). Conclusions Analysis of the brain transcriptome revealed many genes differing in expression between populations that were not detected in previous studies using whole flies. There was little evidence for sex-specific regulatory adaptation in the brain, as most expression differences between populations were observed in both males and females. The enrichment of genes with sexually dimorphic expression on the X chromosome is consistent with dosage compensation mechanisms affecting sex-biased expression in somatic tissues. PMID:23170910

  13. Sex-linked genes and linkage maps in amphibians.

    PubMed

    Sumida, M; Nishioka1, M

    2000-06-01

    This paper reviews sex-linked genes and linkage maps in amphibians. It appears that there is no common ancestral or conserved sex-linkage group in amphibians, whereas an important proportion of other linkage groups has been conserved in amphibians. Comparisons of amphibian linkage maps with those of fishes and mammals reveal several syntenic associations apparently conserved over a very long period of vertebrate divergence.

  14. Identification of the sex genes in an early diverged fungus.

    PubMed

    Idnurm, Alexander; Walton, Felicia J; Floyd, Anna; Heitman, Joseph

    2008-01-10

    Sex determination in fungi is controlled by a small, specialized region of the genome in contrast to the large sex-specific chromosomes of animals and some plants. Different gene combinations reside at these mating-type (MAT) loci and confer sexual identity; invariably they encode homeodomain, alpha-box, or high mobility group (HMG)-domain transcription factors. So far, MAT loci have been characterized from a single monophyletic clade of fungi, the Dikarya (the ascomycetes and basidiomycetes), and the ancestral state and evolutionary history of these loci have remained a mystery. Mating in the basal members of the kingdom has been less well studied, and even their precise taxonomic inter-relationships are still obscure. Here we apply bioinformatic and genetic mapping to identify the sex-determining (sex) region in Phycomyces blakesleeanus (Zygomycota), which represents an early branch within the fungi. Each sex allele contains a single gene that encodes an HMG-domain protein, implicating the HMG-domain proteins as an earlier form of fungal MAT loci. Additionally, one allele also contains a copy of a unique, chromosome-specific repetitive element, suggesting a generalized mechanism for the earliest steps in the evolution of sex determination and sex chromosome structure in eukaryotes.

  15. Sex-specific embryonic gene expression in species with newly evolved sex chromosomes.

    PubMed

    Lott, Susan E; Villalta, Jacqueline E; Zhou, Qi; Bachtrog, Doris; Eisen, Michael B

    2014-02-01

    Sex chromosome dosage differences between females and males are a significant form of natural genetic variation in many species. Like many species with chromosomal sex determination, Drosophila females have two X chromosomes, while males have one X and one Y. Fusions of sex chromosomes with autosomes have occurred along the lineage leading to D. pseudoobscura and D. miranda. The resulting neo-sex chromosomes are gradually evolving the properties of sex chromosomes, and neo-X chromosomes are becoming targets for the molecular mechanisms that compensate for differences in X chromosome dose between sexes. We have previously shown that D. melanogaster possess at least two dosage compensation mechanisms: the well- characterized MSL-mediated dosage compensation active in most somatic tissues, and another system active during early embryogenesis prior to the onset of MSL-mediated dosage compensation. To better understand the developmental constraints on sex chromosome gene expression and evolution, we sequenced mRNA from individual male and female embryos of D. pseudoobscura and D. miranda, from ∼0.5 to 8 hours of development. Autosomal expression levels are highly conserved between these species. But, unlike D. melanogaster, we observe a general lack of dosage compensation in D. pseudoobscura and D. miranda prior to the onset of MSL-mediated dosage compensation. Thus, either there has been a lineage-specific gain or loss in early dosage compensation mechanism(s) or increasing X chromosome dose may strain dosage compensation systems and make them less effective. The extent of female bias on the X chromosomes decreases through developmental time with the establishment of MSL-mediated dosage compensation, but may do so more slowly in D. miranda than D. pseudoobscura. These results also prompt a number of questions about whether species with more sex-linked genes have more sex-specific phenotypes, and how much transcript level variance is tolerable during critical stages

  16. Genomic imprinting and maternal effect genes in haplodiploid sex determination.

    PubMed

    van de Zande, L; Verhulst, E C

    2014-01-01

    The research into the Drosophila melanogaster sex-determining system has been at the basis of all further research on insect sex determination. This further research has made it clear that, for most insect species, the presence of sufficient functional Transformer (TRA) protein in the early embryonic stage is essential for female sexual development. In Hymenoptera, functional analysis of sex determination by knockdown studies of sex-determining genes has only been performed for 2 species. The first is the social insect species Apis mellifera, the honeybee, which has single-locus complementary sex determination (CSD). The other species is the parasitoid Nasonia vitripennis, the jewel wasp. Nasonia has a non-CSD sex-determining system, described as the maternal effect genomic imprinting sex determination system (MEGISD). Here, we describe the arguments that eventually led to the formulation of MEGISD and the experimental data that supported and refined this model. We evaluate the possibility that DNA methylation lies at the basis of MEGISD and briefly address the role of genomic imprinting in non-CSD sex determination in other Hymenoptera.

  17. Homebox Genes in Normal, Preneoplastic, and Neoplastic Mammary Glands.

    DTIC Science & Technology

    1998-01-01

    homeotic gene research in mammary gland biology. The general aim of this project has been to obtain a better and ultimately more clinically useful...biology. One such group of genes is the homeotic family, which act as transcription factors, switching on or off groups of genes that specify the details...potential to explore the role of homeotic genes in mammary development and in the etiology of cancer. These experiments cannot be done in humans, of

  18. Identification of sex-specific polymorphic sequences in the goat amelogenin gene for embryo sexing.

    PubMed

    Tsai, T C; Wu, S H; Chen, H L; Tung, Y T; Cheng, W T K; Huang, J C; Chen, C M

    2011-08-01

    Amelogenin (AMEL) is a conserved gene located on the sex chromosomes of mammals. It is involved in the formation of enamel, which is the hard, white material that forms the protective outer layer of each tooth. In this study, we first cloned and determined the intron sequences of the goat AMELX and AMELY genes from female and male ear tissues. The polymorphic AMEL alleles were further analyzed by PCR-based RFLP and Southern blot hybridization analyses. Results showed that intron 5 nucleotide sequences of the goat AMELY gene contains multiple deletions/insertions and shares only 48.5% identity to intron 5 of the goat AMELX gene. Based on the polymorphic AMEL intron sequences, a set of sex-specific triplex primers was designed to PCR amplify a single fragment of 264 bp from the X chromosome of female goats and 2 fragments of 264 and 206 bp from the X and Y chromosomes, respectively, of male goats. An increased sensitivity for sex determination was reached with a single blastomere at the blastula stage isolated from goat embryos. A total of 43 goat embryos were used to estimate a 100% accuracy rate of this method confirmed by chromosomal karyotyping and live births. The embryo sexing technique has been successfully applied in different strains of goats including Alpine, Saanen, Nubian, and Taiwan goats.

  19. Sex determination in flowering plants.

    PubMed Central

    Dellaporta, S L; Calderon-Urrea, A

    1993-01-01

    In many ways, plants offer unique systems through which to study sex determination. Because the production of unisexual flowers has evolved independently in many plant species, different and novel mechanisms may be operational. Hence, there is probably not one unifying mechanism that explains sex determination in plants. Advances in our understanding of sex determination will come from the analysis of the genetics, molecular biology, and biochemistry of genes controlling sexual determination in plants. Several excellent model systems for bisexual floral development (Arabidopsis and Antirrhinum), monoecy (maize), and dioecy (Silene, asparagus, and mercury) are available for such analyses. The important questions that remain concern the mechanism of action of sex determination genes and their interrelationship, if any, with homeotic genes that determine the sexual identity of floral organ primordia. At the physiological level, the connection between hormone signaling and sexuality is not well understood, although significant correlations have been discovered. Finally, once the genes that regulate these processes are identified, cloned, and studied, new strategies for the manipulation of sexuality in plants should be forthcoming. PMID:8281039

  20. Sex determination in flowering plants.

    PubMed

    Dellaporta, S L; Calderon-Urrea, A

    1993-10-01

    In many ways, plants offer unique systems through which to study sex determination. Because the production of unisexual flowers has evolved independently in many plant species, different and novel mechanisms may be operational. Hence, there is probably not one unifying mechanism that explains sex determination in plants. Advances in our understanding of sex determination will come from the analysis of the genetics, molecular biology, and biochemistry of genes controlling sexual determination in plants. Several excellent model systems for bisexual floral development (Arabidopsis and Antirrhinum), monoecy (maize), and dioecy (Silene, asparagus, and mercury) are available for such analyses. The important questions that remain concern the mechanism of action of sex determination genes and their interrelationship, if any, with homeotic genes that determine the sexual identity of floral organ primordia. At the physiological level, the connection between hormone signaling and sexuality is not well understood, although significant correlations have been discovered. Finally, once the genes that regulate these processes are identified, cloned, and studied, new strategies for the manipulation of sexuality in plants should be forthcoming.

  1. Large Scale Gene Expression Meta-Analysis Reveals Tissue-Specific, Sex-Biased Gene Expression in Humans.

    PubMed

    Mayne, Benjamin T; Bianco-Miotto, Tina; Buckberry, Sam; Breen, James; Clifton, Vicki; Shoubridge, Cheryl; Roberts, Claire T

    2016-01-01

    The severity and prevalence of many diseases are known to differ between the sexes. Organ specific sex-biased gene expression may underpin these and other sexually dimorphic traits. To further our understanding of sex differences in transcriptional regulation, we performed meta-analyses of sex biased gene expression in multiple human tissues. We analyzed 22 publicly available human gene expression microarray data sets including over 2500 samples from 15 different tissues and 9 different organs. Briefly, by using an inverse-variance method we determined the effect size difference of gene expression between males and females. We found the greatest sex differences in gene expression in the brain, specifically in the anterior cingulate cortex, (1818 genes), followed by the heart (375 genes), kidney (224 genes), colon (218 genes), and thyroid (163 genes). More interestingly, we found different parts of the brain with varying numbers and identity of sex-biased genes, indicating that specific cortical regions may influence sexually dimorphic traits. The majority of sex-biased genes in other tissues such as the bladder, liver, lungs, and pancreas were on the sex chromosomes or involved in sex hormone production. On average in each tissue, 32% of autosomal genes that were expressed in a sex-biased fashion contained androgen or estrogen hormone response elements. Interestingly, across all tissues, we found approximately two-thirds of autosomal genes that were sex-biased were not under direct influence of sex hormones. To our knowledge this is the largest analysis of sex-biased gene expression in human tissues to date. We identified many sex-biased genes that were not under the direct influence of sex chromosome genes or sex hormones. These may provide targets for future development of sex-specific treatments for diseases.

  2. Large Scale Gene Expression Meta-Analysis Reveals Tissue-Specific, Sex-Biased Gene Expression in Humans

    PubMed Central

    Mayne, Benjamin T.; Bianco-Miotto, Tina; Buckberry, Sam; Breen, James; Clifton, Vicki; Shoubridge, Cheryl; Roberts, Claire T.

    2016-01-01

    The severity and prevalence of many diseases are known to differ between the sexes. Organ specific sex-biased gene expression may underpin these and other sexually dimorphic traits. To further our understanding of sex differences in transcriptional regulation, we performed meta-analyses of sex biased gene expression in multiple human tissues. We analyzed 22 publicly available human gene expression microarray data sets including over 2500 samples from 15 different tissues and 9 different organs. Briefly, by using an inverse-variance method we determined the effect size difference of gene expression between males and females. We found the greatest sex differences in gene expression in the brain, specifically in the anterior cingulate cortex, (1818 genes), followed by the heart (375 genes), kidney (224 genes), colon (218 genes), and thyroid (163 genes). More interestingly, we found different parts of the brain with varying numbers and identity of sex-biased genes, indicating that specific cortical regions may influence sexually dimorphic traits. The majority of sex-biased genes in other tissues such as the bladder, liver, lungs, and pancreas were on the sex chromosomes or involved in sex hormone production. On average in each tissue, 32% of autosomal genes that were expressed in a sex-biased fashion contained androgen or estrogen hormone response elements. Interestingly, across all tissues, we found approximately two-thirds of autosomal genes that were sex-biased were not under direct influence of sex hormones. To our knowledge this is the largest analysis of sex-biased gene expression in human tissues to date. We identified many sex-biased genes that were not under the direct influence of sex chromosome genes or sex hormones. These may provide targets for future development of sex-specific treatments for diseases. PMID:27790248

  3. Sex-biased expression of sex-differentiating genes FOXL2 and FGF9 in American alligators, Alligator mississippiensis

    PubMed Central

    Janes, Daniel E.; Elsey, Ruth M.; Langan, Esther M.; Valenzuela, Nicole; Edwards, Scott V.

    2013-01-01

    Across amniotes, sex-determining mechanisms exhibit great variation yet the genes that govern sexual differentiation are largely conserved. Studies of evolution of sex-determining and sex-differentiating genes require an exhaustive characterization of functions of those genes such as FOXL2 and FGF9. FOXL2 is associated with ovarian development and FGF9 is known to play a role in testicular organogenesis in mammals and other amniotes. As a step toward characterization of the evolutionary history of sexual development, we measured expression of FOXL2 and FGF9 across three developmental stages and eight juvenile tissue types in male and female American alligators, Alligator mississippiensis. We report surprisingly high expression of FOXL2 before the stage of embryonic development when sex is determined in response to temperature and sustained and variable expression of FGF9 in juvenile male but not female tissue types. Novel characterization of gene expression in reptiles with temperature-dependent sex determination such as American alligators may inform the evolution of sex-determining and sex-differentiating gene networks as they suggest alternative functions from which the genes may have been exapted. Future functional profiling of sex-differentiating genes should similarly follow other genes and other species to enable a broad comparison across sex-determining mechanisms. PMID:23689672

  4. Sex-biased expression of sex-differentiating genes FOXL2 and FGF9 in American alligators, alligator Mississippiensis.

    PubMed

    Janes, D E; Elsey, R M; Langan, E M; Valenzuela, N; Edwards, S V

    2013-01-01

    Across amniotes, sex-determining mechanisms exhibit great variation, yet the genes that govern sexual differentiation are largely conserved. Studies of evolution of sex-determining and sex-differentiating genes require an exhaustive characterization of functions of those genes such as FOXL2 and FGF9. FOXL2 is associated with ovarian development, and FGF9 is known to play a role in testicular organogenesis in mammals and other amniotes. As a step toward characterization of the evolutionary history of sexual development, we measured expression of FOXL2 and FGF9 across 3 developmental stages and 8 juvenile tissue types in male and female American alligators, Alligator mississippiensis. We report surprisingly high expression of FOXL2 before the stage of embryonic development when sex is determined in response to temperature, and sustained and variable expression of FGF9 in juvenile male, but not female tissue types. Novel characterization of gene expression in reptiles with temperature-dependent sex determination such as American alligators may inform the evolution of sex-determining and sex-differentiating gene networks, as they suggest alternative functions from which the genes may have been exapted. Future functional profiling of sex-differentiating genes should similarly follow other genes and other species to enable a broad comparison across sex-determining mechanisms. Copyright © 2013 S. Karger AG, Basel.

  5. Onset of sex differentiation: dialog between genes and cells.

    PubMed

    Merchant-Larios, H; Moreno-Mendoza, N

    2001-01-01

    During the late 1940s, Alfred Jost demonstrated that mammalian sex differentiation begins in fetal testis, producing two factors necessary for the establishment of phenotypic males. Castrated embryos prior to testis differentiation led to phenotypic female differentiation. Jost proposed the existence of a testis-determining factor (TDF), elucidated in 1990 and named SRY for humans and Sry for mice. Thereafter, an increasing list of genes expressed in the genital ridges of mouse embryos at the onset of gonad differentiation has appeared. To date, it is clear that complete understanding of the mechanisms underlying gonadal sex differentiation in mammals requires identification of key cell lineages in which gonadal-specific genes are expressed. Here, a correlation between known gene expression and gonadal morphologic changes is attempted.

  6. Hox-mediated regulation of doublesex sculpts sex-specific abdomen morphology in Drosophila.

    PubMed

    Wang, Wei; Yoder, John H

    2012-06-01

    Hox transcription factors are deeply conserved proteins that guide development through regulation of diverse target genes. Furthermore, alteration in Hox target cis-regulation has been proposed as a major mechanism of animal morphological evolution. Crucial to understanding how homeotic genes sculpt the developing body and contribute to the evolution of form is identification and characterization of regulatory targets. Because target specificity is achieved through physical or genetic interactions with cofactors or co-regulators, characterizing interactions between homeotic genes and regulatory partners is also critical. In Drosophila melanogaster, sexually dimorphic abdominal morphology results from sex-specific gene regulation mediated by the Hox protein Abdominal-B (Abd-B) and products of the sex-determination gene doublesex (dsx). Together these transcription factors regulate numerous sex-specific characters, including pigmentation, cuticle morphology, and abdominal segment number. We show Dsx expression in the developing D. melanogaster pupal abdomen is spatiotemporally dynamic, correlating with segments that undergo sexually dimorphic morphogenesis. Furthermore, our genetic analyses show Dsx expression is Abd-B dependent. Doublesex and Abd-B are not only requisite co-regulators of sexually dimorphic abdominal morphology. We propose that dsx is itself a transcriptional target of Abd-B. These data present a testable hypothesis about the evolution of sexually dimorphic segment number in Diptera. Copyright © 2012 Wiley Periodicals, Inc.

  7. Breaking evolutionary and pleiotropic constraints in mammals: On sloths, manatees and homeotic mutations

    PubMed Central

    2011-01-01

    Background Mammals as a rule have seven cervical vertebrae, except for sloths and manatees. Bateson proposed that the change in the number of cervical vertebrae in sloths is due to homeotic transformations. A recent hypothesis proposes that the number of cervical vertebrae in sloths is unchanged and that instead the derived pattern is due to abnormal primaxial/abaxial patterning. Results We test the detailed predictions derived from both hypotheses for the skeletal patterns in sloths and manatees for both hypotheses. We find strong support for Bateson's homeosis hypothesis. The observed vertebral and rib patterns cannot be explained by changes in primaxial/abaxial patterning. Vertebral patterns in sloths and manatees are similar to those in mice and humans with abnormal numbers of cervical vertebrae: incomplete and asymmetric homeotic transformations are common and associated with skeletal abnormalities. In sloths the homeotic vertebral shift involves a large part of the vertebral column. As such, similarity is greatest with mice mutant for genes upstream of Hox. Conclusions We found no skeletal abnormalities in specimens of sister taxa with a normal number of cervical vertebrae. However, we always found such abnormalities in conspecifics with an abnormal number, as in many of the investigated dugongs. These findings strongly support the hypothesis that the evolutionary constraints on changes of the number of cervical vertebrae in mammals is due to deleterious pleitropic effects. We hypothesize that in sloths and manatees low metabolic and activity rates severely reduce the usual stabilizing selection, allowing the breaking of the pleiotropic constraints. This probably also applies to dugongs, although to a lesser extent. PMID:21548920

  8. Breaking evolutionary and pleiotropic constraints in mammals: On sloths, manatees and homeotic mutations.

    PubMed

    Varela-Lasheras, Irma; Bakker, Alexander J; van der Mije, Steven D; Metz, Johan Aj; van Alphen, Joris; Galis, Frietson

    2011-05-06

    Mammals as a rule have seven cervical vertebrae, except for sloths and manatees. Bateson proposed that the change in the number of cervical vertebrae in sloths is due to homeotic transformations. A recent hypothesis proposes that the number of cervical vertebrae in sloths is unchanged and that instead the derived pattern is due to abnormal primaxial/abaxial patterning. We test the detailed predictions derived from both hypotheses for the skeletal patterns in sloths and manatees for both hypotheses. We find strong support for Bateson's homeosis hypothesis. The observed vertebral and rib patterns cannot be explained by changes in primaxial/abaxial patterning. Vertebral patterns in sloths and manatees are similar to those in mice and humans with abnormal numbers of cervical vertebrae: incomplete and asymmetric homeotic transformations are common and associated with skeletal abnormalities. In sloths the homeotic vertebral shift involves a large part of the vertebral column. As such, similarity is greatest with mice mutant for genes upstream of Hox. We found no skeletal abnormalities in specimens of sister taxa with a normal number of cervical vertebrae. However, we always found such abnormalities in conspecifics with an abnormal number, as in many of the investigated dugongs. These findings strongly support the hypothesis that the evolutionary constraints on changes of the number of cervical vertebrae in mammals is due to deleterious pleitropic effects. We hypothesize that in sloths and manatees low metabolic and activity rates severely reduce the usual stabilizing selection, allowing the breaking of the pleiotropic constraints. This probably also applies to dugongs, although to a lesser extent.

  9. A competition mechanism for a homeotic neuron identity transformation in C. elegans.

    PubMed

    Gordon, Patricia M; Hobert, Oliver

    2015-07-27

    Neuron identity transformations occur upon removal of specific regulatory factors in many different cellular contexts, thereby revealing the fundamental principle of alternative cell identity choices made during nervous system development. One common molecular interpretation of such homeotic cell identity transformations is that a regulatory factor has a dual function in activating genes defining one cellular identity and repressing genes that define an alternative identity. We provide evidence for an alternative, competition-based mechanism. We show that the MEC-3 LIM homeodomain protein can outcompete the execution of a neuropeptidergic differentiation program by direct interaction with the UNC-86/Brn3 POU homeodomain protein. MEC-3 thereby prevents UNC-86 from collaborating with the Zn finger transcription factor PAG-3/Gfi to induce peptidergic neuron identity and directs UNC-86 to induce an alternative differentiation program toward a glutamatergic neuronal identity. Homeotic control of neuronal identity programs has implications for the evolution of neuronal cell types. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. B-function expression in the flower center underlies the homeotic phenotype of Lacandonia schismatica (Triuridaceae).

    PubMed

    Álvarez-Buylla, Elena R; Ambrose, Barbara A; Flores-Sandoval, Eduardo; Englund, Marie; Garay-Arroyo, Adriana; García-Ponce, Berenice; de la Torre-Bárcena, Eduardo; Espinosa-Matías, Silvia; Martínez, Esteban; Piñeyro-Nelson, Alma; Engström, Peter; Meyerowitz, Elliot M

    2010-11-01

    Spontaneous homeotic transformations have been described in natural populations of both plants and animals, but little is known about the molecular-genetic mechanisms underlying these processes in plants. In the ABC model of floral organ identity in Arabidopsis thaliana, the B- and C-functions are necessary for stamen morphogenesis, and C alone is required for carpel identity. We provide ABC model-based molecular-genetic evidence that explains the unique inside-out homeotic floral organ arrangement of the monocotyledonous mycoheterotroph species Lacandonia schismatica (Triuridaceae) from Mexico. Whereas a quarter million flowering plant species bear central carpels surrounded by stamens, L. schismatica stamens occur in the center of the flower and are surrounded by carpels. The simplest explanation for this is that the B-function is displaced toward the flower center. Our analyses of the spatio-temporal pattern of B- and C-function gene expression are consistent with this hypothesis. The hypothesis is further supported by conservation between the B-function genes of L. schismatica and Arabidopsis, as the former are able to rescue stamens in Arabidopsis transgenic complementation lines, and Ls-AP3 and Ls-PI are able to interact with each other and with the corresponding Arabidopsis B-function proteins in yeast. Thus, relatively simple molecular modifications may underlie important morphological shifts in natural populations of extant plant taxa.

  11. Untangling the Contributions of Sex-Specific Gene Regulation and X-Chromosome Dosage to Sex-Biased Gene Expression in Caenorhabditis elegans

    PubMed Central

    Kramer, Maxwell; Rao, Prashant; Ercan, Sevinc

    2016-01-01

    Dosage compensation mechanisms equalize the level of X chromosome expression between sexes. Yet the X chromosome is often enriched for genes exhibiting sex-biased, i.e., imbalanced expression. The relationship between X chromosome dosage compensation and sex-biased gene expression remains largely unexplored. Most studies determine sex-biased gene expression without distinguishing between contributions from X chromosome copy number (dose) and the animal’s sex. Here, we uncoupled X chromosome dose from sex-specific gene regulation in Caenorhabditis elegans to determine the effect of each on X expression. In early embryogenesis, when dosage compensation is not yet fully active, X chromosome dose drives the hermaphrodite-biased expression of many X-linked genes, including several genes that were shown to be responsible for hermaphrodite fate. A similar effect is seen in the C. elegans germline, where X chromosome dose contributes to higher hermaphrodite X expression, suggesting that lack of dosage compensation in the germline may have a role in supporting higher expression of X chromosomal genes with female-biased functions in the gonad. In the soma, dosage compensation effectively balances X expression between the sexes. As a result, somatic sex-biased expression is almost entirely due to sex-specific gene regulation. These results suggest that lack of dosage compensation in different tissues and developmental stages allow X chromosome copy number to contribute to sex-biased gene expression and function. PMID:27356611

  12. Untangling the Contributions of Sex-Specific Gene Regulation and X-Chromosome Dosage to Sex-Biased Gene Expression in Caenorhabditis elegans.

    PubMed

    Kramer, Maxwell; Rao, Prashant; Ercan, Sevinc

    2016-09-01

    Dosage compensation mechanisms equalize the level of X chromosome expression between sexes. Yet the X chromosome is often enriched for genes exhibiting sex-biased, i.e., imbalanced expression. The relationship between X chromosome dosage compensation and sex-biased gene expression remains largely unexplored. Most studies determine sex-biased gene expression without distinguishing between contributions from X chromosome copy number (dose) and the animal's sex. Here, we uncoupled X chromosome dose from sex-specific gene regulation in Caenorhabditis elegans to determine the effect of each on X expression. In early embryogenesis, when dosage compensation is not yet fully active, X chromosome dose drives the hermaphrodite-biased expression of many X-linked genes, including several genes that were shown to be responsible for hermaphrodite fate. A similar effect is seen in the C. elegans germline, where X chromosome dose contributes to higher hermaphrodite X expression, suggesting that lack of dosage compensation in the germline may have a role in supporting higher expression of X chromosomal genes with female-biased functions in the gonad. In the soma, dosage compensation effectively balances X expression between the sexes. As a result, somatic sex-biased expression is almost entirely due to sex-specific gene regulation. These results suggest that lack of dosage compensation in different tissues and developmental stages allow X chromosome copy number to contribute to sex-biased gene expression and function.

  13. The genomic distribution of sex-biased genes in drosophila serrata: X chromosome demasculinization, feminization, and hyperexpression in both sexes.

    PubMed

    Allen, Scott L; Bonduriansky, Russell; Chenoweth, Stephen F

    2013-01-01

    The chromosomal distribution of genes with sex-biased expression is often nonrandom, and in species with XY sex chromosome systems, it is common to observe a deficit of X-linked male-biased genes and an excess of X-linked female-biased genes. One explanation for this pattern is that sex-specific selection has shaped the gene content of the X. Alternatively, the deficit of male-biased and excess of female-biased genes could be an artifact of differences between the sexes in the global expression level of their X chromosome(s), perhaps brought about by a lack of dosage compensation in males and hyperexpression in females. In the montium fruit fly, Drosophila serrata, both these explanations can account for a deficit of male-biased and excess of female-biased X-linked genes. Using genome-wide expression data from multiple male and female tissues (n = 176 hybridizations), we found that testis- and accessory gland-specific genes are underrepresented whereas female ovary-specific genes are overrepresented on the X chromosome, suggesting that X-linkage is disfavored for male function genes but favored for female function genes. However, genes with such sex-specific functions did not fully account for the deficit of male-biased and excess of female-biased X-linked genes. We did, however, observe sex differences in the global expression level of the X chromosome and autosomes. Surprisingly, and in contrast to other species where a lack of dosage compensation in males is responsible, we found that hyperexpression of X-linked genes in both sexes leads to this imbalance in D. serrata. Our results highlight how common genomic distributions of sex-biased genes, even among closely related species, may arise via quite different evolutionary processes.

  14. The Genomic Distribution of Sex-Biased Genes in Drosophila serrata: X Chromosome Demasculinization, Feminization, and Hyperexpression in Both Sexes

    PubMed Central

    Allen, Scott L.; Bonduriansky, Russell; Chenoweth, Stephen F.

    2013-01-01

    The chromosomal distribution of genes with sex-biased expression is often nonrandom, and in species with XY sex chromosome systems, it is common to observe a deficit of X-linked male-biased genes and an excess of X-linked female-biased genes. One explanation for this pattern is that sex-specific selection has shaped the gene content of the X. Alternatively, the deficit of male-biased and excess of female-biased genes could be an artifact of differences between the sexes in the global expression level of their X chromosome(s), perhaps brought about by a lack of dosage compensation in males and hyperexpression in females. In the montium fruit fly, Drosophila serrata, both these explanations can account for a deficit of male-biased and excess of female-biased X-linked genes. Using genome-wide expression data from multiple male and female tissues (n = 176 hybridizations), we found that testis- and accessory gland-specific genes are underrepresented whereas female ovary-specific genes are overrepresented on the X chromosome, suggesting that X-linkage is disfavored for male function genes but favored for female function genes. However, genes with such sex-specific functions did not fully account for the deficit of male-biased and excess of female-biased X-linked genes. We did, however, observe sex differences in the global expression level of the X chromosome and autosomes. Surprisingly, and in contrast to other species where a lack of dosage compensation in males is responsible, we found that hyperexpression of X-linked genes in both sexes leads to this imbalance in D. serrata. Our results highlight how common genomic distributions of sex-biased genes, even among closely related species, may arise via quite different evolutionary processes. PMID:24084777

  15. Mouse model systems to study sex chromosome genes and behavior: relevance to humans.

    PubMed

    Cox, Kimberly H; Bonthuis, Paul J; Rissman, Emilie F

    2014-10-01

    Sex chromosome genes directly influence sex differences in behavior. The discovery of the Sry gene on the Y chromosome (Gubbay et al., 1990; Koopman et al., 1990) substantiated the sex chromosome mechanistic link to sex differences. Moreover, the pronounced connection between X chromosome gene mutations and mental illness produces a strong sex bias in these diseases. Yet, the dominant explanation for sex differences continues to be the gonadal hormones. Here we review progress made on behavioral differences in mouse models that uncouple sex chromosome complement from gonadal sex. We conclude that many social and cognitive behaviors are modified by sex chromosome complement, and discuss the implications for human research. Future directions need to include identification of the genes involved and interactions with these genes and gonadal hormones.

  16. Mouse model systems to study sex chromosome genes and behavior: relevance to humans

    PubMed Central

    Cox, Kimberly H.; Bonthuis, Paul J.; Rissman, Emilie F.

    2014-01-01

    Sex chromosome genes directly influence sex differences in behavior. The discovery of the Sry gene on the Y chromosome (Gubbay et al., 1990; Koopman et al., 1990) substantiated the sex chromosome mechanistic link to sex differences. Moreover, the pronounced connection between X chromosome gene mutations and mental illness produces a strong sex bias in these diseases. Yet, the dominant explanation for sex differences continues to be the gonadal hormones. Here we review progress made on behavioral differences in mouse models that uncouple sex chromosome complement from gonadal sex. We conclude that many social and cognitive behaviors are modified by sex chromosome complement, and discuss the implications for human research. Future directions need to include identification of the genes involved and interactions with these genes and gonadal hormones. PMID:24388960

  17. The great escape: Active genes on inactive sex chromosomes and their evolutionary implications.

    PubMed

    Sin, Ho-Su; Namekawa, Satoshi H

    2013-09-01

    Epigenetic mechanisms precisely regulate sex chromosome inactivation as well as genes that escape the silencing process. In male germ cells, DNA damage response factor RNF8 establishes active epigenetic modifications on the silent sex chromosomes during meiosis, and activates escape genes during a state of sex chromosome-wide silencing in postmeiotic spermatids. During the course of evolution, the gene content of escape genes in postmeiotic spermatids recently diverged on the sex chromosomes. This evolutionary feature mirrors the epigenetic processes of sex chromosomes in germ cells. In this article, we describe how epigenetic processes have helped to shape the evolution of sex chromosome-linked genes. Furthermore, we compare features of escape genes on sex chromosomes in male germ cells to escape genes located on the single X chromosome silenced during X-inactivation in females, clarifying the distinct evolutionary implications between male and female escape genes.

  18. Homeotic effects, somitogenesis and the evolution of vertebral numbers in recent and fossil amniotes.

    PubMed

    Müller, Johannes; Scheyer, Torsten M; Head, Jason J; Barrett, Paul M; Werneburg, Ingmar; Ericson, Per G P; Pol, Diego; Sánchez-Villagra, Marcelo R

    2010-02-02

    The development of distinct regions in the amniote vertebral column results from somite formation and Hox gene expression, with the adult morphology displaying remarkable variation among lineages. Mammalian regionalization is reportedly very conservative or even constrained, but there has been no study investigating vertebral count variation across Amniota as a whole, undermining attempts to understand the phylogenetic, ecological, and developmental factors affecting vertebral column variation. Here, we show that the mammalian (synapsid) and reptilian lineages show early in their evolutionary histories clear divergences in axial developmental plasticity, in terms of both regionalization and meristic change, with basal synapsids sharing the conserved axial configuration of crown mammals, and basal reptiles demonstrating the plasticity of extant taxa. We conducted a comprehensive survey of presacral vertebral counts across 436 recent and extinct amniote taxa. Vertebral counts were mapped onto a generalized amniote phylogeny as well as individual ingroup trees, and ancestral states were reconstructed by using squared-change parsimony. We also calculated the relationship between presacral and cervical numbers to infer the relative influence of homeotic effects and meristic changes and found no correlation between somitogenesis and Hox-mediated regionalization. Although conservatism in presacral numbers characterized early synapsid lineages, in some cases reptiles and synapsids exhibit the same developmental innovations in response to similar selective pressures. Conversely, increases in body mass are not coupled with meristic or homeotic changes, but mostly occur in concert with postembryonic somatic growth. Our study highlights the importance of fossils in large-scale investigations of evolutionary developmental processes.

  19. Homeotic effects, somitogenesis and the evolution of vertebral numbers in recent and fossil amniotes

    PubMed Central

    Müller, Johannes; Scheyer, Torsten M.; Head, Jason J.; Barrett, Paul M.; Werneburg, Ingmar; Ericson, Per G. P.; Pol, Diego; Sánchez-Villagra, Marcelo R.

    2010-01-01

    The development of distinct regions in the amniote vertebral column results from somite formation and Hox gene expression, with the adult morphology displaying remarkable variation among lineages. Mammalian regionalization is reportedly very conservative or even constrained, but there has been no study investigating vertebral count variation across Amniota as a whole, undermining attempts to understand the phylogenetic, ecological, and developmental factors affecting vertebral column variation. Here, we show that the mammalian (synapsid) and reptilian lineages show early in their evolutionary histories clear divergences in axial developmental plasticity, in terms of both regionalization and meristic change, with basal synapsids sharing the conserved axial configuration of crown mammals, and basal reptiles demonstrating the plasticity of extant taxa. We conducted a comprehensive survey of presacral vertebral counts across 436 recent and extinct amniote taxa. Vertebral counts were mapped onto a generalized amniote phylogeny as well as individual ingroup trees, and ancestral states were reconstructed by using squared-change parsimony. We also calculated the relationship between presacral and cervical numbers to infer the relative influence of homeotic effects and meristic changes and found no correlation between somitogenesis and Hox-mediated regionalization. Although conservatism in presacral numbers characterized early synapsid lineages, in some cases reptiles and synapsids exhibit the same developmental innovations in response to similar selective pressures. Conversely, increases in body mass are not coupled with meristic or homeotic changes, but mostly occur in concert with postembryonic somatic growth. Our study highlights the importance of fossils in large-scale investigations of evolutionary developmental processes. PMID:20080660

  20. Evidence for Different Origins of Sex Chromosomes in Closely Related Oryzias Fishes: Substitution of the Master Sex-Determining Gene

    PubMed Central

    Tanaka, Keita; Takehana, Yusuke; Naruse, Kiyoshi; Hamaguchi, Satoshi; Sakaizumi, Mitsuru

    2007-01-01

    The medaka Oryzias latipes and its two sister species, O. curvinotus and O. luzonensis, possess an XX–XY sex-determination system. The medaka sex-determining gene DMY has been identified on the orthologous Y chromosome [O. latipes linkage group 1 (LG1)] of O. curvinotus. However, DMY has not been discovered in other Oryzias species. These results and molecular phylogeny suggest that DMY was generated recently [∼10 million years ago (MYA)] by gene duplication of DMRT1 in a common ancestor of O. latipes and O. curvinotus. We identified seven sex-linked markers from O. luzonensis (sister species of O. curvinotus) and constructed a sex-linkage map. Surprisingly, all seven sex-linked markers were located on an autosomal linkage group (LG12) of O. latipes. As suggested by the phylogenetic tree, the sex chromosomes of O. luzonensis should be “younger” than those of O. latipes. In the lineage leading to O. luzonensis after separation from O. curvinotus ∼5 MYA, a novel sex-determining gene may have arisen and substituted for DMY. Oryzias species should provide a useful model for evolution of the master sex-determining gene and differentiation of sex chromosomes from autosomes. PMID:17947439

  1. Disorders of sex development: new genes, new concepts.

    PubMed

    Ono, Makoto; Harley, Vincent R

    2013-02-01

    Formerly known as 'intersex' conditions, disorders of sex development (DSDs) are congenital conditions in which chromosomal, gonadal or anatomical sex is atypical. A complete revision of the nomenclature and classification of DSDs has been undertaken, which emphasizes the genetic aetiology of these disorders and discards pejorative terms. Uptake of the new terminology is widespread. DSDs affecting gonadal development are perhaps the least well understood. Unravelling the molecular mechanisms underlying gonadal development has revealed new causes of DSDs, although a specific molecular diagnosis is made in only ∼20% of patients. Conversely, identification of the molecular causes of DSDs has provided insight into the mechanisms of gonadal development. Studies of N-ethyl-N-nitrosourea mutagenesis in the mouse, and multigene diagnostic screening and genome-wide approaches, such as array-comparative genomic hybridization and next-generation sequencing, in patients with DSDs are accelerating the discovery of genes involved in gonadal development and DSDs. Furthermore, long-range gene regulatory mutations and multiple gene mutations are emerging as new causes of DSDs. Patients with DSDs, their parents and medical staff are confronted with challenging decisions regarding gender assignment, genital surgery and lifelong care. These advances are refining prognostic prediction and systematically improving the diagnosis and long-term management of children with DSDs.

  2. Malformations of the axial skeleton in Museum Vrolik I: homeotic transformations and numerical anomalies.

    PubMed

    Oostra, Roelof-Jan; Hennekam, Raoul C M; de Rooij, Laurens; Moorman, Antoon F M

    2005-04-30

    The Museum Vrolik collection of anatomical specimens in Amsterdam, The Netherlands, comprises over 5,000 specimens of human and animal anatomy, embryology, pathology, and congenital anomalies. Recently, we rediagnosed a subset of the collection comprising dried human trunk skeletons and cranial base preparations presenting with homeotic transformations (vertebral phenotypic shifts) and numerical vertebral anomalies. We identified 11 trunk skeletons with either anterior or posterior homeotic transformations (AHT or PHT), 5 trunk skeletons with either less or more than the normal number of vertebrae, and well over a hundred cranial base preparations with either AHT (atlas-assimilation) or PHT (occipital vertebra). We found that, although homeotic transformations and numerical anomalies are distinct conditions, both can be described in terms of mismatch between homeotic patterning and morphological segmentation of the paraxial mesoderm. Therefore these two processes are perhaps not as tightly linked as they may seem on the basis of recent molecular studies. In homeotic transformations there is a constant mismatch between homeotic patterning and morphological segmentation throughout the affected region of the vertebral column. In numerical anomalies there is a variable mismatch between homeotic patterning and morphological segmentation, either because of stretching or squeezing of the homeotic pattern or because of oligo- or polysegmentation of the presomitic mesoderm (PSM). Homeotic transformations of the axial skeleton have an incidence of about 1%-5%, apart from their occurrence in malformation syndromes. Of the various etiological possibilities, explaining their frequent but mostly sporadic occurrence, maternal hyperthermia seems an attractive candidate.

  3. Association testing to detect gene-gene interactions on sex chromosomes in trio data.

    PubMed

    Lee, Yeonok; Ghosh, Debashis; Zhang, Yu

    2013-01-01

    Autism Spectrum Disorder (ASD) occurs more often among males than females in a 4:1 ratio. Among theories used to explain the causes of ASD, the X chromosome and the Y chromosome theories attribute ASD to the X-linked mutation and the male-limited gene expressions on the Y chromosome, respectively. Despite the rationale of the theory, studies have failed to attribute the sex-biased ratio to the significant linkage or association on the regions of interest on X chromosome. We further study the gender biased ratio by examining the possible interaction effects between two genes in the sex chromosomes. We propose a logistic regression model with mixed effects to detect gene-gene interactions on sex chromosomes. We investigated the power and type I error rates of the approach for a range of minor allele frequencies and varying linkage disequilibrium between markers and QTLs. We also evaluated the robustness of the model to population stratification. We applied the model to a trio-family data set with an ASD affected male child to study gene-gene interactions on sex chromosomes.

  4. Extreme selection in humans against homeotic transformations of cervical vertebrae.

    PubMed

    Galis, Frietson; Van Dooren, Tom J M; Feuth, Johan D; Metz, Johan A J; Witkam, Andrea; Ruinard, Sebastiaan; Steigenga, Marc J; Wijnaendts, Liliane C D

    2006-12-01

    Why do all mammals, except for sloths and manatees, have exactly seven cervical vertebrae? In other vertebrates and other regions, the vertebral number varies considerably. We investigated whether natural selection constrains the number of cervical vertebrae in humans. To this end, we determined the incidence of cervical ribs and other homeotic vertebral changes in radiographs of deceased human fetuses and infants, and analyzed several existing datasets on the incidence in infants and adults. Our data show that homeotic transformations that change the number of cervical vertebrae are extremely common in humans, but are strongly selected against: almost all individuals die before reproduction. Selection is most probably indirect, caused by a strong coupling of such changes with major congenital abnormalities. Changes in the number of thoracic vertebrae appear to be subject to weaker selection, in good correspondence with the weaker evolutionary constraint on these numbers. Our analysis highlights the role of prenatal selection in the conservation of our common body plan.

  5. Sex-linked genes in age-structured populations.

    PubMed

    Cornette, J L

    1978-04-01

    We study the progress towards equilibrium of the frequencies of sex-linked genes in elementary discrete time models of age-structured, overlapping generation populations. It is found that, if a finite upper age limit is assumed, the difference in the frequencies of an allele in males and females will oscillate as in the familiar non-overlapping generation models, although the oscillations may be irregular. Monotonic convergence of that difference, as found by Nagylaki (1975) in continuous-time overlapping generation models without age-structure, occurs in the models considered here only when there is no upper age limit and when there is "sufficient" overlap of generations.

  6. The floral homeotic protein APETALA2 recognizes and acts through an AT-rich sequence element.

    PubMed

    Dinh, Thanh Theresa; Girke, Thomas; Liu, Xigang; Yant, Levi; Schmid, Markus; Chen, Xuemei

    2012-06-01

    Cell fate specification in development requires transcription factors for proper regulation of gene expression. In Arabidopsis, transcription factors encoded by four classes of homeotic genes, A, B, C and E, act in a combinatorial manner to control proper floral organ identity. The A-class gene APETALA2 (AP2) promotes sepal and petal identities in whorls 1 and 2 and restricts the expression of the C-class gene AGAMOUS (AG) from whorls 1 and 2. However, it is unknown how AP2 performs these functions. Unlike the other highly characterized floral homeotic proteins containing MADS domains, AP2 has two DNA-binding domains referred to as the AP2 domains and its DNA recognition sequence is still unknown. Here, we show that the second AP2 domain in AP2 binds a non-canonical AT-rich target sequence, and, using a GUS reporter system, we demonstrate that the presence of this sequence in the AG second intron is important for the restriction of AG expression in vivo. Furthermore, we show that AP2 binds the AG second intron and directly regulates AG expression through this sequence element. Computational analysis reveals that the binding site is highly conserved in the second intron of AG orthologs throughout Brassicaceae. By uncovering a biologically relevant AT-rich target sequence, this work shows that AP2 domains have wide-ranging target specificities and provides a missing link in the mechanisms that underlie flower development. It also sets the foundation for understanding the basis of the broad biological functions of AP2 in Arabidopsis, as well as the divergent biological functions of AP2 orthologs in dicotyledonous plants.

  7. batman Interacts with Polycomb and trithorax Group Genes and Encodes a BTB/POZ Protein That Is Included in a Complex Containing GAGA Factor

    PubMed Central

    Faucheux, M.; Roignant, J.-Y.; Netter, S.; Charollais, J.; Antoniewski, C.; Théodore, L.

    2003-01-01

    Polycomb and trithorax group genes maintain the appropriate repressed or activated state of homeotic gene expression throughout Drosophila melanogaster development. We have previously identified the batman gene as a Polycomb group candidate since its function is necessary for the repression of Sex combs reduced. However, our present genetic analysis indicates functions of batman in both activation and repression of homeotic genes. The 127-amino-acid Batman protein is almost reduced to a BTB/POZ domain, an evolutionary conserved protein-protein interaction domain found in a large protein family. We show that this domain is involved in the interaction between Batman and the DNA binding GAGA factor encoded by the Trithorax-like gene. The GAGA factor and Batman codistribute on polytene chromosomes, coimmunoprecipitate from nuclear embryonic and larval extracts, and interact in the yeast two-hybrid assay. Batman, together with the GAGA factor, binds to MHS-70, a 70-bp fragment of the bithoraxoid Polycomb response element. This binding, like that of the GAGA factor, requires the presence of d(GA)n sequences. Together, our results suggest that batman belongs to a subset of the Polycomb/trithorax group of genes that includes Trithorax-like, whose products are involved in both activation and repression of homeotic genes. PMID:12556479

  8. batman Interacts with polycomb and trithorax group genes and encodes a BTB/POZ protein that is included in a complex containing GAGA factor.

    PubMed

    Faucheux, M; Roignant, J-Y; Netter, S; Charollais, J; Antoniewski, C; Théodore, L

    2003-02-01

    Polycomb and trithorax group genes maintain the appropriate repressed or activated state of homeotic gene expression throughout Drosophila melanogaster development. We have previously identified the batman gene as a Polycomb group candidate since its function is necessary for the repression of Sex combs reduced. However, our present genetic analysis indicates functions of batman in both activation and repression of homeotic genes. The 127-amino-acid Batman protein is almost reduced to a BTB/POZ domain, an evolutionary conserved protein-protein interaction domain found in a large protein family. We show that this domain is involved in the interaction between Batman and the DNA binding GAGA factor encoded by the Trithorax-like gene. The GAGA factor and Batman codistribute on polytene chromosomes, coimmunoprecipitate from nuclear embryonic and larval extracts, and interact in the yeast two-hybrid assay. Batman, together with the GAGA factor, binds to MHS-70, a 70-bp fragment of the bithoraxoid Polycomb response element. This binding, like that of the GAGA factor, requires the presence of d(GA)n sequences. Together, our results suggest that batman belongs to a subset of the Polycomb/trithorax group of genes that includes Trithorax-like, whose products are involved in both activation and repression of homeotic genes.

  9. Cloning an expressed gene shared by the human sex chromosomes

    SciTech Connect

    Darling, S.M.; Banting, G.S.; Pym, B.; Wolfe, J.; Goodfellow, P.N.

    1986-01-01

    The existence of genes shared by mammalian sex chromosomes has been predicted on both evolutionary and functional grounds. However, the only experimental evidence for such genes in humans is the cell-surface antigen encoded by loci on the X and Y chromosomes (MIC2X and MIC2Y, respectively), which is recognized by the monoclonal antibody 12E7. Using the bacteriophage lambdagt11 expression system in Escherichia coli and immunoscreening techniques, the authors have isolated a cDNA clone whose primary product is recognized by 12E7. Southern blot analysis using somatic cell hybrids containing only the human X or Y chromosomes shows that the sequences reacting with the cDNA clone are localized to the sex chromosomes. In addition, the clone hybridizes to DNAs isolated from mouse cells that have been transfected with human DNA and selected for 12E7 expression on the fluorescence-activated cell sorter. The authors conclude that the cDNA clone encodes the 12E7 antigen, which is the primary product of the MIC2 loci. The clone was used to explore sequence homology between MIC2X and MIC2Y; these loci are closely related, if not identical.

  10. Selected Polymorphisms in Sex Hormone-Related Genes, Circulating Sex Hormones and Risk of Endometrial Cancer

    PubMed Central

    Lundin, Eva; Wirgin, Isaac; Lukanova, Annekatrin; Afanasyeva, Yelena; Krogh, Vittorio; Axelsson, Tomas; Hemminki, Kari; Clendenen, Tess V.; Arslan, Alan A.; Ohlson, Nina; Sieri, Sabina; Roy, Nirmal; Koenig, Karen L.; Idahl, Annika; Berrino, Franco; Toniolo, Paolo; Hallmans, Göran; Försti, Asta; Muti, Paola; Lenner, Per; Shore, Roy E.; Zeleniuch-Jacquotte, Anne

    2013-01-01

    Background The role of estrogen and progesterone in the development of endometrial cancer is well documented. Few studies have examined the association of genetic variants in sex hormone-related genes with endometrial cancer risk. Methods We conducted a case-control study nested within three cohorts to examine the association of endometrial cancer risk with polymorphisms in hormone-related genes among 391 cases (92% postmenopausal at diagnosis) and 712 individually-matched controls. We also examined the association of these polymorphisms with circulating levels of sex hormones and SHBG in a cross-sectional analysis including 596 healthy postmenopausal women at blood donation (controls from this nested case-control study and from a nested case-control study of breast cancer in one of the three cohorts). Results Adjusting for endometrial cancer risk factors, the A allele of rs4775936 in CYP19 was significantly associated (ORper allele = 1.22, 95% CI = 1.01–1.47, ptrend = 0.04), while the T allele of rs10046 was marginally associated with increased risk of endometrial cancer (ORper allele = 1.20, 95% CI = 0.99 – 1.45, ptrend = 0.06). PGR rs1042838 was also marginally associated with risk (ORper allele = 1.25, 95% CI = 0.96–1.61, ptrend = 0.09). No significant association was found for the other polymorphisms, i.e. CYP1B1 rs1800440 and rs1056836, UGT1A1 rs8175347, SHBG rs6259 and ESR1 rs2234693. Rs8175347 was significantly associated with postmenopausal levels of estradiol, free estradiol and estrone and rs6259 with SHBG and estradiol. Conclusion Our findings support an association between genetic variants in CYP19, and possibly PGR, and risk of endometrial cancer. PMID:22633539

  11. The mouse X chromosome is enriched for sex-biased genes not subject to selection by meiotic sex chromosome inactivation.

    PubMed

    Khil, Pavel P; Smirnova, Natalya A; Romanienko, Peter J; Camerini-Otero, R Daniel

    2004-06-01

    Sex chromosomes are subject to sex-specific selective evolutionary forces. One model predicts that genes with sex-biased expression should be enriched on the X chromosome. In agreement with Rice's hypothesis, spermatogonial genes are over-represented on the X chromosome of mice and sex- and reproduction-related genes are over-represented on the human X chromosome. Male-biased genes are under-represented on the X chromosome in worms and flies, however. Here we show that mouse spermatogenesis genes are relatively under-represented on the X chromosome and female-biased genes are enriched on it. We used Spo11(-/-) mice blocked in spermatogenesis early in meiosis to evaluate the temporal pattern of gene expression in sperm development. Genes expressed before the Spo11 block are enriched on the X chromosome, whereas those expressed later in spermatogenesis are depleted. Inactivation of the X chromosome in male meiosis may be a universal driving force for X-chromosome demasculinization.

  12. Endogenous hepatic glucocorticoid receptor signaling coordinates sex-biased inflammatory gene expression

    PubMed Central

    Quinn, Matthew A.; Cidlowski, John A.

    2016-01-01

    An individual’s sex affects gene expression and many inflammatory diseases present in a sex-biased manner. Glucocorticoid receptors (GRs) are regulators of inflammatory genes, but their role in sex-specific responses is unclear. Our goal was to evaluate whether GR differentially regulates inflammatory gene expression in male and female mouse liver. Twenty-five percent of the 251 genes assayed by nanostring analysis were influenced by sex. Of these baseline sexually dimorphic inflammatory genes, 82% was expressed higher in female liver. Pathway analyses defined pattern-recognition receptors as the most sexually dimorphic pathway. We next exposed male and female mice to the proinflammatory stimulus LPS. Female mice had 177 genes regulated by treatment with LPS, whereas males had 149, with only 66% of LPS-regulated genes common between the sexes. To determine the contribution of GR to sexually dimorphic inflammatory genes we performed nanostring analysis on liver-specific GR knockout (LGRKO) mice in the presence or absence of LPS. Comparing LGRKO to GRflox/flox revealed that 36 genes required GR for sexually dimorphic expression, whereas 24 genes became sexually dimorphic in LGRKO. Fifteen percent of LPS-regulated genes in GRflox/flox were not regulated in male and female LGRKO mice treated with LPS. Thus, GR action is influenced by sex to regulate inflammatory gene expression.—Quinn, M. A., Cidlowski, J. A. Endogenous hepatic glucocorticoid receptor signaling coordinates sex-biased inflammatory gene expression. PMID:26581598

  13. Sexual dimorphism and the evolution of sex-biased gene expression in the brown alga ectocarpus.

    PubMed

    Lipinska, Agnieszka; Cormier, Alexandre; Luthringer, Rémy; Peters, Akira F; Corre, Erwan; Gachon, Claire M M; Cock, J Mark; Coelho, Susana M

    2015-06-01

    Males and females often have marked phenotypic differences, and the expression of these dissimilarities invariably involves sex differences in gene expression. Sex-biased gene expression has been well characterized in animal species, where a high proportion of the genome may be differentially regulated in males and females during development. Male-biased genes tend to evolve more rapidly than female-biased genes, implying differences in the strength of the selective forces acting on the two sexes. Analyses of sex-biased gene expression have focused on organisms that exhibit separate sexes during the diploid phase of the life cycle (diploid sexual systems), but the genetic nature of the sexual system is expected to influence the evolutionary trajectories of sex-biased genes. We analyze here the patterns of sex-biased gene expression in Ectocarpus, a brown alga with haploid sex determination (dioicy) and a low level of phenotypic sexual dimorphism. In Ectocarpus, female-biased genes were found to be evolving as rapidly as male-biased genes. Moreover, genes expressed at fertility showed faster rates of evolution than genes expressed in immature gametophytes. Both male- and female-biased genes had a greater proportion of sites experiencing positive selection, suggesting that their accelerated evolution is at least partly driven by adaptive evolution. Gene duplication appears to have played a significant role in the generation of sex-biased genes in Ectocarpus, expanding previous models that propose this mechanism for the resolution of sexual antagonism in diploid systems. The patterns of sex-biased gene expression in Ectocarpus are consistent both with predicted characteristics of UV (haploid) sexual systems and with the distinctive aspects of this organism's reproductive biology.

  14. Nuclear genes with sex bias in Ruditapes philippinarum (Bivalvia, veneridae): Mitochondrial inheritance and sex determination in DUI species.

    PubMed

    Milani, Liliana; Ghiselli, Fabrizio; Nuzhdin, Sergey V; Passamonti, Marco

    2013-11-01

    Mitochondria are inherited maternally in most metazoans, but in bivalves with Doubly Uniparental Inheritance (DUI) a mitochondrial lineage is transmitted through eggs (F-type), and another through sperm (M-type). In DUI species, a sex-ratio distortion of the progeny was observed: some females produce a female-biased offspring (female-biased family), others a male-biased progeny (male-biased family), and others a 50:50 sex-ratio. A peculiar segregation pattern of M-type mitochondria in DUI organisms appears to be correlated with the sex bias of these families. According to a proposed model for the inheritance of M-type mitochondria in DUI, the transmission of sperm mitochondria is controlled by three nuclear genes, named W, X, and Z. An additional S gene with different dosage effect would be involved in sex determination. In this study, we analyzed structure and localization of three transcripts (psa, birc, and anubl1) with specific sex and family biases in the Manila clam Ruditapes philippinarum. In situ hybridization confirmed the localization of these transcripts in gametogenic cells. In other animals, homologs of these genes are involved in reproduction and ubiquitination. We hypothesized that these genes may have a role in sex determination and could also be responsible for the maintenance/degradation of spermatozoon mitochondria during embryo development of the DUI species R. philippinarum, so that we propose them as candidate factors of the W/X/Z/S system.

  15. Digital transcriptome analysis of putative sex-determination genes in papaya (Carica papaya).

    PubMed

    Urasaki, Naoya; Tarora, Kazuhiko; Shudo, Ayano; Ueno, Hiroki; Tamaki, Moritoshi; Miyagi, Norimichi; Adaniya, Shinichi; Matsumura, Hideo

    2012-01-01

    Papaya (Carica papaya) is a trioecious plant species that has male, female and hermaphrodite flowers on different plants. The primitive sex chromosomes genetically determine the sex of the papaya. Although draft sequences of the papaya genome are already available, the genes for sex determination have not been identified, likely due to the complicated structure of its sex-chromosome sequences. To identify the candidate genes for sex determination, we conducted a transcriptome analysis of flower samples from male, female and hermaphrodite plants using high-throughput SuperSAGE for digital gene expression analysis. Among the short sequence tags obtained from the transcripts, 312 unique tags were specifically mapped to the primitive sex chromosome (X or Y(h)) sequences. An annotation analysis revealed that retroelements are the most abundant sequences observed in the genes corresponding to these tags. The majority of tags on the sex chromosomes were located on the X chromosome, and only 30 tags were commonly mapped to both the X and Y(h) chromosome, implying a loss of many genes on the Y(h) chromosome. Nevertheless, candidate Y(h) chromosome-specific female determination genes, including a MADS-box gene, were identified. Information on these sex chromosome-specific expressed genes will help elucidating sex determination in the papaya.

  16. Digital Transcriptome Analysis of Putative Sex-Determination Genes in Papaya (Carica papaya)

    PubMed Central

    Urasaki, Naoya; Tarora, Kazuhiko; Shudo, Ayano; Ueno, Hiroki; Tamaki, Moritoshi; Miyagi, Norimichi; Adaniya, Shinichi; Matsumura, Hideo

    2012-01-01

    Papaya (Carica papaya) is a trioecious plant species that has male, female and hermaphrodite flowers on different plants. The primitive sex chromosomes genetically determine the sex of the papaya. Although draft sequences of the papaya genome are already available, the genes for sex determination have not been identified, likely due to the complicated structure of its sex-chromosome sequences. To identify the candidate genes for sex determination, we conducted a transcriptome analysis of flower samples from male, female and hermaphrodite plants using high-throughput SuperSAGE for digital gene expression analysis. Among the short sequence tags obtained from the transcripts, 312 unique tags were specifically mapped to the primitive sex chromosome (X or Yh) sequences. An annotation analysis revealed that retroelements are the most abundant sequences observed in the genes corresponding to these tags. The majority of tags on the sex chromosomes were located on the X chromosome, and only 30 tags were commonly mapped to both the X and Yh chromosome, implying a loss of many genes on the Yh chromosome. Nevertheless, candidate Yh chromosome-specific female determination genes, including a MADS-box gene, were identified. Information on these sex chromosome-specific expressed genes will help elucidating sex determination in the papaya. PMID:22815863

  17. Sex-specific gonadal and gene expression changes throughout development in fathead minnow

    EPA Science Inventory

    Although fathead minnows (Pimephales promelas) are commonly used as a model fish in endocrine disruption studies, none have characterized sex-specific baseline expression of genes involved in sex differentiation during development in this species. Using a sex-linked DNA marker t...

  18. Sex-specific gonadal and gene expression changes throughout development in fathead minnow

    EPA Science Inventory

    Although fathead minnows (Pimephales promelas) are commonly used as a model fish in endocrine disruption studies, none have characterized sex-specific baseline expression of genes involved in sex differentiation during development in this species. Using a sex-linked DNA marker t...

  19. Zebrafish sex determination and differentiation: Involvement of FTZ-F1 genes

    PubMed Central

    von Hofsten, Jonas; Olsson, Per-Erik

    2005-01-01

    Sex determination is the process deciding the sex of a developing embryo. This is usually determined genetically; however it is a delicate process, which in many cases can be influenced by environmental factors. The mechanisms controlling zebrafish sex determination and differentiation are not known. To date no sex linked genes have been identified in zebrafish and no sex chromosomes have been identified. However, a number of genes, as presented here, have been linked to the process of sex determination or differentiation in zebrafish. The zebrafish FTZ-F1 genes are of central interest as they are involved in regulating interrenal development and thereby steroid biosynthesis, as well as that they show expression patterns congruent with reproductive tissue differentiation and function. Zebrafish can be sex reversed by exposure to estrogens, suggesting that the estrogen levels are crucial during sex differentiation. The Cyp19 gene product aromatase converts testosterone into 17 beta-estradiol, and when inhibited leads to male to female sex reversal. FTZ-F1 genes are strongly linked to steroid biosynthesis and the regulatory region of Cyp19 contains binding sites for FTZ-F1 genes, further linking FTZ-F1 to this process. The role of FTZ-F1 and other candidates for zebrafish sex determination and differentiation is in focus of this review. PMID:16281973

  20. Sequence and gene content of a large fragment of a lizard sex chromosome and evaluation of candidate sex differentiating gene R-spondin 1

    PubMed Central

    2013-01-01

    Background Scant genomic information from non-avian reptile sex chromosomes is available, and for only a few lizards, several snakes and one turtle species, and it represents only a small fraction of the total sex chromosome sequences in these species. Results We report a 352 kb of contiguous sequence from the sex chromosome of a squamate reptile, Pogona vitticeps, with a ZZ/ZW sex microchromosome system. This contig contains five protein coding genes (oprd1, rcc1, znf91, znf131, znf180), and major families of repetitive sequences with a high number of copies of LTR and non-LTR retrotransposons, including the CR1 and Bov-B LINEs. The two genes, oprd1 and rcc1 are part of a homologous syntenic block, which is conserved among amniotes. While oprd1 and rcc1 have no known function in sex determination or differentiation in amniotes, this homologous syntenic block in mammals and chicken also contains R-spondin 1 (rspo1), the ovarian differentiating gene in mammals. In order to explore the probability that rspo1 is sex determining in dragon lizards, genomic BAC and cDNA clones were mapped using fluorescence in situ hybridisation. Their location on an autosomal microchromosome pair, not on the ZW sex microchromosomes, eliminates rspo1 as a candidate sex determining gene in P. vitticeps. Conclusion Our study has characterized the largest contiguous stretch of physically mapped sex chromosome sequence (352 kb) from a ZZ/ZW lizard species. Although this region represents only a small fraction of the sex chromosomes of P. vitticeps, it has revealed several features typically associated with sex chromosomes including the accumulation of large blocks of repetitive sequences. PMID:24344927

  1. Sequence and gene content of a large fragment of a lizard sex chromosome and evaluation of candidate sex differentiating gene R-spondin 1.

    PubMed

    Ezaz, Tariq; Azad, Bhumika; O'Meally, Denis; Young, Matthew J; Matsubara, Kazumi; Edwards, Melanie J; Zhang, Xiuwen; Holleley, Clare E; Deakin, Janine E; Marshall Graves, Jennifer A; Georges, Arthur; Edwards, Scott V; Sarre, Stephen D

    2013-12-17

    Scant genomic information from non-avian reptile sex chromosomes is available, and for only a few lizards, several snakes and one turtle species, and it represents only a small fraction of the total sex chromosome sequences in these species. We report a 352 kb of contiguous sequence from the sex chromosome of a squamate reptile, Pogona vitticeps, with a ZZ/ZW sex microchromosome system. This contig contains five protein coding genes (oprd1, rcc1, znf91, znf131, znf180), and major families of repetitive sequences with a high number of copies of LTR and non-LTR retrotransposons, including the CR1 and Bov-B LINEs. The two genes, oprd1 and rcc1 are part of a homologous syntenic block, which is conserved among amniotes. While oprd1 and rcc1 have no known function in sex determination or differentiation in amniotes, this homologous syntenic block in mammals and chicken also contains R-spondin 1 (rspo1), the ovarian differentiating gene in mammals. In order to explore the probability that rspo1 is sex determining in dragon lizards, genomic BAC and cDNA clones were mapped using fluorescence in situ hybridisation. Their location on an autosomal microchromosome pair, not on the ZW sex microchromosomes, eliminates rspo1 as a candidate sex determining gene in P. vitticeps. Our study has characterized the largest contiguous stretch of physically mapped sex chromosome sequence (352 kb) from a ZZ/ZW lizard species. Although this region represents only a small fraction of the sex chromosomes of P. vitticeps, it has revealed several features typically associated with sex chromosomes including the accumulation of large blocks of repetitive sequences.

  2. Progress Report for DOE DE-FG03-98ER20317 ''Regulation of the floral homeotic gene AGAMOUS'' Current and Final Funding Period: September 1, 2002, to December 31, 2002

    SciTech Connect

    Weigel, D.

    2003-03-11

    OAK-B135 Results obtained during this funding period: (1) Phylogenetic footprinting of AG regulatory sequences Sequences necessary and sufficient for AGAMOUS (AG) expression in the center of Arabidopsis flowers are located in the second intron, which is about 3 kb in size. This intron contains binding sites for two transcription factors, LEAFY (LFY) and WUSCHEL (WUS), which are direct activators of AG. We used the new method of phylogenetic shadowing to identify new regulatory elements. Among 29 Brassicaceae, several other motifs, but not the LFY and WUS binding sites previously identified, are largely invariant. Using reporter gene analyses, we tested six of these motifs and found that they are all functionally important for activity of AG regulatory sequences in A. thaliana. (2) Repression of AG by MADS box genes A candidate for repressing AG in the shoot apical meristem has been the MADS box gene FUL, since it is expressed in the shoot apical meristem and since an activated version (FUL:VP16) leads to ectopic AG expression in the shoot apical meristem. However, there is no ectopic AG expression in full single mutants. We therefore started to generate VP16 fusions of several other MADS box genes expressed in the shoot apical meristem, to determine which of these might be candidates for FUL redundant genes. We found that AGL6:VP16 has a similar phenotype as FUL:VP16, suggesting that AGL6 and FUL interact. We are now testing this hypothesis. (3) Two candidate AG regulators, WOW and ULA Because the phylogenetic footprinting project has identified several new candidate regulatory motifs, of which at least one (the CCAATCA motif) has rather strong effects, we had decided to put the analysis of WOW and ULA on hold, and to focus on using the newly identified motifs as tools. We conduct ed yeast one-hybrid screen with two of the conserved motifs, and identified several classes of transcription factors that can interact with them. One of these is encoded by the PAN gene

  3. Sex determination in annual fishes: Searching for the master sex-determining gene in Austrolebias charrua (Cyprinodontiformes, Rivulidae)

    PubMed Central

    Arezo, María José; Papa, Nicolás; Guttierrez, Verónica; García, Graciela; Berois, Nibia

    2014-01-01

    Evolution of sex determination and differentiation in fishes involves a broad range of sex strategies (hermaphroditism, gonochorism, unisexuality, environmental and genetic sex determination). Annual fishes inhabit temporary ponds that dry out during the dry season when adults die. The embryos exhibit an atypical developmental pattern and remain buried in the bottom mud until the next rainy season. To elucidate genomic factors involved in the sex determination in annual fish, we explored the presence of a candidate sex-specific gene related to the cascade network in Austrolebias charrua. All phylogenetic analyses showed a high posterior probability of occurrence for a clade integrated by nuclear sequences (aprox. 900 bp) from both adults (male and female), with partial cDNA fragments of A. charrua from juveniles (male) and the dsx D. melanogaster gene. The expressed fragment was detected from blastula to adulthood stages showing a sexually dimorphic expression pattern. The isolated cDNA sequence is clearly related to dsx D. melanogaster gene and might be located near the top of the sex determination cascade in this species. PMID:25071401

  4. Sex determination in annual fishes: Searching for the master sex-determining gene in Austrolebias charrua (Cyprinodontiformes, Rivulidae).

    PubMed

    Arezo, María José; Papa, Nicolás; Guttierrez, Verónica; García, Graciela; Berois, Nibia

    2014-06-01

    Evolution of sex determination and differentiation in fishes involves a broad range of sex strategies (hermaphroditism, gonochorism, unisexuality, environmental and genetic sex determination). Annual fishes inhabit temporary ponds that dry out during the dry season when adults die. The embryos exhibit an atypical developmental pattern and remain buried in the bottom mud until the next rainy season. To elucidate genomic factors involved in the sex determination in annual fish, we explored the presence of a candidate sex-specific gene related to the cascade network in Austrolebias charrua. All phylogenetic analyses showed a high posterior probability of occurrence for a clade integrated by nuclear sequences (aprox. 900 bp) from both adults (male and female), with partial cDNA fragments of A. charrua from juveniles (male) and the dsx D. melanogaster gene. The expressed fragment was detected from blastula to adulthood stages showing a sexually dimorphic expression pattern. The isolated cDNA sequence is clearly related to dsx D. melanogaster gene and might be located near the top of the sex determination cascade in this species.

  5. Comparative Transcriptome Analysis Reveals Sex-Biased Gene Expression in Juvenile Chinese Mitten Crab Eriocheir sinensis

    PubMed Central

    Liu, Yuan; Hui, Min; Cui, Zhaoxia; Luo, Danli; Song, Chengwen; Li, Yingdong; Liu, Lei

    2015-01-01

    Sex-biased genes are considered to account for most of phenotypic differences between males and females. In order to explore the sex-biased gene expression in crab, we performed the whole-body transcriptome analysis in male and female juveniles of the Chinese mitten crab Eriocheir sinensis using next-generation sequencing technology. Of the 23,349 annotated unigenes, 148 were identified as sex-related genes. A total of 29 candidate genes involved in primary sex determination pathways were detected, indicating the sex determination cascade of the mitten crab might be more complex than previously supposed. Differential expression analysis showed 448 differentially expressed genes (DEGs) between the two transcriptomes. Most of DEGs were involved in processes such as metabolism and immunity, and not associated with obvious sexual function. The pathway predominantly enriched for DEGs were related to lysosome, which might reflect the differences in metabolism between males and females. Of the immune DGEs, 18 up-regulated genes in females were humoral immune factors, and eight up-regulated genes in males were pattern recognition receptors, suggesting sex differences of immune defense might exist in the mitten crab. In addition, two reproduction-related genes, vitellogenin and insulin-like androgenic gland factor, were identified to express in both sexes but with significantly higher level in males. Our research provides the first whole-body RNA sequencing of sex-specific transcriptomes for juvenile E. sinensis and will facilitate further studies on molecular mechanisms of crab sexual dimorphism. PMID:26193085

  6. Comparative Transcriptome Analysis Reveals Sex-Biased Gene Expression in Juvenile Chinese Mitten Crab Eriocheir sinensis.

    PubMed

    Liu, Yuan; Hui, Min; Cui, Zhaoxia; Luo, Danli; Song, Chengwen; Li, Yingdong; Liu, Lei

    2015-01-01

    Sex-biased genes are considered to account for most of phenotypic differences between males and females. In order to explore the sex-biased gene expression in crab, we performed the whole-body transcriptome analysis in male and female juveniles of the Chinese mitten crab Eriocheir sinensis using next-generation sequencing technology. Of the 23,349 annotated unigenes, 148 were identified as sex-related genes. A total of 29 candidate genes involved in primary sex determination pathways were detected, indicating the sex determination cascade of the mitten crab might be more complex than previously supposed. Differential expression analysis showed 448 differentially expressed genes (DEGs) between the two transcriptomes. Most of DEGs were involved in processes such as metabolism and immunity, and not associated with obvious sexual function. The pathway predominantly enriched for DEGs were related to lysosome, which might reflect the differences in metabolism between males and females. Of the immune DGEs, 18 up-regulated genes in females were humoral immune factors, and eight up-regulated genes in males were pattern recognition receptors, suggesting sex differences of immune defense might exist in the mitten crab. In addition, two reproduction-related genes, vitellogenin and insulin-like androgenic gland factor, were identified to express in both sexes but with significantly higher level in males. Our research provides the first whole-body RNA sequencing of sex-specific transcriptomes for juvenile E. sinensis and will facilitate further studies on molecular mechanisms of crab sexual dimorphism.

  7. Endogenous hepatic glucocorticoid receptor signaling coordinates sex-biased inflammatory gene expression.

    PubMed

    Quinn, Matthew A; Cidlowski, John A

    2016-02-01

    An individual's sex affects gene expression and many inflammatory diseases present in a sex-biased manner. Glucocorticoid receptors (GRs) are regulators of inflammatory genes, but their role in sex-specific responses is unclear. Our goal was to evaluate whether GR differentially regulates inflammatory gene expression in male and female mouse liver. Twenty-five percent of the 251 genes assayed by nanostring analysis were influenced by sex. Of these baseline sexually dimorphic inflammatory genes, 82% was expressed higher in female liver. Pathway analyses defined pattern-recognition receptors as the most sexually dimorphic pathway. We next exposed male and female mice to the proinflammatory stimulus LPS. Female mice had 177 genes regulated by treatment with LPS, whereas males had 149, with only 66% of LPS-regulated genes common between the sexes. To determine the contribution of GR to sexually dimorphic inflammatory genes we performed nanostring analysis on liver-specific GR knockout (LGRKO) mice in the presence or absence of LPS. Comparing LGRKO to GR(flox/flox) revealed that 36 genes required GR for sexually dimorphic expression, whereas 24 genes became sexually dimorphic in LGRKO. Fifteen percent of LPS-regulated genes in GR(flox/flox) were not regulated in male and female LGRKO mice treated with LPS. Thus, GR action is influenced by sex to regulate inflammatory gene expression.

  8. Sry and SoxE genes: How they participate in mammalian sex determination and gonadal development?

    PubMed

    She, Zhen-Yu; Yang, Wan-Xi

    2017-03-01

    In mammals, sex determination defines the differentiation of the bipotential genital ridge into either testes or ovaries. Sry, the mammalian Y-chromosomal testis-determining gene, is a master regulator of male sex determination. It acts to switch the undifferentiated genital ridge towards testis development, triggering the adoption of a male fate. Sry initiates a cascade of gene networks through the direct regulation of Sox9 expression and promotes supporting cell differentiation, Leydig cell specification, vasculature formation and testis cord development. In the absence of Sry, alternative genetic cascades, including female sex-determining genes RSPO1, Wnt4/β-catenin and Foxl2, are involved in the formation of female genitalia and the maintenance of female ovarian development. The mutual antagonisms between male and female sex-determining pathways are crucial in not just the initiation but also the maintenance of the somatic sex of the gonad throughout the organism's lifetime. Any imbalances in above sex-determining genes can cause disorders of sex development in humans and mice. In this review, we provide a detailed summary of the expression profiles, biochemical properties and developmental functions of Sry and SoxE genes in embryonic testis development and adult gonadal development. We also briefly summarize the dedicate balances between male and female sex-determining genes in mammalian sex development, with particular highlights on the molecular actions of Sry and Sox9 transcription factors.

  9. Sex Biased Gene Expression Profiling of Human Brains at Major Developmental Stages.

    PubMed

    Shi, Lei; Zhang, Zhe; Su, Bing

    2016-02-16

    There are many differences in brain structure and function between males and females. However, how these differences were manifested during development and maintained through adulthood are still unclear. Here we present a time series analyses of genome-wide transcription profiles of the human brain, and we identified genes showing sex biased expression at major developmental stages (prenatal time, early childhood, puberty time and adulthood). We observed a great number of genes (>2,000 genes) showing between-sex expression divergence at all developmental stages with the greatest number (4,164 genes) at puberty time. However, there are little overlap of sex-biased genes among the major developmental stages, an indication of dynamic expression regulation of the sex-biased genes in the brain during development. Notably, the male biased genes are highly enriched for genes involved in neurological and psychiatric disorders like schizophrenia, bipolar disorder, Alzheimer's disease and autism, while no such pattern was seen for the female-biased genes, suggesting that the differences in brain disorder susceptibility between males and females are likely rooted from the sex-biased gene expression regulation during brain development. Collectively, these analyses reveal an important role of sex biased genes in brain development and neurodevelopmental disorders.

  10. B-Function Expression in the Flower Center Underlies the Homeotic Phenotype of Lacandonia schismatica (Triuridaceae)[C][W][OA

    PubMed Central

    Álvarez-Buylla, Elena R.; Ambrose, Barbara A.; Flores-Sandoval, Eduardo; Englund, Marie; Garay-Arroyo, Adriana; García-Ponce, Berenice; de la Torre-Bárcena, Eduardo; Espinosa-Matías, Silvia; Martínez, Esteban; Piñeyro-Nelson, Alma; Engström, Peter; Meyerowitz, Elliot M.

    2010-01-01

    Spontaneous homeotic transformations have been described in natural populations of both plants and animals, but little is known about the molecular-genetic mechanisms underlying these processes in plants. In the ABC model of floral organ identity in Arabidopsis thaliana, the B- and C-functions are necessary for stamen morphogenesis, and C alone is required for carpel identity. We provide ABC model-based molecular-genetic evidence that explains the unique inside-out homeotic floral organ arrangement of the monocotyledonous mycoheterotroph species Lacandonia schismatica (Triuridaceae) from Mexico. Whereas a quarter million flowering plant species bear central carpels surrounded by stamens, L. schismatica stamens occur in the center of the flower and are surrounded by carpels. The simplest explanation for this is that the B-function is displaced toward the flower center. Our analyses of the spatio-temporal pattern of B- and C-function gene expression are consistent with this hypothesis. The hypothesis is further supported by conservation between the B-function genes of L. schismatica and Arabidopsis, as the former are able to rescue stamens in Arabidopsis transgenic complementation lines, and Ls-AP3 and Ls-PI are able to interact with each other and with the corresponding Arabidopsis B-function proteins in yeast. Thus, relatively simple molecular modifications may underlie important morphological shifts in natural populations of extant plant taxa. PMID:21119062

  11. Recent gene-capture on the UV sex chromosomes of the moss Ceratodon purpureus.

    PubMed

    McDaniel, Stuart F; Neubig, Kurt M; Payton, Adam C; Quatrano, Ralph S; Cove, David J

    2013-10-01

    Sex chromosomes evolve from ordinary autosomes through the expansion and subsequent degeneration of a region of suppressed recombination that is inherited through one sex. Here we investigate the relative timing of these processes in the UV sex chromosomes of the moss Ceratodon purpureus using molecular population genetic analyses of eight newly discovered sex-linked loci. In this system, recombination is suppressed on both the female-transmitted (U) sex chromosome and the male-transmitted (V) chromosome. Genes on both chromosomes therefore should show the deleterious effects of suppressed recombination and sex-limited transmission, while purifying selection should maintain homologs of genes essential for both sexes on both sex chromosomes. Based on analyses of eight sex-linked loci, we show that the nonrecombining portions of the U and V chromosomes expanded in at least two events (~0.6-1.3 MYA and ~2.8-3.5 MYA), after the divergence of C. purpureus from its dioecious sister species, Trichodon cylindricus and Cheilothela chloropus. Both U- and V-linked copies showed reduced nucleotide diversity and limited population structure, compared to autosomal loci, suggesting that the sex chromosomes experienced more recent selective sweeps that the autosomes. Collectively these results highlight the dynamic nature of gene composition and molecular evolution on nonrecombining portions of the U and V sex chromosomes.

  12. Using RNA-seq to determine patterns of sex-bias in gene expression in the brain of the sex-role reversed Gulf Pipefish (Syngnathus scovelli).

    PubMed

    Beal, Andria P; Martin, F Douglas; Hale, Matthew C

    2017-09-22

    Sex-bias in gene expression is a widespread mechanism for controlling the development of phenotypes that differ between males and females. Most studies on sex-bias in gene expression have focused on species that exhibit traditional sex-roles (male-male competition and female parental care). By contrast the Syngnathid fishes (sea horses, pipefish, and sea dragons) are a group of organisms where many species exhibit male brooding and sex-role reversal (female-female competition for mates and paternal parental care), and little is known about how patterns of sex-bias in gene expression vary in species with sex-role reversal. Here we utilize RNA-seq technology to investigate patterns of sex-bias in gene expression in the brain tissue of the Gulf Pipefish (Syngnathus scovelli) a species that exhibits sex-role reversal. Gene expression analysis identified 73 sex-biased genes, 26 genes upregulated in females and 47 genes upregulated in males. Gene ontology analysis found 52 terms enriched for the sex-biased genes in a wide range of pathways suggesting that multiple functions and processes differ between the sexes. We focused on two areas of interest: sex steroids/hormones and circadian rhythms, both of which exhibited sex-bias in gene expression, and are known to influence sexual development in other species. Lastly, the work presented herein contributes to a growing body of genome data available for the Syngnathids, increasing our knowledge on patterns of gene expression in these unusual fishes. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Do sex steroids exert sex-specific and/or opposite effects on gene expression in lacrimal and meibomian glands?

    PubMed

    Sullivan, David A; Jensen, Roderick V; Suzuki, Tomo; Richards, Stephen M

    2009-08-10

    We hypothesize that sex steroids induce sex-specific and/or opposite effects in the lacrimal and meibomian glands and that these actions may influence the prevalence of dry eye syndrome. The objective of this study was to begin to test this hypothesis. Lacrimal and meibomian glands were obtained from ovariectomized mice that had been treated with testosterone or control vehicle for 14 days. Samples were processed for the isolation of RNA, and analyzed for differentially expressed mRNAs using CodeLink Bioarrays and quantitative real-time PCR (qPCR) techniques. Data were compared to those obtained following testosterone treatment of orchiectomized mice, as well as after the administration of 17beta-estradiol and/or progesterone to ovariectomized mice. Our findings demonstrate that testosterone regulates the expression of thousands of genes in the lacrimal and meibomian glands of ovariectomized mice. The magnitude and extent of these hormonal effects, which encompassed numerous biological, molecular, and cellular ontologies, was tissue-dependent. Particularly notable was the androgen stimulation of meibomian gland genes related to lipid metabolic pathways, and the suppression of genes associated with keratinization. Many of the genes regulated by testosterone in female tissues were identical to those controlled by androgens in male lacrimal and meibomian glands. However, some genes were modulated in a sex-specific manner. In addition, a number of the androgen-regulated genes in female glands were altered in the opposite direction by 17beta-estradiol and/or progesterone. Our results support our hypothesis that sex steroids may induce sex-specific and/or opposite effects in the lacrimal and meibomian glands. Whether these actions contribute to the prevalence of dry eye remains to be determined.

  14. Do sex steroids exert sex-specific and/or opposite effects on gene expression in lacrimal and meibomian glands?

    PubMed Central

    Jensen, Roderick V.; Suzuki, Tomo; Richards, Stephen M.

    2009-01-01

    Purpose We hypothesize that sex steroids induce sex-specific and/or opposite effects in the lacrimal and meibomian glands and that these actions may influence the prevalence of dry eye syndrome. The objective of this study was to begin to test this hypothesis. Methods Lacrimal and meibomian glands were obtained from ovariectomized mice that had been treated with testosterone or control vehicle for 14 days. Samples were processed for the isolation of RNA, and analyzed for differentially expressed mRNAs using CodeLink Bioarrays and quantitative real-time PCR (qPCR) techniques. Data were compared to those obtained following testosterone treatment of orchiectomized mice, as well as after the administration of 17β-estradiol and/or progesterone to ovariectomized mice. Results Our findings demonstrate that testosterone regulates the expression of thousands of genes in the lacrimal and meibomian glands of ovariectomized mice. The magnitude and extent of these hormonal effects, which encompassed numerous biological, molecular, and cellular ontologies, was tissue-dependent. Particularly notable was the androgen stimulation of meibomian gland genes related to lipid metabolic pathways, and the suppression of genes associated with keratinization. Many of the genes regulated by testosterone in female tissues were identical to those controlled by androgens in male lacrimal and meibomian glands. However, some genes were modulated in a sex-specific manner. In addition, a number of the androgen-regulated genes in female glands were altered in the opposite direction by 17β-estradiol and/or progesterone. Conclusions Our results support our hypothesis that sex steroids may induce sex-specific and/or opposite effects in the lacrimal and meibomian glands. Whether these actions contribute to the prevalence of dry eye remains to be determined. PMID:19693291

  15. Sex and the Single Cell. I. on the Action of Major Loci Affecting Sex Determination in DROSOPHILA MELANOGASTER

    PubMed Central

    Baker, Bruce S.; Ridge, Kimberly A.

    1980-01-01

    major regulatory loci that control the batteries of genes necessary for the development of many, and perhaps all, secondary sexual characteristics.—The striking similarities between the properties of these loci and those of the homeotic loci that determine segmental and subsegmental specialization during development suggest that the basic mechanisms of regulation are the same in the two situations. The phenotypes and interactions of these sex-determination mutants provide the basis for the model of how the wild-type alleles of these loci act together to effect normal sex determination. Implications of these observations for the function of other homeotic loci are discussed. PMID:6771185

  16. Sex-Biased Temporal Gene Expression in Male and Female Floral Buds of Seabuckthorn (Hippophae rhamnoides)

    PubMed Central

    Chawla, Aseem; Stobdan, Tsering; Srivastava, Ravi B.; Jaiswal, Varun; Chauhan, Rajinder S.; Kant, Anil

    2015-01-01

    Seabuckthorn is an economically important dioecious plant in which mechanism of sex determination is unknown. The study was conducted to identify seabuckthorn homologous genes involved in floral development which may have role in sex determination. Forty four putative Genes involved in sex determination (GISD) reported in model plants were shortlisted from literature survey, and twenty nine seabuckthorn homologous sequences were identified from available seabuckthorn genomic resources. Of these, 21 genes were found to differentially express in either male or female flower bud stages. HrCRY2 was significantly expressed in female flower buds only while HrCO had significant expression in male flowers only. Among the three male and female floral development stages (FDS), male stage II had significant expression of most of the GISD. Information on these sex-specific expressed genes will help in elucidating sex determination mechanism in seabuckthorn. PMID:25915052

  17. A role for mel-18, a Polycomb group-related vertebrate gene, during theanteroposterior specification of the axial skeleton.

    PubMed

    Akasaka, T; Kanno, M; Balling, R; Mieza, M A; Taniguchi, M; Koseki, H

    1996-05-01

    Segment identity in both invertebrates and vertebrates is conferred by spatially restricted distribution of homeotic gene products. In Drosophila, the expression of Homeobox genes during embryogenesis is initially induced by segmentation gene products and then maintained by Polycomb group and Trithorax group gene products. Polycomb group gene homologs are conserved in vertebrates. Murine mel-18 and closely related bmi-1 are homologous to posterior sex combs and suppressor two of zeste. Mel-18 protein mediates a transcriptional repression via direct binding to specific DNA sequences. To gain further insight into the function of Mel-18, we have inactivated the mel-18 locus by homologous recombination. Mice lacking mel-18 survive to birth and die around 4 weeks after birth after exhibiting strong growth retardation. Similar to the Drosophila posterior sex combs mutant, posterior transformations of the axial skeleton were reproducibly observed in mel-18 mutants. The homeotic transformations were correlated with ectopic expression of Homeobox cluster genes along the anteroposterior axis in the developing paraxial mesoderm. Surprisingly, mel-18-deficient phenotypes are reminiscent of bmi-1 mutants. These results indicate that the vertebrate Polycomb group genes mel-18 and bmi-1, like Drosophila Polycomb group gene products, might play a crucial role in maintaining the silent state of Homeobox gene expression during paraxial mesoderm development.

  18. The seirena B class floral homeotic mutant of California Poppy (Eschscholzia californica) reveals a function of the enigmatic PI motif in the formation of specific multimeric MADS domain protein complexes.

    PubMed

    Lange, Matthias; Orashakova, Svetlana; Lange, Sabrina; Melzer, Rainer; Theißen, Günter; Smyth, David R; Becker, Annette

    2013-02-01

    The products of B class floral homeotic genes specify petal and stamen identity, and loss of B function results in homeotic conversions of petals into sepals and stamens into carpels. Here, we describe the molecular characterization of seirena-1 (sei-1), a mutant from the basal eudicot California poppy (Eschscholzia californica) that shows homeotic changes characteristic of floral homeotic B class mutants. SEI has been previously described as EScaGLO, one of four B class-related MADS box genes in California poppy. The C terminus of SEI, including the highly conserved PI motif, is truncated in sei-1 proteins. Nevertheless, like the wild-type SEI protein, the sei-1 mutant protein is able to bind CArG-boxes and can form homodimers, heterodimers, and several higher order complexes with other MADS domain proteins. However, unlike the wild type, the mutant protein is not able to mediate higher order complexes consisting of specific B, C, and putative E class related proteins likely involved in specifying stamen identity. Within the PI motif, five highly conserved N-terminal amino acids are specifically required for this interaction. Several families lack this short conserved sequence, including the Brassicaceae, and we propose an evolutionary scenario to explain these functional differences.

  19. The seirena B Class Floral Homeotic Mutant of California Poppy (Eschscholzia californica) Reveals a Function of the Enigmatic PI Motif in the Formation of Specific Multimeric MADS Domain Protein Complexes[C][W][OA

    PubMed Central

    Lange, Matthias; Orashakova, Svetlana; Lange, Sabrina; Melzer, Rainer; Theißen, Günter; Smyth, David R.; Becker, Annette

    2013-01-01

    The products of B class floral homeotic genes specify petal and stamen identity, and loss of B function results in homeotic conversions of petals into sepals and stamens into carpels. Here, we describe the molecular characterization of seirena-1 (sei-1), a mutant from the basal eudicot California poppy (Eschscholzia californica) that shows homeotic changes characteristic of floral homeotic B class mutants. SEI has been previously described as EScaGLO, one of four B class–related MADS box genes in California poppy. The C terminus of SEI, including the highly conserved PI motif, is truncated in sei-1 proteins. Nevertheless, like the wild-type SEI protein, the sei-1 mutant protein is able to bind CArG-boxes and can form homodimers, heterodimers, and several higher order complexes with other MADS domain proteins. However, unlike the wild type, the mutant protein is not able to mediate higher order complexes consisting of specific B, C, and putative E class related proteins likely involved in specifying stamen identity. Within the PI motif, five highly conserved N-terminal amino acids are specifically required for this interaction. Several families lack this short conserved sequence, including the Brassicaceae, and we propose an evolutionary scenario to explain these functional differences. PMID:23444328

  20. Temperature, Genes, and Sex: a Comparative View of Sex Determination in Trachemys scripta and Mus musculus

    PubMed Central

    Yao, Humphrey H-C; Capel, Blanche

    2014-01-01

    Sex determination, the step at which differentiation of males and females is initiated in the embryo, is of central importance to the propagation of species. There is a remarkable diversity of mechanisms by which sex determination is accomplished. In general these mechanisms fall into two categories: Genetic Sex Determination (GSD), which depends on genetic differences between the sexes, and Environmental Sex Determination (ESD), which depends on extrinsic cues. In this review we will consider these two means of determining sex with particular emphasis on two species: a species that depends on GSD, Mus musculus, and a species that depends on ESD, Trachemys scripta. Because the structural organization of the adult testis and ovary is very similar across vertebrates, most biologists had expected that the pathways downstream of the sex-determining switch would be conserved. However, emerging data indicate that not only are the initial sex determining mechanisms different, but the downstream pathways and morphogenetic events leading to the development of a testis or ovary also are different. PMID:16046442

  1. Reshaping of global gene expression networks and sex-biased gene expression by integration of a young gene

    PubMed Central

    Chen, Sidi; Ni, Xiaochun; Krinsky, Benjamin H; Zhang, Yong E; Vibranovski, Maria D; White, Kevin P; Long, Manyuan

    2012-01-01

    New genes originate frequently across diverse taxa. Given that genetic networks are typically comprised of robust, co-evolved interactions, the emergence of new genes raises an intriguing question: how do new genes interact with pre-existing genes? Here, we show that a recently originated gene rapidly evolved new gene networks and impacted sex-biased gene expression in Drosophila. This 4–6 million-year-old factor, named Zeus for its role in male fecundity, originated through retroposition of a highly conserved housekeeping gene, Caf40. Zeus acquired male reproductive organ expression patterns and phenotypes. Comparative expression profiling of mutants and closely related species revealed that Zeus has recruited a new set of downstream genes, and shaped the evolution of gene expression in germline. Comparative ChIP-chip revealed that the genomic binding profile of Zeus diverged rapidly from Caf40. These data demonstrate, for the first time, how a new gene quickly evolved novel networks governing essential biological processes at the genomic level. PMID:22543869

  2. Transcriptomic Analysis Implies That GA Regulates Sex Expression via Ethylene-Dependent and Ethylene-Independent Pathways in Cucumber (Cucumis sativus L.)

    PubMed Central

    Zhang, Yan; Zhao, Guiye; Li, Yushun; Mo, Ning; Zhang, Jie; Liang, Yan

    2017-01-01

    Sex differentiation of flower buds is an important developmental process that directly affects fruit yield of cucumber (Cucumis sativus L.). Plant hormones, such as gibberellins (GAs) and ethylene can promote development of male and female flowers, respectively, however, the regulatory mechanisms of GA-induced male flower formation and potential involvement of ethylene in this process still remain unknown. In this study, to unravel the genes and gene networks involved in GA-regulated cucumber sexual development, we performed high throughout RNA-Seq analyses that compared the transcriptomes of shoot tips between GA3 treated and untreated gynoecious cucumber plants. Results showed that GA3 application markedly induced male flowers but decreased ethylene production in shoot tips. Furthermore, the transcript levels of M (CsACS2) gene, ethylene receptor CsETR1 and some ethylene-responsive transcription factors were dramatically changed after GA3 treatment, suggesting a potential involvement of ethylene in GA-regulated sex expression of cucumber. Interestingly, GA3 down-regulated transcript of a C-class floral homeotic gene, CAG2, indicating that GA may also influence cucumber sex determination through an ethylene-independent process. These results suggest a novel model for hormone-mediated sex differentiation and provide a theoretical basis for further dissection of the regulatory mechanism of male flower formation in cucumber. Statement: We reveal that GA can regulate sex expression of cucumber via an ethylene-dependent manner, and the M (CsACS2), CsETR1, and ERFs are probably involved in this process. Moreover, CAG2, a C-class floral homeotic gene, may also participate in GA-modulated cucumber sex determination, but this pathway is ethylene-independent. PMID:28154572

  3. Sex determination in 58 bird species and evaluation of CHD gene as a universal molecular marker in bird sexing.

    PubMed

    Vucicevic, Milos; Stevanov-Pavlovic, Marija; Stevanovic, Jevrosima; Bosnjak, Jasna; Gajic, Bojan; Aleksic, Nevenka; Stanimirovic, Zoran

    2013-01-01

    The aim of this research was to test the CHD gene (Chromo Helicase DNA-binding gene) as a universal molecular marker for sexing birds of relatively distant species. The CHD gene corresponds to the aim because of its high degree of conservation and different lengths in Z and W chromosomes due to different intron sizes. DNA was isolated from feathers and the amplification of the CHD gene was performed with the following sets of polymerase chain reaction (PCR) primers: 2550F/2718R and P2/P8. Sex determination was attempted in 284 samples of 58 bird species. It was successful in 50 bird species; in 16 of those (Alopochen aegyptiacus, Ara severus, Aratinga acuticaudata, Bucorvus leadbeateri, Cereopsis novaehollandiae, Columba arquatrix, Corvus corax, C. frugilegus, Cyanoliseus patagonus, Guttera plumifera, Lamprotornis superbus, Milvus milvus, Neophron percnopterus, Ocyphaps lophotes, Podiceps cristatus, and Poicephalus senegalus), it was carried out for the first time using molecular markers and PCR. It is reasonable to assume that extensive research is necessary to define the CHD gene as a universal molecular marker for successful sex determination in all bird species (with exception of ratites). The results of this study may largely contribute to the aim.

  4. Sex-biased gene expression during head development in a sexually dimorphic stalk-eyed fly.

    PubMed

    Wilkinson, Gerald S; Johns, Philip M; Metheny, Jackie D; Baker, Richard H

    2013-01-01

    Stalk-eyed flies (family Diopsidae) are a model system for studying sexual selection due to the elongated and sexually dimorphic eye-stalks found in many species. These flies are of additional interest because their X chromosome is derived largely from an autosomal arm in other flies. To identify candidate genes required for development of dimorphic eyestalks and investigate how sex-biased expression arose on the novel X, we compared gene expression between males and females using oligonucleotide microarrays and RNA from developing eyestalk tissue or adult heads in the dimorphic diopsid, Teleopsis dalmanni. Microarray analysis revealed sex-biased expression for 26% of 3,748 genes expressed in eye-antennal imaginal discs and concordant sex-biased expression for 86 genes in adult heads. Overall, 415 female-biased and 482 male-biased genes were associated with dimorphic eyestalk development but not differential expression in the adult head. Functional analysis revealed that male-biased genes are disproportionately associated with growth and mitochondrial function while female-biased genes are associated with cell differentiation and patterning or are novel transcripts. With regard to chromosomal effects, dosage compensation occurs by elevated expression of X-linked genes in males. Genes with female-biased expression were more common on the X and less common on autosomes than expected, while male-biased genes exhibited no chromosomal pattern. Rates of protein evolution were lower for female-biased genes but higher for genes that moved on or off the novel X chromosome. These findings cannot be due to meiotic sex chromosome inactivation or by constraints associated with dosage compensation. Instead, they could be consistent with sexual conflict in which female-biased genes on the novel X act primarily to reduce eyespan in females while other genes increase eyespan in both sexes. Additional information on sex-biased gene expression in other tissues and related sexually

  5. Genome-Wide Gene Expression Effects of Sex Chromosome Imprinting in Drosophila

    PubMed Central

    Lemos, Bernardo; Branco, Alan T.; Jiang, Pan-Pan; Hartl, Daniel L.; Meiklejohn, Colin D.

    2013-01-01

    Imprinting is well-documented in both plant and animal species. In Drosophila, the Y chromosome is differently modified when transmitted through the male and female germlines. Here, we report genome-wide gene expression effects resulting from reversed parent-of-origin of the X and Y chromosomes. We found that hundreds of genes are differentially expressed between adult male Drosophila melanogaster that differ in the maternal and paternal origin of the sex chromosomes. Many of the differentially regulated genes are expressed specifically in testis and midgut cells, suggesting that sex chromosome imprinting might globally impact gene expression in these tissues. In contrast, we observed much fewer Y-linked parent-of-origin effects on genome-wide gene expression in females carrying a Y chromosome, indicating that gene expression in females is less sensitive to sex chromosome parent-of-origin. Genes whose expression differs between females inheriting a maternal or paternal Y chromosome also show sex chromosome parent-of-origin effects in males, but the direction of the effects on gene expression (overexpression or underexpression) differ between the sexes. We suggest that passage of sex chromosome chromatin through male meiosis may be required for wild-type function in F1 progeny, whereas disruption of Y-chromosome function through passage in the female germline likely arises because the chromosome is not adapted to the female germline environment. PMID:24318925

  6. Sex-biased gene expression in dioecious garden asparagus (Asparagus officinalis).

    PubMed

    Harkess, Alex; Mercati, Francesco; Shan, Hong-Yan; Sunseri, Francesco; Falavigna, Agostino; Leebens-Mack, Jim

    2015-08-01

    Sex chromosomes have evolved independently in phylogenetically diverse flowering plant lineages. The genes governing sex determination in dioecious species remain unknown, but theory predicts that the linkage of genes influencing male and female function will spur the origin and early evolution of sex chromosomes. For example, in an XY system, the origin of an active Y may be spurred by the linkage of female suppressing and male promoting genes. Garden asparagus (Asparagus officinalis) serves as a model for plant sex chromosome evolution, given that it has recently evolved an XX/XY sex chromosome system. In order to elucidate the molecular basis of gender differences and sex determination, we used RNA-sequencing (RNA-Seq) to identify differentially expressed genes between female (XX), male (XY) and supermale (YY) individuals. We identified 570 differentially expressed genes, and showed that significantly more genes exhibited male-biased than female-biased expression in garden asparagus. In the context of anther development, we identified genes involved in pollen microspore and tapetum development that were specifically expressed in males and supermales. Comparative analysis of genes in the Arabidopsis thaliana, Zea mays and Oryza sativa anther development pathways shows that anther sterility in females probably occurs through interruption of tapetum development before microspore meiosis. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  7. A small molecule screen identifies a novel compound that induces a homeotic transformation in Hydra

    PubMed Central

    Glauber, Kristine M.; Dana, Catherine E.; Park, Steve S.; Colby, David A.; Noro, Yukihiko; Fujisawa, Toshitaka; Chamberlin, A. Richard; Steele, Robert E.

    2013-01-01

    Developmental processes such as morphogenesis, patterning and differentiation are continuously active in the adult Hydra polyp. We carried out a small molecule screen to identify compounds that affect patterning in Hydra. We identified a novel molecule, DAC-2-25, that causes a homeotic transformation of body column into tentacle zone. This transformation occurs in a progressive and polar fashion, beginning at the oral end of the animal. We have identified several strains that respond to DAC-2-25 and one that does not, and we used chimeras from these strains to identify the ectoderm as the target tissue for DAC-2-25. Using transgenic Hydra that express green fluorescent protein under the control of relevant promoters, we examined how DAC-2-25 affects tentacle patterning. Genes whose expression is associated with the tentacle zone are ectopically expressed upon exposure to DAC-2-25, whereas those associated with body column tissue are turned off as the tentacle zone expands. The expression patterns of the organizer-associated gene HyWnt3 and the hypostome-specific gene HyBra2 are unchanged. Structure-activity relationship studies have identified features of DAC-2-25 that are required for activity and potency. This study shows that small molecule screens in Hydra can be used to dissect patterning processes. PMID:24255098

  8. A small molecule screen identifies a novel compound that induces a homeotic transformation in Hydra.

    PubMed

    Glauber, Kristine M; Dana, Catherine E; Park, Steve S; Colby, David A; Noro, Yukihiko; Fujisawa, Toshitaka; Chamberlin, A Richard; Steele, Robert E

    2013-12-01

    Developmental processes such as morphogenesis, patterning and differentiation are continuously active in the adult Hydra polyp. We carried out a small molecule screen to identify compounds that affect patterning in Hydra. We identified a novel molecule, DAC-2-25, that causes a homeotic transformation of body column into tentacle zone. This transformation occurs in a progressive and polar fashion, beginning at the oral end of the animal. We have identified several strains that respond to DAC-2-25 and one that does not, and we used chimeras from these strains to identify the ectoderm as the target tissue for DAC-2-25. Using transgenic Hydra that express green fluorescent protein under the control of relevant promoters, we examined how DAC-2-25 affects tentacle patterning. Genes whose expression is associated with the tentacle zone are ectopically expressed upon exposure to DAC-2-25, whereas those associated with body column tissue are turned off as the tentacle zone expands. The expression patterns of the organizer-associated gene HyWnt3 and the hypostome-specific gene HyBra2 are unchanged. Structure-activity relationship studies have identified features of DAC-2-25 that are required for activity and potency. This study shows that small molecule screens in Hydra can be used to dissect patterning processes.

  9. Analysis of the Tribolium homeotic complex: insights into mechanisms constraining insect Hox clusters.

    PubMed

    Shippy, Teresa D; Ronshaugen, Matthew; Cande, Jessica; He, Jianping; Beeman, Richard W; Levine, Michael; Brown, Susan J; Denell, Robin E

    2008-04-01

    The remarkable conservation of Hox clusters is an accepted but little understood principle of biology. Some organizational constraints have been identified for vertebrate Hox clusters, but most of these are thought to be recent innovations that may not apply to other organisms. Ironically, many model organisms have disrupted Hox clusters and may not be well-suited for studies of structural constraints. In contrast, the red flour beetle, Tribolium castaneum, which has a long history in Hox gene research, is thought to have a more ancestral-type Hox cluster organization. Here, we demonstrate that the Tribolium homeotic complex (HOMC) is indeed intact, with the individual Hox genes in the expected colinear arrangement and transcribed from the same strand. There is no evidence that the cluster has been invaded by non-Hox protein-coding genes, although expressed sequence tag and genome tiling data suggest that noncoding transcripts are prevalent. Finally, our analysis of several mutations affecting the Tribolium HOMC suggests that intermingling of enhancer elements with neighboring transcription units may constrain the structure of at least one region of the Tribolium cluster. This work lays a foundation for future studies of the Tribolium HOMC that may provide insights into the reasons for Hox cluster conservation.

  10. Analysis of the Tribolium homeotic complex: insights into mechanisms constraining insect Hox clusters

    PubMed Central

    Ronshaugen, Matthew; Cande, Jessica; He, JianPing; Beeman, Richard W.; Levine, Michael; Brown, Susan J.; Denell, Robin E.

    2008-01-01

    The remarkable conservation of Hox clusters is an accepted but little understood principle of biology. Some organizational constraints have been identified for vertebrate Hox clusters, but most of these are thought to be recent innovations that may not apply to other organisms. Ironically, many model organisms have disrupted Hox clusters and may not be well-suited for studies of structural constraints. In contrast, the red flour beetle, Tribolium castaneum, which has a long history in Hox gene research, is thought to have a more ancestral-type Hox cluster organization. Here, we demonstrate that the Tribolium homeotic complex (HOMC) is indeed intact, with the individual Hox genes in the expected colinear arrangement and transcribed from the same strand. There is no evidence that the cluster has been invaded by non-Hox protein-coding genes, although expressed sequence tag and genome tiling data suggest that noncoding transcripts are prevalent. Finally, our analysis of several mutations affecting the Tribolium HOMC suggests that intermingling of enhancer elements with neighboring transcription units may constrain the structure of at least one region of the Tribolium cluster. This work lays a foundation for future studies of the Tribolium HOMC that may provide insights into the reasons for Hox cluster conservation. PMID:18392875

  11. Assessment of Gene-by-Sex Interaction Effect on Bone Mineral Density

    PubMed Central

    Liu, Ching-Ti; Estrada, Karol; Yerges-Armstrong, Laura M.; Amin, Najaf; Evangelou, Evangelos; Li, Guo; Minster, Ryan L.; Carless, Melanie A.; Kammerer, Candace M.; Oei, Ling; Zhou, Yanhua; Alonso, Nerea; Dailiana, Zoe; Eriksson, Joel; García-Giralt, Natalia; Giroux, Sylvie; Husted, Lise Bjerre; Khusainova, Rita I.; Koromila, Theodora; Kung, Annie WaiChee; Lewis, Joshua R.; Masi, Laura; Mencej-Bedrac, Simona; Nogues, Xavier; Patel, Millan S.; Prezelj, Janez; Richards, J Brent; Sham, Pak Chung; Spector, Timothy; Vandenput, Liesbeth; Xiao, Su-Mei; Zheng, Hou-Feng; Zhu, Kun; Balcells, Susana; Brandi, Maria Luisa; Frost, Morten; Goltzman, David; González-Macías, Jesús; Karlsson, Magnus; Khusnutdinova, Elza K.; Kollia, Panagoula; Langdahl, Bente Lomholt; Ljunggren, Östen; Lorentzon, Mattias; Marc, Janja; Mellström, Dan; Ohlsson, Claes; Olmos, José M.; Ralston, Stuart H.; Riancho, José A.; Rousseau, François; Urreizti, Roser; Van Hul, Wim; Zarrabeitia, María T.; Castano-Betancourt, Martha; Demissie, Serkalem; Grundberg, Elin; Herrera, Lizbeth; Kwan, Tony; Medina-Gómez, Carolina; Pastinen, Tomi; Sigurdsson, Gunnar; Thorleifsson, Gudmar; vanMeurs, Joyce B.J.; Blangero, John; Hofman, Albert; Liu, Yongmei; Mitchell, Braxton D.; O’Connell, Jeffrey R.; Oostra, Ben A.; Rotter, Jerome I; Stefansson, Kari; Streeten, Elizabeth A.; Styrkarsdottir, Unnur; Thorsteinsdottir, Unnur; Tylavsky, Frances A.; Uitterlinden, Andre; Cauley, Jane A.; Harris, Tamara B.; Ioannidis, John P.A.; Psaty, Bruce M.; Robbins, John A; Zillikens, M. Carola; vanDuijn, Cornelia M.; Prince, Richard L.; Karasik, David; Rivadeneira, Fernando; Kiel, Douglas P.; Cupples, L. Adrienne; Hsu, Yi-Hsiang

    2012-01-01

    Background Sexual dimorphism in various bone phenotypes, including bone mineral density (BMD), is widely observed; however the extent to which genes explain these sex differences is unclear. To identify variants with different effects by sex, we examined gene-by-sex autosomal interactions genome-wide, and performed eQTL analysis and bioinformatics network analysis. Methods We conducted an autosomal genome-wide meta-analysis of gene-by-sex interaction on lumbar spine (LS-) and femoral neck (FN-) BMD, in 25,353 individuals from eight cohorts. In a second stage, we followed up the 12 top SNPs (P<1×10−5) in an additional set of 24,763 individuals. Gene-by-sex interaction and sex-specific effects were examined in these 12 SNPs. Results We detected one novel genome-wide significant interaction associated with LS-BMD at the Chr3p26.1-p25.1 locus, near the GRM7 gene (male effect = 0.02 & p-value = 3.0×10−5; female effect = −0.007 & p-value=3.3×10−2) and eleven suggestive loci associated with either FN- or LS-BMD in discovery cohorts. However, there was no evidence for genome-wide significant (P<5×10−8) gene-by-sex interaction in the joint analysis of discovery and replication cohorts. Conclusion Despite the large collaborative effort, no genome-wide significant evidence for gene-by-sex interaction was found influencing BMD variation in this screen of autosomal markers. If they exist, gene-by-sex interactions for BMD probably have weak effects, accounting for less than 0.08% of the variation in these traits per implicated SNP. PMID:22692763

  12. Function and evolution of sex determination mechanisms, genes and pathways in insects

    PubMed Central

    Gempe, Tanja; Beye, Martin

    2011-01-01

    Animals have evolved a bewildering diversity of mechanisms to determine the two sexes. Studies of sex determination genes – their history and function – in non-model insects and Drosophila have allowed us to begin to understand the generation of sex determination diversity. One common theme from these studies is that evolved mechanisms produce activities in either males or females to control a shared gene switch that regulates sexual development. Only a few small-scale changes in existing and duplicated genes are sufficient to generate large differences in sex determination systems. This review summarises recent findings in insects, surveys evidence of how and why sex determination mechanisms can change rapidly and suggests fruitful areas of future research. PMID:21110346

  13. Sex differences in carbohydrate metabolism are linked to gene expression in Caenorhabditis elegans.

    PubMed

    Miersch, Claudia; Döring, Frank

    2012-01-01

    The male and the hermaphrodite forms of the nematode Caenorhabditis elegans (C. elegans) differ markedly in anatomy, nervous system and behavior at adulthood. Using the male mutants fog-2, him-5, and him-8, we compared body proportions and composition, and aspects of carbohydrate metabolism and gene expression between the C. elegans sexes in three adult stages. In all experiments, both sexes were grown on the same plate and separated using flow cytometry. The fat to fat-free mass ratio and the body volume-adjusted fat mass is similar between the sexes, although the body size is more than 50% smaller in adult males than in age-matched hermaphrodites. The volume-adjusted total RNA content is approximately 2-fold lower in males. Biochemical and NMR-based analyses reveal higher trehalose levels and much lower glucose levels in males than in hermaphrodites. The resulting trehalose-to-glucose ratio is 5.4-fold higher in males. These sex differences are reflected in gene expression data because the genes encoding key enzymes of the glycolysis and trehalose synthesis pathways are more highly expressed in males than in hermaphrodites. Notably, expression of the phosphofructokinase gene (C50F4.2) is 29-fold higher in males. Comparative analysis of gene expression data identifies 285 male-specific and 160 hermaphrodite-specific genes. These include transcription factor and C-type lectin-encoding genes. More than 35% of all C-type lectin genes are more highly expressed in males. The expression of many C-type lectin genes differs by a factor of >100 between the sexes. In conclusion, we found sex differences in carbohydrate metabolism that are linked to gene expression and identified certain lectin genes that are differentially expressed by the C. elegans sexes.

  14. Sex Differences in Carbohydrate Metabolism Are Linked to Gene Expression in Caenorhabditis elegans

    PubMed Central

    Miersch, Claudia; Döring, Frank

    2012-01-01

    The male and the hermaphrodite forms of the nematode Caenorhabditis elegans (C. elegans) differ markedly in anatomy, nervous system and behavior at adulthood. Using the male mutants fog-2, him-5, and him-8, we compared body proportions and composition, and aspects of carbohydrate metabolism and gene expression between the C. elegans sexes in three adult stages. In all experiments, both sexes were grown on the same plate and separated using flow cytometry. The fat to fat-free mass ratio and the body volume-adjusted fat mass is similar between the sexes, although the body size is more than 50% smaller in adult males than in age-matched hermaphrodites. The volume-adjusted total RNA content is approximately 2-fold lower in males. Biochemical and NMR-based analyses reveal higher trehalose levels and much lower glucose levels in males than in hermaphrodites. The resulting trehalose-to-glucose ratio is 5.4-fold higher in males. These sex differences are reflected in gene expression data because the genes encoding key enzymes of the glycolysis and trehalose synthesis pathways are more highly expressed in males than in hermaphrodites. Notably, expression of the phosphofructokinase gene (C50F4.2) is 29-fold higher in males. Comparative analysis of gene expression data identifies 285 male-specific and 160 hermaphrodite-specific genes. These include transcription factor and C-type lectin-encoding genes. More than 35% of all C-type lectin genes are more highly expressed in males. The expression of many C-type lectin genes differs by a factor of >100 between the sexes. In conclusion, we found sex differences in carbohydrate metabolism that are linked to gene expression and identified certain lectin genes that are differentially expressed by the C. elegans sexes. PMID:22984551

  15. Identification and Expression Profiles of Sex Pheromone Biosynthesis and Transport Related Genes in Spodoptera litura

    PubMed Central

    Zhang, Ya-Nan; Zhu, Xiu-Yun; Fang, Li-Ping; He, Peng; Wang, Zhi-Qiang; Chen, Geng; Sun, Liang; Ye, Zhan-Feng; Deng, Dao-Gui; Li, Jin-Bu

    2015-01-01

    Although the general pathway of sex pheromone synthesis in moth species has been established, the molecular mechanisms remain poorly understood. The common cutworm Spodoptera litura is an important agricultural pest worldwide and causes huge economic losses annually. The female sex pheromone of S. litura comprises Z9,E11-14:OAc, Z9,E12-14:OAc, Z9-14:OAc, and E11-14:OAc. By sequencing and analyzing the transcriptomic data of the sex pheromone glands, we identified 94 candidate genes related to pheromone biosynthesis (55 genes) or chemoreception (39 genes). Gene expression patterns and phylogenetic analysis revealed that two desaturase genes (SlitDes5 and SlitDes11) and one fatty acyl reductase gene (SlitFAR3) showed pheromone gland (PG) biased or specific expression, and clustered with genes known to be involved in pheromone synthesis in other moth species. Furthermore, 4 chemoreception related genes (SlitOBP6, SlitOBP11, SlitCSP3, and SlitCSP14) also showed higher expression in the PG, and could be additional candidate genes involved in sex pheromone transport. This study provides the first solid background information that should facilitate further elucidation of sex pheromone biosynthesis and transport, and indicates potential targets to disrupt sexual communication in S. litura for a novel pest management strategy. PMID:26445454

  16. Identification and Expression Profiles of Sex Pheromone Biosynthesis and Transport Related Genes in Spodoptera litura.

    PubMed

    Zhang, Ya-Nan; Zhu, Xiu-Yun; Fang, Li-Ping; He, Peng; Wang, Zhi-Qiang; Chen, Geng; Sun, Liang; Ye, Zhan-Feng; Deng, Dao-Gui; Li, Jin-Bu

    2015-01-01

    Although the general pathway of sex pheromone synthesis in moth species has been established, the molecular mechanisms remain poorly understood. The common cutworm Spodoptera litura is an important agricultural pest worldwide and causes huge economic losses annually. The female sex pheromone of S. litura comprises Z9,E11-14:OAc, Z9,E12-14:OAc, Z9-14:OAc, and E11-14:OAc. By sequencing and analyzing the transcriptomic data of the sex pheromone glands, we identified 94 candidate genes related to pheromone biosynthesis (55 genes) or chemoreception (39 genes). Gene expression patterns and phylogenetic analysis revealed that two desaturase genes (SlitDes5 and SlitDes11) and one fatty acyl reductase gene (SlitFAR3) showed pheromone gland (PG) biased or specific expression, and clustered with genes known to be involved in pheromone synthesis in other moth species. Furthermore, 4 chemoreception related genes (SlitOBP6, SlitOBP11, SlitCSP3, and SlitCSP14) also showed higher expression in the PG, and could be additional candidate genes involved in sex pheromone transport. This study provides the first solid background information that should facilitate further elucidation of sex pheromone biosynthesis and transport, and indicates potential targets to disrupt sexual communication in S. litura for a novel pest management strategy.

  17. Independent Evolutionary Origin of fem Paralogous Genes and Complementary Sex Determination in Hymenopteran Insects

    PubMed Central

    Koch, Vasco; Nissen, Inga; Schmitt, Björn D.; Beye, Martin

    2014-01-01

    The primary signal of sex determination in the honeybee, the complementary sex determiner (csd) gene, evolved from a gene duplication event from an ancestral copy of the fem gene. Recently, other paralogs of the fem gene have been identified in several ant and bumblebee genomes. This discovery and the close phylogenetic relationship of the paralogous gene sequences led to the hypothesis of a single ancestry of the csd genetic system of complementary sex determination in the Hymenopteran insects, in which the fem and csd gene copies evolved as a unit in concert with the mutual transfers of sequences (concerted evolution). Here, we show that the paralogous gene copies evolved repeatedly through independent gene duplication events in the honeybee, bumblebee, and ant lineage. We detected no sequence tracts that would indicate a DNA transfer between the fem and the fem1/csd genes between different ant and bee species. Instead, we found tracts of duplication events in other genomic locations, suggesting that gene duplication was a frequent event in the evolution of these genes. These and other evidences suggest that the fem1/csd gene originated repeatedly through gene duplications in the bumblebee, honeybee, and ant lineages in the last 100 million years. Signatures of concerted evolution were not detectable, implicating that the gene tree based on neutral synonymous sites represents the phylogenetic relationships and origins of the fem and fem1/csd genes. Our results further imply that the fem1 and csd gene in bumblebees, honeybees, and ants are not orthologs, because they originated independently from the fem gene. Hence, the widely shared and conserved complementary sex determination mechanism in Hymenopteran insects is controlled by different genes and molecular processes. These findings highlight the limits of comparative genomics and emphasize the requirement to study gene functions in different species and major hymenopteran lineages. PMID:24743790

  18. Independent evolutionary origin of fem paralogous genes and complementary sex determination in hymenopteran insects.

    PubMed

    Koch, Vasco; Nissen, Inga; Schmitt, Björn D; Beye, Martin

    2014-01-01

    The primary signal of sex determination in the honeybee, the complementary sex determiner (csd) gene, evolved from a gene duplication event from an ancestral copy of the fem gene. Recently, other paralogs of the fem gene have been identified in several ant and bumblebee genomes. This discovery and the close phylogenetic relationship of the paralogous gene sequences led to the hypothesis of a single ancestry of the csd genetic system of complementary sex determination in the Hymenopteran insects, in which the fem and csd gene copies evolved as a unit in concert with the mutual transfers of sequences (concerted evolution). Here, we show that the paralogous gene copies evolved repeatedly through independent gene duplication events in the honeybee, bumblebee, and ant lineage. We detected no sequence tracts that would indicate a DNA transfer between the fem and the fem1/csd genes between different ant and bee species. Instead, we found tracts of duplication events in other genomic locations, suggesting that gene duplication was a frequent event in the evolution of these genes. These and other evidences suggest that the fem1/csd gene originated repeatedly through gene duplications in the bumblebee, honeybee, and ant lineages in the last 100 million years. Signatures of concerted evolution were not detectable, implicating that the gene tree based on neutral synonymous sites represents the phylogenetic relationships and origins of the fem and fem1/csd genes. Our results further imply that the fem1 and csd gene in bumblebees, honeybees, and ants are not orthologs, because they originated independently from the fem gene. Hence, the widely shared and conserved complementary sex determination mechanism in Hymenopteran insects is controlled by different genes and molecular processes. These findings highlight the limits of comparative genomics and emphasize the requirement to study gene functions in different species and major hymenopteran lineages.

  19. Transcription of the sex-determining region genes Sry and Zfy in the mouse preimplantation embryo.

    PubMed Central

    Zwingman, T; Erickson, R P; Boyer, T; Ao, A

    1993-01-01

    We have confirmed the faster growth of male preimplantation mouse embryos. We have also studied the transcription of Y chromosomal genes postulated to have a role in sex determination, using the highly sensitive technique of reverse-transcription polymerase chain reaction at these early stages. We find that two sex-determining region genes, Sry and Zfy, are transcribed during mouse preimplantation development, while the Zfy homologs Zfx and Zfa and a sex-determining region gene originally called A1s9 (now called Ube1y-1) are not. We also show that the anti-Müllerian hormone gene, which contains a Sry consensus binding element in its 5' promoter region, is not transcribed at this time. Developmental curves show that Sry and Zfy are expressed commencing at the two-cell stage. These results suggest that mammalian sex determination starts prior to gonad differentiation. Images PMID:8430091

  20. Transcription of the sex-determining region genes Sry and Zfy in the mouse preimplantation embryo.

    PubMed

    Zwingman, T; Erickson, R P; Boyer, T; Ao, A

    1993-02-01

    We have confirmed the faster growth of male preimplantation mouse embryos. We have also studied the transcription of Y chromosomal genes postulated to have a role in sex determination, using the highly sensitive technique of reverse-transcription polymerase chain reaction at these early stages. We find that two sex-determining region genes, Sry and Zfy, are transcribed during mouse preimplantation development, while the Zfy homologs Zfx and Zfa and a sex-determining region gene originally called A1s9 (now called Ube1y-1) are not. We also show that the anti-Müllerian hormone gene, which contains a Sry consensus binding element in its 5' promoter region, is not transcribed at this time. Developmental curves show that Sry and Zfy are expressed commencing at the two-cell stage. These results suggest that mammalian sex determination starts prior to gonad differentiation.

  1. Sex chromosome loss and the pseudoautosomal region genes in hematological malignancies

    PubMed Central

    Weng, Stephanie; Stoner, Samuel A.; Zhang, Dong-Er

    2016-01-01

    Cytogenetic aberrations, such as chromosomal translocations, aneuploidy, and amplifications, are frequently detected in hematological malignancies. For many of the common autosomal aberrations, the mechanisms underlying their roles in cancer development have been well-characterized. On the contrary, although loss of a sex chromosome is observed in a broad range of hematological malignancies, how it cooperates in disease development is less understood. Nevertheless, it has been postulated that tumor suppressor genes reside on the sex chromosomes. Although the X and Y sex chromosomes are highly divergent, the pseudoautosomal regions are homologous between both chromosomes. Here, we review what is currently known about the pseudoautosomal region genes in the hematological system. Additionally, we discuss implications for haploinsufficiency of critical pseudoautosomal region sex chromosome genes, driven by sex chromosome loss, in promoting hematological malignancies. Because mechanistic studies on disease development rely heavily on murine models, we also discuss the challenges and caveats of existing models, and propose alternatives for examining the involvement of pseudoautosomal region genes and loss of a sex chromosome in vivo. With the widespread detection of loss of a sex chromosome in different hematological malignances, the elucidation of the role of pseudoautosomal region genes in the development and progression of these diseases would be invaluable to the field. PMID:27655702

  2. Genes and sex hormones interaction in neurodevelopmental disorders.

    PubMed

    Romano, Emilia; Cosentino, Livia; Laviola, Giovanni; De Filippis, Bianca

    2016-08-01

    The prevalence, age of onset and symptomatology of many neurodevelopmental disorders strongly differ between genders. This review examines sex biases in human neurodevelopmental disorders and in validated animal models. A focus is made on disorders of well-established genetic origin, such as Rett syndrome, CDKL5-associated disorders, Fragile X and Down syndrome. Autism is also addressed, given its paradigmatic role as a sex-biased neurodevelopmental disorder. Reviewed literature confirms that a complex interaction between genetic factors and sex hormones may underlie the differential susceptibility of genders and may impact the severity of symptoms in most of the analyzed neurodevelopmental disorders. Even though further studies addressing the advantages and disadvantages conferred by biological sex in this class of disorders are needed to disentangle the underlying mechanisms, present findings suggest that modulation of sex steroid-related pathways may represent an innovative approach for these diseases. Much effort is now expected to unravel the potential therapeutic efficacy of drugs targeting sex hormones-related signaling pathways in neurodevelopmental disorders of well-established genetic origin. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Sex as a response to oxidative stress: a twofold increase in cellular reactive oxygen species activates sex genes.

    PubMed

    Nedelcu, Aurora M; Marcu, Oana; Michod, Richard E

    2004-08-07

    Organisms are constantly subjected to factors that can alter the cellular redox balance and result in the formation of a series of highly reactive molecules known as reactive oxygen species (ROS). As ROS can be damaging to biological structures, cells evolved a series of mechanisms (e.g. cell-cycle arrest, programmed cell death) to respond to high levels of ROS (i.e. oxidative stress). Recently, we presented evidence that in a facultatively sexual lineage--the multicellular green alga Volvox carteri--sex is an additional response to increased levels of stress, and probably ROS and DNA damage. Here we show that, in V. carteri, (i) sex is triggered by an approximately twofold increase in the level of cellular ROS (induced either by the natural sex-inducing stress, namely heat, or by blocking the mitochondrial electron transport chain with antimycin A), and (ii) ROS are responsible for the activation of sex genes. As most types of stress result in the overproduction of ROS, we believe that our findings will prove to extend to other facultatively sexual lineages, which could be indicative of the ancestral role of sex as an adaptive response to stress and ROS-induced DNA damage.

  4. Chromosome-wide mechanisms to decouple gene expression from gene dose during sex-chromosome evolution

    PubMed Central

    Wheeler, Bayly S; Anderson, Erika; Frøkjær-Jensen, Christian; Bian, Qian; Jorgensen, Erik; Meyer, Barbara J

    2016-01-01

    Changes in chromosome number impair fitness by disrupting the balance of gene expression. Here we analyze mechanisms to compensate for changes in gene dose that accompanied the evolution of sex chromosomes from autosomes. Using single-copy transgenes integrated throughout the Caenorhabditis elegans genome, we show that expression of all X-linked transgenes is balanced between XX hermaphrodites and XO males. However, proximity of a dosage compensation complex (DCC) binding site (rex site) is neither necessary to repress X-linked transgenes nor sufficient to repress transgenes on autosomes. Thus, X is broadly permissive for dosage compensation, and the DCC acts via a chromosome-wide mechanism to balance transcription between sexes. In contrast, no analogous X-chromosome-wide mechanism balances transcription between X and autosomes: expression of compensated hermaphrodite X-linked transgenes is half that of autosomal transgenes. Furthermore, our results argue against an X-chromosome dosage compensation model contingent upon rex-directed positioning of X relative to the nuclear periphery. DOI: http://dx.doi.org/10.7554/eLife.17365.001 PMID:27572259

  5. Identification of internal reference genes for gene expression normalization between the two sexes in dioecious white Campion.

    PubMed

    Zemp, Niklaus; Minder, Aria; Widmer, Alex

    2014-01-01

    Quantitative real time (qRT)-PCR is a precise and efficient method for studying gene expression changes between two states of interest, and is frequently used for validating interesting gene expression patterns in candidate genes initially identified in genome-wide expression analyses, such as RNA-seq experiments. For an adequate normalisation of qRT-PCR data, it is essential to have reference genes available whose expression intensities are constant among the different states of interest. In this study we present and validate a catalogue of traditional and newly identified reference genes that were selected from RNA-seq data from multiple individuals from the dioecious plant Silene latifolia with the aim of studying gene expression differences between the two sexes in both reproductive and vegetative tissues. The catalogue contains more than 15 reference genes with both stable expression intensities and a range of expression intensities in flower buds and leaf tissues. These reference genes were used to normalize expression differences between reproductive and vegetative tissues in eight candidate genes with sex-biased expression. Our results suggest a trend towards a reduced sex-bias in sex-linked gene expression in vegetative tissues. In this study, we report on the systematic identification and validation of internal reference genes for adequate normalization of qRT-PCR-based analyses of gene expression differences between the two sexes in S. latifolia. We also show how RNA-seq data can be used efficiently to identify suitable reference genes in a wide diversity of species.

  6. Recognition of floral homeotic MADS domain transcription factors by a phytoplasmal effector, phyllogen, induces phyllody

    PubMed Central

    Maejima, Kensaku; Iwai, Ryo; Himeno, Misako; Komatsu, Ken; Kitazawa, Yugo; Fujita, Naoko; Ishikawa, Kazuya; Fukuoka, Misato; Minato, Nami; Yamaji, Yasuyuki; Oshima, Kenro; Namba, Shigetou

    2014-01-01

    Plant pathogens alter the course of plant developmental processes, resulting in abnormal morphology in infected host plants. Phytoplasmas are unique plant-pathogenic bacteria that transform plant floral organs into leaf-like structures and cause the emergence of secondary flowers. These distinctive symptoms have attracted considerable interest for many years. Here, we revealed the molecular mechanisms of the floral symptoms by focusing on a phytoplasma-secreted protein, PHYL1, which induces morphological changes in flowers that are similar to those seen in phytoplasma-infected plants. PHYL1 is a homolog of the phytoplasmal effector SAP54 that also alters floral development. Using yeast two-hybrid and in planta transient co-expression assays, we found that PHYL1 interacts with and degrades the floral homeotic MADS domain proteins SEPALLATA3 (SEP3), APETALA1 (AP1) and CAULIFLOWER (CAL). This degradation of MADS domain proteins was dependent on the ubiquitin–proteasome pathway. The expression of floral development genes downstream of SEP3 and AP1 was disrupted in 35S::PHYL1 transgenic plants. PHYL1 was genetically and functionally conserved among other phytoplasma strains and species. We designate PHYL1, SAP54 and their homologs as members of the phyllody-inducing gene family of ‘phyllogens’. PMID:24597566

  7. Recognition of floral homeotic MADS domain transcription factors by a phytoplasmal effector, phyllogen, induces phyllody.

    PubMed

    Maejima, Kensaku; Iwai, Ryo; Himeno, Misako; Komatsu, Ken; Kitazawa, Yugo; Fujita, Naoko; Ishikawa, Kazuya; Fukuoka, Misato; Minato, Nami; Yamaji, Yasuyuki; Oshima, Kenro; Namba, Shigetou

    2014-05-01

    Plant pathogens alter the course of plant developmental processes, resulting in abnormal morphology in infected host plants. Phytoplasmas are unique plant-pathogenic bacteria that transform plant floral organs into leaf-like structures and cause the emergence of secondary flowers. These distinctive symptoms have attracted considerable interest for many years. Here, we revealed the molecular mechanisms of the floral symptoms by focusing on a phytoplasma-secreted protein, PHYL1, which induces morphological changes in flowers that are similar to those seen in phytoplasma-infected plants. PHYL1 is a homolog of the phytoplasmal effector SAP54 that also alters floral development. Using yeast two-hybrid and in planta transient co-expression assays, we found that PHYL1 interacts with and degrades the floral homeotic MADS domain proteins SEPALLATA3 (SEP3), APETALA1 (AP1) and CAULIFLOWER (CAL). This degradation of MADS domain proteins was dependent on the ubiquitin-proteasome pathway. The expression of floral development genes downstream of SEP3 and AP1 was disrupted in 35S::PHYL1 transgenic plants. PHYL1 was genetically and functionally conserved among other phytoplasma strains and species. We designate PHYL1, SAP54 and their homologs as members of the phyllody-inducing gene family of 'phyllogens'. © 2014 The Authors.The Plant Journal published by Society for Experimental Biology and John Wiley & Sons Ltd.

  8. Gender-specific gene expression in post-mortem human brain: localization to sex chromosomes.

    PubMed

    Vawter, Marquis P; Evans, Simon; Choudary, Prabhakara; Tomita, Hiroaki; Meador-Woodruff, Jim; Molnar, Margherita; Li, Jun; Lopez, Juan F; Myers, Rick; Cox, David; Watson, Stanley J; Akil, Huda; Jones, Edward G; Bunney, William E

    2004-02-01

    Gender differences in brain development and in the prevalence of neuropsychiatric disorders such as depression have been reported. Gender differences in human brain might be related to patterns of gene expression. Microarray technology is one useful method for investigation of gene expression in brain. We investigated gene expression, cell types, and regional expression patterns of differentially expressed sex chromosome genes in brain. We profiled gene expression in male and female dorsolateral prefrontal cortex, anterior cingulate cortex, and cerebellum using the Affymetrix oligonucleotide microarray platform. Differentially expressed genes between males and females on the Y chromosome (DBY, SMCY, UTY, RPS4Y, and USP9Y) and X chromosome (XIST) were confirmed using real-time PCR measurements. In situ hybridization confirmed the differential expression of gender-specific genes and neuronal expression of XIST, RPS4Y, SMCY, and UTY in three brain regions examined. The XIST gene, which silences gene expression on regions of the X chromosome, is expressed in a subset of neurons. Since a subset of neurons express gender-specific genes, neural subpopulations may exhibit a subtle sexual dimorphism at the level of differences in gene regulation and function. The distinctive pattern of neuronal expression of XIST, RPS4Y, SMCY, and UTY and other sex chromosome genes in neuronal subpopulations may possibly contribute to gender differences in prevalence noted for some neuropsychiatric disorders. Studies of the protein expression of these sex-chromosome-linked genes in brain tissue are required to address the functional consequences of the observed gene expression differences.

  9. Is a sex-determining gene(s) necessary for sex-determination in amphibians? Steroid hormones may be the key factor.

    PubMed

    Nakamura, M

    2013-01-01

    Amphibians have 2 genetic sex-determining systems, one with male (XX/XY) and one with female (ZZ/ZW) heterogamety. While the ancestral state of sex-determination is thought to be female heterogamety, male and female heterogametic types were probably once interchangeable. The Japanese frog Rana rugosa has both XX/XY and ZZ/ZW systems within a single species in certain local populations. However, steroid hormones can alter the phenotypic sex epigenetically. In R. rugosa, steroidogenic enzyme expression starts before sex-determination in the indifferent gonad, and these enzymes become active in both male and female tadpoles. Androgens are produced in the indifferent gonad of male tadpoles at high levels, whereas estrogens are synthesized in females. In this regard, the observed enhanced expression of the hormone-metabolizing genes, CYP19 in the female gonad and CYP17 in males, may be crucial for sex-determination. Moreover, with FSH known to increase estrogen synthesis in the vertebrate ovary, observed upregulation of FSH receptor (FSHR) expression in the indifferent gonad of female tadpoles is intriguing. These data suggest that steroid hormones could be crucial for sex-determination in R. rugosa, with the consequence that upregulation of CYP19 and FSHR expression is necessary for female and CYP17 for male sex-determination.

  10. Interactions of the Tribolium Sex combs reduced and proboscipedia orthologs in embryonic labial development.

    PubMed Central

    DeCamillis, M A; Lewis, D L; Brown, S J; Beeman, R W; Denell, R E

    2001-01-01

    The role of Hox genes in the development of insect gnathal appendages has been examined in three insects: the fruitfly, Drosophila melanogaster; the milkweed bug, Oncopeltus fasciatus; and the red flour beetle, Tribolium castaneum. In each of these organisms, the identity of the labium depends on the homeotic genes Sex combs reduced (Scr) and proboscipedia (pb). Loss of pb function in each of the three insects results in homeotic transformation of the labial appendages to legs. In contrast, loss of Scr function yields a different transformation in each species. Interestingly, mutations in Cephalothorax (Cx), the Tribolium ortholog of Scr, transform the labial appendages to antennae, a result seen in the other insects only when both pb and Scr are removed. We show here that the Tribolium labial appendages also develop as antennae in double mutants. Further, we demonstrate that expression of the Tribolium proboscipedia ortholog maxillopedia (mxp) is greatly reduced or absent in the labium of Cx mutant larvae. Thus, in the wild-type labial segment, Cx function is required (directly or indirectly) for mxp transcription. A similar interaction between Scr and pb during Drosophila embryogenesis has been described recently. Thus, this regulatory paradigm appears to be conserved at least within the Holometabola. PMID:11779803

  11. Evolutionary conservation and predicted structure of the Drosophila extra sex combs repressor protein.

    PubMed Central

    Ng, J; Li, R; Morgan, K; Simon, J

    1997-01-01

    The Drosophila extra sex combs (esc) protein, a member of the Polycomb group (PcG), is a transcriptional repressor of homeotic genes. Genetic studies have shown that esc protein is required in early embryos at about the time that other PcG proteins become engaged in homeotic gene repression. The esc protein consists primarily of multiple copies of the WD repeat, a motif that has been implicated in protein-protein interaction. To further investigate the domain organization of esc protein, we have isolated and characterized esc homologs from divergent insect species. We report that esc protein is highly conserved in housefly (72% identical to Drosophila esc), butterfly (55% identical), and grasshopper (56% identical). We show that the butterfly homolog provides esc function in Drosophila, indicating that the sequence similarities reflect functional conservation. Homology modeling using the crystal structure of another WD repeat protein, the G-protein beta-subunit, predicts that esc protein adopts a beta-propeller structure. The sequence comparisons and modeling suggest that there are seven WD repeats in esc protein which together form a seven-bladed beta-propeller. We locate the conserved regions in esc protein with respect to this predicted structure. Site-directed mutagenesis of specific loops, predicted to extend from the propeller surface, identifies conserved parts of esc protein required for function in vivo. We suggest that these regions might mediate physical interaction with esc partner proteins. PMID:9343430

  12. Identification of SOX3 as an XX male sex reversal gene in mice and humans

    PubMed Central

    Sutton, Edwina; Hughes, James; White, Stefan; Sekido, Ryohei; Tan, Jacqueline; Arboleda, Valerie; Rogers, Nicholas; Knower, Kevin; Rowley, Lynn; Eyre, Helen; Rizzoti, Karine; McAninch, Dale; Goncalves, Joao; Slee, Jennie; Turbitt, Erin; Bruno, Damien; Bengtsson, Henrik; Harley, Vincent; Vilain, Eric; Sinclair, Andrew; Lovell-Badge, Robin; Thomas, Paul

    2010-01-01

    Sex in mammals is genetically determined and is defined at the cellular level by sex chromosome complement (XY males and XX females). The Y chromosome–linked gene sex-determining region Y (SRY) is believed to be the master initiator of male sex determination in almost all eutherian and metatherian mammals, functioning to upregulate expression of its direct target gene Sry-related HMG box–containing gene 9 (SOX9). Data suggest that SRY evolved from SOX3, although there is no direct functional evidence to support this hypothesis. Indeed, loss-of-function mutations in SOX3 do not affect sex determination in mice or humans. To further investigate Sox3 function in vivo, we generated transgenic mice overexpressing Sox3. Here, we report that in one of these transgenic lines, Sox3 was ectopically expressed in the bipotential gonad and that this led to frequent complete XX male sex reversal. Further analysis indicated that Sox3 induced testis differentiation in this particular line of mice by upregulating expression of Sox9 via a similar mechanism to Sry. Importantly, we also identified genomic rearrangements within the SOX3 regulatory region in three patients with XX male sex reversal. Together, these data suggest that SOX3 and SRY are functionally interchangeable in sex determination and support the notion that SRY evolved from SOX3 via a regulatory mutation that led to its de novo expression in the early gonad. PMID:21183788

  13. Dynamic, Sex-Differential STAT5 and BCL6 Binding to Sex-Biased, Growth Hormone-Regulated Genes in Adult Mouse Liver

    PubMed Central

    Zhang, Yijing; Laz, Ekaterina V.

    2012-01-01

    Sex-dependent pituitary growth hormone (GH) secretory patterns determine the sex-biased expression of >1,000 genes in mouse and rat liver, affecting lipid and drug metabolism, inflammation, and disease. A fundamental biological question is how robust differential expression can be achieved for hundreds of sex-biased genes simply based on the GH input signal pattern: pulsatile GH stimulation in males versus near-continuous GH exposure in females. STAT5 is an essential transcriptional mediator of the sex-dependent effects of GH in the liver, but the mechanisms that underlie its sex-dependent actions are obscure. Here we elucidate the dynamic, sex-dependent binding of STAT5 and the GH/STAT5-regulated repressor BCL6 to mouse liver chromatin genome wide, revealing a counteractive interplay between these two regulators of sex differences in liver gene expression. Our findings establish a close correlation between sex-dependent STAT5 binding and sex-biased target gene expression. Moreover, sex-dependent STAT5 binding correlated positively with sex-biased DNase hypersensitivity and H3-K4me1 and H3-K4me3 (activating) marks, correlated negatively with sex-biased H3-K27me3 (repressive) marks, and was associated with sex-differentially enriched motifs for HNF6/CDP factors. Importantly, BCL6 binding was preferentially associated with repression of female-biased STAT5 targets in male liver. Furthermore, BCL6 and STAT5 common targets but not BCL6 unique targets showed strong enrichment for lipid and drug metabolism. These findings provide a comprehensive, genome-wide view of the mechanisms whereby these two GH-regulated transcription factors establish and maintain sex differences affecting liver physiology and disease. The approaches used here to characterize sex-dependent STAT5 and BCL6 binding can be applied to other condition-specific regulatory factors and binding sites and their interplay with cooperative chromatin binding factors. PMID:22158971

  14. Meta-analysis of sex differences in gene expression in schizophrenia.

    PubMed

    Qin, Wenyi; Liu, Cong; Sodhi, Monsheel; Lu, Hui

    2016-01-11

    Schizophrenia is a severe psychiatric disorder which influences around 1% of the worldwide population. Differences between male and female patients with schizophrenia have been noted. There is an earlier age of onset in males compared with females with this diagnosis, and in addition, there are differences in symptom profiles between the sexes. The underlying molecular mechanism of sex difference remains unclear. Here we present a comprehensive analysis to reveal the sex differences in gene expression in schizophrenia with stringent statistics criteria. We compiled a data set consisting of 89 male controls, 90 male schizophrenia patients, 35 female controls and 32 female schizophrenia patients from six independent studies of the prefrontal cortex (PFC) in postmortem brain. When we tested for a sex by diagnosis interaction on gene expression, 23 genes were up-regulated and 23 genes were down-regulated in the male group (q-value < 0.05), several genes are related to energy metabolism, while 4 genes are located on sex chromosome. No genes were statistically significant in the female group when multiple testing correction were conducted (q-value <0.05), most likely due to the small sample size. Our protocol and results from the male group provide a starting point for identifying the underlying different mechanism between male and female schizophrenia patients.

  15. The role of the transformer gene in sex determination and reproduction in the tephritid fruit fly, Bactrocera dorsalis (Hendel)

    USDA-ARS?s Scientific Manuscript database

    Transformer (tra) is a double-switch gene in the somatic sex-determination hierarchy that regulates sexual dimorphism based on RNA splicing in many insects. In tephritids, a Y-linked male determining gene (M) controls sex in the sex-determination pathway. Here, homologues of Drosophila tra and trans...

  16. Influence of sex on gene expression in human corneal epithelial cells

    PubMed Central

    Suzuki, Tomo; Richards, Stephen M.; Liu, Shaohui; Jensen, Roderick V.

    2009-01-01

    Purpose Sex-associated differences have been identified in the anatomy, physiology and pathophysiology of the human cornea. We hypothesize that many of these differences are due to fundamental variations in gene expression. Our objective in this study was to determine whether such differences exist in human corneal epithelial cells both in vivo and in vitro. Methods Human corneal epithelial cells were isolated from the corneoscleral rims of male and female donors. Cells were processed either directly for RNA extraction, or first cultured in phenol red-free keratinocyte serum-free media. The RNA samples were examined for differentially expressed mRNAs by using of CodeLink Bioarrays and Affymetrix GeneChips. Data were analyzed with GeneSifter.Net software. Results Our results demonstrate that sex significantly influences the expression of over 600 genes in human corneal epithelial cells in vivo. These genes are involved in a broad spectrum of biologic processes, molecular functions and cellular components, such as metabolic processes, DNA replication, cell migration, RNA binding, oxidoreductase activity and nucleoli. We also identified significant, sex-related effects on gene expression in human corneal epithelial cells in vitro. However, with few exceptions (e.g., X- and Y-linked genes), these sex-related differences in gene expression in vitro were typically different than those in vivo. Conclusions Our findings support our hypothesis that sex-related differences exist in the gene expression of human corneal epithelial cells. Variations in gene expression may contribute to sex-related differences in the prevalence of certain corneal diseases. PMID:20011627

  17. Comparative transcriptome analysis reveals differentially expressed genes associated with sex expression in garden asparagus (Asparagus officinalis).

    PubMed

    Li, Shu-Fen; Zhang, Guo-Jun; Zhang, Xue-Jin; Yuan, Jin-Hong; Deng, Chuan-Liang; Gao, Wu-Jun

    2017-08-22

    Garden asparagus (Asparagus officinalis) is a highly valuable vegetable crop of commercial and nutritional interest. It is also commonly used to investigate the mechanisms of sex determination and differentiation in plants. However, the sex expression mechanisms in asparagus remain poorly understood. De novo transcriptome sequencing via Illumina paired-end sequencing revealed more than 26 billion bases of high-quality sequence data from male and female asparagus flower buds. A total of 72,626 unigenes with an average length of 979 bp were assembled. In comparative transcriptome analysis, 4876 differentially expressed genes (DEGs) were identified in the possible sex-determining stage of female and male/supermale flower buds. Of these DEGs, 433, including 285 male/supermale-biased and 149 female-biased genes, were annotated as flower related. Of the male/supermale-biased flower-related genes, 102 were probably involved in anther development. In addition, 43 DEGs implicated in hormone response and biosynthesis putatively associated with sex expression and reproduction were discovered. Moreover, 128 transcription factor (TF)-related genes belonging to various families were found to be differentially expressed, and this finding implied the essential roles of TF in sex determination or differentiation in asparagus. Correlation analysis indicated that miRNA-DEG pairs were also implicated in asparagus sexual development. Our study identified a large number of DEGs involved in the sex expression and reproduction of asparagus, including known genes participating in plant reproduction, plant hormone signaling, TF encoding, and genes with unclear functions. We also found that miRNAs might be involved in the sex differentiation process. Our study could provide a valuable basis for further investigations on the regulatory networks of sex determination and differentiation in asparagus and facilitate further genetic and genomic studies on this dioecious species.

  18. Cell-autonomous sex differences in gene expression in chicken bone marrow-derived macrophages.

    PubMed

    Garcia-Morales, Carla; Nandi, Sunil; Zhao, Debiao; Sauter, Kristin A; Vervelde, Lonneke; McBride, Derek; Sang, Helen M; Clinton, Mike; Hume, David A

    2015-03-01

    We have identified differences in gene expression in macrophages grown from the bone marrow of male and female chickens in recombinant chicken M-CSF (CSF1). Cells were profiled with or without treatment with bacterial LPS for 24 h. Approximately 600 transcripts were induced by prolonged LPS stimulation to an equal extent in the male and female macrophages. Many transcripts encoded on the Z chromosome were expressed ∼1.6-fold higher in males, reflecting a lack of dosage compensation in the homogametic sex. A smaller set of W chromosome-specific genes was expressed only in females. LPS signaling in mammals is associated with induction of type 1 IFN-responsive genes. Unexpectedly, because IFNs are encoded on the Z chromosome of chickens, unstimulated macrophages from the female birds expressed a set of known IFN-inducible genes at much higher levels than male cells under the same conditions. To confirm that these differences were not the consequence of the actions of gonadal hormones, we induced gonadal sex reversal to alter the hormonal environment of the developing chick and analyzed macrophages cultured from male, female, and female sex-reversed embryos. Gonadal sex reversal did not alter the sexually dimorphic expression of either sex-linked or IFN-responsive genes. We suggest that female birds compensate for the reduced dose of inducible IFN with a higher basal set point of IFN-responsive genes.

  19. Cell-Autonomous Sex Differences in Gene Expression in Chicken Bone Marrow–Derived Macrophages

    PubMed Central

    Garcia-Morales, Carla; Nandi, Sunil; Zhao, Debiao; Sauter, Kristin A.; Vervelde, Lonneke; McBride, Derek; Sang, Helen M.; Clinton, Mike

    2015-01-01

    We have identified differences in gene expression in macrophages grown from the bone marrow of male and female chickens in recombinant chicken M-CSF (CSF1). Cells were profiled with or without treatment with bacterial LPS for 24 h. Approximately 600 transcripts were induced by prolonged LPS stimulation to an equal extent in the male and female macrophages. Many transcripts encoded on the Z chromosome were expressed ∼1.6-fold higher in males, reflecting a lack of dosage compensation in the homogametic sex. A smaller set of W chromosome–specific genes was expressed only in females. LPS signaling in mammals is associated with induction of type 1 IFN–responsive genes. Unexpectedly, because IFNs are encoded on the Z chromosome of chickens, unstimulated macrophages from the female birds expressed a set of known IFN-inducible genes at much higher levels than male cells under the same conditions. To confirm that these differences were not the consequence of the actions of gonadal hormones, we induced gonadal sex reversal to alter the hormonal environment of the developing chick and analyzed macrophages cultured from male, female, and female sex-reversed embryos. Gonadal sex reversal did not alter the sexually dimorphic expression of either sex-linked or IFN-responsive genes. We suggest that female birds compensate for the reduced dose of inducible IFN with a higher basal set point of IFN-responsive genes. PMID:25637020

  20. Low X/Y divergence in four pairs of papaya sex-linked genes.

    PubMed

    Yu, Qingyi; Hou, Shaobin; Feltus, F Alex; Jones, Meghan R; Murray, Jan E; Veatch, Olivia; Lemke, Cornelia; Saw, Jimmy H; Moore, Richard C; Thimmapuram, Jyothi; Liu, Lei; Moore, Paul H; Alam, Maqsudul; Jiang, Jiming; Paterson, Andrew H; Ming, Ray

    2008-01-01

    Sex chromosomes in flowering plants, in contrast to those in animals, evolved relatively recently and only a few are heteromorphic. The homomorphic sex chromosomes of papaya show features of incipient sex chromosome evolution. We investigated the features of paired X- and Y-specific bacterial artificial chromosomes (BACs), and estimated the time of divergence in four pairs of sex-linked genes. We report the results of a comparative analysis of long contiguous genomic DNA sequences between the X and hermaphrodite Y (Y(h)) chromosomes. Numerous chromosomal rearrangements were detected in the male-specific region of the Y chromosome (MSY), including inversions, deletions, insertions, duplications and translocations, showing the dynamic evolutionary process on the MSY after recombination ceased. DNA sequence expansion was documented in the two regions of the MSY, demonstrating that the cytologically homomorphic sex chromosomes are heteromorphic at the molecular level. Analysis of sequence divergence between four X and Y(h) gene pairs resulted in a estimated age of divergence of between 0.5 and 2.2 million years, supporting a recent origin of the papaya sex chromosomes. Our findings indicate that sex chromosomes did not evolve at the family level in Caricaceae, and reinforce the theory that sex chromosomes evolve at the species level in some lineages.

  1. De Novo Transcriptome Assembly and Sex-Biased Gene Expression in the Cyclical Parthenogenetic Daphnia galeata

    PubMed Central

    Huylmans, Ann Kathrin; López Ezquerra, Alberto; Parsch, John; Cordellier, Mathilde

    2016-01-01

    Daphnia species have become models for ecological genomics and exhibit interesting features, such as high phenotypic plasticity and a densely packed genome with many lineage-specific genes. They are also cyclic parthenogenetic, with alternating asexual and sexual cycles and environmental sex determination. Here, we present a de novo transcriptome assembly of over 32,000 D. galeata genes and use it to investigate gene expression in females and spontaneously produced males of two clonal lines derived from lakes in Germany and the Czech Republic. We find that only a low percentage (18%) of genes shows sex-biased expression and that there are many more female-biased gene (FBG) than male-biased gene (MBG). Furthermore, FBGs tend to be more conserved between species than MBGs in both sequence and expression. These patterns may be a consequence of cyclic parthenogenesis leading to a relaxation of purifying selection on MBGs. The two clonal lines show considerable differences in both number and identity of sex-biased genes, suggesting that they may have reproductive strategies differing in their investment in sexual reproduction. Orthologs of key genes in the sex determination and juvenile hormone pathways, which are thought to be important for the transition from asexual to sexual reproduction, are present in D. galeata and highly conserved among Daphnia species. PMID:27604882

  2. De Novo Transcriptome Assembly and Sex-Biased Gene Expression in the Cyclical Parthenogenetic Daphnia galeata.

    PubMed

    Huylmans, Ann Kathrin; López Ezquerra, Alberto; Parsch, John; Cordellier, Mathilde

    2016-10-23

    Daphnia species have become models for ecological genomics and exhibit interesting features, such as high phenotypic plasticity and a densely packed genome with many lineage-specific genes. They are also cyclic parthenogenetic, with alternating asexual and sexual cycles and environmental sex determination. Here, we present a de novo transcriptome assembly of over 32,000 D. galeata genes and use it to investigate gene expression in females and spontaneously produced males of two clonal lines derived from lakes in Germany and the Czech Republic. We find that only a low percentage (18%) of genes shows sex-biased expression and that there are many more female-biased gene (FBG) than male-biased gene (MBG). Furthermore, FBGs tend to be more conserved between species than MBGs in both sequence and expression. These patterns may be a consequence of cyclic parthenogenesis leading to a relaxation of purifying selection on MBGs. The two clonal lines show considerable differences in both number and identity of sex-biased genes, suggesting that they may have reproductive strategies differing in their investment in sexual reproduction. Orthologs of key genes in the sex determination and juvenile hormone pathways, which are thought to be important for the transition from asexual to sexual reproduction, are present in D. galeata and highly conserved among Daphnia species. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  3. A reference gene set for sex pheromone biosynthesis and degradation genes from the diamondback moth, Plutella xylostella, based on genome and transcriptome digital gene expression analyses.

    PubMed

    He, Peng; Zhang, Yun-Fei; Hong, Duan-Yang; Wang, Jun; Wang, Xing-Liang; Zuo, Ling-Hua; Tang, Xian-Fu; Xu, Wei-Ming; He, Ming

    2017-03-01

    Female moths synthesize species-specific sex pheromone components and release them to attract male moths, which depend on precise sex pheromone chemosensory system to locate females. Two types of genes involved in the sex pheromone biosynthesis and degradation pathways play essential roles in this important moth behavior. To understand the function of genes in the sex pheromone pathway, this study investigated the genome-wide and digital gene expression of sex pheromone biosynthesis and degradation genes in various adult tissues in the diamondback moth (DBM), Plutella xylostella, which is a notorious vegetable pest worldwide. A massive transcriptome data (at least 39.04 Gb) was generated by sequencing 6 adult tissues including male antennae, female antennae, heads, legs, abdomen and female pheromone glands from DBM by using Illumina 4000 next-generation sequencing and mapping to a published DBM genome. Bioinformatics analysis yielded a total of 89,332 unigenes among which 87 transcripts were putatively related to seven gene families in the sex pheromone biosynthesis pathway. Among these, seven [two desaturases (DES), three fatty acyl-CoA reductases (FAR) one acetyltransferase (ACT) and one alcohol dehydrogenase (AD)] were mainly expressed in the pheromone glands with likely function in the three essential sex pheromone biosynthesis steps: desaturation, reduction, and esterification. We also identified 210 odorant-degradation related genes (including sex pheromone-degradation related genes) from seven major enzyme groups. Among these genes, 100 genes are new identified and two aldehyde oxidases (AOXs), one aldehyde dehydrogenase (ALDH), five carboxyl/cholinesterases (CCEs), five UDP-glycosyltransferases (UGTs), eight cytochrome P450 (CYP) and three glutathione S-transferases (GSTs) displayed more robust expression in the antennae, and thus are proposed to participate in the degradation of sex pheromone components and plant volatiles. To date, this is the most

  4. Sex identification using the ZFX and ZFY genes in common marmosets (Callithrix jacchus).

    PubMed

    Takabayashi, Shuji; Katoh, Hideki

    2011-01-01

    We investigated sex determination via the ZFX and ZFY genes using PCR-RFLP in the common marmoset. We designed a novel primer set to detect ZFX and ZFY. A 483-bp band from the ZFX gene and a 471-bp band from the ZFY gene were amplified. Sequencing data of the products amplified from ZFX and ZFY showed the recognition sites of two restriction enzymes, DdeI and MseI, respectively. After digestion of the products using each enzyme, we found that the band patterns between females and males were different. PCR-based sex identification might provide a tool for further breeding studies and experimental embryological studies using marmosets.

  5. Sexually dimorphic gene expressions in eels: useful markers for early sex assessment in a conservation context

    NASA Astrophysics Data System (ADS)

    Geffroy, Benjamin; Guilbaud, Florian; Amilhat, Elsa; Beaulaton, Laurent; Vignon, Matthias; Huchet, Emmanuel; Rives, Jacques; Bobe, Julien; Fostier, Alexis; Guiguen, Yann; Bardonnet, Agnès

    2016-09-01

    Environmental sex determination (ESD) has been detected in a range of vertebrate reptile and fish species. Eels are characterized by an ESD that occurs relatively late, since sex cannot be histologically determined before individuals reach 28 cm. Because several eel species are at risk of extinction, assessing sex at the earliest stage is a crucial management issue. Based on preliminary results of RNA sequencing, we targeted genes susceptible to be differentially expressed between ovaries and testis at different stages of development. Using qPCR, we detected testis-specific expressions of dmrt1, amh, gsdf and pre-miR202 and ovary-specific expressions were obtained for zar1, zp3 and foxn5. We showed that gene expressions in the gonad of intersexual eels were quite similar to those of males, supporting the idea that intersexual eels represent a transitional stage towards testicular differentiation. To assess whether these genes would be effective early molecular markers, we sampled juvenile eels in two locations with highly skewed sex ratios. The combined expression of six of these genes allowed the discrimination of groups according to their potential future sex and thus this appears to be a useful tool to estimate sex ratios of undifferentiated juvenile eels.

  6. Sexually dimorphic gene expressions in eels: useful markers for early sex assessment in a conservation context

    PubMed Central

    Geffroy, Benjamin; Guilbaud, Florian; Amilhat, Elsa; Beaulaton, Laurent; Vignon, Matthias; Huchet, Emmanuel; Rives, Jacques; Bobe, Julien; Fostier, Alexis; Guiguen, Yann; Bardonnet, Agnès

    2016-01-01

    Environmental sex determination (ESD) has been detected in a range of vertebrate reptile and fish species. Eels are characterized by an ESD that occurs relatively late, since sex cannot be histologically determined before individuals reach 28 cm. Because several eel species are at risk of extinction, assessing sex at the earliest stage is a crucial management issue. Based on preliminary results of RNA sequencing, we targeted genes susceptible to be differentially expressed between ovaries and testis at different stages of development. Using qPCR, we detected testis-specific expressions of dmrt1, amh, gsdf and pre-miR202 and ovary-specific expressions were obtained for zar1, zp3 and foxn5. We showed that gene expressions in the gonad of intersexual eels were quite similar to those of males, supporting the idea that intersexual eels represent a transitional stage towards testicular differentiation. To assess whether these genes would be effective early molecular markers, we sampled juvenile eels in two locations with highly skewed sex ratios. The combined expression of six of these genes allowed the discrimination of groups according to their potential future sex and thus this appears to be a useful tool to estimate sex ratios of undifferentiated juvenile eels. PMID:27658729

  7. Evolution in the fast lane: rapidly evolving sex-related genes in Drosophila.

    PubMed

    Haerty, Wilfried; Jagadeeshan, Santosh; Kulathinal, Rob J; Wong, Alex; Ravi Ram, Kristipati; Sirot, Laura K; Levesque, Lisa; Artieri, Carlo G; Wolfner, Mariana F; Civetta, Alberto; Singh, Rama S

    2007-11-01

    A large portion of the annotated genes in Drosophila melanogaster show sex-biased expression, indicating that sex and reproduction-related genes (SRR genes) represent an appreciable component of the genome. Previous studies, in which subsets of genes were compared among few Drosophila species, have found that SRR genes exhibit unusual evolutionary patterns. Here, we have used the newly released genome sequences from 12 Drosophila species, coupled to a larger set of SRR genes, to comprehensively test the generality of these patterns. Among 2505 SRR genes examined, including ESTs with biased expression in reproductive tissues and genes characterized as involved in gametogenesis, we find that a relatively high proportion of SRR genes have experienced accelerated divergence throughout the genus Drosophila. Several testis-specific genes, male seminal fluid proteins (SFPs), and spermatogenesis genes show lineage-specific bursts of accelerated evolution and positive selection. SFP genes also show evidence of lineage-specific gene loss and/or gain. These results bring us closer to understanding the details of the evolutionary dynamics of SRR genes with respect to species divergence.

  8. Evolution in the Fast Lane: Rapidly Evolving Sex-Related Genes in Drosophila

    PubMed Central

    Haerty, Wilfried; Jagadeeshan, Santosh; Kulathinal, Rob J.; Wong, Alex; Ravi Ram, Kristipati; Sirot, Laura K.; Levesque, Lisa; Artieri, Carlo G.; Wolfner, Mariana F.; Civetta, Alberto; Singh, Rama S.

    2007-01-01

    A large portion of the annotated genes in Drosophila melanogaster show sex-biased expression, indicating that sex and reproduction-related genes (SRR genes) represent an appreciable component of the genome. Previous studies, in which subsets of genes were compared among few Drosophila species, have found that SRR genes exhibit unusual evolutionary patterns. Here, we have used the newly released genome sequences from 12 Drosophila species, coupled to a larger set of SRR genes, to comprehensively test the generality of these patterns. Among 2505 SRR genes examined, including ESTs with biased expression in reproductive tissues and genes characterized as involved in gametogenesis, we find that a relatively high proportion of SRR genes have experienced accelerated divergence throughout the genus Drosophila. Several testis-specific genes, male seminal fluid proteins (SFPs), and spermatogenesis genes show lineage-specific bursts of accelerated evolution and positive selection. SFP genes also show evidence of lineage-specific gene loss and/or gain. These results bring us closer to understanding the details of the evolutionary dynamics of SRR genes with respect to species divergence. PMID:18039869

  9. Mapping platypus SOX genes; autosomal location of SOX9 excludes it from sex determining role.

    PubMed

    Wallis, M C; Delbridge, M L; Pask, A J; Alsop, A E; Grutzner, F; O'Brien, P C M; Rens, W; Ferguson-Smith, M A; Graves, J A M

    2007-01-01

    In the absence of an SRY orthologue the platypus sex determining gene is unknown, so genes in the human testis determining pathway are of particular interest as candidates. SOX9 is an attractive choice because SOX9 deletions cause male-to-female sex reversal in humans and mice, and SOX9 duplications cause female-to-male sex reversal. We have localized platypus SOX9, as well as the related SOX10, to platypus chromosomes 15 and 10, respectively, the first assignments to these platypus chromosomes, and the first comparative mapping markers from human chromosomes 17 and 22. The autosomal localization of platypus SOX9 in this study contradicts the hypothesis that SOX9 acts as the sex determining switch in platypus.

  10. Comparison of homeobox-containing genes of the honeybee and Drosophila.

    PubMed Central

    Walldorf, U; Fleig, R; Gehring, W J

    1989-01-01

    We report the isolation of seven homeobox-containing genes from the honeybee (Apis mellifera). Sequence analysis of all homeoboxes and some flanking sequences showed that six of seven genes are more than 90% identical to their corresponding Drosophila homologues within the homeobox and, with one exception, also in the flanking sequences. The homologues that were identified include three homeotic selector genes [Sex combs reduced (Scr), Antennapedia (Antp), and abdominal-A (abd-A); the two engrailed (en) genes; and the muscle segment homeobox (msh)]. Surprisingly, no homologue of the segmentation gene fushi tarazu was found in the honeybee. For the remaining bee gene, a Drosophila homologue is not known. This indicates that, with some exceptions, structurally homologous genes are involved in the control of bee and Drosophila development, although Hymenoptera differ significantly in their embryogenesis from Diptera and have evolved separately for some 250 million years. Images PMID:2574865

  11. Sex identification based on AMEL gene PCR amplification from blue sheep (Pseudois nayaur) fecal DNA samples.

    PubMed

    Liu, X; Yang, Y Y; Wang, X M; Liu, Z S; Wang, Z H; Ding, Y Z

    2015-08-07

    The use of noninvasive genetic sampling to identify the sex of wild animals is an extremely valuable and important tool in molecular ecology and wildlife conservation. Sex determination using the amelogenin gene has been conducted in many species because only a single pair of primers is required to amplify both X- and Y-linked alleles. However, this method has not been used in field research with the feces of wildlife. In this study, we applied this method to 222 fecal samples from wild blue sheep (Pseudois nayaur) using amelogenin primers (SE47/SE48) after testing the effectiveness of sex determination using tissue samples and fecal samples from blue sheep of known sex. We found this method to be highly reliable (80.2%) for blue sheep. Amelogenin can be used to identify the sex of wild animals using fecal samples.

  12. Molecular evolution of sex-biased genes in the Drosophila ananassae subgroup

    PubMed Central

    2009-01-01

    Background Genes with sex-biased expression often show rapid molecular evolution between species. Previous population genetic and comparative genomic studies of Drosophila melanogaster and D. simulans revealed that male-biased genes have especially high rates of adaptive evolution. To test if this is also the case for other lineages within the melanogaster group, we investigated gene expression in D. ananassae, a species that occurs in structured populations in tropical and subtropical regions. We used custom-made microarrays and published microarray data to characterize the sex-biased expression of 129 D. ananassae genes whose D. melanogaster orthologs had been classified previously as male-biased, female-biased, or unbiased in their expression and had been studied extensively at the population-genetic level. For 43 of these genes we surveyed DNA sequence polymorphism in a natural population of D. ananassae and determined divergence to the sister species D. atripex and D. phaeopleura. Results Sex-biased expression is generally conserved between D. melanogaster and D. ananassae, with the majority of genes exhibiting the same bias in the two species. However, about one-third of the genes have either gained or lost sex-biased expression in one of the species and a small proportion of genes (~4%) have changed bias from one sex to the other. The male-biased genes of D. ananassae show evidence of positive selection acting at the protein level. However, the signal of adaptive protein evolution for male-biased genes is not as strong in D. ananassae as it is in D. melanogaster and is limited to genes with conserved male-biased expression in both species. Within D. ananassae, a significant signal of adaptive evolution is also detected for female-biased and unbiased genes. Conclusions Our findings extend previous observations of widespread adaptive protein evolution to an independent Drosophila lineage, the D. ananassae subgroup. However, the rate of adaptive evolution is

  13. Sex-based differences in gene expression in hippocampus following postnatal lead exposure

    SciTech Connect

    Schneider, J.S. Anderson, D.W.; Sonnenahalli, H.; Vadigepalli, R.

    2011-10-15

    The influence of sex as an effect modifier of childhood lead poisoning has received little systematic attention. Considering the paucity of information available concerning the interactive effects of lead and sex on the brain, the current study examined the interactive effects of lead and sex on gene expression patterns in the hippocampus, a structure involved in learning and memory. Male or female rats were fed either 1500 ppm lead-containing chow or control chow for 30 days beginning at weaning.Blood lead levels were 26.7 {+-} 2.1 {mu}g/dl and 27.1 {+-} 1.7 {mu}g/dl for females and males, respectively. The expression of 175 unique genes was differentially regulated between control male and female rats. A total of 167 unique genes were differentially expressed in response to lead in either males or females. Lead exposure had a significant effect without a significant difference between male and female responses in 77 of these genes. In another set of 71 genes, there were significant differences in male vs. female response. A third set of 30 genes was differentially expressed in opposite directions in males vs. females, with the majority of genes expressed at a lower level in females than in males. Highly differentially expressed genes in males and females following lead exposure were associated with diverse biological pathways and functions. These results show that a brief exposure to lead produced significant changes in expression of a variety of genes in the hippocampus and that the response of the brain to a given lead exposure may vary depending on sex. - Highlights: > Postnatal lead exposure has a significant effect on hippocampal gene expression patterns. > At least one set of genes was affected in opposite directions in males and females. > Differentially expressed genes were associated with diverse biological pathways.

  14. Morphology, sex steroid level and gene expression analysis in gonadal sex reversal of triploid female (XXX) rainbow trout (Oncorhynchus mykiss).

    PubMed

    Xu, Gefeng; Huang, Tianqing; Jin, Xian; Cui, Cunhe; Li, Depeng; Sun, Cong; Han, Ying; Mu, Zhenbo

    2016-02-01

    In non-mammalian vertebrates, estrogens and expressions of cyp19a1 and foxl2 play critical roles in maintaining ovary differentiation and development, while dmrt1 and sox9 are male-specific genes in testicular differentiation and are highly conserved. In order to deeply understand the morphological change, sex steroids level and molecular mechanism of triploid female gonadal reversal in rainbow trout, we studied the ovary morphology, tendency of estradiol-17β (E2) and testosterone (T) levels and the relative expressions of dmrt1, cyp19a1, sox9 and foxl2 in juvenile and adult fish. Our results demonstrated that the development of triploid female gonads in rainbow trout went through arrested development, oocytes dedifferentiation, ovary reconstruction and sex reversal finally. During early gonadal development (154-334 days post-fertilization), the expressions of foxl2 and cyp19a1 increased linearly, while expressions of dmrt1 and sox9 were extremely suppressed, and E2 level was higher, while T level was lower. During the mid-to-late period of triploid female gonadal development (574-964 days post-fertilization), the expressions of dmrt1 and sox9 remained high and were very close to the quantity of diploid male genes, and T levels were even reaching diploid male plasma concentrations, while expressions of cyp19a1 and foxl2 were decreased, leading to decrease in E2 level. We realized that the development model of rainbow trout triploid female gonads was extremely rare, and the regulatory mechanism was very special. Genes involved in gonadal development and endogenous estrogens are pivotal factors in fish natural sex reversal.

  15. Disentangling the relationship between sex-biased gene expression and X-linkage

    PubMed Central

    Meisel, Richard P.; Malone, John H.; Clark, Andrew G.

    2012-01-01

    X chromosomes are preferentially transmitted through females, which may favor the accumulation of X-linked alleles/genes with female-beneficial effects. Numerous studies have shown that genes with sex-biased expression are under- or over-represented on the X chromosomes of a wide variety of organisms. The patterns, however, vary between different animal species, and the causes of these differences are unresolved. Additionally, genes with sex-biased expression tend to be narrowly expressed in a limited number of tissues, and narrowly expressed genes are also non-randomly X-linked in a taxon-specific manner. It is therefore unclear whether the unique gene content of the X chromosome is the result of selection on genes with sex-biased expression, narrowly expressed genes, or some combination of the two. To address this problem, we measured sex-biased expression in multiple Drosophila species and at different developmental time points. These data were combined with available expression measurements from Drosophila melanogaster and mouse to reconcile the inconsistencies in X-chromosome content among taxa. Our results suggest that most of the differences between Drosophila and mammals are confounded by disparate data collection/analysis approaches as well as the correlation between sex bias and expression breadth. Both the Drosophila and mouse X chromosomes harbor an excess of genes with female-biased expression after controlling for the confounding factors, suggesting that the asymmetrical transmission of the X chromosome favors the accumulation of female-beneficial mutations in X-linked genes. However, some taxon-specific patterns remain, and we provide evidence that these are in part a consequence of constraints imposed by the dosage compensation mechanism in Drosophila. PMID:22499666

  16. Sex-biased gene flow among elk in the greater Yellowstone ecosystem

    USGS Publications Warehouse

    , Brian K. Hand; , Shanyuan Chen; , N. Anderson; , A. Beja-Pereira; Cross, Paul C.; , M. Ebinger; , H. Edwards; , R.A. Garrott; , M.D. Kardos; Kauffman, Matthew J.; , E.L. Landguth; , A. Middleton; , B. Scurlock; , P.J. White; , P. Zager; , M.K. Schwartz; , G. Luikart

    2014-01-01

    We quantified patterns of population genetic structure to help understand gene flow among elk populations across the Greater Yellowstone Ecosystem. We sequenced 596 base pairs of the mitochondrial control region of 380 elk from eight populations. Analysis revealed high mitochondrial DNA variation within populations, averaging 13.0 haplotypes with high mean gene diversity (0.85). The genetic differentiation among populations for mitochondrial DNA was relatively high (FST = 0.161; P = 0.001) compared to genetic differentiation for nuclear microsatellite data (FST = 0.002; P = 0.332), which suggested relatively low female gene flow among populations. The estimated ratio of male to female gene flow (mm/mf = 46) was among the highest we have seen reported for large mammals. Genetic distance (for mitochondrial DNA pairwise FST) was not significantly correlated with geographic (Euclidean) distance between populations (Mantel’s r = 0.274, P = 0.168). Large mitochondrial DNA genetic distances (e.g., FST > 0.2) between some of the geographically closest populations (<65 km) suggested behavioral factors and/or landscape features might shape female gene flow patterns. Given the strong sex-biased gene flow, future research and conservation efforts should consider the sexes separately when modeling corridors of gene flow or predicting spread of maternally transmitted diseases. The growing availability of genetic data to compare male vs. female gene flow provides many exciting opportunities to explore the magnitude, causes, and implications of sex-biased gene flow likely to occur in many species

  17. Differential expression of sex-linked and autosomal germ-cell-specific genes during spermatogenesis in the mouse.

    PubMed

    Wang, P Jeremy; Page, David C; McCarrey, John R

    2005-10-01

    We have examined expression during spermatogenesis in the mouse of three Y-linked genes, 11 X-linked genes and 22 autosomal genes, all previously shown to be germ-cell-specific and expressed in premeiotic spermatogonia, plus another 21 germ-cell-specific autosomal genes that initiate expression in meiotic spermatocytes. Our data demonstrate that, like sex-linked housekeeping genes, germ-cell-specific sex-linked genes are subject to meiotic sex-chromosome inactivation (MSCI). Although all the sex-linked genes we investigated underwent MSCI, 14 of the 22 autosomal genes expressed in spermatogonia showed no decrease in expression in meiotic spermatocytes. This along with our observation that an additional 21 germ-cell-specific autosomal genes initiate or significantly up-regulate expression in spermatocytes confirms that MSCI is indeed a sex-chromosome-specific effect. Our results further demonstrate that the chromosome-wide repression imposed by MSCI is limited to meiotic spermatocytes and that postmeiotic expression of sex-linked genes is variable. Thus, 13 of the 14 sex-linked genes we examined showed some degree of postmeiotic reactivation. The extent of postmeiotic reactivation of germ-cell-specific X-linked genes did not correlate with proximity to the X inactivation center or the Xist gene locus. The implications of these findings are discussed with respect to differential gene regulation and the function of MSCI during spermatogenesis, including epigenetic programming of the future paternal genome during spermatogenesis.

  18. Molecular Basis of Prostate-Specific Androgen-Independent Expression of a Homeobox Gene

    DTIC Science & Technology

    2002-04-01

    genes are homologs of Dro- g sophila homeotic genes that encode homeodomain meobox-containing genes have been implicated in transcription factors [1...Expression of the homeotic gene Hox-d13 in the developing and adult mouse cells and is androgen-dependent [14,21,22]. nkx-3.1 is prostate. J Urol...Expression of a Homeobox Gene PRINCIPAL INVESTIGATOR: Charles J. Bieberich, Ph.D. CONTRACTING ORGANIZATION: University of Maryland, Baltimore County

  19. Sex pheromones and gene transfer in Enterococcus faecalis.

    PubMed

    Wirth, R

    2000-01-01

    Cell-density-dependent regulatory controls have been recognized in recent years to play major roles with regard to many microorganisms. In gram-negative bacteria very often N-acyl-homoserine lactones act as 'quorum-sensing' regulators, whilst gram-positive bacteria mainly use peptides to monitor their cell density. The so-called sex pheromone system of Enterococcus faecalis is just one example of the latter type of regulation. The system is a complex one; in this communication, I will discuss in particular the potential role of the peptides to also act as virulence factors.

  20. The Caenorhabditis Elegans Gene Sdc-2 Controls Sex Determination and Dosage Compensation in Xx Animals

    PubMed Central

    Nusbaum, C.; Meyer, B. J.

    1989-01-01

    We have identified a new X-linked gene, sdc-2, that controls the hermaphrodite (XX) modes of both sex determination and X chromosome dosage compensation in Caenorhabditis elegans. Mutations in sdc-2 cause phenotypes that appear to result from a shift of both the sex determination and dosage compensation processes in XX animals to the XO modes of expression. Twenty-eight independent sdc-2 mutations have no apparent effect in XO animals, but cause two distinct phenotypes in XX animals: masculinization, reflecting a defect in sex determination, and lethality or dumpiness, reflecting a disruption in dosage compensation. The dosage compensation defect can be demonstrated directly by showing that sdc-2 mutations cause elevated levels of several X-linked transcripts in XX but not XO animals. While the masculinization is blocked by mutations in sex determining genes required for male development (her-1 and fem-3), the lethality, dumpiness and overexpression of X-linked genes are not, indicating that the effect of sdc-2 mutations on sex determination and dosage compensation are ultimately implemented by two independent pathways. We propose a model in which sdc-2 is involved in the coordinate control of both sex determination and dosage compensation in XX animals and acts in the regulatory hierarchy at a step prior to the divergence of the two pathways. PMID:2759421

  1. Small Ubiquitin-like Modifier (SUMO) Conjugation Impedes Transcriptional Silencing by the Polycomb Group Repressor Sex Comb on Midleg*

    PubMed Central

    Smith, Matthew; Mallin, Daniel R.; Simon, Jeffrey A.; Courey, Albert J.

    2011-01-01

    The Drosophila protein Sex Comb on Midleg (Scm) is a member of the Polycomb group (PcG), a set of transcriptional repressors that maintain silencing of homeotic genes during development. Recent findings have identified PcG proteins both as targets for modification by the small ubiquitin-like modifier (SUMO) protein and as catalytic components of the SUMO conjugation pathway. We have found that the SUMO-conjugating enzyme Ubc9 binds to Scm and that this interaction, which requires the Scm C-terminal sterile α motif (SAM) domain, is crucial for the efficient sumoylation of Scm. Scm is associated with the major Polycomb response element (PRE) of the homeotic gene Ultrabithorax (Ubx), and efficient PRE recruitment requires an intact Scm SAM domain. Global reduction of sumoylation augments binding of Scm to the PRE. This is likely to be a direct effect of Scm sumoylation because mutations in the SUMO acceptor sites in Scm enhance its recruitment to the PRE, whereas translational fusion of SUMO to the Scm N terminus interferes with this recruitment. In the metathorax, Ubx expression promotes haltere formation and suppresses wing development. When SUMO levels are reduced, we observe decreased expression of Ubx and partial haltere-to-wing transformation phenotypes. These observations suggest that SUMO negatively regulates Scm function by impeding its recruitment to the Ubx major PRE. PMID:21278366

  2. Sex-Biased Gene Expression and Evolution of the X Chromosome in Nematodes

    PubMed Central

    Albritton, Sarah Elizabeth; Kranz, Anna-Lena; Rao, Prashant; Kramer, Maxwell; Dieterich, Christoph; Ercan, Sevinç

    2014-01-01

    Studies of X chromosome evolution in various organisms have indicated that sex-biased genes are nonrandomly distributed between the X and autosomes. Here, to extend these studies to nematodes, we annotated and analyzed X chromosome gene content in four Caenorhabditis species and in Pristionchus pacificus. Our gene expression analyses comparing young adult male and female mRNA-seq data indicate that, in general, nematode X chromosomes are enriched for genes with high female-biased expression and depleted of genes with high male-biased expression. Genes with low sex-biased expression do not show the same trend of X chromosome enrichment and depletion. Combined with the observation that highly sex-biased genes are primarily expressed in the gonad, differential distribution of sex-biased genes reflects differences in evolutionary pressures linked to tissue-specific regulation of X chromosome transcription. Our data also indicate that X dosage imbalance between males (XO) and females (XX) is influential in shaping both expression and gene content of the X chromosome. Predicted upregulation of the single male X to match autosomal transcription (Ohno’s hypothesis) is supported by our observation that overall transcript levels from the X and autosomes are similar for highly expressed genes. However, comparison of differentially located one-to-one orthologs between C. elegans and P. pacificus indicates lower expression of X-linked orthologs, arguing against X upregulation. These contradicting observations may be reconciled if X upregulation is not a global mechanism but instead acts locally on a subset of tissues and X-linked genes that are dosage sensitive. PMID:24793291

  3. Sex-biased gene expression and evolution of the x chromosome in nematodes.

    PubMed

    Albritton, Sarah Elizabeth; Kranz, Anna-Lena; Rao, Prashant; Kramer, Maxwell; Dieterich, Christoph; Ercan, Sevinç

    2014-07-01

    Studies of X chromosome evolution in various organisms have indicated that sex-biased genes are nonrandomly distributed between the X and autosomes. Here, to extend these studies to nematodes, we annotated and analyzed X chromosome gene content in four Caenorhabditis species and in Pristionchus pacificus. Our gene expression analyses comparing young adult male and female mRNA-seq data indicate that, in general, nematode X chromosomes are enriched for genes with high female-biased expression and depleted of genes with high male-biased expression. Genes with low sex-biased expression do not show the same trend of X chromosome enrichment and depletion. Combined with the observation that highly sex-biased genes are primarily expressed in the gonad, differential distribution of sex-biased genes reflects differences in evolutionary pressures linked to tissue-specific regulation of X chromosome transcription. Our data also indicate that X dosage imbalance between males (XO) and females (XX) is influential in shaping both expression and gene content of the X chromosome. Predicted upregulation of the single male X to match autosomal transcription (Ohno's hypothesis) is supported by our observation that overall transcript levels from the X and autosomes are similar for highly expressed genes. However, comparison of differentially located one-to-one orthologs between C. elegans and P. pacificus indicates lower expression of X-linked orthologs, arguing against X upregulation. These contradicting observations may be reconciled if X upregulation is not a global mechanism but instead acts locally on a subset of tissues and X-linked genes that are dosage sensitive.

  4. Molecular interactions of orthologues of floral homeotic proteins from the gymnosperm Gnetum gnemon provide a clue to the evolutionary origin of 'floral quartets'.

    PubMed

    Wang, Yong-Qiang; Melzer, Rainer; Theissen, Günter

    2010-10-01

    Several lines of evidence suggest that the identity of floral organs in angiosperms is specified by multimeric transcription factor complexes composed of MADS-domain proteins. These bind to specific cis-regulatory elements ('CArG-boxes') of their target genes involving DNA-loop formation, thus constituting 'floral quartets'. Gymnosperms, angiosperms' closest relatives, contain orthologues of floral homeotic genes, but when and how the interactions constituting floral quartets were established during evolution has remained unknown. We have comprehensively studied the dimerization and DNA-binding of several classes of MADS-domain proteins from the gymnosperm Gnetum gnemon. Determination of protein-protein and protein-DNA interactions by yeast two-hybrid, in vitro pull-down and electrophoretic mobility shift assays revealed complex patterns of homo- and heterodimerization among orthologues of floral homeotic class B, class C and class E proteins and B(sister) proteins. Using DNase I footprint assays we demonstrate that both orthologues of class B with C proteins, and orthologues of class C proteins alone, but not orthologues of class B proteins alone can loop DNA in floral quartet-like complexes. This is in contrast to class B and class C proteins from angiosperms, which require other factors such as class E floral homeotic proteins to 'glue' them together in multimeric complexes. Our findings suggest that the evolutionary origin of floral quartet formation is based on the interaction of different DNA-bound homodimers, does not depend on class E proteins, and predates the origin of angiosperms. © 2010 The Authors. Journal compilation © 2010 Blackwell Publishing Ltd.

  5. Extraordinary Diversity in the Origins of Sex Chromosomes in Anurans Inferred from Comparative Gene Mapping.

    PubMed

    Uno, Yoshinobu; Nishida, Chizuko; Takagi, Chiyo; Igawa, Takeshi; Ueno, Naoto; Sumida, Masayuki; Matsuda, Yoichi

    2015-01-01

    Sex determination in frogs (anurans) is genetic and includes both male and female heterogamety. However, the origins of the sex chromosomes and their differentiation processes are poorly known. To investigate diversity in the origins of anuran sex chromosomes, we compared the chromosomal locations of sex-linked genes in 4 species: the African clawed frog (Xenopus laevis), the Western clawed frog (Silurana/X. tropicalis), the Japanese bell-ring frog (Buergeria buergeri), and the Japanese wrinkled frog (Rana rugosa). Comparative mapping data revealed that the sex chromosomes of X. laevis, X. tropicalis and R. rugosa are different chromosome pairs; however, the sex chromosomes of X. tropicalis and B. buergeri are homologous, although this may represent distinct evolutionary origins. We also examined the status of sex chromosomal differentiation in B. buergeri, which possesses heteromorphic ZW sex chromosomes, using comparative genomic hybridization and chromosome painting with DNA probes from the microdissected W chromosome. At least 3 rearrangement events have occurred in the proto-W chromosome: deletion of the nucleolus organizer region and a paracentric inversion followed by amplification of non-W-specific repetitive sequences.

  6. Effects of thyroid endocrine manipulation on sex-related gene expression and population sex ratios in Zebrafish.

    PubMed

    Sharma, Prakash; Tang, Song; Mayer, Gregory D; Patiño, Reynaldo

    2016-09-01

    Thyroid hormone reportedly induces masculinization of genetic females and goitrogen treatment delays testicular differentiation (ovary-to-testis transformation) in genetic males of Zebrafish. This study explored potential molecular mechanisms of these phenomena. Zebrafish were treated with thyroxine (T4, 2nM), goitrogen [methimazole (MZ), 0.15mM], MZ (0.15mM) and T4 (2nM) (rescue treatment), or reconstituted water (control) from 3 to 33days postfertilization (dpf) and maintained in control water until 45dpf. Whole fish were collected during early (25dpf) and late (45dpf) testicular differentiation for transcript abundance analysis of selected male (dmrt1, amh, ar) and female (cyp19a1a, esr1, esr2a, esr2b) sex-related genes by quantitative RT-PCR, and fold-changes relative to control values were determined. Additional fish were sampled at 45dpf for histological assessment of gonadal sex. The T4 and rescue treatments caused male-biased populations, and T4 alone induced precocious puberty in ∼50% of males. Male-biased sex ratios were accompanied by increased expression of amh and ar and reduced expression of cyp19a1a, esr1, esr2a, and esr2b at 25 and 45dpf and, unexpectedly, reduced expression of dmrt1 at 45dpf. Goitrogen exposure increased the proportion of individuals with ovaries (per previous studies interpreted as delay in testicular differentiation of genetic males), and at 25 and 45dpf reduced the expression of amh and ar and increased the expression of esr1 (only at 25dpf), esr2a, and esr2b. Notably, cyp19a1a transcript was reduced but via non-thyroidal pathways (not restored by rescue treatment). In conclusion, the masculinizing activity of T4 at the population level may be due to its ability to inhibit female and stimulate male sex-related genes in larvae, while the inability of MZ to induce cyp19a1a, which is necessary for ovarian differentiation, may explain why its "feminizing" activity on gonadal sex is not permanent. Published by Elsevier Inc.

  7. Effects of thyroid endocrine manipulation on sex-related gene expression and population sex ratios in Zebrafish

    USGS Publications Warehouse

    Sharma, Prakash; Tang, Song; Mayer, Gregory D.; Patino, Reynaldo

    2016-01-01

    Thyroid hormone reportedly induces masculinization of genetic females and goitrogen treatment delays testicular differentiation (ovary-to-testis transformation) in genetic males of Zebrafish. This study explored potential molecular mechanisms of these phenomena. Zebrafish were treated with thyroxine (T4, 2 nM), goitrogen [methimazole (MZ), 0.15 mM], MZ (0.15 mM) and T4 (2 nM) (rescue treatment), or reconstituted water (control) from 3 to 33 days postfertilization (dpf) and maintained in control water until 45 dpf. Whole fish were collected during early (25 dpf) and late (45 dpf) testicular differentiation for transcript abundance analysis of selected male (dmrt1, amh, ar) and female (cyp19a1a, esr1, esr2a, esr2b) sex-related genes by quantitative RT-PCR, and fold-changes relative to control values were determined. Additional fish were sampled at 45 dpf for histological assessment of gonadal sex. The T4 and rescue treatments caused male-biased populations, and T4 alone induced precocious puberty in ∼50% of males. Male-biased sex ratios were accompanied by increased expression of amh and ar and reduced expression of cyp19a1a, esr1, esr2a, and esr2b at 25 and 45 dpf and, unexpectedly, reduced expression of dmrt1 at 45 dpf. Goitrogen exposure increased the proportion of individuals with ovaries (per previous studies interpreted as delay in testicular differentiation of genetic males), and at 25 and 45 dpf reduced the expression of amh and ar and increased the expression of esr1 (only at 25 dpf), esr2a, and esr2b. Notably, cyp19a1a transcript was reduced but via non-thyroidal pathways (not restored by rescue treatment). In conclusion, the masculinizing activity of T4 at the population level may be due to its ability to inhibit female and stimulate male sex-related genes in larvae, while the inability of MZ to induce cyp19a1a, which is necessary for ovarian differentiation, may explain why its “feminizing” activity on gonadal

  8. Zfy genes are required for efficient meiotic sex chromosome inactivation (MSCI) in spermatocytes.

    PubMed

    Vernet, Nadège; Mahadevaiah, Shantha K; de Rooij, Dirk G; Burgoyne, Paul S; Ellis, Peter J I

    2016-10-13

    During spermatogenesis, germ cells that fail to synapse their chromosomes or fail to undergo meiotic sex chromosome inactivation (MSCI) are eliminated via apoptosis during mid-pachytene. Previous work showed that Y-linked genes Zfy1 and Zfy2 act as 'executioners' for this checkpoint, and that wrongful expression of either gene during pachytene triggers germ cell death. Here, we show that in mice, Zfy genes are also necessary for efficient MSCI and the sex chromosomes are not correctly silenced in Zfy-deficient spermatocytes. This unexpectedly reveals a triple role for Zfy at the mid-pachytene checkpoint in which Zfy genes first promote MSCI, then monitor its progress (since if MSCI is achieved, Zfy genes will be silenced), and finally execute cells with MSCI failure. This potentially constitutes a negative feedback loop governing this critical checkpoint mechanism.

  9. The complex set of late transcripts from the Drosophila sex determination gene sex-lethal encodes multiple related polypeptides.

    PubMed Central

    Samuels, M E; Schedl, P; Cline, T W

    1991-01-01

    Sex-lethal (Sxl), a key sex determination gene in Drosophila melanogaster, is known to express a set of three early transcripts arising during early embryogenesis and a set of seven late transcripts occurring from midembryogenesis through adulthood. Among the late transcripts, male-specific mRNAs were distinguished from their female counterparts by the presence of an extra exon interrupting an otherwise long open reading frame (ORF). We have now analyzed the structures of the late Sxl transcripts by cDNA sequencing, Northern (RNA) blotting, primer extension, and RNase protection. The late transcripts appear to use a common 5' end but differ at their 3' ends by the use of alternative polyadenylation sites. Two of these sites lack canonical AATAAA sequences, and their use correlates in females with the presence of a functional germ line, suggesting possible tissue-specific polyadenylation. Besides the presence of the male-specific exon, no additional sex-specific splicing events were detected, although a number of non-sex-specific splicing variants were observed. In females, the various forms of late Sxl transcript potentially encode up to six slightly different polypeptides. All of the protein-coding differences occur outside the previously defined ribonucleoprotein motifs. One class of Sxl mRNAs also includes a second long ORF in the same frame as the first ORF but separated from it by a single ochre codon. The function of this second ORF is unknown. Significant amounts of apparently partially processed Sxl RNAs were observed, consistent with the hypothesis that the regulated Sxl splices occur relatively slowly. Images PMID:1710769

  10. Sex differences in kidney gene expression during the life cycle of F344 rats.

    PubMed

    Kwekel, Joshua C; Desai, Varsha G; Moland, Carrie L; Vijay, Vikrant; Fuscoe, James C

    2013-07-31

    The kidney functions in key physiological processes to filter blood and regulate blood pressure via key molecular transporters and ion channels. Sex-specific differences have been observed in renal disease incidence and progression, as well as acute kidney injury in response to certain drugs. Although advances have been made in characterizing the molecular components involved in various kidney functions, the molecular mechanisms responsible for sex differences are not well understood. We hypothesized that the basal expression levels of genes involved in various kidney functions throughout the life cycle will influence sex-specific susceptibilities to adverse renal events. Whole genome microarray gene expression analysis was performed on kidney samples collected from untreated male and female Fischer 344 (F344) rats at eight age groups between 2 and 104 weeks of age. A combined filtering approach using statistical (ANOVA or pairwise t test, FDR 0.05) and fold-change criteria (>1.5 relative fold change) was used to identify 7,447 unique differentially expressed genes (DEGs). Principal component analysis (PCA) of the 7,447 DEGs revealed sex-related differences in mRNA expression at early (2 weeks), middle (8, 15, and 21 weeks), and late (104 weeks) ages in the rat life cycle. Functional analysis (Ingenuity Pathway Analysis) of these sex-different genes indicated over-representation of specific pathways and networks including renal tubule injury, drug metabolism, and immune cell and inflammatory responses. The mRNAs that code for the qualified urinary protein kidney biomarkers KIM-1, Clu, Tff3, and Lcn2 were also observed to show sex differences. These data represent one of the most comprehensive in-life time course studies to be published, assessing sex differences in global gene expression in the F344 rat kidney. PCA and Venn analyses reveal specific periods of sexually dimorphic gene expression which are associated with functional categories (xenobiotic

  11. Sex differences in kidney gene expression during the life cycle of F344 rats

    PubMed Central

    2013-01-01

    Background The kidney functions in key physiological processes to filter blood and regulate blood pressure via key molecular transporters and ion channels. Sex-specific differences have been observed in renal disease incidence and progression, as well as acute kidney injury in response to certain drugs. Although advances have been made in characterizing the molecular components involved in various kidney functions, the molecular mechanisms responsible for sex differences are not well understood. We hypothesized that the basal expression levels of genes involved in various kidney functions throughout the life cycle will influence sex-specific susceptibilities to adverse renal events. Methods Whole genome microarray gene expression analysis was performed on kidney samples collected from untreated male and female Fischer 344 (F344) rats at eight age groups between 2 and 104 weeks of age. Results A combined filtering approach using statistical (ANOVA or pairwise t test, FDR 0.05) and fold-change criteria (>1.5 relative fold change) was used to identify 7,447 unique differentially expressed genes (DEGs). Principal component analysis (PCA) of the 7,447 DEGs revealed sex-related differences in mRNA expression at early (2 weeks), middle (8, 15, and 21 weeks), and late (104 weeks) ages in the rat life cycle. Functional analysis (Ingenuity Pathway Analysis) of these sex-different genes indicated over-representation of specific pathways and networks including renal tubule injury, drug metabolism, and immune cell and inflammatory responses. The mRNAs that code for the qualified urinary protein kidney biomarkers KIM-1, Clu, Tff3, and Lcn2 were also observed to show sex differences. Conclusions These data represent one of the most comprehensive in-life time course studies to be published, assessing sex differences in global gene expression in the F344 rat kidney. PCA and Venn analyses reveal specific periods of sexually dimorphic gene expression which are associated with

  12. Gene-gene and gene-sex epistatic interactions of DNMT1, DNMT3A and DNMT3B in autoimmune thyroid disease.

    PubMed

    Cai, Tian-Tian; Zhang, Jian; Wang, Xuan; Song, Rong-Hua; Qin, Qiu; Muhali, Fatuma-Said; Zhou, Jiao-Zhen; Xu, Jian; Zhang, Jin-An

    2016-07-30

    The aim of this study was to investigate the associations of DNA methyltransferases (DNMTs) polymorphisms with susceptibility to autoimmune thyroid diseases (AITDs) and to test gene-gene/gene-sex epistasis interactions. Eight single-nucleotide polymorphisms (SNPs) in DNMT1, DNMT3A and DNMT3B were selected and genotyped by multiplex polymerase chain reaction combined with ligase detection reaction method (PCR-LDR). A total of 685 Graves' disease (GD) patients, 353 Hashimoto's thyroiditis (HT) patients and 909 healthy controls were included in the final analysis. Epistasis was tested by additive model, multiplicative model and general multifactor dimensionality reduction (general MDR). Rs2424913 (DNMT3B) and rs2228611 (DNMT1) were associated with susceptibility to AITD and GD in the dominant and overdominant model, respectively (rs2424913: P=0.009 for AITD, P=0.0041 for GD; rs2228611: P=0.035 for AITD, P=0.043 for GD). Multiplicative and multiple high dimensional gene-gene or gene-sex interactions were also observed in this study. We have found evidence for a potential role of rs2424913 (DNMT3B) and rs2228611 (DNMT1) in AITD susceptibility and identified novel gene-gene/gene-sex interactions in AITD. Our study may highlight sex and genes of DNMTs family as contributors to the pathogenesis of AITD.

  13. Skeletal muscle gene expression in response to resistance exercise: sex specific regulation

    PubMed Central

    2010-01-01

    Background The molecular mechanisms underlying the sex differences in human muscle morphology and function remain to be elucidated. The sex differences in the skeletal muscle transcriptome in both the resting state and following anabolic stimuli, such as resistance exercise (RE), might provide insight to the contributors of sexual dimorphism of muscle phenotypes. We used microarrays to profile the transcriptome of the biceps brachii of young men and women who underwent an acute unilateral RE session following 12 weeks of progressive training. Bilateral muscle biopsies were obtained either at an early (4 h post-exercise) or late recovery (24 h post-exercise) time point. Muscle transcription profiles were compared in the resting state between men (n = 6) and women (n = 8), and in response to acute RE in trained exercised vs. untrained non-exercised control muscle for each sex and time point separately (4 h post-exercise, n = 3 males, n = 4 females; 24 h post-exercise, n = 3 males, n = 4 females). A logistic regression-based method (LRpath), following Bayesian moderated t-statistic (IMBT), was used to test gene functional groups and biological pathways enriched with differentially expressed genes. Results This investigation identified extensive sex differences present in the muscle transcriptome at baseline and following acute RE. In the resting state, female muscle had a greater transcript abundance of genes involved in fatty acid oxidation and gene transcription/translation processes. After strenuous RE at the same relative intensity, the time course of the transcriptional modulation was sex-dependent. Males experienced prolonged changes while females exhibited a rapid restoration. Most of the biological processes involved in the RE-induced transcriptional regulation were observed in both males and females, but sex specificity was suggested for several signaling pathways including activation of notch signaling and TGF-beta signaling in females. Sex differences in

  14. Effects of tamoxifen on the sex determination gene and the activation of sex reversal in the developing gonad of mice.

    PubMed

    Yu, Mingxi; Wang, Jingyun; Liu, Wei; Qin, Junwen; Zhou, Quan; Wang, Yongan; Huang, Huihui; Chen, Wenli; Ma, Chao

    2014-07-03

    Tamoxifen, as well as most endocrine-disrupting chemicals, affects the reproductive system and sexual development, but little is known about its disruption of the molecular pathways regulating mammalian sex determination. In fetal mice, the expression levels and pattern of key genes involved in controlling sexually dimorphic balance were analyzed both in vivo and in vitro by using whole-mount in situ hybridization and quantitative-PCR. Developmental tamoxifen exposure induced abnormal up-regulation of the testis differentiation marker Pdfgra in Leydig cells and of Sox9 and Fgf9 in Sertoli cells in XX gonad. Immunohistochemistry analysis confirmed the over-expression of SOX9 protein. Accordingly, the ovary development marker Foxl2 was depressed at both the mRNA and protein levels. The increase in testosterone and the reduction in 17β-estradiol and progesterone were observed by using the in vitro assay with organotypic cultures. Taken together, results indicated that tamoxifen induced the ectopic expression of well-established sex-specific genes during the critical developmental period, thus resulting in abnormal testicular development in the XX gonad of mammals. This study facilitates a better understanding of the molecular mechanisms of antiestrogens and possibly of compounds that interrupt estrogen signaling by other modes of action, and the association with the pathogenesis of human sexual developmental disorders.

  15. Prioritizing genes of potential relevance to diseases affected by sex hormones: an example of Myasthenia Gravis

    PubMed Central

    Kaur, Mandeep; Schmeier, Sebastian; MacPherson, Cameron R; Hofmann, Oliver; Hide, Winston A; Taylor, Stephen; Willcox, Nick; Bajic, Vladimir B

    2008-01-01

    Background About 5% of western populations are afflicted by autoimmune diseases many of which are affected by sex hormones. Autoimmune diseases are complex and involve many genes. Identifying these disease-associated genes contributes to development of more effective therapies. Also, association studies frequently imply genomic regions that contain disease-associated genes but fall short of pinpointing these genes. The identification of disease-associated genes has always been challenging and to date there is no universal and effective method developed. Results We have developed a method to prioritize disease-associated genes for diseases affected strongly by sex hormones. Our method uses various types of information available for the genes, but no information that directly links genes with the disease. It generates a score for each of the considered genes and ranks genes based on that score. We illustrate our method on early-onset myasthenia gravis (MG) using genes potentially controlled by estrogen and localized in a genomic segment (which contains the MHC and surrounding region) strongly associated with MG. Based on the considered genomic segment 283 genes are ranked for their relevance to MG and responsiveness to estrogen. The top three ranked genes, HLA-G, TAP2 and HLA-DRB1, are implicated in autoimmune diseases, while TAP2 is associated with SNPs characteristic for MG. Within the top 35 prioritized genes our method identifies 90% of the 10 already known MG-associated genes from the considered region without using any information that directly links genes to MG. Among the top eight genes we identified HLA-G and TUBB as new candidates. We show that our ab-initio approach outperforms the other methods for prioritizing disease-associated genes. Conclusion We have developed a method to prioritize disease-associated genes under the potential control of sex hormones. We demonstrate the success of this method by prioritizing the genes localized in the MHC and

  16. Sex-Specificity of Mineralocorticoid Target Gene Expression during Renal Development, and Long-Term Consequences

    PubMed Central

    Dumeige, Laurence; Storey, Caroline; Decourtye, Lyvianne; Nehlich, Melanie; Lhadj, Christophe; Viengchareun, Say; Kappeler, Laurent; Lombès, Marc; Martinerie, Laetitia

    2017-01-01

    Sex differences have been identified in various biological processes, including hypertension. The mineralocorticoid signaling pathway is an important contributor to early arterial hypertension, however its sex-specific expression has been scarcely studied, particularly with respect to the kidney. Basal systolic blood pressure (SBP) and heart rate (HR) were measured in adult male and female mice. Renal gene expression studies of major players of mineralocorticoid signaling were performed at different developmental stages in male and female mice using reverse transcription quantitative PCR (RT-qPCR), and were compared to those of the same genes in the lung, another mineralocorticoid epithelial target tissue that regulates ion exchange and electrolyte balance. The role of sex hormones in the regulation of these genes was also investigated in differentiated KC3AC1 renal cells. Additionally, renal expression of the 11 β-hydroxysteroid dehydrogenase type 2 (11βHSD2) protein, a regulator of mineralocorticoid specificity, was measured by immunoblotting and its activity was indirectly assessed in the plasma using liquid-chromatography coupled to mass spectrometry in tandem (LC-MSMS) method. SBP and HR were found to be significantly lower in females compared to males. This was accompanied by a sex- and tissue-specific expression profile throughout renal development of the mineralocorticoid target genes serum and glucocorticoid-regulated kinase 1 (Sgk1) and glucocorticoid-induced leucine zipper protein (Gilz), together with Hsd11b2, Finally, the implication of sex hormones in this sex-specific expression profile was demonstrated in vitro, most notably for Gilz mRNA expression. We demonstrate a tissue-specific, sex-dependent and developmentally-regulated pattern of expression of the mineralocorticoid pathway that could have important implications in physiology and pathology. PMID:28230786

  17. Molecular analyses of circadian gene variants reveal sex-dependent links between depression and clocks.

    PubMed

    Shi, S-q; White, M J; Borsetti, H M; Pendergast, J S; Hida, A; Ciarleglio, C M; de Verteuil, P A; Cadar, A G; Cala, C; McMahon, D G; Shelton, R C; Williams, S M; Johnson, C H

    2016-03-01

    An extensive literature links circadian irregularities and/or sleep abnormalities to mood disorders. Despite the strong genetic component underlying many mood disorders, however, previous genetic associations between circadian clock gene variants and major depressive disorder (MDD) have been weak. We applied a combined molecular/functional and genetic association approach to circadian gene polymorphisms in sex-stratified populations of control subjects and case subjects suffering from MDD. This approach identified significant sex-dependent associations of common variants of the circadian clock genes hClock, hPer3 and hNpas2 with major depression and demonstrated functional effects of these polymorphisms on the expression or activity of the hCLOCK and hPER3 proteins, respectively. In addition, hCLOCK expression is affected by glucocorticoids, consistent with the sex-dependency of the genetic associations and the modulation of glucocorticoid-mediated stress response, providing a mechanism by which the circadian clock controls outputs that may affect psychiatric disorders. We conclude that genetic polymorphisms in circadian genes (especially hClock and hPer3, where functional assays could be tested) influence risk of developing depression in a sex- and stress-dependent manner. These studies support a genetic connection between circadian disruption and mood disorders, and confirm a key connection between circadian gene variation and major depression.

  18. Molecular analyses of circadian gene variants reveal sex-dependent links between depression and clocks

    PubMed Central

    Shi, S-q; White, M J; Borsetti, H M; Pendergast, J S; Hida, A; Ciarleglio, C M; de Verteuil, P A; Cadar, A G; Cala, C; McMahon, D G; Shelton, R C; Williams, S M; Johnson, C H

    2016-01-01

    An extensive literature links circadian irregularities and/or sleep abnormalities to mood disorders. Despite the strong genetic component underlying many mood disorders, however, previous genetic associations between circadian clock gene variants and major depressive disorder (MDD) have been weak. We applied a combined molecular/functional and genetic association approach to circadian gene polymorphisms in sex-stratified populations of control subjects and case subjects suffering from MDD. This approach identified significant sex-dependent associations of common variants of the circadian clock genes hClock, hPer3 and hNpas2 with major depression and demonstrated functional effects of these polymorphisms on the expression or activity of the hCLOCK and hPER3 proteins, respectively. In addition, hCLOCK expression is affected by glucocorticoids, consistent with the sex-dependency of the genetic associations and the modulation of glucocorticoid-mediated stress response, providing a mechanism by which the circadian clock controls outputs that may affect psychiatric disorders. We conclude that genetic polymorphisms in circadian genes (especially hClock and hPer3, where functional assays could be tested) influence risk of developing depression in a sex- and stress-dependent manner. These studies support a genetic connection between circadian disruption and mood disorders, and confirm a key connection between circadian gene variation and major depression. PMID:26926884

  19. Targeted Deletion of Btg1 and Btg2 Results in Homeotic Transformation of the Axial Skeleton.

    PubMed

    Tijchon, Esther; van Ingen Schenau, Dorette; van Opzeeland, Fred; Tirone, Felice; Hoogerbrugge, Peter M; Van Leeuwen, Frank N; Scheijen, Blanca

    2015-01-01

    Btg1 and Btg2 encode highly homologous proteins that are broadly expressed in different cell lineages, and have been implicated in different types of cancer. Btg1 and Btg2 have been shown to modulate the function of different transcriptional regulators, including Hox and Smad transcription factors. In this study, we examined the in vivo role of the mouse Btg1 and Btg2 genes in specifying the regional identity of the axial skeleton. Therefore, we examined the phenotype of Btg1 and Btg2 single knockout mice, as well as novel generated Btg1-/-;Btg2-/- double knockout mice, which were viable, but displayed a non-mendelian inheritance and smaller litter size. We observed both unique and overlapping phenotypes reminiscent of homeotic transformation along the anterior-posterior axis in the single and combined Btg1 and Btg2 knockout animals. Both Btg1-/- and Btg2-/- mice displayed partial posterior transformation of the seventh cervical vertebra, which was more pronounced in Btg1-/-;Btg2-/- mice, demonstrating that Btg1 and Btg2 act in synergy. Loss of Btg2, but not Btg1, was sufficient for complete posterior transformation of the thirteenth thoracic vertebra to the first lumbar vertebra. Moreover, Btg2-/- animals displayed complete posterior transformation of the sixth lumbar vertebra to the first sacral vertebra, which was only partially present at a low frequency in Btg1-/- mice. The Btg1-/-;Btg2-/- animals showed an even stronger phenotype, with L5 to S1 transformation. Together, these data show that both Btg1 and Btg2 are required for normal vertebral patterning of the axial skeleton, but each gene contributes differently in specifying the identity along the anterior-posterior axis of the skeleton.

  20. Targeted Deletion of Btg1 and Btg2 Results in Homeotic Transformation of the Axial Skeleton

    PubMed Central

    van Opzeeland, Fred; Tirone, Felice; Hoogerbrugge, Peter M.; Van Leeuwen, Frank N.; Scheijen, Blanca

    2015-01-01

    Btg1 and Btg2 encode highly homologous proteins that are broadly expressed in different cell lineages, and have been implicated in different types of cancer. Btg1 and Btg2 have been shown to modulate the function of different transcriptional regulators, including Hox and Smad transcription factors. In this study, we examined the in vivo role of the mouse Btg1 and Btg2 genes in specifying the regional identity of the axial skeleton. Therefore, we examined the phenotype of Btg1 and Btg2 single knockout mice, as well as novel generated Btg1-/-;Btg2-/- double knockout mice, which were viable, but displayed a non-mendelian inheritance and smaller litter size. We observed both unique and overlapping phenotypes reminiscent of homeotic transformation along the anterior-posterior axis in the single and combined Btg1 and Btg2 knockout animals. Both Btg1-/- and Btg2-/- mice displayed partial posterior transformation of the seventh cervical vertebra, which was more pronounced in Btg1-/-;Btg2-/- mice, demonstrating that Btg1 and Btg2 act in synergy. Loss of Btg2, but not Btg1, was sufficient for complete posterior transformation of the thirteenth thoracic vertebra to the first lumbar vertebra. Moreover, Btg2-/- animals displayed complete posterior transformation of the sixth lumbar vertebra to the first sacral vertebra, which was only partially present at a low frequency in Btg1-/- mice. The Btg1-/-;Btg2-/- animals showed an even stronger phenotype, with L5 to S1 transformation. Together, these data show that both Btg1 and Btg2 are required for normal vertebral patterning of the axial skeleton, but each gene contributes differently in specifying the identity along the anterior-posterior axis of the skeleton. PMID:26218146

  1. Transcriptome profiling in the damselfly Ischnura elegans identifies genes with sex-biased expression.

    PubMed

    Chauhan, Pallavi; Wellenreuther, Maren; Hansson, Bengt

    2016-12-01

    Sexual dimorphism occurs widely across the animal kingdom and has profound effects on evolutionary trajectories. Here, we investigate sex-specific gene expression in Ischnura elegans (Odonata: dragonflies and damselflies), a species with pronounced sexual differences including a female-limited colour polymorphism with two female-like gynochrome morphs and one male-mimicking, androchrome morph. Whole-organism transcriptome profiling and sex-biased gene expression analysis was conducted on adults of both sexes (pooling all females as well as separating the three morphs) to gain insights into genes and pathways potentially associated with sexual development and sexual conflict. The de novo transcriptome assembly was of high quality and completeness (54 k transcripts; 99.6% CEGMA score; 55% annotated). We identified transcripts of several relevant pathways, including transcripts involved in sex determination, hormone biosynthesis, pigmentation and innate immune signalling. A total of 1,683 genes were differentially expressed (DE) between males and all females (1,173 were female-biased; 510 male-biased). The DE genes were associated with sex-specific physiological and reproductive processes, olfaction, pigmentation (ommochrome and melanin), hormone (ecdysone) biosynthesis and innate immunity signalling pathways. Comparisons between males and each female morph category showed that the gynochromes differed more from males than the androchrome morph. This is the first study to characterize sex-biased gene expression in odonates, one of the most ancient extant insect orders. Comparison between I. elegans sexes revealed expression differences in several genes related to sexual differences in behaviour and development as well as morphology. The differential expression of several olfactory genes suggests interesting sexual components in the detection of odours, pheromones and environmental volatiles. Up-regulation of pigmentation pathways in females indicates a prominent role

  2. The elusive action of sex-determining genes: mitochondria to the rescue?

    PubMed

    Mittwoch, Ursula

    2004-06-07

    According to the accepted dogma of mammalian sex determination, the Y-linked gene SRY initiates male development by inducing hitherto uncommitted somatic cells of the fetal gonad to develop into Sertoli cells. However, it has become evident that the correct functioning of an increasing number of genes on other chromosomes is required for testicular organogenesis. They include the SRY-related gene, SOX9, which plays important roles in both sex determination and chondrogenesis, as well as genes responsible for the production of growth factors, i.e. fibroblast growth factor 9, platelet derived growth factor A, and the members of the insulin-receptor family of genes. It is known, moreover, that differences between the sexes begin to develop long before the differentiation of Sertoli cells, including an increase in gonadal size and cell proliferation, and accelerated development of XY embryos at early pre-implantation stages. There is also evidence of transcription of Y-linked, and of X-linked, genes and of an enhanced metabolic rate in XY embryos. Furthermore, the condition of true hermaphroditism does not fit into a simple genotype/phenotype relationship. The proposal that "testis-determining" genes act by increasing metabolic rates rather than directly determining Sertoli cell differentiation can account for a number of observations that do not fit the current model, including pregonadal sex differences, the activity of the same gene in different organ systems, and the frequent co-existence of sexual and somatic abnormalities. It also sheds light on the pervasive differences between metabolic rates of mammalian males and females, while the facts of true hermaphroditism can be viewed as remnants of temperature-dependent sex determination in ectothermic vertebrates. Growing interest in mitochondria, which play a central role in the provision of energy to eukaryotic cells, makes a shift of paradigm from gonadal histology to energy metabolism timely, particularly since

  3. Genetic variants in sex hormone metabolic pathway genes and risk of esophageal squamous cell carcinoma.

    PubMed

    Hyland, Paula L; Freedman, Neal D; Hu, Nan; Tang, Ze-Zhong; Wang, Lemin; Wang, Chaoyu; Ding, Ti; Fan, Jin-Hu; Qiao, You-Lin; Golozar, Asieh; Wheeler, William; Yu, Kai; Yuenger, Jeff; Burdett, Laurie; Chanock, Stephen J; Dawsey, Sanford M; Tucker, Margaret A; Goldstein, Alisa M; Abnet, Christian C; Taylor, Philip R

    2013-05-01

    In China, esophageal cancer is the fourth leading cause of cancer death where essentially all cases are histologically esophageal squamous cell carcinoma (ESCC), in contrast to esophageal adenocarcinoma in the West. Globally, ESCC is 2.4 times more common among men than women and recently it has been suggested that sex hormones may be associated with the risk of ESCC. We examined the association between genetic variants in sex hormone metabolic genes and ESCC risk in a population from north central China with high-incidence rates. A total of 1026 ESCC cases and 1452 controls were genotyped for 797 unique tag single-nucleotide polymorphisms (SNPs) in 51 sex hormone metabolic genes. SNP-, gene- and pathway-based associations with ESCC risk were evaluated using unconditional logistic regression adjusted for age, sex and geographical location and the adaptive rank truncated product (ARTP) method. Statistical significance was determined through use of permutation for pathway- and gene-based associations. No associations were observed for the overall sex hormone metabolic pathway (P = 0.14) or subpathways (androgen synthesis: P = 0.30, estrogen synthesis: P = 0.15 and estrogen removal: P = 0.19) with risk of ESCC. However, six individual genes (including SULT2B1, CYP1B1, CYP3A7, CYP3A5, SHBG and CYP11A1) were significantly associated with ESCC risk (P < 0.05). Our examination of genetic variation in the sex hormone metabolic pathway is consistent with a potential association with risk of ESCC. These positive findings warrant further evaluation in relation to ESCC risk and replication in other populations.

  4. Differential expression analysis of genes involved in high-temperature induced sex differentiation in Nile tilapia.

    PubMed

    Li, Chun Ge; Wang, Hui; Chen, Hong Ju; Zhao, Yan; Fu, Pei Sheng; Ji, Xiang Shan

    2014-01-01

    Nowadays, high temperature effects on the molecular pathways during sex differentiation in teleosts need to be deciphered. In this study, a systematic differential expression analysis of genes involved in high temperature-induced sex differentiation was done in the Nile tilapia gonad and brain. Our results showed that high temperature caused significant down-regulation of CYP19A1A in the gonad of both sexes in induction group, and FOXL2 in the ovary of the induction group. The expressions of GTHα, LHβ and ERα were also significantly down-regulated in the brain of both sexes in the induction and recovery groups. On the contrary, the expression of CYP11B2 was significantly up-regulated in the ovary, but not in the testis in both groups. Spearman rank correlation analysis showed that there are significant correlations between the expressions of CYP19A1A, FOXL2, or DMRT1 in the gonads and the expression of some genes in the brain. Another result in this study showed that high temperature up-regulated the expression level of DNMT1 in the testis of the induction group, and DNMT1 and DNMT3A in the female brain of both groups. The expression and correlation analysis of HSPs showed that high temperature action on tilapia HSPs might indirectly induce the expression changes of sex differentiation genes in the gonads. These findings provide new insights on TSD and suggest that sex differentiation related genes, heat shock proteins, and DNA methylation genes are new candidates for studying TSD in fish species.

  5. Genetic variants in sex hormone metabolic pathway genes and risk of esophageal squamous cell carcinoma

    PubMed Central

    Hyland, Paula L.

    2013-01-01

    In China, esophageal cancer is the fourth leading cause of cancer death where essentially all cases are histologically esophageal squamous cell carcinoma (ESCC), in contrast to esophageal adenocarcinoma in the West. Globally, ESCC is 2.4 times more common among men than women and recently it has been suggested that sex hormones may be associated with the risk of ESCC. We examined the association between genetic variants in sex hormone metabolic genes and ESCC risk in a population from north central China with high-incidence rates. A total of 1026 ESCC cases and 1452 controls were genotyped for 797 unique tag single-nucleotide polymorphisms (SNPs) in 51 sex hormone metabolic genes. SNP-, gene- and pathway-based associations with ESCC risk were evaluated using unconditional logistic regression adjusted for age, sex and geographical location and the adaptive rank truncated product (ARTP) method. Statistical significance was determined through use of permutation for pathway- and gene-based associations. No associations were observed for the overall sex hormone metabolic pathway (P = 0.14) or subpathways (androgen synthesis: P = 0.30, estrogen synthesis: P = 0.15 and estrogen removal: P = 0.19) with risk of ESCC. However, six individual genes (including SULT2B1, CYP1B1, CYP3A7, CYP3A5, SHBG and CYP11A1) were significantly associated with ESCC risk (P < 0.05). Our examination of genetic variation in the sex hormone metabolic pathway is consistent with a potential association with risk of ESCC. These positive findings warrant further evaluation in relation to ESCC risk and replication in other populations. PMID:23358850

  6. Sex-based differences in gene expression in hippocampus following postnatal lead exposure.

    PubMed

    Schneider, J S; Anderson, D W; Sonnenahalli, H; Vadigepalli, R

    2011-10-15

    The influence of sex as an effect modifier of childhood lead poisoning has received little systematic attention. Considering the paucity of information available concerning the interactive effects of lead and sex on the brain, the current study examined the interactive effects of lead and sex on gene expression patterns in the hippocampus, a structure involved in learning and memory. Male or female rats were fed either 1500 ppm lead-containing chow or control chow for 30 days beginning at weaning.Blood lead levels were 26.7±2.1 μg/dl and 27.1±1.7 μg/dl for females and males, respectively. The expression of 175 unique genes was differentially regulated between control male and female rats. A total of 167 unique genes were differentially expressed in response to lead in either males or females. Lead exposure had a significant effect without a significant difference between male and female responses in 77 of these genes. In another set of 71 genes, there were significant differences in male vs. female response. A third set of 30 genes was differentially expressed in opposite directions in males vs. females, with the majority of genes expressed at a lower level in females than in males. Highly differentially expressed genes in males and females following lead exposure were associated with diverse biological pathways and functions. These results show that a brief exposure to lead produced significant changes in expression of a variety of genes in the hippocampus and that the response of the brain to a given lead exposure may vary depending on sex. Copyright © 2011 Elsevier Inc. All rights reserved.

  7. Sex Steroids Regulate Expression of Genes Containing Long Interspersed Elements-1s in Breast Cancer Cells.

    PubMed

    Chaiwongwatanakul, Saichon; Yanatatsaneejit, Pattamawadee; Tongsima, Sissades; Mutirangura, Apiwat; Boonyaratanakornkit, Viroj

    2016-01-01

    Long interspersed elements-1s (LINE-1s) are dispersed all over the human genome. There is evidence that hypomethylation of LINE-1s and levels of sex steroids regulate gene expression leading to cancer development. Here, we compared mRNA levels of genes containing an intragenic LINE-1 in breast cancer cells treated with various sex steroids from Gene Expression Omnibus (GEO), with the gene expression database using chi-square analysis (http://www.ncbi.nlm.nih.gov/geo). We evaluated whether sex steroids influence expression of genes containing an intragenic LINE-1. Three sex steroids at various concentrations, 1 and 10 nM estradiol (E2), 10 nM progesterone (PG) and 10 nM androgen (AN), were assessed. In breast cancer cells treated with 1 or 10 nM E2, a significant percentage of genes containing an intragenic LINE-1 were down-regulated. A highly significant percentage of E2-regulated genes containing an intragenic LINE-1 was down-regulated in cells treated with 1 nM E2 for 3 hours (<3.70E-25; OR=1.91; 95% CI=2.16-1.69). Similarly, high percentages of PG or AN- regulated genes containing an intragenic LINE-1 were also down-regulated in cells treated with 10 nM PG or 10 nM AN for 16 hr (p=9.53E-06; OR=1.65; 95% CI=2.06-1.32 and p=3.81E-14; OR=2.01; 95% CI=2.42-1.67). Interestingly, a significant percentage of AN-regulated genes containing an intragenic LINE-1 was up-regulated in cells treated with 10 nM AN for 16 hr (p=4.03E-02; OR=1.40; 95% CI=1.95-1.01). These findings suggest that intragenic LINE-1s may play roles in sex steroid mediated gene expression in breast cancer cells, which could have significant implications for the development and progression of sex steroid-dependent cancers.

  8. Sexually dimorphic expression of the sex chromosome-linked genes cntfa and pdlim3a in the medaka brain.

    PubMed

    Maehiro, Sayaka; Takeuchi, Akio; Yamashita, Junpei; Hiraki, Towako; Kawabata, Yukika; Nakasone, Kiyoshi; Hosono, Kohei; Usami, Takeshi; Paul-Prasanth, Bindhu; Nagahama, Yoshitaka; Oka, Yoshitaka; Okubo, Kataaki

    2014-02-28

    In vertebrates, sex differences in the brain have been attributed to differences in gonadal hormone secretion; however, recent evidence in mammals and birds shows that sex chromosome-linked genes, independent of gonadal hormones, also mediate sex differences in the brain. In this study, we searched for genes that were differentially expressed between the sexes in the brain of a teleost fish, medaka (Oryzias latipes), and identified two sex chromosome genes with male-biased expression, cntfa (encoding ciliary neurotrophic factor a) and pdlim3a (encoding PDZ and LIM domain 3 a). These genes were found to be located 3-4 Mb from and on opposite sides of the Y chromosome-specific region containing the sex-determining gene (the medaka X and Y chromosomes are genetically identical, differing only in this region). The male-biased expression of both genes was evident prior to the onset of sexual maturity. Sex-reversed XY females, as well as wild-type XY males, had more pronounced expression of these genes than XX males and XX females, indicating that the Y allele confers higher expression than the X allele for both genes. In addition, their expression was affected to some extent by sex steroid hormones, thereby possibly serving as focal points of the crosstalk between the genetic and hormonal pathways underlying brain sex differences. Given that sex chromosomes of lower vertebrates, including teleost fish, have evolved independently in different genera or species, sex chromosome genes with sexually dimorphic expression in the brain may contribute to genus- or species-specific sex differences in a variety of traits. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Transcription Regulation of Sex-Biased Genes during Ontogeny in the Malaria Vector Anopheles gambiae

    PubMed Central

    Windbichler, Nikolai; Papathanos, Philippos-Aris; Nolan, Tony; Dottorini, Tania; Rizzi, Ermanno; Christophides, George K.; Crisanti, Andrea

    2011-01-01

    In Anopheles gambiae, sex-regulated genes are responsible for controlling gender dimorphism and are therefore crucial in determining the ability of female mosquitoes to transmit human malaria. The identification and functional characterization of these genes will shed light on the sexual development and maturation of mosquitoes and provide useful targets for genetic control measures aimed at reducing mosquito fertility and/or distorting the sex ratio. We conducted a genome wide transcriptional analysis of sex-regulated genes from early developmental stages through adulthood combined with functional screening of novel gonadal genes. Our results demonstrate that the male-biased genes undergo a major transcription turnover starting from larval stages to adulthood. The male biased genes at the adult stage include a significant high number of unique sequences compared to the rest of the genome. This is in contrast to female-biased genes that are much more conserved and are mainly activated during late developmental stages. The high frequency of unique sequences would indicate that male-biased genes evolve more rapidly than the rest of the genome. This finding is particularly intriguing because A. gambiae is a strictly female monogamous species suggesting that driving forces in addition to sperm competition must account for the rapid evolution of male-biased genes. We have also identified and functionally characterized a number of previously unknown A. gambiae testis- and ovary-specific genes. Two of these genes, zero population growth and a suppressor of defective silencing 3 domain of the histone deacetylase co-repressor complex, were shown to play a key role in gonad development. PMID:21738713

  10. Transcriptional sexual dimorphism in elongating bovine embryos: implications for XCI and sex determination genes.

    PubMed

    Bermejo-Alvarez, P; Rizos, D; Lonergan, P; Gutierrez-Adan, A

    2011-06-01

    Sex chromosome transcripts can lead to a broad transcriptional sexual dimorphism in the absence of concomitant or previous exposure to sex hormones, especially when X-chromosome inactivation (XCI) is not complete. XCI timing has been suggested to differ greatly among species, and in bovine, most of the X-linked transcripts are upregulated in female blastocysts. To determine the timing of XCI, we analyzed in day 14 bovine embryos the sexual dimorphic transcription of seven X-linked genes known to be upregulated in female blastocysts (X24112, brain-expressed X-linked 2 (BEX2), ubiquitin-conjugating enzyme E2A (UBE2A), glucose-6-phosphate dehydrogenase (G6PD), brain-expressed X-linked 1 (BEX1), calpain 6 (CAPN6), and spermidine/spermine N-acetyltransferase 1 (SAT1)). The transcription of five genes whose expression differs between sexes at the blastocyst stage (DNMT3A, interferon tau (IFNT2), glutathione S-transferase mu 3 (GSTM3), progesterone receptor membrane component 1 (PGRMC1), and laminin alpha 1 (LAMA1)) and four genes related with sex determination (Wilms tumor 1 (WT1), gata binding protein 4 (GATA4), zinc finger protein multitype 2 (ZFPM2), and DMRT1) was also analyzed to determine the evolution of transcriptional sexual dimorphism. The expression level of five X-linked transcripts was effectively equalized among sexes suggesting that, in cattle, a substantial XCI occurs during the period between blastocyst hatching and initiation of elongation, although UBE2A and SAT1 displayed significant transcriptional differences. Similarly, sexual dimorphism was also reduced for autosomal genes with only DNMT3A and IFNT2 exhibiting sex-related differences. Among the genes potentially involved in sex determination, Wilms tumor 1 (WT1) was significantly upregulated in males and GATA4 in females, whereas no differences were observed for ZFPM2 and DMRT1. In conclusion, a major XCI occurred between the blastocyst and early elongation stages leading to a reduction in the

  11. The roles of Dmrt (Double sex/Male-abnormal-3 Related Transcription factor) genes in sex determination and differentiation mechanisms: Ubiquity and diversity across the animal kingdom.

    PubMed

    Picard, Marion Anne-Lise; Cosseau, Céline; Mouahid, Gabriel; Duval, David; Grunau, Christoph; Toulza, Ève; Allienne, Jean-François; Boissier, Jérôme

    2015-07-01

    The Dmrt (Double sex/Male-abnormal-3 Related Transcription factor) genes have been intensively studied because they represent major transcription factors in the pathways governing sex determination and differentiation. These genes have been identified in animal groups ranging from cnidarians to mammals, and some of the genes functionally studied. Here, we propose to analyze (i) the presence/absence of various Dmrt gene groups in the different taxa across the animal kingdom; (ii) the relative expression levels of the Dmrt genes in each sex; (iii) the specific spatial (by organ) and temporal (by developmental stage) variations in gene expression. This review considers non-mammalian animals at all levels of study (i.e. no particular importance is given to animal models), and using all types of sexual strategy (hermaphroditic or gonochoric) and means of sex determination (i.e. genetic or environmental). To conclude this global comparison, we offer an analysis of the DM domains conserved among the different DMRT proteins, and propose a general sex-specific pattern for each member of the Dmrt gene family.

  12. Evidence that sex chromosome genes affect sexual differentiation of female sexual behavior.

    PubMed

    Grgurevic, Neza; Büdefeld, Tomaz; Spanic, Tanja; Tobet, Stuart A; Majdic, Gregor

    2012-05-01

    Female receptivity including the immobile hormone-dependent lordosis posture is essential for successful reproduction in rodents. It is well documented that lordosis is organized during the perinatal period when the actions of androgens decrease the males' ability to display this behavior in adulthood. Conversely the absence of androgens, and the presence of low levels of prepubertal estrogens, preserve circuitry that regulates this behavior in females. The current study set out to determine whether sex chromosomal genes are involved in the differentiation of this behavior. An agonadal mouse model was used to test this hypothesis. The SF-1 gene (Nr5a1) is required for development of gonads and adrenal glands, and knockout mice are consequently not exposed to endogenous gonadal steroids. Thus contributions of sex chromosome genes can be disassociated from the actions of estrogens. Use of this model reveals a direct genetic contribution from sex chromosomes in the display of lordosis and other female-typical sexual behavior patterns. It is likely that the concentrations of gonadal steroids present during normal male development modify the actions of sex chromosome genes on the potential to display female sexual behavior. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Sex Differences in Spatial Ability: The X-Linked Gene Theory.

    ERIC Educational Resources Information Center

    Blatter, Patricia

    1982-01-01

    Among the many theories attempting to explain sex differences in spatial ability, one of the most highly researched is the X-linked recessive gene theory. This is a review of the major research done on that theory and shows the conflicting nature of the results. (Author)

  14. Sex Differences in Spatial Ability: The X-Linked Gene Theory.

    ERIC Educational Resources Information Center

    Blatter, Patricia

    1982-01-01

    Among the many theories attempting to explain sex differences in spatial ability, one of the most highly researched is the X-linked recessive gene theory. This is a review of the major research done on that theory and shows the conflicting nature of the results. (Author)

  15. A Duplicated, Truncated amh Gene Is Involved in Male Sex Determination in an Old World Silverside.

    PubMed

    Bej, Dilip Kumar; Miyoshi, Kaho; Hattori, Ricardo S; Strüssmann, Carlos A; Yamamoto, Yoji

    2017-08-07

    A master sex-determining gene, the Y chromosome-linked anti-Müllerian hormone (amhy) gene, has been described in two New World atheriniform species but little is known on the distribution, evolution, and function(s) of this gene in other Atheriniformes. Interestingly, amhy has been found to coexist with temperature-dependent sex determination (TSD), providing a unique opportunity to explore the interplay between genotypic and environmental sex determination. In this study, the search for an amhy homolog was extended to an Old World atheriniform, the cobaltcap silverside Hypoatherina tsurugae (Atherinidae). The full sequences, including the coding and noncoding regions, of the autosomal amh (amha) and a putative amhy were obtained. The deduced Amha and Amhy proteins comprised 511 and 340 amino acids (aa), respectively. PCR analysis with genomic DNA from wild adults and from laboratory-reared juveniles revealed a high, but not complete association of ∼95% between amhy and maleness. The spatiotemporal expression of amhy and amha during gonadal sex differentiation was analyzed by qRT-PCR and in situ hybridization (ISH). amhy transcription (in amhy-positive larvae) started before and peaked during histological differentiation of the gonads whereas amha was negligible during the same period in both genotypes. These results demonstrate that the amhy, although with some structural differences in relation to the amhy of some New World atheriniforms, is strongly associated with maleness and probably important for testicular development in this Old World atheriniform. Thus, amhy is a candidate sex determination gene in cobaltcap silverside and it will be key to scrutinize the mechanism of sex determination in this species. Copyright © 2017 Bej et al.

  16. De novo transcriptome sequencing to identify the sex-determination genes in Hyriopsis schlegelii.

    PubMed

    Shi, Jianwu; Hong, Yijiang; Sheng, Junqing; Peng, Kou; Wang, Junhua

    2015-01-01

    This study presents the first analysis of expressed transcripts in the spermary and ovary of Hyriopsis schlegelii (H. schlegelii). A total of 132,055 unigenes were obtained and 31,781 of these genes were annotated. In addition, 19,511 upregulated and 25,911 downregulated unigenes were identified in the spermary. Ten sex-determination genes were selected and further analyzed by real-time PCR. In addition, mammalian genes reported to govern sex-determination pathways, including Sry, Dmrt1, Dmrt2, Sox9, GATA4, and WT1 in males and Wnt4, Rspo1, Foxl2, and β-catenin in females, were also identified in H. schlegelii. These results suggest that H. schlegelii and mammals use similar gene regulatory mechanisms to control sex determination. Moreover, genes associated with dosage compensation mechanisms, such as Msl1, Msl2, and Msl3, and hermaphrodite phenotypes, such as Tra-1, Tra-2α, Tra-2β, Fem1A, Fem1B, and Fem1C, were also identified in H. schlegelii. The identification of these genes indicates that diverse regulatory mechanisms regulate sexual polymorphism in H. schlegelii.

  17. Deficit of mitonuclear genes on the human X chromosome predates sex chromosome formation.

    PubMed

    Dean, Rebecca; Zimmer, Fabian; Mank, Judith E

    2015-01-29

    Two taxa studied to date, the therian mammals and Caenorhabditis elegans, display underrepresentations of mitonuclear genes (mt-N genes, nuclear genes whose products are imported to and act within the mitochondria) on their X chromosomes. This pattern has been interpreted as the result of sexual conflict driving mt-N genes off of the X chromosome. However, studies in several other species have failed to detect a convergent biased distribution of sex-linked mt-N genes, leading to questions over the generality of the role of sexual conflict in shaping the distribution of mt-N genes. Here we tested whether mt-N genes moved off of the therian X chromosome following sex chromosome formation, consistent with the role of sexual conflict, or whether the paucity of mt-N genes on the therian X is a chance result of an underrepresentation on the ancestral regions that formed the X chromosome. We used a synteny-based approach to identify the ancestral regions in the platypus and chicken genomes that later formed the therian X chromosome. We then quantified the movement of mt-N genes on and off of the X chromosome and the distribution of mt-N genes on the human X and ancestral X regions. We failed to find an excess of mt-N gene movement off of the X. The bias of mt-N genes on ancestral therian X chromosomes was also not significantly different from the biases on the human X. Together our results suggest that, rather than conflict driving mt-N genes off of the mammalian X, random biases on chromosomes that formed the X chromosome could explain the paucity of mt-N genes in the therian lineage.

  18. Selection and evaluation of reference genes for analysis of mouse (Mus musculus) sex-dimorphic brain development

    PubMed Central

    Cheung, Tanya T.; Weston, Mitchell K.

    2017-01-01

    The development of the brain is sex-dimorphic, and as a result so are many neurological disorders. One approach for studying sex-dimorphic brain development is to measure gene expression in biological samples using RT-qPCR. However, the accuracy and consistency of this technique relies on the reference gene(s) selected. We analyzed the expression of ten reference genes in male and female samples over three stages of brain development, using popular algorithms NormFinder, GeNorm and Bestkeeper. The top ranked reference genes at each time point were further used to quantify gene expression of three sex-dimorphic genes (Wnt10b, Xist and CYP7B1). When comparing gene expression between the sexes expression at specific time points the best reference gene combinations are: Sdha/Pgk1 at E11.5, RpL38/Sdha E12.5, and Actb/RpL37 at E15.5. When studying expression across time, the ideal reference gene(s) differs with sex. For XY samples a combination of Actb/Sdha. In contrast, when studying gene expression across developmental stage with XX samples, Sdha/Gapdh were the top reference genes. Our results identify the best combination of two reference genes when studying male and female brain development, and emphasize the importance of selecting the correct reference genes for comparisons between developmental stages. PMID:28133578

  19. Influence of Sex on Basal and Dickkopf-1 Regulated Gene Expression in the Bovine Morula.

    PubMed

    Denicol, Anna C; Leão, Beatriz C S; Dobbs, Kyle B; Mingoti, Gisele Z; Hansen, Peter J

    2015-01-01

    Sex affects function of the developing mammalian embryo as early as the preimplantation period. There were two goals of the current objective. The first was to determine the degree and nature of differences in gene expression between female and male embryos in the cow at the morula stage of development. The second objective was to determine whether DKK1, a molecule known to alter differentiation of the blastocyst, would affect gene expression differently for female and male morulae. In Experiment 1, female and male embryos were treated with DKK1 at Day 5 after insemination. Morulae were harvested 24 h after treatment, pooled in groups of 20 for microarray analysis and RNA subjected to analysis of gene expression by microarray hybridization. There were 662 differentially expressed genes between females and males and 128 of these genes had a fold change ≥ 1.5 between the two sexes. Of the genes upregulated in females, 49.5% were located in the X chromosome. Functional analysis predicted that cell survival was greater in female embryos. Experiment 2 involved a similar design except that transcripts for 12 genes previously reported to be affected by sex, DKK1 or the interaction were quantified by quantitative polymerase chain reaction. Expression of all genes tested that were affected by sex in experiment 1 was affected in a similar manner in Experiment 2. In contrast, effects of DKK1 on gene expression were largely not repeatable in Experiment 2. The exception was for the Hippo signaling gene AMOT, which was inhibited by DKK1. In Experiment 3, embryos produced by fertilization with unsorted sperm were treated with DKK1 at Day 5 and abundance of transcripts for CDX2, GATA6, and NANOG determined at Days 5, 6 and 7 after insemination. There was no effect of DKK1 on expression of any of the three genes. In conclusion, female and male bovine embryos have a different pattern of gene expression as early as the morula stage, and this is due to a large extent to expression

  20. Influence of Sex on Basal and Dickkopf-1 Regulated Gene Expression in the Bovine Morula

    PubMed Central

    Denicol, Anna C.; Leão, Beatriz C. S.; Dobbs, Kyle B.; Mingoti, Gisele Z.; Hansen, Peter J.

    2015-01-01

    Sex affects function of the developing mammalian embryo as early as the preimplantation period. There were two goals of the current objective. The first was to determine the degree and nature of differences in gene expression between female and male embryos in the cow at the morula stage of development. The second objective was to determine whether DKK1, a molecule known to alter differentiation of the blastocyst, would affect gene expression differently for female and male morulae. In Experiment 1, female and male embryos were treated with DKK1 at Day 5 after insemination. Morulae were harvested 24 h after treatment, pooled in groups of 20 for microarray analysis and RNA subjected to analysis of gene expression by microarray hybridization. There were 662 differentially expressed genes between females and males and 128 of these genes had a fold change ≥ 1.5 between the two sexes. Of the genes upregulated in females, 49.5% were located in the X chromosome. Functional analysis predicted that cell survival was greater in female embryos. Experiment 2 involved a similar design except that transcripts for 12 genes previously reported to be affected by sex, DKK1 or the interaction were quantified by quantitative polymerase chain reaction. Expression of all genes tested that were affected by sex in experiment 1 was affected in a similar manner in Experiment 2. In contrast, effects of DKK1 on gene expression were largely not repeatable in Experiment 2. The exception was for the Hippo signaling gene AMOT, which was inhibited by DKK1. In Experiment 3, embryos produced by fertilization with unsorted sperm were treated with DKK1 at Day 5 and abundance of transcripts for CDX2, GATA6, and NANOG determined at Days 5, 6 and 7 after insemination. There was no effect of DKK1 on expression of any of the three genes. In conclusion, female and male bovine embryos have a different pattern of gene expression as early as the morula stage, and this is due to a large extent to expression

  1. Sex pheromone production and perception in European corn borer moths is determined by both autosomal and sex-linked genes

    PubMed Central

    Roelofs, Wendell; Glover, Thomas; Tang, Xian-Han; Sreng, Isabelle; Robbins, Paul; Eckenrode, Charles; Löfstedt, Christer; Hansson, Bill S.; Bengtsson, Bengt O.

    1987-01-01

    Inheritance patterns for sex pheromone production in females, pheromone detection on male antennal olfactory receptor cells, and male pheromone behavioral responses were studied in pheromonally distinct populations of European corn borers from New York State. Gas chromatographic analyses of pheromone glands, single sensillum recordings, and flight tunnel behavioral analyses were carried out on progeny from reciprocal crosses, as well as on progeny from subsequent F2 and maternal and paternal backcrosses. The data show that the production of the female pheromone blend primarily is controlled by a single autosomal factor, that pheromone-responding olfactory cells are controlled by another autosomal factor, and that behavioral response to pheromone is controlled by a sex-linked gene. F1 males were found to possess olfactory receptor cells that give spike amplitudes to the two pheromone isomers that are intermediate to those of the high and low amplitude cells of the parent populations. Fifty-five percent of the F1 males tested responded fully to pheromone sources ranging from the hybrid (E)-11-tetradecenyl acetate/(Z)-11-tetradecenyl acetate (E/Z) molar blend of 65:35 to the E/Z molar blend of 3:97 for the Z morph parents, but very few responded to the E/Z molar blend of 99:1 for the E morph parents. Data on the inheritance patterns support speculation that the Z morph is the ancestral and that the E morph is the derived European corn borer population. PMID:16593886

  2. Complete Dosage Compensation in Anopheles stephensi and the Evolution of Sex-Biased Genes in Mosquitoes

    PubMed Central

    Jiang, Xiaofang; Biedler, James K.; Qi, Yumin; Hall, Andrew Brantley; Tu, Zhijian

    2015-01-01

    Complete dosage compensation refers to hyperexpression of the entire X or Z chromosome in organisms with heterogametic sex chromosomes (XY male or ZW female) in order to compensate for having only one copy of the X or Z chromosome. Recent analyses suggest that complete dosage compensation, as in Drosophila melanogaster, may not be the norm. There has been no systematic study focusing on dosage compensation in mosquitoes. However, analysis of dosage compensation in Anopheles mosquitoes provides opportunities for evolutionary insights, as the X chromosome of Anopheles and that of its Dipteran relative, D. melanogaster formed independently from the same ancestral chromosome. Furthermore, Culicinae mosquitoes, including the Aedes genus, have homomorphic sex-determining chromosomes, negating the need for dosage compensation. Thus, Culicinae genes provide a rare phylogenetic context to investigate dosage compensation in Anopheles mosquitoes. Here, we performed RNA-seq analysis of male and female samples of the Asian malaria mosquito Anopheles stephensi and the yellow fever mosquito Aedes aegypti. Autosomal and X-linked genes in An. stephensi showed very similar levels of expression in both males and females, indicating complete dosage compensation. The uniformity of average expression levels of autosomal and X-linked genes remained when An. stephensi gene expression was normalized by that of their Ae. aegypti orthologs, strengthening the finding of complete dosage compensation in Anopheles. In addition, we comparatively analyzed the differentially expressed genes between adult males and adult females in both species, investigated sex-biased gene chromosomal distribution patterns in An. stephensi and provided three examples where gene duplications may have enabled the acquisition of sex-specific expression during mosquito evolution. PMID:26078263

  3. Sex Bias and Maternal Contribution to Gene Expression Divergence in Drosophila Blastoderm Embryos

    PubMed Central

    Paris, Mathilde; Villalta, Jacqueline E.; Eisen, Michael B.; Lott, Susan E.

    2015-01-01

    Early embryogenesis is a unique developmental stage where genetic control of development is handed off from mother to zygote. Yet the contribution of this transition to the evolution of gene expression is poorly understood. Here we study two aspects of gene expression specific to early embryogenesis in Drosophila: sex-biased gene expression prior to the onset of canonical X chromosomal dosage compensation, and the contribution of maternally supplied mRNAs. We sequenced mRNAs from individual unfertilized eggs and precisely staged and sexed blastoderm embryos, and compared levels between D. melanogaster, D. yakuba, D. pseudoobscura and D. virilis. First, we find that mRNA content is highly conserved for a given stage and that studies relying on pooled embryos likely systematically overstate the degree of gene expression divergence. Unlike studies done on larvae and adults where most species show a larger proportion of genes with male-biased expression, we find that transcripts in Drosophila embryos are largely female-biased in all species, likely due to incomplete dosage compensation prior to the activation of the canonical dosage compensation mechanism. The divergence of sex-biased gene expression across species is observed to be often due to lineage-specific decrease of expression; the most drastic example of which is the overall reduction of male expression from the neo-X chromosome in D. pseudoobscura, leading to a pervasive female-bias on this chromosome. We see no evidence for a faster evolution of expression on the X chromosome in embryos (no “faster-X” effect), unlike in adults, and contrary to a previous study on pooled non-sexed embryos. Finally, we find that most genes are conserved in regard to their maternal or zygotic origin of transcription, and present evidence that differences in maternal contribution to the blastoderm transcript pool may be due to species-specific divergence of transcript degradation rates. PMID:26485701

  4. Candidate genes within a 143 kb region of the flower sex locus in Vitis.

    PubMed

    Fechter, Iris; Hausmann, Ludger; Daum, Margrit; Sörensen, Thomas Rosleff; Viehöver, Prisca; Weisshaar, Bernd; Töpfer, Reinhard

    2012-03-01

    Wild Vitis species are dioecious plants, while the cultivated counterpart, Vitis vinifera subspec. vinifera, generally shows hermaphroditic flowers. In Vitis the genetic determinants of flower sex have previously been mapped to a region on chromosome 2. In a combined strategy of map-based cloning and the use of the publicly available grapevine reference genome sequence, the structure of the grapevine flower sex locus has been elucidated with the subsequent identification of candidate genes which might be involved in the development of the different flower sex types. In a fine mapping approach, the sex locus in grapevine was narrowed down using a population derived from a cross of a genotype with a Vitis vinifera background ('Schiava Grossa' × 'Riesling') with the male rootstock cv. 'Börner' (V. riparia × V. cinerea). A physical map of 143 kb was established from BAC clones spanning the 0.5 cM region defined by the closest flanking recombination break points. Sequencing and gene annotation of the entire region revealed several candidate genes with a potential impact on flower sex formation. One of the presumed candidate genes, an adenine phosphoribosyltransferase, was analysed in more detail. The results led to the development of a marker for the presence or absence of the female alleles, while the male and hermaphroditic alleles are still to be differentiated. The impact of other candidate genes is discussed, especially with regard to plant hormone actions. The markers developed will permit the selection of female breeding lines which do not require laborious emasculation thus considerably simplifying grapevine breeding. The genetic finger prints displayed that our cultivated grapevines frequently carry a female allele while homozygous hermaphrodites are rare.

  5. Drosophila switch gene Sex-lethal can bypass its switch-gene target transformer to regulate aspects of female behavior.

    PubMed

    Evans, Daniel S; Cline, Thomas W

    2013-11-19

    The switch gene Sex-lethal (Sxl) was thought to elicit all aspects of Drosophila female somatic differentiation other than size dimorphism by controlling only the switch gene transformer (tra). Here we show instead that Sxl controls an aspect of female sexual behavior by acting on a target other than or in addition to tra. We inferred the existence of this unknown Sxl target from the observation that a constitutively feminizing tra transgene that restores fertility to tra(-) females failed to restore fertility to Sxl-mutant females that were adult viable but functionally tra(-). The sterility of these mutant females was caused by an ovulation failure. Because tra expression is not sufficient to render these Sxl-mutant females fertile, we refer to this pathway as the tra-insufficient feminization (TIF) branch of the sex-determination regulatory pathway. Using a transgene that conditionally expresses two Sxl feminizing isoforms, we find that the TIF branch is required developmentally for neurons that also sex-specifically express fruitless, a tra gene target controlling sexual behavior. Thus, in a subset of fruitless neurons, targets of the TIF and tra pathways appear to collaborate to control ovulation. In most insects, Sxl has no sex-specific functions, and tra, rather than Sxl, is both the target of the primary sex signal and the gene that maintains the female developmental commitment via positive autoregulation. The TIF pathway may represent an ancestral female-specific function acquired by Sxl in an early evolutionary step toward its becoming the regulator of tra in Drosophila.

  6. Drosophila switch gene Sex-lethal can bypass its switch-gene target transformer to regulate aspects of female behavior

    PubMed Central

    Evans, Daniel S.; Cline, Thomas W.

    2013-01-01

    The switch gene Sex-lethal (Sxl) was thought to elicit all aspects of Drosophila female somatic differentiation other than size dimorphism by controlling only the switch gene transformer (tra). Here we show instead that Sxl controls an aspect of female sexual behavior by acting on a target other than or in addition to tra. We inferred the existence of this unknown Sxl target from the observation that a constitutively feminizing tra transgene that restores fertility to tra− females failed to restore fertility to Sxl-mutant females that were adult viable but functionally tra−. The sterility of these mutant females was caused by an ovulation failure. Because tra expression is not sufficient to render these Sxl-mutant females fertile, we refer to this pathway as the tra-insufficient feminization (TIF) branch of the sex-determination regulatory pathway. Using a transgene that conditionally expresses two Sxl feminizing isoforms, we find that the TIF branch is required developmentally for neurons that also sex-specifically express fruitless, a tra gene target controlling sexual behavior. Thus, in a subset of fruitless neurons, targets of the TIF and tra pathways appear to collaborate to control ovulation. In most insects, Sxl has no sex-specific functions, and tra, rather than Sxl, is both the target of the primary sex signal and the gene that maintains the female developmental commitment via positive autoregulation. The TIF pathway may represent an ancestral female-specific function acquired by Sxl in an early evolutionary step toward its becoming the regulator of tra in Drosophila. PMID:24191002

  7. Identification and functional analyses of sex determination genes in the sexually dimorphic stag beetle Cyclommatus metallifer.

    PubMed

    Gotoh, Hiroki; Zinna, Robert A; Warren, Ian; DeNieu, Michael; Niimi, Teruyuki; Dworkin, Ian; Emlen, Douglas J; Miura, Toru; Lavine, Laura C

    2016-03-22

    Genes in the sex determination pathway are important regulators of sexually dimorphic animal traits, including the elaborate and exaggerated male ornaments and weapons of sexual selection. In this study, we identified and functionally analyzed members of the sex determination gene family in the golden metallic stag beetle Cyclommatus metallifer, which exhibits extreme differences in mandible size between males and females. We constructed a C. metallifer transcriptomic database from larval and prepupal developmental stages and tissues of both males and females. Using Roche 454 pyrosequencing, we generated a de novo assembled database from a total of 1,223,516 raw reads, which resulted in 14,565 isotigs (putative transcript isoforms) contained in 10,794 isogroups (putative identified genes). We queried this database for C. metallifer conserved sex determination genes and identified 14 candidate sex determination pathway genes. We then characterized the roles of several of these genes in development of extreme sexual dimorphic traits in this species. We performed molecular expression analyses with RT-PCR and functional analyses using RNAi on three C. metallifer candidate genes--Sex-lethal (CmSxl), transformer-2 (Cmtra2), and intersex (Cmix). No differences in expression pattern were found between the sexes for any of these three genes. In the RNAi gene-knockdown experiments, we found that only the Cmix had any effect on sexually dimorphic morphology, and these mimicked the effects of Cmdsx knockdown in females. Knockdown of CmSxl had no measurable effects on stag beetle phenotype, while knockdown of Cmtra2 resulted in complete lethality at the prepupal period. These results indicate that the roles of CmSxl and Cmtra2 in the sex determination cascade are likely to have diverged in stag beetles when compared to Drosophila. Our results also suggest that Cmix has a conserved role in this pathway. In addition to those three genes, we also performed a more complete

  8. The candidate sex-reversing DAX1 gene is autosomal in marsupials: implications for the evolution of sex determination in mammals.

    PubMed

    Pask, A; Toder, R; Wilcox, S A; Camerino, G; Graves, J A

    1997-05-01

    The human X-linked DAX1 gene was cloned from the region of the short arm of the human X found in duplicate in sex-reversed Xdup Y females (E. Zanaria et al., 1994, Nature 372: 635-641). DAX1 is suggested to be required for ovarian differentiation and to play an important role in mammalian sex determination or differentiation pathways. Its proposed dose-dependent effect on sexual development suggests that DAX1 could represent an evolutionary link with an ancestral sex-determining mechanism that depended on the dosage of an X-linked gene. Furthermore, DAX1 could also represent the putative X-linked switch gene, which independently controls sexual dimorphisms in marsupial mammals in an X-dose-dependent manner (D.W. Cooper et al., 1993, Semin. Dev. 4: 117-128). If DAX1 has a present role in marsupial sexual differentiation or had an ancestral role in mammalian sex determination, it would be expected to lie on the marsupial X chromosome, despite the autosomal localization of other human Xp genes. We therefore cloned and mapped the DAX1 gene in the tammar wallaby (Macropus eugenii). DAX1 was located on wallaby chromosome 5p near other human Xp genes, indicating that it was originally autosomal and that it is not involved in X-linked dose-dependent sex determination in an ancestral mammal nor in marsupial sexual differentiation.

  9. The candidate sex-reversing DAX1 gene is autosomal in marsupials: Implications for the evolution of sex determination in mammals

    SciTech Connect

    Pask, A.; Toder, R.; Wilcox, S.A.

    1997-05-01

    The human X-linked DAX1 gene was cloned from the region of the short arm of the human X found in duplicate in sex-reversed X{sub dup}Y females. DAX1 is suggested to be required for ovarian differentiation and to play an important role in mammalian sex determination or differentiation pathways. Its proposed dose-dependent effect on sexual development suggests that DAX1 could represent an evolutionary link with an ancestral sex-determining mechanism that depended on the dosage of an X-linked gene. Furthermore, DAX1 could also represent the putative X-linked switch gene, which independently controls sexual dimorphisms in marsupial mammals in an X-dose-dependent manner. If DAX1 has a present role in marsupial sexual differentiation or had an ancestral role in mammalian sex determination, it would be expected to lie on the marsupial X chromosome, despite the autosomal localization of other human Xp genes. We therefore cloned and mapped the DAX1 gene in the tammar wallaby (Macropus eugenii). DAX1 was located on wallaby chromosome 5p near other human Xp genes, indicating that it was originally autosomal and that it is not involved in X-linked dose-dependent sex determination in an ancestral mammal nor in marsupial sexual differentiation. 28 refs., 4 figs.

  10. Differential Gene Expression across Breed and Sex in Commercial Pigs Administered Fenbendazole and Flunixin Meglumine

    PubMed Central

    Howard, Jeremy T.; O’Nan, Audrey T.; Maltecca, Christian; Baynes, Ronald E.; Ashwell, Melissa S.

    2015-01-01

    Characterizing the variability in transcript levels across breeds and sex in swine for genes that play a role in drug metabolism may shed light on breed and sex differences in drug metabolism. The objective of the study is to determine if there is heterogeneity between swine breeds and sex in transcript levels for genes previously shown to play a role in drug metabolism for animals administered flunixin meglumine or fenbendazole. Crossbred nursery female and castrated male pigs (n = 169) spread across 5 groups were utilized. Sires (n = 15) of the pigs were purebred Duroc, Landrace, Yorkshire or Hampshire boars mated to a common sow population. Animals were randomly placed into the following treatments: no drug (control), flunixin meglumine, or fenbendazole. One hour after the second dosing, animals were sacrificed and liver samples collected. Quantitative Real-Time PCR was used to measure liver gene expression of the following genes: SULT1A1, ABCB1, CYP1A2, CYP2E1, CYP3A22 and CYP3A29. The control animals were used to investigate baseline transcript level differences across breed and sex. Post drug administration transcript differences across breed and sex were investigated by comparing animals administered the drug to the controls. Contrasts to determine fold change were constructed from a model that included fixed and random effects within each drug. Significant (P-value <0.007) basal transcript differences were found across breeds for SULT1A1, CYP3A29 and CYP3A22. Across drugs, significant (P-value <0.0038) transcript differences existed between animals given a drug and controls across breeds and sex for ABCB1, PS and CYP1A2. Significant (P <0.0038) transcript differences across breeds were found for CYP2E1 and SULT1A1 for flunixin meglumine and fenbendazole, respectively. The current analysis found transcript level differences across swine breeds and sex for multiple genes, which provides greater insight into the relationship between flunixin meglumine and

  11. Differential Gene Expression across Breed and Sex in Commercial Pigs Administered Fenbendazole and Flunixin Meglumine.

    PubMed

    Howard, Jeremy T; O'Nan, Audrey T; Maltecca, Christian; Baynes, Ronald E; Ashwell, Melissa S

    2015-01-01

    Characterizing the variability in transcript levels across breeds and sex in swine for genes that play a role in drug metabolism may shed light on breed and sex differences in drug metabolism. The objective of the study is to determine if there is heterogeneity between swine breeds and sex in transcript levels for genes previously shown to play a role in drug metabolism for animals administered flunixin meglumine or fenbendazole. Crossbred nursery female and castrated male pigs (n = 169) spread across 5 groups were utilized. Sires (n = 15) of the pigs were purebred Duroc, Landrace, Yorkshire or Hampshire boars mated to a common sow population. Animals were randomly placed into the following treatments: no drug (control), flunixin meglumine, or fenbendazole. One hour after the second dosing, animals were sacrificed and liver samples collected. Quantitative Real-Time PCR was used to measure liver gene expression of the following genes: SULT1A1, ABCB1, CYP1A2, CYP2E1, CYP3A22 and CYP3A29. The control animals were used to investigate baseline transcript level differences across breed and sex. Post drug administration transcript differences across breed and sex were investigated by comparing animals administered the drug to the controls. Contrasts to determine fold change were constructed from a model that included fixed and random effects within each drug. Significant (P-value <0.007) basal transcript differences were found across breeds for SULT1A1, CYP3A29 and CYP3A22. Across drugs, significant (P-value <0.0038) transcript differences existed between animals given a drug and controls across breeds and sex for ABCB1, PS and CYP1A2. Significant (P <0.0038) transcript differences across breeds were found for CYP2E1 and SULT1A1 for flunixin meglumine and fenbendazole, respectively. The current analysis found transcript level differences across swine breeds and sex for multiple genes, which provides greater insight into the relationship between flunixin meglumine and

  12. Genome-Wide Analysis of Chromatin States Reveals Distinct Mechanisms of Sex-Dependent Gene Regulation in Male and Female Mouse Liver

    PubMed Central

    Sugathan, Aarathi

    2013-01-01

    Chromatin state maps were developed to elucidate sex differences in chromatin structure and their impact on sex-differential chromatin accessibility and sex-biased gene expression in mouse liver. Genes in active, inactive, and poised chromatin states exhibited differential responsiveness to ligand-activated nuclear receptors and distinct enrichments for functional gene categories. Sex-biased genes were clustered by chromatin environments and mapped to DNase-hypersensitive sites (DHS) classified by sex bias in chromatin accessibility and enhancer modifications. Results were integrated with genome-wide binding data for five transcription factors implicated in growth hormone-regulated, sex-biased liver gene expression, leading to the following findings. (i) Sex-biased DHS, but not sex-biased genes, are frequently characterized by sex-differential chromatin states, indicating distal regulation. (ii) Trimethylation of histone H3 at K27 (H3K27me3) is a major sex-biased repressive mark at highly female-biased but not at highly male-biased genes. (iii) FOXA factors are associated with sex-dependent chromatin opening at male-biased but not female-biased regulatory sites. (iv) Sex-biased STAT5 binding is enriched at sex-biased DHS marked as active enhancers and preferentially targets sex-biased genes with sex-differences in local chromatin marks. (v) The male-biased repressor BCL6 preferentially targets female-biased genes and regulatory sites in a sex-independent chromatin state. (vi) CUX2, a female-specific repressor of male-biased genes, also activates strongly female-biased genes, in association with loss of H3K27me3 marks. Chromatin states are thus a major determinant of sex-biased chromatin accessibility and gene expression, with FOXA pioneer factors proposed to confer sex-dependent chromatin opening and STAT5, but not BCL6, regulating sex-biased genes by binding to sites in a sex-biased chromatin state. PMID:23836885

  13. Age and sex dependent changes in liver gene expression during the life cycle of the rat

    PubMed Central

    2010-01-01

    Background Age- and sex-related susceptibility to adverse drug reactions and disease is a key concern in understanding drug safety and disease progression. We hypothesize that the underlying suite of hepatic genes expressed at various life cycle stages will impact susceptibility to adverse drug reactions. Understanding the basal liver gene expression patterns is a necessary first step in addressing this hypothesis and will inform our assessments of adverse drug reactions as the liver plays a central role in drug metabolism and biotransformation. Untreated male and female F344 rats were sacrificed at 2, 5, 6, 8, 15, 21, 52, 78, and 104 weeks of age. Liver tissues were collected for histology and gene expression analysis. Whole-genome rat microarrays were used to query global expression profiles. Results An initial list of differentially expressed genes was selected using criteria based upon p-value (p < 0.05) and fold-change (+/- 1.5). Three dimensional principal component analyses revealed differences between males and females beginning at 2 weeks with more divergent profiles beginning at 5 weeks. The greatest sex-differences were observed between 8 and 52 weeks before converging again at 104 weeks. K-means clustering identified groups of genes that displayed age-related patterns of expression. Various adult aging-related clusters represented gene pathways related to xenobiotic metabolism, DNA damage repair, and oxidative stress. Conclusions These results suggest an underlying role for genes in specific clusters in potentiating age- and sex-related differences in susceptibility to adverse health effects. Furthermore, such a comprehensive picture of life cycle changes in gene expression deepens our understanding and informs the utility of liver gene expression biomarkers. PMID:21118493

  14. Sex-biased gene flow among elk in the greater Yellowstone ecosystem

    USGS Publications Warehouse

    Hand, Brian K.; Chen, Shanyuan; Anderson, Neil; Beja-Pereira, Albano; Cross, Paul C.; Ebinger, Michael R.; Edwards, Hank; Garrott, Robert A.; Kardos, Marty D.; Kauffman, Matthew J.; Landguth, Erin L.; Middleton, Arthur; Scurlock, Brandon M.; White, P.J.; Zager, Pete; Schwartz, Michael K.; Luikart, Gordon

    2014-01-01

    We quantified patterns of population genetic structure to help understand gene flow among elk populations across the Greater Yellowstone Ecosystem. We sequenced 596 base pairs of the mitochondrial control region of 380 elk from eight populations. Analysis revealed high mitochondrial DNA variation within populations, averaging 13.0 haplotypes with high mean gene diversity (0.85). The genetic differentiation among populations for mitochondrial DNA was relatively high (FST  =  0.161; P  =  0.001) compared to genetic differentiation for nuclear microsatellite data (FST  =  0.002; P  =  0.332), which suggested relatively low female gene flow among populations. The estimated ratio of male to female gene flow (mm/mf  =  46) was among the highest we have seen reported for large mammals. Genetic distance (for mitochondrial DNA pairwise FST) was not significantly correlated with geographic (Euclidean) distance between populations (Mantel's r  =  0.274, P  =  0.168). Large mitochondrial DNA genetic distances (e.g., FST > 0.2) between some of the geographically closest populations (<65 km) suggested behavioral factors and/or landscape features might shape female gene flow patterns. Given the strong sex-biased gene flow, future research and conservation efforts should consider the sexes separately when modeling corridors of gene flow or predicting spread of maternally transmitted diseases. The growing availability of genetic data to compare male vs. female gene flow provides many exciting opportunities to explore the magnitude, causes, and implications of sex-biased gene flow likely to occur in many species.

  15. Gene by Sex Interaction for Measures of Obesity in the Framingham Heart Study

    PubMed Central

    Benjamin, Ashlee M.; Suchindran, Sunil; Pearce, Kaela; Rowell, Jennifer; Lien, Lillian F.; Guyton, John R.; McCarthy, Jeanette J.

    2011-01-01

    Obesity is an increasingly prevalent and severe health concern with a substantial heritable component and marked sex differences. We sought to determine if the effect of genetic variants also differed by sex by performing a genome-wide association study modeling the effect of genotype-by-sex interaction on obesity phenotypes. Genotype data from individuals in the Framingham Heart Study Offspring cohort were analyzed across five exams. Although no variants showed genome-wide significant gene-by-sex interaction in any individual exam, four polymorphisms displayed a consistent BMI association (P-values .00186 to .00010) across all five exams. These variants were clustered downstream of LYPLAL1, which encodes a lipase/esterase expressed in adipose tissue, a locus previously identified as having sex-specific effects on central obesity. Primary effects in males were in the opposite direction from females and were replicated in Framingham Generation 3. Our data support a sex-influenced association between genetic variation at the LYPLAL1 locus and obesity-related traits. PMID:21253498

  16. Sequencing the mouse Y chromosome reveals convergent gene acquisition and amplification on both sex chromosomes

    PubMed Central

    Soh, Y.Q. Shirleen; Alföldi, Jessica; Pyntikova, Tatyana; Brown, Laura G.; Graves, Tina; Minx, Patrick J.; Fulton, Robert S.; Kremitzki, Colin; Koutseva, Natalia; Mueller, Jacob L.; Rozen, Steve; Hughes, Jennifer F.; Owens, Elaine; Womack, James E.; Murphy, William J.; Cao, Qing; de Jong, Pieter; Warren, Wesley C.; Wilson, Richard K.; Skaletsky, Helen; Page, David C.

    2014-01-01

    Summary We sequenced the MSY (Male-Specific region of the Y chromosome) of the C57BL/6J strain of the laboratory mouse Mus musculus. In contrast to theories that Y chromosomes are heterochromatic and gene poor, the mouse MSY is 99.9% euchromatic and contains about 700 protein-coding genes. Only two percent of the MSY derives from the ancestral autosomes that gave rise to the mammalian sex chromosomes. Instead, all but 50 of the MSY's genes belong to three acquired, massively amplified gene families that have no homologs on primate MSYs, but do have acquired, amplified homologs on the mouse X chromosome. The complete mouse MSY sequence brings to light dramatic forces in sex chromosome evolution: lineage-specific convergent acquisition and amplification of X-Y gene families, possibly fueled by antagonism between acquired X-Y homologs. The mouse MSY sequence presents opportunities for experimental studies of a sex-specific chromosome in its entirety, in a genetically tractable model organism. PMID:25417157

  17. Sequencing the mouse Y chromosome reveals convergent gene acquisition and amplification on both sex chromosomes.

    PubMed

    Soh, Y Q Shirleen; Alföldi, Jessica; Pyntikova, Tatyana; Brown, Laura G; Graves, Tina; Minx, Patrick J; Fulton, Robert S; Kremitzki, Colin; Koutseva, Natalia; Mueller, Jacob L; Rozen, Steve; Hughes, Jennifer F; Owens, Elaine; Womack, James E; Murphy, William J; Cao, Qing; de Jong, Pieter; Warren, Wesley C; Wilson, Richard K; Skaletsky, Helen; Page, David C

    2014-11-06

    We sequenced the MSY (male-specific region of the Y chromosome) of the C57BL/6J strain of the laboratory mouse Mus musculus. In contrast to theories that Y chromosomes are heterochromatic and gene poor, the mouse MSY is 99.9% euchromatic and contains about 700 protein-coding genes. Only 2% of the MSY derives from the ancestral autosomes that gave rise to the mammalian sex chromosomes. Instead, all but 45 of the MSY's genes belong to three acquired, massively amplified gene families that have no homologs on primate MSYs but do have acquired, amplified homologs on the mouse X chromosome. The complete mouse MSY sequence brings to light dramatic forces in sex chromosome evolution: lineage-specific convergent acquisition and amplification of X-Y gene families, possibly fueled by antagonism between acquired X-Y homologs. The mouse MSY sequence presents opportunities for experimental studies of a sex-specific chromosome in its entirety, in a genetically tractable model organism.

  18. Phylogenetic distribution and evolutionary dynamics of the sex determination genes doublesex and transformer in insects.

    PubMed

    Geuverink, E; Beukeboom, L W

    2014-01-01

    Sex determination in insects is characterized by a gene cascade that is conserved at the bottom but contains diverse primary signals at the top. The bottom master switch gene doublesex is found in all insects. Its upstream regulator transformer is present in the orders Hymenoptera, Coleoptera and Diptera, but has thus far not been found in Lepidoptera and in the basal lineages of Diptera. transformer is presumed to be ancestral to the holometabolous insects based on its shared domains and conserved features of autoregulation and sex-specific splicing. We interpret that its absence in basal lineages of Diptera and its order-specific conserved domains indicate multiple independent losses or recruitments into the sex determination cascade. Duplications of transformer are found in derived families within the Hymenoptera, characterized by their complementary sex determination mechanism. As duplications are not found in any other insect order, they appear linked to the haplodiploid reproduction of the Hymenoptera. Further phylogenetic analyses combined with functional studies are needed to understand the evolutionary history of the transformer gene among insects. © 2013 S. Karger AG, Basel.

  19. Sex identification of pigs using polymerase chain reaction amplification of the amelogenin gene.

    PubMed

    Sembon, Shoichiro; Suzuki, Shun-ichi; Fuchimoto, Dai-ichiro; Iwamoto, Masaki; Kawarasaki, Tatsuo; Onishi, Akira

    2008-11-01

    The amelogenin (AMEL) gene exists on both sex chromosomes of various mammalian species and the length and sequence of the noncoding regions differ between the two chromosome-specific alleles. Because both forms can be amplified using a single primer set, the use of AMEL in polymerase chain reaction (PCR)-based methods has facilitated sex identification in various mammalian species, including cattle, sheep and humans. In this study, we designed PCR primers to yield different-sized products from the AMEL genes on the X (AMELX) and Y (AMELY) chromosomes of pigs. PCR amplification of genomic DNA samples collected from various breeds of pigs (European breeds: Landrace, Large White, Duroc and Berkshire; Chinese breeds: Meishan and Jinhua and their crossbreeds) yielded the expected products. For all breeds, DNA from male pigs produced two bands (520 and 350 bp; AMELX and AMELY, respectively), whereas samples from female pigs generated only the 520 bp product. We then tested the use of PCR of AMEL for sex identification of in vitro-produced (IVP) porcine embryos sampled at 2 or 5 to 6 days after fertilization; germinal vesicle (GV)-stage oocytes and electroactivated embryos were used as controls. More than 88% of the GV-stage oocytes and electroactivated embryos yielded a single 520 bp single band and about 50% of the IVP embryos tested produced both bands. Our findings show that PCR analysis of the AMEL gene is reliable for sex identification of pigs and porcine embryos.

  20. Sex identification of Japanese black bear, Ursus thibetanus japonicus, by PCR based on amelogenin gene.

    PubMed

    Yamamoto, Kaori; Tsubota, Toshio; Komatsu, Takeshi; Katayama, Atsushi; Murase, Tetsuma; Kita, Isao; Kudo, Tadaaki

    2002-06-01

    A method for sex identification of the Japanese black bear was examined using a polymerase chain reaction (PCR) and sequencing of a part of the amelogenin gene. This gene is located on the X and Y chromosomes, and there are 54 nucleotide deletions on the Y chromosome-specific gene. Forty-seven (26 male and 21 female) DNA samples and 23 (13 male and 10 female) DNA samples, respectively extracted from white blood cells and hairs of Japanese black bears were analyzed. The primers SE47 and SE48 from this X-Y homologous region were used in sex identification by PCR amplification. These primers amplified X- and Y-specific bands, which could be used to discriminate between sexes by a length polymorphism in all samples. We suggest that PCR amplification using the primers SE47 and SE48 is useful for sex determination of the Japanese black bear and could be applied to DNA analysis of small samples such as hairs.

  1. Polymorphisms in steroidogenesis genes, sex steroid levels, and high myopia in the Taiwanese population

    PubMed Central

    Chen, Zoe Tzu-Yi; Liao, Ya-Tang; Shih, Yung-Feng; Lin, Luke Long-Kuang

    2011-01-01

    Purpose To evaluate the relationship among single nucleotide polymorphisms (SNPs) in steroidogenesis enzyme genes, serum levels of sex steroids, and high myopia in Taiwanese male and female populations. Methods A campus-based sample of 283 cases (145 males and 138 females) with high myopia and 280 controls (144 males and 136 females) with low myopia or emmetropia was studied. Estradiol, progesterone, and testosterone levels were determined using enzyme-linked immunosorbent assay kits. We genotyped six SNPs within five steroidogenesis enzyme genes (17 alpha-hydroxylase/17,20 lyase [CYP17A1], 3 beta-hydroxysteroid dehydrogenase [HSD3B1], 17 beta-hydroxysteroid dehydrogenase 1 [HSD17B1], steroid-5-alpha-reductase, alpha polypeptide 2 [SRD5A2], and aromatase [CYP19A1]) using polymerase chain reaction–restriction fragment length polymorphism methods. Student’s t-tests, χ2 tests, logistic regression, multifactor dimensionality reduction (MDR) methods, and ANOVA were used to determine significance. Results An MDR analysis corroborated the synergistic genotype association and demonstrated that synergistic interaction between rs6203 (HSD3B1), rs10046 (CYP19A1), and sex might confer susceptibility to high myopia (p=0.019). In both male and female subjects, levels of testosterone were significantly higher in cases than in controls; in male subjects, the levels of estradiol were significantly higher and those of progesterone were significantly lower in cases (all p-values <0.001). The rs605059 (HSD17B1), with sex-gene interaction, showed association with estradiol levels in males (p=0.035) and testosterone levels in females (p=0.027). Conclusions Testosterone levels correlate with high myopia, and interaction of steroidogenesis enzyme genes and sex may be a modulating factor in sex hormone metabolism and high-myopia risk. PMID:21921981

  2. Evidence for emergence of sex-determining gene(s) in a centromeric region in Vasconcellea parviflora.

    PubMed

    Iovene, Marina; Yu, Qingyi; Ming, Ray; Jiang, Jiming

    2015-02-01

    Sex chromosomes have been studied in many plant and animal species. However, few species are suitable as models to study the evolutionary histories of sex chromosomes. We previously demonstrated that papaya (Carica papaya) (2n = 2x = 18), a fruit tree in the family Caricaceae, contains recently emerged but cytologically heteromorphic X/Y chromosomes. We have been intrigued by the possible presence and evolution of sex chromosomes in other dioecious Caricaceae species. We selected a set of 22 bacterial artificial chromosome (BAC) clones that are distributed along the papaya X/Y chromosomes. These BACs were mapped to the meiotic pachytene chromosomes of Vasconcellea parviflora (2n = 2x = 18), a species that diverged from papaya ∼27 million years ago. We demonstrate that V. parviflora contains a pair of heteromorphic X/Y chromosomes that are homologous to the papaya X/Y chromosomes. The comparative mapping results revealed that the male-specific regions of the Y chromosomes (MSYs) probably initiated near the centromere of the Y chromosomes in both species. The two MSYs, however, shared only a small chromosomal domain near the centromere in otherwise rearranged chromosomes. The V. parviflora MSY expanded toward the short arm of the chromosome, whereas the papaya MSY expanded in the opposite direction. Most BACs mapped to papaya MSY were not located in V. parviflora MSY, revealing different DNA compositions in the two MSYs. These results suggest that mutation of gene(s) in the centromeric region may have triggered sex chromosome evolution in these plant species.

  3. Sequences homologous to ZFY, a candidate human sex-determining gene, are autosomal in marsupials.

    PubMed

    Sinclair, A H; Foster, J W; Spencer, J A; Page, D C; Palmer, M; Goodfellow, P N; Graves, J A

    Sexual differentiation in placental mammals results from the action of a testis-determining gene encoded by the Y chromosome. This gene causes the indifferent gonad to develop as a testis, thereby initiating a hormonal cascade which produces a male phenotype. Recently, a candidate for the testis-determining gene (ZFY, Y-borne zinc-finger protein) has been cloned. The ZFY probe detects a male-specific (Y-linked) sequence in DNA from a range of eutherian mammals, as well as an X-linked sequence (ZFX) which maps to the human X chromosome. In marsupials it is also the Y chromosome that seems to determine the fate of the gonad, but not all sexual dimorphisms. Using the ZFY probe we find, surprisingly, that the ZFY homologous sequences are not on either the X or the Y chromosome in marsupials, but map to the autosomes. This implies ZFY is not the primary sex-determining gene in marsupials. Either the genetic pathways of sex determination in marsupials and eutherians differ, or they are identical and ZFY is not the primary signal in human sex determination.

  4. Discovery and identification of candidate sex-related genes based on transcriptome sequencing of Russian sturgeon (Acipenser gueldenstaedtii) gonads.

    PubMed

    Chen, Yadong; Xia, Yongtao; Shao, Changwei; Han, Lei; Chen, Xuejie; Yu, Mengjun; Sha, Zhenxia

    2016-07-01

    As the Russian sturgeon (Acipenser gueldenstaedtii) is an important food and is the main source of caviar, it is necessary to discover the genes associated with its sex differentiation. However, the complicated life and maturity cycles of the Russian sturgeon restrict the accurate identification of sex in early development. To generate a first look at specific sex-related genes, we sequenced the transcriptome of gonads in different development stages (1, 2, and 5 yr old stages) with next-generation RNA sequencing. We generated >60 million raw reads, and the filtered reads were assembled into 263,341 contigs, which produced 38,505 unigenes. Genes involved in signal transduction mechanisms were the most abundant, suggesting that development of sturgeon gonads is under control of signal transduction mechanisms. Differentially expressed gene analysis suggests that more genes for protein synthesis, cytochrome c oxidase subunits, and ribosomal proteins were expressed in female gonads than in male. Meanwhile, male gonads expressed more transposable element transposase, reverse transcriptase, and transposase-related genes than female. In total, 342, 782, and 7,845 genes were detected in intersex, male, and female transcriptomes, respectively. The female gonad expressed more genes than the male gonad, and more genes were involved in female gonadal development. Genes (sox9, foxl2) are differentially expressed in different sexes and may be important sex-related genes in Russian sturgeon. Sox9 genes are responsible for the development of male gonads and foxl2 for female gonads. Copyright © 2016 the American Physiological Society.

  5. Deregulated Sex Chromosome Gene Expression with Male Germ Cell-Specific Loss of Dicer1

    PubMed Central

    Snyder, Elizabeth; Buaas, F. William; Gu, Tongjun; Stearns, Timothy M.; Sharma, Manju; Murchison, Elizabeth P.; Puente, Gabriella C.; Braun, Robert E.

    2012-01-01

    MicroRNAs (miRNAs) are a class of endogenous, non-coding RNAs that mediate post-transcriptional gene silencing by inhibiting mRNA translation and promoting mRNA decay. DICER1, an RNase III endonuclease encoded by Dicer1, is required for processing short 21–22 nucleotide miRNAs from longer double-stranded RNA precursors. Here, we investigate the loss of Dicer1 in mouse postnatal male germ cells to determine how disruptions in the miRNA biogenesis pathway may contribute to infertility. Reduced levels of Dicer1 transcripts and DICER1 were confirmed in germ cell knock-out (GCKO) testes by postnatal day 18 (P18). Compared to wild-type (WT) at 8 weeks, GCKO males had no change in body weight; yet showed significant reductions in testis mass and sperm number. Histology and fertility tests confirmed spermatogenic failure in GCKO males. Array analyses at P18 showed that in comparison to WT testes, 75% of miRNA genes and 37% of protein coding genes were differentially expressed in GCKO testes. Among these, 96% of miRNA genes were significantly down-regulated, while 4% miRNA genes were overexpressed. Interestingly, we observed preferential overexpression of genes encoded on the sex chromosomes in GCKO testes, including more than 80% of previously identified targets of meiotic sex chromosome inactivation (MSCI). Compared to WT, GCKO mice showed higher percentages of germ cells at early meiotic stages (leptotene and zygotene) but lower percentages at later stages (pachytene, diplotene and metaphase I) providing evidence that deletion of Dicer1 leads to disruptions in meiotic progression. Therefore, deleting Dicer1 in early postnatal germ cells resulted in deregulation of transcripts encoded by genes on the sex chromosomes, impaired meiotic progression and led to spermatogenic failure and infertility. PMID:23056286

  6. Deregulated sex chromosome gene expression with male germ cell-specific loss of Dicer1.

    PubMed

    Greenlee, Anne R; Shiao, Meng-Shin; Snyder, Elizabeth; Buaas, F William; Gu, Tongjun; Stearns, Timothy M; Sharma, Manju; Murchison, Elizabeth P; Puente, Gabriella C; Braun, Robert E

    2012-01-01

    MicroRNAs (miRNAs) are a class of endogenous, non-coding RNAs that mediate post-transcriptional gene silencing by inhibiting mRNA translation and promoting mRNA decay. DICER1, an RNase III endonuclease encoded by Dicer1, is required for processing short 21-22 nucleotide miRNAs from longer double-stranded RNA precursors. Here, we investigate the loss of Dicer1 in mouse postnatal male germ cells to determine how disruptions in the miRNA biogenesis pathway may contribute to infertility. Reduced levels of Dicer1 transcripts and DICER1 were confirmed in germ cell knock-out (GCKO) testes by postnatal day 18 (P18). Compared to wild-type (WT) at 8 weeks, GCKO males had no change in body weight; yet showed significant reductions in testis mass and sperm number. Histology and fertility tests confirmed spermatogenic failure in GCKO males. Array analyses at P18 showed that in comparison to WT testes, 75% of miRNA genes and 37% of protein coding genes were differentially expressed in GCKO testes. Among these, 96% of miRNA genes were significantly down-regulated, while 4% miRNA genes were overexpressed. Interestingly, we observed preferential overexpression of genes encoded on the sex chromosomes in GCKO testes, including more than 80% of previously identified targets of meiotic sex chromosome inactivation (MSCI). Compared to WT, GCKO mice showed higher percentages of germ cells at early meiotic stages (leptotene and zygotene) but lower percentages at later stages (pachytene, diplotene and metaphase I) providing evidence that deletion of Dicer1 leads to disruptions in meiotic progression. Therefore, deleting Dicer1 in early postnatal germ cells resulted in deregulation of transcripts encoded by genes on the sex chromosomes, impaired meiotic progression and led to spermatogenic failure and infertility.

  7. Comparison of the power of haplotype-based versus single- and multilocus association methods for gene × environment (gene × sex) interactions and application to gene × smoking and gene × sex interactions in rheumatoid arthritis

    PubMed Central

    Dempfle, Astrid; Hein, Rebecca; Beckmann, Lars; Scherag, André; Nguyen, Thuy Trang; Schäfer, Helmut; Chang-Claude, Jenny

    2007-01-01

    Accounting for interactions with environmental factors in association studies may improve the power to detect genetic effects and may help identifying important environmental effect modifiers. The power of unphased genotype-versus haplotype-based methods in regions with high linkage disequilibrium (LD), as measured by D', for analyzing gene × environment (gene × sex) interactions was compared using the Genetic Analysis Workshop 15 (GAW15) simulated data on rheumatoid arthritis with prior knowledge of the answers. Stepwise and regular conditional logistic regression (CLR) was performed using a matched case-control sample for a HLA region interacting with sex. Haplotype-based analyses were performed using a haplotype-sharing-based Mantel statistic and a test for haplotype-trait association in a general linear model framework. A step-down minP algorithm was applied to derive adjusted p-values and to allow for power comparisons. These methods were also applied to the GAW15 real data set for PTPN22. For markers in strong LD, stepwise CLR performed poorly because of the correlation/collinearity between the predictors in the model. The power was high for detecting genetic main effects using simple CLR models and haplotype-based methods and for detecting joint effects using CLR and Mantel statistics. Only the haplotype-trait association test had high power to detect the gene × sex interaction. In the PTPN22 region with markers characterized by strong LD, all methods indicated a significant genotype × sex interaction in a sample of about 1000 subjects. The previously reported R620W single-nucleotide polymorphism was identified using logistic regression, but the haplotype-based methods did not provide any precise location information. PMID:18466575

  8. Osteoblast differentiation profiles define sex specific gene expression patterns in craniosynostosis

    PubMed Central

    Park, Sarah S.; Beyer, Richard P.; Smyth, Matthew D.; Clarke, Christine M.; Timms, Andrew E.; Bammler, Theo K.; Stamper, Brendan D.; Mecham, Brigham H.; Gustafson, Jennifer A.; Cunningham, Michael L.

    2015-01-01

    Single suture craniosynostosis (SSC) is the premature fusion of one calvarial suture and occurs in 1-1,700-2,500 live births. Congenital fusion of either the sagittal, metopic, or coronal sutures represents 95% of all cases of SSC. Sagittal and metopic synostosis have a male preponderance (3:1) while premature fusion of the coronal suture has a female preponderance (2:1). Although environmental and genetic factors contribute to SSC, the etiology of the majority of SSC cases remains unclear. In this study, 227 primary calvarial osteoblast cell lines from patients with coronal, metopic, or sagittal synostosis and unaffected controls were established and assayed for ALP activity and BrdU incorporation (n=226) as respective measures of early stage osteoblast differentiation and proliferation. Primary osteoblast cell lines from individuals with sagittal synostosis demonstrated higher levels of ALP activity and reduced proliferation when compared to control lines. In order to address the sex differences in SSC types, the data was further stratified by sex. Osteoblasts from males and females with sagittal synostosis as well as males with metopic synostosis demonstrated higher levels of ALP activity when compared to sex matched controls, and males with sagittal or metopic synostosis demonstrated reduced levels of proliferation. In order to elucidate genes and pathways involved in these observed phenotypes, correlation analyses comparing ALP activity and proliferation to global gene expression was performed. Transcripts related to osteoblast differentiation were identified both differentially up and down regulated, correlated with ALP activity when compared to controls, and demonstrated a striking sex specific gene expression pattern. These data support that the dysregulation of osteoblast differentiation plays a role in the development of SSC and that genetic factors contribute to the observed sex related differences. PMID:25753363

  9. Caste-Specific and Sex-Specific Expression of Chemoreceptor Genes in a Termite.

    PubMed

    Mitaka, Yuki; Kobayashi, Kazuya; Mikheyev, Alexander; Tin, Mandy M Y; Watanabe, Yutaka; Matsuura, Kenji

    2016-01-01

    The sophisticated colony organization of eusocial insects is primarily maintained through the utilization of pheromones. The regulation of these complex social interactions requires intricate chemoreception systems. The recent publication of the genome of Zootermopsis nevadensis opened a new avenue to study molecular basis of termite caste systems. Although there has been a growing interest in the termite chemoreception system that regulates their sophisticated caste system, the relationship between division of labor and expression of chemoreceptor genes remains to be explored. Using high-throughput mRNA sequencing (RNA-seq), we found several chemoreceptors that are differentially expressed among castes and between sexes in a subterranean termite Reticulitermes speratus. In total, 53 chemoreception-related genes were annotated, including 22 odorant receptors, 7 gustatory receptors, 12 ionotropic receptors, 9 odorant-binding proteins, and 3 chemosensory proteins. Most of the chemoreception-related genes had caste-related and sex-related expression patterns; in particular, some chemoreception genes showed king-biased or queen-biased expression patterns. Moreover, more than half of the genes showed significant age-dependent differences in their expression in female and/or male reproductives. These results reveal a strong relationship between the evolution of the division of labor and the regulation of chemoreceptor gene expression, thereby demonstrating the chemical communication and underlining chemoreception mechanism in social insects.

  10. Caste-Specific and Sex-Specific Expression of Chemoreceptor Genes in a Termite

    PubMed Central

    Mikheyev, Alexander; Tin, Mandy M. Y.; Watanabe, Yutaka; Matsuura, Kenji

    2016-01-01

    The sophisticated colony organization of eusocial insects is primarily maintained through the utilization of pheromones. The regulation of these complex social interactions requires intricate chemoreception systems. The recent publication of the genome of Zootermopsis nevadensis opened a new avenue to study molecular basis of termite caste systems. Although there has been a growing interest in the termite chemoreception system that regulates their sophisticated caste system, the relationship between division of labor and expression of chemoreceptor genes remains to be explored. Using high-throughput mRNA sequencing (RNA-seq), we found several chemoreceptors that are differentially expressed among castes and between sexes in a subterranean termite Reticulitermes speratus. In total, 53 chemoreception-related genes were annotated, including 22 odorant receptors, 7 gustatory receptors, 12 ionotropic receptors, 9 odorant-binding proteins, and 3 chemosensory proteins. Most of the chemoreception-related genes had caste-related and sex-related expression patterns; in particular, some chemoreception genes showed king-biased or queen-biased expression patterns. Moreover, more than half of the genes showed significant age-dependent differences in their expression in female and/or male reproductives. These results reveal a strong relationship between the evolution of the division of labor and the regulation of chemoreceptor gene expression, thereby demonstrating the chemical communication and underlining chemoreception mechanism in social insects. PMID:26760975

  11. Bisphenol A modulates expression of sex differentiation genes in the self-fertilizing fish, Kryptolebias marmoratus.

    PubMed

    Rhee, Jae-Sung; Kim, Bo-Mi; Lee, Chang Joo; Yoon, Yong-Dal; Lee, Young-Mi; Lee, Jae-Seong

    2011-08-01

    Endocrine disrupting chemicals (EDCs) have been a major concern in the normal reproduction and development of aquatic organisms. In the teleost, steroid hormones are synthesized via the steroidogenesis pathway, and play a key physiological role in the regulation of gonadal sex differentiation. The protogynous hermaphroditic fish, Kryptolebias marmoratus is the only vertebrate capable of reproducing through internal self-fertilization. To uncover the effect of bisphenol A (BPA) on sex differentiation genes on transcription, we investigated the expression patterns of several sex differentiation-related genes such as dax1, dmrt1, mis, sf1, figlα, StAR and wt1 after BPA exposure with controls (E2 and TMX). In response to 17β-estradiol (E2) exposure, a testis-specific gene, dmrt1 mRNA was down-regulated in the gonad of the secondary male but the expression of the female-specific gene, dax1 mRNA was significantly elevated in the brain and gonad. A high level of StAR mRNA was detected in the brain and gonad of both hermaphrodite and secondary males, suggesting that the elevated expression of dax1 and StAR genes would be involved in E2 exposure. As expected, upon BPA exposure, the dmrt1 and MIS mRNA level decreased in both hermaphrodite and secondary males, while the female-specific gene, figlα mRNA level increased in the gonad of both genders. BPA showed an opposite mode of action on the expression of dax1 (induction, P>0.05) and sf1 mRNA (inhibition, P>0.05) in the brain and gonad against both genders. The sensitivity of dax1 to BPA on expression was relatively high in the secondary male. The wt1 mRNA was up-regulated in most tissues except in the liver of BPA-exposed secondary males. Regarding the time course study, the figlα mRNA level increased at 6 h after BPA exposure. In addition, BPA elevated the expression of StAR, dax1, and wt1 mRNA but repressed sf1 mRNA. In this paper, we demonstrated that BPA may modulate the expression of sex differentiation and

  12. Sex-biased gene expression and sequence conservation in Atlantic and Pacific salmon lice (Lepeophtheirus salmonis).

    PubMed

    Poley, Jordan D; Sutherland, Ben J G; Jones, Simon R M; Koop, Ben F; Fast, Mark D

    2016-07-04

    Salmon lice, Lepeophtheirus salmonis (Copepoda: Caligidae), are highly important ectoparasites of farmed and wild salmonids, and cause multi-million dollar losses to the salmon aquaculture industry annually. Salmon lice display extensive sexual dimorphism in ontogeny, morphology, physiology, behavior, and more. Therefore, the identification of transcripts with differential expression between males and females (sex-biased transcripts) may help elucidate the relationship between sexual selection and sexually dimorphic characteristics. Sex-biased transcripts were identified from transcriptome analyses of three L. salmonis populations, including both Atlantic and Pacific subspecies. A total of 35-43 % of all quality-filtered transcripts were sex-biased in L. salmonis, with male-biased transcripts exhibiting higher fold change than female-biased transcripts. For Gene Ontology and functional analyses, a consensus-based approach was used to identify concordantly differentially expressed sex-biased transcripts across the three populations. A total of 127 male-specific transcripts (i.e. those without detectable expression in any female) were identified, and were enriched with reproductive functions (e.g. seminal fluid and male accessory gland proteins). Other sex-biased transcripts involved in morphogenesis, feeding, energy generation, and sensory and immune system development and function were also identified. Interestingly, as observed in model systems, male-biased L. salmonis transcripts were more frequently without annotation compared to female-biased or unbiased transcripts, suggesting higher rates of sequence divergence in male-biased transcripts. Transcriptome differences between male and female L. salmonis described here provide key insights into the molecular mechanisms controlling sexual dimorphism in L. salmonis. This analysis offers targets for parasite control and provides a foundation for further analyses exploring critical topics such as the interaction

  13. FOXL2 is a female sex-determining gene in the goat.

    PubMed

    Boulanger, Laurent; Pannetier, Maëlle; Gall, Laurence; Allais-Bonnet, Aurélie; Elzaiat, Maëva; Le Bourhis, Daniel; Daniel, Nathalie; Richard, Christophe; Cotinot, Corinne; Ghyselinck, Norbert B; Pailhoux, Eric

    2014-02-17

    The origin of sex reversal in XX goats homozygous for the polled intersex syndrome (PIS) mutation was unclear because of the complexity of the mutation that affects the transcription of both FOXL2 and several long noncoding RNAs (lncRNAs). Accumulating evidence suggested that FOXL2 could be the sole gene of the PIS locus responsible for XX sex reversal, the lncRNAs being involved in transcriptional regulation of FOXL2. In this study, using zinc-finger nuclease-directed mutagenesis, we generated several fetuses, of which one XX individual bears biallelic mutations of FOXL2. Our analysis demonstrates that FOXL2 loss of function dissociated from loss of lncRNA expression is sufficient to cause an XX female-to-male sex reversal in the goat model and, as in the mouse model, an agenesis of eyelids. Both developmental defects were reproduced in two newborn animals cloned from the XX FOXL2(-/-) fibroblasts. These results therefore identify FOXL2 as a bona fide female sex-determining gene in the goat. They also highlight a stage-dependent role of FOXL2 in the ovary, different between goats and mice, being important for fetal development in the former but for postnatal maintenance in the latter. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. The Sex Determination Gene transformer Regulates Male-Female Differences in Drosophila Body Size

    PubMed Central

    Rideout, Elizabeth J.; Narsaiya, Marcus S.; Grewal, Savraj S.

    2015-01-01

    Almost all animals show sex differences in body size. For example, in Drosophila, females are larger than males. Although Drosophila is widely used as a model to study growth, the mechanisms underlying this male-female difference in size remain unclear. Here, we describe a novel role for the sex determination gene transformer (tra) in promoting female body growth. Normally, Tra is expressed only in females. We find that loss of Tra in female larvae decreases body size, while ectopic Tra expression in males increases body size. Although we find that Tra exerts autonomous effects on cell size, we also discovered that Tra expression in the fat body augments female body size in a non cell-autonomous manner. These effects of Tra do not require its only known targets doublesex and fruitless. Instead, Tra expression in the female fat body promotes growth by stimulating the secretion of insulin-like peptides from insulin producing cells in the brain. Our data suggest a model of sex-specific growth in which body size is regulated by a previously unrecognized branch of the sex determination pathway, and identify Tra as a novel link between sex and the conserved insulin signaling pathway. PMID:26710087

  15. The Sex Determination Gene transformer Regulates Male-Female Differences in Drosophila Body Size.

    PubMed

    Rideout, Elizabeth J; Narsaiya, Marcus S; Grewal, Savraj S

    2015-12-01

    Almost all animals show sex differences in body size. For example, in Drosophila, females are larger than males. Although Drosophila is widely used as a model to study growth, the mechanisms underlying this male-female difference in size remain unclear. Here, we describe a novel role for the sex determination gene transformer (tra) in promoting female body growth. Normally, Tra is expressed only in females. We find that loss of Tra in female larvae decreases body size, while ectopic Tra expression in males increases body size. Although we find that Tra exerts autonomous effects on cell size, we also discovered that Tra expression in the fat body augments female body size in a non cell-autonomous manner. These effects of Tra do not require its only known targets doublesex and fruitless. Instead, Tra expression in the female fat body promotes growth by stimulating the secretion of insulin-like peptides from insulin producing cells in the brain. Our data suggest a model of sex-specific growth in which body size is regulated by a previously unrecognized branch of the sex determination pathway, and identify Tra as a novel link between sex and the conserved insulin signaling pathway.

  16. Free flight odor tracking in Drosophila: Effect of wing chemosensors, sex and pheromonal gene regulation.

    PubMed

    Houot, Benjamin; Gigot, Vincent; Robichon, Alain; Ferveur, Jean-François

    2017-01-09

    The evolution of powered flight in insects had major consequences for global biodiversity and involved the acquisition of adaptive processes allowing individuals to disperse to new ecological niches. Flies use both vision and olfactory input from their antennae to guide their flight; chemosensors on fly wings have been described, but their function remains mysterious. We studied Drosophila flight in a wind tunnel. By genetically manipulating wing chemosensors, we show that these structures play an essential role in flight performance with a sex-specific effect. Pheromonal systems are also involved in Drosophila flight guidance: transgenic expression of the pheromone production and detection gene, desat1, produced low, rapid flight that was absent in control flies. Our study suggests that the sex-specific modulation of free-flight odor tracking depends on gene expression in various fly tissues including wings and pheromonal-related tissues.

  17. Free flight odor tracking in Drosophila: Effect of wing chemosensors, sex and pheromonal gene regulation

    PubMed Central

    Houot, Benjamin; Gigot, Vincent; Robichon, Alain; Ferveur, Jean-François

    2017-01-01

    The evolution of powered flight in insects had major consequences for global biodiversity and involved the acquisition of adaptive processes allowing individuals to disperse to new ecological niches. Flies use both vision and olfactory input from their antennae to guide their flight; chemosensors on fly wings have been described, but their function remains mysterious. We studied Drosophila flight in a wind tunnel. By genetically manipulating wing chemosensors, we show that these structures play an essential role in flight performance with a sex-specific effect. Pheromonal systems are also involved in Drosophila flight guidance: transgenic expression of the pheromone production and detection gene, desat1, produced low, rapid flight that was absent in control flies. Our study suggests that the sex-specific modulation of free-flight odor tracking depends on gene expression in various fly tissues including wings and pheromonal-related tissues. PMID:28067325

  18. The expression of select genes necessary for membrane-associated estrogen receptor signaling differ by sex in adult rat hippocampus.

    PubMed

    Meitzen, John; Britson, Kyla A; Tuomela, Krista; Mermelstein, Paul G

    2017-09-28

    17β-estradiol can rapidly modulate neuron function via membrane estrogen receptors (ERs) in a sex-specific manner. For example, female rat hippocampal neurons express palmitoylated versions of ERα and ERβ that associate with the plasma membrane. These membrane-associated ERs are organized by caveolin proteins into functional signaling microdomains with metabotropic glutamate receptors (mGluRs). ER/mGluR signaling mediates several sex-specific estradiol actions on hippocampal neuron function. An important unanswered question regards the mechanism by which sex-specific membrane-associated ER signaling is generated, especially since it has been previously demonstrated that mGluR action is not sex-specific. One possibility is that the genes necessary for the ER membrane complex are differentially expressed between males and females, including genes that encode ERα and β, caveolin 1 and 3, and/or the palmitoylacyltransferases DHHC-7 and -21. Thus we used qPCR to test the hypothesis that these genes show sex differences in expression in neonatal and adult rat hippocampus. As an additional control we tested the expression of the 20 other DHHC palmitoylacyltransferases with no known connections to ER. In neonatal hippocampus, no sex differences were detected in gene expression. In adult hippocampus, the genes that encode caveolin 1 and DHHC-7 showed decreased expression in females compared to males. Thus, select genes differ by sex at specific developmental stages, arguing for a more nuanced model than simple widespread perinatal emergence of sex differences in all genes enabling sex-specific estradiol action. These findings enable the generation of new hypotheses regarding the mechanisms by which sex differences in membrane-associated ER signaling are programmed. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Sex-biased gene expression in the brown alga Fucus vesiculosus.

    PubMed

    Martins, Maria João F; Mota, Catarina F; Pearson, Gareth A

    2013-05-01

    The fucoid brown algae (Heterokontophyta, Phaeophyceae) are increasingly the focus of ecological genetics, biodiversity, biogeography and speciation research. The molecular genetics underlying mating system variation, where repeated dioecious - hermaphrodite switches during evolution are recognized, and the molecular evolution of sex-related genes are key questions currently hampered by a lack of genomic information. We therefore undertook a comparative analysis of male and female reproductive tissue transcriptomes against a vegetative background during natural reproductive cycles in Fucus vesiculosus. Over 300 k reads were assembled and annotated against public protein databases including a brown alga. Compared with the vegetative tissue, photosynthetic and carbohydrate metabolism pathways were under-expressed, particularly in male tissue, while several pathways involved in genetic information processing and replication were over-expressed. Estimates of sex-biased gene (SBG) expression were higher for male (14% of annotated orthologues) than female tissue (9%) relative to the vegetative background. Mean expression levels and variance were also greater in male- than female-biased genes. Major female-biased genes were carbohydrate-modifying enzymes with likely roles in zygote cell wall biogenesis and/or modification. Male-biased genes reflected distinct sperm development and function, and orthologues for signal perception (a phototropin), transduction (several kinases), and putatively flagella-localized proteins (including candidate gamete-recognition proteins) were uniquely expressed in males. Overall, the results suggest constraint on female-biased genes (possible pleiotropy), and less constrained male-biased genes, mostly associated with sperm-specific functions. Our results support the growing contention that males possess a large array of genes regulating male fitness, broadly supporting findings in evolutionarily distant heterogametic animal models. This work

  20. Sex-biased gene expression in the brown alga Fucus vesiculosus

    PubMed Central

    2013-01-01

    Background The fucoid brown algae (Heterokontophyta, Phaeophyceae) are increasingly the focus of ecological genetics, biodiversity, biogeography and speciation research. The molecular genetics underlying mating system variation, where repeated dioecious – hermaphrodite switches during evolution are recognized, and the molecular evolution of sex-related genes are key questions currently hampered by a lack of genomic information. We therefore undertook a comparative analysis of male and female reproductive tissue transcriptomes against a vegetative background during natural reproductive cycles in Fucus vesiculosus. Results Over 300 k reads were assembled and annotated against public protein databases including a brown alga. Compared with the vegetative tissue, photosynthetic and carbohydrate metabolism pathways were under-expressed, particularly in male tissue, while several pathways involved in genetic information processing and replication were over-expressed. Estimates of sex-biased gene (SBG) expression were higher for male (14% of annotated orthologues) than female tissue (9%) relative to the vegetative background. Mean expression levels and variance were also greater in male- than female-biased genes. Major female-biased genes were carbohydrate-modifying enzymes with likely roles in zygote cell wall biogenesis and/or modification. Male-biased genes reflected distinct sperm development and function, and orthologues for signal perception (a phototropin), transduction (several kinases), and putatively flagella-localized proteins (including candidate gamete-recognition proteins) were uniquely expressed in males. Overall, the results suggest constraint on female-biased genes (possible pleiotropy), and less constrained male-biased genes, mostly associated with sperm-specific functions. Conclusions Our results support the growing contention that males possess a large array of genes regulating male fitness, broadly supporting findings in evolutionarily distant

  1. Contribution of domestic animals to the identification of new genes involved in sex determination.

    PubMed

    Pailhoux, E; Vigier, B; Vaiman, D; Schibler, L; Vaiman, A; Cribiu, E; Nezer, C; Georges, M; Sundström, J; Pelliniemi, L J; Fellous, M; Cotinot, C

    2001-12-01

    Among farm animals, two species present an intersex condition at a relatively high frequency: pig and goat. Both are known to contain XX sex-reversed individuals which are genetically female but with a true hermaphrodite or male phenotype. It has been clearly demonstrated that the SRY gene is not involved in these phenotypes. Consequently, autosomal or X-linked mutations in the sex-determining pathway may explain these sex-reversed phenotypes. A mutation referred to as "polled" has been characterized in goats by the suppression of horn formation and abnormal sexual differentiation. The Polled Intersex Syndrome locus (PIS) was initially located in the distal region of goat chromosome 1. The homologous human region has been precisely identified as an HSA 3q23 DNA segment containing the Blepharophimosis Ptosis Epicanthus locus (BPES), a syndrome combining Premature Ovarian Failure (POF) and an excess of epidermis of the eyelids. In order to isolate genes involved in pig intersexuality, a similar genetic approach was attempted in pigs using genome scanning of resource families. Genetic analyses suggest that pig intersexuality is controlled multigenically. Parallel to this work, gonads of fetal intersex animals have been studied during development by light and electron microscopy. The development of testicular tissue and reduction of germ cell number by apoptosis, which simultaneously occurs as soon as 50 days post coïtum, also suggests that several separate genes could be involved in pig intersexuality.

  2. Sex differences in gene expression for pupa weight in long term selected lines of Tribolium.

    PubMed

    Enfield, F D; Hartung, N; Hefeneider, S H

    1975-03-01

    Full-sib matings in two populations of Tribolium which had been selected for increased pupa weight for more than 85 generations resulted in a significant inbreeding depression in male progeny but showed no effect in the female progeny. An analysis of variance of a population produced by backcrossing the selected populations to the inbred lines originally used to establish the select populations (Design-III) indicated some genes were still segregating which produce dominance effects in males but not in females. The data support the hypothesis that a class of genes exists, associated with the autosomes, that differ in their dominance effects of pupa weight in the two sexes.

  3. Sex Chromosome-wide Transcriptional Suppression and Compensatory Cis-Regulatory Evolution Mediate Gene Expression in the Drosophila Male Germline

    PubMed Central

    Landeen, Emily L.; Muirhead, Christina A.; Meiklejohn, Colin D.; Presgraves, Daven C.

    2016-01-01

    The evolution of heteromorphic sex chromosomes has repeatedly resulted in the evolution of sex chromosome-specific forms of regulation, including sex chromosome dosage compensation in the soma and meiotic sex chromosome inactivation in the germline. In the male germline of Drosophila melanogaster, a novel but poorly understood form of sex chromosome-specific transcriptional regulation occurs that is distinct from canonical sex chromosome dosage compensation or meiotic inactivation. Previous work shows that expression of reporter genes driven by testis-specific promoters is considerably lower—approximately 3-fold or more—for transgenes inserted into X chromosome versus autosome locations. Here we characterize this transcriptional suppression of X-linked genes in the male germline and its evolutionary consequences. Using transgenes and transpositions, we show that most endogenous X-linked genes, not just testis-specific ones, are transcriptionally suppressed several-fold specifically in the Drosophila male germline. In wild-type testes, this sex chromosome-wide transcriptional suppression is generally undetectable, being effectively compensated by the gene-by-gene evolutionary recruitment of strong promoters on the X chromosome. We identify and experimentally validate a promoter element sequence motif that is enriched upstream of the transcription start sites of hundreds of testis-expressed genes; evolutionarily conserved across species; associated with strong gene expression levels in testes; and overrepresented on the X chromosome. These findings show that the expression of X-linked genes in the Drosophila testes reflects a balance between chromosome-wide epigenetic transcriptional suppression and long-term compensatory adaptation by sex-linked genes. Our results have broad implications for the evolution of gene expression in the Drosophila male germline and for genome evolution. PMID:27404402

  4. Sex Chromosome-wide Transcriptional Suppression and Compensatory Cis-Regulatory Evolution Mediate Gene Expression in the Drosophila Male Germline.

    PubMed

    Landeen, Emily L; Muirhead, Christina A; Wright, Lori; Meiklejohn, Colin D; Presgraves, Daven C

    2016-07-01

    The evolution of heteromorphic sex chromosomes has repeatedly resulted in the evolution of sex chromosome-specific forms of regulation, including sex chromosome dosage compensation in the soma and meiotic sex chromosome inactivation in the germline. In the male germline of Drosophila melanogaster, a novel but poorly understood form of sex chromosome-specific transcriptional regulation occurs that is distinct from canonical sex chromosome dosage compensation or meiotic inactivation. Previous work shows that expression of reporter genes driven by testis-specific promoters is considerably lower-approximately 3-fold or more-for transgenes inserted into X chromosome versus autosome locations. Here we characterize this transcriptional suppression of X-linked genes in the male germline and its evolutionary consequences. Using transgenes and transpositions, we show that most endogenous X-linked genes, not just testis-specific ones, are transcriptionally suppressed several-fold specifically in the Drosophila male germline. In wild-type testes, this sex chromosome-wide transcriptional suppression is generally undetectable, being effectively compensated by the gene-by-gene evolutionary recruitment of strong promoters on the X chromosome. We identify and experimentally validate a promoter element sequence motif that is enriched upstream of the transcription start sites of hundreds of testis-expressed genes; evolutionarily conserved across species; associated with strong gene expression levels in testes; and overrepresented on the X chromosome. These findings show that the expression of X-linked genes in the Drosophila testes reflects a balance between chromosome-wide epigenetic transcriptional suppression and long-term compensatory adaptation by sex-linked genes. Our results have broad implications for the evolution of gene expression in the Drosophila male germline and for genome evolution.

  5. Identification of floral genes for sex determination in Calamus palustris Griff. by using suppression subtractive hybridization.

    PubMed

    Ng, C Y; Wickneswari, R; Choong, C Y

    2014-08-07

    Calamus palustris Griff. is an economically important dioecious rattan species in Southeast Asia. However, dioecy and onset of flowering at 3-4 years old render uncertainties in desired female:male seedling ratios to establish a productive seed orchard for this rattan species. We constructed a subtractive library for male floral tissue to understand the genetic mechanism for gender determination in C. palustris. The subtractive library produced 1536 clones with 1419 clones of high quality. Reverse Northern screening showed 313 clones with differential expression, and sequence analyses clustered them into 205 unigenes, including 32 contigs and 173 singletons. The subtractive library was further validated with reverse transcription-quantitative polymerase chain reaction analysis. Homology identification classified the unigenes into 12 putative functional proteins with 83% unigenes showing significant match to proteins in databases. Functional annotations of these unigenes revealed genes involved in male flower development, including MADS-box genes, pollen-related genes, phytohormones for flower development, and male flower organ development. Our results showed that the male floral genes may play a vital role in sex determination in C. palustris. The identified genes can be exploited to understand the molecular basis of sex determination in C. palustris.

  6. Influence of sex and genetic variability on expression of X-linked genes in human monocytes.

    PubMed

    Castagné, Raphaële; Zeller, Tanja; Rotival, Maxime; Szymczak, Silke; Truong, Vinh; Schillert, Arne; Trégouët, David-Alexandre; Münzel, Thomas; Ziegler, Andreas; Cambien, François; Blankenberg, Stefan; Tiret, Laurence

    2011-11-01

    In humans, the fraction of X-linked genes with higher expression in females has been estimated to be 5% from microarray studies, a proportion lower than the 25% of genes thought to escape X inactivation. We analyzed 715 X-linked transcripts in circulating monocytes from 1,467 subjects and found an excess of female-biased transcripts on the X compared to autosomes (9.4% vs 5.5%, p<2×10(-5)). Among the genes not previously known to escape inactivation, the most significant one was EFHC2 whose 20% of variability was explained by sex. We also investigated cis expression quantitative trait loci (eQTLs) by analyzing 15,703 X-linked SNPs. The frequency and magnitude of X-linked cis eQTLs were quite similar in males and females. Few genes exhibited a stronger genetic effect in females than in males (ARSD, DCX, POLA1 and ITM2A). These genes would deserve further investigation since they may contribute to sex pathophysiological differences. Copyright © 2011 Elsevier Inc. All rights reserved.

  7. Isolation of differentially expressed sex genes in garden asparagus using suppression subtractive hybridization.

    PubMed

    Deng, Chuan-liang; Wang, Ning-na; Li, Shu-fen; Dong, Tian-yu; Zhao, Xin-peng; Wang, Shao-jing; Gao, Wu-jun; Lu, Long-dou

    2015-09-01

    Garden asparagus (Asparagus officinalis L.) is a dioecious species whose male and female flowers are found in separate unisexual individuals. A region called the M-locus, located on a pair of homomorphic sex chromosomes, controls sexual dimorphism in asparagus. To date, no sex determining gene has been isolated from asparagus. To identify more genes involved in flower development in asparagus, subtractive hybridization library of male flowers in asparagus was constructed by suppression subtraction hybridization. A total of 107 expressed sequence tags (ESTs) were identified. BLASTX analysis showed that the library contained several genes that could be related to flower development. The expression patterns of seven selected genes believed to be involved in the development of asparagus male flower were further analyzed by semi-quantitative or real-time reverse-transcription polymerase chain reaction (RT-PCR). Results showed that AOEST4-5, AOEST12-40, and AOEST13-38 were strongly expressed in the male flower stage, whereas no transcript level of AOEST13-38 was detected in the female flower stage. The expression levels of AOEST13-87, AOEST13-92, AOEST13-40, and AOEST18-87 in the male flower stage were also higher than those in the female flower stage, although these transcripts were also expressed in other tissues. The identified genes can provide a strong starting point for further studies on the underlying molecular differences between the male and female flowers of asparagus.

  8. Evolution of the insect body plan as revealed by the Sex combs reduced expression pattern.

    PubMed

    Rogers, B T; Peterson, M D; Kaufman, T C

    1997-01-01

    The products of the HOM/Hox homeotic genes form a set of evolutionarily conserved transcription factors that control elaborate developmental processes and specify cell fates in many metazoans. We examined the expression of the ortholog of the homeotic gene Sex combs reduced (Scr) of Drosophila melanogaster in insects of three divergent orders: Hemiptera, Orthoptera and Thysanura. Our data reflect how the conservation and variation of Scr expression has affected the morphological evolution of insects. Whereas the anterior epidermal expression of Scr, in a small part of the posterior maxillary and all of the labial segment, is found to be in common among all four insect orders, the posterior (thoracic) expression domains vary. Unlike what is observed in flies, the Scr orthologs of other insects are not expressed broadly over the first thoracic segment, but are restricted to small patches. We show here that Scr is required for suppression of wings on the prothorax of Drosophila. Moreover, Scr expression at the dorsal base of the prothoracic limb in two other winged insects, crickets (Orthoptera) and milkweed bugs (Hemiptera), is consistent with Scr acting as a suppressor of prothoracic wings in these insects. Scr is also expressed in a small patch of cells near the basitarsal-tibial junction of milkweed bugs, precisely where a leg comb develops, suggesting that Scr promotes comb formation, as it does in Drosophila. Surprisingly, the dorsal prothoracic expression of Scr is also present in the primitively wingless firebrat (Thysanura) and the leg patch is seen in crickets, which have no comb. Mapping both gene expression patterns and morphological characters onto the insect phylogenetic tree demonstrates that in the cases of wing suppression and comb formation the appearance of expression of Scr in the prothorax apparently precedes these specific functions.

  9. A Novel Candidate Gene for Temperature-Dependent Sex Determination in the Common Snapping Turtle.

    PubMed

    Schroeder, Anthony L; Metzger, Kelsey J; Miller, Alexandra; Rhen, Turk

    2016-05-01

    Temperature-dependent sex determination (TSD) was described nearly 50 years ago. Researchers have since identified many genes that display differential expression at male- vs. female-producing temperatures. Yet, it is unclear whether these genes (1) are involved in sex determination per se, (2) are downstream effectors involved in differentiation of ovaries and testes, or (3) are thermo-sensitive but unrelated to gonad development. Here we present multiple lines of evidence linking CIRBP to sex determination in the snapping turtle, Chelydra serpentina We demonstrate significant associations between a single nucleotide polymorphism (SNP) (c63A > C) in CIRBP, transcript levels in embryonic gonads during specification of gonad fate, and sex in hatchlings from a thermal regime that produces mixed sex ratios. The A allele was induced in embryos exposed to a female-producing temperature, while expression of the C allele did not differ between female- and male-producing temperatures. In accord with this pattern of temperature-dependent, allele-specific expression, AA homozygotes were more likely to develop ovaries than AC heterozygotes, which, in turn, were more likely to develop ovaries than CC homozygotes. Multiple regression using SNPs in CIRBP and adjacent loci suggests that c63A > C may be the causal variant or closely linked to it. Differences in CIRBP allele frequencies among turtles from northern Minnesota, southern Minnesota, and Texas reflect small and large-scale latitudinal differences in TSD pattern. Finally, analysis of CIRBP protein localization reveals that CIRBP is in a position to mediate temperature effects on the developing gonads. Together, these studies strongly suggest that CIRBP is involved in determining the fate of the bipotential gonad.

  10. Sequence length polymorphisms within primate amelogenin and amelogenin-like genes: usefulness in sex determination.

    PubMed

    Morrill, Benson H; Rickords, Lee F; Schafstall, Heather J

    2008-10-01

    Sequence length polymorphisms between the amelogenin (AMELX) and the amelogenin-like (AMELY) genes both within and between several mammalian species have been identified and utilized for sex determination, species identification, and to elucidate evolutionary relationships. Sex determination via polymerase chain reaction (PCR) assays of the AMELX and AMELY genes has been successful in greater apes, prosimians, and two species of old world monkeys. To date, no sex determination PCR assay using AMELX and AMELY has been developed for new world monkeys. In this study, we present partial AMELX and AMELY sequences for five old world monkey species (Mandrillus sphinx, Macaca nemestrina, Macaca fuscata, Macaca mulatta, and Macaca fascicularis) along with primer sets that can be used for sex determination of these five species. In addition, we compare the sequences we generated with other primate AMELX and AMELY sequences available on GenBank and discuss sequence length polymorphisms and their usefulness in sex determination within primates. The mandrill and four species of macaque all share two similar deletion regions with each other, the human, and the chimpanzee in the region sequenced. These two deletion regions are 176-181 and 8 nucleotides in length. In analyzing existing primate sequences on GenBank, we also discovered that a separate six-nucleotide polymorphism located approximately 300 nucleotides upstream of the 177 nucleotide polymorphism in sequences of humans and chimps was also present in two species of new world monkeys (Saimiri boliviensis and Saimiri sciureus). We designed primers that incorporate this polymorphism, creating the first AMELX and AMELY PCR primer set that has been used successfully to generate two bands in a new world monkey species.

  11. A Novel Candidate Gene for Temperature-Dependent Sex Determination in the Common Snapping Turtle

    PubMed Central

    Schroeder, Anthony L.; Metzger, Kelsey J.; Miller, Alexandra; Rhen, Turk

    2016-01-01

    Temperature-dependent sex determination (TSD) was described nearly 50 years ago. Researchers have since identified many genes that display differential expression at male- vs. female-producing temperatures. Yet, it is unclear whether these genes (1) are involved in sex determination per se, (2) are downstream effectors involved in differentiation of ovaries and testes, or (3) are thermo-sensitive but unrelated to gonad development. Here we present multiple lines of evidence linking CIRBP to sex determination in the snapping turtle, Chelydra serpentina. We demonstrate significant associations between a single nucleotide polymorphism (SNP) (c63A > C) in CIRBP, transcript levels in embryonic gonads during specification of gonad fate, and sex in hatchlings from a thermal regime that produces mixed sex ratios. The A allele was induced in embryos exposed to a female-producing temperature, while expression of the C allele did not differ between female- and male-producing temperatures. In accord with this pattern of temperature-dependent, allele-specific expression, AA homozygotes were more likely to develop ovaries than AC heterozygotes, which, in turn, were more likely to develop ovaries than CC homozygotes. Multiple regression using SNPs in CIRBP and adjacent loci suggests that c63A > C may be the causal variant or closely linked to it. Differences in CIRBP allele frequencies among turtles from northern Minnesota, southern Minnesota, and Texas reflect small and large-scale latitudinal differences in TSD pattern. Finally, analysis of CIRBP protein localization reveals that CIRBP is in a position to mediate temperature effects on the developing gonads. Together, these studies strongly suggest that CIRBP is involved in determining the fate of the bipotential gonad. PMID:26936926

  12. The gene Sex-lethal of the Sciaridae family (order Diptera, suborder Nematocera) and its phylogeny in dipteran insects.

    PubMed

    Serna, Esther; Gorab, Eduardo; Ruiz, M Fernanda; Goday, Clara; Eirín-López, José M; Sánchez, Lucas

    2004-10-01

    This article reports the cloning and characterization of the gene homologous to Sex-lethal (Sxl) of Drosophila melanogaster from Sciara coprophila, Rhynchosciara americana, and Trichosia pubescens. This gene plays the key role in controlling sex determination and dosage compensation in D. melanogaster. The Sxl gene of the three species studied produces a single transcript encoding a single protein in both males and females. Comparison of the Sxl proteins of these Nematocera insects with those of the Brachycera showed their two RNA-binding domains (RBD) to be highly conserved, whereas significant variation was observed in both the N- and C-terminal domains. The great majority of nucleotide changes in the RBDs were synonymous, indicating that purifying selection is acting on them. In both sexes of the three Nematocera insects, the Sxl protein colocalized with transcription-active regions dependent on RNA polymerase II but not on RNA polymerase I. Together, these results indicate that Sxl does not appear to play a discriminatory role in the control of sex determination and dosage compensation in nematocerans. Thus, in the phylogenetic lineage that gave rise to the drosophilids, evolution coopted for the Sxl gene, modified it, and converted it into the key gene controlling sex determination and dosage compensation. At the same time, however, certain properties of the recruited ancestral Sxl gene were beneficial, and these are maintained in the evolved Sxl gene, allowing it to exert its sex-determining and dose compensation functions in Drosophila.

  13. Importance of the COMT gene for sex differences in brain function and predisposition to psychiatric disorders.

    PubMed

    Tunbridge, Elizabeth M; Harrison, Paul J

    2011-01-01

    As outlined elsewhere in this volume, sex differences can affect brain function and its dysfunction in psychiatric disorders. It is known that genetic factors contribute to these sex dimorphisms, but the individual genes have rarely been identified. The catechol-O-methyltransferase (COMT) gene, which encodes an enzyme that metabolises catechol compounds, including dopamine, is a leading candidate in this regard. COMT's enzyme activity, and the neurochemistry and behaviour of COMT knockout mice are both markedly sexually dimorphic. Furthermore, genetic associations between COMT and psychiatric phenotypes frequently show differences between men and women. Although many of these differences are unconfirmed or minor, some appear to be of reasonable robustness and magnitude and are reviewed in this chapter. Sexually dimorphic effects of COMT are usually attributed to transcriptional regulation by oestrogens; however, a careful examination of the literature suggests that additional mechanisms are likely to be at least as important. Here, we review the evidence for a sexually dimorphic influence of COMT upon psychiatric phenotypes and brain function, and discuss potential mechanisms by which this may occur. We conclude that despite the evidence being incomplete, there are accumulating and in places compelling data showing that COMT has markedly sexually dimorphic effects on brain function and its dysfunction in psychiatric disorders. Although oestrogenic regulation of COMT is probably partially responsible for these sex differences, other mechanisms are likely also involved. Since sex differences in the genetic architecture of brain function and psychiatric disorders are the rule not the exception, we anticipate that additional evidence will emerge for sexual dimorphisms, not only in COMT but also in many other autosomal genes.

  14. Determination of floral organ identity by Arabidopsis MADS domain homeotic proteins AP1, AP3, PI, and AG is independent of their DNA-binding specificity.

    PubMed Central

    Riechmann, J L; Meyerowitz, E M

    1997-01-01

    The MADS domain homeotic proteins APETALA1 (AP1), APETALA3 (AP3), PISTILLATA (PI), and AGAMOUS (AG) combinatorially specify the identity of Arabidopsis floral organs. AP1/AP1, AG/AG, and AP3/PI dimers bind to similar CArG box sequences; thus, differences in DNA-binding specificity among these proteins do not seem to be the origin of their distinct organ identity properties. To assess the overall contribution that specific DNA binding could make to their biological specificity, we have generated chimeric genes in which the amino-terminal half of the MADS domain of AP1, AP3, PI, and AG was substituted by the corresponding sequences of human SRF and MEF2A proteins. In vitro DNA-binding assays reveal that the chimeric proteins acquired the respective, and distinct, DNA-binding specificity of SRF or MEF2A. However, ectopic expression of the chimeric genes reproduces the dominant gain-of-function phenotypes exhibited by plants ectopically expressing the corresponding Arabidopsis wild-type genes. In addition, both the SRF and MEF2 chimeric genes can complement the pertinent ap1-1, ap3-3, pi-1, or ag-3 mutations to a degree similar to that of AP1, AP3, PI, and AG when expressed under the control of the same promoter. These results indicate that determination of floral organ identity by the MADS domain homeotic proteins AP1, AP3, PI, and AG is independent of their DNA-binding specificity. In addition, the DNA-binding experiments show that either one of the two MADS domains of a dimer can be sufficient to confer a particular DNA-binding specificity to the complex and that sequences outside the amino-terminal basic region of the MADS domain can, in some cases, contribute to the DNA-binding specificity of the proteins. Images PMID:9243505

  15. Evidence for Emergence of Sex-Determining Gene(s) in a Centromeric Region in Vasconcellea parviflora

    PubMed Central

    Iovene, Marina; Yu, Qingyi; Ming, Ray; Jiang, Jiming

    2015-01-01

    Sex chromosomes have been studied in many plant and animal species. However, few species are suitable as models to study the evolutionary histories of sex chromosomes. We previously demonstrated that papaya (Carica papaya) (2n = 2x = 18), a fruit tree in the family Caricaceae, contains recently emerged but cytologically heteromorphic X/Y chromosomes. We have been intrigued by the possible presence and evolution of sex chromosomes in other dioecious Caricaceae species. We selected a set of 22 bacterial artificial chromosome (BAC) clones that are distributed along the papaya X/Y chromosomes. These BACs were mapped to the meiotic pachytene chromosomes of Vasconcellea parviflora (2n = 2x = 18), a species that diverged from papaya ∼27 million years ago. We demonstrate that V. parviflora contains a pair of heteromorphic X/Y chromosomes that are homologous to the papaya X/Y chromosomes. The comparative mapping results revealed that the male-specific regions of the Y chromosomes (MSYs) probably initiated near the centromere of the Y chromosomes in both species. The two MSYs, however, shared only a small chromosomal domain near the centromere in otherwise rearranged chromosomes. The V. parviflora MSY expanded toward the short arm of the chromosome, whereas the papaya MSY expanded in the opposite direction. Most BACs mapped to papaya MSY were not located in V. parviflora MSY, revealing different DNA compositions in the two MSYs. These results suggest that mutation of gene(s) in the centromeric region may have triggered sex chromosome evolution in these plant species. PMID:25480779

  16. Developmental Analysis of Two Sex-Determining Genes, M and F, in the Housefly, Musca Domestica

    PubMed Central

    Hilfiker-Kleiner, D.; Dubendorfer, A.; Hilfiker, A.; Nothiger, R.

    1993-01-01

    In the housefly, Musca domestica, a single dominant factor, M, determines maleness. Animals hemior heterozygous for M are males, whereas those without M develop as females. In certain strains, however, both sexes are homozygous for M, and an epistatic dominant factor, F(D), dictates female development. The requirement for these factors was analyzed by producing, with mitotic recombination, mosaic animals consisting of genetically male and female cells. Removal of F(D) from an M/M;F(D)/+ cell at any time of larval development, even in the last larval instar, resulted in sex-reversal, i.e., in the development of a male clone in an otherwise female fly. In contrast, when M was removed from M/+ cells, the resulting clones remained male despite their female genotype, even when the removal of M happened at embryonic stages. The occurrence of spontaneous gynandromorphs, however, shows that the loss of M in individual nuclei prior to blastoderm formation causes the affected cells to adopt the female pathway. These results are consistent with the hypothesis that M is the primary sex-determining signal which sets the state of activity of the key gene F at around the blastoderm stage. Parallels and differences to the sex-determining system of Drosophila are discussed. PMID:8375655

  17. Sex-specific silencing of X-linked genes by Xist RNA.

    PubMed

    Gayen, Srimonta; Maclary, Emily; Hinten, Michael; Kalantry, Sundeep

    2016-01-19

    X-inactive specific transcript (Xist) long noncoding RNA (lncRNA) is thought to catalyze silencing of X-linked genes in cis during X-chromosome inactivation, which equalizes X-linked gene dosage between male and female mammals. To test the impact of Xist RNA on X-linked gene silencing, we ectopically induced endogenous Xist by ablating the antisense repressor Tsix in mice. We find that ectopic Xist RNA induction and subsequent X-linked gene silencing is sex specific in embryos and in differentiating embryonic stem cells (ESCs) and epiblast stem cells (EpiSCs). A higher frequency of X(ΔTsix)Y male cells displayed ectopic Xist RNA coating compared with X(ΔTsix)X female cells. This increase reflected the inability of X(ΔTsix)Y cells to efficiently silence X-linked genes compared with X(ΔTsix)X cells, despite equivalent Xist RNA induction and coating. Silencing of genes on both Xs resulted in significantly reduced proliferation and increased cell death in X(ΔTsix)X female cells relative to X(ΔTsix)Y male cells. Thus, whereas Xist RNA can inactivate the X chromosome in females it may not do so in males. We further found comparable silencing in differentiating X(ΔTsix)Y and 39,X(ΔTsix) (X(ΔTsix)O) ESCs, excluding the Y chromosome and instead implicating the X-chromosome dose as the source of the sex-specific differences. Because X(ΔTsix)X female embryonic epiblast cells and EpiSCs harbor an inactivated X chromosome prior to ectopic inactivation of the active X(ΔTsix) X chromosome, we propose that the increased expression of one or more X-inactivation escapees activates Xist and, separately, helps trigger X-linked gene silencing.

  18. Sex-specific silencing of X-linked genes by Xist RNA

    PubMed Central

    Gayen, Srimonta; Maclary, Emily; Hinten, Michael; Kalantry, Sundeep

    2016-01-01

    X-inactive specific transcript (Xist) long noncoding RNA (lncRNA) is thought to catalyze silencing of X-linked genes in cis during X-chromosome inactivation, which equalizes X-linked gene dosage between male and female mammals. To test the impact of Xist RNA on X-linked gene silencing, we ectopically induced endogenous Xist by ablating the antisense repressor Tsix in mice. We find that ectopic Xist RNA induction and subsequent X-linked gene silencing is sex specific in embryos and in differentiating embryonic stem cells (ESCs) and epiblast stem cells (EpiSCs). A higher frequency of XΔTsixY male cells displayed ectopic Xist RNA coating compared with XΔTsixX female cells. This increase reflected the inability of XΔTsixY cells to efficiently silence X-linked genes compared with XΔTsixX cells, despite equivalent Xist RNA induction and coating. Silencing of genes on both Xs resulted in significantly reduced proliferation and increased cell death in XΔTsixX female cells relative to XΔTsixY male cells. Thus, whereas Xist RNA can inactivate the X chromosome in females it may not do so in males. We further found comparable silencing in differentiating XΔTsixY and 39,XΔTsix (XΔTsixO) ESCs, excluding the Y chromosome and instead implicating the X-chromosome dose as the source of the sex-specific differences. Because XΔTsixX female embryonic epiblast cells and EpiSCs harbor an inactivated X chromosome prior to ectopic inactivation of the active XΔTsix X chromosome, we propose that the increased expression of one or more X-inactivation escapees activates Xist and, separately, helps trigger X-linked gene silencing. PMID:26739568

  19. The sex determination gene shows no founder effect in the giant honey bee, Apis dorsata.

    PubMed

    Liu, Zhi Yong; Wang, Zi Long; Yan, Wei Yu; Wu, Xiao Bo; Zeng, Zhi Jiang; Huang, Zachary Y

    2012-01-01

    All honey bee species (Apis spp) share the same sex determination mechanism using the complementary sex determination (csd) gene. Only individuals heterogeneous at the csd allele develop into females, and the homozygous develop into diploid males, which do not survive. The honeybees are therefore under selection pressure to generate new csd alleles. Previous studies have shown that the csd gene is under balancing selection. We hypothesize that due to the long separation from the mainland of Hainan Island, China, that the giant honey bees (Apis dorsata) should show a founder effect for the csd gene, with many different alleles clustered together, and these would be absent on the mainland. We sampled A. dorsata workers from both Hainan and Guangxi Provinces and then cloned and sequenced region 3 of the csd gene and constructed phylogenetic trees. We failed to find any clustering of the csd alleles according to their geographical origin, i.e. the Hainan and Guangxi samples did not form separate clades. Further analysis by including previously published csd sequences also failed to show any clade-forming in both the Philippines and Malaysia. Results from this study and those from previous studies did not support the expectations of a founder effect. We conclude that because of the extremely high mating frequency of A. dorsata queens, a founder effect does not apply in this species.

  20. The Sex Determination Gene Shows No Founder Effect in the Giant Honey Bee, Apis dorsata

    PubMed Central

    Yan, Wei Yu; Wu, Xiao Bo; Zeng, Zhi Jiang; Huang, Zachary Y.

    2012-01-01

    Background All honey bee species (Apis spp) share the same sex determination mechanism using the complementary sex determination (csd) gene. Only individuals heterogeneous at the csd allele develop into females, and the homozygous develop into diploid males, which do not survive. The honeybees are therefore under selection pressure to generate new csd alleles. Previous studies have shown that the csd gene is under balancing selection. We hypothesize that due to the long separation from the mainland of Hainan Island, China, that the giant honey bees (Apis dorsata) should show a founder effect for the csd gene, with many different alleles clustered together, and these would be absent on the mainland. Methodology/Principal Findings We sampled A. dorsata workers from both Hainan and Guangxi Provinces and then cloned and sequenced region 3 of the csd gene and constructed phylogenetic trees. We failed to find any clustering of the csd alleles according to their geographical origin, i.e. the Hainan and Guangxi samples did not form separate clades. Further analysis by including previously published csd sequences also failed to show any clade-forming in both the Philippines and Malaysia. Conclusions/Significance Results from this study and those from previous studies did not support the expectations of a founder effect. We conclude that because of the extremely high mating frequency of A. dorsata queens, a founder effect does not apply in this species. PMID:22511940

  1. The sex-peptide gene (Acp70A) is duplicated in Drosophila subobscura.

    PubMed

    Cirera, S; Aguadé, M

    1998-04-14

    A 3.1-kb region of Drosphila subobscura homologous to the Acp70A region of D. melanogaster, which contains the sex-peptide gene, was cloned and sequenced. This region contains an approximately 600-bp duplication that includes the sex-peptide and its 5' and 3' flanking regions. The preproteins are 54 and 56 amino acids long, respectively (as compared to 55 amino acids in D. melanogaster), and each includes a 19-amino-acid-long signal peptide. The C-terminal part of the mature peptide is highly conserved between D. melanogaster and the two copies of D. subobscura. In this species, both copies of the gene are transcribed and, like in D. melangaster, only expressed in males. The duplicated region includes 300 bp upstream of the gene that would therefore seem sufficient for their expression in males. This region presents at its 5' end a stretch 93-bp that has a high similarity with the corresponding region of D. melanogaster and could be part of a still unidentified regulatory element of these genes.

  2. Rainfall-driven sex-ratio genes in African buffalo suggested by correlations between Y-chromosomal haplotype frequencies and foetal sex ratio

    PubMed Central

    2010-01-01

    Background The Y-chromosomal diversity in the African buffalo (Syncerus caffer) population of Kruger National Park (KNP) is characterized by rainfall-driven haplotype frequency shifts between year cohorts. Stable Y-chromosomal polymorphism is difficult to reconcile with haplotype frequency variations without assuming frequency-dependent selection or specific interactions in the population dynamics of X- and Y-chromosomal genes, since otherwise the fittest haplotype would inevitably sweep to fixation. Stable Y-chromosomal polymorphism due one of these factors only seems possible when there are Y-chromosomal distorters of an equal sex ratio, which act by negatively affecting X-gametes, or Y-chromosomal suppressors of a female-biased sex ratio. These sex-ratio (SR) genes modify (suppress) gamete transmission in their own favour at a fitness cost, allowing for stable polymorphism. Results Here we show temporal correlations between Y-chromosomal haplotype frequencies and foetal sex ratios in the KNP buffalo population, suggesting SR genes. Frequencies varied by a factor of five; too high to be alternatively explained by Y-chromosomal effects on pregnancy loss. Sex ratios were male-biased during wet and female-biased during dry periods (male proportion: 0.47-0.53), seasonally and annually. Both wet and dry periods were associated with a specific haplotype indicating a SR distorter and SR suppressor, respectively. Conclusions The distinctive properties suggested for explaining Y-chromosomal polymorphism in African buffalo may not be restricted to this species alone. SR genes may play a broader and largely overlooked role in mammalian sex-ratio variation. PMID:20416038

  3. Rainfall-driven sex-ratio genes in African buffalo suggested by correlations between Y-chromosomal haplotype frequencies and foetal sex ratio.

    PubMed

    van Hooft, Pim; Prins, Herbert H T; Getz, Wayne M; Jolles, Anna E; van Wieren, Sipke E; Greyling, Barend J; van Helden, Paul D; Bastos, Armanda D S

    2010-04-23

    The Y-chromosomal diversity in the African buffalo (Syncerus caffer) population of Kruger National Park (KNP) is characterized by rainfall-driven haplotype frequency shifts between year cohorts. Stable Y-chromosomal polymorphism is difficult to reconcile with haplotype frequency variations without assuming frequency-dependent selection or specific interactions in the population dynamics of X- and Y-chromosomal genes, since otherwise the fittest haplotype would inevitably sweep to fixation. Stable Y-chromosomal polymorphism due one of these factors only seems possible when there are Y-chromosomal distorters of an equal sex ratio, which act by negatively affecting X-gametes, or Y-chromosomal suppressors of a female-biased sex ratio. These sex-ratio (SR) genes modify (suppress) gamete transmission in their own favour at a fitness cost, allowing for stable polymorphism. Here we show temporal correlations between Y-chromosomal haplotype frequencies and foetal sex ratios in the KNP buffalo population, suggesting SR genes. Frequencies varied by a factor of five; too high to be alternatively explained by Y-chromosomal effects on pregnancy loss. Sex ratios were male-biased during wet and female-biased during dry periods (male proportion: 0.47-0.53), seasonally and annually. Both wet and dry periods were associated with a specific haplotype indicating a SR distorter and SR suppressor, respectively. The distinctive properties suggested for explaining Y-chromosomal polymorphism in African buffalo may not be restricted to this species alone. SR genes may play a broader and largely overlooked role in mammalian sex-ratio variation.

  4. Male sex interspecies divergence and down regulation of expression of spermatogenesis genes in Drosophila sterile hybrids.

    PubMed

    Sundararajan, Vignesh; Civetta, Alberto

    2011-01-01

    Male sex genes have shown a pattern of rapid interspecies divergence at both the coding and gene expression level. A common outcome from crosses between closely-related species is hybrid male sterility. Phenotypic and genetic studies in Drosophila sterile hybrid males have shown that spermatogenesis arrest is postmeiotic with few exceptions, and that most misregulated genes are involved in late stages of spermatogenesis. Comparative studies of gene regulation in sterile hybrids and parental species have mainly used microarrays providing a whole genome representation of regulatory problems in sterile hybrids. Real-time PCR studies can reject or reveal differences not observed in microarray assays. Moreover, differences in gene expression between samples can be dependant on the source of RNA (e.g., whole body vs. tissue). Here we survey expression in D. simulans, D. mauritiana and both intra and interspecies hybrids using a real-time PCR approach for eight genes expressed at the four main stages of sperm development. We find that all genes show a trend toward under expression in the testes of sterile hybrids relative to parental species with only the two proliferation genes (bam and bgcn) and the two meiotic class genes (can and sa) showing significant down regulation. The observed pattern of down regulation for the genes tested can not fully explain hybrid male sterility. We discuss the down regulation of spermatogenesis genes in hybrids between closely-related species within the contest of rapid divergence experienced by the male genome, hybrid sterility and possible allometric changes due to subtle testes-specific developmental abnormalities.

  5. Transcriptional regulation of the Sex-lethal gene by helix-loop-helix proteins.

    PubMed

    Hoshijima, K; Kohyama, A; Watakabe, I; Inoue, K; Sakamoto, H; Shimura, Y

    1995-09-11

    Somatic sex determination in Drosophila depends on the expression of Sex-lethal (Sxl), whose level is determined by the relative number of X chromosomes and sets of autosomes (X:A ratio). The first step in regulation of Sxl expression is transcriptional control from its early promoter and several genes encoding transcription factors of the helix-loop-helix (HLH) family such as daughterless (da), sisterless-b (sis-b), deadpan (dpn) and extramacrochaetae (emc) have been implicated. By the use of transfection assays and in vitro binding experiments, here we show that da/sis-b heterodimers bind several sites on the Sxl early promoter with different affinities and consequently tune the level of active transcription from this promoter. Interestingly, our data indicate that repression by the dpn product of da/sis-b dependent activation results from specific binding of dpn protein to a unique site within the promoter. This contrasts with the mode of emc repression, which inhibits the formation of the da/sis-b heterodimers. These results reveal the molecular mechanisms by which Sxl gene transcription is positively or negatively regulated to control somatic sex determination.

  6. Estimating the Sex-Specific Effects of Genes on Facial Attractiveness and Sexual Dimorphism

    PubMed Central

    Purkey, Alicia M.; Grebe, Nicholas M.; Carey, Gregory; Garver-Apgar, Christine E.; Bates, Timothy C.; Arden, Rosalind; Hewitt, John K.; Medland, Sarah E.; Martin, Nicholas G.; Zietsch, Brendan P.; Keller, Matthew C.

    2014-01-01

    Human facial attractiveness and facial sexual dimorphism (masculinity–femininity) are important facets of mate choice and are hypothesized to honestly advertise genetic quality. However, it is unclear whether genes influencing facial attractiveness and masculinity–femininity have similar, opposing, or independent effects across sex, and the heritability of these phenotypes is poorly characterized. To investigate these issues, we assessed facial attractiveness and facial masculinity–femininity in the largest genetically informative sample (n = 1,580 same- and opposite-sex twin pairs and siblings) to assess these questions to date. The heritability was ~0.50–0.70 for attractiveness and ~0.40–0.50 for facial masculinity– femininity, indicating that, despite ostensible selection on genes influencing these traits, substantial genetic variation persists in both. Importantly, we found evidence for intralocus sexual conflict, whereby alleles that increase masculinity in males have the same effect in females. Additionally, genetic influences on attractiveness were shared across the sexes, suggesting that attractive fathers tend to have attractive daughters and attractive mothers tend to have attractive sons. PMID:24213680

  7. Estimating the sex-specific effects of genes on facial attractiveness and sexual dimorphism.

    PubMed

    Mitchem, Dorian G; Purkey, Alicia M; Grebe, Nicholas M; Carey, Gregory; Garver-Apgar, Christine E; Bates, Timothy C; Arden, Rosalind; Hewitt, John K; Medland, Sarah E; Martin, Nicholas G; Zietsch, Brendan P; Keller, Matthew C

    2014-05-01

    Human facial attractiveness and facial sexual dimorphism (masculinity-femininity) are important facets of mate choice and are hypothesized to honestly advertise genetic quality. However, it is unclear whether genes influencing facial attractiveness and masculinity-femininity have similar, opposing, or independent effects across sex, and the heritability of these phenotypes is poorly characterized. To investigate these issues, we assessed facial attractiveness and facial masculinity-femininity in the largest genetically informative sample (n = 1,580 same- and opposite-sex twin pairs and siblings) to assess these questions to date. The heritability was ~0.50-0.70 for attractiveness and ~0.40-0.50 for facial masculinity-femininity, indicating that, despite ostensible selection on genes influencing these traits, substantial genetic variation persists in both. Importantly, we found evidence for intralocus sexual conflict, whereby alleles that increase masculinity in males have the same effect in females. Additionally, genetic influences on attractiveness were shared across the sexes, suggesting that attractive fathers tend to have attractive daughters and attractive mothers tend to have attractive sons.

  8. Geographic variability in expression of the sex-linked AAT-1 gene of the bell-ring frog, Buergeria buergeri.

    PubMed

    Sumida, Masayuki; Ohta, Shigeru; Atsumi, Shigeru; Fujii, Tamotsu

    2004-03-15

    Cytological observation and artificial crossing experiments were used to examine the geographic differences in the sex-determining mechanism and mode of inheritance of the sex-linked AAT-1 gene in the bell-ring frog, Buergeria buergeri. The AAT-1 phenotypes were also examined by allozyme analysis using field-caught females and males collected from 19 populations from the Honshu, Shikoku, and Kyushu islands of Japan, in order to comprehensively elucidate the geographic variability in the expression of the sex-linked AAT-1 gene of B. buergeri. The results showed that the Aomori population of B. buergeri from the northern end of Honshu was female heterogametic in sex determination, that chromosome No. VII was a sex chromosome of the ZZ/ZW type, and that the sex-linked AAT-1 gene was expressed on both the Z and W chromosomes. This mode of AAT-1 expression in the Aomori population was different from that in the Hiroshima population from western Honshu, in which the AAT-1 gene was expressed on the Z chromosome but not on the W chromosome. The results also showed that there was no differentiation among populations in the expression of the AAT-1 genes on the Z chromosome, whereas two populations, the Hiroshima and Aomori frogs, exhibited distinct modes of expression of the AAT-1 gene on the W chromosome. These two modes of expression may be widely distributed in western and eastern Japan, and coexist in the central part of Honshu.

  9. Functional analysis of sex-determination genes by gene silencing with LNA-DNA gapmers in the silkworm, Bombyx mori.

    PubMed

    Sakai, Hiroki; Sakaguchi, Honami; Aoki, Fugaku; Suzuki, Masataka G

    2015-08-01

    The sexual fate of B. mori is determined genetically; ZW, female and ZZ, male. Recently, we successfully identified a strong candidate gene at the top of the sex determination cascade in B. mori. This gene was termed Feminizer (Fem) and revealed to be a source of Fem-piRNA. Further, we found that B. mori doublesex (Bmdsx) splicing was markedly altered to produce the male-type isoform when a Fem-piRNA inhibitor was injected into ZW embryos. Moreover, knockdown of Masculinizer (Masc), a Fem-piRNA target gene, altered to produce the female-type isoform of Bmdsx in male embryos. However, it remains unclear as to whether Masc directly regulates the sex-specific expression of Bmdsx. In previous studies, we determined that the male-specific isoform of the Bombyx homolog of IGF-II mRNA-binding protein (Imp(M)) was involved in the male-specific splicing of Bmdsx. In an attempt to clarify the genetic relationship between Fem, Masc, Imp(M), and Bmdsx, knockdown experiments were performed. Knockdown of Fem shifted into male-type Bmdsx, Imp(M) and Masc in female embryos. Knockdown of Masc led to the production of the female-type Bmdsx and a dramatic reduction in Imp(M) expression in male embryos. Knockdown of Imp(M) shifted Bmdsx splice mode from the male-type into the female-type. Our results suggest that: (1) Fem reduces Masc expression, (2) Masc dramatically induces Imp(M) expression, and (3) Imp(M) shifting Bmdsx splice mode from the female-type into the male-type. Based on these findings, we propose a possible genetic cascade regulating sex determination in B. mori.

  10. Influence of genes, sex, age and environment on the onset of autoimmune hepatitis.

    PubMed

    Béland, Kathie; Lapierre, Pascal; Alvarez, Fernando

    2009-03-07

    The pathogenesis of autoimmune hepatitis (AIH) is complex. However, it is believed that a susceptible individual, owing to his genetic background, sex and age, can develop the disease following exposure to an environmental trigger. Autoimmune hepatitis does not follow a Mendelian pattern of inheritance; hence no single causative genetic locus has been identified. However, several genes, inside and outside the HLA locus, have been linked to an increased susceptibility to AIH. Epidemiological evidence also suggests that the sex and age of the patient plays a role in AIH pathogenesis as the disease onset occurs mainly in the two first decades of life and a higher disease incidence is observed in females. No environmental trigger has been identified, but several have been proposed, mainly viruses and xenobiotics. This article aims at reviewing the current knowledge on susceptibility factors leading to AIH and putative triggers, emphasizing fundamental mechanisms responsible for the break of liver immunological tolerance.

  11. Down regulation of gene related sex hormone synthesis pathway in mouse testes by miroestrol and deoxymiroestrol.

    PubMed

    Udomsuk, Latiporn; Juengwatanatrakul, Thaweesak; Putalun, Waraporn; Jarukamjorn, Kanokwan

    2011-12-01

    Miroestrol and deoxymiroestrol are phytoestrogens isolated from tuberous root of Pueraria candollei var. mirifica. Modulatory effects of miroestrol and deoxymiroestrol on enzymes involved in sex-hormone synthesis pathway in male C57BL/6 mice were investigated using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). Miroestrol and deoxymiroestrol suppressed the expressions of 3β-HSD, 17β-HSD1, and CYP17 while CYP19 mRNA expression was slightly decreased. In addition, the expression of 17β-HSD2 was induced in correlation with those did by estradiol. These observations supported that miroestrol and deoxymiroestrol could exhibit the same effect as estradiol regarding regulation of testicular gene related sex hormone synthesis pathway.

  12. Control of mosquito-borne infectious diseases: Sex and gene drive

    PubMed Central

    Adelman, Zach N.; Tu, Zhijian

    2015-01-01

    Sterile male releases have successfully reduced local populations of the dengue vector, Aedes aegypti, but challenges remain in scale and in separating sexes prior to release. The recent discovery of the first mosquito male determining factor (M factor), will facilitate our understanding of the genetic programs that initiate sexual development in mosquitoes. Manipulation of the M-factor and possible intermediary factors may result in female-to-male conversion or female killing, enabling efficient sex-separation and effective reduction of target mosquito populations. Given recent breakthroughs in the development of CRISPR-Cas9 reagents as a source of gene drive, more advanced technologies at driving maleness, the ultimate disease refractory phenotype, become possible and may represent efficient and self-limiting methods to control mosquito populations. PMID:26897660

  13. MYB transcription factor gene involved in sex determination in Asparagus officinalis.

    PubMed

    Murase, Kohji; Shigenobu, Shuji; Fujii, Sota; Ueda, Kazuki; Murata, Takanori; Sakamoto, Ai; Wada, Yuko; Yamaguchi, Katsushi; Osakabe, Yuriko; Osakabe, Keishi; Kanno, Akira; Ozaki, Yukio; Takayama, Seiji

    2017-01-01

    Dioecy is a plant mating system in which individuals of a species are either male or female. Although many flowering plants evolved independently from hermaphroditism to dioecy, the molecular mechanism underlying this transition remains largely unknown. Sex determination in the dioecious plant Asparagus officinalis is controlled by X and Y chromosomes; the male and female karyotypes are XY and XX, respectively. Transcriptome analysis of A. officinalis buds showed that a MYB-like gene, Male Specific Expression 1 (MSE1), is specifically expressed in males. MSE1 exhibits tight linkage with the Y chromosome, specific expression in early anther development and loss of function on the X chromosome. Knockout of the MSE1 orthologue in Arabidopsis induces male sterility. Thus, MSE1 acts in sex determination in A. officinalis. © 2016 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

  14. Sex-based differences in myocardial gene expression in recently deceased organ donors with no prior cardiovascular disease.

    PubMed

    InanlooRahatloo, Kolsoum; Liang, Grace; Vo, Davis; Ebert, Antje; Nguyen, Ivy; Nguyen, Patricia K

    2017-01-01

    Sex differences in the development of the normal heart and the prevalence of cardiomyopathies have been reported. The molecular basis of these differences remains unclear. Sex differences in the human heart might be related to patterns of gene expression. Recent studies have shown that sex specific differences in gene expression in tissues including the brain, kidney, skeletal muscle, and liver. Similar data is limited for the heart. Herein we address this issue by analyzing donor and post-mortem adult human heart samples originating from 46 control individuals to study whole-genome gene expression in the human left ventricle. Using data from the genotype tissue expression (GTEx) project, we compared the transcriptome expression profiles of male and female hearts. We found that genes located on sex chromosomes were the most abundant ones among the sexually dimorphic genes. The majority of differentially expressed autosomal genes were those involved in the regulation of inflammation, which has been found to be an important contributor to left ventricular remodeling. Specifically, genes on autosomal chromosomes encoding chemokines with inflammatory functions (e.g. CCL4, CX3CL1, TNFAIP3) and a gene that regulates adhesion of immune cells to the endothelium (e.g., VCAM1) were identified with sex-specific expression levels. This study underlines the relevance of sex as an important modifier of cardiac gene expression. These results have important implications in the understanding of the differences in the physiology of the male and female heart transcriptome and how they may lead to different sex specific difference in human cardiac health and its control.

  15. Structure and function of ribosomal protein S4 genes on the human and mouse sex chromosomes.

    PubMed

    Zinn, A R; Alagappan, R K; Brown, L G; Wool, I; Page, D C

    1994-04-01

    The human sex-linked genes RPS4X and RPS4Y encode distinct isoforms of ribosomal protein S4. Insufficient expression of S4 may play a role in the development of Turner syndrome, the complex human phenotype associated with monosomy X. In mice, the S4 protein is encoded by an X-linked gene, Rps4, and is identical to human S4X; there is no mouse Y homolog. We report here the organization of the human RPS4X and RPS4Y and mouse Rps4 genes. Each gene comprises seven exons; the positions of introns are conserved. The 5' flanking sequences of human RPS4X and mouse Rps4 are very similar, while RPS4Y diverges shortly upstream of the transcription start site. In chickens, S4 is encoded by a single gene that is not sex linked. The chicken protein differs from human S4X by four amino acid substitutions, all within a region encoded by a single exon. Three of the four substitutions are also present in human S4Y, suggesting that the chicken S4 gene may have arisen by recombination between S4X- and S4Y-like sequences. Using isoform-specific antisera, we determined that human S4X and S4Y are both present in translationally active ribosomes. S4Y is about 10 to 15% as abundant as S4X in ribosomes from normal male placental tissue and 46,XY cultured cells. In 49,XYYYY cells, S4Y is about half as abundant as S4X. In 49,XXXXY cells, S4Y is barely detectable. These results bear on the hypothesized role of S4 deficiency in Turner syndrome.

  16. Maternal Diets Trigger Sex-Specific Divergent Trajectories of Gene Expression and Epigenetic Systems in Mouse Placenta

    PubMed Central

    Gabory, Anne; Ferry, Laure; Fajardy, Isabelle; Jouneau, Luc; Gothié, Jean-David; Vigé, Alexandre; Fleur, Cécile; Mayeur, Sylvain; Gallou-Kabani, Catherine; Gross, Marie-Sylvie; Attig, Linda; Vambergue, Anne; Lesage, Jean; Reusens, Brigitte; Vieau, Didier; Remacle, Claude; Jais, Jean-Philippe; Junien, Claudine

    2012-01-01

    Males and females responses to gestational overnutrition set the stage for subsequent sex-specific differences in adult onset non communicable diseases. Placenta, as a widely recognized programming agent, contibutes to the underlying processes. According to our previous findings, a high-fat diet during gestation triggers sex-specific epigenetic alterations within CpG and throughout the genome, together with the deregulation of clusters of imprinted genes. We further investigated the impact of diet and sex on placental histology, transcriptomic and epigenetic signatures in mice. Both basal gene expression and response to maternal high-fat diet were sexually dimorphic in whole placentas. Numerous genes showed sexually dimorphic expression, but only 11 genes regardless of the diet. In line with the key role of genes belonging to the sex chromosomes, 3 of these genes were Y-specific and 3 were X-specific. Amongst all the genes that were differentially expressed under a high-fat diet, only 16 genes were consistently affected in both males and females. The differences were not only quantitative but remarkably qualitative. The biological functions and networks of genes dysregulated differed markedly between the sexes. Seven genes of the epigenetic machinery were dysregulated, due to effects of diet, sex or both, including the Y- and X-linked histone demethylase paralogues Kdm5c and Kdm5d, which could mark differently male and female epigenomes. The DNA methyltransferase cofactor Dnmt3l gene expression was affected, reminiscent of our previous observation of changes in global DNA methylation. Overall, this striking sexual dimorphism of programming trajectories impose a considerable revision of the current dietary interventions protocols. PMID:23144842

  17. Maternal diets trigger sex-specific divergent trajectories of gene expression and epigenetic systems in mouse placenta.

    PubMed

    Gabory, Anne; Ferry, Laure; Fajardy, Isabelle; Jouneau, Luc; Gothié, Jean-David; Vigé, Alexandre; Fleur, Cécile; Mayeur, Sylvain; Gallou-Kabani, Catherine; Gross, Marie-Sylvie; Attig, Linda; Vambergue, Anne; Lesage, Jean; Reusens, Brigitte; Vieau, Didier; Remacle, Claude; Jais, Jean-Philippe; Junien, Claudine

    2012-01-01

    Males and females responses to gestational overnutrition set the stage for subsequent sex-specific differences in adult onset non communicable diseases. Placenta, as a widely recognized programming agent, contibutes to the underlying processes. According to our previous findings, a high-fat diet during gestation triggers sex-specific epigenetic alterations within CpG and throughout the genome, together with the deregulation of clusters of imprinted genes. We further investigated the impact of diet and sex on placental histology, transcriptomic and epigenetic signatures in mice. Both basal gene expression and response to maternal high-fat diet were sexually dimorphic in whole placentas. Numerous genes showed sexually dimorphic expression, but only 11 genes regardless of the diet. In line with the key role of genes belonging to the sex chromosomes, 3 of these genes were Y-specific and 3 were X-specific. Amongst all the genes that were differentially expressed under a high-fat diet, only 16 genes were consistently affected in both males and females. The differences were not only quantitative but remarkably qualitative. The biological functions and networks of genes dysregulated differed markedly between the sexes. Seven genes of the epigenetic machinery were dysregulated, due to effects of diet, sex or both, including the Y- and X-linked histone demethylase paralogues Kdm5c and Kdm5d, which could mark differently male and female epigenomes. The DNA methyltransferase cofactor Dnmt3l gene expression was affected, reminiscent of our previous observation of changes in global DNA methylation. Overall, this striking sexual dimorphism of programming trajectories impose a considerable revision of the current dietary interventions protocols.

  18. Identification and characterization of a Masculinizer (Masc) gene involved in sex differentiation in Artemia.

    PubMed

    Li, Dong-Rui; Ye, Hui-Li; Yang, Jin-Shu; Y