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Sample records for abnormal chromosome segregation

  1. Latrunculin A treatment prevents abnormal chromosome segregation for successful development of cloned embryos.

    PubMed

    Terashita, Yukari; Yamagata, Kazuo; Tokoro, Mikiko; Itoi, Fumiaki; Wakayama, Sayaka; Li, Chong; Sato, Eimei; Tanemura, Kentaro; Wakayama, Teruhiko

    2013-01-01

    Somatic cell nuclear transfer to an enucleated oocyte is used for reprogramming somatic cells with the aim of achieving totipotency, but most cloned embryos die in the uterus after transfer. While modifying epigenetic states of cloned embryos can improve their development, the production rate of cloned embryos can also be enhanced by changing other factors. It has already been shown that abnormal chromosome segregation (ACS) is a major cause of the developmental failure of cloned embryos and that Latrunculin A (LatA), an actin polymerization inhibitor, improves F-actin formation and birth rate of cloned embryos. Since F-actin is important for chromosome congression in embryos, here we examined the relation between ACS and F-actin in cloned embryos. Using LatA treatment, the occurrence of ACS decreased significantly whereas cloned embryo-specific epigenetic abnormalities such as dimethylation of histone H3 at lysine 9 (H3K9me2) could not be corrected. In contrast, when H3K9me2 was normalized using the G9a histone methyltransferase inhibitor BIX-01294, the Magea2 gene-essential for normal development but never before expressed in cloned embryos-was expressed. However, this did not increase the cloning success rate. Thus, non-epigenetic factors also play an important role in determining the efficiency of mouse cloning.

  2. Latrunculin A Treatment Prevents Abnormal Chromosome Segregation for Successful Development of Cloned Embryos

    PubMed Central

    Terashita, Yukari; Yamagata, Kazuo; Tokoro, Mikiko; Itoi, Fumiaki; Wakayama, Sayaka; Li, Chong; Sato, Eimei; Tanemura, Kentaro; Wakayama, Teruhiko

    2013-01-01

    Somatic cell nuclear transfer to an enucleated oocyte is used for reprogramming somatic cells with the aim of achieving totipotency, but most cloned embryos die in the uterus after transfer. While modifying epigenetic states of cloned embryos can improve their development, the production rate of cloned embryos can also be enhanced by changing other factors. It has already been shown that abnormal chromosome segregation (ACS) is a major cause of the developmental failure of cloned embryos and that Latrunculin A (LatA), an actin polymerization inhibitor, improves F-actin formation and birth rate of cloned embryos. Since F-actin is important for chromosome congression in embryos, here we examined the relation between ACS and F-actin in cloned embryos. Using LatA treatment, the occurrence of ACS decreased significantly whereas cloned embryo-specific epigenetic abnormalities such as dimethylation of histone H3 at lysine 9 (H3K9me2) could not be corrected. In contrast, when H3K9me2 was normalized using the G9a histone methyltransferase inhibitor BIX-01294, the Magea2 gene—essential for normal development but never before expressed in cloned embryos—was expressed. However, this did not increase the cloning success rate. Thus, non-epigenetic factors also play an important role in determining the efficiency of mouse cloning. PMID:24205216

  3. Chromosome Abnormalities

    MedlinePlus

    ... chromosome has attached to another at the centromere. Inversions: A portion of the chromosome has broken off, ... individual and was not inherited from the parents. Inversion: A portion of the chromosome has broken off, ...

  4. Bacterial chromosome organization and segregation

    PubMed Central

    Badrinarayanan, Anjana; Le, Tung BK; Laub, Michael T

    2016-01-01

    If fully stretched out, a typical bacterial chromosome would be nearly one millimeter long, or approximately 1000 times the length of a cell. Not only must cells massively compact their genetic material, but they must also organize their DNA in a manner that is compatible with a range of cellular processes, including DNA replication, DNA repair, homologous recombination, and horizontal gene transfer. Recent work, driven in part by technological advances, has begun to reveal the general principles of chromosome organization in bacteria. Here, drawing on studies of many different organisms, we review the emerging picture of how bacterial chromosomes are structured at multiple length-scales, highlighting the functions of various DNA-binding proteins and impact of physical forces. Additionally, we discuss the spatial dynamics of chromosomes, particularly during their segregation to daughter cells. Although there has been tremendous progress, we also highlight gaps that remain in understanding chromosome organization and segregation. PMID:26566111

  5. A sexy spin on nonrandom chromosome segregation.

    PubMed

    Charville, Gregory W; Rando, Thomas A

    2013-06-06

    Nonrandom chromosome segregation is an intriguing phenomenon linked to certain asymmetric stem cell divisions. In a recent report in Nature, Yadlapalli and Yamashita (2013) observe nonrandom segregation of X and Y chromosomes in Drosophila germline stem cells and shed light on the complex mechanisms of this fascinating process. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Chromosomal abnormalities in human sperm

    SciTech Connect

    Martin, R.H.

    1985-01-01

    The ability to analyze human sperm chromosome complements after penetration of zona pellucida-free hamster eggs provides the first opportunity to study the frequency and type of chromosomal abnormalities in human gametes. Two large-scale studies have provided information on normal men. We have studied 1,426 sperm complements from 45 normal men and found an abnormality rate of 8.9%. Brandriff et al. (5) found 8.1% abnormal complements in 909 sperm from 4 men. The distribution of numerical and structural abnormalities was markedly dissimilar in the 2 studies. The frequency of aneuploidy was 5% in our sample and only 1.6% in Brandriff's, perhapsmore » reflecting individual variability among donors. The frequency of 24,YY sperm was low: 0/1,426 and 1/909. This suggests that the estimates of nondisjunction based on fluorescent Y body data (1% to 5%) are not accurate. We have also studied men at increased risk of sperm chromosomal abnormalities. The frequency of chromosomally unbalanced sperm in 6 men heterozygous for structural abnormalities varied dramatically: 77% for t11;22, 32% for t6;14, 19% for t5;18, 13% for t14;21, and 0% for inv 3 and 7. We have also studied 13 cancer patients before and after radiotherapy and demonstrated a significant dose-dependent increase of sperm chromosome abnormalities (numerical and structural) 36 months after radiation treatment.« less

  7. Chromosome Segregation Is Biased by Kinetochore Size.

    PubMed

    Drpic, Danica; Almeida, Ana C; Aguiar, Paulo; Renda, Fioranna; Damas, Joana; Lewin, Harris A; Larkin, Denis M; Khodjakov, Alexey; Maiato, Helder

    2018-05-07

    Chromosome missegregation during mitosis or meiosis is a hallmark of cancer and the main cause of prenatal death in humans. The gain or loss of specific chromosomes is thought to be random, with cell viability being essentially determined by selection. Several established pathways including centrosome amplification, sister-chromatid cohesion defects, or a compromised spindle assembly checkpoint can lead to chromosome missegregation. However, how specific intrinsic features of the kinetochore-the critical chromosomal interface with spindle microtubules-impact chromosome segregation remains poorly understood. Here we used the unique cytological attributes of female Indian muntjac, the mammal with the lowest known chromosome number (2n = 6), to characterize and track individual chromosomes with distinct kinetochore size throughout mitosis. We show that centromere and kinetochore functional layers scale proportionally with centromere size. Measurement of intra-kinetochore distances, serial-section electron microscopy, and RNAi against key kinetochore proteins confirmed a standard structural and functional organization of the Indian muntjac kinetochores and revealed that microtubule binding capacity scales with kinetochore size. Surprisingly, we found that chromosome segregation in this species is not random. Chromosomes with larger kinetochores bi-oriented more efficiently and showed a 2-fold bias to congress to the equator in a motor-independent manner. Despite robust correction mechanisms during unperturbed mitosis, chromosomes with larger kinetochores were also strongly biased to establish erroneous merotelic attachments and missegregate during anaphase. This bias was impervious to the experimental attenuation of polar ejection forces on chromosome arms by RNAi against the chromokinesin Kif4a. Thus, kinetochore size is an important determinant of chromosome segregation fidelity. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  8. CENP-A regulates chromosome segregation during the first meiosis of mouse oocytes.

    PubMed

    Li, Li; Qi, Shu-Tao; Sun, Qing-Yuan; Chen, Shi-Ling

    2017-06-01

    Proper chromosome separation in both mitosis and meiosis depends on the correct connection between kinetochores of chromosomes and spindle microtubules. Kinetochore dysfunction can lead to unequal distribution of chromosomes during cell division and result in aneuploidy, thus kinetochores are critical for faithful segregation of chromosomes. Centromere protein A (CENP-A) is an important component of the inner kinetochore plate. Multiple studies in mitosis have found that deficiencies in CENP-A could result in structural and functional changes of kinetochores, leading to abnormal chromosome segregation, aneuploidy and apoptosis in cells. Here we report the expression and function of CENP-A during mouse oocyte meiosis. Our study found that microinjection of CENP-A blocking antibody resulted in errors of homologous chromosome segregation and caused aneuploidy in eggs. Thus, our findings provide evidence that CENP-A is critical for the faithful chromosome segregation during mammalian oocyte meiosis.

  9. Numerically abnormal chromosome constitutions in humans

    SciTech Connect

    NONE

    1993-12-31

    Chapter 24, discusses numerically abnormal chromosome constitutions in humans. This involves abnormalities of human chromosome number, including polyploidy (when the number of sets of chromosomes increases) and aneuploidy (when the number of individual normal chromosomes changes). Chapter sections discuss the following chromosomal abnormalities: human triploids, imprinting and uniparental disomy, human tetraploids, hydatidiform moles, anomalies caused by chromosomal imbalance, 13 trisomy (D{sub 1} trisomy, Patau syndrome), 21 trisomy (Down syndrome), 18 trisomy syndrome (Edwards syndrome), other autosomal aneuploidy syndromes, and spontaneous abortions. The chapter concludes with remarks on the nonrandom participation of chromosomes in trisomy. 69 refs., 3 figs., 4 tabs.

  10. TMAP/CKAP2 is essential for proper chromosome segregation.

    PubMed

    Hong, Kyung Uk; Kim, Eunhee; Bae, Chang-Dae; Park, Joobae

    2009-01-15

    Tumor-associated microtubule-associated protein (TMAP), also known as cytoskeleton associated protein 2 (CKAP2), is a novel mitotic spindle-associated protein which is frequently up-regulated in various malignances. However, its cellular functions remain unknown. Previous reports suggested that the cellular functions of TMAP/CKAP2 pertain to regulation of the dynamics and assembly of the mitotic spindle. To investigate its role in mitosis, we studied the effects of siRNA-mediated depletion of TMAP/CKAP2 in cultured mammalian cells. Unexpectedly, TMAP/CKAP2 knockdown did not result in significant alterations of the spindle apparatus. However, TMAP/CKAP2-depleted cells often exhibited abnormal nuclear morphologies, which were accompanied by abnormal organization of the nuclear lamina, and chromatin bridge formation between two daughter cell nuclei. Time lapse video microscopy revealed that the changes in nuclear morphology and chromatin bridge formations observed in TMAP/CKAP2-depleted cells are the result of defects in chromosome segregation. Consistent with this, the spindle checkpoint activity was significantly reduced in TMAP/CKAP2-depleted cells. Moreover, chromosome missegregation induced by depletion of TMAP/CKAP2 ultimately resulted in reduced cell viability and increased chromosomal instability. Our present findings demonstrate that TMAP/CKAP2 is essential for proper chromosome segregation and for maintaining genomic stability.

  11. Dandy-Walker syndrome and chromosomal abnormalities.

    PubMed

    Imataka, George; Yamanouchi, Hideo; Arisaka, Osamu

    2007-12-01

    Dandy-Walker syndrome (DWS) is a brain malformation of unknown etiology, but several reports have been published indicating that there is a causal relationship to various types of chromosomal abnormalities and malformation syndromes. In the present article, we present a bibliographical survey of several previously issued reports on chromosomal abnormalities associated with DWS, including our case of DWS found in trisomy 18. There are various types of chromosomal abnormalities associated with DWS; most of them are reported in chromosome 3, 9, 13 and 18. We also summarize some other chromosomal abnormalities and various congenital malformation syndromes.

  12. Sex chromosome abnormalities and psychiatric diseases

    PubMed Central

    Zhang, Xinzhu; Yang, Jian; Li, Yuhong; Ma, Xin; Li, Rena

    2017-01-01

    Excesses of sex chromosome abnormalities in patients with psychiatric diseases have recently been observed. It remains unclear whether sex chromosome abnormalities are related to sex differences in some psychiatric diseases. While studies showed evidence of susceptibility loci over many sex chromosomal regions related to various mental diseases, others demonstrated that the sex chromosome aneuploidies may be the key to exploring the pathogenesis of psychiatric disease. In this review, we will outline the current evidence on the interaction of sex chromosome abnormalities with schizophrenia, autism, ADHD and mood disorders. PMID:27992373

  13. Non-random Mis-segregation of Human Chromosomes.

    PubMed

    Worrall, Joseph Thomas; Tamura, Naoka; Mazzagatti, Alice; Shaikh, Nadeem; van Lingen, Tineke; Bakker, Bjorn; Spierings, Diana Carolina Johanna; Vladimirou, Elina; Foijer, Floris; McClelland, Sarah Elizabeth

    2018-06-12

    A common assumption is that human chromosomes carry equal chances of mis-segregation during compromised cell division. Human chromosomes vary in multiple parameters that might generate bias, but technological limitations have precluded a comprehensive analysis of chromosome-specific aneuploidy. Here, by imaging specific centromeres coupled with high-throughput single-cell analysis as well as single-cell sequencing, we show that aneuploidy occurs non-randomly following common treatments to elevate chromosome mis-segregation. Temporary spindle disruption leads to elevated mis-segregation and aneuploidy of a subset of chromosomes, particularly affecting chromosomes 1 and 2. Unexpectedly, we find that a period of mitotic delay weakens centromeric cohesion and promotes chromosome mis-segregation and that chromosomes 1 and 2 are particularly prone to suffer cohesion fatigue. Our findings demonstrate that inherent properties of individual chromosomes can bias chromosome mis-segregation and aneuploidy rates, with implications for studies on aneuploidy in human disease. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

  14. Advances in understanding paternally transmitted Chromosomal Abnormalities

    SciTech Connect

    Marchetti, F; Sloter, E; Wyrobek, A J

    2001-03-01

    Multicolor FISH has been adapted for detecting the major types of chromosomal abnormalities in human sperm including aneuploidies for clinically-relevant chromosomes, chromosomal aberrations including breaks and rearrangements, and other numerical abnormalities. The various sperm FISH assays have been used to evaluate healthy men, men of advanced age, and men who have received mutagenic cancer therapy. The mouse has also been used as a model to investigate the mechanism of paternally transmitted genetic damage. Sperm FISH for the mouse has been used to detect chromosomally abnormal mouse sperm, while the PAINT/DAPI analysis of mouse zygotes has been used to evaluate themore » types of chromosomal defects that can be paternally transmitted to the embryo and their effects on embryonic development.« less

  15. Molecular mechanisms of homologous chromosome pairing and segregation in plants.

    PubMed

    Zhang, Jing; Zhang, Bing; Su, Handong; Birchler, James A; Han, Fangpu

    2014-03-20

    In most eukaryotic species, three basic steps of pairing, recombination and synapsis occur during prophase of meiosis I. Homologous chromosomal pairing and recombination are essential for accurate segregation of chromosomes. In contrast to the well-studied processes such as recombination and synapsis, many aspects of chromosome pairing are still obscure. Recent progress in several species indicates that the telomere bouquet formation can facilitate homologous chromosome pairing by bringing chromosome ends into close proximity, but the sole presence of telomere clustering is not sufficient for recognizing homologous pairs. On the other hand, accurate segregation of the genetic material from parent to offspring during meiosis is dependent on the segregation of homologs in the reductional meiotic division (MI) with sister kinetochores exhibiting mono-orientation from the same pole, and the segregation of sister chromatids during the equational meiotic division (MII) with kinetochores showing bi-orientation from the two poles. The underlying mechanism of orientation and segregation is still unclear. Here we focus on recent studies in plants and other species that provide insight into how chromosomes find their partners and mechanisms mediating chromosomal segregation. Copyright © 2013. Published by Elsevier Ltd.

  16. Chromosomal rearrangement segregating with adrenoleukodystrophy: associated changes in color vision.

    PubMed Central

    Alpern, M; Sack, G H; Krantz, D H; Jenness, J; Zhang, H; Moser, H W

    1993-01-01

    A patient from a large kindred with adrenoleukodystrophy showed profound disturbance of color ordering, color matching, increment thresholds, and luminosity. Except for color matching, his performance was similar to blue-cone "monochromacy," an X chromosome-linked recessive retinal dystrophy in which color vision is dichromatic, mediated by the visual pigments of rods and short-wave-sensitive cones. Color matching, however, indicated that an abnormal rudimentary visual pigment was also present. This may reflect the presence of a recombinant visual pigment protein or altered regulation of residual pigment genes, due to DNA changes--deletion of the long-wave pigment gene and reorganized sequences 5' to the pigment gene cluster--that segregate with the metabolic defect in this kindred. PMID:8415729

  17. Chromosome and cell wall segregation in Streptococcus faecium ATCC 9790

    SciTech Connect

    Higgins, M.L.; Glaser, D.; Dicker, D.T.

    1989-01-01

    Segregation was studied by measuring the positions of autoradiographic grain clusters in chains formed from single cells containing on average less than one radiolabeled chromosome strand. The degree to which chromosomal and cell wall material cosegregated was quantified by using the methods of S. Cooper and M. Weinberger, dividing the number of chains labeled at the middle. This analysis indicated that in contrast to chromosomal segregation in Escherichia coli and, in some studies, to that in gram-positive rods, chromosomal segregation in Streptococcus faecium was slightly nonrandom and did not vary with growth rate. Results were not significantly affected by strandmore » exchange. In contrast, labeled cell wall segregated predominantly nonrandomly.« less

  18. Shugoshins: Tension-Sensitive Pericentromeric Adaptors Safeguarding Chromosome Segregation

    PubMed Central

    2014-01-01

    The shugoshin/Mei-S332 family are proteins that associate with the chromosomal region surrounding the centromere (the pericentromere) and that play multiple and distinct roles in ensuring the accuracy of chromosome segregation during both mitosis and meiosis. The underlying role of shugoshins appears to be to serve as pericentromeric adaptor proteins that recruit several different effectors to this region of the chromosome to regulate processes critical for chromosome segregation. Crucially, shugoshins undergo changes in their localization in response to the tension that is exerted on sister chromosomes by the forces of the spindle that will pull them apart. This has led to the idea that shugoshins provide a platform for activities required at the pericentromere only when sister chromosomes lack tension. Conversely, disassembly of the shugoshin pericentromeric platform may provide a signal that sister chromosomes are under tension. Here the functions and regulation of these important tension-sensitive pericentromeric proteins are discussed. PMID:25452306

  19. Four families with immunodeficiency and chromosome abnormalities.

    PubMed Central

    Candy, D C; Hayward, A R; Hughes, D T; Layward, L; Soothill, J F

    1979-01-01

    Six children, with severe deficiency of some or all of the immunoglobulins and minor somatic abnormalities, had chromosomal abnormalities: (1) 45,XY,t(13q/18q), (2) 46,XY,21ps +, (3) two brothers 46,XY (inv. 7) (4) 45,X,t(11p/10p)/46X,iXq,t(11p/10p) and, (5) in addendum, 45,XX,-18;46,XX, r18. The chromosome abnormalities were detected in B- as well as T-lymphocytes (as evidenced by using both PHA- and PWM-stimulated cultures) in all probands, but one was mosaic in PHA culture, although all his PWM-stimulated cells were abnormal. Chromosomal variants were also detected in relatives of three and immunodeficiency in relatives of two. Images Fig. 1 Fig. 3 PMID:314782

  20. Kinetochore-independent chromosome segregation driven by lateral microtubule bundles

    PubMed Central

    Muscat, Christina C; Torre-Santiago, Keila M; Tran, Michael V; Powers, James A; Wignall, Sarah M

    2015-01-01

    During cell division, chromosomes attach to spindle microtubules at sites called kinetochores, and force generated at the kinetochore-microtubule interface is the main driver of chromosome movement. Surprisingly, kinetochores are not required for chromosome segregation on acentrosomal spindles in Caenorhabditis elegans oocytes, but the mechanism driving chromosomes apart in their absence is not understood. In this study, we show that lateral microtubule–chromosome associations established during prometaphase remain intact during anaphase to facilitate separation, defining a novel form of kinetochore-independent segregation. Chromosome dynamics during congression and segregation are controlled by opposing forces; plus-end directed forces are mediated by a protein complex that forms a ring around the chromosome center and dynein on chromosome arms provides a minus-end force. At anaphase onset, ring removal shifts the balance between these forces, triggering poleward movement along lateral microtubule bundles. This represents an elegant strategy for controlling chromosomal movements during cell division distinct from the canonical kinetochore-driven mechanism. DOI: http://dx.doi.org/10.7554/eLife.06462.001 PMID:26026148

  1. Chromosomal abnormalities in a psychiatric population

    SciTech Connect

    Lewis, K.E.; Lubetsky, M.J.; Wenger, S.L.

    Over a 3.5 year period of time, 345 patients hospitalized for psychiatric problems were evaluated cytogenetically. The patient population included 76% males and 94% children with a mean age of 12 years. The criteria for testing was an undiagnosed etiology for mental retardation and/or autism. Cytogenetic studies identified 11, or 3%, with abnormal karyotypes, including 4 fragile X positive individuals (2 males, 2 females), and 8 with chromosomal aneuploidy, rearrangements, or deletions. While individuals with chromosomal abnormalities do not demonstrate specific behavioral, psychiatric, or developmental problems relative to other psychiatric patients, our results demonstrate the need for an increased awarenessmore » to order chromosomal analysis and fragile X testing in those individuals who have combinations of behavioral/psychiatric, learning, communication, or cognitive disturbance. 5 refs., 1 fig., 2 tabs.« less

  2. XYY chromosome abnormality in sexual homicide perpetrators.

    PubMed

    Briken, Peer; Habermann, Niels; Berner, Wolfgang; Hill, Andreas

    2006-03-05

    In a retrospective investigation of the court reports about sexual homicide perpetrators chromosome analysis had been carried out in 13 of 166 (7.8%) men. Three men (1.8%) with XYY chromosome abnormality were found. This rate is much higher than that found in unselected samples of prisoners (0.7-0.9%) or in the general population (0.01%). The three men had shown prepubescent abnormalities, school problems, and had suffered from physical abuse. The chromosome analysis in all cases had been carried out in connection with the forensic psychiatric court report due to the sexual homicide. However, two men had earlier psychiatric referrals. All were diagnosed as sexual sadistic, showed a psychopathic syndrome or psychopathy according to the Psychopathy Checklist-Revised [Hare RD, 1991, The Hare Psychopathy Checklist-Revised, Toronto, Ontario, Canada: Multi-Health Systems]. Two were multiple murderers. Especially forensic psychiatrists should be vigilant of the possibility of XYY chromosome abnormalities in sexual offenders. (c) 2006 Wiley-Liss, Inc.

  3. Condensin II Resolves Chromosomal Associations to Enable Anaphase I Segregation in Drosophila Male Meiosis

    PubMed Central

    Hartl, Tom A.; Sweeney, Sarah J.; Knepler, Peter J.; Bosco, Giovanni

    2008-01-01

    Several meiotic processes ensure faithful chromosome segregation to create haploid gametes. Errors to any one of these processes can lead to zygotic aneuploidy with the potential for developmental abnormalities. During prophase I of Drosophila male meiosis, each bivalent condenses and becomes sequestered into discrete chromosome territories. Here, we demonstrate that two predicted condensin II subunits, Cap-H2 and Cap-D3, are required to promote territory formation. In mutants of either subunit, territory formation fails and chromatin is dispersed throughout the nucleus. Anaphase I is also abnormal in Cap-H2 mutants as chromatin bridges are found between segregating heterologous and homologous chromosomes. Aneuploid sperm may be generated from these defects as they occur at an elevated frequency and are genotypically consistent with anaphase I segregation defects. We propose that condensin II–mediated prophase I territory formation prevents and/or resolves heterologous chromosomal associations to alleviate their potential interference in anaphase I segregation. Furthermore, condensin II–catalyzed prophase I chromosome condensation may be necessary to resolve associations between paired homologous chromosomes of each bivalent. These persistent chromosome associations likely consist of DNA entanglements, but may be more specific as anaphase I bridging was rescued by mutations in the homolog conjunction factor teflon. We propose that the consequence of condensin II mutations is a failure to resolve heterologous and homologous associations mediated by entangled DNA and/or homolog conjunction factors. Furthermore, persistence of homologous and heterologous interchromosomal associations lead to anaphase I chromatin bridging and the generation of aneuploid gametes. PMID:18927632

  4. Chromosome and molecular abnormalities in myelodysplastic syndromes.

    PubMed

    Fenaux, Pierre

    2001-06-01

    Cytogenetic abnormalities are seen in approximately 50% of cases of myelodysplastic syndrome (MDS) and 80% of cases of secondary MDS (following chemotherapy or radiotherapy). These abnormalities generally consist of partial or complete chromosome deletion or addition (del5q, -7, +8, -Y, del20q), whereas balanced or unbalanced translocations are rarely found in MDS. Fluorescence hybridization techniques (fluorescence in situ hybridization [FISH], multiplex FISH, and spectral karyotyping) are useful in detecting chromosomal anomalies in cases in which few mitoses are obtained or rearrangements are complex. Ras mutations are the molecular abnormalities most frequently found in MDS, followed by p15 gene hypermethylation, FLT3 duplications, and p53 mutations, but none of these abnormalities are specific for MDS. The rare cases of balanced translocations in MDS have allowed the identification of genes whose rearrangements appear to play a role in the pathogenesis of some cases of MDS. These genes include MDS1-EVI1 in t(3;3) or t(3;21) translocations, TEL in t(5;12), HIP1 in t(5;7), MLF1 in t(3;5), and MEL1 in t(1;3). Genes more frequently implicated in the pathogenesis of MDS cases, such as those involving del5q, remain unknown, although some candidate genes are currently being studied. Cytogenetic and known molecular abnormalities generally carry a poor prognosis in MDS and can be incorporated into prognostic scoring systems such as the International Prognostic Scoring System.

  5. Distinct chromosome segregation roles for spindle checkpoint proteins.

    PubMed

    Warren, Cheryl D; Brady, D Michelle; Johnston, Raymond C; Hanna, Joseph S; Hardwick, Kevin G; Spencer, Forrest A

    2002-09-01

    The spindle checkpoint plays a central role in the fidelity of chromosome transmission by ensuring that anaphase is initiated only after kinetochore-microtubule associations of all sister chromatid pairs are complete. In this study, we find that known spindle checkpoint proteins do not contribute equally to chromosome segregation fidelity in Saccharomyces cerevisiae. Loss of Bub1 or Bub3 protein elicits the largest effect. Analysis of Bub1p reveals the presence of two molecular functions. An N-terminal 608-amino acid (nonkinase) portion of the protein supports robust checkpoint activity, and, as expected, contributes to chromosome segregation. A C-terminal kinase-encoding segment independently contributes to chromosome segregation through an unknown mechanism. Both molecular functions depend on association with Bub3p. A 156-amino acid fragment of Bub1p functions in Bub3p binding and in kinetochore localization by one-hybrid assay. An adjacent segment is required for Mad1p binding, detected by deletion analysis and coimmunoprecipitation. Finally, overexpression of wild-type BUB1 or MAD3 genes leads to chromosome instability. Analysis of this activity indicates that the Bub3p-binding domain of Bub1p contributes to this phenotype through disruption of checkpoint activity as well as through introduction of kinetochore or spindle damage.

  6. Distinct Chromosome Segregation Roles for Spindle Checkpoint Proteins

    PubMed Central

    Warren, Cheryl D.; Brady, D. Michelle; Johnston, Raymond C.; Hanna, Joseph S.; Hardwick, Kevin G.; Spencer, Forrest A.

    2002-01-01

    The spindle checkpoint plays a central role in the fidelity of chromosome transmission by ensuring that anaphase is initiated only after kinetochore-microtubule associations of all sister chromatid pairs are complete. In this study, we find that known spindle checkpoint proteins do not contribute equally to chromosome segregation fidelity in Saccharomyces cerevisiae. Loss of Bub1 or Bub3 protein elicits the largest effect. Analysis of Bub1p reveals the presence of two molecular functions. An N-terminal 608-amino acid (nonkinase) portion of the protein supports robust checkpoint activity, and, as expected, contributes to chromosome segregation. A C-terminal kinase-encoding segment independently contributes to chromosome segregation through an unknown mechanism. Both molecular functions depend on association with Bub3p. A 156-amino acid fragment of Bub1p functions in Bub3p binding and in kinetochore localization by one-hybrid assay. An adjacent segment is required for Mad1p binding, detected by deletion analysis and coimmunoprecipitation. Finally, overexpression of wild-type BUB1 or MAD3 genes leads to chromosome instability. Analysis of this activity indicates that the Bub3p-binding domain of Bub1p contributes to this phenotype through disruption of checkpoint activity as well as through introduction of kinetochore or spindle damage. PMID:12221113

  7. Chromosomal abnormalities as a cause of recurrent abortions in Egypt

    PubMed Central

    El-Dahtory, Faeza Abdel Mogib

    2011-01-01

    BACKGROUND: In 4%-8% of couples with recurrent abortion, at least one of the partners has chromosomal abnormality. Most spontaneous miscarriages which happen in the first and second trimesters are caused by chromosomal abnormalities. These chromosomal abnormalities may be either numerical or structural. MATERIAL AND METHODS: Cytogenetic study was done for 73 Egyptian couples who presented with recurrent abortion at Genetic Unit of Children Hospital, Mansoura University. RESULTS: We found that the frequency of chromosomal abnormalities was not significantly different from that reported worldwide. Chromosomal abnormalities were detected in 9 (6.1%) of 73 couples. Seven of chromosomal abnormalities were structural and two of them were numerical. CONCLUSION: Our results showed that 6.1% of the couples with recurrent abortion had chromosomal abnormalities, with no other abnormalities. We suggest that it is necessary to perform cytogenetic in vestigation for couples who have recurrent abortion. PMID:22090718

  8. Tumor-Specific Chromosome Mis-Segregation Controls Cancer Plasticity by Maintaining Tumor Heterogeneity

    PubMed Central

    Hu, Yuanjie; Ru, Ning; Xiao, Huasheng; Chaturbedi, Abhishek; Hoa, Neil T.; Tian, Xiao-Jun; Zhang, Hang; Ke, Chao; Yan, Fengrong; Nelson, Jodi; Li, Zhenzhi; Gramer, Robert; Yu, Liping; Siegel, Eric; Zhang, Xiaona; Jia, Zhenyu; Jadus, Martin R.; Limoli, Charles L.; Linskey, Mark E.; Xing, Jianhua; Zhou, Yi-Hong

    2013-01-01

    Aneuploidy with chromosome instability is a cancer hallmark. We studied chromosome 7 (Chr7) copy number variation (CNV) in gliomas and in primary cultures derived from them. We found tumor heterogeneity with cells having Chr7-CNV commonly occurs in gliomas, with a higher percentage of cells in high-grade gliomas carrying more than 2 copies of Chr7, as compared to low-grade gliomas. Interestingly, all Chr7-aneuploid cell types in the parental culture of established glioma cell lines reappeared in single-cell-derived subcultures. We then characterized the biology of three syngeneic glioma cultures dominated by different Chr7-aneuploid cell types. We found phenotypic divergence for cells following Chr7 mis-segregation, which benefited overall tumor growth in vitro and in vivo. Mathematical modeling suggested the involvement of chromosome instability and interactions among cell subpopulations in restoring the optimal equilibrium of tumor cell types. Both our experimental data and mathematical modeling demonstrated that the complexity of tumor heterogeneity could be enhanced by the existence of chromosomes with structural abnormality, in addition to their mis-segregations. Overall, our findings show, for the first time, the involvement of chromosome instability in maintaining tumor heterogeneity, which underlies the enhanced growth, persistence and treatment resistance of cancers. PMID:24282558

  9. Down's Syndrome and Leukemia: Mechanism of Additional Chromosomal Abnormalities

    ERIC Educational Resources Information Center

    And Others; Goh, Kong-oo

    1978-01-01

    Chromosomal abnormalities, some appearing in a stepwise clonal evoluation, were found in five Down's syndrome patients (35 weeks to 12 years old), four with acute leukemia and one with abnormal regulation of leukopoiesis. (Author/SBH)

  10. The prevalence of chromosomal abnormalities in subgroups of infertile men.

    PubMed

    Dul, E C; Groen, H; van Ravenswaaij-Arts, C M A; Dijkhuizen, T; van Echten-Arends, J; Land, J A

    2012-01-01

    The prevalence of chromosomal abnormalities is assumed to be higher in infertile men and inversely correlated with sperm concentration. Although guidelines advise karyotyping infertile men, karyotyping is costly, therefore it would be of benefit to identify men with the highest risk of chromosomal abnormalities, possibly by using parameters other than sperm concentration. The aim of this study was to evaluate several clinical parameters in azoospermic and non-azoospermic men, in order to assess the prevalence of chromosomal abnormalities in different subgroups of infertile men. In a retrospective cohort of 1223 azoospermic men and men eligible for ICSI treatment, we studied sperm parameters, hormone levels and medical history for an association with chromosomal abnormalities. The prevalence of chromosomal abnormalities in the cohort was 3.1%. No association was found between chromosomal abnormalities and sperm volume, concentration, progressive motility or total motile sperm count. Azoospermia was significantly associated with the presence of a chromosomal abnormality [15.2%, odds ratio (OR) 7.70, P < 0.001]. High gonadotrophin levels were also associated with an increased prevalence of chromosomal abnormalities (OR 2.96, P = 0.013). Azoospermic men with a positive andrologic history had a lower prevalence of chromosomal abnormalities than azoospermic men with an uneventful history (OR 0.28, P = 0.047). In non-azoospermic men, we found that none of the studied variables were associated with the prevalence of chromosomal abnormalities. We show that the highest prevalence of chromosomal abnormalities is found in hypergonadotrophic azoospermic men with an uneventful andrologic history.

  11. Chromosome abnormalities in sperm of individuals with constitutional sex chromosomal abnormalities.

    PubMed

    Ferlin, A; Garolla, A; Foresta, C

    2005-01-01

    The most common type of karyotype abnormality detected in infertile subjects is represented by Klinefelter's syndrome, and the most frequent non-chromosomal alteration is represented by Y chromosome long arm microdeletions. Here we report our experience and a review of the literature on sperm sex chromosome aneuploidies in these two conditions. Non mosaic 47,XXY Klinefelter patients (12 subjects) show a significantly lower percentage of normal Y-bearing sperm and slightly higher percentage of normal X-bearing sperm. Consistent with the hypothesis that 47,XXY germ cells may undergo and complete meiosis, aneuploidy rate for XX- and XY-disomies is also increased with respect to controls, whereas the percentage of YY-disomies is normal. Aneuploidy rates in men with mosaic 47,XXY/46,XY (11 subjects) are lower than those observed in men with non-mosaic Klinefelter's syndrome, and only the frequency of XY-disomic sperm is significantly higher with respect to controls. Although the great majority of children born by intracytoplasmic sperm injection from Klinefelter subjects are chromosomally normal, the risk of producing offspring with chromosome aneuploidies is significant. Men with Y chromosome microdeletions (14 subjects) showed a reduction of normal Y-bearing sperm, and an increase in nullisomic and XY-disomic sperm, suggesting an instability of the deleted Y chromosome causing its loss in germ cells, and meiotic alterations leading to XY non-disjunction. Intracytoplasmic injection of sperm from Y-deleted men will therefore transmit the deletion to male children, and therefore the spermatogenic impairment, but raises also concerns of generating 45,X and 47,XXY embryos. Copyright 2005 S. Karger AG, Basel.

  12. A Case of ADHD and a Major Y Chromosome Abnormality

    ERIC Educational Resources Information Center

    Mulligan, Aisling; Gill, Michael; Fitzgerald, Michael

    2008-01-01

    Background: ADHD is a common, heritable disorder of childhood. Sex chromosome abnormalities are relatively rare conditions that are sometimes associated with behavioral disorders. Method: The authors present a male child with ADHD and a major de-novo Y chromosome abnormality consisting of deletion of the long arm and duplication of the short arm.…

  13. Visualizing how cancer chromosome abnormalities form in living cells

    Cancer.gov

    For the first time, scientists have directly observed events that lead to the formation of a chromosome abnormality that is often found in cancer cells. The abnormality, called a translocation, occurs when part of a chromosome breaks off and becomes attac

  14. Chromosome segregation drives division site selection in Streptococcus pneumoniae.

    PubMed

    van Raaphorst, Renske; Kjos, Morten; Veening, Jan-Willem

    2017-07-18

    Accurate spatial and temporal positioning of the tubulin-like protein FtsZ is key for proper bacterial cell division. Streptococcus pneumoniae (pneumococcus) is an oval-shaped, symmetrically dividing opportunistic human pathogen lacking the canonical systems for division site control (nucleoid occlusion and the Min-system). Recently, the early division protein MapZ was identified and implicated in pneumococcal division site selection. We show that MapZ is important for proper division plane selection; thus, the question remains as to what drives pneumococcal division site selection. By mapping the cell cycle in detail, we show that directly after replication both chromosomal origin regions localize to the future cell division sites, before FtsZ. Interestingly, Z-ring formation occurs coincidently with initiation of DNA replication. Perturbing the longitudinal chromosomal organization by mutating the condensin SMC, by CRISPR/Cas9-mediated chromosome cutting, or by poisoning DNA decatenation resulted in mistiming of MapZ and FtsZ positioning and subsequent cell elongation. Together, we demonstrate an intimate relationship between DNA replication, chromosome segregation, and division site selection in the pneumococcus, providing a simple way to ensure equally sized daughter cells.

  15. Who should be screened for chromosomal abnormalities before ICSI treatment?

    PubMed

    Dul, E C; van Ravenswaaij-Arts, C M A; Groen, H; van Echten-Arends, J; Land, J A

    2010-11-01

    Guidelines on karyotyping infertile men before ICSI treatment are not consistent. Most guidelines recommend chromosomal screening in azoospermic and severe oligozoospermic men, because they are assumed to have the highest risk of abnormalities. We performed a retrospective cohort study in azoospermic men and men eligible for ICSI. We determined the prevalence of chromosomal abnormalities in relation to sperm concentration and compared our data to studies in the literature. A high prevalence of chromosomal abnormalities in azoospermic men was found, but no difference in the prevalence of abnormalities was seen between different sperm concentration categories in non-azoospermic men. This raises the question of who should be screened for chromosomal abnormalities before ICSI treatment. Considering the costs and benefits, we would propose limiting screening to infertile couples with non-obstructive azoospermia.

  16. Association of MTHFR polymorphisms and chromosomal abnormalities in leukemia.

    PubMed

    Sinthuwiwat, Thivaratana; Poowasanpetch, Phanasit; Wongngamrungroj, Angsana; Soonklang, Kamonwan; Promso, Somying; Auewarakul, Chirayu; Tocharoentanaphol, Chintana

    2012-01-01

    Genetic variation in MTHFR gene might explain the interindividual differences in the reduction of DNA repaired and the increase of chromosome breakage and damage. Nowadays, chromosomal rearrangement is recognized as a major cause of lymphoid malignancies. In addition, the association of MTHFR polymorphisms with aneuploidy was found in several studies, making the MTHFR gene as a good candidate for leukemia etiology. Therefore, in this study, we investigated the common sequence variation, 677C>T and 1298A>C in the MTHFR gene of 350 fixed cell specimens archived after chromosome analysis. The distribution of the MTHFR polymorphisms frequency was compared in leukemic patients with structural chromosome abnormality and chromosome aneuploidy, as well as in those with no evidence of chromosome abnormalities. We observed a significant decrease in the distribution of T allele in 677C>T polymorphisms among patients with chromosomal abnormalities including both structural aberration and aneuploidy. The same significance result also found in patients with structural aberration when compare with the normal karyotype patients. Suggesting that polymorphism in the MTHFR gene was involved in chromosome abnormalities of leukemia. However, further investigation on the correlation with the specific types of chromosomal aberrations is needed.

  17. The FANC pathway and BLM collaborate during mitosis to prevent micro-nucleation and chromosome abnormalities.

    PubMed

    Naim, Valeria; Rosselli, Filippo

    2009-06-01

    Loss-of-function of caretaker genes characterizes a group of cancer predisposition diseases that feature cellular hypersensitivity to DNA damage and chromosome fragility; this group includes Fanconi anaemia and Bloom syndrome. The products of the 13 FANC genes (mutated in Fanconi anaemia), which constitute the 'FANC' pathway, and BLM (the RecQ helicase mutated in Bloom syndrome) are thought to collaborate during the S phase of the cell cycle, preventing chromosome instability. Recently, BLM has been implicated in the completion of sister chromatid separation during mitosis, a complex process in which precise regulation and execution is crucial to preserve genomic stability. Here we show for the first time a role for the FANC pathway in chromosome segregation during mitotic cell division. FANCD2, a key component of the pathway, localizes to discrete spots on mitotic chromosomes. FANCD2 chromosomal localization is responsive to replicative stress and specifically targets aphidicolin (APH)-induced chromatid gaps and breaks. Our data indicate that the FANC pathway is involved in rescuing abnormal anaphase and telophase (ana-telophase) cells, limiting aneuploidy and reducing chromosome instability in daughter cells. We further address a cooperative role for the FANC pathway and BLM in preventing micronucleation, through FANC-dependent targeting of BLM to non-centromeric abnormal structures induced by replicative stress. We reveal new crosstalk between FANC and BLM proteins, extending their interaction beyond the S-phase rescue of damaged DNA to the safeguarding of chromosome stability during mitosis.

  18. Elevating the frequency of chromosome mis-segregation as a strategy to kill tumor cells

    PubMed Central

    Janssen, Aniek; Kops, Geert J. P. L.; Medema, René H.

    2009-01-01

    The mitotic checkpoint has evolved to prevent chromosome mis-segregations by delaying mitosis when unattached chromosomes are present. Inducing severe chromosome segregation errors by ablating the mitotic checkpoint causes cell death. Here we have analyzed the consequences of gradual increases in chromosome segregation errors on the viability of tumor cells and normal human fibroblasts. Partial reduction of essential mitotic checkpoint components in four tumor cell lines caused mild chromosome mis-segregations, but no lethality. These cells were, however, remarkably more sensitive to low doses of taxol, which enhanced the amount and severity of chromosome segregation errors. Sensitization to taxol was achieved by reducing levels of Mps1 or BubR1, proteins having dual roles in checkpoint activation and chromosome alignment, but not by reducing Mad2, functioning solely in the mitotic checkpoint. Moreover, we find that untransformed human fibroblasts with reduced Mps1 levels could not be sensitized to sublethal doses of taxol. Thus, targeting the mitotic checkpoint and chromosome alignment simultaneously may selectively kill tumor cells by enhancing chromosome mis-segregations. PMID:19855003

  19. Persistence of chromosomal abnormalities additional to the Philadelphia chromosome after Philadelphia chromosome disappearance during imatinib therapy for chronic myeloid leukemia.

    PubMed

    Zaccaria, Alfonso; Valenti, Anna Maria; Donti, Emilio; Gozzetti, Alessandro; Ronconi, Sonia; Spedicato, Francesco

    2007-04-01

    Five Philadelphia chromosome positive (Ph+) chronic myeloid leukemia (CML) patients with additional chromosome abnormalities at diagnosis have been followed during Imatinib therapy. In all, the Ph chromosome disappeared, while the 5 cases, additional abnormalities [dup(1); del(5), +8 (2 patients) and +14] persisted in the subsequent studies, performed over a period of 11 to 49 months, either alone or together with a karyotypically normal cell population. This finding is consistent with a secondary origin of the Ph chromosome in these patients. It is still to early to evaluate the possible prognostic value of these additional abnormalities.

  20. Genomic imprinting as a probable explanation for variable intrafamilial phenotypic expression of an unusual chromosome 3 abnormality

    SciTech Connect

    Fryburg, J.S.; Shashi, V.; Kelly, T.E.

    1994-09-01

    We present a 4 generation family in which an abnormal chromosome 3 with dup(3)(q25) segregated from great-grandmother to grandmother to son without phenotypic effect. The son`s 2 daughters have dysmorphic features, mild developmental delays and congenital heart disease. Both girls have the abnormal chr. 3 but are the only family members with the abnormality to have phenotypic effects. An unaffected son of the father has normal chromosomes. FISH with whole chromosome paints for chromosomes 1, 2, 6, 7, 8, 14, 18, and 22 excluded these as the origin of the extra material. Chromosome 3-specific paint revealed a uniform pattern, suggestingmore » that the extra material is from chromosome 3. Comparative genomic hybridization and DNA studies are pending. Possible explanations for the discordance in phenotypes between the 4th generation offspring and the first 3 generations include: an undetected rearrangement in the previous generations that is unbalanced in the two affected individuals; the chromosome abnormality may be a benign variant and unrelated to the phenotype; or, most likely, genomic imprinting. Genomic imprinting is suggested by the observation that a phenotypic effect was only seen after the chromosome was inherited from the father. The mothers in the first two generations appear to have passed the abnormal chr. 3 on without effect. This is an opportunity to delineate a region of the human genome affected by paternal imprinting.« less

  1. Chromosomal abnormalities, meiotic behavior and fertility in domestic animals.

    PubMed

    Villagómez, D A F; Pinton, A

    2008-01-01

    Since the advent of the surface microspreading technique for synaptonemal complex analysis, increasing interest in describing the synapsis patterns of chromosome abnormalities associated with fertility of domestic animals has been noticed during the past three decades. In spite of the number of scientific reports describing the occurrence of structural chromosome abnormalities, their meiotic behavior and gametic products, little is known in domestic animal species about the functional effects of such chromosome aberrations in the germ cell line of carriers. However, some interesting facts gained from recent and previous studies on the meiotic behavior of chromosome abnormalities of domestic animals permit us to discuss, in the frame of recent knowledge emerging from mouse and human investigations, the possible mechanism implicated in the well known association between meiotic disruption and chromosome pairing failure. New cytogenetic techniques, based on molecular and immunofluorescent analyses, are allowing a better description of meiotic processes, including gamete production. The present communication reviews the knowledge of the meiotic consequences of chromosome abnormalities in domestic animals. Copyright 2008 S. Karger AG, Basel.

  2. Insensitivity of chromosome I and the cell cycle to blockage of replication and segregation of Vibrio cholerae chromosome II.

    PubMed

    Kadoya, Ryosuke; Chattoraj, Dhruba K

    2012-01-01

    Vibrio cholerae has two chromosomes (chrI and chrII) whose replication and segregation are under different genetic controls. The region covering the replication origin of chrI resembles that of the Escherichia coli chromosome, and both origins are under control of the highly conserved initiator, DnaA. The origin region of chrII resembles that of plasmids that have iterated initiator-binding sites (iterons) and is under control of the chrII-specific initiator, RctB. Both chrI and chrII encode chromosome-specific orthologs of plasmid partitioning proteins, ParA and ParB. Here, we have interfered with chrII replication, segregation, or both, using extra copies of sites that titrate RctB or ParB. Under these conditions, replication and segregation of chrI remain unaffected for at least 1 cell cycle. In this respect, chrI behaves similarly to the E. coli chromosome when plasmid maintenance is disturbed in the same cell. Apparently, no checkpoint exists to block cell division before the crippled chromosome is lost by a failure to replicate or to segregate. Whether blocking chrI replication can affect chrII replication remains to be tested. Chromosome replication, chromosome segregation, and cell division are the three main events of the cell cycle. They occur in an orderly fashion once per cell cycle. How the sequence of events is controlled is only beginning to be answered in bacteria. The finding of bacteria that possess more than one chromosome raises the important question: how are different chromosomes coordinated in their replication and segregation? It appears that in the evolution of the two-chromosome genome of V. cholerae, either the secondary chromosome adapted to the main chromosome to ensure its maintenance or it is maintained independently, as are bacterial plasmids. An understanding of chromosome coordination is expected to bear on the evolutionary process of chromosome acquisition and on the efficacy of possible strategies for selective elimination of a

  3. Spatiotemporal dynamics of Aurora B-PLK1-MCAK signaling axis orchestrates kinetochore bi-orientation and faithful chromosome segregation

    PubMed Central

    Shao, Hengyi; Huang, Yuejia; Zhang, Liangyu; Yuan, Kai; Chu, Youjun; Dou, Zhen; Jin, Changjiang; Garcia-Barrio, Minerva; Liu, Xing; Yao, Xuebiao

    2015-01-01

    Chromosome segregation in mitosis is orchestrated by the dynamic interactions between the kinetochore and spindle microtubules. The microtubule depolymerase mitotic centromere-associated kinesin (MCAK) is a key regulator for an accurate kinetochore-microtubule attachment. However, the regulatory mechanism underlying precise MCAK depolymerase activity control during mitosis remains elusive. Here, we describe a novel pathway involving an Aurora B-PLK1 axis for regulation of MCAK activity in mitosis. Aurora B phosphorylates PLK1 on Thr210 to activate its kinase activity at the kinetochores during mitosis. Aurora B-orchestrated PLK1 kinase activity was examined in real-time mitosis using a fluorescence resonance energy transfer-based reporter and quantitative analysis of native PLK1 substrate phosphorylation. Active PLK1, in turn, phosphorylates MCAK at Ser715 which promotes its microtubule depolymerase activity essential for faithful chromosome segregation. Importantly, inhibition of PLK1 kinase activity or expression of a non-phosphorylatable MCAK mutant prevents correct kinetochore-microtubule attachment, resulting in abnormal anaphase with chromosome bridges. We reason that the Aurora B-PLK1 signaling at the kinetochore orchestrates MCAK activity, which is essential for timely correction of aberrant kinetochore attachment to ensure accurate chromosome segregation during mitosis. PMID:26206521

  4. Abnormal meiosis in an intersectional allotriploid of Populus L. and segregation of ploidy levels in 2x × 3x progeny

    PubMed Central

    Huo, Beibei; Liu, Wanting; Li, Daili; Liao, Ling

    2017-01-01

    Triploid plants are usually highly aborted owing to unbalanced meiotic chromosome segregation, but limited viable gametes can participate in the transition to different ploidy levels. In this study, numerous meiotic abnormalities were found with high frequency in an intersectional allotriploid poplar (Populus alba × P. berolinensis ‘Yinzhong’), including univalents, precocious chromosome migration, lagging chromosomes, chromosome bridges, micronuclei, and precocious cytokinesis, indicating high genetic imbalance in this allotriploid. Some micronuclei trigger mini-spindle formation in metaphase II and participate in cytokinesis to form polyads with microcytes. Unbalanced chromosome segregation and chromosome elimination resulted in the formation of microspores with aneuploid chromosome sets. Fusion of sister nuclei occurs in microsporocytes with precocious cytokinesis, which could form second meiotic division restitution (SDR)-type gametes. However, SDR-type gametes likely contain incomplete chromosome sets due to unbalanced segregation of homologous chromosomes during the first meiotic division in triploids. Misorientation of spindles during the second meiotic division, such as fused and tripolar spindles with low frequency, could result in the formation of first meiotic division restitution (FDR)-type unreduced gametes, which most likely contain three complete chromosome sets. Although ‘Yinzhong’ yields 88.7% stainable pollen grains with wide diameter variation from 23.9 to 61.3 μm, the pollen viability is poor (2.78% ± 0.38). A cross of ‘Yinzhong’ pollen with a diploid female clone produced progeny with extensive segregation of ploidy levels, including 29 diploids, 18 triploids, 4 tetraploids, and 48 aneuploids, suggesting the formation of viable aneuploidy and unreduced pollen in ‘Yinzhong’. Individuals with different chromosome compositions are potential to analyze chromosomal function and to integrate the chromosomal dosage variation into

  5. Molecular cytogenetic studies in structural abnormalities of chromosome 13

    SciTech Connect

    Lozzio, C.B.; Bamberger, E.; Anderson, I.

    1994-09-01

    A partial trisomy 13 was detected prenatally in an amniocentesis performed due to the following ultrasound abnormalities: open sacral neural tube defect (NTD), a flattened cerebellum, and lumbar/thoracic hemivertebrae. Elevated AFP and positive acetylcholinesterase in amniotic fluid confirmed the open NTD. Chromosome analysis showed an extra acrocentric chromosome marker. FISH analysis with the painting probe 13 showed that most of the marker was derived from this chromosome. Chromosomes on the parents revealed that the mother had a balanced reciprocal translocation t(2;13)(q23;q21). Dual labeling with painting chromosomes 2 and 13 on cells from the mother and from the amniotic fluid identifiedmore » the marker as a der(13)t(2;13)(p23;q21). Thus, the fetus had a partial trisomy 13 and a small partial trisomy 2p. The maternal grandfather was found to be a carrier for this translocation. Fetal demise occurred a 29 weeks of gestation. The fetus had open lumbar NTD and showed dysmorphic features, overlapping fingers and imperforate anus. This woman had a subsequent pregnancy and chorionic villi sample showed that this fetus was normal. Another case with an abnormal chromosome 13 was a newborn with partial monosomy 13 due to the presence of a ring chromosome 13. This infant had severe intrauterine growth retardation, oligohydramnios, dysmorphic features and multiple congenital microphthalmia, congenital heart disease, absent thumbs and toes and cervical vertebral anomalies. Chromosome studies in blood and skin fibroblast cultures showed that one chromosome 3 was replaced by a ring chromosome of various sizes. This ring was confirmed to be derived from chromosome 13 using the centromeric 21/13 probe.« less

  6. Female phenotype and multiple abnormalities in sibs with a Y chromosome and partial X chromosome duplication: H--Y antigen and Xg blood group findings.

    PubMed Central

    Bernstein, R; Jenkins, T; Dawson, B; Wagner, J; Dewald, G; Koo, G C; Wachtel, S S

    1980-01-01

    A mentally retarded female child with multiple congenital abnormalities had an abnormal X chromosome and a Y chromosome; the karyotype was interpreted as 46,dup(X)(p21 leads to pter)Y. Prenatal chromosome studies in a later pregnancy indicated the same chromosomal abnormality in the fetus. The fetus and proband had normal female genitalia and ovarian tissue. H--Y antigen was virtually absent in both sibs, a finding consistent with the view that testis-determining genes of the Y chromosome may be suppressed by regulatory elements of the X. The abnormal X chromosome was present in the mother, the maternal grandmother, and a female sib: all were phenotypically normal and showed the karyotype 46,Xdup(X)(p21 leads to pter) with non-random inactivation of the abnormal X. Anomalous segregation of the Xga allele suggests that the Xg locus was involved in the inactivation process or that crossing-over at meiosis occurred. Images PMID:7193738

  7. Direct evidence of a role for heterochromatin in meiotic chromosome segregation.

    PubMed

    Dernburg, A F; Sedat, J W; Hawley, R S

    1996-07-12

    We have investigated the mechanism that enables achiasmate chromosomes to segregate from each other at meiosis I in D. melanogaster oocytes. Using novel cytological methods, we asked whether nonexchange chromosomes are paired prior to disjunction. Our results show that the heterochromatin of homologous chromosomes remains associated throughout prophase until metaphase I regardless of whether they undergo exchange, suggesting that homologous recognition can lead to segregation even in the absence of chiasmata. However, partner chromosomes lacking homology do not pair prior to disjunction. Furthermore, euchromatic synapsis is not maintained throughout prophase. These observations provide a physical demonstration that homologous and heterologous achiasmate segregations occur by different mechanisms and establish a role for heterochromatin in maintaining the alignment of chromosomes during meiosis.

  8. Chromosome Mis-segregation Generates Cell-Cycle-Arrested Cells with Complex Karyotypes that Are Eliminated by the Immune System.

    PubMed

    Santaguida, Stefano; Richardson, Amelia; Iyer, Divya Ramalingam; M'Saad, Ons; Zasadil, Lauren; Knouse, Kristin A; Wong, Yao Liang; Rhind, Nicholas; Desai, Arshad; Amon, Angelika

    2017-06-19

    Aneuploidy, a state of karyotype imbalance, is a hallmark of cancer. Changes in chromosome copy number have been proposed to drive disease by modulating the dosage of cancer driver genes and by promoting cancer genome evolution. Given the potential of cells with abnormal karyotypes to become cancerous, do pathways that limit the prevalence of such cells exist? By investigating the immediate consequences of aneuploidy on cell physiology, we identified mechanisms that eliminate aneuploid cells. We find that chromosome mis-segregation leads to further genomic instability that ultimately causes cell-cycle arrest. We further show that cells with complex karyotypes exhibit features of senescence and produce pro-inflammatory signals that promote their clearance by the immune system. We propose that cells with abnormal karyotypes generate a signal for their own elimination that may serve as a means for cancer cell immunosurveillance. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. "Idiopathic" mental retardation and new chromosomal abnormalities

    PubMed Central

    2010-01-01

    Mental retardation is a heterogeneous condition, affecting 1-3% of general population. In the last few years, several emerging clinical entities have been described, due to the advent of newest genetic techniques, such as array Comparative Genomic Hybridization. The detection of cryptic microdeletion/microduplication abnormalities has allowed genotype-phenotype correlations, delineating recognizable syndromic conditions that are herein reviewed. With the aim to provide to Paediatricians a combined clinical and genetic approach to the child with cognitive impairment, a practical diagnostic algorithm is also illustrated. The use of microarray platforms has further reduced the percentage of "idiopathic" forms of mental retardation, previously accounted for about half of total cases. We discussed the putative pathways at the basis of remaining "pure idiopathic" forms of mental retardation, highlighting possible environmental and epigenetic mechanisms as causes of altered cognition. PMID:20152051

  10. Dbl2 Regulates Rad51 and DNA Joint Molecule Metabolism to Ensure Proper Meiotic Chromosome Segregation

    PubMed Central

    Hyppa, Randy W.; Benko, Zsigmond; Misova, Ivana; Schleiffer, Alexander; Smith, Gerald R.; Gregan, Juraj

    2016-01-01

    To identify new proteins required for faithful meiotic chromosome segregation, we screened a Schizosaccharomyces pombe deletion mutant library and found that deletion of the dbl2 gene led to missegregation of chromosomes during meiosis. Analyses of both live and fixed cells showed that dbl2Δ mutant cells frequently failed to segregate homologous chromosomes to opposite poles during meiosis I. Removing Rec12 (Spo11 homolog) to eliminate meiotic DNA double-strand breaks (DSBs) suppressed the segregation defect in dbl2Δ cells, indicating that Dbl2 acts after the initiation of meiotic recombination. Analyses of DSBs and Holliday junctions revealed no significant defect in their formation or processing in dbl2Δ mutant cells, although some Rec12-dependent DNA joint molecules persisted late in meiosis. Failure to segregate chromosomes in the absence of Dbl2 correlated with persistent Rad51 foci, and deletion of rad51 or genes encoding Rad51 mediators also suppressed the segregation defect of dbl2Δ. Formation of foci of Fbh1, an F-box helicase that efficiently dismantles Rad51-DNA filaments, was impaired in dbl2Δ cells. Our results suggest that Dbl2 is a novel regulator of Fbh1 and thereby Rad51-dependent DSB repair required for proper meiotic chromosome segregation and viable sex cell formation. The wide conservation of these proteins suggests that our results apply to many species. PMID:27304859

  11. Chromosomal abnormalities are associated with aging and cancer

    Cancer.gov

    Two new studies have found that large structural abnormalities in chromosomes, some of which have been associated with increased risk of cancer, can be detected in a small fraction of people without a prior history of cancer. The studies found that these

  12. Mechanisms and consequences of paternally transmitted chromosomal abnormalities

    SciTech Connect

    Marchetti, F; Wyrobek, A J

    Paternally transmitted chromosomal damage has been associated with pregnancy loss, developmental and morphological defects, infant mortality, infertility, and genetic diseases in the offspring including cancer. There is epidemiological evidence linking paternal exposure to occupational or environmental agents with an increased risk of abnormal reproductive outcomes. There is also a large body of literature on germ cell mutagenesis in rodents showing that treatment of male germ cells with mutagens has dramatic consequences on reproduction producing effects such as those observed in human epidemiological studies. However, we know very little about the etiology, transmission and early embryonic consequences of paternally-derived chromosomal abnormalities.more » The available evidence suggests that: (1) there are distinct patterns of germ cell-stage differences in the sensitivity of induction of transmissible genetic damage with male postmeiotic cells being the most sensitive; (2) cytogenetic abnormalities at first metaphase after fertilization are critical intermediates between paternal exposure and abnormal reproductive outcomes; and, (3) there are maternally susceptibility factors that may have profound effects on the amount of sperm DNA damage that is converted into chromosomal aberrations in the zygote and directly affect the risk for abnormal reproductive outcomes.« less

  13. Tripolar chromosome segregation drives the association between maternal genotype at variants spanning PLK4 and aneuploidy in human preimplantation embryos.

    PubMed

    McCoy, Rajiv C; Newnham, Louise J; Ottolini, Christian S; Hoffmann, Eva R; Chatzimeletiou, Katerina; Cornejo, Omar E; Zhan, Qiansheng; Zaninovic, Nikica; Rosenwaks, Zev; Petrov, Dmitri A; Demko, Zachary P; Sigurjonsson, Styrmir; Handyside, Alan H

    2018-04-24

    Aneuploidy is prevalent in human embryos and is the leading cause of pregnancy loss. Many aneuploidies arise during oogenesis, increasing with maternal age. Superimposed on these meiotic aneuploidies are frequent errors occurring during early mitotic divisions, contributing to widespread chromosomal mosaicism. Here we reanalyzed a published dataset comprising preimplantation genetic testing for aneuploidy in 24,653 blastomere biopsies from day-3 cleavage-stage embryos, as well as 17,051 trophectoderm biopsies from day-5 blastocysts. We focused on complex abnormalities that affected multiple chromosomes simultaneously, seeking insights into their formation. In addition to well-described patterns such as triploidy and haploidy, we identified 4.7% of blastomeres possessing characteristic hypodiploid karyotypes. We inferred this signature to have arisen from tripolar chromosome segregation in normally-fertilized diploid zygotes or their descendant diploid cells. This could occur via segregation on a tripolar mitotic spindle or by rapid sequential bipolar mitoses without an intervening S-phase. Both models are consistent with time-lapse data from an intersecting set of 77 cleavage-stage embryos, which were enriched for the tripolar signature among embryos exhibiting abnormal cleavage. The tripolar signature was strongly associated with common maternal genetic variants spanning the centrosomal regulator PLK4, driving the association we previously reported with overall mitotic errors. Our findings are consistent with the known capacity of PLK4 to induce tripolar mitosis or precocious M-phase upon dysregulation. Together, our data support tripolar chromosome segregation as a key mechanism generating complex aneuploidy in cleavage-stage embryos and implicate maternal genotype at a quantitative trait locus spanning PLK4 as a factor influencing its occurrence.

  14. Telomere dysfunction and chromosome structure modulate the contribution of individual chromosomes in abnormal nuclear morphologies.

    PubMed

    Pampalona, J; Soler, D; Genescà, A; Tusell, L

    2010-01-05

    The cytokinesis-block micronucleus assay has emerged as a biomarker of chromosome damage relevant to cancer. Although it was initially developed to measure micronuclei, it is also useful for measuring nucleoplasmic bridges and nuclear buds. Abnormal nuclear morphologies are frequently observed in malignant tissues and short-term tumour cell cultures. Changes in chromosome structure and number resulting from chromosome instability are important factors in oncogenesis. Telomeres have become key players in the initiation of chromosome instability related to carcinogenesis by means of breakage-fusion-bridge cycles. To better understand the connection between telomere dysfunction and the appearance of abnormal nuclear morphologies, we have characterised the presence of micronuclei, nucleoplasmic bridges and nuclear buds in human mammary primary epithelial cells. These cells can proliferate beyond the Hayflick limit by spontaneously losing expression of the p16(INK4a) protein. Progressive telomere shortening leads to the loss of the capping function, and the appearance of end-to-end chromosome fusions that can enter into breakage-fusion-bridge cycles generating massive chromosomal instability. In human mammary epithelial cells, different types of abnormal nuclear morphologies were observed, however only nucleoplasmatic bridges and buds increased significantly with population doublings. Fluorescent in situ hybridisation using centromeric and painting specific probes for chromosomes with eroded telomeres has revealed that these chromosomes are preferentially included in the different types of abnormal nuclear morphologies observed, thus reflecting their common origin. Accordingly, real-time imaging of cell divisions enabled us to determine that anaphase bridge resolution was mainly through chromatin breakage and the formation of symmetric buds in daughter nuclei. Few micronuclei emerged in this cell system thus validating the scoring of nucleoplasmic bridges and nuclear

  15. Nuclear envelope expansion is crucial for proper chromosomal segregation during a closed mitosis.

    PubMed

    Takemoto, Ai; Kawashima, Shigehiro A; Li, Juan-Juan; Jeffery, Linda; Yamatsugu, Kenzo; Elemento, Olivier; Nurse, Paul

    2016-03-15

    Here, we screened a 10,371 library of diverse molecules using a drug-sensitive fission yeast strain to identify compounds which cause defects in chromosome segregation during mitosis. We identified a phosphorium-ylide-based compound Cutin-1 which inhibits nuclear envelope expansion and nuclear elongation during the closed mitosis of fission yeast, and showed that its target is the β-subunit of fatty acid synthase. A point mutation in the dehydratase domain of Fas1 conferred in vivo and in vitro resistance to Cutin-1. Time-lapse photomicrography showed that the bulk of the chromosomes were only transiently separated during mitosis, and nucleoli separation was defective. Subsequently sister chromatids re-associated leading to chromosomal mis-segregation. These segregation defects were reduced when the nuclear volume was increased and were increased when the nuclear volume was reduced. We propose that there needs to be sufficient nuclear volume to allow the nuclear elongation necessary during a closed mitosis to take place for proper chromosome segregation, and that inhibition of fatty acid synthase compromises nuclear elongation and leads to defects in chromosomal segregation. © 2016. Published by The Company of Biologists Ltd.

  16. GTSE1 tunes microtubule stability for chromosome alignment and segregation by inhibiting the microtubule depolymerase MCAK

    PubMed Central

    Bendre, Shweta; Hall, Conrad; Lin, Yu-Chih

    2016-01-01

    The dynamic regulation of microtubules (MTs) during mitosis is critical for accurate chromosome segregation and genome stability. Cancer cell lines with hyperstabilized kinetochore MTs have increased segregation errors and elevated chromosomal instability (CIN), but the genetic defects responsible remain largely unknown. The MT depolymerase MCAK (mitotic centromere-associated kinesin) can influence CIN through its impact on MT stability, but how its potent activity is controlled in cells remains unclear. In this study, we show that GTSE1, a protein found overexpressed in aneuploid cancer cell lines and tumors, regulates MT stability during mitosis by inhibiting MCAK MT depolymerase activity. Cells lacking GTSE1 have defects in chromosome alignment and spindle positioning as a result of MT instability caused by excess MCAK activity. Reducing GTSE1 levels in CIN cancer cell lines reduces chromosome missegregation defects, whereas artificially inducing GTSE1 levels in chromosomally stable cells elevates chromosome missegregation and CIN. Thus, GTSE1 inhibition of MCAK activity regulates the balance of MT stability that determines the fidelity of chromosome alignment, segregation, and chromosomal stability. PMID:27881713

  17. Direct kinetochore-spindle pole connections are not required for chromosome segregation.

    PubMed

    Sikirzhytski, Vitali; Magidson, Valentin; Steinman, Jonathan B; He, Jie; Le Berre, Maël; Tikhonenko, Irina; Ault, Jeffrey G; McEwen, Bruce F; Chen, James K; Sui, Haixin; Piel, Matthieu; Kapoor, Tarun M; Khodjakov, Alexey

    2014-07-21

    Segregation of genetic material occurs when chromosomes move to opposite spindle poles during mitosis. This movement depends on K-fibers, specialized microtubule (MT) bundles attached to the chromosomes' kinetochores. A long-standing assumption is that continuous K-fibers connect every kinetochore to a spindle pole and the force for chromosome movement is produced at the kinetochore and coupled with MT depolymerization. However, we found that chromosomes still maintained their position at the spindle equator during metaphase and segregated properly during anaphase when one of their K-fibers was severed near the kinetochore with a laser microbeam. We also found that, in normal fully assembled spindles, K-fibers of some chromosomes did not extend to the spindle pole. These K-fibers connected to adjacent K-fibers and/or nonkinetochore MTs. Poleward movement of chromosomes with short K-fibers was uncoupled from MT depolymerization at the kinetochore. Instead, these chromosomes moved by dynein-mediated transport of the entire K-fiber/kinetochore assembly. Thus, at least two distinct parallel mechanisms drive chromosome segregation in mammalian cells.

  18. The induction of chromosomal abnormalities by inhalational anaesthetics.

    PubMed

    Grant, C J; Powell, J N; Radford, S G

    1977-06-01

    When Vicia faba root tips are exposed for 2 h to clinically useful concentrations of halothane or methoxyflurane in air, or to halothane in 80% nitrous oxide/20% oxygen, there is a transient increase in mitotic index and then abnormal interphase cells are produced in proportion to the anaesthetic concentrations. After exposure there is a period of mitotic inhibition during which the cells become partially synchronised. When colchicine-metaphase cells collected 28 h after exposure are compared with controls and with metaphases collected only 4 h after exposure, they show a significant increase in the incidence of aneuploidy, tetraploidy and the results of chromosome breakage. It is suggested that all the abnormalities seen can be accounted for by the effects of the anaesthetics on spindle movements, and that at the concentrations used the anaesthetics have no mutagenic effects on chromosomes in interphase.

  19. Sex- and Gamete-Specific Patterns of X Chromosome Segregation in a Trioecious Nematode.

    PubMed

    Tandonnet, Sophie; Farrell, Maureen C; Koutsovoulos, Georgios D; Blaxter, Mark L; Parihar, Manish; Sadler, Penny L; Shakes, Diane C; Pires-daSilva, Andre

    2018-01-08

    Three key steps in meiosis allow diploid organisms to produce haploid gametes: (1) homologous chromosomes (homologs) pair and undergo crossovers; (2) homologs segregate to opposite poles; and (3) sister chromatids segregate to opposite poles. The XX/XO sex determination system found in many nematodes [1] facilitates the study of meiosis because variation is easily recognized [2-4]. Here we show that meiotic segregation of X chromosomes in the trioecious nematode Auanema rhodensis [5] varies according to sex (hermaphrodite, female, or male) and type of gametogenesis (oogenesis or spermatogenesis). In this species, XO males exclusively produce X-bearing sperm [6, 7]. The unpaired X precociously separates into sister chromatids, which co-segregate with the autosome set to generate a functional haplo-X sperm. The other set of autosomes is discarded into a residual body. Here we explore the X chromosome behavior in female and hermaphrodite meioses. Whereas X chromosomes segregate following the canonical pattern during XX female oogenesis to yield haplo-X oocytes, during XX hermaphrodite oogenesis they segregate to the first polar body to yield nullo-X oocytes. Thus, crosses between XX hermaphrodites and males yield exclusively male progeny. During hermaphrodite spermatogenesis, the sister chromatids of the X chromosomes separate during meiosis I, and homologous X chromatids segregate to the functional sperm to create diplo-X sperm. Given these intra-species, intra-individual, and intra-gametogenesis variations in the meiotic program, A. rhodensis is an ideal model for studying the plasticity of meiosis and how it can be modulated. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  20. Direct kinetochore–spindle pole connections are not required for chromosome segregation

    PubMed Central

    Sikirzhytski, Vitali; Magidson, Valentin; Steinman, Jonathan B.; He, Jie; Le Berre, Maël; Tikhonenko, Irina; Ault, Jeffrey G.; McEwen, Bruce F.; Chen, James K.; Sui, Haixin; Piel, Matthieu; Kapoor, Tarun M.

    2014-01-01

    Segregation of genetic material occurs when chromosomes move to opposite spindle poles during mitosis. This movement depends on K-fibers, specialized microtubule (MT) bundles attached to the chromosomes′ kinetochores. A long-standing assumption is that continuous K-fibers connect every kinetochore to a spindle pole and the force for chromosome movement is produced at the kinetochore and coupled with MT depolymerization. However, we found that chromosomes still maintained their position at the spindle equator during metaphase and segregated properly during anaphase when one of their K-fibers was severed near the kinetochore with a laser microbeam. We also found that, in normal fully assembled spindles, K-fibers of some chromosomes did not extend to the spindle pole. These K-fibers connected to adjacent K-fibers and/or nonkinetochore MTs. Poleward movement of chromosomes with short K-fibers was uncoupled from MT depolymerization at the kinetochore. Instead, these chromosomes moved by dynein-mediated transport of the entire K-fiber/kinetochore assembly. Thus, at least two distinct parallel mechanisms drive chromosome segregation in mammalian cells. PMID:25023516

  1. Meiosis I chromosome segregation is established through regulation of microtubule–kinetochore interactions

    PubMed Central

    Miller, Matthew P; Ünal, Elçin; Brar, Gloria A; Amon, Angelika

    2012-01-01

    During meiosis, a single round of DNA replication is followed by two consecutive rounds of nuclear divisions called meiosis I and meiosis II. In meiosis I, homologous chromosomes segregate, while sister chromatids remain together. Determining how this unusual chromosome segregation behavior is established is central to understanding germ cell development. Here we show that preventing microtubule–kinetochore interactions during premeiotic S phase and prophase I is essential for establishing the meiosis I chromosome segregation pattern. Premature interactions of kinetochores with microtubules transform meiosis I into a mitosis-like division by disrupting two key meiosis I events: coorientation of sister kinetochores and protection of centromeric cohesin removal from chromosomes. Furthermore we find that restricting outer kinetochore assembly contributes to preventing premature engagement of microtubules with kinetochores. We propose that inhibition of microtubule–kinetochore interactions during premeiotic S phase and prophase I is central to establishing the unique meiosis I chromosome segregation pattern. DOI: http://dx.doi.org/10.7554/eLife.00117.001 PMID:23275833

  2. Effects of antitopoisomerase drugs on chromosome recombinations and segregation in grasshopper

    SciTech Connect

    Palitti, F.; Motta, S.; Grazioso, C.

    1993-12-31

    The role of different cellular functions which are required for the production of euploid cells can be studied through the use of mutants that are defective in the control of both the meiotic and mitotic cell cycle or through the use of compounds which interface with the various cellular targets which have a role in the segregation of chromosomes. The role of the achromatic part of the mitotic apparatus in the production of aneuploidy is well recognized. Substantial progress has been made in understanding the role of the chromatic part, for example, there are observations that disturbances in the normalmore » {open_quotes}metabolism{close_quotes} of the chromosomes (i.e. chromosome condensation, defective DNA repair or recombination) can affect chromosome segregation. Between the processes of both meiosis and mitosis that lead to nuclear division there are, however, important differences.« less

  3. Cytomixis and meiotic abnormalities during microsporogenesis are responsible for male sterility and chromosome variations in Houttuynia cordata.

    PubMed

    Guan, J-Z; Wang, J-J; Cheng, Z-H; Liu, Y; Li, Z-Y

    2012-01-17

    Houttuynia cordata (Saururaceae) is a leaf vegetable and a medicinal herb througout much of Asia. Cytomixis and meiotic abnormalities during microsporogenesis were found in two populations of H. cordata with different ploidy levels (2n = 38, 96). Cytomixis occurred in pollen mother cells during meiosis at high frequencies and with variable degrees of chromatin/chromosome transfer. Meiotic abnormalities, such as chromosome laggards, asymmetric segregation and polyads, also prevailed in pollen mother cells at metaphase of the first division and later stages. They were caused by cytomixis and resulted in very low pollen viability and male sterility. Pollen mother cells from the population with 2n = 38 showed only simultaneous cytokinesis, but most pollen mother cells from the population with 2n = 96 showed successive cytokinesis; a minority underwent simultaneous cytokinesis. Cytomixis and irregular meiotic divisions appear to be the origin of the intraspecific polyploidy in this species, which has large variations in chromosome numbers.

  4. Determinants of parental decisions to abort for chromosome abnormalities.

    PubMed

    Drugan, A; Greb, A; Johnson, M P; Krivchenia, E L; Uhlmann, W R; Moghissi, K S; Evans, M I

    1990-08-01

    Parental decisions concerning the continuation of pregnancy following prenatal detection of abnormal chromosomes were evaluated for 80 patients whose diagnosis and prenatal counselling were performed in our centre. Twenty-two anomalies were diagnosed by chorionic villus sampling (CVS) and 58 by amniocentesis. The severity of the chromosome anomaly and associated ultrasound findings in the first vs. second trimester were correlated with patients' decisions. No difference was found in the likelihood of parental decisions to interrupt or continue a pregnancy between CVS and amniocentesis for either the 'severe' or the 'questionable' group of chromosome anomalies. Ninety-three per cent of patients with severe prognosis and 27 per cent with questionable prognosis opted for pregnancy termination (p less than 0.0001). The association of ultrasound anomalies and termination was highly significant (p less than 0.001). The severity of the chromosome anomaly, and, to a lesser extent, the visualization of anomalies on ultrasound were the major determinants of parental decisions to terminate the pregnancy. The diagnosis of an anomaly in the first trimester was no more likely ito lead to a termination of pregnancy than in the second trimester.

  5. Autophagy is required for efficient meiosis progression and proper meiotic chromosome segregation in fission yeast.

    PubMed

    Matsuhara, Hirotada; Yamamoto, Ayumu

    2016-01-01

    Autophagy is a conserved intracellular degradation system, which contributes to development and differentiation of various organisms. Yeast cells undergo meiosis under nitrogen-starved conditions and require autophagy for meiosis initiation. However, the precise roles of autophagy in meiosis remain unclear. Here, we show that autophagy is required for efficient meiosis progression and proper meiotic chromosome segregation in fission yeast. Autophagy-defective strains bearing a mutation in the autophagy core factor gene atg1, atg7, or atg14 exhibit deformed nuclear structures during meiosis. These mutant cells require an extracellular nitrogen supply for meiosis progression following their entry into meiosis and show delayed meiosis progression even with a nitrogen supply. In addition, they show frequent chromosome dissociation from the spindle together with spindle overextension, forming extra nuclei. Furthermore, Aurora kinase, which regulates chromosome segregation and spindle elongation, is significantly increased at the centromere and spindle in the mutant cells. Aurora kinase down-regulation eliminated delayed initiation of meiosis I and II, chromosome dissociation, and spindle overextension, indicating that increased Aurora kinase activity may cause these aberrances in the mutant cells. Our findings show a hitherto unrecognized relationship of autophagy with the nuclear structure, regulation of cell cycle progression, and chromosome segregation in meiosis. © 2015 The Molecular Biology Society of Japan and Wiley Publishing Asia Pty Ltd.

  6. A septal chromosome segregator protein evolved into a conjugative DNA-translocator protein

    PubMed Central

    Sepulveda, Edgardo; Vogelmann, Jutta

    2011-01-01

    Streptomycetes, Gram-positive soil bacteria well known for the production of antibiotics feature a unique conjugative DNA transfer system. In contrast to classical conjugation which is characterized by the secretion of a pilot protein covalently linked to a single-stranded DNA molecule, in Streptomyces a double-stranded DNA molecule is translocated during conjugative transfer. This transfer involves a single plasmid encoded protein, TraB. A detailed biochemical and biophysical characterization of TraB, revealed a close relationship to FtsK, mediating chromosome segregation during bacterial cell division. TraB translocates plasmid DNA by recognizing 8-bp direct repeats located in a specific plasmid region clt. Similar sequences accidentally also occur on chromosomes and have been shown to be bound by TraB. We suggest that TraB mobilizes chromosomal genes by the interaction with these chromosomal clt-like sequences not relying on the integration of the conjugative plasmid into the chromosome. PMID:22479692

  7. Actin homolog MreB affects chromosome segregation by regulating topoisomerase IV in Escherichia coli.

    PubMed

    Madabhushi, Ram; Marians, Kenneth J

    2009-01-30

    In Escherichia coli, topoisomerase IV, a type II topoisomerase, mediates the resolution of topological linkages between replicated daughter chromosomes and is essential for chromosome segregation. Topo IV activity is restricted to only a short interval late in the cell cycle. However, the mechanism that confers this temporal regulation is unknown. Here we report that the bacterial actin homolog MreB participates in the temporal oscillation of Topo IV activity. We show that mreB mutant strains are deficient in Topo IV activity. In addition, we demonstrate that, depending upon whether it is in a monomeric or polymerized state, MreB affects Topo IV activity differentially. In addition, MreB physically interacts with the ParC subunit of Topo IV. Together, these results may explain how dynamics of the bacterial cytoskeleton are coordinated with the timing of chromosome segregation.

  8. Sorting nexin 9 recruits clathrin heavy chain to the mitotic spindle for chromosome alignment and segregation.

    PubMed

    Ma, Maggie P C; Robinson, Phillip J; Chircop, Megan

    2013-01-01

    Sorting nexin 9 (SNX9) and clathrin heavy chain (CHC) each have roles in mitosis during metaphase. Since the two proteins directly interact for their other cellular function in endocytosis we investigated whether they also interact for metaphase and operate on the same pathway. We report that SNX9 and CHC functionally interact during metaphase in a specific molecular pathway that contributes to stabilization of mitotic spindle kinetochore (K)-fibres for chromosome alignment and segregation. This function is independent of their endocytic role. SNX9 residues in the clathrin-binding low complexity domain are required for CHC association and for targeting both CHC and transforming acidic coiled-coil protein 3 (TACC3) to the mitotic spindle. Mutation of these sites to serine increases the metaphase plate width, indicating inefficient chromosome congression. Therefore SNX9 and CHC function in the same molecular pathway for chromosome alignment and segregation, which is dependent on their direct association.

  9. Sorting Nexin 9 Recruits Clathrin Heavy Chain to the Mitotic Spindle for Chromosome Alignment and Segregation

    PubMed Central

    Ma, Maggie P. C.; Robinson, Phillip J.; Chircop, Megan

    2013-01-01

    Sorting nexin 9 (SNX9) and clathrin heavy chain (CHC) each have roles in mitosis during metaphase. Since the two proteins directly interact for their other cellular function in endocytosis we investigated whether they also interact for metaphase and operate on the same pathway. We report that SNX9 and CHC functionally interact during metaphase in a specific molecular pathway that contributes to stabilization of mitotic spindle kinetochore (K)-fibres for chromosome alignment and segregation. This function is independent of their endocytic role. SNX9 residues in the clathrin-binding low complexity domain are required for CHC association and for targeting both CHC and transforming acidic coiled-coil protein 3 (TACC3) to the mitotic spindle. Mutation of these sites to serine increases the metaphase plate width, indicating inefficient chromosome congression. Therefore SNX9 and CHC function in the same molecular pathway for chromosome alignment and segregation, which is dependent on their direct association. PMID:23861900

  10. Histone H1 is essential for mitotic chromosome architecture and segregation in Xenopus laevis egg extracts

    PubMed Central

    Maresca, Thomas J.; Freedman, Benjamin S.; Heald, Rebecca

    2005-01-01

    During cell division, condensation and resolution of chromosome arms and the assembly of a functional kinetochore at the centromere of each sister chromatid are essential steps for accurate segregation of the genome by the mitotic spindle, yet the contribution of individual chromatin proteins to these processes is poorly understood. We have investigated the role of embryonic linker histone H1 during mitosis in Xenopus laevis egg extracts. Immunodepletion of histone H1 caused the assembly of aberrant elongated chromosomes that extended off the metaphase plate and outside the perimeter of the spindle. Although functional kinetochores assembled, aligned, and exhibited poleward movement, long and tangled chromosome arms could not be segregated in anaphase. Histone H1 depletion did not significantly affect the recruitment of known structural or functional chromosomal components such as condensins or chromokinesins, suggesting that the loss of H1 affects chromosome architecture directly. Thus, our results indicate that linker histone H1 plays an important role in the structure and function of vertebrate chromosomes in mitosis. PMID:15967810

  11. Chromosomal abnormalities in HPV-16-immortalized oral epithelial cells.

    PubMed

    Oda, D; Bigler, L; Mao, E J; Disteche, C M

    1996-09-01

    Human papilloma virus (HPV) type 16 has an established association with anogenital carcinoma, and to some extent with human oral squamous cell carcinoma. We hypothesize that HPV type 16 is capable of inducing chromosomal and cell cycle changes in cultured oral epithelial cells. Normal human oral epithelia] cells were immortalized with recombinant retrovirus containing the E6/E7 open reading frames of HPV type 16. These cells have been in culture for more than 350 passages and over 4 years. Flow cytometry demonstrated an average of 42% nuclear aneuploidy in HPV 16-immortalized cells; 16% in normal controls (probably tetrasomy). Cytogenetic analysis demonstrated significant progression of chromosomal abnormalities. Cells at early passage (p10) showed trisomy 20, with no other major changes. At passage 18, trisomy 1q and monosomy 13 were seen in addition to trisomy 20. At passage 61 there were two distinct cell populations ('a' and 'b'), with multiple chromosomal changes including trisomy 5q,14,20 in one line and 7p,9q,llq in the other. Both populations had monosomy 3p, with monosomy 8p in one population and monosomy 13 in the other. At passage 136, the cells were essentially identical to population 'b' of passage 61. At this passage, mutation of the p53 gene was detected at codon 273 of exon 8, with G to T conversion (Arg to Leu). This was absent in the normal cells from which this line was developed. Passage 262 contained the two major cell populations, each with a sub-group with additional chromosomal changes such as 10p monosomy. Cells from passages 217 and 305 were injected into nude mice a year apart. Both failed to produce tumors, as did normal cells. In conclusion, we present an HPV type 16-immortalized oral epithelial cell line (IHGK) with extensive and progressive chromosomal abnormalities, invasive growth in culture and yet no tumor formation in nude mice. We suggest that the question as to whether HPV alone can induce transformation is still open.

  12. Phosphorylation of PP1 Regulator Sds22 by PLK1 Ensures Accurate Chromosome Segregation.

    PubMed

    Duan, Hequan; Wang, Chunli; Wang, Ming; Gao, Xinjiao; Yan, Maomao; Akram, Saima; Peng, Wei; Zou, Hanfa; Wang, Dong; Zhou, Jiajia; Chu, Youjun; Dou, Zhen; Barrett, Gregory; Green, Hadiyah-Nichole; Wang, Fangjun; Tian, Ruijun; He, Ping; Wang, Wenwen; Liu, Xing; Yao, Xuebiao

    2016-09-30

    During cell division, accurate chromosome segregation is tightly regulated by Polo-like kinase 1 (PLK1) and opposing activities of Aurora B kinase and protein phosphatase 1 (PP1). However, the regulatory mechanisms underlying the aforementioned hierarchical signaling cascade during mitotic chromosome segregation have remained elusive. Sds22 is a conserved regulator of PP1 activity, but how it regulates PP1 activity in space and time during mitosis remains elusive. Here we show that Sds22 is a novel and cognate substrate of PLK1 in mitosis, and the phosphorylation of Sds22 by PLK1 elicited an inhibition of PP1-mediated dephosphorylation of Aurora B at threonine 232 (Thr 232 ) in a dose-dependent manner. Overexpression of a phosphomimetic mutant of Sds22 causes a dramatic increase in mitotic delay, whereas overexpression of a non-phosphorylatable mutant of Sds22 results in mitotic arrest. Mechanistically, the phosphorylation of Sds22 by PLK1 strengthens the binding of Sds22 to PP1 and inhibits the dephosphorylation of Thr 232 of Aurora B to ensure a robust, error-free metaphase-anaphase transition. These findings delineate a conserved signaling hierarchy that orchestrates dynamic protein phosphorylation and dephosphorylation of critical mitotic regulators during chromosome segregation to guard chromosome stability. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  13. The SUMO pathway is essential for nuclear integrity and chromosome segregation in mice.

    PubMed

    Nacerddine, Karim; Lehembre, François; Bhaumik, Mantu; Artus, Jérôme; Cohen-Tannoudji, Michel; Babinet, Charles; Pandolfi, Pier Paolo; Dejean, Anne

    2005-12-01

    Covalent modification by SUMO regulates a wide range of cellular processes, including transcription, cell cycle, and chromatin dynamics. To address the biological function of the SUMO pathway in mammals, we generated mice deficient for the SUMO E2-conjugating enzyme Ubc9. Ubc9-deficient embryos die at the early postimplantation stage. In culture, Ubc9 mutant blastocysts are viable, but fail to expand after 2 days and show apoptosis of the inner cell mass. Loss of Ubc9 leads to major chromosome condensation and segregation defects. Ubc9-deficient cells also show severe defects in nuclear organization, including nuclear envelope dysmorphy and disruption of nucleoli and PML nuclear bodies. Moreover, RanGAP1 fails to accumulate at the nuclear pore complex in mutant cells that show a collapse in Ran distribution. Together, these findings reveal a major role for Ubc9, and, by implication, for the SUMO pathway, in nuclear architecture and function, chromosome segregation, and embryonic viability in mammals.

  14. Chromosomes

    MedlinePlus

    ... Sheets A Brief Guide to Genomics About NHGRI Research About the International HapMap Project Biological Pathways Chromosome Abnormalities Chromosomes Cloning Comparative Genomics DNA Microarray Technology DNA Sequencing Deoxyribonucleic Acid ( ...

  15. Chromosome abnormalities and the genetics of congenital corneal opacification

    PubMed Central

    Mataftsi, A.; Islam, L.; Kelberman, D.; Sowden, J.C.

    2011-01-01

    Congenital corneal opacification (CCO) encompasses a broad spectrum of disorders that have different etiologies, including genetic and environmental. Terminology used in clinical phenotyping is commonly not specific enough to describe separate entities, for example both the terms Peters anomaly and sclerocornea have been ascribed to a clinical picture of total CCO, without investigating the presence or absence of iridocorneal adhesions. This is not only confusing but also unhelpful in determining valid genotype-phenotype correlations, and thereby revealing clues for pathogenesis. We undertook a systematic review of the literature focusing on CCO as part of anterior segment developmental anomalies (ASDA), and analyzed its association specifically with chromosomal abnormalities. Genes previously identified as being associated with CCO are also summarized. All reports were critically appraised to classify phenotypes according to described features, rather than the given diagnosis. Some interesting associations were found, and are discussed. PMID:21738392

  16. Chromosome abnormalities and the genetics of congenital corneal opacification.

    PubMed

    Mataftsi, A; Islam, L; Kelberman, D; Sowden, J C; Nischal, K K

    2011-01-01

    Congenital corneal opacification (CCO) encompasses a broad spectrum of disorders that have different etiologies, including genetic and environmental. Terminology used in clinical phenotyping is commonly not specific enough to describe separate entities, for example both the terms Peters anomaly and sclerocornea have been ascribed to a clinical picture of total CCO, without investigating the presence or absence of iridocorneal adhesions. This is not only confusing but also unhelpful in determining valid genotype-phenotype correlations, and thereby revealing clues for pathogenesis. We undertook a systematic review of the literature focusing on CCO as part of anterior segment developmental anomalies (ASDA), and analyzed its association specifically with chromosomal abnormalities. Genes previously identified as being associated with CCO are also summarized. All reports were critically appraised to classify phenotypes according to described features, rather than the given diagnosis. Some interesting associations were found, and are discussed.

  17. Beyond Trisomy 21: Phenotypic Variability in People with Down Syndrome Explained by Further Chromosome Mis-segregation and Mosaic Aneuploidy

    PubMed Central

    Potter, Huntington

    2017-01-01

    Phenotypic variability is a fundamental feature of the human population and is particularly evident among people with Down syndrome and/or Alzheimer’s disease. Herein, we review current theories of the potential origins of this phenotypic variability and propose a novel mechanism based on our finding that the Alzheimer’s disease-associated Aβ peptide, encoded on chromosome 21, disrupts the mitotic spindle, induces abnormal chromosome segregation, and produces mosaic populations of aneuploid cells in all tissues of people with Alzheimer’s disease and in mouse and cell models thereof. Thus, individuals exposed to increased levels of the Aβ peptide should accumulate mosaic populations of aneuploid cells, with different chromosomes affected in different tissues and in different individuals. Specifically, people with Down syndrome, who express elevated levels of Aβ peptide throughout their lifetimes, would be predicted to accumulate additional types of aneuploidy, beyond trisomy 21 and including changes in their trisomy 21 status, in mosaic cell populations. Such mosaic aneuploidy would introduce a novel form of genetic variability that could potentially underlie much of the observed phenotypic variability among people with Down syndrome, and possibly also among people with Alzheimer’s disease. This mosaic aneuploidy theory of phenotypic variability in Down syndrome is supported by several observations, makes several testable predictions, and identifies a potential approach to reducing the frequency of some of the most debilitating features of Down syndrome, including Alzheimer’s disease. PMID:29516054

  18. Strand-seq: a unifying tool for studies of chromosome segregation

    PubMed Central

    Falconer, Ester; Lansdorp, Peter M.

    2013-01-01

    Non random segregation of sister chromatids has been implicated to help specify daughter cell fate (the Silent Sister Hypothesis [1]) or to protect the genome of long-lived stem cells (the Immortal Strand Hypothesis [2]). The idea that sister chromatids are non-randomly segregated into specific daughter cells is only marginally supported by data in sporadic and often contradictory studies. As a result, the field has moved forward rather slowly. The advent of being able to directly label and differentiate sister chromatids in vivo using fluorescence in situ hybridization [3] was a significant advance for such studies. However, this approach is limited by the need for large tracks of unidirectional repeats on chromosomes and the reliance on quantitative imaging of fluorescent probes and rigorous statistical analysis to discern between the two competing hypotheses. A novel method called Strand-seq which uses next-generation sequencing to assay sister chromatid inheritance patterns independently for each chromosome [4] offers a comprehensive approach to test for non-random segregation. In addition Strand-seq enables studies on the deposition of chromatin marks in relation to DNA replication. This method is expected to help unify the field by testing previous claims of non-random segregation in an unbiased way in many model systems in vitro and in vivo. PMID:23665005

  19. Strand-seq: a unifying tool for studies of chromosome segregation.

    PubMed

    Falconer, Ester; Lansdorp, Peter M

    2013-01-01

    Non random segregation of sister chromatids has been implicated to help specify daughter cell fate (the Silent Sister Hypothesis [1]) or to protect the genome of long-lived stem cells (the Immortal Strand Hypothesis [2]). The idea that sister chromatids are non-randomly segregated into specific daughter cells is only marginally supported by data in sporadic and often contradictory studies. As a result, the field has moved forward rather slowly. The advent of being able to directly label and differentiate sister chromatids in vivo using fluorescence in situ hybridization [3] was a significant advance for such studies. However, this approach is limited by the need for large tracks of unidirectional repeats on chromosomes and the reliance on quantitative imaging of fluorescent probes and rigorous statistical analysis to discern between the two competing hypotheses. A novel method called Strand-seq which uses next-generation sequencing to assay sister chromatid inheritance patterns independently for each chromosome [4] offers a comprehensive approach to test for non-random segregation. In addition Strand-seq enables studies on the deposition of chromatin marks in relation to DNA replication. This method is expected to help unify the field by testing previous claims of non-random segregation in an unbiased way in many model systems in vitro and in vivo. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  20. CENP-E Kinesin Interacts with SKAP Protein to Orchestrate Accurate Chromosome Segregation in Mitosis*

    PubMed Central

    Huang, Yuejia; Wang, Wenwen; Yao, Phil; Wang, Xiwei; Liu, Xing; Zhuang, Xiaoxuan; Yan, Feng; Zhou, Jinhua; Du, Jian; Ward, Tarsha; Zou, Hanfa; Zhang, Jiancun; Fang, Guowei; Ding, Xia; Dou, Zhen; Yao, Xuebiao

    2012-01-01

    Mitotic chromosome segregation is orchestrated by the dynamic interaction of spindle microtubules with the kinetochore. Although previous studies show that the mitotic kinesin CENP-E forms a link between attachment of the spindle microtubule to the kinetochore and the mitotic checkpoint signaling cascade, the molecular mechanism underlying dynamic kinetochore-microtubule interactions in mammalian cells remains elusive. Here, we identify a novel interaction between CENP-E and SKAP that functions synergistically in governing dynamic kinetochore-microtubule interactions. SKAP binds to the C-terminal tail of CENP-E in vitro and is essential for an accurate kinetochore-microtubule attachment in vivo. Immunoelectron microscopic analysis indicates that SKAP is a constituent of the kinetochore corona fibers of mammalian centromeres. Depletion of SKAP or CENP-E by RNA interference results in a dramatic reduction of inter-kinetochore tension, which causes chromosome mis-segregation with a prolonged delay in achieving metaphase alignment. Importantly, SKAP binds to microtubules in vitro, and this interaction is synergized by CENP-E. Based on these findings, we propose that SKAP cooperates with CENP-E to orchestrate dynamic kinetochore-microtubule interaction for faithful chromosome segregation. PMID:22110139

  1. Abnormal chromosome behavior in human oocytes which remained unfertilized during human in vitro fertilization.

    PubMed

    Spielmann, H; Krüger, C; Stauber, M; Vogel, R

    1985-09-01

    Chromosomal abnormalities and abnormal embryonic development have previously been observed after human in vitro fertilization (IVF). Chromosomal abnormalities may arise not only after fertilization but even earlier during meiotic maturation of human oocytes in culture. Since chromosomal analysis is simple in oocytes during meiotic maturation, the chromosomal status was analyzed in oocytes which remained unfertilized in a human in vitro fertilization program. In 50 fertilization attempts the chromosomes of 62 unfertilized oocytes could be analyzed; 45 of them were in the process of meiotic maturation. In three oocytes two small polar bodies were observed 16-18 hr after insemination in the absence of fertilization. In one oocyte abnormal chromosome behavior was found during the first meiotic division, and in four oocytes during metaphase of the second meiotic division. These data suggest that chromosomal analysis of unfertilized oocytes in human IVF may improve the understanding human oocyte maturation and fertilization.

  2. Mad2, Bub3, and Mps1 regulate chromosome segregation and mitotic synchrony in Giardia intestinalis, a binucleate protist lacking an anaphase-promoting complex

    PubMed Central

    Vicente, Juan-Jesus; Cande, W. Zacheus

    2014-01-01

    The binucleate pathogen Giardia intestinalis is a highly divergent eukaryote with a semiopen mitosis, lacking an anaphase-promoting complex/cyclosome (APC/C) and many of the mitotic checkpoint complex (MCC) proteins. However, Giardia has some MCC components (Bub3, Mad2, and Mps1) and proteins from the cohesin system (Smc1 and Smc3). Mad2 localizes to the cytoplasm, but Bub3 and Mps1 are either located on chromosomes or in the cytoplasm, depending on the cell cycle stage. Depletion of Bub3, Mad2, or Mps1 resulted in a lowered mitotic index, errors in chromosome segregation (including lagging chromosomes), and abnormalities in spindle morphology. During interphase, MCC knockdown cells have an abnormal number of nuclei, either one nucleus usually on the left-hand side of the cell or two nuclei with one mislocalized. These results suggest that the minimal set of MCC proteins in Giardia play a major role in regulating many aspects of mitosis, including chromosome segregation, coordination of mitosis between the two nuclei, and subsequent nuclear positioning. The critical importance of MCC proteins in an organism that lacks their canonical target, the APC/C, suggests a broader role for these proteins and hints at new pathways to be discovered. PMID:25057014

  3. CDE-1 affects chromosome segregation through uridylation of CSR-1-bound siRNAs.

    PubMed

    van Wolfswinkel, Josien C; Claycomb, Julie M; Batista, Pedro J; Mello, Craig C; Berezikov, Eugene; Ketting, René F

    2009-10-02

    We have studied the function of a conserved germline-specific nucleotidyltransferase protein, CDE-1, in RNAi and chromosome segregation in C. elegans. CDE-1 localizes specifically to mitotic chromosomes in embryos. This localization requires the RdRP EGO-1, which physically interacts with CDE-1, and the Argonaute protein CSR-1. We found that CDE-1 is required for the uridylation of CSR-1 bound siRNAs, and that in the absence of CDE-1 these siRNAs accumulate to inappropriate levels, accompanied by defects in both meiotic and mitotic chromosome segregation. Elevated siRNA levels are associated with erroneous gene silencing, most likely through the inappropriate loading of CSR-1 siRNAs into other Argonaute proteins. We propose a model in which CDE-1 restricts specific EGO-1-generated siRNAs to the CSR-1 mediated, chromosome associated RNAi pathway, thus separating it from other endogenous RNAi pathways. The conserved nature of CDE-1 suggests that similar sorting mechanisms may operate in other animals, including mammals.

  4. PTEN in the maintenance of genome integrity: From DNA replication to chromosome segregation.

    PubMed

    Hou, Sheng-Qi; Ouyang, Meng; Brandmaier, Andrew; Hao, Hongbo; Shen, Wen H

    2017-10-01

    Faithful DNA replication and accurate chromosome segregation are the key machineries of genetic transmission. Disruption of these processes represents a hallmark of cancer and often results from loss of tumor suppressors. PTEN is an important tumor suppressor that is frequently mutated or deleted in human cancer. Loss of PTEN has been associated with aneuploidy and poor prognosis in cancer patients. In mice, Pten deletion or mutation drives genomic instability and tumor development. PTEN deficiency induces DNA replication stress, confers stress tolerance, and disrupts mitotic spindle architecture, leading to accumulation of structural and numerical chromosome instability. Therefore, PTEN guards the genome by controlling multiple processes of chromosome inheritance. Here, we summarize current understanding of the PTEN function in promoting high-fidelity transmission of genetic information. We also discuss the PTEN pathways of genome maintenance and highlight potential targets for cancer treatment. © 2017 WILEY Periodicals, Inc.

  5. Chromosome segregation in Archaea mediated by a hybrid DNA partition machine

    PubMed Central

    Kalliomaa-Sanford, Anne K.; Rodriguez-Castañeda, Fernando A.; McLeod, Brett N.; Latorre-Roselló, Victor; Smith, Jasmine H.; Reimann, Julia; Albers, Sonja V.; Barillà, Daniela

    2012-01-01

    Eukarya and, more recently, some bacteria have been shown to rely on a cytoskeleton-based apparatus to drive chromosome segregation. In contrast, the factors and mechanisms underpinning this fundamental process are underexplored in archaea, the third domain of life. Here we establish that the archaeon Sulfolobus solfataricus harbors a hybrid segrosome consisting of two interacting proteins, SegA and SegB, that play a key role in genome segregation in this organism. SegA is an ortholog of bacterial, Walker-type ParA proteins, whereas SegB is an archaea-specific factor lacking sequence identity to either eukaryotic or bacterial proteins, but sharing homology with a cluster of uncharacterized factors conserved in both crenarchaea and euryarchaea, the two major archaeal sub-phyla. We show that SegA is an ATPase that polymerizes in vitro and that SegB is a site-specific DNA-binding protein contacting palindromic sequences located upstream of the segAB cassette. SegB interacts with SegA in the presence of nucleotides and dramatically affects its polymerization dynamics. Our data demonstrate that SegB strongly stimulates SegA polymerization, possibly by promoting SegA nucleation and accelerating polymer growth. Increased expression levels of segAB resulted in severe growth and chromosome segregation defects, including formation of anucleate cells, compact nucleoids confined to one half of the cell compartment and fragmented nucleoids. The overall picture emerging from our findings indicates that the SegAB complex fulfills a crucial function in chromosome segregation and is the prototype of a DNA partition machine widespread across archaea. PMID:22355141

  6. Chromosome segregation in Archaea mediated by a hybrid DNA partition machine.

    PubMed

    Kalliomaa-Sanford, Anne K; Rodriguez-Castañeda, Fernando A; McLeod, Brett N; Latorre-Roselló, Victor; Smith, Jasmine H; Reimann, Julia; Albers, Sonja V; Barillà, Daniela

    2012-03-06

    Eukarya and, more recently, some bacteria have been shown to rely on a cytoskeleton-based apparatus to drive chromosome segregation. In contrast, the factors and mechanisms underpinning this fundamental process are underexplored in archaea, the third domain of life. Here we establish that the archaeon Sulfolobus solfataricus harbors a hybrid segrosome consisting of two interacting proteins, SegA and SegB, that play a key role in genome segregation in this organism. SegA is an ortholog of bacterial, Walker-type ParA proteins, whereas SegB is an archaea-specific factor lacking sequence identity to either eukaryotic or bacterial proteins, but sharing homology with a cluster of uncharacterized factors conserved in both crenarchaea and euryarchaea, the two major archaeal sub-phyla. We show that SegA is an ATPase that polymerizes in vitro and that SegB is a site-specific DNA-binding protein contacting palindromic sequences located upstream of the segAB cassette. SegB interacts with SegA in the presence of nucleotides and dramatically affects its polymerization dynamics. Our data demonstrate that SegB strongly stimulates SegA polymerization, possibly by promoting SegA nucleation and accelerating polymer growth. Increased expression levels of segAB resulted in severe growth and chromosome segregation defects, including formation of anucleate cells, compact nucleoids confined to one half of the cell compartment and fragmented nucleoids. The overall picture emerging from our findings indicates that the SegAB complex fulfills a crucial function in chromosome segregation and is the prototype of a DNA partition machine widespread across archaea.

  7. Fetal karyotyping for chromosome abnormalities after an unexplained elevated maternal serum alpha-fetoprotein screening.

    PubMed

    Feuchtbaum, L B; Cunningham, G; Waller, D K; Lustig, L S; Tompkinson, D G; Hook, E B

    1995-08-01

    To study the chromosome abnormality rate among women with elevated levels of maternal serum alpha-fetoprotein (MSAFP) and the types of chromosome abnormalities in this population, and to compare this rate with reports in the literature and the rate observed in the general population. We studied 8097 women who chose to undergo amniocentesis and fetal karyotyping after having an elevated MSAFP test of 2.5 multiples of the median (MOM) or higher. All abnormal karyotypes were reviewed and grouped according to whether the elevated MSAFP value could be explained by a ventral wall or neural tube defect. The overall chromosome abnormality rate was 13.83 per 1000 amniocenteses. The rate in the "unexplained" group was 10.92 per 1000 amniocenteses. Just over half (53%) of the abnormal karyotypes were autosomal anomalies, and 47% were sex chromosome abnormalities. The autosomal aneuploidies observed most frequently were triploidy and trisomy 13. The sex chromosome abnormalities observed most frequently were the XXY and XYY karyotypes. Women who have unexplained elevated MSAFP values of 2.5 MOM or greater have a twofold increase in the rate of chromosome abnormalities in their fetuses compared with the general population (P < or = .001). This rate is consistent with other studies that used a 2.5 MOM cutoff. Studies that used a 2.0 MOM cutoff have reported chromosome abnormality rates that do not vary from general population estimates.

  8. Different segregation patterns in five carriers due to a pericentric inversion of chromosome 1.

    PubMed

    Luo, Yuqin; Xu, Chenming; Sun, Yixi; Wang, Liya; Chen, Songchang; Jin, Fan

    2014-12-01

    Pericentric inversion can produce recombinant gametes; however, meiotic segregation studies on the relationship between the frequency of recombinants and the inverted segment size are rare. Triple-color fluorescence in situ hybridization (FISH) was performed to analyze the meiotic behavior in five inv(1) carriers with different breakpoints. Recombination gametes were absent in Patient 1, whereas the percentages of the recombinants in Patients 2, 3, 4, and 5 were of 9.2%, 15.3%, 17.3%, and 40.9%, respectively. A significant difference was present for the frequencies of the recombinant spermatozoa among the five patients (p < 0.001). For each patient, the frequency of the two types of recombinant gametes (dup(1p)/del(1q) or del(1p)/dup(1q)) did not exhibit a significant difference in comparison with the expected 1:1 ratio (p > 0.05). The meiotic segregation of nine inv(1) carriers (including those presented in this paper) is now available. A significant correlation was discovered between the rate of recombination and the proportion of the chromosome implicated in the inversion (R = 0.9435, p < 0.001). The frequency of the recombinant gametes was directly related to the proportion of the chromosome that was inverted. Sperm-FISH allowed an additional comprehension of the patterns of meiotic segregation and provided accurate genetic counseling.

  9. Clinical implications of chromosomal abnormalities in gastric adenocarcinomas

    SciTech Connect

    Wu, Chew-Wun; Chen, Gen-Der; Fann, Cathy S.-J.

    2003-06-23

    Gastric carcinoma (GC) is one of the most common malignancies worldwide and has a very poor prognosis. Genetic imbalances in 62 primary gastric adenocarcinomas of various histopathologic types and pathologic stages and six gastric cancer-derived cell lines were analyzed by comparative genomic hybridization, and the relationship of genomic abnormalities to clinical features in primary GC was evaluated at a genome-wide level. Eighty-four percent of the tumors and all six cell lines showed DNA copy number changes. The recurrent chromosomal abnormalities including gains at 15 regions and losses at 8 regions were identified. Statistical analyses revealed that gains at 17q24-qter (53more » percent), 20q13-qter (48 percent), 1p32-p36 (42 percent), 22q12-qter (27 percent), 17p13-pter (24 percent), 16p13-pter (21 percent), 6p21-pter (19 percent), 20p12-pter (19 percent), 7p21-pter (18 percent), 3q28-qter (8 percent), and 13q13-q14 (8 percent), and losses at 18q12-qter (11 percent), 3p12 (8 percent), 3p25-pter (8 percent), 5q14-q23 (8 percent), and 9p21-p23 (5 percent), are associated with unique patient or tumor-related features. GCs of differing histopathologic features were shown to be associated with distinct patterns of genetic alterations, supporting the notion that they evolve through distinct genetic pathways. Metastatic tumors were also associated with specific genetic changes. These regions may harbor candidate genes involved in the pathogenesis of this malignancy.« less

  10. Cell division patterns and chromosomal segregation defects in oral cancer stem cells.

    PubMed

    Kaseb, Hatem O; Lewis, Dale W; Saunders, William S; Gollin, Susanne M

    2016-09-01

    Oral squamous cell carcinoma (OSCC) is a serious public health problem caused primarily by smoking and alcohol consumption or human papillomavirus. The cancer stem cell (CSC) theory posits that CSCs show unique characteristics, including self-renewal and therapeutic resistance. Examining biomarkers and other features of CSCs is critical to better understanding their biology. To this end, the results show that cellular SOX2 immunostaining correlates with other CSC biomarkers in OSCC cell lines and marks the rare CSC population. To assess whether CSC division patterns are symmetrical, resulting in two CSC, or asymmetrical, leading to one CSC and one cancer cell, cell size and fluorescence intensity of mitotic cells stained with SOX2 were analyzed. Asymmetrical SOX2 distribution in ≈25% of the mitoses analyzed was detected. Chromosomal instability, some of which is caused by chromosome segregation defects (CSDs), is a feature of cancer cells that leads to altered gene copy numbers. We compare chromosomal instability (as measured by CSDs) between CSCs (SOX2+) and non-CSCs (SOX2-) from the same OSCC cell lines. CSDs were more common in non-CSCs (SOX2-) than CSCs (SOX2+) and in symmetrical CSC (SOX2+) mitotic pairs than asymmetrical CSC (SOX2+/SOX2-) mitotic pairs. CSCs showed fewer and different types of CSDs after ionizing radiation treatment than non-CSCs. Overall, these data are the first to demonstrate both symmetrical and asymmetrical cell divisions with CSDs in OSCC CSC. Further, the results suggest that CSCs may undergo altered behavior, including therapeutic resistance as a result of chromosomal instability due to chromosome segregation defects. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  11. Trypanosome outer kinetochore proteins suggest conservation of chromosome segregation machinery across eukaryotes

    PubMed Central

    D’Archivio, Simon

    2017-01-01

    Kinetochores are multiprotein complexes that couple eukaryotic chromosomes to the mitotic spindle to ensure proper segregation. The model for kinetochore assembly is conserved between humans and yeast, and homologues of several components are widely distributed in eukaryotes, but key components are absent in some lineages. The recent discovery in a lineage of protozoa called kinetoplastids of unconventional kinetochores with no apparent homology to model organisms suggests that more than one system for eukaryotic chromosome segregation may exist. In this study, we report a new family of proteins distantly related to outer kinetochore proteins Ndc80 and Nuf2. The family member in kinetoplastids, KKT-interacting protein 1 (KKIP1), associates with the kinetochore, and its depletion causes severe defects in karyokinesis, loss of individual chromosomes, and gross defects in spindle assembly or stability. Immunopurification of KKIP1 from stabilized kinetochores identifies six further components, which form part of a trypanosome outer kinetochore complex. These findings suggest that kinetochores in organisms such as kinetoplastids are built from a divergent, but not ancestrally distinct, set of components and that Ndc80/Nuf2-like proteins are universal in eukaryotic division. PMID:28034897

  12. Sex chromosome abnormalities and sterility in river buffalo.

    PubMed

    Di Meo, G P; Perucatti, A; Di Palo, R; Iannuzzi, A; Ciotola, F; Peretti, V; Neglia, G; Campanile, G; Zicarelli, L; Iannuzzi, L

    2008-01-01

    Thirteen male river buffaloes, 119 females with reproductive problems (which had reached reproductive age but had failed to become pregnant in the presence of bulls) and two male co-twins underwent both clinical and cytogenetic investigation. Clinical analyses performed by veterinary practitioners revealed normal body conformation and external genitalia for most females. However, some subjects showed some slight male traits such as large base horn circumference, prominent withers and tight pelvis. Rectal palpation revealed damage to internal sex adducts varying between atrophy of Mullerian ducts to complete lack of internal sex adducts (with closed vagina). All bulls had normal karyotypes at high resolution banding, while 25 animals (23 females and 2 male co-twins) (20.7%) with reproductive problems were found to carry the following sex chromosome abnormalities: X monosomy (2 females); X trisomy (1 female); sex reversal syndrome (2 females); and free-martinism (18 females and 2 males). All female carriers were sterile. Copyright 2008 S. Karger AG, Basel.

  13. Dialkyl phosphate urinary metabolites and chromosomal abnormalities in human sperm.

    PubMed

    Figueroa, Zaida I; Young, Heather A; Meeker, John D; Martenies, Sheena E; Barr, Dana Boyd; Gray, George; Perry, Melissa J

    2015-11-01

    The past decade has seen numerous human health studies seeking to characterize the impacts of environmental exposures, such as organophosphate (OP) insecticides, on male reproduction. Despite an extensive literature on OP toxicology, many hormone-mediated effects on the testes are not well understood. This study investigated environmental exposures to OPs and their association with the frequency of sperm chromosomal abnormalities (i.e., disomy) among adult men. Men (n=159) from a study assessing the impact of environmental exposures on male reproductive health were included in this investigation. Multi-probe fluorescence in situ hybridization (FISH) for chromosomes X, Y, and 18 was used to determine XX18, YY18, XY18 and total disomy in sperm nuclei. Urine was analyzed using gas chromatography coupled with mass spectrometry for concentrations of dialkyl phosphate (DAP) metabolites of OPs [dimethylphosphate (DMP); dimethylthiophosphate (DMTP); dimethyldithiophosphate (DMDTP); diethylphosphate (DEP); diethylthiophosphate (DETP); and diethyldithiophosphate (DEDTP)]. Poisson regression was used to model the association between OP exposures and disomy measures. Incidence rate ratios (IRRs) were calculated for each disomy type by exposure quartiles for most metabolites, controlling for age, race, BMI, smoking, specific gravity, total sperm concentration, motility, and morphology. A significant positive trend was seen for increasing IRRs by exposure quartiles of DMTP, DMDTP, DEP and DETP in XX18, YY18, XY18 and total disomy. A significant inverse association was observed between DMP and total disomy. Findings for total sum of DAP metabolites concealed individual associations as those results differed from the patterns observed for each individual metabolite. Dose-response relationships appeared nonmonotonic, with most of the increase in disomy rates occurring between the second and third exposure quartiles and without additional increases between the third and fourth

  14. A mitosis-specific and R loop-driven ATR pathway promotes faithful chromosome segregation.

    PubMed

    Kabeche, Lilian; Nguyen, Hai Dang; Buisson, Rémi; Zou, Lee

    2018-01-05

    The ataxia telangiectasia mutated and Rad3-related (ATR) kinase is crucial for DNA damage and replication stress responses. Here, we describe an unexpected role of ATR in mitosis. Acute inhibition or degradation of ATR in mitosis induces whole-chromosome missegregation. The effect of ATR ablation is not due to altered cyclin-dependent kinase 1 (CDK1) activity, DNA damage responses, or unscheduled DNA synthesis but to loss of an ATR function at centromeres. In mitosis, ATR localizes to centromeres through Aurora A-regulated association with centromere protein F (CENP-F), allowing ATR to engage replication protein A (RPA)-coated centromeric R loops. As ATR is activated at centromeres, it stimulates Aurora B through Chk1, preventing formation of lagging chromosomes. Thus, a mitosis-specific and R loop-driven ATR pathway acts at centromeres to promote faithful chromosome segregation, revealing functions of R loops and ATR in suppressing chromosome instability. Copyright © 2018, American Association for the Advancement of Science.

  15. Spindle checkpoint–independent inhibition of mitotic chromosome segregation by Drosophila Mps1

    PubMed Central

    Althoff, Friederike; Karess, Roger E.; Lehner, Christian F.

    2012-01-01

    Monopolar spindle 1 (Mps1) is essential for the spindle assembly checkpoint (SAC), which prevents anaphase onset in the presence of misaligned chromosomes. Moreover, Mps1 kinase contributes in a SAC-independent manner to the correction of erroneous initial attachments of chromosomes to the spindle. Our characterization of the Drosophila homologue reveals yet another SAC-independent role. As in yeast, modest overexpression of Drosophila Mps1 is sufficient to delay progression through mitosis during metaphase, even though chromosome congression and metaphase alignment do not appear to be affected. This delay in metaphase depends on the SAC component Mad2. Although Mps1 overexpression in mad2 mutants no longer causes a metaphase delay, it perturbs anaphase. Sister kinetochores barely move apart toward spindle poles. However, kinetochore movements can be restored experimentally by separase-independent resolution of sister chromatid cohesion. We propose therefore that Mps1 inhibits sister chromatid separation in a SAC-independent manner. Moreover, we report unexpected results concerning the requirement of Mps1 dimerization and kinase activity for its kinetochore localization in Drosophila. These findings further expand Mps1's significance for faithful mitotic chromosome segregation and emphasize the importance of its careful regulation. PMID:22553353

  16. Spindle checkpoint-independent inhibition of mitotic chromosome segregation by Drosophila Mps1.

    PubMed

    Althoff, Friederike; Karess, Roger E; Lehner, Christian F

    2012-06-01

    Monopolar spindle 1 (Mps1) is essential for the spindle assembly checkpoint (SAC), which prevents anaphase onset in the presence of misaligned chromosomes. Moreover, Mps1 kinase contributes in a SAC-independent manner to the correction of erroneous initial attachments of chromosomes to the spindle. Our characterization of the Drosophila homologue reveals yet another SAC-independent role. As in yeast, modest overexpression of Drosophila Mps1 is sufficient to delay progression through mitosis during metaphase, even though chromosome congression and metaphase alignment do not appear to be affected. This delay in metaphase depends on the SAC component Mad2. Although Mps1 overexpression in mad2 mutants no longer causes a metaphase delay, it perturbs anaphase. Sister kinetochores barely move apart toward spindle poles. However, kinetochore movements can be restored experimentally by separase-independent resolution of sister chromatid cohesion. We propose therefore that Mps1 inhibits sister chromatid separation in a SAC-independent manner. Moreover, we report unexpected results concerning the requirement of Mps1 dimerization and kinase activity for its kinetochore localization in Drosophila. These findings further expand Mps1's significance for faithful mitotic chromosome segregation and emphasize the importance of its careful regulation.

  17. Specific and non-specific interactions of ParB with DNA: implications for chromosome segregation

    PubMed Central

    Taylor, James A.; Pastrana, Cesar L.; Butterer, Annika; Pernstich, Christian; Gwynn, Emma J.; Sobott, Frank; Moreno-Herrero, Fernando; Dillingham, Mark S.

    2015-01-01

    The segregation of many bacterial chromosomes is dependent on the interactions of ParB proteins with centromere-like DNA sequences called parS that are located close to the origin of replication. In this work, we have investigated the binding of Bacillus subtilis ParB to DNA in vitro using a variety of biochemical and biophysical techniques. We observe tight and specific binding of a ParB homodimer to the parS sequence. Binding of ParB to non-specific DNA is more complex and displays apparent positive co-operativity that is associated with the formation of larger, poorly defined, nucleoprotein complexes. Experiments with magnetic tweezers demonstrate that non-specific binding leads to DNA condensation that is reversible by protein unbinding or force. The condensed DNA structure is not well ordered and we infer that it is formed by many looping interactions between neighbouring DNA segments. Consistent with this view, ParB is also able to stabilize writhe in single supercoiled DNA molecules and to bridge segments from two different DNA molecules in trans. The experiments provide no evidence for the promotion of non-specific DNA binding and/or condensation events by the presence of parS sequences. The implications of these observations for chromosome segregation are discussed. PMID:25572315

  18. Prevalence and consequences of chromosomal abnormalities in Canadian commercial swine herds.

    PubMed

    Quach, Anh T; Revay, Tamas; Villagomez, Daniel A F; Macedo, Mariana P; Sullivan, Alison; Maignel, Laurence; Wyss, Stefanie; Sullivan, Brian; King, W Allan

    2016-09-12

    Structural chromosome abnormalities are well known as factors that reduce fertility rate in domestic pigs. According to large-scale national cytogenetic screening programs that are implemented in France, it is estimated that new chromosome abnormalities occur at a rate of 0.5 % in fertility-unproven boars. This work aimed at estimating the prevalence and consequences of chromosome abnormalities in commercial swine operations in Canada. We found pig carriers at a frequency of 1.64 % (12 out of 732 boars). Carrier pigs consistently showed lower fertility values. The total number of piglets born for litters from carrier boars was between 4 and 46 % lower than the herd average. Similarly, carrier boars produced litters with a total number of piglets born alive that was between 6 and 28 % lower than the herd average. A total of 12 new structural chromosome abnormalities were identified. Reproductive performance is significantly reduced in sires with chromosome abnormalities. The incidence of such abnormal sires appears relatively high in populations without routine cytogenetic screening such as observed for Canada in this study. Systematic cytogenetic screening of potential breeding boars would minimise the risk of carriers of chromosome aberrations entering artificial insemination centres. This would avoid the large negative effects on productivity for the commercial sow herds and reduce the risk of transmitting abnormalities to future generations in nucleus farms.

  19. Long G2 accumulates recombination intermediates and disturbs chromosome segregation at dysfunction telomere in Schizosaccharomyces pombe

    SciTech Connect

    Habib, Ahmed G.K.; Masuda, Kenta; Yukawa, Masashi

    Protection of telomere (Pot1) is a single-stranded telomere binding protein which is essential for chromosome ends protection. Fission yeast Rqh1 is a member of RecQ helicases family which has essential roles in the maintenance of genomic stability and regulation of homologous recombination. Double mutant between fission yeast pot1Δ and rqh1 helicase dead (rqh1-hd) maintains telomere by homologous recombination. In pot1Δ rqh1-hd double mutant, recombination intermediates accumulate near telomere which disturb chromosome segregation and make cells sensitive to microtubule inhibitors thiabendazole (TBZ). Deletion of chk1{sup +} or mutation of its kinase domain shortens the G2 of pot1Δ rqh1-hd double mutant andmore » suppresses both the accumulation of recombination intermediates and the TBZ sensitivity of that double mutant. In this study, we asked whether the long G2 is the reason for the TBZ sensitivity of pot1Δ rqh1-hd double mutant. We found that shortening the G2 of pot1Δ rqh1-hd double mutant by additional mutations of wee1 and mik1 or gain of function mutation of Cdc2 suppresses both the accumulation of recombination intermediates and the TBZ sensitivity of pot1Δ rqh1-hd double mutant. Our results suggest that long G2 of pot1Δ rqh1-hd double mutant may allow time for the accumulation of recombination intermediates which disturb chromosome segregation and make cells sensitive to TBZ. - Ηighlights: • We show link between long G2 and accumulation of toxic recombination intermediates. • Accumulation of recombination intermediates at telomere results in TBZ sensitivity. • Activation of DNA damage checkpoint worsens cells' viability in presence of TBZ.« less

  20. Chromosome segregation regulation in human zygotes: altered mitotic histone phosphorylation dynamics underlying centromeric targeting of the chromosomal passenger complex.

    PubMed

    van de Werken, C; Avo Santos, M; Laven, J S E; Eleveld, C; Fauser, B C J M; Lens, S M A; Baart, E B

    2015-10-01

    Are the kinase feedback loops that regulate activation and centromeric targeting of the chromosomal passenger complex (CPC), functional during mitosis in human embryos? Investigation of the regulatory kinase pathways involved in centromeric CPC targeting revealed normal phosphorylation dynamics of histone H2A at T120 (H2ApT120) by Bub1 kinase and subsequent recruitment of Shugoshin, but phosphorylation of histone H3 at threonine 3 (H3pT3) by Haspin failed to show the expected centromeric enrichment on metaphase chromosomes in the zygote. Human cleavage stage embryos show high levels of chromosomal instability. What causes this high error rate is unknown, as mechanisms used to ensure proper chromosome segregation in mammalian embryos are poorly described. In this study, we investigated the pathways regulating CPC targeting to the inner centromere in human embryos. We characterized the distribution of the CPC in relation to activity of its two main centromeric targeting pathways: the Bub1-H2ApT120-Sgo-CPC and Haspin-H3pT3-CPC pathways. The study was conducted between May 2012 and March 2014 on human surplus embryos resulting from in vitro fertilization treatment and donated for research. In zygotes, nuclear envelope breakdown was monitored by time-lapse imaging to allow timed incubations with specific inhibitors to arrest at prometaphase and metaphase, and to interfere with Haspin and Aurora B/C kinase activity. Functionality of the targeting pathways was assessed through characterization of histone phosphorylation dynamics by immunofluorescent analysis, combined with gene expression by RT-qPCR and immunofluorescent localization of key pathway proteins. Immunofluorescent analysis of the CPC subunit Inner Centromere Protein revealed the pool of stably bound CPC proteins was not strictly confined to the inner centromere of prometaphase chromosomes in human zygotes, as observed in later stages of preimplantation development and somatic cells. Investigation of the

  1. Detection of chromosomal abnormalities, congenital abnormalities and transfusion syndrome in twins.

    PubMed

    Sperling, L; Kiil, C; Larsen, L U; Brocks, V; Wojdemann, K R; Qvist, I; Schwartz, M; Jørgensen, C; Espersen, G; Skajaa, K; Bang, J; Tabor, A

    2007-05-01

    To evaluate the outcome of screening for structural malformations in twins and the outcome of screening for twin-twin transfusion syndrome (TTTS) among monochorionic twins through a number of ultrasound scans from 12 weeks' gestation. Enrolled into this prospective multicenter observational study were women with twin pregnancies diagnosed before 14 + 6 gestational weeks. The monochorionic pregnancies were scanned every second week until 23 weeks in order to rule out early TTTS. All pregnancies had an anomaly scan in week 19 and fetal echocardiography in week 21 that was performed by specialists in fetal echocardiography. Zygosity was determined by DNA analysis in all twin pairs with the same sex. Among the 495 pregnancies the prenatal detection rate for severe structural abnormalities including chromosomal aneuploidies was 83% by the combination of a first-trimester nuchal translucency scan and the anomaly scan in week 19. The incidence of severe structural abnormalities was 2.6% and two-thirds of these anomalies were cardiac. There was no significant difference between the incidence in monozygotic and dizygotic twins, nor between twins conceived naturally or those conceived by assisted reproduction. The incidence of TTTS was 23% from 12 weeks until delivery, and all those monochorionic twin pregnancies that miscarried had signs of TTTS. Twin pregnancies have an increased risk of congenital malformations and one out of four monochorionic pregnancies develops TTTS. Ultrasound screening to assess chorionicity and follow-up of monochorionic pregnancies to detect signs of TTTS, as well as malformation screening, are therefore essential in the antenatal care of twin pregnancies. Copyright (c) 2007 ISUOG.

  2. Chromosomal aneuploidies and copy number variations in posterior fossa abnormalities diagnosed by prenatal ultrasonography.

    PubMed

    Lei, Ting; Feng, Jie-Ling; Xie, Ying-Jun; Xie, Hong-Ning; Zheng, Ju; Lin, Mei-Fang

    2017-11-01

    To explore the genetic aetiology of fetal posterior fossa abnormalities (PFAs). This study involved cases of PFAs that were identified by prenatal ultrasonographic screening and confirmed postnatally between January 2012 and January 2016. Conventional cytogenetic analyses and chromosomal microarray analysis were performed, and chromosomal aneuploidies and copy number variations (CNVs) were identified. Among 74 cases included in this study, 8 were of Blake's pouch cyst; 7, Dandy-Walker malformation; 11, vermian hypoplasia; 32, enlarged cisterna magna; and 16, cerebellar hypoplasia. The rates of nonbenign chromosomal aberrations (including chromosomal aneuploidies, pathogenic CNVs, and variants of unknown significance) were 2/8 (25.0%), 2/7 (28.5%), 8/11 (72.7%), 7/32 (21.9%), and 6/16 (37.5%), respectively. Cases were also classified as isolated PFAs (30/74), PFAs with other central nervous system (CNS) abnormalities (13/74), or PFAs with extra-CNS structural abnormalities (31/74). No fetuses with isolated PFAs or PFAs accompanied by other CNS abnormalities exhibited chromosomal aneuploidies or pathogenic CNVs. The rate of pathogenic chromosomal aberrations in the remaining fetuses was 17/31 (22.9%). The combined use of chromosomal microarray analysis and karyotype analysis might assist the prenatal diagnosis and management of PFAs, with extra-CNS structural abnormalities being detected by ultrasonography. © 2017 John Wiley & Sons, Ltd.

  3. X Chromosome Abnormalities and Cognitive Development: Implications for Understanding Normal Human Development.

    ERIC Educational Resources Information Center

    Walzer, Stanley

    1985-01-01

    Argues that knowledge from studies of individuals with sex chromosome abnormalities can further understanding of aspects of normal human development. Studies of XO girls, XXY boys, XXX girls, and males with a fragile X chromosome are summarized to demonstrate how results contribute to knowledge about normal cognitive development and about…

  4. Cyc17, a meiosis-specific cyclin, is essential for anaphase initiation and chromosome segregation in Tetrahymena thermophila.

    PubMed

    Yan, Guan-Xiong; Dang, Huai; Tian, Miao; Zhang, Jing; Shodhan, Anura; Ning, Ying-Zhi; Xiong, Jie; Miao, Wei

    2016-07-17

    Although the role of cyclins in controlling nuclear division is well established, their function in ciliate meiosis remains unknown. In ciliates, the cyclin family has undergone massive expansion which suggests that diverse cell cycle systems exist, and this warrants further investigation. A screen for cyclins in the model ciliate Tetrahymena thermophila showed that there are 34 cyclins in this organism. Only 1 cyclin, Cyc17, contains the complete cyclin core and is specifically expressed during meiosis. Deletion of CYC17 led to meiotic arrest at the diakinesis-like metaphase I stage. Expression of genes involved in DNA metabolism and chromosome organization (chromatin remodeling and basic chromosomal structure) was repressed in cyc17 knockout matings. Further investigation suggested that Cyc17 is involved in regulating spindle pole attachment, and is thus essential for chromosome segregation at meiosis. These findings suggest a simple model in which chromosome segregation is influenced by Cyc17.

  5. Association of recurrent pregnancy loss with chromosomal abnormalities and hereditary thrombophilias.

    PubMed

    Ocak, Z; Özlü, T; Ozyurt, O

    2013-06-01

    Recurrent pregnancy loss (RPL) which is generally known as >3 consecutive pregnancy losses before 20 weeks' gestation is seen in 0.5-2% of women. To evaluate the association of parental and fetal chromosomal abnormalities with recurrent pregnancy loss in our area and to analyze the frequency of three types of hereditary thrombophilia's; (MTHFR C677T polymorphisms, FV Leiden G1691A mutation and Prothrombin (factor II) G20210A mutation) in these female patients. The present case-control retrospective study was performed between February 2007 and December 2011 on 495 couples, who had two or more consecutive pregnancy losses before 20 weeks' gestation. We used conventional cytogenetic analysis and polymerase chain reaction-restriction fragment length polymorphism. Parental chromosomal abnormality was detected in 28 cases (2.8% of all cases, 5.7% of the couples) most of which (92.9%) were structural abnormalities. All of the structural abnormalities were balanced chromosomal translocations. Chromosomal analysis performed from the abortion materials detected a major chromosomal abnormality in 31.9% of the cases. The most frequently observed alteration in the hereditary thrombophilia genes was heterozygote mutation for the MTHFR C677T polymorphisms (n=55). Balanced translocations are the most commonly detected chromosomal abnormalities in couples being evaluated for recurrent pregnancy loss and these patients are the best candidates for offering prenatal genetic diagnosis by the help of which there is a possibility of obtaining a better reproductive outcome.

  6. Centromere proteins CENP-C and CAL1 functionally interact in meiosis for centromere clustering, pairing, and chromosome segregation.

    PubMed

    Unhavaithaya, Yingdee; Orr-Weaver, Terry L

    2013-12-03

    Meiotic chromosome segregation involves pairing and segregation of homologous chromosomes in the first division and segregation of sister chromatids in the second division. Although it is known that the centromere and kinetochore are responsible for chromosome movement in meiosis as in mitosis, potential specialized meiotic functions are being uncovered. Centromere pairing early in meiosis I, even between nonhomologous chromosomes, and clustering of centromeres can promote proper homolog associations in meiosis I in yeast, plants, and Drosophila. It was not known, however, whether centromere proteins are required for this clustering. We exploited Drosophila mutants for the centromere proteins centromere protein-C (CENP-C) and chromosome alignment 1 (CAL1) to demonstrate that a functional centromere is needed for centromere clustering and pairing. The cenp-C and cal1 mutations result in C-terminal truncations, removing the domains through which these two proteins interact. The mutants show striking genetic interactions, failing to complement as double heterozygotes, resulting in disrupted centromere clustering and meiotic nondisjunction. The cluster of meiotic centromeres localizes to the nucleolus, and this association requires centromere function. In Drosophila, synaptonemal complex (SC) formation can initiate from the centromere, and the SC is retained at the centromere after it disassembles from the chromosome arms. Although functional CENP-C and CAL1 are dispensable for assembly of the SC, they are required for subsequent retention of the SC at the centromere. These results show that integral centromere proteins are required for nuclear position and intercentromere associations in meiosis.

  7. Next generation sequencing identifies abnormal Y chromosome and candidate causal variants in premature ovarian failure patients.

    PubMed

    Lee, Yujung; Kim, Changshin; Park, YoungJoon; Pyun, Jung-A; Kwack, KyuBum

    2016-12-01

    Premature ovarian failure (POF) is characterized by heterogeneous genetic causes such as chromosomal abnormalities and variants in causal genes. Recently, development of techniques made next generation sequencing (NGS) possible to detect genome wide variants including chromosomal abnormalities. Among 37 Korean POF patients, XY karyotype with distal part deletions of Y chromosome, Yp11.32-31 and Yp12 end part, was observed in two patients through NGS. Six deleterious variants in POF genes were also detected which might explain the pathogenesis of POF with abnormalities in the sex chromosomes. Additionally, the two POF patients had no mutation in SRY but three non-synonymous variants were detected in genes regarding sex reversal. These findings suggest candidate causes of POF and sex reversal and show the propriety of NGS to approach the heterogeneous pathogenesis of POF. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Assessment of chromosomal abnormalities in sperm of infertile men using sperm karyotyping and multicolour fluorescence in situ hybridization (FISH)

    SciTech Connect

    Moosani, N.; Martin, R.H.

    1994-09-01

    Individuals with male factor infertility resulting from idiopathic oligo-, astheno- or teratozoospermia are frequently offered IVF in an attempt to increase their chances of having a child. A concern remains whether these infertile males have an elevated risk of transmitting chromosomal abnormalities to their offspring. Sperm chromosomal complements from these men were assayed using the human sperm/hamster oocyte fusion system and fluorescence in situ hybridization (FISH) on sperm nuclei. For each of 5 infertile patients, 100 sperm karyotypes were analyzed and multicolour FISH analysis was performed on a minimum of 10,000 sperm nuclei for each chromosome-specific DNA probe for chromosomesmore » 1 (pUC1.77), 12 (D12Z3), X (XC) and Y (DYZ3). As a group, the infertile patients showed increased frequencies of both numerical ({chi}{sup 2}=17.26, {proportional_to} <0.001) and total abnormalities ({chi}{sup 2}=7.78, {proportional_to} <0.01) relative to control donors when assessed by sperm karyotypes. Analysis of sperm nuclei by FISH indicated a significant increase in the frequency of disomy for chromosome 1 in three of the five patients as compared to control donors ({chi}{sup 2}>8.35, {proportional_to} <0.005). In addition, the frequency of XY disomy was significantly higher in four of the five patients studied by FISH ({chi}{sup 2}>10.58, {proportional_to}<0.005), suggesting that mis-segregation caused by the failure of the XY bivalent to pair may play a role in idiopathic male infertility.« less

  9. Characterization and prognostic implication of 17 chromosome abnormalities in myelodysplastic syndrome.

    PubMed

    Sánchez-Castro, Judit; Marco-Betés, Víctor; Gómez-Arbonés, Xavier; Arenillas, Leonor; Valcarcel, David; Vallespí, Teresa; Costa, Dolors; Nomdedeu, Benet; Jimenez, María José; Granada, Isabel; Grau, Javier; Ardanaz, María T; de la Serna, Javier; Carbonell, Félix; Cervera, José; Sierra, Adriana; Luño, Elisa; Cervero, Carlos J; Falantes, José; Calasanz, María J; González-Porrás, José R; Bailén, Alicia; Amigo, M Luz; Sanz, Guillermo; Solé, Francesc

    2013-07-01

    The prognosis of chromosome 17 (chr17) abnormalities in patients with primary myelodysplastic syndrome (MDS) remains unclear. The revised International Prognostic Scoring System (IPSS-R) includes these abnormalities within the intermediate cytogenetic risk group. This study assessed the impact on overall survival (OS) and risk of acute myeloid leukemia transformation (AMLt) of chr17 abnormalities in 88 patients with primary MDS. We have compared this group with 1346 patients with primary MDS and abnormal karyotype without chr17 involved. The alterations of chr17 should be considered within group of poor prognosis. The different types of alterations of chromosome 17 behave different prognosis. The study confirms the intermediate prognostic impact of the i(17q), as stated in IPSS-R. The results of the study, however, provide valuable new information on the prognostic impact of alterations of chromosome 17 in complex karyotypes. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Phospho-Bcl-xL(Ser62) influences spindle assembly and chromosome segregation during mitosis.

    PubMed

    Wang, Jianfang; Beauchemin, Myriam; Bertrand, Richard

    2014-01-01

    Functional analysis of a series of phosphorylation mutants reveals that Bcl-xL(Ser62Ala) influences cell entry into anaphase and mitotic exit in taxol-exposed cells compared with cells expressing wild-type Bcl-xL or a series of other phosphorylation mutants, an effect that appears to be independent of its anti-apoptotic activity. During normal mitosis progression, Bcl-xL(Ser62) is strongly phosphorylated by PLK1 and MAPK14/SAPKp38α at the prometaphase, metaphase, and the anaphase boundaries, while it is de-phosphorylated at telophase and cytokinesis. Phospho-Bcl-xL(Ser62) localizes in centrosomes with γ-tubulin and in the mitotic cytosol with some spindle-assembly checkpoint signaling components, including PLK1, BubR1, and Mad2. In taxol- and nocodazole-exposed cells, phospho-Bcl-xL(Ser62) also binds to Cdc20- Mad2-, BubR1-, and Bub3-bound complexes, while Bcl-xL(Ser62Ala) does not. Silencing Bcl-xL expression and expressing the phosphorylation mutant Bcl-xL(Ser62Ala) lead to an increased number of cells harboring mitotic spindle defects including multipolar spindle, chromosome lagging and bridging, aneuploidy with micro-, bi-, or multi-nucleated cells, and cells that fail to resolve undergo mitosis within 6 h. Together, the data indicate that during mitosis, Bcl-xL(Ser62) phosphorylation impacts on spindle assembly and chromosome segregation, influencing chromosome stability. Observations of mitotic cells harboring aneuploidy with micro-, bi-, or multi-nucleated cells, and cells that fail to resolve undergo mitosis within 6 h were also made with cells expressing the phosphorylation mutant Bcl-xL(Ser49Ala) and dual mutant Bcl-xL(Ser49/62Ala).

  11. Hidden chromosome 8 abnormalities detected by FISH in adult primary myelodysplastic syndromes.

    PubMed

    Panani, Anna D; Pappa, Vasiliki

    2005-01-01

    Acquired clonal chromosomal abnormalities are found in about 30-50% of primary myelodysplastic syndromes (MDS). These abnormalities are predominantly characterized by total/partial chromosomal losses or gains and rarely by balanced structural aberrations. Trisomy 8 represents the most common chromosomal gain. In the present study, the numerical aberration of chromosome 8 was evaluated by the fluorescence in situ hybridization (FISH) technique in MDS, and the results compared with those of conventional cytogenetics. Thirty adult patients with primary MDS, 17 with a normal karyotype and 13 with several chromosomal abnormalities except chromosome 8, were included in this study. On comparing the results of FISH and conventional cytogenetics, a superiority of FISH over the karyotype was detected in 3 cases. In one of them, further cytogenetic analysis confirmed the FISH results. Nevertheless, the FISH technique has limitations, detecting only abnormalities specific for the target FISH probe used In clinical practice, conventional cytogenetics continues to be the basic technique for MDS patient evaluation. However, a large number of metaphases, even those of poor quality, must be analyzed in each case. The FISH technique could be considered to be complementary to achieve a more accurate analysis.

  12. The incidence of chromosome abnormalities in neonates with structural heart disease.

    PubMed

    Dykes, John C; Al-mousily, Mohammad F; Abuchaibe, Eda-Cristina; Silva, Jennifer N; Zadinsky, Jennifer; Duarte, Daniel; Welch, Elizabeth

    2016-04-01

    This study was conducted to determine the prevalence of chromosomal anomalies in newborns with structural heart disease admitted to the cardiac intensive care unit (CICU) at Nicklaus Children's Hospital (NCH). A retrospective review identified newborns age 30 days or less admitted to NCH CICU between 2004 and 2010. Patients with structural heart disease who required admission to our CICU and received karyotype or karyotype and fluorescent in situ hybridization (FISH) testing were included in the study. All patients were examined for the presence of dysmorphic features. Four hundred and eighty-two patients met the criteria for the study; 405 (84%) received both karyotype and FISH. Chromosome abnormalities were present in 86 (17.8%) patients. Syndromes accounted for 20 (5.1%) of those with normal chromosomes. Dysmorphic features were seen in 79.1% of patients with abnormal chromosomes and 25.5% of those with normal chromosomes. All patients with syndromes were dysmorphic. Race and gender did not significantly affect the incidence of genetic abnormalities. Chromosome abnormalities, including syndromes, are prevalent in newborns with congenital heart disease. Further research is needed to evaluate the utility of cytogenetic screening in all children with congenital heart disease. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  13. Abnormalities at chromosome region 3p12-14 characterize clear cell renal carcinoma.

    PubMed

    Carroll, P R; Murty, V V; Reuter, V; Jhanwar, S; Fair, W R; Whitmore, W F; Chaganti, R S

    1987-06-01

    In an effort to determine whether or not any characteristic chromosomal abnormalities exist in renal cancer, cytogenetic findings were correlated with tumor histology in nine cases of renal adenocarcinoma. Metaphase preparations adequate for analysis were obtained from cultures harvested between day 3 and day 21. Model chromosome number was diploid in three cases, hypodiploid in three, and hyperdiploid in the remaining three. One clear cell adenocarcinoma failed to reveal any chromosomal abnormality. Two tumors, a tubular/papillary carcinoma and an acinar/papillary carcinoma, showed the clonal abnormalities del(1)(p2l),+2,+7,+8,+12,+13,+16,+17,-21 and t(2;10)(q14-21;q26),+7q,+11q,-18, respectively. Interestingly, five of six clear cell tumors studied had clonal abnormalities affecting the short arm of chromosome #3 in the 3p12-21 region, and in the remaining case, of 15 karyotyped metaphases suitable for interpretation, one showed a deletion in 3p. These data indicate that clear cell carcinoma of the kidney may be associated with a nonrandom chromosomal abnormality involving the 3p12-14 region.

  14. Detection of chromosomal abnormalities and the 22q11 microdeletion in fetuses with congenital heart defects.

    PubMed

    Lv, Wei; Wang, Shuyu

    2014-11-01

    Chromosomal abnormalities and the 22q11 microdeletion are implicated in congenital heart defects (CHDs). This study was designed to detect these abnormalities in fetuses and determine the effect of genetic factors on CHD etiology. Between January 2010 and December 2011, 113 fetuses with CHD treated at the Beijing Obstetrics and Gynecology Hospital were investigated, using chromosome karyotyping of either amniotic fluid cell or umbilical cord blood cell samples. Fetuses with a normal result were then investigated for the 22q11 microdeletion by fluorescence in situ hybridization. Of the 113 patients, 12 (10.6%) exhibited chromosomal abnormalities, while 6 (5.3%) of the remaining 101 cases presented with a 22q11 microdeletion. The incidence of chromosomal abnormalities was significantly higher in the group of fetuses presenting with extracardiac malformations in addition to CHD (P<0.001), although the detection of the 22q11 microdeletion was not significantly different between the two groups (P=0.583). In addition, all fetuses with the 22q11 microdeletion occurred de novo. In conclusion, genetic factors are important in the etiology of CHD. Where fetuses present with cardiac defects, additional chromosomal analysis is required to detect extracardiac abnormalities. Fetuses with heart defects should also be considered for 22q11 microdeletion detection to evaluate fetal prognosis, particularly prior to surgery.

  15. Abnormal chromosome complement resulting from a familial inversion of chromosome 2.

    PubMed Central

    Richter, S; Lockwood, B; Lockwood, D; Allanson, J

    1989-01-01

    It has been suggested that pericentric inversions of chromosome 2 increase the risk for spontaneous abortion but do not increase the risk for unbalanced recombinant offspring. We report our experience of a familial pericentric inversion of chromosome 2 resulting in two unbalanced recombinant offspring. Both subjects have 46,XX,rec(2),dup q,inv(2)(p25q35). Images PMID:2479747

  16. Frequency of chromosome healing and interstitial telomeres in 40 cases of constitutional abnormalities.

    PubMed

    Fortin, F; Beaulieu Bergeron, M; Fetni, R; Lemieux, N

    2009-01-01

    Human telomeres play a major role in stabilizing chromosome ends and preventing fusions. Chromosomes bearing a broken end are rescued by the acquisition of a new telomeric cap without any subtelomeric sequences being present at the breakpoint, a process referred to as chromosome healing. Conversely, a loss of telomeric function or integrity can lead to the presence of interstitial telomeres at the junction site in translocations or ring chromosomes. In order to determine the frequency at which interstitial telomeres or chromosome healing events are observed in target chromosome abnormalities, we conducted a retrospective FISH study using pan-telomeric and chromosome-specific subtelomeric probes on archival material from 40 cases of terminal deletions, translocations or ring chromosomes. Of the 19 terminal deletions investigated, 17 were negative for the subtelomeric probe specific to the deleted arm despite being positive for the pan-telomeric probe. These 17 cases were thus considered as having been rescued through chromosome healing, suggesting that this process is frequent in terminal deletions. In addition, as 2 of these cases were inherited from a parent bearing the same deletion, chromosomes healed by this process are thus stable through mitosis and meiosis. Regarding the 13 cases of translocations and 8 ring chromosomes, 4 and 2 cases respectively demonstrated pan-telomeric sequences at the interstitial junction point. Furthermore, 2 cases of translocations and 1 ring chromosome had both interstitial pan-telomeres and subtelomeres, whereas 2 other cases of ring chromosomes and 1 case of translocation only showed interstitial subtelomeres. Therefore, interstitial (sub)telomeric sequences in translocations and ring chromosomes are more common than previously thought, as we found a frequency of 43% in this study. Moreover, our results illustrate the necessity of performing FISH with both subtelomeric and pan-telomeric probes when investigating these

  17. Alterations and Abnormal Mitosis of Wheat Chromosomes Induced by Wheat-Rye Monosomic Addition Lines

    PubMed Central

    Fu, Shulan; Yang, Manyu; Fei, Yunyan; Tan, Feiquan; Ren, Zhenglong; Yan, Benju; Zhang, Huaiyu; Tang, Zongxiang

    2013-01-01

    Background Wheat-rye addition lines are an old topic. However, the alterations and abnormal mitotic behaviours of wheat chromosomes caused by wheat-rye monosomic addition lines are seldom reported. Methodology/Principal Findings Octoploid triticale was derived from common wheat T. aestivum L. ‘Mianyang11’×rye S. cereale L. ‘Kustro’ and some progeny were obtained by the controlled backcrossing of triticale with ‘Mianyang11’ followed by self-fertilization. Genomic in situ hybridization (GISH) using rye genomic DNA and fluorescence in situ hybridization (FISH) using repetitive sequences pAs1 and pSc119.2 as probes were used to analyze the mitotic chromosomes of these progeny. Strong pSc119.2 FISH signals could be observed at the telomeric regions of 3DS arms in ‘Mianyang11’. However, the pSc119.2 FISH signals were disappeared from the selfed progeny of 4R monosomic addition line and the changed 3D chromosomes could be transmitted to next generation stably. In one of the selfed progeny of 7R monosomic addition line, one 2D chromosome was broken and three 4A chromosomes were observed. In the selfed progeny of 6R monosomic addition line, structural variation and abnormal mitotic behaviour of 3D chromosome were detected. Additionally, 1A and 4B chromosomes were eliminated from some of the progeny of 6R monosomic addition line. Conclusions/Significance These results indicated that single rye chromosome added to wheat might cause alterations and abnormal mitotic behaviours of wheat chromosomes and it is possible that the stress caused by single alien chromosome might be one of the factors that induced karyotype alteration of wheat. PMID:23936213

  18. Artificial Neural Network for the Prediction of Chromosomal Abnormalities in Azoospermic Males.

    PubMed

    Akinsal, Emre Can; Haznedar, Bulent; Baydilli, Numan; Kalinli, Adem; Ozturk, Ahmet; Ekmekçioğlu, Oğuz

    2018-02-04

    To evaluate whether an artifical neural network helps to diagnose any chromosomal abnormalities in azoospermic males. The data of azoospermic males attending to a tertiary academic referral center were evaluated retrospectively. Height, total testicular volume, follicle stimulating hormone, luteinising hormone, total testosterone and ejaculate volume of the patients were used for the analyses. In artificial neural network, the data of 310 azoospermics were used as the education and 115 as the test set. Logistic regression analyses and discriminant analyses were performed for statistical analyses. The tests were re-analysed with a neural network. Both logistic regression analyses and artificial neural network predicted the presence or absence of chromosomal abnormalities with more than 95% accuracy. The use of artificial neural network model has yielded satisfactory results in terms of distinguishing patients whether they have any chromosomal abnormality or not.

  19. Naturally Occurring Differences in CENH3 Affect Chromosome Segregation in Zygotic Mitosis of Hybrids

    PubMed Central

    Maheshwari, Shamoni; Tan, Ek Han; West, Allan; Franklin, F. Chris H.; Comai, Luca

    2015-01-01

    The point of attachment of spindle microtubules to metaphase chromosomes is known as the centromere. Plant and animal centromeres are epigenetically specified by a centromere-specific variant of Histone H3, CENH3 (a.k.a. CENP-A). Unlike canonical histones that are invariant, CENH3 proteins are accumulating substitutions at an accelerated rate. This diversification of CENH3 is a conundrum since its role as the key determinant of centromere identity remains a constant across species. Here, we ask whether naturally occurring divergence in CENH3 has functional consequences. We performed functional complementation assays on cenh3-1, a null mutation in Arabidopsis thaliana, using untagged CENH3s from increasingly distant relatives. Contrary to previous results using GFP-tagged CENH3, we find that the essential functions of CENH3 are conserved across a broad evolutionary landscape. CENH3 from a species as distant as the monocot Zea mays can functionally replace A. thaliana CENH3. Plants expressing variant CENH3s that are fertile when selfed show dramatic segregation errors when crossed to a wild-type individual. The progeny of this cross include hybrid diploids, aneuploids with novel genetic rearrangements and haploids that inherit only the genome of the wild-type parent. Importantly, it is always chromosomes from the plant expressing the divergent CENH3 that missegregate. Using chimeras, we show that it is divergence in the fast-evolving N-terminal tail of CENH3 that is causing segregation errors and genome elimination. Furthermore, we analyzed N-terminal tail sequences from plant CENH3s and discovered a modular pattern of sequence conservation. From this we hypothesize that while the essential functions of CENH3 are largely conserved, the N-terminal tail is evolving to adapt to lineage-specific centromeric constraints. Our results demonstrate that this lineage-specific evolution of CENH3 causes inviability and sterility of progeny in crosses, at the same time producing

  20. Women's experiences receiving abnormal prenatal chromosomal microarray testing results.

    PubMed

    Bernhardt, Barbara A; Soucier, Danielle; Hanson, Karen; Savage, Melissa S; Jackson, Laird; Wapner, Ronald J

    2013-02-01

    Genomic microarrays can detect copy-number variants not detectable by conventional cytogenetics. This technology is diffusing rapidly into prenatal settings even though the clinical implications of many copy-number variants are currently unknown. We conducted a qualitative pilot study to explore the experiences of women receiving abnormal results from prenatal microarray testing performed in a research setting. Participants were a subset of women participating in a multicenter prospective study "Prenatal Cytogenetic Diagnosis by Array-based Copy Number Analysis." Telephone interviews were conducted with 23 women receiving abnormal prenatal microarray results. We found that five key elements dominated the experiences of women who had received abnormal prenatal microarray results: an offer too good to pass up, blindsided by the results, uncertainty and unquantifiable risks, need for support, and toxic knowledge. As prenatal microarray testing is increasingly used, uncertain findings will be common, resulting in greater need for careful pre- and posttest counseling, and more education of and resources for providers so they can adequately support the women who are undergoing testing.

  1. The influence of parity and gravidity on first trimester markers of chromosomal abnormality.

    PubMed

    Spencer, K; Ong, C Y; Liao, A W; Nicolaides, K H

    2000-10-01

    We have studied changes in first trimester fetal nuchal translucency (NT) and maternal serum free beta-hCG and PAPP-A with gravidity and parity in 3252 singleton pregnancies unaffected by chromosomal abnormality or major pregnancy complications. We have shown that gravidity and parity is associated with a small but progressive decrease in fetal NT and a small but progressive increase in free beta-hCG and PAPP-A. None of these small changes with increasing gravidity or parity are statistically significant and hence correction for these variables is not necessary when considering first trimester screening for chromosomal abnormalities. Copyright 2000 John Wiley & Sons, Ltd.

  2. CAFE: an R package for the detection of gross chromosomal abnormalities from gene expression microarray data.

    PubMed

    Bollen, Sander; Leddin, Mathias; Andrade-Navarro, Miguel A; Mah, Nancy

    2014-05-15

    The current methods available to detect chromosomal abnormalities from DNA microarray expression data are cumbersome and inflexible. CAFE has been developed to alleviate these issues. It is implemented as an R package that analyzes Affymetrix *.CEL files and comes with flexible plotting functions, easing visualization of chromosomal abnormalities. CAFE is available from https://bitbucket.org/cob87icW6z/cafe/ as both source and compiled packages for Linux and Windows. It is released under the GPL version 3 license. CAFE will also be freely available from Bioconductor. sander.h.bollen@gmail.com or nancy.mah@mdc-berlin.de Supplementary data are available at Bioinformatics online.

  3. Is there an association with constitutional structural chromosomal abnormalities and hematologic neoplastic process? A short review.

    PubMed

    Panani, Anna D

    2009-04-01

    The occasional observation of constitutional chromosomal abnormalities in patients with a malignant disease has led to a number of studies on their potential role in cancer development. Investigations of families with hereditary cancers and constitutional chromosomal abnormalities have been key observations leading to the molecular identification of specific genes implicated in tumorigenesis. Large studies have been reported on the incidence of constitutional chromosomal aberrations in patients with hematologic malignancies, but they could not confirm an increased risk for hematologic malignancy among carriers of structural chromosomal changes. However, it is of particular interest that constitutional structural aberrations with breakpoints similar to leukemia-associated specific breakpoints have been reported in patients with hematologic malignancies. Because of insufficient data, it remains still unclear if these aberrations represent random events or are associated with malignancy. There has been a substantial discussion about mechanisms involved in constitutional structural chromosomal changes in the literature. The documentation of more patients with constitutional structural chromosomal changes could be of major importance. Most importantly, the molecular investigation of chromosomal regions involved in rearrangements could give useful information on the genetic events underlying constitutional anomalies, contributing to isolation of genes important in the development of the neoplastic process. Regarding constitutional anomalies in patients with hematologic disorders, a survey of the cytogenetic data of our cytogenetics unit is herein also presented.

  4. Method of detecting genetic translocations identified with chromosomal abnormalities

    DOEpatents

    Gray, Joe W.; Pinkel, Daniel; Tkachuk, Douglas

    2001-01-01

    Methods and compositions for staining based upon nucleic acid sequence that employ nucleic acid probes are provided. Said methods produce staining patterns that can be tailored for specific cytogenetic analyses. Said probes are appropriate for in situ hybridization and stain both interphase and metaphase chromosomal material with reliable signals. The nucleic acid probes are typically of a complexity greater than 50 kb, the complexity depending upon the cytogenetic application. Methods and reagents are provided for the detection of genetic rearrangements. Probes and test kits are provided for use in detecting genetic rearrangements, particularly for use in tumor cytogenetics, in the detection of disease related loci, specifically cancer, such as chronic myelogenous leukemia (CML) and for biological dosimetry. Methods and reagents are described for cytogenetic research, for the differentiation of cytogenetically similar but genetically different diseases, and for many prognostic and diagnostic applications.

  5. Method of detecting genetic deletions identified with chromosomal abnormalities

    DOEpatents

    Gray, Joe W; Pinkel, Daniel; Tkachuk, Douglas

    2013-11-26

    Methods and compositions for staining based upon nucleic acid sequence that employ nucleic acid probes are provided. Said methods produce staining patterns that can be tailored for specific cytogenetic analyzes. Said probes are appropriate for in situ hybridization and stain both interphase and metaphase chromosomal material with reliable signals. The nucleic acids probes are typically of a complexity greater tha 50 kb, the complexity depending upon the cytogenetic application. Methods and reagents are provided for the detection of genetic rearrangements. Probes and test kits are provided for use in detecting genetic rearrangements, particlularly for use in tumor cytogenetics, in the detection of disease related loci, specifically cancer, such as chronic myelogenous leukemia (CML) and for biological dosimetry. Methods and reagents are described for cytogenetic research, for the differentiation of cytogenetically similar ut genetically different diseases, and for many prognostic and diagnostic applications.

  6. Traditional karyotyping vs copy number variation sequencing for detection of chromosomal abnormalities associated with spontaneous miscarriage.

    PubMed

    Liu, S; Song, L; Cram, D S; Xiong, L; Wang, K; Wu, R; Liu, J; Deng, K; Jia, B; Zhong, M; Yang, F

    2015-10-01

    To compare the performance of traditional G-banding karyotyping with that of copy number variation sequencing (CNV-Seq) for detection of chromosomal abnormalities associated with miscarriage. Products of conception (POC) were collected from spontaneous miscarriages. Chromosomal abnormalities were detected using high-resolution G-banding karyotyping and CNV sequencing. Quantitative fluorescent polymerase chain reaction analysis of maternal and POC DNA for short tandem repeat (STR) markers was used to both monitor maternal cell contamination and confirm the chromosomal status and sex of the miscarriage tissue. A total of 64 samples of POC, comprising 16 with an abnormal and 48 with a normal karyotype, were selected and coded for analysis by CNV-Seq. CNV-Seq results were concordant for 14 (87.5%) of the 16 gross chromosomal abnormalities identified by karyotyping, including 11 autosomal trisomies and three sex chromosomal aneuploidies (45,X). Of the two discordant results, a 69,XXX polyploidy was missed by CNV-Seq, although supporting STR marker analysis confirmed the triploidy. In contrast, CNV-Seq identified a sample with 45,X karyotype as a 45,X/46,XY mosaic. In the remaining 48 samples of POC with a normal karyotype, CNV-Seq detected a 2.58-Mb 22q deletion associated with DiGeorge syndrome and nine different smaller CNVs of no apparent clinical significance. CNV-Seq used in parallel with STR profiling is a reliable and accurate alternative to karyotyping for identifying chromosome copy number abnormalities associated with spontaneous miscarriage. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

  7. High frequency of X chromosome abnormalities in women with short stature and elevated liver enzymes.

    PubMed

    Roulot, Dominique; Malan, Valérie; Ziol, Marianne; Linglart, Agnès; Bourcier, Valérie; Beaugrand, Michel; Benzacken, Brigitte

    2014-08-01

    Paucisymptomatic forms of Turner's syndrome (TS), in which short stature is the predominant clinical abnormality, remain underdiagnosed. Abnormal liver tests are extremely frequent in adult TS patients reflecting various types of hepatic lesions. The objective of the study was to investigate whether unexplained elevated liver enzymes in women with short stature could reveal X chromosome abnormalities of undiagnosed TS. Thirty-one consecutive short stature women displaying elevated liver enzymes and no previous diagnosis of TS were compared with 31 age-matched controls in a prospective study. Liver biopsy was performed in 26 patients. Systematic karyotype analysis and fluorescence in situ hybridization. X chromosome abnormalities were found in 27 patients and one control (87.0% vs 3.2%, P < .0001), including a 45,X/46,XX mosaicism in 24 patients and isochromosome of the long arm in three. Liver histological analysis showed architectural changes in 17 patients with nodular regenerative hyperplasia in 12. Biliary lesions were present in 13 patients and liver steatosis in 20. X chromosome abnormalities indicative of cryptic TS are extremely frequent in short-stature women with unexplained elevated liver enzymes. In short-stature women, abnormal liver tests should lead to systematic karyotype analysis.

  8. Constitutional abnormalities of chromosome 21 predispose to iAMP21-acute lymphoblastic leukaemia.

    PubMed

    Harrison, Christine J; Schwab, Claire

    2016-03-01

    In addition to Down syndrome, individuals with other constitutional abnormalities of chromosome 21 have an increased risk of developing childhood acute lymphoblastic leukaemia (ALL). Specifically, carriers of the Robertsonian translocation between chromosomes 15 and 21, rob(15;21) (q10; q10)c, have ∼2,700 increased risk of developing ALL with iAMP21 (intrachromosomal amplification of chromosome 21). In these patients, chromosome 15 as well as chromosome 21 is involved in the formation of iAMP21, referred to here as der(21)(15;21). Individuals with constitutional ring chromosomes involving chromosome 21, r(21)c, are also predisposed to iAMP21-ALL, involving the same series of mutational processes as seen in sporadic- and der(21)(15;21)-iAMP21 ALL. Evidence is accumulating that the dicentric nature of the Robertsonian and ring chromosome is the initiating factor in the formation of the complex iAMP21 structure. Unravelling these intriguing predispositions to iAMP21-ALL may provide insight into how other complex rearrangements arise in cancer. Copyright © 2016. Published by Elsevier Masson SAS.

  9. Syndromes and constitutional chromosomal abnormalities associated with Wilms tumour

    PubMed Central

    Scott, R H; Stiller, C A; Walker, L; Rahman, N

    2006-01-01

    Wilms tumour has been reported in association with over 50 different clinical conditions and several abnormal constitutional karyotypes. Conclusive evidence of an increased risk of Wilms tumour exists for only a minority of these conditions, including WT1 associated syndromes, familial Wilms tumour, and certain overgrowth conditions such as Beckwith‐Wiedemann syndrome. In many reported conditions the rare co‐occurrence of Wilms tumour is probably due to chance. However, for several conditions the available evidence cannot either confirm or exclude an increased risk, usually because of the rarity of the syndrome. In addition, emerging evidence suggests that an increased risk of Wilms tumour occurs only in a subset of individuals for some syndromes. The complex clinical and molecular heterogeneity of disorders associated with Wilms tumour, together with the apparent absence of functional links between most of the known predisposition genes, suggests that abrogation of a variety of pathways can promote Wilms tumorigenesis. PMID:16690728

  10. Health-related quality of life experienced by children with chromosomal abnormalities and congenital heart defects.

    PubMed

    Garcia Guerra, Gonzalo; Joffe, Ari R; Robertson, Charlene M T; Atallah, Joseph; Alton, Gwen; Sauve, Reg S; Dinu, Irina A; Ross, David B; Rebeyka, Ivan M

    2014-03-01

    Long-term outcomes are fundamental in advising parents about the potential future of their children with congenital heart disease (CHD). No published reports have described the health-related quality of life (HRQL) experienced by children with chromosomal abnormalities who had surgery in early infancy for CHD. A study was undertaken to assess HRQL among children with chromosomal abnormalities and CHD. The authors hypothesized that these children have a worse HRQL than healthy children or a cohort of children matched for CHD diagnosis. Infants with chromosomal abnormalities undergoing cardiac surgery for CHD at 6 weeks of age or younger at the Stollery Children's Hospital between July 2000 and June 2005 were included in the study. The HRQL of these infants was assessed using the Pediatric Quality of Life Inventory (PedsQL) 4.0 Generic Core Scales completed by their parents at a 4-year follow-up evaluation. The study compared the scores for 16 children with normative data. The children with chromosomal abnormalities and CHD had significantly lower mean total PedsQL (71.3 vs. 87.3; p < 0.0001), Psychosocial Summary (70.3 vs. 86.1; p < 0.0001), and Physical Summary (74.3 vs. 89.2; p = 0.0006) scores. Compared with the matched children, those with chromosomal abnormalities had a significantly lower median total PedsQL (75.0 vs. 84.6; p = 0.03), Physical Summary (79.5 vs. 96.9; p = 0.007), and School Functioning (68.5 vs. 83.0; p = 0.03) scores. A better understanding of the mechanisms and determinants of HRQL in these children has the potential to yield important implications for clinical practice including clarity for treatment decision making as well as determination of targeted supports and services to meet the needs of these children and their families differentially.

  11. ParA and ParB coordinate chromosome segregation with cell elongation and division during Streptomyces sporulation

    PubMed Central

    Donczew, Magdalena; Mackiewicz, Paweł; Wróbel, Agnieszka; Flärdh, Klas; Zakrzewska-Czerwińska, Jolanta

    2016-01-01

    In unicellular bacteria, the ParA and ParB proteins segregate chromosomes and coordinate this process with cell division and chromosome replication. During sporulation of mycelial Streptomyces, ParA and ParB uniformly distribute multiple chromosomes along the filamentous sporogenic hyphal compartment, which then differentiates into a chain of unigenomic spores. However, chromosome segregation must be coordinated with cell elongation and multiple divisions. Here, we addressed the question of whether ParA and ParB are involved in the synchronization of cell-cycle processes during sporulation in Streptomyces. To answer this question, we used time-lapse microscopy, which allows the monitoring of growth and division of single sporogenic hyphae. We showed that sporogenic hyphae stop extending at the time of ParA accumulation and Z-ring formation. We demonstrated that both ParA and ParB affect the rate of hyphal extension. Additionally, we showed that ParA promotes the formation of massive nucleoprotein complexes by ParB. We also showed that FtsZ ring assembly is affected by the ParB protein and/or unsegregated DNA. Our results indicate the existence of a checkpoint between the extension and septation of sporogenic hyphae that involves the ParA and ParB proteins. PMID:27248800

  12. Alzheimer Abeta peptide induces chromosome mis-segregation and aneuploidy, including trisomy 21: requirement for tau and APP.

    PubMed

    Granic, Antoneta; Padmanabhan, Jaya; Norden, Michelle; Potter, Huntington

    2010-02-15

    Both sporadic and familial Alzheimer's disease (AD) patients exhibit increased chromosome aneuploidy, particularly trisomy 21, in neurons and other cells. Significantly, trisomy 21/Down syndrome patients develop early onset AD pathology. We investigated the mechanism underlying mosaic chromosome aneuploidy in AD and report that FAD mutations in the Alzheimer Amyloid Precursor Protein gene, APP, induce chromosome mis-segregation and aneuploidy in transgenic mice and in transfected cells. Furthermore, adding synthetic Abeta peptide, the pathogenic product of APP, to cultured cells causes rapid and robust chromosome mis-segregation leading to aneuploid, including trisomy 21, daughters, which is prevented by LiCl addition or Ca(2+) chelation and is replicated in tau KO cells, implicating GSK-3beta, calpain, and Tau-dependent microtubule transport in the aneugenic activity of Abeta. Furthermore, APP KO cells are resistant to the aneugenic activity of Abeta, as they have been shown previously to be resistant to Abeta-induced tau phosphorylation and cell toxicity. These results indicate that Abeta-induced microtubule dysfunction leads to aneuploid neurons and may thereby contribute to the pathogenesis of AD.

  13. Periventricular heterotopia and white matter abnormalities in a girl with mosaic ring chromosome 6.

    PubMed

    Nishigaki, Satsuki; Hamazaki, Takashi; Saito, Mika; Yamamoto, Toshiyuki; Seto, Toshiyuki; Shintaku, Haruo

    2015-01-01

    Ring chromosome 6 is a rare chromosome abnormality that arises typically de novo. The phenotypes can be highly variable, ranging from almost normal to severe malformations and neurological defects. We report a case of a 3-year-old girl with mosaic ring chromosome 6 who presented with being small for gestational age and intellectual disability, and whose brain MRI later revealed periventricular heterotopia and white matter abnormalities. Mosaicism was identified in peripheral blood cells examined by standard G-bands, mos 46,XX,r(6)(p25q27)[67]/45,XX,-6[25]/46,XX,dic r(6:6)(p25q27:p25q27)[6]/47,XX,r(6)(p25q27) × 2[2]. Using array-comparative genomic hybridization, we identified terminal deletion of 6q27 (1.5 Mb) and no deletion on 6p. To our knowledge, this is the first report of periventricular heterotopia and white matter abnormalities manifested in a patient with ring chromosome 6. These central nervous system malformations are further discussed in relation to molecular genetics.

  14. Clinical and molecular cytogenetic studies in ring chromosome 5: report of a child with congenital abnormalities.

    PubMed

    Basinko, Audrey; Giovannucci Uzielli, Maria Luisa; Scarselli, Gloria; Priolo, Manuela; Timpani, Giuseppina; De Braekeleer, Marc

    2012-02-01

    We report here a child with a ring chromosome 5 (r(5)) associated with facial dysmorphology and multiple congenital abnormalities. Fluorescent in situ hybridization (FISH) using bacterial artificial chromosome (BAC) clones was performed to determine the breakpoints involved in the r(5). The 5p deletion extended from 5p13.2-3 to 5pter and measured 34.61 Mb (range: 33.7-35.52 Mb) while the 5q deletion extended from 5q35.3 to 5qter and measured 2.44 Mb (range: 2.31-2.57 Mb). The patient presented signs such as microcephaly, hypertelorism, micrognathia and epicanthal folds, partially recalling those of a deletion of the short arm of chromosome 5 and the "cri-du-chat" syndrome. The most striking phenotypic features were the congenital heart abnormalities which have been frequently reported in deletions of the distal part of the long arm of chromosome 5 and in rings leading to a 5q35-5qter deletion. However, the NKX2-5 gene, which has been related to congenital heart defects, was not deleted in our patient, nor presumably to some other patients with 5q35.3-5qter deletion. We propose that VEGFR3, deleted in our patient, could be a candidate gene for the congenital heart abnormalities observed. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  15. Analysis and visualization of chromosomal abnormalities in SNP data with SNPscan

    PubMed Central

    Ting, Jason C; Ye, Ying; Thomas, George H; Ruczinski, Ingo; Pevsner, Jonathan

    2006-01-01

    Background A variety of diseases are caused by chromosomal abnormalities such as aneuploidies (having an abnormal number of chromosomes), microdeletions, microduplications, and uniparental disomy. High density single nucleotide polymorphism (SNP) microarrays provide information on chromosomal copy number changes, as well as genotype (heterozygosity and homozygosity). SNP array studies generate multiple types of data for each SNP site, some with more than 100,000 SNPs represented on each array. The identification of different classes of anomalies within SNP data has been challenging. Results We have developed SNPscan, a web-accessible tool to analyze and visualize high density SNP data. It enables researchers (1) to visually and quantitatively assess the quality of user-generated SNP data relative to a benchmark data set derived from a control population, (2) to display SNP intensity and allelic call data in order to detect chromosomal copy number anomalies (duplications and deletions), (3) to display uniparental isodisomy based on loss of heterozygosity (LOH) across genomic regions, (4) to compare paired samples (e.g. tumor and normal), and (5) to generate a file type for viewing SNP data in the University of California, Santa Cruz (UCSC) Human Genome Browser. SNPscan accepts data exported from Affymetrix Copy Number Analysis Tool as its input. We validated SNPscan using data generated from patients with known deletions, duplications, and uniparental disomy. We also inspected previously generated SNP data from 90 apparently normal individuals from the Centre d'Étude du Polymorphisme Humain (CEPH) collection, and identified three cases of uniparental isodisomy, four females having an apparently mosaic X chromosome, two mislabelled SNP data sets, and one microdeletion on chromosome 2 with mosaicism from an apparently normal female. These previously unrecognized abnormalities were all detected using SNPscan. The microdeletion was independently confirmed by

  16. Chromosome abnormalities additional to the Philadelphia chromosome at the diagnosis of chronic myelogenous leukemia: pathogenetic and prognostic implications.

    PubMed

    Zaccaria, Alfonso; Testoni, Nicoletta; Valenti, Anna Maria; Luatti, Simona; Tonelli, Michela; Marzocchi, Giulia; Cipriani, Raffaella; Baldazzi, Carmen; Giannini, Barbara; Stacchini, Monica; Gamberini, Carla; Castagnetti, Fausto; Rosti, Gianantonio; Azzena, Annalisa; Cavazzini, Francesco; Cianciulli, Anna Maria; Dalsass, Alessia; Donti, Emilio; Giugliano, Emilia; Gozzetti, Alessandro; Grimoldi, Maria Grazia; Ronconi, Sonia; Santoro, Alessandra; Spedicato, Francesco; Zanatta, Lucia; Baccarani, Michele

    2010-06-01

    Additional chromosome abnormalities (ACAs) occur in less than 10% of cases at diagnosis of Philadelphia chromosome (Ph)-positive chronic myelogenous leukemia (CML). In some cases, on the basis of the persistence of the ACAs in Ph-negative cells after response to imatinib, a secondary origin of the Ph chromosome has been demonstrated. In this study, the possible prognostic value of this phenomenon was evaluated. Thirty-six Ph-positive CML patients were included in the study. In six patients, ACAs persisted after the disappearance of the Ph. A complete cytogenetic response (CCR) was obtained in five of these six patients, and five of six also had a high Sokal score. In all the other cases, ACAs disappeared together (in cases of response to therapy with imatinib) or persisted with the Ph (in cases of no response to imatinib). In the former cases, the primary origin of the Ph was demonstrated. CCR was obtained in 22 cases (17 with low to intermediate Sokal scores), while no response was observed in 8 patients (5 with a high Sokal score). Sokal score seems to maintain its prognostic value for patients in whom the Ph occurs as a primary event, but not in those in whom it occurs as a secondary one. Copyright 2010 Elsevier Inc. All rights reserved.

  17. Chromosome Segregation: The Bigger They Come, the Harder They Fall.

    PubMed

    Baudoin, Nicolaas C; Cimini, Daniela

    2018-06-04

    Aneuploidy is frequently found to affect individual chromosomes differentially, but it is unclear whether this depends on inter-chromosome differences in missegregation rates. A new study presents evidence that, in the Indian muntjac, centromere-kinetochore size influences the rate at which chromosomes missegregate. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. The Argonaute CSR-1 and its 22G-RNA cofactors are required for holocentric chromosome segregation.

    PubMed

    Claycomb, Julie M; Batista, Pedro J; Pang, Ka Ming; Gu, Weifeng; Vasale, Jessica J; van Wolfswinkel, Josien C; Chaves, Daniel A; Shirayama, Masaki; Mitani, Shohei; Ketting, René F; Conte, Darryl; Mello, Craig C

    2009-10-02

    RNAi-related pathways regulate diverse processes, from developmental timing to transposon silencing. Here, we show that in C. elegans the Argonaute CSR-1, the RNA-dependent RNA polymerase EGO-1, the Dicer-related helicase DRH-3, and the Tudor-domain protein EKL-1 localize to chromosomes and are required for proper chromosome segregation. In the absence of these factors chromosomes fail to align at the metaphase plate and kinetochores do not orient to opposing spindle poles. Surprisingly, the CSR-1-interacting small RNAs (22G-RNAs) are antisense to thousands of germline-expressed protein-coding genes. Nematodes assemble holocentric chromosomes in which continuous kinetochores must span the expressed domains of the genome. We show that CSR-1 interacts with chromatin at target loci but does not downregulate target mRNA or protein levels. Instead, our findings support a model in which CSR-1 complexes target protein-coding domains to promote their proper organization within the holocentric chromosomes of C. elegans.

  19. Do the same traffic rules apply? Directional chromosome segregation by SpoIIIE and FtsK.

    PubMed

    Besprozvannaya, Marina; Burton, Briana M

    2014-08-01

    Over a decade of studies have tackled the question of how FtsK/SpoIIIE translocases establish and maintain directional DNA translocation during chromosome segregation in bacteria. FtsK/SpoIIIE translocases move DNA in a highly processive, directional manner, where directionality is facilitated by sequences on the substrate DNA molecules that are being transported. In recent years, structural, biochemical, single-molecule and high-resolution microscopic studies have provided new insight into the mechanistic details of directional DNA segregation. Out of this body of work, a series of models have emerged and, ultimately, yielded two seemingly opposing models: the loading model and the target search model. We review these recent mechanistic insights into directional DNA movement and discuss the data that may serve to unite these suggested models, as well as propose future directions that may ultimately solve the debate. © 2014 John Wiley & Sons Ltd.

  20. Overview of Epidemiology, Genetics, Birth Defects, and Chromosome Abnormalities Associated With CDH

    PubMed Central

    Pober, Barbara R.

    2010-01-01

    Congenital diaphragmatic hernia (CDH) is a common and well-studied birth defect. The etiology of most cases remains unknown but increasing evidence points to genetic causation. The data supporting genetic etiologies which are detailed below include the association of CDH with recurring chromosome abnormalities, the existence of CDH-multiplex families, and the co-occurrence of CDH with additional congenital malformations. PMID:17436298

  1. Cryptic deletions and inversions of chromosome 21 in a phenotypically normal infant with transient abnormal myelopoiesis: a molecular cytogenetic study.

    PubMed

    Kempski, H M; Craze, J L; Chessells, J M; Reeves, B R

    1998-11-01

    A case of transient abnormal myelopoiesis in a normal newborn without features of Down syndrome is described. The majority of bone marrow cells analysed belonged to a chromosomally abnormal clone with trisomy for chromosomes 18 and 21. Complex intrachromosomal rearrangements of one chromosome 21, demonstrated by fluorescence in situ hybridization using locus-specific probes, were found in a minor population of the clonal cells. These rearrangements involved loci previously shown to be rearranged in the leukaemic cells from patients with Down syndrome and leukaemia. However, the child's myeloproliferation resolved rapidly, with disappearance of the abnormal clone, and 3.5 years later she remains well.

  2. Polymer modeling of the E. coli genome reveals the involvement of locus positioning and macrodomain structuring for the control of chromosome conformation and segregation

    PubMed Central

    Junier, Ivan; Boccard, Frédéric; Espéli, Olivier

    2014-01-01

    The mechanisms that control chromosome conformation and segregation in bacteria have not yet been elucidated. In Escherichia coli, the mere presence of an active process remains an open question. Here, we investigate the conformation and segregation pattern of the E. coli genome by performing numerical simulations on a polymer model of the chromosome. We analyze the roles of the intrinsic structuring of chromosomes and the forced localization of specific loci, which are observed in vivo. Specifically, we examine the segregation pattern of a chromosome that is divided into four structured macrodomains (MDs) and two non-structured regions. We find that strong osmotic-like organizational forces, which stem from the differential condensation levels of the chromosome regions, dictate the cellular disposition of the chromosome. Strikingly, the comparison of our in silico results with fluorescent imaging of the chromosome choreography in vivo reveals that in the presence of MDs the targeting of the origin and terminus regions to specific positions are sufficient to generate a segregation pattern that is indistinguishable from experimentally observed patterns. PMID:24194594

  3. Clinical accuracy of abnormal cell-free fetal DNA results for the sex chromosomes.

    PubMed

    Scibetta, Emily W; Gaw, Stephanie L; Rao, Rashmi R; Silverman, Neil S; Han, Christina S; Platt, Lawrence D

    2017-12-01

    To investigate factors associated with abnormal cell-free DNA (cfDNA) results for sex chromosomes (SCs). This is a retrospective cohort study of abnormal cfDNA results for SC at a referral practice from March 2013 to July 2015. Cell-free DNA results were abnormal if they were positive for SC aneuploidy (SCA), inconclusive, or discordant with ultrasound (US) findings. Primary outcome was concordance with karyotype or postnatal evaluation. Of 50 abnormal cfDNA results for SC, 31 patients (62%) were positive for SCA, 13 (26%) were inconclusive, and 6 (12%) were sex discordant on US. Of SCA results, 19 (61%) were reported as 45,X and 12 (39%) were SC trisomy. Abnormal karyotypes were confirmed in 8/23 (35%) of SC aneuploidy and 1/5 (20%) of inconclusive results. Abnormal SC cfDNA results were associated with in vitro fertilization (P = .001) and twins (P < .001). Sex discordance between cfDNA and US was associated with twin gestation (P < .001). In our cohort, abnormal SC cfDNA results were associated with in vitro fertilization and twins. Our results indicate cfDNA for sex prediction in twins of limited utility. Positive predictive value and sensitivity for SC determination were lower than previously reported. © 2017 John Wiley & Sons, Ltd.

  4. Prenatal diagnosis of sex chromosome abnormalities: the 8-year experience of a single medical center.

    PubMed

    Vaknin, Zvi; Reish, Orit; Ben-Ami, Ido; Heyman, Eli; Herman, Arie; Maymon, Ron

    2008-01-01

    To assess the indications for prenatal karyotyping of sex chromosomal abnormalities (SCAs) during pregnancy. All singleton pregnancies interrupted in our institute because of SCAs (1998-2005) were categorized into subgroups of 45,XO (Turner syndrome), 47,XXY (Klinefelter syndrome), 47,XXX and 47,XYY. The indications for prenatal diagnostic testing were recorded. There were 67 SCAs pregnancies: 33% Turner syndrome, 28% Klinefelter syndrome, 21% 47,XXX and 18% 47,XYY. Maternal age was similar among the 4 groups (34 +/- 5, range 25-42 years). The main indications for fetal karyotyping were abnormal Down's syndrome (DS) screening or ultrasound findings, advanced maternal age (> or =35 years), and parental request. About 2/3 of the Turner and 47,XYY cases had either abnormal DS screening tests or sonographic findings, such as: increased nuchal translucency, mainly cystic hygroma and fetal hydrops. However, fetal karyotyping in more than 2/3 of the 47,XXX and 47,XXY cases was mainly performed because of advanced maternal age, and the diagnosis of fetal SCAs was coincidental (p <0.03). Our recent suggestion to expand the DS screening capacity to other chromosomal abnormalities including SCAs is further supported. Prenatal detection seems to be promising for Turner syndrome and possibly for 47,XYY syndrome, while other SCAs are less likely to be detected either by ultrasound or biochemical screening. (c) 2007 S. Karger AG, Basel

  5. Current controversies in prenatal diagnosis 2: Cell-free DNA prenatal screening should be used to identify all chromosome abnormalities.

    PubMed

    Chitty, Lyn S; Hudgins, Louanne; Norton, Mary E

    2018-02-01

    Noninvasive prenatal testing (NIPT) using cell-free DNA (cfDNA) from maternal serum has been clinically available since 2011. This technology has revolutionized our ability to screen for the common aneuploidies trisomy 21 (Down syndrome), trisomy 18, and trisomy 13. More recently, clinical laboratories have offered screening for other chromosome abnormalities including sex chromosome abnormalities and copy number variants (CNV) without little published data on the sensitivity, specificity, and positive predictive value. In this debate, the pros and cons of performing prenatal screening via cfDNA for all chromosome abnormalities is discussed. At the time of the debate in 2017, the general consensus was that the literature does not yet support using this technology to screen for all chromosome abnormalities and that education is key for both providers and the patients so that the decision-making process is as informed as possible. © 2018 John Wiley & Sons, Ltd.

  6. Novel rapid molecular diagnosis of fetal chromosomal abnormalities associated with recurrent pregnancy loss.

    PubMed

    Yang, Lan; Tang, Ye; Lu, Mudan; Yang, Yuefen; Xiao, Jianping; Wang, Qiaoxia; Yang, Canfeng; Tao, Hehua; Xiang, Jingying

    2016-12-01

    Labor-intensive karyotyping is used as the reference standard diagnostic test to identify copy number variants (CNVs) in the fetal genome after recurrent pregnancy loss. Our aim was to present and evaluate a novel molecular assay called CNVplex that could potentially be used as an alternative method to conventional karyotyping for diagnosing fetal chromosomal abnormalities associated with recurrent pregnancy loss. Using karyotyping as the reference standard, CNVplex was performed to identify fetal chromosomal abnormalities in the chorionic villus samples from 76 women experiencing at least two pregnancy losses. Its diagnostic accuracy, sensitivity, and specificity were evaluated to detect aneuploidies associated with recurrent pregnancy loss. Turnaround time and costs of CNVplex were also measured. Diagnostic accuracy of CNVplex in aneuploidies that are associated with recurrent pregnancy loss was 1.0 (95% CI 0.94-1.0), sensitivity was 100% (95% CI 0.89-1.0), and specificity was 100% (95% CI 0.875-1.0). Diagnostic accuracy of CNVplex was similar to that of karyotyping. Both karyotyping and CNVplex assay detected 27 autosomal trisomies, three 45,X monosomies, and three polyploidies. CNVplex also detected additional novel structural abnormalities of the fetal genome. Compared with karyotyping, CNVplex significantly (p = 0.001) reduced the waiting time by 13.98 days (95% CI 13.88-14.08) and the cost by US $241 (95% CI 234.53-247.47). CNVplex is a novel effective assay for diagnosing fetal chromosomal abnormalities associated with recurrent pregnancy loss. In the routine clinical work-up of recurrent pregnancy loss, diagnostic accuracy of CNVplex is comparable to that of conventional karyotyping but it requires less waiting time and has lower cost. © 2016 Nordic Federation of Societies of Obstetrics and Gynecology.

  7. Sex chromosomal abnormalities associated with equine infertility: validation of a simple molecular screening tool in the Purebred Spanish Horse.

    PubMed

    Anaya, G; Molina, A; Valera, M; Moreno-Millán, M; Azor, P; Peral-García, P; Demyda-Peyrás, S

    2017-08-01

    Chromosomal abnormalities in the sex chromosome pair (ECAX and ECAY) are widely associated with reproductive problems in horses. However, a large proportion of these abnormalities remains undiagnosed due to the lack of an affordable diagnostic tool that allows for avoiding karyotyping tests. Hereby, we developed an STR (single-tandem-repeat)-based molecular method to determine the presence of the main sex chromosomal abnormalities in horses in a fast, cheap and reliable way. The frequency of five ECAX-linked (LEX026, LEX003, TKY38, TKY270 and UCDEQ502) and two ECAY-linked (EcaYH12 and SRY) markers was characterized in 261 Purebred Spanish Horses to determine the efficiency of the methodology developed to be used as a chromosomal diagnostic tool. All the microsatellites analyzed were highly polymorphic, with a sizeable number of alleles (polymorphic information content > 0.5). Based on this variability, the methodology showed 100% sensitivity and 99.82% specificity to detect the most important sex chromosomal abnormalities reported in horses (chimerism, Turner's syndrome and sex reversal syndromes). The method was also validated with 100% efficiency in 10 individuals previously diagnosed as chromosomally aberrant. This STR screening panel is an efficient and reliable molecular-cytogenetic tool for the early detection of sex chromosomal abnormalities in equines that could be included in breeding programs to save money, effort and time of veterinary practitioners and breeders. © 2017 Stichting International Foundation for Animal Genetics.

  8. Rare X Chromosome Abnormalities in Systemic Lupus Erythematosus and Sjögren's Syndrome.

    PubMed

    Sharma, Rohan; Harris, Valerie M; Cavett, Joshua; Kurien, Biji T; Liu, Ke; Koelsch, Kristi A; Fayaaz, Anum; Chaudhari, Kaustubh S; Radfar, Lida; Lewis, David; Stone, Donald U; Kaufman, C Erick; Li, Shibo; Segal, Barbara; Wallace, Daniel J; Weisman, Michael H; Venuturupalli, Swamy; Kelly, Jennifer A; Pons-Estel, Bernardo; Jonsson, Roland; Lu, Xianglan; Gottenberg, Jacques-Eric; Anaya, Juan-Manuel; Cunninghame-Graham, Deborah S; Huang, Andrew J W; Brennan, Michael T; Hughes, Pamela; Alevizos, Ilias; Miceli-Richard, Corinne; Keystone, Edward C; Bykerk, Vivian P; Hirschfield, Gideon; Nordmark, Gunnel; Bucher, Sara Magnusson; Eriksson, Per; Omdal, Roald; Rhodus, Nelson L; Rischmueller, Maureen; Rohrer, Michael; Wahren-Herlenius, Marie; Witte, Torsten; Alarcón-Riquelme, Marta; Mariette, Xavier; Lessard, Christopher J; Harley, John B; Ng, Wan-Fai; Rasmussen, Astrid; Sivils, Kathy L; Scofield, R Hal

    2017-11-01

    Sjögren's syndrome (SS) and systemic lupus erythematosus (SLE) are related by clinical and serologic manifestations as well as genetic risks. Both diseases are more commonly found in women than in men, at a ratio of ~10 to 1. Common X chromosome aneuploidies, 47,XXY and 47,XXX, are enriched among men and women, respectively, in either disease, suggesting a dose effect on the X chromosome. We examined cohorts of SS and SLE patients by constructing intensity plots of X chromosome single-nucleotide polymorphism alleles, along with determining the karyotype of selected patients. Among ~2,500 women with SLE, we found 3 patients with a triple mosaic, consisting of 45,X/46,XX/47,XXX. Among ~2,100 women with SS, 1 patient had 45,X/46,XX/47,XXX, with a triplication of the distal p arm of the X chromosome in the 47,XXX cells. Neither the triple mosaic nor the partial triplication was found among the controls. In another SS cohort, we found a mother/daughter pair with partial triplication of this same region of the X chromosome. The triple mosaic occurs in ~1 in 25,000-50,000 live female births, while partial triplications are even rarer. Very rare X chromosome abnormalities are present among patients with either SS or SLE and may inform the location of a gene(s) that mediates an X dose effect, as well as critical cell types in which such an effect is operative. © 2017, American College of Rheumatology.

  9. Prader-Willi-like phenotypes: a systematic review of their chromosomal abnormalities.

    PubMed

    Rocha, C F; Paiva, C L A

    2014-03-31

    Prader-Willi syndrome (PWS) is caused by the lack of expression of genes located on paternal chromosome 15q11-q13. This lack of gene expression may be due to a deletion in this chromosomal segment, to maternal uniparental disomy of chromosome 15, or to a defect in the imprinting center on 15q11-q13. PWS is characterized by hypotonia during the neonatal stage and in childhood, accompanied by a delay in neuropsychomotor development. Overeating, obesity, and mental deficiency arise later on. The syndrome has a clinical overlap with other diseases, which makes it difficult to accurately diagnose. The purpose of this article is to review the Prader-Willi-like phenotype in the scientific literature from 2000 to 2013, i.e., to review the cases of PWS caused by chromosomal abnormalities different from those found on chromosome 15. A search was carried out using the "National Center for Biotechnology Information" (www.pubmed.com) and "Scientific Electronic Library Online (www.scielo.br) databases and combinations of key words such as "Prader-Willi-like phenotype" and "Prader-Willi syndrome phenotype". Editorials, letters, reviews, and guidelines were excluded. Articles chosen contained descriptions of patients diagnosed with the PWS phenotype but who were negative for alterations on 15q11-q13. Our search found 643 articles about PWS, but only 14 of these matched with the Prader-Willi-like phenotype and with the selected years of publication (2000-2013). If two or more articles reported the same chromosomal alterations for Prader-Willi-like phenotype, the most recent was chosen. Twelve articles of 14 were case reports and 2 reported series of cases.

  10. Complex chromosomal abnormalities in a patient with HTLV-1 positive T-cell leukemia

    SciTech Connect

    Hyde, P.; Macera, M.J.; Gogineni, S.K.

    HTLV-1 positive adult T-cell leukemia (ATL) is associated with numerous chromosomal abnormalities. The chromosomal rearrangements can be extremely complex and additional material is often present, making precise identification by routine cytogenetic techniques difficult. We report a case of ATL that was established of bone marrow cells by both QFQ and GTG banding techniques revealed a highly complex 49,XX,der(2)t(2;?)(q37;?),+5,+2mar karyotype in the dividing cells. The identical cytogenetic findings were also seen in unstimulated peripheral blood collected one week later. Using the FISH-technique, we applied spectrum green-labeled No. 1- and No. 7-specific WCP, spectrum orange-labeled No. 2- and No. 5-specific WCP (GIBCO/BRL,more » Gaithersburg, MD) and biotin-labeled No. 18-specific WCP (Oncor, Gaithersburg, MD) to metaphase chromosomes. The large marker chromosome was identified as an extra 1q arm, the material attached to the distal 2q was additional 7q. The presence of three No. 5 chromosomes was verified and the small marker was determined to be an extra partial 5p in Robertsonian translocation with an additional partial 18q arm. The karyotype was revised to 49,XX,+1q,der(2)t(2;7)(q37;q22),+5,+t(5;18)(p14{r_arrow}p11::q11{r_arrow}q12). Identification of the numerous chromosomal anomalies associated with the disease by molecular techniques shall lead to a better understanding of this deadly cancer.« less

  11. Chromosome rearrangements, recombination suppression, and limited segregation distortion in hybrids between Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri) and rainbow trout (O. mykiss)

    USGS Publications Warehouse

    Ostberg, Carl O.; Hauser, Lorenz; Pritchard, Victoria L.; Garza, John C.; Naish, Kerry A.

    2013-01-01

    Chromosome rearrangements suppressed recombination in the hybrids. This result supports several previous findings demonstrating that recombination suppression restricts gene flow between chromosomes that differ by arrangement. Conservation of synteny and map order between the hybrid and rainbow trout maps and minimal segregation distortion in the hybrids suggest rainbow and Yellowstone cutthroat trout genomes freely introgress across chromosomes with similar arrangement. Taken together, these results suggest that rearrangements impede introgression. Recombination suppression across rearrangements could enable large portions of non-recombined chromosomes to persist within admixed populations.

  12. Genetic counseling for men with recurrent pregnancy loss or recurrent implantation failure due to abnormal sperm chromosomal aneuploidy.

    PubMed

    Kohn, Taylor P; Kohn, Jaden R; Darilek, Sandra; Ramasamy, Ranjith; Lipshultz, Larry

    2016-05-01

    The purpose of this study is to review recurrent pregnancy loss (RPL) due to sperm chromosomal abnormalities and discuss the genetic counseling that is required for men with sperm chromosomal abnormalities. The literature was reviewed, and a genetic counselor lends her expertise as to how couples with RPL and sperm chromosomal abnormalities ought to be counseled. The review of the literature was performed using MEDLINE. Sperm fluorescence in situ hybridization (FISH) can be used to determine if disomy or unbalanced chromosomal translocations are present. In men with aneuploidy in sperm or who carry a chromosomal translocation, pre-implantation genetic screening (PGS) combined with in vitro fertilization (IVF) and intra-cytoplasmic sperm injection (ICSI) can increase chances of live birth. In men with abnormal sperm FISH results, the degree of increased risk of abnormal pregnancy remains unclear. Genetic counselors can provide information to couples about the risk for potential trisomies and sex chromosome aneuploidies and discuss their reproductive and testing options such as PGS, use of donor sperm, and adoption. The provision of genetic counseling also allows a couple to be educated about recommended prenatal testing since pregnancies conceived with a partner who has had abnormal sperm FISH are considered to be at increased risk for aneuploidy. We review the literature and discuss genetic counseling for couples with RPL or recurrent implantation failure due to increased sperm aneuploidy.

  13. Outcome of chromosomally abnormal pregnancies in Lebanon: obstetricians' roles during and after prenatal diagnosis.

    PubMed

    Eldahdah, Lama T; Ormond, Kelly E; Nassar, Anwar H; Khalil, Tayma; Zahed, Laila F

    2007-06-01

    To better understand obstetrician experiences in Lebanon when disclosing abnormal amniocentesis results. Structured interviews with 38 obstetricians identified as caregivers from the American University of Beirut Medical Center Cytogenetics Laboratory database of patients with abnormal amniocentesis results between 1999 and 2005. Obstetricians were primarily male, Christian, and with an average of 14 years of experience. They reported doing most pre-amniocentesis counseling, including discussion of risk for common autosomal aneuplodies (95%), and procedure-related risk (95%). Obstetricians reported that 80% of patients at risk for aneuploidy underwent amniocentesis. The study population reported on 143 abnormal test results (124 autosomal abnormalities). When disclosing results, obstetricians reportedly discussed primarily physical and cognitive features of the diagnosis. They varied in levels of directiveness and comfort in providing information. Our records showed that 59% of pregnancies with sex chromosome abnormalities were terminated compared to 90% of those with autosomal aneuploidies; various reasons were proposed by obstetricians. This study is among the few to assess prenatal diagnosis practices in the Middle East, with a focus on the role of the obstetrician. Given the influence of culture and social norms on prenatal decision-making, it remains important to understand the various impacts on clinical practice in many nations. (c) 2007 John Wiley & Sons, Ltd.

  14. Human female meiosis revised: new insights into the mechanisms of chromosome segregation and aneuploidies from advanced genomics and time-lapse imaging.

    PubMed

    Capalbo, Antonio; Hoffmann, Eva R; Cimadomo, Danilo; Ubaldi, Filippo Maria; Rienzi, Laura

    2017-11-01

    The unbalanced transmission of chromosomes in human gametes and early preimplantation embryos causes aneuploidy, which is a major cause of infertility and pregnancy failure. A baseline of 20% of human oocytes are estimated to be aneuploid and this increases exponentially from 30 to 35 years, reaching on average 80% by 42 years. As a result, reproductive senescence in human females is predominantly determined by the accelerated decline in genetic quality of oocytes from 30 years of age. Understanding mechanisms of chromosome segregation and aneuploidies in the female germline is a crucial step towards the development of new diagnostic approaches and, possibly, for the development of therapeutic targets and molecules. Here, we have reviewed emerging mechanisms that may drive human aneuploidy, in particular the maternal age effect. We conducted a systematic search in PubMed Central of the primary literature from 1990 through 2016 following the PRISMA guidelines, using MeSH terms related to human aneuploidy. For model organism research, we conducted a literature review based on references in human oocytes manuscripts and general reviews related to chromosome segregation in meiosis and mitosis. Advances in genomic and imaging technologies are allowing unprecedented insight into chromosome segregation in human oocytes. This includes the identification of a novel chromosome segregation error, termed reverse segregation, as well as sister kinetochore configurations that were not predicted based on murine models. Elucidation of mechanisms that result in errors in chromosome segregation in meiosis may lead to therapeutic developments that could improve reproductive outcomes by reducing aneuploidy. © The Author 2017. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  15. Chromosomal abnormalities in azoospermic and non-azoospermic infertile men: numbers needed to be screened to prevent adverse pregnancy outcomes.

    PubMed

    Dul, E C; van Echten-Arends, J; Groen, H; Dijkhuizen, T; Land, J A; van Ravenswaaij-Arts, C M A

    2012-09-01

    How many infertile men who wish to conceive need to be screened for chromosomal abnormalities to prevent one miscarriage or the birth of one child with congenital anomalies (CAs)? In azoospermic men, the prevalence of chromosomal abnormalities is 15.2% and the number needed to be screened (NNS; minimum-maximum estimate) for a miscarriage is 80-88 and for a child with CAs is 790-3951. The prevalence of chromosomal abnormalities in non-azoospermic men is 2.3% and the NNS are 315-347 and 2543-12 723, respectively. Guidelines advise the screening of infertile men for chromosomal abnormalities to prevent miscarriages and children with congenital abnormalities, but no studies have been published on the effectiveness of this screening strategy. Retrospective cohort study of 1223 infertile men between 1994 and 2007. Men with azoospermia and men eligible for ICSI treatment visiting a university hospital fertility clinic in The Netherlands who underwent chromosomal analysis between 1994 and 2007 were identified retrospectively in a registry. Only cases of which at least one sperm analysis was available were included. Data were collected by chart review, with a follow-up of pregnancies and their outcomes until 2010. The chromosomal abnormalities were categorized according to their risk of unbalanced offspring, i.e. miscarriage and/or child with CAs. Multi-level analysis was used to estimate the impact of chromosomal abnormalities on the outcome of pregnancies in the different subgroups of our cohort. NNS for miscarriages and children with CAs were calculated based on data from our cohort and data published in the literature. A chromosomal abnormality was found in 12 of 79 men with azoospermia (15.2%) and in 26 of 1144 non-azoospermic men (2.3%). The chromosomal abnormalities were categorized based on the literature, into abnormalities with and abnormalities without increased risk for miscarriage and/or child with CAs. In our study group, there was no statistically significant

  16. Clinical application of chromosomal microarray analysis for the prenatal diagnosis of chromosomal abnormalities and copy number variations in fetuses with congenital heart disease.

    PubMed

    Xia, Yu; Yang, Yongchao; Huang, Shufang; Wu, Yueheng; Li, Ping; Zhuang, Jian

    2018-03-24

    This study aimed to determine chromosomal abnormalities and copy number variations (CNVs) in fetuses with congenital heart disease (CHD) by chromosomal microarray analysis (CMA). One hundred and ten cases with CHD detected by prenatal echocardiography were enrolled in the study; 27 cases were simple CHDs, and 83 were complex CHDs. Chromosomal microarray analysis was performed on the Affymetrix CytoScan HD platform. All annotated CNVs were validated by quantitative PCR. Chromosomal microarray analysis identified 6 cases with chromosomal abnormalities, including 2 cases with trisomy 21, 2 cases with trisomy 18, 1 case with trisomy 13, and 1 unusual case of mosaic trisomy 21. Pathogenic CNVs were detected in 15.5% (17/110) of the fetuses with CHDs, including 13 cases with CHD-associated CNVs. We further identified 10 genes as likely novel CHD candidate genes through gene functional enrichment analysis. We also found that pathogenic CMA results impacted the rate of pregnancy termination. This study shows that CMA is particularly effective for identifying chromosomal abnormalities and CNVs in fetuses with CHDs as well as having an effect on obstetrical outcomes. The elucidation of the genetic basis of CHDs will continue to expand our understanding of the etiology of CHDs. © 2018 John Wiley & Sons, Ltd.

  17. Condensin suppresses recombination and regulates double-strand break processing at the repetitive ribosomal DNA array to ensure proper chromosome segregation during meiosis in budding yeast

    PubMed Central

    Li, Ping; Jin, Hui; Yu, Hong-Guo

    2014-01-01

    During meiosis, homologues are linked by crossover, which is required for bipolar chromosome orientation before chromosome segregation at anaphase I. The repetitive ribosomal DNA (rDNA) array, however, undergoes little or no meiotic recombination. Hyperrecombination can cause chromosome missegregation and rDNA copy number instability. We report here that condensin, a conserved protein complex required for chromosome organization, regulates double-strand break (DSB) formation and repair at the rDNA gene cluster during meiosis in budding yeast. Condensin is highly enriched at the rDNA region during prophase I, released at the prophase I/metaphase I transition, and reassociates with rDNA before anaphase I onset. We show that condensin plays a dual role in maintaining rDNA stability: it suppresses the formation of Spo11-mediated rDNA breaks, and it promotes DSB processing to ensure proper chromosome segregation. Condensin is unnecessary for the export of rDNA breaks outside the nucleolus but required for timely repair of meiotic DSBs. Our work reveals that condensin coordinates meiotic recombination with chromosome segregation at the repetitive rDNA sequence, thereby maintaining genome integrity. PMID:25103240

  18. Condensin suppresses recombination and regulates double-strand break processing at the repetitive ribosomal DNA array to ensure proper chromosome segregation during meiosis in budding yeast.

    PubMed

    Li, Ping; Jin, Hui; Yu, Hong-Guo

    2014-10-01

    During meiosis, homologues are linked by crossover, which is required for bipolar chromosome orientation before chromosome segregation at anaphase I. The repetitive ribosomal DNA (rDNA) array, however, undergoes little or no meiotic recombination. Hyperrecombination can cause chromosome missegregation and rDNA copy number instability. We report here that condensin, a conserved protein complex required for chromosome organization, regulates double-strand break (DSB) formation and repair at the rDNA gene cluster during meiosis in budding yeast. Condensin is highly enriched at the rDNA region during prophase I, released at the prophase I/metaphase I transition, and reassociates with rDNA before anaphase I onset. We show that condensin plays a dual role in maintaining rDNA stability: it suppresses the formation of Spo11-mediated rDNA breaks, and it promotes DSB processing to ensure proper chromosome segregation. Condensin is unnecessary for the export of rDNA breaks outside the nucleolus but required for timely repair of meiotic DSBs. Our work reveals that condensin coordinates meiotic recombination with chromosome segregation at the repetitive rDNA sequence, thereby maintaining genome integrity. © 2014 Li et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  19. Implication of sperm chromosomal abnormalities in recurrent abortion and multiple implantation failure.

    PubMed

    Caseiro, Ana Lara; Regalo, Ana; Pereira, Elisa; Esteves, Telma; Fernandes, Fernando; Carvalho, Joaquim

    2015-10-01

    Currently, some infertility treatment centres provide sperm karyotype analysis, although the impact of sperm chromosomal abnormalities on fertility is not yet fully understood. Several studies using fluorescence in-situ hybridization (FISH) to analyse sperm chromosomal constitution discovered that the incidence of aneuploidy is increased in individuals with a history of repeated abortion or implantation failure and is even higher in cases of oligoasthenoteratozoospermia (OAT), abnormal somatic karyotype or in spermatozoa retrieved directly from the testis or epididymis, showing that the application of FISH in these cases may be of some benefit for improving the reproductive outcome. This article presents the results of clinical trials of FISH analysis on spermatozoa, the medical indications for performing this examination, its results in infertile patients and the advantages when performing genetic counselling prior to treatment. Also discussed is the possibility of applying the latest techniques of genetic analysis in these cases and the potential benefits for improving the prognosis of male infertility. Copyright © 2015 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

  20. Chromosomal abnormalities and copy number variations in fetal left-sided congenital heart defects.

    PubMed

    Jansen, Fenna A R; Hoffer, Mariette J V; van Velzen, Christine L; Plati, Stephani Klingeman; Rijlaarsdam, Marry E B; Clur, Sally-Ann B; Blom, Nico A; Pajkrt, Eva; Bhola, Shama L; Knegt, Alida C; de Boer, Marion A; Haak, Monique C

    2016-02-01

    To demonstrate the spectrum of copy number variants (CNVs) in fetuses with isolated left-sided congenital heart defects (CHDs), and analyse genetic content. Between 2003 and 2012, 200 fetuses were identified with left-sided CHD. Exclusion criteria were chromosomal rearrangements, 22q11.2 microdeletion and/or extra-cardiac malformations (n = 64). We included cases with additional minor anomalies (n = 39), such as single umbilical artery. In 54 of 136 eligible cases, stored material was available for array analysis. CNVs were categorized as either (likely) benign, (likely) pathogenic or of unknown significance. In 18 of the 54 isolated left-sided CHDs we found 28 rare CNVs (prevalence 33%, average 1.6 CNV per person, size 10.6 kb-2.2 Mb). Our interpretation yielded clinically significant CNVs in two of 54 cases (4%) and variants of unknown significance in three other cases (6%). In left-sided CHDs that appear isolated, with normal chromosome analysis and 22q11.2 FISH analysis, array analysis detects clinically significant CNVs. When counselling parents of a fetus with a left-sided CHD it must be taken into consideration that aside from the cardiac characteristics, the presence of extra-cardiac malformations and chromosomal abnormalities influence the treatment plan and prognosis. © 2015 John Wiley & Sons, Ltd.

  1. Functional Characterization of CENP-A Post-Translational Modifications in Chromosome Segregation

    DTIC Science & Technology

    2016-09-01

    our overall findings in discussion part, and finally we will explain major materials and methods we used. Results CENP-A α-amino methylation...centromere and kinetochore and accurate segregation of the genetic materials . Moreover, we established that centromere/kinetochore defects in the absence...developed. Materials and methods: Creation of CENP-A complete replacement RPE cells: RPE CENP-A knockout cell line generated by Don Cleaveland Lab7 used

  2. [Prevalence of congenital abnormalities identified in fetuses with 13, 18 and 21 chromosomal trisomy].

    PubMed

    Emer, Caroline Soares Cristofari; Duque, Julio Alejandro Peña; Müller, Ana Lúcia Letti; Gus, Rejane; Sanseverino, Maria Teresa Vieira; da Silva, André Anjos; Magalhães, José Antonio de Azevedo

    2015-07-01

    To describe the prevalence of malformations found in fetuses with trisomy of chromosomes 13, 18 and 21 by identifying the most frequent within each condition. A retrospective cross-sectional study with the analysis of trisomy cases of chromosomes 13, 18 and 21 diagnosed through fetal karyotype obtained by amniocentesis/cordocentesis, between October 1994 and May 2014, at a Teaching Hospital in Brazil Southern Region. Malformations identified through morphological ultrasonography were described and, subsequently, confirmed in newborn examinations and/or fetal autopsy. The results were analyzed using Fisher's test and analysis of variance (ANOVA), with a 5% level of significance (p=0.05). Sixty-nine cases of trisomy were diagnosed among 840 exams; nine were excluded due to outcome outside Hospital de Clínicas de Porto Alegre or incomplete records, remaining 60 cases (nine cases of chromosome 13 trisomy, 26 of chromosome 18, and 25 of chromosome 21). In all three groups, heart disease occurred in most cases; the ventricular septal defect was more prevalent and occurred in 66.7% of the trisomy 13 group. Gastrointestinal abnormalities were more prevalent in the trisomy 18 group, especially omphalocele (38.5%; p<0.01). Genitourinary anomalies were more significantly frequent in the trisomy 13 group (pyelectasis, 55.6% - p<0.01; ambiguous genitalia, 33.3% - p=0.01). Central nervous system defects were identified in all cases of trisomy 13. Facial cracks were significantly more prevalent among fetuses with trisomy 13 (66.7%; p<0.01). Hand and feet malformations significantly differed among the trisomy groups. Hand defects occurred in 50% of trisomy 18 cases, and in 44.4% of all trisomy 13 cases (p<0.01); congenital clubfoot was more common in the trisomy 18 group, being detected in 46.2% of fetuses (p<0.01). The abnormalities were found in 50.9, 27.3 and 21.7% of trisomy 18, 13 and 21 cases respectively. Many fetal malformations identified at ultrasound are suggestive of

  3. Array-Based Comparative Genomic Hybridization for the Genomewide Detection of Submicroscopic Chromosomal Abnormalities

    PubMed Central

    Vissers, Lisenka E. L. M. ; de Vries, Bert B. A. ; Osoegawa, Kazutoyo ; Janssen, Irene M. ; Feuth, Ton ; Choy, Chik On ; Straatman, Huub ; van der Vliet, Walter ; Huys, Erik H. L. P. G. ; van Rijk, Anke ; Smeets, Dominique ; van Ravenswaaij-Arts, Conny M. A. ; Knoers, Nine V. ; van der Burgt, Ineke ; de Jong, Pieter J. ; Brunner, Han G. ; van Kessel, Ad Geurts ; Schoenmakers, Eric F. P. M. ; Veltman, Joris A. 

    2003-01-01

    Microdeletions and microduplications, not visible by routine chromosome analysis, are a major cause of human malformation and mental retardation. Novel high-resolution, whole-genome technologies can improve the diagnostic detection rate of these small chromosomal abnormalities. Array-based comparative genomic hybridization allows such a high-resolution screening by hybridizing differentially labeled test and reference DNAs to arrays consisting of thousands of genomic clones. In this study, we tested the diagnostic capacity of this technology using ∼3,500 flourescent in situ hybridization–verified clones selected to cover the genome with an average of 1 clone per megabase (Mb). The sensitivity and specificity of the technology were tested in normal-versus-normal control experiments and through the screening of patients with known microdeletion syndromes. Subsequently, a series of 20 cytogenetically normal patients with mental retardation and dysmorphisms suggestive of a chromosomal abnormality were analyzed. In this series, three microdeletions and two microduplications were identified and validated. Two of these genomic changes were identified also in one of the parents, indicating that these are large-scale genomic polymorphisms. Deletions and duplications as small as 1 Mb could be reliably detected by our approach. The percentage of false-positive results was reduced to a minimum by use of a dye-swap-replicate analysis, all but eliminating the need for laborious validation experiments and facilitating implementation in a routine diagnostic setting. This high-resolution assay will facilitate the identification of novel genes involved in human mental retardation and/or malformation syndromes and will provide insight into the flexibility and plasticity of the human genome. PMID:14628292

  4. Plk1 is essential for proper chromosome segregation during meiosis I/meiosis II transition in pig oocytes.

    PubMed

    Zhang, Zixiao; Chen, Changchao; Ma, Liying; Yu, Qiuchen; Li, Shuai; Abbasi, Benazir; Yang, Jiayi; Rui, Rong; Ju, Shiqiang

    2017-08-29

    Polo-like kinase 1 (Plk1), as a characteristic regulator in meiosis, organizes multiple biological events of cell division. Although Plk1 has been implicated in various functions in somatic cell mitotic processes, considerably less is known regarding its function during the transition from metaphase I (MI) to metaphase II (MII) stage in oocyte meiotic progression. In this study, the possible role of Plk1 during the MI-to-MII stage transition in pig oocytes was addressed. Initially, the spatiotemporal expression and subcellular localization pattern of Plk1 were revealed in pig oocytes from MI to MII stage using indirect immunofluorescence and confocal microscopy imaging techniques combined with western blot analyses. Moreover, a highly selective Plk1 inhibitor, GSK461364, was used to determine the potential role of Plk1 during this MI-to-MII transition progression. Upon expression, Plk1 exhibited a specific dynamic intracellular localization, and co-localization of Plk1 with α-tubulin was revealed in the meiotic spindle of pig oocyte during the transition from MI to MII stage. GSK461364 treatment significantly blocked the first polar body (pbI) emission in a dose-dependent manner and resulted in a failure of meiotic maturation, with a larger percentage of the GSK461364-treated oocytes arresting in the anaphase-telophase I (ATI) stage. Further subcellular structure examination results showed that inhibition of Plk1 with GSK461364 had no visible effect on spindle assembly but caused a significantly higher proportion of the treated oocytes to have obvious defects in homologous chromosome segregation at ATI stage. Thus, these results indicate that Plk1 plays an essential role during the meiosis I/meiosis II transition in porcine oocytes, and the regulation is associated with Plk1's effects on homologous chromosome segregation in the ATI stage.

  5. Nuclear pore complex evolution: a trypanosome Mlp analogue functions in chromosomal segregation but lacks transcriptional barrier activity

    PubMed Central

    Holden, Jennifer M.; Koreny, Ludek; Obado, Samson; Ratushny, Alexander V.; Chen, Wei-Ming; Chiang, Jung-Hsien; Kelly, Steven; Chait, Brian T.; Aitchison, John D.; Rout, Michael P.; Field, Mark C.

    2014-01-01

    The nuclear pore complex (NPC) has dual roles in nucleocytoplasmic transport and chromatin organization. In many eukaryotes the coiled-coil Mlp/Tpr proteins of the NPC nuclear basket have specific functions in interactions with chromatin and defining specialized regions of active transcription, whereas Mlp2 associates with the mitotic spindle/NPC in a cell cycle–dependent manner. We previously identified two putative Mlp-related proteins in African trypanosomes, TbNup110 and TbNup92, the latter of which associates with the spindle. We now provide evidence for independent ancestry for TbNup92/TbNup110 and Mlp/Tpr proteins. However, TbNup92 is required for correct chromosome segregation, with knockout cells exhibiting microaneuploidy and lowered fidelity of telomere segregation. Further, TbNup92 is intimately associated with the mitotic spindle and spindle anchor site but apparently has minimal roles in control of gene transcription, indicating that TbNup92 lacks major barrier activity. TbNup92 therefore acts as a functional analogue of Mlp/Tpr proteins, and, together with the lamina analogue NUP-1, represents a cohort of novel proteins operating at the nuclear periphery of trypanosomes, uncovering complex evolutionary trajectories for the NPC and nuclear lamina. PMID:24600046

  6. The role of meiotic cohesin REC8 in chromosome segregation in gamma irradiation-induced endopolyploid tumour cells.

    PubMed

    Erenpreisa, Jekaterina; Cragg, Mark S; Salmina, Kristine; Hausmann, Michael; Scherthan, Harry

    2009-09-10

    Escape from mitotic catastrophe and generation of endopolyploid tumour cells (ETCs) represents a potential survival strategy of tumour cells in response to genotoxic treatments. ETCs that resume the mitotic cell cycle have reduced ploidy and are often resistant to these treatments. In search for a mechanism for genome reduction, we previously observed that ETCs express meiotic proteins among which REC8 (a meiotic cohesin component) is of particular interest, since it favours reductional cell division in meiosis. In the present investigation, we induced endopolyploidy in p53-dysfunctional human tumour cell lines (Namalwa, WI-L2-NS, HeLa) by gamma irradiation, and analysed the sub-cellular localisation of REC8 in the resulting ETCs. We observed by RT-PCR and Western blot that REC8 is constitutively expressed in these tumour cells, along with SGOL1 and SGOL2, and that REC8 becomes modified after irradiation. REC8 localised to paired sister centromeres in ETCs, the former co-segregating to opposite poles. Furthermore, REC8 localised to the centrosome of interphase ETCs and to the astral poles in anaphase cells where it colocalised with the microtubule-associated protein NuMA. Altogether, our observations indicate that radiation-induced ETCs express features of meiotic cell divisions and that these may facilitate chromosome segregation and genome reduction.

  7. PP2A(Cdc55)'s role in reductional chromosome segregation during achiasmate meiosis in budding yeast is independent of its FEAR function.

    PubMed

    Kerr, Gary W; Wong, Jin Huei; Arumugam, Prakash

    2016-07-26

    PP2A(Cdc55) is a highly conserved serine-threonine protein phosphatase that is involved in diverse cellular processes. In budding yeast, meiotic cells lacking PP2A(Cdc55) activity undergo a premature exit from meiosis I which results in a failure to form bipolar spindles and divide nuclei. This defect is largely due to its role in negatively regulating the Cdc Fourteen Early Anaphase Release (FEAR) pathway. PP2A(Cdc55) prevents nucleolar release of the Cdk (Cyclin-dependent kinase)-antagonising phosphatase Cdc14 by counteracting phosphorylation of the nucleolar protein Net1 by Cdk. CDC55 was identified in a genetic screen for monopolins performed by isolating suppressors of spo11Δ spo12Δ lethality suggesting that Cdc55 might have a role in meiotic chromosome segregation. We investigated this possibility by isolating cdc55 alleles that suppress spo11Δ spo12Δ lethality and show that this suppression is independent of PP2A(Cdc55)'s FEAR function. Although the suppressor mutations in cdc55 affect reductional chromosome segregation in the absence of recombination, they have no effect on chromosome segregation during wild type meiosis. We suggest that Cdc55 is required for reductional chromosome segregation during achiasmate meiosis and this is independent of its FEAR function.

  8. Depletion of a Drosophila homolog of yeast Sup35p disrupts spindle assembly, chromosome segregation, and cytokinesis during male meiosis.

    PubMed

    Basu, J; Williams, B C; Li, Z; Williams, E V; Goldberg, M L

    1998-01-01

    In the course of a genetic screen for male-sterile mutations in Drosophila affecting chromosome segregation during the meiotic divisions in spermatocytes, we identified the mutation dsup35(63D). Examination of mutant testes showed that chromosome misbehavior was a consequence of major disruptions in meiotic spindle assembly. These perturbations included problems in aster formation, separation, and migration around the nuclear envelope; aberrations in spindle organization and integrity; and disappearance of the ana/telophase central spindle, which in turn disrupts cytokinesis. The dsup35(63D) mutation is caused by a P element insertion that affects, specifically in the testis, the expression of a gene (dsup35) encoding the Drosophila homolog of the yeast Sup35p and Xenopus eRF3 proteins. These proteins are involved in the termination of polypeptide synthesis on ribosomes, but previous studies have suggested that Sup35p and closely related proteins of the same family also interact directly with microtubules. An affinity-purified antibody directed against the product of the dsup35 gene was prepared; interestingly, this antibody specifically labels primary spermatocytes in one or two discrete foci of unknown structure within the nucleoplasm. We discuss how depletion of the dsup35 gene product in spermatocytes might lead to the global disruptions in meiotic spindle assembly seen in mutant spermatocytes.

  9. Mps1 Regulates Kinetochore-Microtubule Attachment Stability via the Ska Complex to Ensure Error-Free Chromosome Segregation.

    PubMed

    Maciejowski, John; Drechsler, Hauke; Grundner-Culemann, Kathrin; Ballister, Edward R; Rodriguez-Rodriguez, Jose-Antonio; Rodriguez-Bravo, Veronica; Jones, Mathew J K; Foley, Emily; Lampson, Michael A; Daub, Henrik; McAinsh, Andrew D; Jallepalli, Prasad V

    2017-04-24

    The spindle assembly checkpoint kinase Mps1 not only inhibits anaphase but also corrects erroneous attachments that could lead to missegregation and aneuploidy. However, Mps1's error correction-relevant substrates are unknown. Using a chemically tuned kinetochore-targeting assay, we show that Mps1 destabilizes microtubule attachments (K fibers) epistatically to Aurora B, the other major error-correcting kinase. Through quantitative proteomics, we identify multiple sites of Mps1-regulated phosphorylation at the outer kinetochore. Substrate modification was microtubule sensitive and opposed by PP2A-B56 phosphatases that stabilize chromosome-spindle attachment. Consistently, Mps1 inhibition rescued K-fiber stability after depleting PP2A-B56. We also identify the Ska complex as a key effector of Mps1 at the kinetochore-microtubule interface, as mutations that mimic constitutive phosphorylation destabilized K fibers in vivo and reduced the efficiency of the Ska complex's conversion from lattice diffusion to end-coupled microtubule binding in vitro. Our results reveal how Mps1 dynamically modifies kinetochores to correct improper attachments and ensure faithful chromosome segregation. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Allelic interaction of F1 pollen sterility loci and abnormal chromosome behaviour caused pollen sterility in intersubspecific autotetraploid rice hybrids.

    PubMed

    He, J H; Shahid, M Q; Li, Y J; Guo, H B; Cheng, X A; Liu, X D; Lu, Y G

    2011-08-01

    The intersubspecific hybrids of autotetraploid rice has many features that increase rice yield, but lower seed set is a major hindrance in its utilization. Pollen sterility is one of the most important factors which cause intersubspecific hybrid sterility. The hybrids with greater variation in seed set were used to study how the F(1) pollen sterile loci (S-a, S-b, and S-c) interact with each other and how abnormal chromosome behaviour and allelic interaction of F(1) sterility loci affect pollen fertility and seed set of intersubspecific autotetraploid rice hybrids. The results showed that interaction between pollen sterility loci have significant effects on the pollen fertility of autotetraploid hybrids, and pollen fertility further decreased with an increase in the allelic interaction of F(1) pollen sterility loci. Abnormal ultra-structure and microtubule distribution patterns during pollen mother cell (PMC) meiosis were found in the hybrids with low pollen fertility in interphase and leptotene, suggesting that the effect-time of pollen sterility loci interaction was very early. There were highly significant differences in the number of quadrivalents and bivalents, and in chromosome configuration among all the hybrids, and quadrivalents decreased with an increase in the seed set of autotetraploid hybrids. Many different kinds of chromosomal abnormalities, such as chromosome straggling, chromosome lagging, asynchrony of chromosome disjunction, and tri-fission were found during the various developmental stages of PMC meiosis. All these abnormalities were significantly higher in sterile hybrids than in fertile hybrids, suggesting that pollen sterility gene interactions tend to increase the chromosomal abnormalities which cause the partial abortion of male gametes and leads to the decline in the seed set of the autotetraploid rice hybrids. © 2011 The Author(s).

  11. Arrested human embryos are more likely to have abnormal chromosomes than developing embryos from women of advanced maternal age.

    PubMed

    Qi, Shu-Tao; Liang, Li-Feng; Xian, Ye-Xing; Liu, Jian-Qiao; Wang, Weihua

    2014-01-01

    Aneuploidy is one of the major factors that result in low efficiency in human infertility treatment by in vitro fertilization (IVF). The development of DNA microarray technology allows for aneuploidy screening by analyzing all 23 pairs of chromosomes in human embryos. All chromosome screening for aneuploidy is more accurate than partial chromosome screening, as errors can occur in any chromosome. Currently, chromosome screening for aneuploidy is performed in developing embryos, mainly blastocysts. It has not been performed in arrested embryos and/or compared between developing embryos and arrested embryos from the same IVF cycle. The present study was designed to examine all chromosomes in blastocysts and arrested embryos from the same cycle in patients of advanced maternal ages. Embryos were produced by routine IVF procedures. A total of 90 embryos (45 blastocysts and 45 arrested embryos) from 17 patients were biopsied and analyzed by the Agilent DNA array platform. It was found that 50% of the embryos developed to blastocyst stage; however, only 15.6% of the embryos (both blastocyst and arrested) were euploid, and most (84.4%) of the embryos had chromosomal abnormalities. Further analysis indicated that 28.9% of blastocysts were euploid and 71.1% were aneuploid. By contrast, only one (2.2%) arrested embryo was euploid while others (97.8%) were aneuploid. The prevalence of multiple chromosomal abnormalities in the aneuploid embryos was also higher in the arrested embryos than in the blastocysts. These results indicate that high proportions of human embryos from patients of advanced maternal age are aneuploid, and the arrested embryos are more likely to have abnormal chromosomes than developing embryos.

  12. Karyotypic complexity rather than chromosome 8 abnormalities aggravates the outcome of chronic lymphocytic leukemia patients with TP53 aberrations

    PubMed Central

    Blanco, Gonzalo; Puiggros, Anna; Baliakas, Panagiotis; Athanasiadou, Anastasia; García-Malo, MªDolores; Collado, Rosa; Xochelli, Aliki; Rodríguez-Rivera, María; Ortega, Margarita; Calasanz, Mª José; Luño, Elisa; Vargas, MªTeresa; Grau, Javier; Martínez-Laperche, Carolina; Valiente, Alberto; Cervera, José; Anagnostopoulos, Achilles; Gimeno, Eva; Abella, Eugènia; Stalika, Evangelia; Hernández-Rivas, Jesús Mª; Ortuño, Francisco José; Robles, Diego; Ferrer, Ana; Ivars, David; González, Marcos; Bosch, Francesc; Abrisqueta, Pau; Stamatopoulos, Kostas; Espinet, Blanca

    2016-01-01

    Patients with chronic lymphocytic leukemia (CLL) harboring TP53 aberrations (TP53abs; chromosome 17p deletion and/or TP53 mutation) exhibit an unfavorable clinical outcome. Chromosome 8 abnormalities, namely losses of 8p (8p−) and gains of 8q (8q+) have been suggested to aggravate the outcome of patients with TP53abs. However, the reported series were small, thus hindering definitive conclusions. To gain insight into this issue, we assessed a series of 101 CLL patients harboring TP53 disruption. The frequency of 8p− and 8q+ was 14.7% and 17.8% respectively. Both were associated with a significantly (P < 0.05) higher incidence of a complex karyotype (CK, ≥3 abnormalities) detected by chromosome banding analysis (CBA) compared to cases with normal 8p (N-8p) and 8q (N-8q), respectively. In univariate analysis for 10-year overall survival (OS), 8p− (P = 0.002), 8q+ (P = 0.012) and CK (P = 0.009) were associated with shorter OS. However, in multivariate analysis only CK (HR = 2.47, P = 0.027) maintained independent significance, being associated with a dismal outcome regardless of chromosome 8 abnormalities. In conclusion, our results highlight the association of chromosome 8 abnormalities with CK amongst CLL patients with TP53abs, while also revealing that CK can further aggravate the prognosis of this aggressive subgroup. PMID:27821812

  13. Correlation between CD34 expression and chromosomal abnormalities but not clinical outcome in acute myeloid leukemia.

    PubMed

    Fruchart, C; Lenormand, B; Bastard, C; Boulet, D; Lesesve, J F; Callat, M P; Stamatoullas, A; Monconduit, M; Tilly, H

    1996-11-01

    The hemopoietic stem cell marker CD34 has been reported to be a useful predictor of treatment outcome in acute myeloid leukemia (AML). Previous data suggested that CD34 expression may be associated with other poor prognosis factors in AML such as undifferentiated leukemia, secondary AML (SAML), and clonal abnormalities involving chromosome 5 and 7. In order to analyze the correlations between the clinicopathologic features, cytogenetic and CD34 expression in AML, we retrospectively investigated 99 patients with newly diagnosed AML: 85 with de novo disease and 14 with secondary AML (SAML). Eighty-six patients who received the same induction chemotherapy were available for clinical outcome. Defining a case as positive when > or = 20% of bone marrow cells collected at diagnosis expressed the CD34 antigen, forty-five patients were included in the CD34 positive group. Ninety patients had adequate cytogenetic analysis. Thirty-two patients (72%) with CD34 positive AML exhibited an abnormal karyotype whereas 15 patients (28%) with CD34 negative AML had abnormal metaphases (P < 0.01). Monosomy 7/7q- or monosomy 5/5q- occurred in 10 patients and 8 of them expressed the CD34 antigen (P < 0.05). All patients with t(8;21) which is considered as a favorable factor in AML had levels of CD34 >/= 20% (P < 0.05). We did not find any association between CD34 expression and attainment of complete remission, overall survival, or disease-free survival. In conclusion, the variations of CD34 expression in AML are correlated with cytogenetic abnormalities associated both with poor and favorable outcome. The evaluation of the correlations between CD34 antigen and clinical outcome in AML should take into account the results of pretreatment karyotype.

  14. Characterization of a complex chromosomal rearrangement using chromosome, FISH, and microarray assays in a girl with multiple congenital abnormalities and developmental delay.

    PubMed

    Hemmat, Morteza; Yang, Xiaojing; Chan, Patricia; McGough, Robert A; Ross, Leslie; Mahon, Loretta W; Anguiano, Arturo L; Boris, Wang T; Elnaggar, Mohamed M; Wang, Jia-Chi J; Strom, Charles M; Boyar, Fatih Z

    2014-01-01

    Complex chromosomal rearrangements (CCRs) are balanced or unbalanced structural rearrangements involving three or more cytogenetic breakpoints on two or more chromosomal pairs. The phenotypic anomalies in such cases are attributed to gene disruption, superimposed cryptic imbalances in the genome, and/or position effects. We report a 14-year-old girl who presented with multiple congenital anomalies and developmental delay. Chromosome and FISH analysis indicated a highly complex chromosomal rearrangement involving three chromosomes (3, 7 and 12), seven breakpoints as a result of one inversion, two insertions, and two translocations forming three derivative chromosomes. Additionally, chromosomal microarray study (CMA) revealed two submicroscopic deletions at 3p12.3 (467 kb) and 12q13.12 (442 kb). We postulate that microdeletion within the ROBO1 gene at 3p12.3 may have played a role in the patient's developmental delay, since it has potential activity-dependent role in neurons. Additionally, factors other than genomic deletions such as loss of function or position effects may also contribute to the abnormal phenotype in our patient.

  15. Characterization of a complex chromosomal rearrangement using chromosome, FISH, and microarray assays in a girl with multiple congenital abnormalities and developmental delay

    PubMed Central

    2014-01-01

    Complex chromosomal rearrangements (CCRs) are balanced or unbalanced structural rearrangements involving three or more cytogenetic breakpoints on two or more chromosomal pairs. The phenotypic anomalies in such cases are attributed to gene disruption, superimposed cryptic imbalances in the genome, and/or position effects. We report a 14-year-old girl who presented with multiple congenital anomalies and developmental delay. Chromosome and FISH analysis indicated a highly complex chromosomal rearrangement involving three chromosomes (3, 7 and 12), seven breakpoints as a result of one inversion, two insertions, and two translocations forming three derivative chromosomes. Additionally, chromosomal microarray study (CMA) revealed two submicroscopic deletions at 3p12.3 (467 kb) and 12q13.12 (442 kb). We postulate that microdeletion within the ROBO1 gene at 3p12.3 may have played a role in the patient’s developmental delay, since it has potential activity-dependent role in neurons. Additionally, factors other than genomic deletions such as loss of function or position effects may also contribute to the abnormal phenotype in our patient. PMID:25478007

  16. First-trimester screening for chromosomal abnormalities: advantages of an instant results approach.

    PubMed

    Norton, Mary E

    2010-09-01

    Protocols that include first trimester screening for fetal chromosome abnormalities have become standard of care throughout the United States. Earlier screening allows for first trimester diagnostic testing in cases found to be at increased risk. However, first trimester screening requires coordination of the nuchal translucency ultrasound screening (NT) and biochemical screening, during early, specific, narrow, but slightly different gestational age ranges. Instant results can often be provided at the time of the NT ultrasound if preceded by the programs that perform the biochemical analyses; this optimizes the benefits of the first trimester approach while improving efficiency and communication with the patient. This article discusses the benefits and logistics of such an approach. Copyright 2010 Elsevier Inc. All rights reserved.

  17. Nuclear abnormalities in aspirated thyroid cells and chromosome aberrations in lymphocytes of residents near the Semipalatinsk nuclear test site.

    PubMed

    Takeichi, Nobuo; Hoshi, Masaharu; Iida, Shozo; Tanaka, Kimio; Harada, Yuka; Zhumadilov, Zhaxybay; Chaizhunusova, Nailya; Apsalikov, Kazbek N; Noso, Yoshihiro; Inaba, Toshiya; Tanaka, Kenichi; Endo, Satoru

    2006-02-01

    Chromosomal studies in peripheral lymphocytes from 63 residents near the Semipalatinsk nuclear test site, at ages of 52-63 years old, were performed in 2001-2002. A higher rate of chromosome aberrations was observed in the two contaminated villages, Dolon and Sarjal, compared with the control village, Kokpekti. Moreover, a relationship of frequency of cells with radiation induced chromosome aberrations and the previously estimated exposure dose was observed. Furthermore, apparent nuclear abnormalities (ANA) of thyroid follicular cells were studied in 30 out of 63 residents, who were examined for chromosome aberrations. A higher rate of ANA was also found in the residents in the exposed villages compared with those in the control village. These results suggest radiation effects both on the chromosomes in peripheral lymphocytes and on the follicular cells in the thyroid.

  18. Dynamics of tobacco DNA topoisomerases II in cell cycle regulation: to manage topological constrains during replication, transcription and mitotic chromosome condensation and segregation.

    PubMed

    Singh, Badri Nath; Achary, V Mohan Murali; Panditi, Varakumar; Sopory, Sudhir K; Reddy, Malireddy K

    2017-08-01

    The topoisomerase II expression varies as a function of cell proliferation. Maximal topoisomerase II expression was tightly coupled to S phase and G2/M phase via both transcriptional and post-transcriptional regulation. Investigation in meiosis using pollen mother cells also revealed that it is not the major component of meiotic chromosomes, it seems to diffuse out once meiotic chromosomal condensation is completed. Synchronized tobacco BY-2 cell cultures were used to study the role of topoisomerase II in various stages of the cell cycle. Topoisomerase II transcript accumulation was observed during the S- and G2/M- phase of cell cycle. This biphasic expression pattern indicates the active requirement of topoisomerase II during these stages of the cell cycle. Through immuno-localization of topoisomerase II was observed diffusely throughout the nucleoplasm in interphase nuclei, whereas, the nucleolus region exhibited a more prominent immuno-positive staining that correlated with rRNA transcription, as shown by propidium iodide staining and BrUTP incorporation. The immuno-staining analysis also showed that topoisomerase II is the major component of mitotic chromosomes and remain attached to the chromosomes during cell division. The inhibition of topoisomerase II activity using specific inhibitors revealed quite dramatic effect on condensation of chromatin and chromosome individualization from prophase to metaphase transition. Partially condensed chromosomes were not arranged on metaphase plate and chromosomal perturbations were observed when advance to anaphase, suggesting the importance of topoisomerase II activity for proper chromosome condensation and segregation during mitosis. Contrary, topoisomerase II is not the major component of meiotic chromosomes, even though mitosis and meiosis share many processes, including the DNA replication, chromosome condensation and precisely regulated partitioning of chromosomes into daughter cells. Even if topoisomerase II is

  19. Abnormally banded chromosomal regions in doxorubicin-resistant B16-BL6 murine melanoma cells.

    PubMed

    Slovak, M L; Hoeltge, G A; Ganapathi, R

    1986-08-01

    B16-BL6 murine melanoma cells were selected for cytogenetic evaluation during the stepwise development of increasing resistance in vitro to the antitumor antibiotic, doxorubicin (DOX). Karyotypic studies demonstrated extensive heteroploidy with both numerical and structural abnormalities which were not present in the parental DOX-sensitive B16-BL6 cells. Trypsin-Giemsa banding revealed the presence of several marker chromosomes containing abnormally banding regions (ABRs) in the 44-fold B16-BL6 DOX-resistant subline. These ABRs appeared to be more homogeneously staining at the higher DOX concentrations. Length measurements (ABR index) in seven banded metaphases indicated a direct correlation with increasing DOX concentration. When the DOX-resistant cells were grown in drug-free medium for 1 yr, the drug-resistant phenotype gradually declined in parallel with the level of resistance and the ABR index. DOX-induced cytogenetic damage examined by sister chromatid exchange methodology in parental B16-BL6 cells indicated a linear sister chromatid exchange:DOX dose-response relationship. However, after continuous treatment of parental B16-BL6 cells with DOX (0.01 microgram/ml) for 30 days, sister chromatid exchange scores were found to return to base-line values. The B16-BL6 resistant cells demonstrated a cross-resistant phenotype with N-trifluoroacetyladriamycin-14-valerate, actinomycin D, and the Vinca alkaloids but not with 1-beta-D-arabinofuranosylcytosine. The results suggest that ABR-containing chromosomes in DOX-resistant sublines may represent cytogenetic alterations of specific amplified genes involved in the expression of DOX resistance. Further studies are required to identify and define the possible gene products and to correlate their relationship to the cytotoxic action of doxorubicin.

  20. A Dominantly Acting Murine Allele of Mcm4 Causes Chromosomal Abnormalities and Promotes Tumorigenesis

    PubMed Central

    Bagley, Bruce N.; Keane, Thomas M.; Maklakova, Vilena I.; Marshall, Jonathon G.; Lester, Rachael A.; Cancel, Michelle M.; Paulsen, Alex R.; Bendzick, Laura E.; Been, Raha A.; Kogan, Scott C.; Cormier, Robert T.; Kendziorski, Christina; Adams, David J.; Collier, Lara S.

    2012-01-01

    Here we report the isolation of a murine model for heritable T cell lymphoblastic leukemia/lymphoma (T-ALL) called Spontaneous dominant leukemia (Sdl). Sdl heterozygous mice develop disease with a short latency and high penetrance, while mice homozygous for the mutation die early during embryonic development. Sdl mice exhibit an increase in the frequency of micronucleated reticulocytes, and T-ALLs from Sdl mice harbor small amplifications and deletions, including activating deletions at the Notch1 locus. Using exome sequencing it was determined that Sdl mice harbor a spontaneously acquired mutation in Mcm4 (Mcm4D573H). MCM4 is part of the heterohexameric complex of MCM2–7 that is important for licensing of DNA origins prior to S phase and also serves as the core of the replicative helicase that unwinds DNA at replication forks. Previous studies in murine models have discovered that genetic reductions of MCM complex levels promote tumor formation by causing genomic instability. However, Sdl mice possess normal levels of Mcms, and there is no evidence for loss-of-heterozygosity at the Mcm4 locus in Sdl leukemias. Studies in Saccharomyces cerevisiae indicate that the Sdl mutation produces a biologically inactive helicase. Together, these data support a model in which chromosomal abnormalities in Sdl mice result from the ability of MCM4D573H to incorporate into MCM complexes and render them inactive. Our studies indicate that dominantly acting alleles of MCMs can be compatible with viability but have dramatic oncogenic consequences by causing chromosomal abnormalities. PMID:23133403

  1. A dominantly acting murine allele of Mcm4 causes chromosomal abnormalities and promotes tumorigenesis.

    PubMed

    Bagley, Bruce N; Keane, Thomas M; Maklakova, Vilena I; Marshall, Jonathon G; Lester, Rachael A; Cancel, Michelle M; Paulsen, Alex R; Bendzick, Laura E; Been, Raha A; Kogan, Scott C; Cormier, Robert T; Kendziorski, Christina; Adams, David J; Collier, Lara S

    2012-01-01

    Here we report the isolation of a murine model for heritable T cell lymphoblastic leukemia/lymphoma (T-ALL) called Spontaneous dominant leukemia (Sdl). Sdl heterozygous mice develop disease with a short latency and high penetrance, while mice homozygous for the mutation die early during embryonic development. Sdl mice exhibit an increase in the frequency of micronucleated reticulocytes, and T-ALLs from Sdl mice harbor small amplifications and deletions, including activating deletions at the Notch1 locus. Using exome sequencing it was determined that Sdl mice harbor a spontaneously acquired mutation in Mcm4 (Mcm4(D573H)). MCM4 is part of the heterohexameric complex of MCM2-7 that is important for licensing of DNA origins prior to S phase and also serves as the core of the replicative helicase that unwinds DNA at replication forks. Previous studies in murine models have discovered that genetic reductions of MCM complex levels promote tumor formation by causing genomic instability. However, Sdl mice possess normal levels of Mcms, and there is no evidence for loss-of-heterozygosity at the Mcm4 locus in Sdl leukemias. Studies in Saccharomyces cerevisiae indicate that the Sdl mutation produces a biologically inactive helicase. Together, these data support a model in which chromosomal abnormalities in Sdl mice result from the ability of MCM4(D573H) to incorporate into MCM complexes and render them inactive. Our studies indicate that dominantly acting alleles of MCMs can be compatible with viability but have dramatic oncogenic consequences by causing chromosomal abnormalities.

  2. Disappearance of enlarged nuchal translucency before 14 weeks' gestation: relationship with chromosomal abnormalities and pregnancy outcome.

    PubMed

    Müller, M A; Pajkrt, E; Bleker, O P; Bonsel, G J; Bilardo, C M

    2004-08-01

    The aim of this study was to investigate the natural course of enlarged nuchal translucency (NT) and to determine if its disappearance before 14 weeks' gestation is a favorable prognostic sign in relation to fetal karyotype and pregnancy outcome. A total of 147 women with increased NT (> 95th centile) at first measurement were included in this study. A second measurement was performed in all cases, at an interval of at least 2 days. Both measurements were taken between 10 + 3 and 14 + 0 weeks. All women underwent chorionic villus sampling or amniocentesis for subsequent karyotyping. In those women with a normal karyotype, a fetal anomaly scan was performed at 20 weeks' gestation. Pregnancy outcome was recorded in all cases. The finding of persistent or disappearing NT enlargement was analyzed in relation to fetal karyotype and pregnancy outcome. Of the 147 paired measurements, NT remained enlarged at the second measurement in 121 (82%) cases. An abnormal karyotype was found in 35% of these cases. In 26 (18%) fetuses the NT measurement was found to be below the 95th percentile at the second measurement and in only two of them an abnormal karyotype was found (8%). In the 103 chromosomally normal fetuses an adverse outcome (i.e. fetal loss or structural defects) was recorded in 22 fetuses with persistent enlargement (28%) and in four fetuses with disappearing enlargement (17%). Disappearance of an enlarged NT before 14 weeks' gestation is not a rare phenomenon and seems to be a favorable prognostic sign with respect to fetal karyotype. Overall, no significant difference in pregnancy outcome was found between chromosomally normal fetuses with persisting or disappearing NT enlargement. Copyright 2004 ISUOG

  3. Down syndrome-associated haematopoiesis abnormalities created by chromosome transfer and genome editing technologies.

    PubMed

    Kazuki, Yasuhiro; Yakura, Yuwna; Abe, Satoshi; Osaki, Mitsuhiko; Kajitani, Naoyo; Kazuki, Kanako; Takehara, Shoko; Honma, Kazuhisa; Suemori, Hirofumi; Yamazaki, Satoshi; Sakuma, Tetsushi; Toki, Tsutomu; Shimizu, Ritsuko; Nakauchi, Hiromitsu; Yamamoto, Takashi; Oshimura, Mitsuo

    2014-08-27

    Infants with Down syndrome (DS) are at a high risk of developing transient abnormal myelopoiesis (TAM). A GATA1 mutation leading to the production of N-terminally truncated GATA1 (GATA1s) in early megakaryocyte/erythroid progenitors is linked to the onset of TAM and cooperated with the effect of trisomy 21 (Ts21). To gain insights into the underlying mechanisms of the progression to TAM in DS patients, we generated human pluripotent stem cells harbouring Ts21 and/or GATA1s by combining microcell-mediated chromosome transfer and genome editing technologies. In vitro haematopoietic differentiation assays showed that the GATA1s mutation blocked erythropoiesis irrespective of an extra chromosome 21, while Ts21 and the GATA1s mutation independently perturbed megakaryopoiesis and the combination of Ts21 and the GATA1s mutation synergistically contributed to an aberrant accumulation of skewed megakaryocytes. Thus, the DS model cells generated by these two technologies are useful in assessing how GATA1s mutation is involved in the onset of TAM in patients with DS.

  4. Simultaneous regression of Philadelphia chromosome and multiple nonrecurrent clonal chromosomal abnormalities with imatinib mesylate in a patient autografted 22 years before for chronic myelogenous leukemia.

    PubMed

    Van Den Akker, J; Coppo, P; Portnoï, M F; Barbu, V; Bories, D; Gorin, N C

    2007-09-01

    A 31-year-old patient developed chronic myelogenous leukemia (CML) in November, 1983. In November 1984, following a diagnosis of acceleration, he received an autologous hemopoietic transplant after conditioning with cyclophosphamide and total body irradiation. The autologous marrow was purged with mafosfamide. Over 20 years, the patient remained in chronic phase of CML. Multiple nonrecurrent clonal chromosomal abnormalities appeared leading to a very complex karyotype, including among others involvement of chromosomes 1, 7, 9, 13, 19, and X. Fluorescent in situ hybridization showed that the two chromosomes 9 were involved. Acute myeloid crisis was diagnosed in February, 2004. Treatment with imatinib mesylate resulted within 6 months in a total disappearance of all chromosomal abnormalities with a complete cytogenetic and molecular response, which persists 3 years later. We question whether the ex vivo purging procedure with mafosfamide has favored the occurrence of these particular cytogenetic abnormalities (with no independent oncogenic potential) within the original leukemic stem cell pool. It remains unclear whether the autologous transplantation has indeed resulted into some prolongation of the duration of the chronic phase, which lasted for 20 years. At time of acute crisis, the dramatic response to imatinib mesylate leading to a complete cytogenetic and molecular response is noteworthy.

  5. Sequential Cross-Species Chromosome Painting among River Buffalo, Cattle, Sheep and Goat: A Useful Tool for Chromosome Abnormalities Diagnosis within the Family Bovidae

    PubMed Central

    Pauciullo, Alfredo; Perucatti, Angela; Cosenza, Gianfranco; Iannuzzi, Alessandra; Incarnato, Domenico; Genualdo, Viviana; Di Berardino, Dino; Iannuzzi, Leopoldo

    2014-01-01

    The main goal of this study was to develop a comparative multi-colour Zoo-FISH on domestic ruminants metaphases using a combination of whole chromosome and sub-chromosomal painting probes obtained from the river buffalo species (Bubalus bubalis, 2n = 50,XY). A total of 13 DNA probes were obtained through chromosome microdissection and DOP-PCR amplification, labelled with two fluorochromes and sequentially hybridized on river buffalo, cattle (Bos taurus, 2n = 60,XY), sheep (Ovis aries, 2n = 54,XY) and goat (Capra hircus, 2n = 60,XY) metaphases. The same set of paintings were then hybridized on bovine secondary oocytes to test their potential use for aneuploidy detection during in vitro maturation. FISH showed excellent specificity on metaphases and interphase nuclei of all the investigated species. Eight pairs of chromosomes were simultaneously identified in buffalo, whereas the same set of probes covered 13 out 30 chromosome pairs in the bovine and goat karyotypes and 40% of the sheep karyotype (11 out of 27 chromosome pairs). This result allowed development of the first comparative M-FISH karyotype within the domestic ruminants. The molecular resolution of complex karyotypes by FISH is particularly useful for the small chromosomes, whose similarity in the banding patterns makes their identification very difficult. The M-FISH karyotype also represents a practical tool for structural and numerical chromosome abnormalities diagnosis. In this regard, the successful hybridization on bovine secondary oocytes confirmed the potential use of this set of probes for the simultaneous identification on the same germ cell of 12 chromosome aneuploidies. This is a fundamental result for monitoring the reproductive health of the domestic animals in relation to management errors and/or environmental hazards. PMID:25330006

  6. Amniotic fluid-AFP in Down syndrome and other chromosome abnormalities.

    PubMed

    Crandall, B F; Matsumoto, M; Perdue, S

    1988-05-01

    80.2 Per cent of 111 Down syndrome pregnancies had anmiotic fluid (AF) alpha fetoprotein (AFP) levels on or below the median and 10.8 per cent at or below 0.5 MoM compared with 41.9 and 1.4 per cent of controls. These differences were even more striking when the gestational age was less than 18 weeks compared with greater than or equal to 18 weeks. No such association was seen for other chromosome abnormalities including trisomy 18,45,X and mosaics, 47,XXY,47,XXX, and other structural abnormalities and triploidy, even when high levels due to defects such as omphalocele and cystic hygroma were excluded. All cases of trisomy 13 and 80 per cent with 47,XYY had AF-AFP levels above the median. Selection of cases for karyotyping by a low level of AF-AFP would clearly fail to detect aneuploidies other than Down syndrome and is not recommended. A possible weak association between low maternal serum (MS) and AF-AFPs in Down syndrome was most evident at less than 18 weeks, suggesting that MS screening between 16 and 18 weeks may be the most informative time.

  7. Sequencing chromosomal abnormalities reveals neurodevelopmental loci that confer risk across diagnostic boundaries

    PubMed Central

    Talkowski, Michael E.; Rosenfeld, Jill A.; Blumenthal, Ian; Pillalamarri, Vamsee; Chiang, Colby; Heilbut, Adrian; Ernst, Carl; Hanscom, Carrie; Rossin, Elizabeth; Lindgren, Amelia; Pereira, Shahrin; Ruderfer, Douglas; Kirby, Andrew; Ripke, Stephan; Harris, David; Lee, Ji-Hyun; Ha, Kyungsoo; Kim, Hyung-Goo; Solomon, Benjamin D.; Gropman, Andrea L.; Lucente, Diane; Sims, Katherine; Ohsumi, Toshiro K.; Borowsky, Mark L.; Loranger, Stephanie; Quade, Bradley; Lage, Kasper; Miles, Judith; Wu, Bai-Lin; Shen, Yiping; Neale, Benjamin; Shaffer, Lisa G.; Daly, Mark J.; Morton, Cynthia C.; Gusella, James F.

    2012-01-01

    SUMMARY Balanced chromosomal abnormalities (BCAs) represent a reservoir of single gene disruptions in neurodevelopmental disorders (NDD). We sequenced BCAs in autism and related NDDs, revealing disruption of 33 loci in four general categories: 1) genes associated with abnormal neurodevelopment (e.g., AUTS2, FOXP1, CDKL5), 2) single gene contributors to microdeletion syndromes (MBD5, SATB2, EHMT1, SNURF-SNRPN), 3) novel risk loci (e.g., CHD8, KIRREL3, ZNF507), and 4) genes associated with later onset psychiatric disorders (e.g., TCF4, ZNF804A, PDE10A, GRIN2B, ANK3). We also discovered profoundly increased burden of copy number variants among 19,556 neurodevelopmental cases compared to 13,991 controls (p = 2.07×10−47) and enrichment of polygenic risk alleles from autism and schizophrenia genome-wide association studies (p = 0.0018 and 0.0009, respectively). Our findings suggest a polygenic risk model of autism incorporating loci of strong effect and indicate that some neurodevelopmental genes are sensitive to perturbation by multiple mutational mechanisms, leading to variable phenotypic outcomes that manifest at different life stages. PMID:22521361

  8. Multifunctional centromere binding factor 1 is essential for chromosome segregation in the human pathogenic yeast Candida glabrata.

    PubMed

    Stoyan, T; Gloeckner, G; Diekmann, S; Carbon, J

    2001-08-01

    The CBF1 (centromere binding factor 1) gene of Candida glabrata was cloned by functional complementation of the methionine biosynthesis defect of a Saccharomyces cerevisiae cbf1 deletion mutant. The C. glabrata-coded protein, CgCbf1, contains a basic-helix-loop-helix leucine zipper domain and has features similar to those of other budding yeast Cbf1 proteins. CgCbf1p binds in vitro to the centromere DNA element I (CDEI) sequence GTCACATG with high affinity (0.9 x 10(9) M(-1)). Bandshift experiments revealed a pattern of protein-DNA complexes on CgCEN DNA different from that known for S. cerevisiae. We examined the effect of altering the CDEI binding site on CEN plasmid segregation, using a newly developed colony-sectoring assay. Internal deletion of the CDEI binding site led only to a fivefold increase in rates of plasmid loss, indicating that direct binding of Cbf1p to the centromere DNA is not required for full function. Additional deletion of sequences to the left of CDEI, however, led to a 70-fold increase in plasmid loss rates. Deletion of the CBF1 gene proved to be lethal in C. glabrata. C. glabrata cells containing the CBF1 gene under the influence of a shutdown promoter (tetO-ScHOP) arrested their growth after 5 h of cultivation in the presence of the reactive drug doxycycline. DAPI (4',6'-diamidino-2-phenylindole) staining of the arrested cells revealed a significant increase in the number of large-budded cells with single nuclei, 2C DNA content, and short spindles, indicating a defect in the G(2)/M transition of the cell cycle. Thus, we conclude that Cbf1p is required for chromosome segregation in C. glabrata.

  9. CDC-48/p97 is required for proper meiotic chromosome segregation via controlling AIR-2/Aurora B kinase localization in Caenorhabditis elegans.

    PubMed

    Sasagawa, Yohei; Higashitani, Atsushi; Urano, Takeshi; Ogura, Teru; Yamanaka, Kunitoshi

    2012-08-01

    CDC-48/p97 is a AAA (ATPases associated with diverse cellular activities) chaperone involved in protein conformational changes such as the disassembly of protein complexes. We previously reported that Caenorhabditis elegans CDC-48.1 and CDC-48.2 (CDC-48s) are essential for the progression of meiosis I metaphase. Here, we report that CDC-48s are required for proper chromosome segregation during meiosis in C. elegans. In wild-type worms, at the diakinesis phase, phosphorylation of histone H3, one of the known substrates of aurora B kinase (AIR-2), on meiosis I chromatids correlated with AIR-2 localization at the cohesion sites of homologous chromatids. Conversely, depletion of CDC-48s resulted in a significant expansion of signals for AIR-2 and phosphorylated histone H3 over the entire length of meiotic chromosomes, leading to defective chromosome segregation, while the total amount of AIR-2 in lysates was not changed by the depletion of CDC-48s. The defective segregation of meiotic chromosomes caused by the depletion of CDC-48s was suppressed by the simultaneous depletion of AIR-2 and is similar to that observed following the depletion of protein phosphatase 1 (PP1) phosphatases. However, the amount and localization of PP1 were not changed by the depletion of CDC-48s. These results suggest that CDC-48s control the restricted localization of AIR-2 to the cohesion sites of homologous chromatids in meiosis I. Copyright © 2012 Elsevier Inc. All rights reserved.

  10. Chromosome

    MedlinePlus

    ... St Louis, MO: Elsevier; 2017:chap 69. Taber's Medical Dictionary Online. Chromosome. www.tabers.com/tabersonline/view/Tabers-Dictionary/753321/all/chromosome?q=Chromosome&ti=0 . Accessed June 11, 2017.

  11. Decision to abort after a prenatal diagnosis of sex chromosome abnormality: a systematic review of the literature.

    PubMed

    Jeon, Kwon Chan; Chen, Lei-Shih; Goodson, Patricia

    2012-01-01

    We performed a systematic review of factors affecting parental decisions to continue or terminate a pregnancy after prenatal diagnosis of a sex chromosome abnormality, as reported in published studies from 1987 to May 2011. Based on the Matrix Method for systematic reviews, 19 studies were found in five electronic databases, meeting specific inclusion/exclusion criteria. Abstracted data were organized in a matrix. Alongside the search for factors influencing parental decisions, each study was judged on its methodological quality and assigned a methodological quality score. Decisions either to terminate or to continue a sex chromosome abnormality-affected pregnancy shared five similar factors: specific type of sex chromosome abnormality, gestational week at diagnosis, parents' age, providers' genetic expertise, and number of children/desire for (more) children. Factors unique to termination decisions included parents' fear/anxiety and directive counseling. Factors uniquely associated with continuation decisions were parents' socioeconomic status and ethnicity. The studies' average methodological quality score was 10.6 (SD = 1.67; range, 8-14). Findings from this review can be useful in adapting and modifying guidelines for genetic counseling after prenatal diagnosis of a sex chromosome abnormality. Moreover, improving the quality of future studies on this topic may allow clearer understanding of the most influential factors affecting parental decisions.

  12. [Characteristics of pregnancy and delivery of fetuses affected by either central nervous system malformations or chromosomal abnormalities].

    PubMed

    Friedler, Jordana Mashiach; Mazor, Moshe; Shoham-Vardi, Ilana; Bashiri, Asher

    2011-11-01

    To determine whether fetuses affected by either chromosomal abnormalities or central nervous system (CNS) malformations are prone to complications during pregnancy and delivery. In this study, 320 singleton pregnancies with CNS malformations and 133 singleton pregnancies with chromosomal abnormaLities were compared with 149,112 singleton births without any known congenital anomalies. Exclusion criteria were: births with other congenital anomalies or malformations, pregnancies Lacking prenatal care and multiple pregnancies. Data was obtained using the computerized birth discharge records. The statistical analysis was performed with the SPSS package. There were no statistically significant differences in maternal age, ethnicity, uterine anomalies or parity. The ratio of general anesthesia was almost double in the study groups compared to the control group: 25% in the CNS malformation group (RR 2.617, CI 2.031-3.372) and 25.6% in the chromosomal abnormality group (RR 2.696, CI 1.825-3.982) and 11.3% in the control group (p < 0.001). There were nearly double cesarean sections (CS) rates in both study groups: 21.5% in the CNS malformation group, 20.3% in the chromosomal abnormaLity group and 12% in the control group. A logistic regression model that included previous CS, maLpresentation, non-reassuring fetal heart monitor (NRFHR) and presence of a malformation, concluded that the presence of a malformation was not an independent risk factor for CS. However, indirect causes, such as malpresentation (4.34 OR), were independently associated with the malformations. Fetuses affected by either CNS malformations or chromosomal abnormalities have a higher rate of pregnancy and delivery complications, including those which increase the risk of maternal morbidity and mortality.

  13. Associations of recurrent miscarriages with chromosomal abnormalities, thrombophilia allelic polymorphisms and/or consanguinity in Saudi Arabia.

    PubMed

    Turki, Rola F; Assidi, Mourad; Banni, Huda A; Zahed, Hanan A; Karim, Sajjad; Schulten, Hans-Juergen; Abu-Elmagd, Muhammad; Rouzi, Abdulrahim A; Bajouh, Osama; Jamal, Hassan S; Al-Qahtani, Mohammed H; Abuzenadah, Adel M

    2016-10-10

    Recurrent pregnancy loss (RPL) or recurrent spontaneous abortion is an obstetric complication that affects couples at reproductive age. Previous reports documented a clear relationship between parents with chromosomal abnormalities and both recurrent miscarriages and infertility. However, limited data is available from the Arabian Peninsula which is known by higher rates of consanguineous marriages. The main goal of this study was to determine the prevalence of chromosomal abnormalities and thrombophilic polymorphisms, and to correlate them with RPL and consanguinity in Saudi Arabia. Cytogenetic analysis of 171 consent patients with RPL was performed by the standard method of 72-h lymphocyte culture and GTG banding. Allelic polymorphisms of three thrombophilic genes (Factor V Leiden, Prothrombin A20210G, MTHFR C677T) were performed using PCR-RFLP (restriction fragment length polymorphism) and gel electrophoresis. Data analysis revealed that 7.6 % of patients were carrier of numerical or structural chromosomal abnormalities. A high rate of translocations (46 %) was associated to increased incidence of RPL. A significant correlation between consanguineous RPL patients and chromosomal abnormalities (P < 0.05) was found. Both Factor V Leiden and Prothrombin A20210G allelic polymorphisms were significantly associated with a higher prevalence of RPL. This study demonstrated a strong association between RPL and the prevalence of chromosomal abnormalities and inherited thrombophilia. Given the high rate of consanguineous marriages in the Saudi population, these results underline the importance of systematic cytogenetic investigation and genetic counseling preferably at the premarital stage or at least during early pregnancy phase through preimplantation genetic diagnosis (PGD).

  14. Preliminary analysis of numerical chromosome abnormalities in reciprocal and Robertsonian translocation preimplantation genetic diagnosis cases with 24-chromosomal analysis with an aCGH/SNP microarray.

    PubMed

    Xie, Yanxin; Xu, Yanwen; Wang, Jing; Miao, Benyu; Zeng, Yanhong; Ding, Chenhui; Gao, Jun; Zhou, Canquan

    2018-01-01

    The aim of this study was to determine whether an interchromosomal effect (ICE) occurred in embryos obtained from reciprocal translocation (rcp) and Robertsonian translocation (RT) carriers who were following a preimplantation genetic diagnosis (PGD) with whole chromosome screening with an aCGH and SNP microarray. We also analyzed the chromosomal numerical abnormalities in embryos with aneuploidy in parental chromosomes that were not involved with a translocation and balanced in involved parental translocation chromosomes. This retrospective study included 832 embryos obtained from rcp carriers and 382 embryos from RT carriers that were biopsied in 139 PGD cycles. The control group involved embryos obtained from age-matched patient karyotypes who were undergoing preimplantation genetic screening (PGS) with non-translocation, and 579 embryos were analyzed in the control group. A single blastomere at the cleavage stage or trophectoderm from a blastocyst was biopsied, and 24-chromosomal analysis with an aCGH/SNP microarray was conducted using the PGD/PGS protocols. Statistical analyses were implemented on the incidences of cumulative aneuploidy rates between the translocation carriers and the control group. Reliable results were obtained from 138 couples, among whom only one patient was a balanced rcp or RT translocation carrier, undergoing PGD testing in our center from January 2012 to June 2014. For day 3 embryos, the aneuploidy rates were 50.7% for rcp carriers and 49.1% for RT carriers, compared with the control group, with 44.8% at a maternal age < 36 years. When the maternal age was ≥ 36 years, the aneuploidy rates were increased to 61.1% for rcp carriers, 56.7% for RT carriers, and 60.3% for the control group. There were no significant differences. In day 5 embryos, the aneuploidy rates were 24.5% for rcp carriers and 34.9% for RT carriers, compared with the control group with 53.6% at a maternal age < 36 years. When the maternal age was ≥ 36

  15. Abnormal neurofilament inclusions and segregations in dorsal root ganglia of a Charcot-Marie-Tooth type 2E mouse model.

    PubMed

    Zhao, Jian; Brown, Kristy; Liem, Ronald K H

    2017-01-01

    Charcot-Marie-Tooth (CMT) disease or hereditary motor and sensory neuropathy is the most prevalent inherited peripheral neuropathy and is associated with over 90 causative genes. Mutations in neurofilament light polypeptide gene, NEFL cause CMT2E, an axonal form of CMT that results in abnormal structures and/or functions of peripheral axons in spinal cord motor neurons and dorsal root ganglion neurons. We have previously generated and characterized a knock-in mouse model of CMT2E with the N98S mutation in Nefl that presented with multiple inclusions in spinal cord neurons. In this report, we conduct immunofluorescence studies of cultured dorsal root ganglia (DRG) from NeflN98S/+ mice, and show that inclusions found in DRG neurites can occur in embryonic stages. Ultrastructural analyses reveal that the inclusions are disordered neurofilaments packed in high density, segregated from other organelles. Immunochemical studies show decreased NFL protein levels in DRG, cerebellum and spinal cord in NeflN98S/+ mice, and total NFL protein pool is shifted toward the triton-insoluble fraction. Our findings reveal the nature of the inclusions in NeflN98S/+ mice, provide useful information to understand mechanisms of CMT2E disease, and identify DRG from NeflN98S/+ mice as a useful cell line model for therapeutic discoveries.

  16. Mitotic Spindle Defects and Chromosome Mis-Segregation Induced by LDL/Cholesterol—Implications for Niemann-Pick C1, Alzheimer’s Disease, and Atherosclerosis

    PubMed Central

    Granic, Antoneta; Potter, Huntington

    2013-01-01

    Elevated low-density lipoprotein (LDL)-cholesterol is a risk factor for both Alzheimer’s disease (AD) and Atherosclerosis (CVD), suggesting a common lipid-sensitive step in their pathogenesis. Previous results show that AD and CVD also share a cell cycle defect: chromosome instability and up to 30% aneuploidy–in neurons and other cells in AD and in smooth muscle cells in atherosclerotic plaques in CVD. Indeed, specific degeneration of aneuploid neurons accounts for 90% of neuronal loss in AD brain, indicating that aneuploidy underlies AD neurodegeneration. Cell/mouse models of AD develop similar aneuploidy through amyloid-beta (Aß) inhibition of specific microtubule motors and consequent disruption of mitotic spindles. Here we tested the hypothesis that, like upregulated Aß, elevated LDL/cholesterol and altered intracellular cholesterol homeostasis also causes chromosomal instability. Specifically we found that: 1) high dietary cholesterol induces aneuploidy in mice, satisfying the hypothesis’ first prediction, 2) Niemann-Pick C1 patients accumulate aneuploid fibroblasts, neurons, and glia, demonstrating a similar aneugenic effect of intracellular cholesterol accumulation in humans 3) oxidized LDL, LDL, and cholesterol, but not high-density lipoprotein (HDL), induce chromosome mis-segregation and aneuploidy in cultured cells, including neuronal precursors, indicating that LDL/cholesterol directly affects the cell cycle, 4) LDL-induced aneuploidy requires the LDL receptor, but not Aß, showing that LDL works differently than Aß, with the same end result, 5) cholesterol treatment disrupts the structure of the mitotic spindle, providing a cell biological mechanism for its aneugenic activity, and 6) ethanol or calcium chelation attenuates lipoprotein-induced chromosome mis-segregation, providing molecular insights into cholesterol’s aneugenic mechanism, specifically through its rigidifying effect on the cell membrane, and potentially explaining why ethanol

  17. Mitotic spindle defects and chromosome mis-segregation induced by LDL/cholesterol-implications for Niemann-Pick C1, Alzheimer's disease, and atherosclerosis.

    PubMed

    Granic, Antoneta; Potter, Huntington

    2013-01-01

    Elevated low-density lipoprotein (LDL)-cholesterol is a risk factor for both Alzheimer's disease (AD) and Atherosclerosis (CVD), suggesting a common lipid-sensitive step in their pathogenesis. Previous results show that AD and CVD also share a cell cycle defect: chromosome instability and up to 30% aneuploidy-in neurons and other cells in AD and in smooth muscle cells in atherosclerotic plaques in CVD. Indeed, specific degeneration of aneuploid neurons accounts for 90% of neuronal loss in AD brain, indicating that aneuploidy underlies AD neurodegeneration. Cell/mouse models of AD develop similar aneuploidy through amyloid-beta (Aß) inhibition of specific microtubule motors and consequent disruption of mitotic spindles. Here we tested the hypothesis that, like upregulated Aß, elevated LDL/cholesterol and altered intracellular cholesterol homeostasis also causes chromosomal instability. Specifically we found that: 1) high dietary cholesterol induces aneuploidy in mice, satisfying the hypothesis' first prediction, 2) Niemann-Pick C1 patients accumulate aneuploid fibroblasts, neurons, and glia, demonstrating a similar aneugenic effect of intracellular cholesterol accumulation in humans 3) oxidized LDL, LDL, and cholesterol, but not high-density lipoprotein (HDL), induce chromosome mis-segregation and aneuploidy in cultured cells, including neuronal precursors, indicating that LDL/cholesterol directly affects the cell cycle, 4) LDL-induced aneuploidy requires the LDL receptor, but not Aß, showing that LDL works differently than Aß, with the same end result, 5) cholesterol treatment disrupts the structure of the mitotic spindle, providing a cell biological mechanism for its aneugenic activity, and 6) ethanol or calcium chelation attenuates lipoprotein-induced chromosome mis-segregation, providing molecular insights into cholesterol's aneugenic mechanism, specifically through its rigidifying effect on the cell membrane, and potentially explaining why ethanol

  18. SMC5/6 is required for the formation of segregation-competent bivalent chromosomes during meiosis I in mouse oocytes.

    PubMed

    Hwang, Grace; Sun, Fengyun; O'Brien, Marilyn; Eppig, John J; Handel, Mary Ann; Jordan, Philip W

    2017-05-01

    SMC complexes include three major classes: cohesin, condensin and SMC5/6. However, the localization pattern and genetic requirements for the SMC5/6 complex during mammalian oogenesis have not previously been examined. In mouse oocytes, the SMC5/6 complex is enriched at the pericentromeric heterochromatin, and also localizes along chromosome arms during meiosis. The infertility phenotypes of females with a Zp3-Cre -driven conditional knockout (cKO) of Smc5 demonstrated that maternally expressed SMC5 protein is essential for early embryogenesis. Interestingly, protein levels of SMC5/6 complex components in oocytes decline as wild-type females age. When SMC5/6 complexes were completely absent in oocytes during meiotic resumption, homologous chromosomes failed to segregate accurately during meiosis I. Despite what appears to be an inability to resolve concatenation between chromosomes during meiosis, localization of topoisomerase IIα to bivalents was not affected; however, localization of condensin along the chromosome axes was perturbed. Taken together, these data demonstrate that the SMC5/6 complex is essential for the formation of segregation-competent bivalents during meiosis I, and findings suggest that age-dependent depletion of the SMC5/6 complex in oocytes could contribute to increased incidence of oocyte aneuploidy and spontaneous abortion in aging females. © 2017. Published by The Company of Biologists Ltd.

  19. SMC5/6 is required for the formation of segregation-competent bivalent chromosomes during meiosis I in mouse oocytes

    PubMed Central

    Hwang, Grace; Sun, Fengyun; Eppig, John J.; Handel, Mary Ann

    2017-01-01

    SMC complexes include three major classes: cohesin, condensin and SMC5/6. However, the localization pattern and genetic requirements for the SMC5/6 complex during mammalian oogenesis have not previously been examined. In mouse oocytes, the SMC5/6 complex is enriched at the pericentromeric heterochromatin, and also localizes along chromosome arms during meiosis. The infertility phenotypes of females with a Zp3-Cre-driven conditional knockout (cKO) of Smc5 demonstrated that maternally expressed SMC5 protein is essential for early embryogenesis. Interestingly, protein levels of SMC5/6 complex components in oocytes decline as wild-type females age. When SMC5/6 complexes were completely absent in oocytes during meiotic resumption, homologous chromosomes failed to segregate accurately during meiosis I. Despite what appears to be an inability to resolve concatenation between chromosomes during meiosis, localization of topoisomerase IIα to bivalents was not affected; however, localization of condensin along the chromosome axes was perturbed. Taken together, these data demonstrate that the SMC5/6 complex is essential for the formation of segregation-competent bivalents during meiosis I, and findings suggest that age-dependent depletion of the SMC5/6 complex in oocytes could contribute to increased incidence of oocyte aneuploidy and spontaneous abortion in aging females. PMID:28302748

  20. Automated identification of abnormal metaphase chromosome cells for the detection of chronic myeloid leukemia using microscopic images

    NASA Astrophysics Data System (ADS)

    Wang, Xingwei; Zheng, Bin; Li, Shibo; Mulvihill, John J.; Chen, Xiaodong; Liu, Hong

    2010-07-01

    Karyotyping is an important process to classify chromosomes into standard classes and the results are routinely used by the clinicians to diagnose cancers and genetic diseases. However, visual karyotyping using microscopic images is time-consuming and tedious, which reduces the diagnostic efficiency and accuracy. Although many efforts have been made to develop computerized schemes for automated karyotyping, no schemes can get be performed without substantial human intervention. Instead of developing a method to classify all chromosome classes, we develop an automatic scheme to detect abnormal metaphase cells by identifying a specific class of chromosomes (class 22) and prescreen for suspicious chronic myeloid leukemia (CML). The scheme includes three steps: (1) iteratively segment randomly distributed individual chromosomes, (2) process segmented chromosomes and compute image features to identify the candidates, and (3) apply an adaptive matching template to identify chromosomes of class 22. An image data set of 451 metaphase cells extracted from bone marrow specimens of 30 positive and 30 negative cases for CML is selected to test the scheme's performance. The overall case-based classification accuracy is 93.3% (100% sensitivity and 86.7% specificity). The results demonstrate the feasibility of applying an automated scheme to detect or prescreen the suspicious cancer cases.

  1. Moderate Ovarian Stimulation Does Not Increase the Incidence of Human Embryo Chromosomal Abnormalities in in Vitro Fertilization Cycles

    PubMed Central

    Bosch, Ernesto; Alamá, Pilar; Rubio, Carmen; Rodrigo, Lorena; Pellicer, Antonio

    2012-01-01

    Context: A high chromosomal abnormalities rate has been observed in human embryos derived from in vitro fertilization (IVF) treatments. The real incidence in natural cycles has been poorly studied, so whether this frequency may be induced by external factors, such as use of gonadotropins for ovarian stimulation, remains unknown. Design: We conducted a prospective cohort study in a University-affiliated private infertility clinic with a comparison between unstimulated and stimulated ovarian cycles in the same women. Preimplantation genetic screening by fluorescence in situ hybridization was performed in all viable d 3 embryos. Objective: The primary objective was to compare the incidence of embryo chromosomal abnormalities in an unstimulated cycle and in an ulterior moderate ovarian stimulated cycle. Secondary outcome measures were embryo quality, blastocyst rate of biopsied embryos, number of normal blastocysts per donor, type of chromosomal abnormalities, and clinical outcome. Results: One hundred eighty-five oocyte donors were initially recruited for the unstimulated cycle, and preimplantation genetic screening could be performed in 51 of them, showing 35.3% of embryo chromosomal abnormalities. Forty-six of them later completed a stimulated cycle. The sperm donor sample was the same for both cycles. The proportion of embryos displaying abnormalities in the unstimulated cycle was 34.8% (16 of 46), whereas it was 40.6% (123 of 303) in the stimulated cycle with risk difference = 5.8 [95% confidence interval (CI) = −20.6–9.0], and relative risk = 1.17 (95% CI = 0.77–1.77) (P = 0.45). When an intrasubject comparison was made, the abnormalities rate was 34.8% (95% CI = 20.5–49.1) in the unstimulated cycle and 38.2% (95% CI = 30.5–45.8) in the stimulated cycle [risk difference = 3.4 (95% CI = −17.9–11.2); P = 0.64]. No differences were observed for embryo quality and type of chromosomal abnormalities. Conclusions: Moderate ovarian stimulation in young

  2. Phosphorylation of Mycobacterium tuberculosis ParB Participates in Regulating the ParABS Chromosome Segregation System

    PubMed Central

    Baronian, Grégory; Ginda, Katarzyna; Berry, Laurence; Cohen-Gonsaud, Martin; Zakrzewska-Czerwińska, Jolanta; Jakimowicz, Dagmara; Molle, Virginie

    2015-01-01

    Here, we present for the first time that Mycobacterium tuberculosis ParB is phosphorylated by several mycobacterial Ser/Thr protein kinases in vitro. ParB and ParA are the key components of bacterial chromosome segregation apparatus. ParB is a cytosolic conserved protein that binds specifically to centromere-like DNA parS sequences and interacts with ParA, a weak ATPase required for its proper localization. Mass spectrometry identified the presence of ten phosphate groups, thus indicating that ParB is phosphorylated on eight threonines, Thr32, Thr41, Thr53, Thr110, Thr195, and Thr254, Thr300, Thr303 as well as on two serines, Ser5 and Ser239. The phosphorylation sites were further substituted either by alanine to prevent phosphorylation or aspartate to mimic constitutive phosphorylation. Electrophoretic mobility shift assays revealed a drastic inhibition of DNA-binding by ParB phosphomimetic mutant compared to wild type. In addition, bacterial two-hybrid experiments showed a loss of ParA-ParB interaction with the phosphomimetic mutant, indicating that phosphorylation is regulating the recruitment of the partitioning complex. Moreover, fluorescence microscopy experiments performed in the surrogate Mycobacterium smegmatis ΔparB strain revealed that in contrast to wild type Mtb ParB, which formed subpolar foci similar to M. smegmatis ParB, phoshomimetic Mtb ParB was delocalized. Thus, our findings highlight a novel regulatory role of the different isoforms of ParB representing a molecular switch in localization and functioning of partitioning protein in Mycobacterium tuberculosis. PMID:25807382

  3. Phosphorylation of Mycobacterium tuberculosis ParB participates in regulating the ParABS chromosome segregation system.

    PubMed

    Baronian, Grégory; Ginda, Katarzyna; Berry, Laurence; Cohen-Gonsaud, Martin; Zakrzewska-Czerwińska, Jolanta; Jakimowicz, Dagmara; Molle, Virginie

    2015-01-01

    Here, we present for the first time that Mycobacterium tuberculosis ParB is phosphorylated by several mycobacterial Ser/Thr protein kinases in vitro. ParB and ParA are the key components of bacterial chromosome segregation apparatus. ParB is a cytosolic conserved protein that binds specifically to centromere-like DNA parS sequences and interacts with ParA, a weak ATPase required for its proper localization. Mass spectrometry identified the presence of ten phosphate groups, thus indicating that ParB is phosphorylated on eight threonines, Thr32, Thr41, Thr53, Thr110, Thr195, and Thr254, Thr300, Thr303 as well as on two serines, Ser5 and Ser239. The phosphorylation sites were further substituted either by alanine to prevent phosphorylation or aspartate to mimic constitutive phosphorylation. Electrophoretic mobility shift assays revealed a drastic inhibition of DNA-binding by ParB phosphomimetic mutant compared to wild type. In addition, bacterial two-hybrid experiments showed a loss of ParA-ParB interaction with the phosphomimetic mutant, indicating that phosphorylation is regulating the recruitment of the partitioning complex. Moreover, fluorescence microscopy experiments performed in the surrogate Mycobacterium smegmatis ΔparB strain revealed that in contrast to wild type Mtb ParB, which formed subpolar foci similar to M. smegmatis ParB, phoshomimetic Mtb ParB was delocalized. Thus, our findings highlight a novel regulatory role of the different isoforms of ParB representing a molecular switch in localization and functioning of partitioning protein in Mycobacterium tuberculosis.

  4. Multipolar Spindle Pole Coalescence Is a Major Source of Kinetochore Mis-Attachment and Chromosome Mis-Segregation in Cancer Cells

    PubMed Central

    Silkworth, William T.; Nardi, Isaac K.; Scholl, Lindsey M.; Cimini, Daniela

    2009-01-01

    Many cancer cells display a CIN (Chromosome Instability) phenotype, by which they exhibit high rates of chromosome loss or gain at each cell cycle. Over the years, a number of different mechanisms, including mitotic spindle multipolarity, cytokinesis failure, and merotelic kinetochore orientation, have been proposed as causes of CIN. However, a comprehensive theory of how CIN is perpetuated is still lacking. We used CIN colorectal cancer cells as a model system to investigate the possible cellular mechanism(s) underlying CIN. We found that CIN cells frequently assembled multipolar spindles in early mitosis. However, multipolar anaphase cells were very rare, and live-cell experiments showed that almost all CIN cells divided in a bipolar fashion. Moreover, fixed-cell analysis showed high frequencies of merotelically attached lagging chromosomes in bipolar anaphase CIN cells, and higher frequencies of merotelic attachments in multipolar vs. bipolar prometaphases. Finally, we found that multipolar CIN prometaphases typically possessed γ-tubulin at all spindle poles, and that a significant fraction of bipolar metaphase/early anaphase CIN cells possessed more than one centrosome at a single spindle pole. Taken together, our data suggest a model by which merotelic kinetochore attachments can easily be established in multipolar prometaphases. Most of these multipolar prometaphase cells would then bi-polarize before anaphase onset, and the residual merotelic attachments would produce chromosome mis-segregation due to anaphase lagging chromosomes. We propose this spindle pole coalescence mechanism as a major contributor to chromosome instability in cancer cells. PMID:19668340

  5. Replacing the combined test by cell-free DNA testing in screening for trisomies 21, 18 and 13: impact on the diagnosis of other chromosomal abnormalities.

    PubMed

    Syngelaki, Argyro; Pergament, Eugene; Homfray, Tessa; Akolekar, Ranjit; Nicolaides, Kypros H

    2014-01-01

    To estimate the proportion of other chromosomal abnormalities that could be missed if combined testing was replaced by cell-free (cf) DNA testing as the method of screening for trisomies 21, 18 and 13. The prevalence of trisomies 21, 18 or 13, sex chromosome aneuploidies, triploidy and other chromosomal abnormalities was examined in pregnancies undergoing first-trimester combined screening and chorionic villus sampling (CVS). In 1,831 clinically significant chromosomal abnormalities in pregnancies with combined risk for trisomies 21, 18 and 13≥1:100, the contribution of trisomies 21, 18 or 13, sex chromosome aneuploidies, triploidy and other chromosomal abnormalities at high risk of adverse outcome was 82.9, 8.2, 3.9 and 5.0%, respectively. Combined screening followed by CVS for risk≥1:10 and cfDNA testing for risk 1:11-1:2,500 could detect 97% of trisomy 21 and 98% of trisomies 18 and 13. Additionally, 86% of monosomy X, half of 47,XXY, 47,XYY or 47,XXX, half of other chromosomal abnormalities and one third of triploidies, which are currently detected by combined screening and CVS for risk≥1:100, could be detected. Screening by cfDNA testing, contingent on results of combined testing, improves detection of trisomies, but misses a few of the other chromosomal abnormalities detected by screening with the combined test. © 2014 S. Karger AG, Basel.

  6. Variation in the levels of pregnancy-specific beta-1-glycoprotein in maternal serum from chromosomally abnormal pregnancies.

    PubMed

    Graham, G W; Crossley, J A; Aitken, D A; Connor, J M

    1992-06-01

    Human pregnancy-specific beta-1-glycoprotein (SP1) was assayed retrospectively in stored maternal serum (MS) samples from 82 chromosomally abnormal pregnancies and 377 matched controls. The median MSSP1 concentration in 48 Down's syndrome pregnancies was significantly elevated at 1.17 multiples of the control median (MOM), and significantly reduced (0.5 MOM) in a group of eight cases of unbalanced translocations. There was no significant difference in median SP1 concentrations in cases of trisomy 18, trisomy 13, balanced translocations, or sex chromosome abnormalities. A comparison with human chorionic gonadotrophin results in the same series of samples indicates that SP1 is a less sensitive predictor of Down's syndrome pregnancies.

  7. Müllerian Agenesis in Cat Eye Syndrome and 22q11 Chromosome Abnormalities: A Case Report and Literature Review.

    PubMed

    AlSubaihin, Abdulmajeed; VanderMeulen, John; Harris, Kate; Duck, John; McCready, Elizabeth

    2018-04-01

    Although Müllerian agenesis is the second most common cause of primary amenorrhea the underlying etiology in most cases is unknown. Müllerian agenesis has been reported as a rare finding associated with chromosomal aberrations of the 22q11 chromosomal region including at least 1 individual with cat eye syndrome (CES) and 10 individuals with deletions or duplications of the 22q11.2 region. However, a potential link between 22q11 abnormalities and uterine malformations has been difficult to adequately ascertain because of the limited case reports in the literature. We report a second case of Müllerian agenesis in a girl with CES. A 16-year-old girl presented with bilateral colobomata, primary amenorrhea, and absence of the uterus and upper vagina on pelvic magnetic resonance imaging. Microarray analysis showed tetrasomy of the pericentromeric region of chromosome 22 diagnostic of CES. Müllerian aplasia/hypoplasia might represent a rare feature in CES and should be considered in the investigation of young girls with this syndrome. An increasing number of cases with 22q11 chromosome abnormalities and Müllerian agenesis further highlights the possibility of a gene within the 22q11 region that might mediate normal Müllerian development in girls. Copyright © 2017 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc. All rights reserved.

  8. [Combined G-banded karyotyping and multiplex ligation-dependent probe amplification for the detection of chromosomal abnormalities in fetuses with congenital heart defects].

    PubMed

    Liu, Yang; Xie, Jiansheng; Geng, Qian; Xu, Zhiyong; Wu, Weiqin; Luo, Fuwei; Li, Suli; Wang, Qin; Chen, Wubin; Tan, Hongxi; Zhang, Hu

    2017-02-10

    To assess the value of G-banded karyotyping in combination with multiplex ligation-dependent probe amplification (MLPA) as a tool for the detection of chromosomal abnormalities in fetuses with congenital heart defects. The combined method was used to analyze 104 fetuses with heart malformations identified by ultrasonography. Abnormal findings were confirmed with chromosomal microarray analysis (CMA). Nineteen (18%) fetuses were found to harbor chromosomal aberrations by G-banded karyotyping and MLPA. For 93 cases, CMA has detected abnormalities in 14 cases including 10 pathogenic copy number variations (CNVs) and 4 CNVs of uncertain significance (VOUS). MLPA was able to detect all of the pathogenic CNVs and 1 VOUS CNV. Combined use of G-banded karyotyping and MLPA is a rapid, low-cost and effective method to detect chromosomal abnormalities in fetuses with various heart malformations.

  9. Chromosomal abnormalities in infertile men with azoospermia and severe oligozoospermia in Qatar and their association with sperm retrieval intracytoplasmic sperm injection outcomes.

    PubMed

    Arafa, Mohamed M; Majzoub, Ahmad; AlSaid, Sami S; ElAnsari, Walid; Al Ansari, Abdulla; Elbardisi, Yara; Elbardisi, Haitham T

    2018-03-01

    To study the types and incidence of chromosomal abnormalities in infertile men with azoospermia and severe oligozoospermia in Qatar, and to compare the hormonal changes, testicular sperm retrieval rate, and intracytoplasmic sperm injection (ICSI) outcome between patients with chromosomal abnormalities and patients with idiopathic infertility. This study involved the retrospective chart review of 625 infertile male patients attending an academic tertiary medical centre in Qatar. Retrieved information included data on medical history, family history, clinical examination, semen analysis, initial hormonal profiles, and genetic studies, ICSI, and sperm retrieval results. The incidence of chromosomal abnormalities was 9.59% (10.6% amongst Qatari patients, 9.04% amongst non-Qataris). About 63.6% of the sample had azoospermia, of whom 10.8% had chromosomal abnormalities. Roughly 36.4% of the sample had oligozoospermia, of whom 7.5% had chromosomal abnormalities. There were no differences between patients with chromosomal abnormalities and those with idiopathic infertility for demographic and infertility features; but for the hormonal profiles, patients with idiopathic infertility had significantly lower luteinising hormone and follicle-stimulating hormone values. For ICSI outcomes, patients with chromosomal abnormalities had a significantly lower total sperm retrieval rate (47.4% vs 65.8%), surgical sperm retrieval rate (41.2% vs 58.1%), and lower clinical pregnancy rate (16.7% vs 26.6%) when compared to the idiopathic infertility group. The incidence of chromosomal abnormalities in Qatar as a cause of severe male infertility is within a similar range as their prevalence internationally.

  10. Human Artificial Chromosomes with Alpha Satellite-Based De Novo Centromeres Show Increased Frequency of Nondisjunction and Anaphase Lag

    PubMed Central

    Rudd, M. Katharine; Mays, Robert W.; Schwartz, Stuart; Willard, Huntington F.

    2003-01-01

    Human artificial chromosomes have been used to model requirements for human chromosome segregation and to explore the nature of sequences competent for centromere function. Normal human centromeres require specialized chromatin that consists of alpha satellite DNA complexed with epigenetically modified histones and centromere-specific proteins. While several types of alpha satellite DNA have been used to assemble de novo centromeres in artificial chromosome assays, the extent to which they fully recapitulate normal centromere function has not been explored. Here, we have used two kinds of alpha satellite DNA, DXZ1 (from the X chromosome) and D17Z1 (from chromosome 17), to generate human artificial chromosomes. Although artificial chromosomes are mitotically stable over many months in culture, when we examined their segregation in individual cell divisions using an anaphase assay, artificial chromosomes exhibited more segregation errors than natural human chromosomes (P < 0.001). Naturally occurring, but abnormal small ring chromosomes derived from chromosome 17 and the X chromosome also missegregate more than normal chromosomes, implicating overall chromosome size and/or structure in the fidelity of chromosome segregation. As different artificial chromosomes missegregate over a fivefold range, the data suggest that variable centromeric DNA content and/or epigenetic assembly can influence the mitotic behavior of artificial chromosomes. PMID:14560014

  11. Human artificial chromosomes with alpha satellite-based de novo centromeres show increased frequency of nondisjunction and anaphase lag.

    PubMed

    Rudd, M Katharine; Mays, Robert W; Schwartz, Stuart; Willard, Huntington F

    2003-11-01

    Human artificial chromosomes have been used to model requirements for human chromosome segregation and to explore the nature of sequences competent for centromere function. Normal human centromeres require specialized chromatin that consists of alpha satellite DNA complexed with epigenetically modified histones and centromere-specific proteins. While several types of alpha satellite DNA have been used to assemble de novo centromeres in artificial chromosome assays, the extent to which they fully recapitulate normal centromere function has not been explored. Here, we have used two kinds of alpha satellite DNA, DXZ1 (from the X chromosome) and D17Z1 (from chromosome 17), to generate human artificial chromosomes. Although artificial chromosomes are mitotically stable over many months in culture, when we examined their segregation in individual cell divisions using an anaphase assay, artificial chromosomes exhibited more segregation errors than natural human chromosomes (P < 0.001). Naturally occurring, but abnormal small ring chromosomes derived from chromosome 17 and the X chromosome also missegregate more than normal chromosomes, implicating overall chromosome size and/or structure in the fidelity of chromosome segregation. As different artificial chromosomes missegregate over a fivefold range, the data suggest that variable centromeric DNA content and/or epigenetic assembly can influence the mitotic behavior of artificial chromosomes.

  12. Epigenetic abnormalities associated with a chromosome 18(q21-q22) inversion and a Gilles de la Tourette syndrome phenotype

    PubMed Central

    State, Matthew W.; Greally, John M.; Cuker, Adam; Bowers, Peter N.; Henegariu, Octavian; Morgan, Thomas M.; Gunel, Murat; DiLuna, Michael; King, Robert A.; Nelson, Carol; Donovan, Abigail; Anderson, George M.; Leckman, James F.; Hawkins, Trevor; Pauls, David L.; Lifton, Richard P.; Ward, David C.

    2003-01-01

    Gilles de la Tourette syndrome (GTS) is a potentially debilitating neuropsychiatric disorder defined by the presence of both vocal and motor tics. Despite evidence that this and a related phenotypic spectrum, including chronic tics (CT) and Obsessive Compulsive Disorder (OCD), are genetically mediated, no gene involved in disease etiology has been identified. Chromosomal abnormalities have long been proposed to play a causative role in isolated cases of GTS spectrum phenomena, but confirmation of this hypothesis has yet to be forthcoming. We describe an i(18q21.1-q22.2) inversion in a patient with CT and OCD. We have fine mapped the telomeric aspect of the rearrangement to within 1 Mb of a previously reported 18q22 breakpoint that cosegregated in a family with GTS and related phenotypes. A comprehensive characterization of this genomic interval led to the identification of two transcripts, neither of which was found to be structurally disrupted. Analysis of the epigenetic characteristics of the region demonstrated a significant increase in replication asynchrony in the patient compared to controls, with the inverted chromosome showing delayed replication timing across at least a 500-kb interval. These findings are consistent with long-range functional dysregulation of one or more genes in the region. Our data support a link between chromosomal aberrations and epigenetic mechanisms in GTS and suggest that the study of the functional consequences of balanced chromosomal rearrangements is warranted in patients with phenotypes of interest, irrespective of the findings regarding structurally disrupted transcripts. PMID:12682296

  13. Contact zone between chromosomal races of Mus musculus domesticus. 2. Fertility and segregation in laboratory-reared and wild mice heterozygous for multiple robertsonian rearrangements.

    PubMed

    Castiglia, R; Capanna, E

    2000-08-01

    Litter size, anaphase I nondisjunction and X-Y dissociation at metaphase I were studied in homozygous and heterozygous house mice from a central Italian chromosomal hybrid zone between the CD (2n=22) race and the standard race (2n=40). We also observed the segregation of the two chromosomal forms (Robertsonian and non-Robertsonian) in male and female multiple heterozygotes from the karyotype of their offspring and chromosomal arm counts of metaphase II. Litter size was significantly reduced in the F1 hybrids, but there was no difference in litter size between male and female F1s. Fertility in wild mice decreased with increasing numbers of structural heterozygosities (0-5). Some metacentrics appear to be under meiotic drive but there was no rule as to which of the two forms was favoured in backcrosses. An original observation of a negative correlation between the length of metacentrics and transmission rate was described in hybrids. Slight cosegregation of chromosomes with a similar morphology was present in the progeny of males and females. These observations are discussed in relation to the stability of this hybrid zone through time.

  14. Fluorescence in situ hybridization of TP53 for the detection of chromosome 17 abnormalities in myelodysplastic syndromes.

    PubMed

    Sánchez-Castro, Judit; Marco-Betés, Víctor; Gómez-Arbonés, Xavier; García-Cerecedo, Tomás; López, Ricard; Talavera, Elisabeth; Fernández-Ruiz, Sara; Ademà, Vera; Marugan, Isabel; Luño, Elisa; Sanzo, Carmen; Vallespí, Teresa; Arenillas, Leonor; Marco Buades, Josefa; Batlle, Ana; Buño, Ismael; Martín Ramos, María Luisa; Blázquez Rios, Beatriz; Collado Nieto, Rosa; Vargas, Ma Teresa; González Martínez, Teresa; Sanz, Guillermo; Solé, Francesc

    2015-01-01

    Conventional G-banding cytogenetics (CC) detects chromosome 17 (chr17) abnormalities in 2% of patients with de novo myelodysplastic syndromes (MDS). We used CC and fluorescence in situ hybridization (FISH) (LSI p53/17p13.1) to assess deletion of 17p in 531 patients with de novo MDS from the Spanish Group of Hematological Cytogenetics. FISH detected - 17 or 17p abnormalities in 13 cases (2.6%) in whom no 17p abnormalities were revealed by CC: 0.9% of patients with a normal karyotype, 0% in non-informative cytogenetics, 50% of patients with a chr17 abnormality without loss of 17p and 4.7% of cases with an abnormal karyotype not involving chr17. Our results suggest that applying FISH of 17p13 to identify the number of copies of the TP53 gene could be beneficial in patients with a complex karyotype. We recommend using FISH of 17p13 in young patients with a normal karyotype or non-informative cytogenetics, and always in isolated del(17p).

  15. Nonstructural NSs protein of rift valley fever virus interacts with pericentromeric DNA sequences of the host cell, inducing chromosome cohesion and segregation defects.

    PubMed

    Mansuroglu, Z; Josse, T; Gilleron, J; Billecocq, A; Leger, P; Bouloy, M; Bonnefoy, E

    2010-01-01

    Rift Valley fever virus (RVFV) is an emerging, highly pathogenic virus; RVFV infection can lead to encephalitis, retinitis, or fatal hepatitis associated with hemorrhagic fever in humans, as well as death, abortions, and fetal deformities in animals. RVFV nonstructural NSs protein, a major factor of the virulence, forms filamentous structures in the nuclei of infected cells. In order to further understand RVFV pathology, we investigated, by chromatin immunoprecipitation, immunofluorescence, fluorescence in situ hybridization, and confocal microscopy, the capacity of NSs to interact with the host genome. Our results demonstrate that even though cellular DNA is predominantly excluded from NSs filaments, NSs interacts with some specific DNA regions of the host genome such as clusters of pericentromeric gamma-satellite sequence. Targeting of these sequences by NSs was correlated with the induction of chromosome cohesion and segregation defects in RVFV-infected murine, as well as sheep cells. Using recombinant nonpathogenic virus rZHDeltaNSs210-230, expressing a NSs protein deleted of its region of interaction with cellular factor SAP30, we showed that the NSs-SAP30 interaction was essential for NSs to target pericentromeric sequences, as well as for induction of chromosome segregation defects. The effect of RVFV upon the inheritance of genetic information is discussed with respect to the pathology associated with fetal deformities and abortions, highlighting the main role played by cellular cofactor SAP30 on the establishment of NSs interactions with host DNA sequences and RVFV pathogenesis.

  16. Quantitative analysis of chromosomal CGH in human breast tumors associates copy number abnormalities with p53 status and patient survival

    PubMed Central

    Jain, Ajay N.; Chin, Koei; Børresen-Dale, Anne-Lise; Erikstein, Bjorn K.; Lonning, Per Eystein; Kaaresen, Rolf; Gray, Joe W.

    2001-01-01

    We present a general method for rigorously identifying correlations between variations in large-scale molecular profiles and outcomes and apply it to chromosomal comparative genomic hybridization data from a set of 52 breast tumors. We identify two loci where copy number abnormalities are correlated with poor survival outcome (gain at 8q24 and loss at 9q13). We also identify a relationship between abnormalities at two loci and the mutational status of p53. Gain at 8q24 and loss at 5q15-5q21 are linked with mutant p53. The 9q and 5q losses suggest the possibility of gene products involved in breast cancer progression. The analytical techniques are general and also are applicable to the analysis of array-based expression data. PMID:11438741

  17. Analysis of chromosomal abnormalities by CGH-array in patients with dysmorphic and intellectual disability with normal karyotype

    PubMed Central

    Pratte-Santos, Rodrigo; Ribeiro, Katyanne Heringer; Santos, Thainá Altoe; Cintra, Terezinha Sarquis

    2016-01-01

    ABSTRACT Objective To investigate chromosomal abnormalities by CGH-array in patients with dysmorphic features and intellectual disability with normal conventional karyotype. Methods Retrospective study, carried out from January 2012 to February 2014, analyzing the CGH-array results of 39 patients. Results Twenty-six (66.7%) patients had normal results and 13 (33.3%) showed abnormal results - in that, 6 (15.4%) had pathogenic variants, 6 (15.4%) variants designated as uncertain and 1 (2.5%) non-pathogenic variants. Conclusion The characterization of the genetic profile by CGH-array in patients with intellectual disability and dysmorphic features enabled making etiologic diagnosis, followed by genetic counseling for families and specific treatment. PMID:27074231

  18. Chronic lymphocytic leukemia-associated chromosomal abnormalities and miRNA deregulation.

    PubMed

    Kiefer, Yvonne; Schulte, Christoph; Tiemann, Markus; Bullerdiek, Joern

    2012-01-01

    Chronic lymphocytic leukemia is the most common leukemia in adults. By cytogenetic investigations major subgroups of the disease can be identified that reflect different routes of tumor development. Of these chromosomal deviations, trisomy 12 and deletions of parts of either the long arm of chromosome 13, the long arm of chromosome 11, or the short arm of chromosome 17 are most commonly detected. In some of these aberrations the molecular target has been identified as eg, ataxia telangiectasia mutated (ATM) in case of deletions of chromosomal region 11q22~23 and the genes encoding microRNAs miR-15a/16-1 as likely targets of deletions of chromosomal band 13q14.3. Of note, these aberrations do not characterize independent subgroups but often coexist within the metaphases of one tumor. Generally, complex aberrations are associated with a worse prognosis than simple karyotypic alterations. Due to smaller sizes of the missing segment the detection of recurrent deletions is not always possible by means of classical cytogenetics but requires more advanced techniques as in particular fluorescence in situ hybridization (FISH). Nevertheless, at this time it is not recommended to replace classical cytogenetics by FISH because this would miss additional information given by complex or secondary karyotypic alterations. However, the results of cytogenetic analyses allow the stratification of prognostic and predictive groups of the disease. Of these, the group characterized by deletions involving TP53 is clinically most relevant. In the future refined methods as eg, array-based comparative genomic hybridization will supplement the existing techniques to characterize CLL.

  19. Successful treatment of an infant with constitutional chromosomal abnormality and hemangiopericytoma with chemotherapy alone.

    PubMed

    Gowans, L Kate; Bentz, Michael L; DeSantes, Kenneth B; Thompson, Kate J

    2007-06-01

    Hemangiopericytoma is a rare vascular tumor, of which 5% to 10% occur in the pediatric population. Although usually benign in infants, local recurrence, metastasis, and deaths have been reported. Clonal chromosomal rearrangements have been described, most involving the long arm of chromosome 12. We report a case of a 6-month-old boy with an hemangiopericytoma of the left forearm initially incorrectly diagnosed as hemangioma. He was treated successfully with chemotherapy alone using vincristine, doxorubicin, actinomycin-D, and cyclophosphamide. Although cytogenetic analysis was not performed on his biopsy, it was later discovered that a prenatal karyotype had shown 46,XY,inv(12)(q15q24.1).

  20. Prenatal diagnosis of chromosomal abnormalities using array-based comparative genomic hybridization

    USDA-ARS?s Scientific Manuscript database

    This study was designed to evaluate the feasibility of using a targeted array-CGH strategy for prenatal diagnosis of genomic imbalances in a clinical setting of current pregnancies. Women undergoing prenatal diagnosis were counseled and offered array-CGH (BCM V4.0) in addition to routine chromosome ...

  1. v-Src-driven transformation is due to chromosome abnormalities but not Src-mediated growth signaling.

    PubMed

    Honda, Takuya; Morii, Mariko; Nakayama, Yuji; Suzuki, Ko; Yamaguchi, Noritaka; Yamaguchi, Naoto

    2018-01-18

    v-Src is the first identified oncogene product and has a strong tyrosine kinase activity. Much of the literature indicates that v-Src expression induces anchorage-independent and infinite cell proliferation through continuous stimulation of growth signaling by v-Src activity. Although all of v-Src-expressing cells are supposed to form transformed colonies, low frequencies of v-Src-induced colony formation have been observed so far. Using cells that exhibit high expression efficiencies of inducible v-Src, we show that v-Src expression causes cell-cycle arrest through p21 up-regulation despite ERK activation. v-Src expression also induces chromosome abnormalities and unexpected suppression of v-Src expression, leading to p21 down-regulation and ERK inactivation. Importantly, among v-Src-suppressed cells, only a limited number of cells gain the ability to re-proliferate and form transformed colonies. Our findings provide the first evidence that v-Src-driven transformation is attributed to chromosome abnormalities, but not continuous stimulation of growth signaling, possibly through stochastic genetic alterations.

  2. Effects of age on segregation of the X and Y chromosomes in cultured lymphocytes from Chinese men.

    PubMed

    Song, Yaxian; Chen, Qian; Zhang, Zhen; Hou, Heli; Zhang, Ding; Shi, Qinghua

    2009-08-01

    Chromosome malsegregation in binucleated lymphocytes is a useful endpoint to evaluate age effect on genetic stability. However, the investigations on chromosome malsegregation in binucleated lymphocytes from Chinese are scarce. In this study, peripheral blood lymphocytes were collected from 14 old (60-70 years) and 10 young (22-26 years) healthy Chinese men. To detect malsegregation of the sex chromosomes, multi-color fluorescence in situ hybridization (FISH) was performed on binucleated lymphocytes, cytokinesis-blocked by cytochalasin B at the first mitosis after phytohaemagglutinin stimulation. Compared with that in young men, a significant increase in frequencies of loss of chromosome X (9.2 +/- 3.2 per thousand vs. 1.1 +/- 0.9 per thousand, P < 0.001) and Y (2.5 +/- 1.9 per thousand vs. 0.2 +/- 0.3 per thousand, P < 0.001) was found in old men. Similarly, nondisjunction of chromosome X (16.5 +/- 3.4 per thousand vs. 3.5 +/- 1.1 per thousand, P < 0.001) and Y (7.2 +/- 2.6 per thousand vs. 2.4 +/- 1.3 per thousand, P < 0.001) occurred more frequently in old men than in young men. Regardless of donor's age, nondisjunction is more prevalent than loss for both chromosome X and Y. The frequencies of observed simultaneous malsegregation were relatively higher than the expected, suggesting an association between malsegregation. These results indicated that in Chinese men, malsegregation of the sex chromosomes increases with age in an associated fashion, and nondisjunction accounts for the majority of spontaneous chromosome malsegregation.

  3. [Structural and functional organization of centromeres in plant chromosomes].

    PubMed

    Silkova, O G; Loginova, D B

    2014-12-01

    The centromere is a specific chromosomal locus that forms the protein complex and kinetochore, maintains sister chromatid cohesion, controls chromosome attachment to the spindle, and coordinates chromosome movement during mitosis and meiosis. Defective centromere assembly or its dysfunction causes cell cycle arrest, structural abnormalities of the chromosomes, and aneuploidy. This review collects the data on the structure, functions, and epigenetic modification of centromeric chromatin, the structure and functions of the kinetochore, and sister chromatid cohesion. Taken together, these data provide insight into the specific architecture and functioning of the centromere during chromosome division and segregation in plants.

  4. High Mitotic Activity of Polo-like Kinase 1 Is Required for Chromosome Segregation and Genomic Integrity in Human Epithelial Cells*

    PubMed Central

    Lera, Robert F.; Burkard, Mark E.

    2012-01-01

    Protein kinases play key roles in regulating human cell biology, but manifold substrates and functions make it difficult to understand mechanism. We tested whether we could dissect functions of a pleiotropic mitotic kinase, Polo-like kinase 1 (Plk1), via distinct thresholds of kinase activity. We accomplished this by titrating Plk1 activity in RPE1 human epithelial cells using chemical genetics and verifying results in additional lines. We found that distinct activity thresholds are required for known functions of Plk1 including (from low to high activity) bipolar spindle formation, timely mitotic entry, and formation of a cytokinesis cleavage furrow. Subtle losses in Plk1 activity impaired chromosome congression and produced severe anaphase dysfunction characterized by poor separation of chromosome masses. These two phenotypes were separable, suggesting that they stem from distinct phosphorylation events. Impaired chromosome segregation in anaphase was the most sensitive to modest loss in Plk1 activity. Mechanistically, it was associated with unpaired sister chromatids with stretched kinetochores, suggestive of merotelic attachments. The C-terminal Polo box domain of Plk1 was required for its anaphase function, although it was dispensable for forming a bipolar spindle. The ultimate effect of partial inhibition of Plk1 was the formation of micronuclei, an increase in tetraploid progeny, and senescence. These results demonstrate that different thresholds of Plk1 activity can elicit distinct phenotypes, illustrating a general method for separating pleiotropic functions of a protein kinase even when these are executed close in time. PMID:23105120

  5. [Fetal malformations and chromosome abnormalities diagnosed at the Center of Prenatal Diagnosis of the University of Aquila in the 1995-1998 triennium].

    PubMed

    Carta, G; Iovenitti, P; D'Alfonso, A; Mascaretti, G; Moscarini, M

    1999-10-01

    Over the past few years numerous techniques have been developed, allowing an evaluation of fetal physiopathology that was unthinkable until recently. The authors describe 20 cases of fetal malformations and chromosomal abnormalities diagnosed by scan and amniocentesis at the Centre for Diagnosis and Obstetric Prophylaxis at L'Aquila University. Between January 1995 and April 1998 a total of 1180 amniocentesis and 4000 obstetric scans were performed in a group of 1650 pregnant women. Of the patients examined using ultrasound scan, 8 presented manifest fetal pathologies, of which 5 were associated with chromosome abnormalities: 1) left ventricular hypoplasia, common atrium, tricuspid dysplasia; 2) omphalocele; 3) Morgagni-Stewart-Morel syndrome; 4) plurilobate cystic hygroma; 5) duodenal atresia; 6) Dandy-Walker syndrome; 7) cystic hygroma and hydrops; 8) cystic hygroma, hydrops, cardiopathy and Dandy-Walker syndrome. Among the pregnant women undergoing amniocentesis without a prior diagnosis of fetal malformation, 12 presented pathological fetal karyotypes: 2 cases of Turner's syndrome; 2 cases of Edward's syndrome; 2 cases of Klinefelter's syndrome, of deletion of a stretch of chromosome 8; 1 case of Down's syndrome; 2 cases of supernumerary marker chromosome; 1 twin pregnancy with Klinefelter's syndrome in one twin and paracentric inversion of chromosome 13 in the other; 1 twin pregnancy with a small supernumerary marker chromosome in both twins. Ultrasonography often enables the diagnosis of congenital abnormalities not associated with chromosome pathologies. However, karyotype studies play an essential role in pregnancies with a high genetic risk.

  6. Anti-proliferative effects, cell cycle G2/M phase arrest and blocking of chromosome segregation by probimane and MST-16 in human tumor cell lines

    PubMed Central

    Lu, Da Yong; Huang, Min; Xu, Cheng Hui; Yang, Wei Yi; Hu, Chao Xin; Lin, Li Ping; Tong, Lin Jiang; Li, Mei Hong; Lu, Wei; Zhang, Xiong Wen; Ding, Jian

    2005-01-01

    Background Anticancer bisdioxopiperazines, including ICRF-154, razoxane (Raz, ICRF-159) and ICRF-193, are a family of anticancer agents developed in the UK, especially targeting metastases of neoplasms. Two other bisdioxopiperazine derivatives, probimane (Pro) and MST-16, were synthesized at the Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China. Cytotoxic activities and mechanisms of Raz (+)-steroisomer (ICRF-187, dexrazoxane), Pro and MST-16 against tumor cells were evaluated by MTT colorimetry, flow cytometry and karyotyping. Results Pro was cytotoxic to human tumor cell lines in vitro (IC50<50 μM for 48 h). Four human tumor cell lines (SCG-7901, K562, A549 and HL60) were susceptible to Pro at low inhibitory concentrations (IC50 values < 10 μM for 48 h). Although the IC50 against HeLa cell line of vincristine (VCR, 4.56 μM), doxorubicin (Dox, 1.12 μM) and 5-fluoruouracil (5-Fu, 0.232 μM) are lower than Pro (5.12 μM), ICRF-187 (129 μM) and MST-16 (26.4 μM), VCR, Dox and 5-Fu shows a low dose-related – high cytotoxic activity. Time-response studies showed that the cytotoxic effects of Pro are increased for 3 days in human tumor cells, whereas VCR, Dox and 5-Fu showed decreased cytotoxic action after 24 h. Cell cycle G2/M phase arrest and chromosome segregation blocking by Pro and MST-16 were noted. Although there was similar effects of Pro and MST-16 on chromosome segregation blocking action and cell cycle G2/M phase arrest at 1- 4 μM, cytotoxicity of Pro against tumor cells was higher than that of MST-16 in vitro by a factor of 3- 10 folds. Our data show that Pro may be more effective against lung cancer and leukemia while ICRF-187 and MST-16 shows similar IC50 values only against leukemia. Conclusion It suggests that Pro has a wider spectrum of cytotoxic effects against human tumor cells than other bisdioxopiperazines, especially against solid tumors, and with a single cytotoxic pathway of Pro and MST-16 affecting

  7. Arsenic Exposure, Dermatological Lesions, Hypertension, and Chromosomal Abnormalities among People in a Rural Community of Northwest Iran

    PubMed Central

    Dastgiri, Saeed; Fizi, Mohammad A.H.; Olfati, Nahid; Zolali, Shahin; Pouladi, Nasser; Azarfam, Parvin

    2010-01-01

    Chronic exposure to arsenic compounds is one of the major public-health problems in many developing and some developed countries. The aim of this study was to investigate the effects of chronic exposure to arsenic on dermatological lesions, hypertension, and chromosomal abnormalities among people in a community in the northwest of Iran. The occurrence of dermatological lesions, hypertension, and chromosomal abnormalities was investigated in two groups: Ghopuz village, including 101 subjects with chronic exposure to arsenic in drinking-water and Mayan village, including 107 subjects with no exposure. Daily/yearly absorbed amounts of arsenic were calculated for all subjects. Cumulative arsenic index for each individual was then estimated on the basis of age, water consumption, and location of residence. Arsenic concentration in drinking-water sources in Ghopuz and Mayan villages was 1031±1103 μg/L and non-detectable respectively. The mean systolic blood pressure in the exposure group [n=137, 95% confidence interval (CI 132–142)] was significantly higher than that in the control group (n=107, 95% CI 99.9–114). A similar significant difference was observed for diastolic blood pressure (exposed: n=82, 95% CI 79–85 vs non-exposed: n=71, 95% CI 66–75). The incidence of hyperkeratosis was 34 times higher among the exposure group compared to the control subjects [odds ratio (OR)=34, p<0.001)]. A significant difference was also observed in the occurrence of skin-pigmentation between the two groups (OR=2.4, p<0.007). Location and severity of the pigmentations were statistically different between the two groups. Twenty-five percent of the subjects in the exposure group showed chromosomal abnormalities (p=0.05). Arsenic exposure was a serious health problem in the region. More studies are needed to investigate the long-term effects and dose-response relationship of arsenic in the region and similar areas. Wide-ranging monitoring programmes for drinking-water sources

  8. Eosinophilic fasciitis associated with hypereosinophilia, abnormal bone-marrow karyotype and inversion of chromosome 5.

    PubMed

    Ferguson, J S; Bosworth, J; Min, T; Mercieca, J; Holden, C A

    2014-03-01

    We report the case of a male patient presenting with eosinophilia, pulmonary oedema and eosinophilic fasciitis (EF). He had the classic clinical appearance and magnetic resonance imaging of EF. Cytogenetic analysis of the bone marrow revealed a previously undescribed pericentric inversion of chromosome 5. Overall, the presentation was consistent with a diagnosis of chronic eosinophilic leukaemia, not otherwise specified (CEL-NOS). Dermatologists should consult a haematologist in cases of EF, in order to rule out possible haematological malignancies. © 2013 British Association of Dermatologists.

  9. The use of molecular and cytogenetic methods as a valuable tool in the detection of chromosomal abnormalities in horses: a case of sex chromosome chimerism in a Spanish purebred colt.

    PubMed

    Demyda-Peyrás, S; Membrillo, A; Bugno-Poniewierska, M; Pawlina, K; Anaya, G; Moreno-Millán, M

    2013-01-01

    Chromosomal abnormalities associated to sex chromosomes are reported as a problem more common than believed to be in horses. Most of them remain undiagnosed due to the complexity of the horse karyotype and the lack of interest of breeders and veterinarians in this type of diagnosis. Approximately 10 years ago, the Spanish Purebred Breeders Association implemented a DNA paternity test to evaluate the pedigree of every newborn foal. All candidates who showed abnormal or uncertain results are routinely submitted to cytogenetical analysis to evaluate the presence of chromosomal abnormalities. We studied the case of a foal showing 3 and even 4 different alleles in several loci in the short tandem repeat (STR) -based DNA parentage test. To confirm these results, a filiation test was repeated using follicular hair DNA showing normal results. A complete set of conventional and molecular cytogenetic analysis was performed to determine their chromosomal complements. C-banding and FISH had shown that the foal presents a sex chimerism 64,XX/64,XY with a cellular percentage of approximately 70/30, diagnosed in blood samples. The use of a diagnostic approach combining routine parentage QF-PCR-based STR screening tested with classical or molecular cytogenetic analysis could be a powerful tool that allows early detection of foals that will have a poor or even no reproductive performance due to chromosomal abnormalities, saving time, efforts and breeders' resources. Copyright © 2013 S. Karger AG, Basel.

  10. Spermatozoa with numerical chromosomal abnormalities are more prone to be retained by Annexin V-MACS columns.

    PubMed

    Esbert, M; Godo, A; Soares, S R; Florensa, M; Amorós, D; Ballesteros, A; Vidal, F

    2017-07-01

    Colloidal super-paramagnetic microbeads conjugated with annexin V are effective for separating apoptotic spermatozoa by MACS as a result of the high affinity of annexin V for externalized PS molecules. The effectiveness of the procedure in reducing the percentage of sperm with fragmented DNA and abnormal morphology has also been reported. However, it is still unknown if it could decrease the percentage of aneuploid spermatozoa. The objective of our prospective study, performed on 16 males with abnormal FISH on spermatozoa, was to assess if MACS columns were useful tools to retain spermatozoa carrying chromosomal abnormalities in semen samples processed after density gradient centrifugation (DGC). The pellet obtained after DGC was subjected to MACS, and sperm FISH analyses were performed both in the eluded fraction and in the fraction retained in the column. The observed frequencies of disomy and nullisomy 13, 18, and 21, X and Y, as well as the diploidy rates in the MACS eluded fraction and the fraction retained in the MACS column were recorded. We observed that the frequencies of aneuploidies in the eluded fraction were lower than in the fraction retained in the MACS column (0.59% vs. 0.75%; p = 0.010). DGC determined a significant reduction in sperm concentration (z-ratio = 2.83; p = 0.005) and a significant increase in sperm progressive motility (z-ratio = -3.5; p < 0.001). MACS also led to a significant reduction in sperm concentration (z-ratio = 3.14; p = 0.002) and a significant increase in progressive motility (z-ratio = -2.59; p = 0.01) when compared with the post-DGC sample. Sperm concentration was similar in the two fractions generated by MACS (z-ratio = 0.63; p = 0.52), while progressive motility was significantly higher in the MACS eluded fraction (z-ratio = 2.42; p = 0.02). According to our results, MACS columns are able to selectively retain spermatozoa carrying chromosomal abnormalities. Furthermore, the performance of DGC

  11. Total alpha-fetoprotein and Lens culinaris agglutinin-reactive alpha-fetoprotein in fetal chromosomal abnormalities.

    PubMed

    Yamamoto, R; Azuma, M; Kishida, T; Yamada, H; Satomura, S; Fujimoto, S

    2001-11-01

    To examine the differences in multiples of the median (MoM) of total alpha-fetoprotein, and the proportion of Lens culinaris agglutinin reactive alpha-fetoprotein (% alpha-fetoprotein-L2 + L3) in the maternal serum and amniotic fluid of pregnant women whose fetuses were diagnosed with autosomal or sex chromosomal abnormalities. Prospective consecutive series. University hospital. Maternal sera and amniotic fluids from 46 pregnant women with trisomy 21 fetuses, 10 pregnant women with trisomy 18 fetuses, one pregnant woman with a trisomy 13 fetus, six pregnant women with fetal sex chromosomal abnormalities, and 100 pregnant women for whom the fetal karyotype was diagnosed as normal following a genetic amniocentesis. The proportion of alpha-fetoprotein-L2 + L3 in maternal serum for trisomy 21 (40.3%. P < 0.0001) and trisomy 18 (39.8%, P < 0.05) showed a significantly higher value compared with normal (32.6%). The proportion of alpha-fetoprotein-L2 + L3 in amniotic fluid was significantly higher (P < 0.0001) for trisomy 21 (46.6%) than for a normal karyotype (41.5%). Only for the trisomy 21 group was there a strong correlation in the % alpha-fetoprotein-L2 + L3 between maternal serum and amniotic fluid (r = 0.840, P < 0.0001). For all groups, there was no correlation between alpha-fetoprotein MoM and % alpha-fetoprotein-L2 + L3 in maternal serum and amniotic fluid. The proportion of alpha-fetoprotein-L2 + L3 in maternal serum is an appropriate choice for a trisomy 21 biochemical marker, and it is possible that combining alpha-fetoprotein-L2 + L3 analysis with assays of alpha-fetoprotein in maternal serum could further improve the sensitivity and specificity of multiple marker screening.

  12. [Chromosome abnormalities associated with Phl and acturial survivorship curve in chronic myeloid leukemia. Probabilistic interpretation of blastic transformation of CML].

    PubMed

    Coutris, G

    1981-12-01

    Sixty-six patients with chronic myelogenous leukemia, all with Philadelphia chromosome, have been studied for chromosomic abnormalities associated (CAA) to Ph', as well as for actuarial curve of survivorship. Patients dying from another disease were excluded from this study. Frequency of cells with CAA was measured and appeared strongly higher after blastic transformation than during myelocytic state; probability to be a blastic transformation is closely correlated with this frequency. On the other hand, actuarial curve of survivorship is very well represented by an exponential curve. This suggests a constant rate of death during disease evolution, for these patients without intercurrent disease. As a mean survivance after blastic transformation is very shorter than myelocytic duration, a constant rate of blastic transformation could be advanced: it explains possible occurrence of transformation as soon as preclinic state of a chronic myelogenous leukemia. Even if CAA frequency increases after blastic transformation, CAA can occur a long time before it and do not explain it: submicroscopic origin should be searched for the constant rate of blastic transformation would express the risk of a genic transformation at a constant rate during myelocytic state.

  13. Sexual and individual foraging segregation in Gentoo penguins Pygoscelis papua from the Southern Ocean during an abnormal winter

    PubMed Central

    Trathan, Philip N.; Ceia, Filipe R.; Tarling, Geraint A.; Adlard, Stacey; Fox, Derren; Edwards, Ewan W. J.; Vieira, Rui P.; Medeiros, Renata; De Broyer, Claude; Cherel, Yves

    2017-01-01

    Knowledge about sexual segregation and gender-specific, or indeed individual specialization, in marine organisms has improved considerably in the past decade. In this context, we tested the “Intersexual Competition Hypothesis” for penguins by investigating the feeding ecology of Gentoo penguins during their austral winter non-breeding season. We considered this during unusual environmental conditions (i.e. the year 2009 had observations of high sea surface and air temperatures) in comparison with the long term average at Bird Island, South Georgia. Through conventional (i.e. stomach contents) and stable isotopic values from red blood cells, plasma and feathers of both male and female Gentoo penguins, we showed that there were significant differences between sexes, with males feeding mainly on fish (54% by mass) followed by crustaceans (38%) whereas females fed mainly on crustaceans (89% by mass) followed by fish (4%). Themisto gaudichaudii was the most important crustacean prey for males (64% by mass; 82% by number; 53% by frequency of occurrence) and females (63% by mass; 77% by number; 89% by frequency of occurrence), contrasting with all previous studies that found Antarctic krill Euphausia superba were generally the main prey. Stable isotopic data showed that, in terms of habitat use (based on δ 13C), there were significant differences in short-term carbon signatures between males and females (based on plasma and red blood cells), suggesting that both sexes explored different habitats, with females exploring more offshore pelagic waters and males feeding more in coastal benthic waters. Based on δ 15N, males fed on significantly higher trophic level than females (based on plasma and red blood cells), in agreement with our diet results., Thus, Gentoo penguins behave in a similar manner to other non-breeding penguins species (e.g. king, macaroni and rockhopper penguins), albeit at a smaller spatial scale (as they do not disperse as these other penguins do

  14. Sexual and individual foraging segregation in Gentoo penguins Pygoscelis papua from the Southern Ocean during an abnormal winter.

    PubMed

    Xavier, José C; Trathan, Philip N; Ceia, Filipe R; Tarling, Geraint A; Adlard, Stacey; Fox, Derren; Edwards, Ewan W J; Vieira, Rui P; Medeiros, Renata; De Broyer, Claude; Cherel, Yves

    2017-01-01

    Knowledge about sexual segregation and gender-specific, or indeed individual specialization, in marine organisms has improved considerably in the past decade. In this context, we tested the "Intersexual Competition Hypothesis" for penguins by investigating the feeding ecology of Gentoo penguins during their austral winter non-breeding season. We considered this during unusual environmental conditions (i.e. the year 2009 had observations of high sea surface and air temperatures) in comparison with the long term average at Bird Island, South Georgia. Through conventional (i.e. stomach contents) and stable isotopic values from red blood cells, plasma and feathers of both male and female Gentoo penguins, we showed that there were significant differences between sexes, with males feeding mainly on fish (54% by mass) followed by crustaceans (38%) whereas females fed mainly on crustaceans (89% by mass) followed by fish (4%). Themisto gaudichaudii was the most important crustacean prey for males (64% by mass; 82% by number; 53% by frequency of occurrence) and females (63% by mass; 77% by number; 89% by frequency of occurrence), contrasting with all previous studies that found Antarctic krill Euphausia superba were generally the main prey. Stable isotopic data showed that, in terms of habitat use (based on δ 13C), there were significant differences in short-term carbon signatures between males and females (based on plasma and red blood cells), suggesting that both sexes explored different habitats, with females exploring more offshore pelagic waters and males feeding more in coastal benthic waters. Based on δ 15N, males fed on significantly higher trophic level than females (based on plasma and red blood cells), in agreement with our diet results., Thus, Gentoo penguins behave in a similar manner to other non-breeding penguins species (e.g. king, macaroni and rockhopper penguins), albeit at a smaller spatial scale (as they do not disperse as these other penguins do), in

  15. The Forkhead transcription factor Hcm1 regulates chromosome segregation genes and fills the S-phase gap in the transcriptional circuitry of the cell cycle.

    PubMed

    Pramila, Tata; Wu, Wei; Miles, Shawna; Noble, William Stafford; Breeden, Linda L

    2006-08-15

    Transcription patterns shift dramatically as cells transit from one phase of the cell cycle to another. To better define this transcriptional circuitry, we collected new microarray data across the cell cycle of budding yeast. The combined analysis of these data with three other cell cycle data sets identifies hundreds of new highly periodic transcripts and provides a weighted average peak time for each transcript. Using these data and phylogenetic comparisons of promoter sequences, we have identified a late S-phase-specific promoter element. This element is the binding site for the forkhead protein Hcm1, which is required for its cell cycle-specific activity. Among the cell cycle-regulated genes that contain conserved Hcm1-binding sites, there is a significant enrichment of genes involved in chromosome segregation, spindle dynamics, and budding. This may explain why Hcm1 mutants show 10-fold elevated rates of chromosome loss and require the spindle checkpoint for viability. Hcm1 also induces the M-phase-specific transcription factors FKH1, FKH2, and NDD1, and two cell cycle-specific transcriptional repressors, WHI5 and YHP1. As such, Hcm1 fills a significant gap in our understanding of the transcriptional circuitry that underlies the cell cycle.

  16. Meiotic abnormalities

    SciTech Connect

    NONE

    1993-12-31

    Chapter 19, describes meiotic abnormalities. These include nondisjunction of autosomes and sex chromosomes, genetic and environmental causes of nondisjunction, misdivision of the centromere, chromosomally abnormal human sperm, male infertility, parental age, and origin of diploid gametes. 57 refs., 2 figs., 1 tab.

  17. Parental decisions to abort or continue a pregnancy following prenatal diagnosis of chromosomal abnormalities in a setting where termination of pregnancy is not legally available.

    PubMed

    Quadrelli, Roberto; Quadrelli, Andrea; Mechoso, Búrix; Laufer, Mauricio; Jaumandreu, Ciro; Vaglio, Alicia

    2007-03-01

    To learn about parental decisions to abort or continue a pregnancy after prenatal diagnosis of chromosomal abnormalities among the population in Uruguay. Between 1982 and 2003, 14 656 amniocentesis and 2740 chorionic villus samplings were performed in a referral Genetic Unit. Chromosomal anomalies were found in 376 cases (2.16%) and included Down syndrome, aneuploidies in which a severe prognosis was expected, sex chromosome aneuploidy and aneuploidies with a low risk of an abnormal clinical phenotype. The couples that received abnormal results were contacted by phone and asked if they had continued or interrupted the pregnancy after the diagnosis and genetic counseling. We contacted 207 couples (55%). When confronted with Down syndrome or an aneuploidy in which a severe prognosis was expected, 89% and 96% of patients, respectively, decided to terminate the pregnancy. When confronted with sex chromosome aneuploidy or aneuploidies with a low risk of an abnormal clinical phenotype, 79% and 90% of patients, respectively, decided to continue the pregnancy. The present study shows that when faced with an anomaly such as Down syndrome and aneuploidies in which a severe prognosis was expected, most of the couples decided to terminate the pregnancy, although TOP is not legally available in Uruguay. Copyright (c) 2007 John Wiley & Sons, Ltd.

  18. Second-trimester IL-15 and IL-18 levels in the amniotic fluid of fetuses with normal karyotypes and with chromosome abnormalities.

    PubMed

    Klimkiewicz-Blok, Dominika; Florjański, Jerzy; Zalewski, Jerzy; Blok, Radosław

    2012-01-01

    Little is known about the behavior of interleukin 15 (IL-15) and 18 (IL-18) in the amniotic fluid in the second trimester of gestations complicated by chromosomal defects in the fetus. Likewise, it has not yet been established whether a fetus with chromosome abnormalities creates its immunity mechanisms in the same way as a fetus with a normal karyotype. The aim of this work was to assess the concentration of IL-15 and IL-18 in the amniotic fluid in the second trimester of gestation in fetuses with normal karyotypes and with chromosome abnormalities. The material consisted of 51 samples of amniotic fluid obtained from genetic amniocenteses carried out between the 15th and the 19th weeks of gestation. On the basis of cytogenetic screening, two groups were singled out: Group I--45 fetuses with normal karyotypes, and Group II--6 fetuses with abnormal karyotypes. The concentrations of IL-15 and IL-18 in the amniotic fluid were assessed with ready-made assays and analyzed, and the results from both groups were compared. The differences between the IL-15 levels in the amniotic fluid from Groups I and II proved to be statistically insignificant (p = 0.054). However, the average IL-18 levels in the amniotic fluid of the fetuses with normal karyotypes were significantly higher than in the amniotic fluid of the fetuses with chromosome abnormalities (p = 0.032). Some defense mechanisms in the second trimester of gestation in fetuses with chromosome abnormalities may develop in a different way than in fetuses with normal karyotypes.

  19. Live births after simultaneous avoidance of monogenic diseases and chromosome abnormality by next-generation sequencing with linkage analyses.

    PubMed

    Yan, Liying; Huang, Lei; Xu, Liya; Huang, Jin; Ma, Fei; Zhu, Xiaohui; Tang, Yaqiong; Liu, Mingshan; Lian, Ying; Liu, Ping; Li, Rong; Lu, Sijia; Tang, Fuchou; Qiao, Jie; Xie, X Sunney

    2015-12-29

    In vitro fertilization (IVF), preimplantation genetic diagnosis (PGD), and preimplantation genetic screening (PGS) help patients to select embryos free of monogenic diseases and aneuploidy (chromosome abnormality). Next-generation sequencing (NGS) methods, while experiencing a rapid cost reduction, have improved the precision of PGD/PGS. However, the precision of PGD has been limited by the false-positive and false-negative single-nucleotide variations (SNVs), which are not acceptable in IVF and can be circumvented by linkage analyses, such as short tandem repeats or karyomapping. It is noteworthy that existing methods of detecting SNV/copy number variation (CNV) and linkage analysis often require separate procedures for the same embryo. Here we report an NGS-based PGD/PGS procedure that can simultaneously detect a single-gene disorder and aneuploidy and is capable of linkage analysis in a cost-effective way. This method, called "mutated allele revealed by sequencing with aneuploidy and linkage analyses" (MARSALA), involves multiple annealing and looping-based amplification cycles (MALBAC) for single-cell whole-genome amplification. Aneuploidy is determined by CNVs, whereas SNVs associated with the monogenic diseases are detected by PCR amplification of the MALBAC product. The false-positive and -negative SNVs are avoided by an NGS-based linkage analysis. Two healthy babies, free of the monogenic diseases of their parents, were born after such embryo selection. The monogenic diseases originated from a single base mutation on the autosome and the X-chromosome of the disease-carrying father and mother, respectively.

  20. Inversion of chromosome 7q22 and q36 as a sole abnormality presenting in myelodysplastic syndrome: a case report.

    PubMed

    Kaneko, Hiroto; Shimura, Kazuho; Kuwahara, Saeko; Ohshiro, Muneo; Tsutsumi, Yasuhiko; Iwai, Toshiki; Horiike, Shigeo; Yokota, Shouhei; Ohkawara, Yasuo; Taniwaki, Masafumi

    2014-08-05

    Deletions of chromosome 7 are often detected in myelodysplastic syndrome. The most commonly deleted segments are clustered at band 7q22. A critical gene is therefore suggested to be located in this region. We report a patient with myelodysplastic syndrome whose marrow cells carried an inversion of 7q22 and q36 as a sole karyotypic abnormality. How this extremely rare chromosomal aberration contributes to the pathogenesis of myelodysplastic syndrome should be clarified by accumulating clinical data of such cases. A 74-year-old Japanese man presented with pancytopenia incidentally detected by routine medical check-up. His complete blood cell counts revealed that his white blood cells had decreased to 2100/mm3, neutrophils 940/mm3, red blood cells 320×104/mm3, hemoglobin 11.1g/dL, hematocrit 33.1%, and platelets 12.6×104/mm3. Bone marrow examination showed normal cellularity with nucleated cells of 9.4×104/mm3. The proportion of blasts was 4%. A morphological examination showed only basophilic stippling of erythroblasts which was seen as dysplasia. According to World Health Organization classification, the diagnosis was myelodysplastic syndrome-u. Karyotypic analysis showed 46,XY,inv(7)(q22q36) in all of 20 metaphases examined. Additional analysis revealed the karyotype of his lymphocytes was 46,XY. He is asymptomatic and cytopenia has slowly progressed. To the best of our knowledge, this karyotype from a clinical sample of de novo malignancies has never been documented although the identical karyotype from secondary myelodysplastic syndrome was reported. Despite the extremely low frequency, inversion of 7q22 appears to play a crucial role for myelodysplastic syndrome in this patient.

  1. Chromosomal abnormalities: subgroup analysis by maternal age and perinatal features in zhejiang province of China, 2011-2015.

    PubMed

    Zhang, Xiao-Hui; Qiu, Li-Qian; Ye, Ying-Hui; Xu, Jian

    2017-05-12

    Recently, the prevalence of chromosomal abnormalities (CA) increased as the increasing proportion of mothers with advanced age. We aimed to explore the prevalence of CA in relation to maternal age and perinatal features. A retrospective study was performed based on provincial birth defects surveillance data. The relative risk (RR) and 95% confidence interval (CI) were used to calculate maternal age-specific rates of CA. Socio-demographic characteristics of mothers and perinatal features were listed. The total prevalence of CA was 6.38 per 10,000 births, which increased per 10,000 births linearly from 4.02 in 2011 to 9.13 in 2015 (x 2 line-trend =52.69, p < 0.001). During this period, the prevalence for CA per 10,000 births among women over 35 years old increased from 15.34 in 2011 to 33.82 in 2015 (x 2 line-trend =115121.6, p < 0.001). The RR for overall CA, trisomy 21(T21), trisomy 18(T18) and others in mothers 35 years or older were 6.64 (95% CI 5.55 ~ 7.93), 6.83 (95% CI 5.63 ~ 8.30), 4.06 (95% CI 2.09 ~ 7.90) and 7.54 (95% CI 4.02 ~ 14.11) respectively in comparison to mothers aged 25-29 years old. The stillbirths rate for total CA was 76.45%. T21 and T18 were strongly associated with multiple anomalies, especially congenital heart abnormalities. The prevalence of CA increased as maternal age increased. Cases with CA were associated with other congenital defects and high mortality risk.

  2. Alteration/Deficiency in Activation 3 (ADA3) Protein, a Cell Cycle Regulator, Associates with the Centromere through CENP-B and Regulates Chromosome Segregation.

    PubMed

    Mohibi, Shakur; Srivastava, Shashank; Wang-France, Jun; Mirza, Sameer; Zhao, Xiangshan; Band, Hamid; Band, Vimla

    2015-11-20

    ADA3 (alteration/deficiency in activation 3) is a conserved component of several transcriptional co-activator and histone acetyltransferase (HAT) complexes. Recently, we generated Ada3 knock-out mice and demonstrated that deletion of Ada3 leads to early embryonic lethality. The use of Ada3(FL/FL) mouse embryonic fibroblasts with deletion of Ada3 using adenovirus Cre showed a critical role of ADA3 in cell cycle progression through mitosis. Here, we demonstrate an association of ADA3 with the higher order repeat region of the α-satellite region on human X chromosome centromeres that is consistent with its role in mitosis. Given the role of centromere proteins (CENPs) in mitosis, we next analyzed whether ADA3 associates with the centromere through CENPs. Both an in vivo proximity ligation assay and immunofluorescence studies confirmed the association of ADA3 with CENP-B protein, a highly conserved centromeric protein that binds to the 17-bp DNA sequences on α-satellite DNA. Deletional analysis showed that ADA3 directly associates with CENP-B through its N terminus, and a CENP-B binding-deficient mutant of ADA3 was incompetent in cell proliferation rescue. Notably, knockdown of ADA3 decreased binding of CENP-B onto the centromeres, suggesting that ADA3 is required for the loading of CENP-B onto the centromeres. Finally, we show that deletion of Ada3 from Ada3(FL/FL) mouse embryonic fibroblasts exhibited various chromosome segregation defects. Taken together, we demonstrate a novel ADA3 interaction with CENP-B-centromere that may account for its previously known function in mitosis. This study, together with its known function in maintaining genomic stability and its mislocalization in cancers, suggests an important role of ADA3 in mitosis. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  3. Phenotypic Analysis of Korean Patients with Abnormal Chromosomal Microarray in Patients with Unexplained Developmental Delay/Intellectual Disability.

    PubMed

    Kim, Hyo Jeong; Park, Chang Il; Lim, Jae Woo; Lee, Gyung Min; Cho, Eunhae; Kim, Hyon J

    2018-05-01

    The present study aimed to investigate chromosomal microarray (CMA) and clinical data in patients with unexplained developmental delay/intellectual disability (DD/ID) accompanying dysmorphism, congenital anomalies, or epilepsy. We also aimed to evaluate phenotypic clues in patients with pathogenic copy number variants (CNVs). We collected clinical and CMA data from patients at Konyang University Hospital between September 2013 and October 2014. We included patients who had taken the CMA test to evaluate the etiology of unexplained DD/ID. All of the 50 patients identified had DD/ID. Thirty-nine patients had dysmorphism, 19 patients suffered from epilepsy, and 12 patients had congenital anomalies. Twenty-nine of the 50 patients (58%) showed abnormal results. Eighteen (36%) were considered to have pathogenic CNVs. Dysmorphism (p=0.028) was significantly higher in patients with pathogenic CNVs than in those with normal CMA. Two or more clinical features were presented by 61.9% (13/21) of the patients with normal CMA and by 83.3% (15/18) of the patients with pathogenic CMA. Dysmorphism can be a phenotypic clue to pathogenic CNVs. Furthermore, pathogenic CNV might be more frequently found if patients have two or more clinical features in addition to DD/ID. © Copyright: Yonsei University College of Medicine 2018.

  4. The spatio-temporal dynamics of PKA activity profile during mitosis and its correlation to chromosome segregation.

    PubMed

    Vandame, Pauline; Spriet, Corentin; Trinel, Dave; Gelaude, Armance; Caillau, Katia; Bompard, Coralie; Biondi, Emanuele; Bodart, Jean-François

    2014-01-01

    The cyclic adenosine monophosphate dependent kinase protein (PKA) controls a variety of cellular processes including cell cycle regulation. Here, we took advantages of genetically encoded FRET-based biosensors, using an AKAR-derived biosensor to characterize PKA activity during mitosis in living HeLa cells using a single-cell approach. We measured PKA activity changes during mitosis. HeLa cells exhibit a substantial increase during mitosis, which ends with telophase. An AKAREV T>A inactive form of the biosensor and H89 inhibitor were used to ascertain for the specificity of the PKA activity measured. On a spatial point of view, high levels of activity near to chromosomal plate during metaphase and anaphase were detected. By using the PKA inhibitor H89, we assessed the role of PKA in the maintenance of a proper division phenotype. While this treatment in our hands did not impaired cell cycle progression in a drastic manner, inhibition of PKA leads to a dramatic increase in chromososme misalignement on the spindle during metaphase that could result in aneuploidies. Our study emphasizes the insights that can be gained with genetically encoded FRET-based biosensors, which enable to overcome the shortcomings of classical methologies and unveil in vivo PKA spatiotemporal profiles in HeLa cells.

  5. P38 Mitogen-activated Protein Kinase Activity Is Required during Mitosis for Timely Satisfaction of the Mitotic Checkpoint But Not for the Fidelity of Chromosome Segregation

    PubMed Central

    Lee, Kyunghee; Kenny, Alison E.

    2010-01-01

    Although p38 activity is reported to be required as cells enter mitosis for proper spindle assembly and checkpoint function, its role during the division process remains controversial in lieu of direct data. We therefore conducted live cell studies to determine the effect on mitosis of inhibiting or depleting p38. We found that in the absence of p38 activity the duration of mitosis is prolonged by ∼40% in nontransformed human RPE-1, ∼80% in PtK2 (rat kangaroo), and ∼25% in mouse cells, and this prolongation leads to an elevated mitotic index. However, under this condition chromatid segregation and cytokinesis are normal. Using Mad2/YFP-expressing cells, we show the prolongation of mitosis in the absence of p38 activity is directly due to a delay in satisfying the mitotic checkpoint. Inhibiting p38 did not affect the rate of chromosome motion; however, it did lead to the formation of significantly (10%) longer metaphase spindles. From these data we conclude that normal p38 activity is required for the timely stable attachment of all kinetochores to spindle microtubules, but not for the fidelity of the mitotic process. We speculate that p38 activity promotes timely checkpoint satisfaction by indirectly influencing those motor proteins (e.g., Klp10, Klp67A) involved in regulating the dynamics of kinetochore microtubule ends. PMID:20462950

  6. Evolution and tinkering: what do a protein kinase, a transcriptional regulator and chromosome segregation/cell division proteins have in common?

    PubMed

    Derouiche, Abderahmane; Shi, Lei; Kalantari, Aida; Mijakovic, Ivan

    2016-02-01

    In this study, we focus on functional interactions among multi-domain proteins which share a common evolutionary origin. The examples we develop are four Bacillus subtilis proteins, which all possess an ATP-binding Walker motif: the bacterial tyrosine kinase (BY-kinase) PtkA, the chromosome segregation protein Soj (ParA), the cell division protein MinD and a transcription regulator SalA. These proteins have arisen via duplication of the ancestral ATP-binding domain, which has undergone fusions with other functional domains in the process of divergent evolution. We point out that these four proteins, despite having very different physiological roles, engage in an unusually high number of binary functional interactions. Namely, MinD attracts Soj and PtkA to the cell pole, and in addition, activates the kinase function of PtkA. SalA also activates the kinase function of PtkA, and it gets phosphorylated by PtkA as well. The consequence of this phosphorylation is the activation of SalA as a transcriptional repressor. We hypothesize that these functional interactions remain preserved during divergent evolution and represent a constraint on the process of evolutionary "tinkering", brought about by fusions of different functional domains.

  7. An unconventional interaction between Dis1/TOG and Mal3/EB1 in fission yeast promotes the fidelity of chromosome segregation.

    PubMed

    Matsuo, Yuzy; Maurer, Sebastian P; Yukawa, Masashi; Zakian, Silva; Singleton, Martin R; Surrey, Thomas; Toda, Takashi

    2016-12-15

    Dynamic microtubule plus-ends interact with various intracellular target regions such as the cell cortex and the kinetochore. Two conserved families of microtubule plus-end-tracking proteins, the XMAP215, ch-TOG or CKAP5 family and the end-binding 1 (EB1, also known as MAPRE1) family, play pivotal roles in regulating microtubule dynamics. Here, we study the functional interplay between fission yeast Dis1, a member of the XMAP215/TOG family, and Mal3, an EB1 protein. Using an in vitro microscopy assay, we find that purified Dis1 autonomously tracks growing microtubule ends and is a bona fide microtubule polymerase. Mal3 recruits additional Dis1 to microtubule ends, explaining the synergistic enhancement of microtubule dynamicity by these proteins. A non-canonical binding motif in Dis1 mediates the interaction with Mal3. X-ray crystallography shows that this new motif interacts in an unconventional configuration with the conserved hydrophobic cavity formed within the Mal3 C-terminal region that typically interacts with the canonical SXIP motif. Selectively perturbing the Mal3-Dis1 interaction in living cells demonstrates that it is important for accurate chromosome segregation. Whereas, in some metazoans, the interaction between EB1 and the XMAP215/TOG family members requires an additional binding partner, fission yeast relies on a direct interaction, indicating evolutionary plasticity of this critical interaction module. © 2016. Published by The Company of Biologists Ltd.

  8. Linking topology of tethered polymer rings with applications to chromosome segregation and estimation of the knotting length.

    PubMed

    Marko, John F

    2009-05-01

    The Gauss linking number (Ca) of two flexible polymer rings which are tethered to one another is investigated. For ideal random walks, mean linking-squared varies with the square root of polymer length while for self-avoiding walks, linking-squared increases logarithmically with polymer length. The free-energy cost of linking of polymer rings is therefore strongly dependent on degree of self-avoidance, i.e., on intersegment excluded volume. Scaling arguments and numerical data are used to determine the free-energy cost of fixed linking number in both the fluctuation and large-Ca regimes; for ideal random walks, for |Ca|>N;{1/4} , the free energy of catenation is found to grow proportional, variant|Ca/N;{1/4}|;{4/3} . When excluded volume interactions between segments are present, the free energy rapidly approaches a linear dependence on Gauss linking (dF/dCa approximately 3.7k_{B}T) , suggestive of a novel "catenation condensation" effect. These results are used to show that condensation of long entangled polymers along their length, so as to increase excluded volume while decreasing number of statistical segments, can drive disentanglement if a mechanism is present to permit topology change. For chromosomal DNA molecules, lengthwise condensation is therefore an effective means to bias topoisomerases to eliminate catenations between replicated chromatids. The results for mean-square catenation are also used to provide a simple approximate estimate for the "knotting length," or number of segments required to have a knot along a single circular polymer, explaining why the knotting length ranges from approximately 300 for an ideal random walk to 10;{6} for a self-avoiding walk.

  9. Curcumin-induced mitotic arrest is characterized by spindle abnormalities, defects in chromosomal congression and DNA damage

    PubMed Central

    Manson, Margaret M.

    2013-01-01

    The chemopreventive agent curcumin has anti-proliferative effects in many tumour types, but characterization of cell cycle arrest, particularly with physiologically relevant concentrations, is still incomplete. Following oral ingestion, the highest concentrations of curcumin are achievable in the gut. Although it has been established that curcumin induces arrest at the G2/M stage of the cell cycle in colorectal cancer lines, it is not clear whether arrest occurs at the G2/M transition or in mitosis. To elucidate the precise stage of arrest, we performed a direct comparison of the levels of curcumin-induced G2/M boundary and mitotic arrest in eight colorectal cancer lines (Caco-2, DLD-1, HCA-7, HCT116p53+/+, HCT116p53–/–, HCT116p21–/–, HT-29 and SW480). Flow cytometry confirmed that these lines underwent G2/M arrest following treatment for 12h with clinically relevant concentrations of curcumin (5–10 μM). In all eight lines, the majority of this arrest occurred at the G2/M transition, with a proportion of cells arresting in mitosis. Examination of the mitotic index using fluorescence microscopy showed that the HCT116 and Caco-2 lines exhibited the highest levels of curcumin-induced mitotic arrest. Image analysis revealed impaired mitotic progression in all lines, exemplified by mitotic spindle abnormalities and defects in chromosomal congression. Pre-treatment with inhibitors of the DNA damage signalling pathway abrogated curcumin-induced mitotic arrest, but had little effect at the G2/M boundary. Moreover, pH2A.X staining seen in mitotic, but not interphase, cells suggests that this aberrant mitosis results in DNA damage. PMID:23125222

  10. Mutations reducing replication from R-loops suppress the defects of growth, chromosome segregation and DNA supercoiling in cells lacking topoisomerase I and RNase HI activity.

    PubMed

    Usongo, Valentine; Martel, Makisha; Balleydier, Aurélien; Drolet, Marc

    2016-04-01

    R-loop formation occurs when the nascent RNA hybridizes with the template DNA strand behind the RNA polymerase. R-loops affect a wide range of cellular processes and their use as origins of replication was the first function attributed to them. In Escherichia coli, R-loop formation is promoted by the ATP-dependent negative supercoiling activity of gyrase (gyrA and gyrB) and is inhibited by topoisomerase (topo) I (topA) relaxing transcription-induced negative supercoiling. RNase HI (rnhA) degrades the RNA moiety of R-loops. The depletion of RNase HI activity in topA null mutants was previously shown to lead to extensive DNA relaxation, due to DNA gyrase inhibition, and to severe growth and chromosome segregation defects that were partially corrected by overproducing topo III (topB). Here, DNA gyrase assays in crude cell extracts showed that the ATP-dependent activity (supercoiling) of gyrase but not its ATP-independent activity (relaxation) was inhibited in topA null cells lacking RNase HI. To characterize the cellular event(s) triggered by the absence of RNase HI, we performed a genetic screen for suppressors of the growth defect of topA rnhA null cells. Suppressors affecting genes in replication (holC2::aph and dnaT18::aph) nucleotide metabolism (dcd49::aph), RNA degradation (rne59::aph) and fimbriae synthesis (fimD22::aph) were found to reduce replication from R-loops and to restore supercoiling, thus pointing to a correlation between R-loop-dependent replication in topA rnhA mutants and the inhibition of gyrase activity and growth. Interestingly, the position of fimD on the E. coli chromosome corresponds to the site of one of the five main putative origins of replication from R-loops in rnhA null cells recently identified by next-generation sequencing, thus suggesting that the fimD22::aph mutation inactivated one of these origins. Furthermore, we show that topo III overproduction is unable to complement the growth defect of topA rnhA null mutants at low

  11. The potential impact of NIPT as a second-tier screen on the outcomes of high-risk pregnancies with rare chromosomal abnormalities.

    PubMed

    Maxwell, Susannah; Dickinson, Jan E; Murch, Ashleigh; O'Leary, Peter

    2015-10-01

    To describe the potential impact of using noninvasive prenatal testing (NIPT) as a second-tier test, on the diagnosis and outcomes of pregnancies identified as high risk through first trimester screening (FTS) in a cohort of real pregnancies. Western Australian FTS and diagnostic data (2007-2009) were linked to pregnancy outcomes. Karyotype results from invasive prenatal testing in high-risk women were analysed. The outcomes of abnormal results that would not be detected by NIPT, assuming a panel of trisomy 21/18/13 and sex chromosome aneuploidies, and the likelihood of diagnosis in a screening model using NIPT as a second-tier test are described. Abnormal karyotype results were reported in 224 of 1488 (15%) women with high-risk pregnancies having invasive diagnostic testing. NIPT potentially would have identified 85%. The 33 abnormalities unidentifiable by NIPT were triploidies (n = 7, 21%), balanced (n = 8, 24%) and unbalanced rearrangements (n = 10, 30%) and level III mosaicisms (n = 8, 24%). For conditions not identifiable by NIPT, fetal sonographic appearance was likely to have led to invasive testing for 10 of 17 (59%) pathogenic abnormalities. If a policy was adopted recommending invasive testing for FTS risk >1:50 and/or ultrasound detected abnormality, the residual risk of an unidentified pathogenic chromosomal abnormality in those without a diagnosis would have been 0.33% (95% CI 0.01-0.65%). A screening model with NIPT as a second-tier for high-risk pregnancies would be unlikely to have changed the outcome for the majority of pregnancies. Optimising the diagnosis of rare pathogenic abnormalities requires clear indicators for invasive testing over NIPT. © 2015 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.

  12. Identification of the CIMP-like subtype and aberrant methylation of members of the chromosomal segregation and spindle assembly pathways in esophageal adenocarcinoma.

    PubMed

    Krause, Lutz; Nones, Katia; Loffler, Kelly A; Nancarrow, Derek; Oey, Harald; Tang, Yue Hang; Wayte, Nicola J; Patch, Ann Marie; Patel, Kalpana; Brosda, Sandra; Manning, Suzanne; Lampe, Guy; Clouston, Andrew; Thomas, Janine; Stoye, Jens; Hussey, Damian J; Watson, David I; Lord, Reginald V; Phillips, Wayne A; Gotley, David; Smithers, B Mark; Whiteman, David C; Hayward, Nicholas K; Grimmond, Sean M; Waddell, Nicola; Barbour, Andrew P

    2016-04-01

    The incidence of esophageal adenocarcinoma (EAC) has risen significantly over recent decades. Although survival has improved, cure rates remain poor, with <20% of patients surviving 5 years. This is the first study to explore methylome, transcriptome and ENCODE data to characterize the role of methylation in EAC. We investigate the genome-wide methylation profile of 250 samples including 125 EAC, 19 Barrett's esophagus (BE), 85 squamous esophagus and 21 normal stomach. Transcriptome data of 70 samples (48 EAC, 4 BE and 18 squamous esophagus) were used to identify changes in methylation associated with gene expression. BE and EAC showed similar methylation profiles, which differed from squamous tissue. Hypermethylated sites in EAC and BE were mainly located in CpG-rich promoters. A total of 18575 CpG sites associated with 5538 genes were differentially methylated, 63% of these genes showed significant correlation between methylation and mRNA expression levels. Pathways involved in tumorigenesis including cell adhesion, TGF and WNT signaling showed enrichment for genes aberrantly methylated. Genes involved in chromosomal segregation and spindle formation were aberrantly methylated. Given the recent evidence that chromothripsis may be a driver mechanism in EAC, the role of epigenetic perturbation of these pathways should be further investigated. The methylation profiles revealed two EAC subtypes, one associated with widespread CpG island hypermethylation overlapping H3K27me3 marks and binding sites of the Polycomb proteins. These subtypes were supported by an independent set of 89 esophageal cancer samples. The most hypermethylated tumors showed worse patient survival. © The Author 2016. Published by Oxford University Press.

  13. Mammalian Polo-like Kinase 1 (Plk1) Promotes Proper Chromosome Segregation by Phosphorylating and Delocalizing the PBIP1·CENP-Q Complex from Kinetochores

    PubMed Central

    Park, Chi Hoon; Park, Jung-Eun; Kim, Tae-Sung; Kang, Young Hwi; Soung, Nak-Kyun; Zhou, Ming; Kim, Nam-Hyung; Bang, Jeong Kyu; Lee, Kyung S.

    2015-01-01

    Mammalian Plk1 is critically required for proper M phase progression. Plk1 is self-recruited to prekinetochores/kinetochores by phosphorylating and binding to the Thr-78 motif of a kinetochore scaffold protein, PBIP1 (also called CENP-U/50), which forms a stable complex with another kinetochore component, CENP-Q. However, the mechanism regulating Plk1 localization to this site remains largely unknown. Here, we demonstrate that the PBIP1·CENP-Q complex became hyperphosphorylated and rapidly delocalized from kinetochores as cells entered mitosis. Plk1 phosphorylated the CENP-Q subunit of the PBIP1·CENP-Q complex at multiple sites, and mutation of nine Plk1-dependent phosphorylation sites to Ala (9A) enhanced CENP-Q association with chromatin and prolonged CENP-Q localization to kinetochores. Conversely, mutation of the nine sites to phospho-mimicking Asp/Glu (9D/E) residues dissociated CENP-Q from chromatin and kept the CENP-Q(9D/E) mutant from localizing to interphase prekinetochores. Strikingly, both the 9A and 9D/E mutants induced a defect in proper chromosome segregation, suggesting that both timely localization of the PBIP1·CENP-Q complex to prekinetochores and delocalization from kinetochores are critical for normal M phase progression. Notably, although Plk1 did not alter the level of PBIP1 and CENP-Q ubiquitination, Plk1-dependent phosphorylation and delocalization of these proteins from kinetochores appeared to indirectly lead to their degradation in the cytosol. Thus, we propose that Plk1 regulates the timing of the delocalization and ultimate destruction of the PBIP1·CENP-Q complex and that these processes are important not only for promoting Plk1-dependent mitotic progression, but also for resetting the timing of Plk1 recruitment to prekinetochores in the next cell cycle. PMID:25670858

  14. Four small supernumerary marker chromosomes derived from chromosomes 6, 8, 11 and 12 in a patient with minimal clinical abnormalities: a case report

    PubMed Central

    2010-01-01

    Introduction Small supernumerary marker chromosomes are still a problem in cytogenetic diagnostic and genetic counseling. This holds especially true for the rare cases with multiple small supernumerary marker chromosomes. Most such cases are reported to be clinically severely affected due to the chromosomal imbalances induced by the presence of small supernumerary marker chromosomes. Here we report the first case of a patient having four different small supernumerary marker chromosomes which, apart from slight developmental retardation in youth and non-malignant hyperpigmentation, presented no other clinical signs. Case presentation Our patient was a 30-year-old Caucasian man, delivered by caesarean section because of macrosomy. At birth he presented with bilateral cryptorchidism but no other birth defects. At age of around two years he showed psychomotor delay and a bilateral convergent strabismus. Later he had slight learning difficulties, with normal social behavior and now lives an independent life as an adult. Apart from hypogenitalism, he has multiple hyperpigmented nevi all over his body, short feet with pes cavus and claw toes. At age of 30 years, cytogenetic and molecular cytogenetic analysis revealed a karyotype of 50,XY,+min(6)(:p11.1-> q11.1:),+min(8)(:p11.1->q11.1:),+min(11)(:p11.11->q11:),+min(12)(:p11.2~12->q10:), leading overall to a small partial trisomy in 12p11.1~12.1. Conclusions Including this case, four single case reports are available in the literature with a karyotype 50,XN,+4mar. For prenatally detected multiple small supernumerary marker chromosomes in particular we learn from this case that such a cytogenetic condition may be correlated with a positive clinical outcome. PMID:20682055

  15. A unique case of a discontinuous duplication 3q26.1-3q28 resulting from a segregation error of a maternal complex chromosomal rearrangement involving an insertion and an inversion.

    PubMed

    Rodríguez, Laura; Bhatt, Samarth S; García-Castro, Mónica; Plasencia, Ana; Fernández-Toral, Joaquín; Abarca, Elena; de Bello Cioffi, Marcelo; Liehr, Thomas

    2014-02-10

    Until now, few cases of partial trisomy of 3q due to segregation error of parental balanced translocation and segregation of a duplicated deficient product resulting from parental pericentric inversion have been reported so far. Only five cases of chromosomal insertion malsegregation involving 3q region are available yet, thus making it relatively rare. In this case report, we are presenting a unique case of discontinuous partial trisomy of 3q26.1-q28 region which resulted from a segregation error of two insertions involving 3q26.1 to 3q27.3 and 3q28 regions with ~21Mb and ~2Mb sizes, respectively. The maternally inherited insertion was cytogenetically characterized as der(8)(8pter→8p22::3q26→3q27.3::3q28→3q28::8p22→8qter) and the patient's major clinical features involved Dandy Walker malformation, sub-aortic ventricular septal defect, upslanting palpebral fissures, clinodactyly, hirsutism, and prominent forehead. Besides, a review of the literature involving cases with similar chromosomal imbalances and cases with "3q-duplication syndrome" is also provided. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Only a minority of sex chromosome abnormalities are detected by a national prenatal screening program for Down syndrome.

    PubMed

    Viuff, Mette Hansen; Stochholm, Kirstine; Uldbjerg, Niels; Nielsen, Birgitte Bruun; Gravholt, Claus Højbjerg

    2015-10-01

    How does a national prenatal screening program for Down syndrome (DS) perform in detecting sex chromosome abnormalities (SCAs)-Turner syndrome (TS), Klinefelter syndrome, 47,XXX and 47,XYY syndromes. The SCA detection rate resulting from DS screening was below 50% for all four groups of SCAs. The detection rates of SCAs are higher in countries with DS screening. TS is associated with greater nuchal translucency (NT) and lower pregnancy-associated plasma protein-A (PAPP-A). However, specific detection rates of SCAs using prenatal DS screening have not been determined. No clear trend in PAPP-A, free beta human chorionic gonadotropin (β-hCG) and NT has been found in the remaining SCAs. Several lines of inquiry suggest that it would be advantageous for individuals with SCA to be detected early in life, leading to prevention or treatment of accompanying conditions. There is limited information about pre- and perinatal status that distinguishes SCA embryogenesis from normal fetal development. A register-based case-control study from the Danish Central Cytogenetic Register (DCCR), cross-linked with the Danish Fetal Medicine Database (DFMD), was performed from 2008 to 2012. Groups of SCAs were compared with DS and then matched with non-SCA controls to assess differences between these groups in prenatal markers and birth outcomes. We included cases with prenatal and post-natal SCA karyotypes (n = 213), DS (n = 802) and 168 056 controls. We screened 275 037 individuals examined prenatally. We retrieved information regarding maternal age, NT, β-hCG and PAPP-A, as well as details regarding maternal and newborn characteristics. The DS screening procedure detected 87 per 100 000 TS (42% of expected), 19 per 100 000 Klinefelter syndrome (13% of expected), 16 per 100 000 47,XXX (16% of cases) and 5 per 100 000 47,XYY (5% of expected) SCAs, with an overall detection rate of 27%. Compared with controls, all four SCA groups showed significantly higher NT and lower PAPP-A compared

  17. A Role for the Chaperone Complex BAG3-HSPB8 in Actin Dynamics, Spindle Orientation and Proper Chromosome Segregation during Mitosis.

    PubMed

    Fuchs, Margit; Luthold, Carole; Guilbert, Solenn M; Varlet, Alice Anaïs; Lambert, Herman; Jetté, Alexandra; Elowe, Sabine; Landry, Jacques; Lavoie, Josée N

    2015-10-01

    The co-chaperone BAG3, in complex with the heat shock protein HSPB8, plays a role in protein quality control during mechanical strain. It is part of a multichaperone complex that senses damaged cytoskeletal proteins and orchestrates their seclusion and/or degradation by selective autophagy. Here we describe a novel role for the BAG3-HSPB8 complex in mitosis, a process involving profound changes in cell tension homeostasis. BAG3 is hyperphosphorylated at mitotic entry and localizes to centrosomal regions. BAG3 regulates, in an HSPB8-dependent manner, the timely congression of chromosomes to the metaphase plate by influencing the three-dimensional positioning of the mitotic spindle. Depletion of BAG3 caused defects in cell rounding at metaphase and dramatic blebbing of the cortex associated with abnormal spindle rotations. Similar defects were observed upon silencing of the autophagic receptor p62/SQSTM1 that contributes to BAG3-mediated selective autophagy pathway. Mitotic cells depleted of BAG3, HSPB8 or p62/SQSTM1 exhibited disorganized actin-rich retraction fibres, which are proposed to guide spindle orientation. Proper spindle positioning was rescued in BAG3-depleted cells upon addition of the lectin concanavalin A, which restores cortex rigidity. Together, our findings suggest the existence of a so-far unrecognized quality control mechanism involving BAG3, HSPB8 and p62/SQSTM1 for accurate remodelling of actin-based mitotic structures that guide spindle orientation.

  18. A Role for the Chaperone Complex BAG3-HSPB8 in Actin Dynamics, Spindle Orientation and Proper Chromosome Segregation during Mitosis

    PubMed Central

    Fuchs, Margit; Lambert, Herman; Jetté, Alexandra; Elowe, Sabine; Landry, Jacques; Lavoie, Josée N.

    2015-01-01

    The co-chaperone BAG3, in complex with the heat shock protein HSPB8, plays a role in protein quality control during mechanical strain. It is part of a multichaperone complex that senses damaged cytoskeletal proteins and orchestrates their seclusion and/or degradation by selective autophagy. Here we describe a novel role for the BAG3-HSPB8 complex in mitosis, a process involving profound changes in cell tension homeostasis. BAG3 is hyperphosphorylated at mitotic entry and localizes to centrosomal regions. BAG3 regulates, in an HSPB8-dependent manner, the timely congression of chromosomes to the metaphase plate by influencing the three-dimensional positioning of the mitotic spindle. Depletion of BAG3 caused defects in cell rounding at metaphase and dramatic blebbing of the cortex associated with abnormal spindle rotations. Similar defects were observed upon silencing of the autophagic receptor p62/SQSTM1 that contributes to BAG3-mediated selective autophagy pathway. Mitotic cells depleted of BAG3, HSPB8 or p62/SQSTM1 exhibited disorganized actin-rich retraction fibres, which are proposed to guide spindle orientation. Proper spindle positioning was rescued in BAG3-depleted cells upon addition of the lectin concanavalin A, which restores cortex rigidity. Together, our findings suggest the existence of a so-far unrecognized quality control mechanism involving BAG3, HSPB8 and p62/SQSTM1 for accurate remodelling of actin-based mitotic structures that guide spindle orientation. PMID:26496431

  19. Sequencing of a Patient with Balanced Chromosome Abnormalities and Neurodevelopmental Disease Identifies Disruption of Multiple High Risk Loci by Structural Variation

    PubMed Central

    Blake, Jonathon; Riddell, Andrew; Theiss, Susanne; Gonzalez, Alexis Perez; Haase, Bettina; Jauch, Anna; Janssen, Johannes W. G.; Ibberson, David; Pavlinic, Dinko; Moog, Ute; Benes, Vladimir; Runz, Heiko

    2014-01-01

    Balanced chromosome abnormalities (BCAs) occur at a high frequency in healthy and diseased individuals, but cost-efficient strategies to identify BCAs and evaluate whether they contribute to a phenotype have not yet become widespread. Here we apply genome-wide mate-pair library sequencing to characterize structural variation in a patient with unclear neurodevelopmental disease (NDD) and complex de novo BCAs at the karyotype level. Nucleotide-level characterization of the clinically described BCA breakpoints revealed disruption of at least three NDD candidate genes (LINC00299, NUP205, PSMD14) that gave rise to abnormal mRNAs and could be assumed as disease-causing. However, unbiased genome-wide analysis of the sequencing data for cryptic structural variation was key to reveal an additional submicroscopic inversion that truncates the schizophrenia- and bipolar disorder-associated brain transcription factor ZNF804A as an equally likely NDD-driving gene. Deep sequencing of fluorescent-sorted wild-type and derivative chromosomes confirmed the clinically undetected BCA. Moreover, deep sequencing further validated a high accuracy of mate-pair library sequencing to detect structural variants larger than 10 kB, proposing that this approach is powerful for clinical-grade genome-wide structural variant detection. Our study supports previous evidence for a role of ZNF804A in NDD and highlights the need for a more comprehensive assessment of structural variation in karyotypically abnormal individuals and patients with neurocognitive disease to avoid diagnostic deception. PMID:24625750

  20. Enhanced Detection of Chromosomal Abnormalities in Chronic Lymphocytic Leukemia by Conventional Cytogenetics Using CpG Oligonucleotide in Combination with Pokeweed Mitogen and Phorbol Myristate Acetate

    PubMed Central

    Muthusamy, Natarajan; Breidenbach, Heather; Andritsos, Leslie; Flynn, Joseph; Jones, Jeffrey; Ramanunni, Asha; Mo, Xiaokui; Jarjoura, David; Byrd, John C.; Heerema, Nyla A.

    2011-01-01

    Reproducible cytogenetic analysis in CLL has been limited by the inability to obtain reliable metaphase cells for analysis. CpG oligonucleotide and cytokine stimulation have been shown to improve metaphase analysis of CLL cytogenetic abnormalities, but is limited by variability in the cytokine receptor levels, stability and biological activity of the cytokine in culture conditions and high costs associated with these reagents. We report here use of a novel, stable CpG, GNKG168 along with pokeweed mitogen (PWM) and phorbol 12-myristate 13-acetate (PMA) for conventional cytogenetic assessment in CLL. We demonstrate that the combined use of GNKG168+PWM/PMA increased the sensitivity of detection of chromosomal abnormalities compared to PWM/PMA (n=207, odds ratio=2.2, p=0.0002) and GNKG168 (n=219, odds ratio=1.5, p=0.0452). Further, a significant increase in sensitivity to detect complexity ≥3 with GNKG168+PWM/PMA compared to GNKG168 alone (odds ratio 8.0, p=0.0022) or PWM/PMA alone (odds ratio 9.6, p=0.0007) was observed. The trend toward detection of higher complexity was significantly greater with GNKG168+PWM/PMA compared to GNKG168 alone (p=0.0412). The increased sensitivity was mainly attributed to the addition of PWM/PMA with GNKG168 because GNKG168 alone showed no difference in sensitivity for detection of complex abnormalities (p=0.17). Comparison of fluorescence in situ hybridization (FISH) results with karyotypic results showed a high degree of consistency, although some complex karyotypes were present in cases with no adverse FISH abnormality. These studies provide evidence for potential use of GNKG168 in combination with PWM and PMA in karyotypic analysis of CLL patient samples to better identify chromosomal abnormalities for risk stratification. PMID:21494579

  1. Abnormal proliferation of CD4- CD8+ gammadelta+ T cells with chromosome 6 anomaly: role of Fas ligand expression in spontaneous regression of the cells.

    PubMed

    Ichikawa, N; Kitano, K; Ito, T; Nakazawa, T; Shimodaira, S; Ishida, F; Kiyosawa, K

    1999-04-01

    We report a case of granular lymphocyte proliferative disorder accompanied with hemolytic anemia and neutropenia. Phenotypes of the cells were T cell receptor gammadelta+ CD3+ CD4- CD8+ CD16+ CD56- CD57-. Southern blot analysis of T cell receptor beta and gamma chains demonstrated rearranged bands in both. Chromosomal analysis after IL-2 stimulation showed deletion of chromosome 6. Sorted gammadelta+ T cells showed an increase in Fas ligand expression compared with the levels in sorted alphabeta+ T cells. The expression of Fas ligand on these gammadelta+ T cells increased after IL-2 stimulation. The patient's anemia improved along with a decrease in granular lymphocyte count and disappearance of the abnormal karyotype without treatment. The expression of Fas ligand may be involved in spontaneous regression of granular lymphocyte proliferation with hemolytic anemia.

  2. Sustained trilineage recovery and disappearance of abnormal chromosome clone in a patient with myelodysplastic syndrome following combination therapy with cytokines (granulocyte colony-stimulating factor and erythropoietin) and high-dose methylprednisolone.

    PubMed

    Imai, Y; Fukuoka, T; Nakatani, A; Ohsaka, A; Takahashi, A

    1996-04-01

    We report a case of hypoplastic myelodyplastic syndrome (MDS) (refractory anemia (RA)) in which sustained trilineage haematological response and persistent disappearance of an abnormal chromosome clone were achieved after treatment with combination therapy of cytokines (granulocyte colony-stimulating factor (G-CSF) and erythropoietin (Epo)) and methylprednisolone (mPSL) pulse dose. The patient's haematological recovery was rapid and maintained even after cessation of the therapy. In addition, the predominant chromosome clone 13q- in bone marrow cells disappeared in the fourth week. The patient's improved bone marrow haemopoiesis and disappearance of the abnormal chromosome has continued to the present, 13 months after treatment. The occurrence of both trilineage response and abnormal chromosome disappearance in MDS patients treated with cytokine(s) or steroids is rare. Combination therapy might therefore be advantageous in MDS.

  3. Live-cell imaging of nuclear-chromosomal dynamics in bovine in vitro fertilised embryos.

    PubMed

    Yao, Tatsuma; Suzuki, Rie; Furuta, Natsuki; Suzuki, Yuka; Kabe, Kyoko; Tokoro, Mikiko; Sugawara, Atsushi; Yajima, Akira; Nagasawa, Tomohiro; Matoba, Satoko; Yamagata, Kazuo; Sugimura, Satoshi

    2018-05-10

    Nuclear/chromosomal integrity is an important prerequisite for the assessment of embryo quality in artificial reproductive technology. However, lipid-rich dark cytoplasm in bovine embryos prevents its observation by visible light microscopy. We performed live-cell imaging using confocal laser microscopy that allowed long-term imaging of nuclear/chromosomal dynamics in bovine in vitro fertilised (IVF) embryos. We analysed the relationship between nuclear/chromosomal aberrations and in vitro embryonic development and morphological blastocyst quality. Three-dimensional live-cell imaging of 369 embryos injected with mRNA encoding histone H2B-mCherry and enhanced green fluorescent protein (EGFP)-α-tubulin was performed from single-cell to blastocyst stage for eight days; 17.9% reached the blastocyst stage. Abnormalities in the number of pronuclei (PN), chromosomal segregation, cytokinesis, and blastomere number at first cleavage were observed at frequencies of 48.0%, 30.6%, 8.1%, and 22.2%, respectively, and 13.0%, 6.2%, 3.3%, and 13.4%, respectively, for abnormal embryos developed into blastocysts. A multivariate analysis showed that abnormal chromosome segregation (ACS) and multiple PN correlated with delayed timing and abnormal blastomere number at first cleavage, respectively. In morphologically transferrable blastocysts, 30-40% of embryos underwent ACS and had abnormal PN. Live-cell imaging may be useful for analysing the association between nuclear/chromosomal dynamics and embryonic development in bovine embryos.

  4. Comparison of DNA aneuploidy, chromosome 1 abnormalities, MYCN amplification and CD44 expression as prognostic factors in neuroblastoma.

    PubMed

    Christiansen, H; Sahin, K; Berthold, F; Hero, B; Terpe, H J; Lampert, F

    1995-01-01

    A comparison of the prognostic impact of five molecular variables in a large series was made, including tests of their nonrandom association and multivariate analysis. Molecular data were available for 377 patients and MYCN amplification, cytogenetic chromosome 1p deletion, loss of chromosome 1p heterozygosity, DNA ploidy and CD44 expression were investigated. Their interdependence and influence on event-free survival was tested uni- and multivariately using Pearson's chi 2-test, Kaplan-Meier estimates, log rank tests and the Cox's regression model. MYCN amplification was present in 18% (58/322) of cases and predicted poorer prognosis in localised (P < 0.001), metastatic (P = 0.002) and even 4S (P = 0.040) disease. CD44 expression was found in 86% (127/148) of cases, and was a marker for favourable outcome in patients with neuroblastoma stages 1-3 (P = 0.003) and 4 (P = 0.017). Chromosome 1p deletion was cytogenetically detected in 51% (28/55), and indicated reduced event-free survival in localised neuroblastoma (P = 0.020). DNA ploidy and loss of heterozygosity on chromosome 1p were of less prognostic value. Most factors of prognostic significance were associated with each other. By multivariate analysis, MYCN was selected as the only relevant factor. Risk estimation of high discriminating power is, therefore, possible for patients with localised and metastatic neuroblastoma using stage and MYCN.

  5. BubR1- and Polo-Coated DNA Tethers Facilitate Poleward Segregation of Acentric Chromatids

    PubMed Central

    Royou, Anne; Gagou, Mary E.; Karess, Roger; Sullivan, William

    2010-01-01

    Summary The mechanisms that safeguard cells against chromosomal instability (CIN) are of great interest, as CIN contributes to tumorigenesis. To gain insight into these mechanisms, we studied the behavior of cells entering mitosis with damaged chromosomes. We used the endonuclease I-CreI to generate acentric chromosomes in Drosophila larvae. While I-CreI expression produces acentric chromosomes in the majority of neuronal stem cells, remarkably, it has no effect on adult survival. Our live studies reveal that acentric chromatids segregate efficiently to opposite poles. The acentric chromatid poleward movement is mediated through DNA tethers decorated with BubR1, Polo, INCENP, and Aurora-B. Reduced BubR1 or Polo function results in abnormal segregation of acentric chromatids, a decrease in acentric chromosome tethering, and a great reduction in adult survival. We propose that BubR1 and Polo facilitate the accurate segregation of acentric chromatids by maintaining the integrity of the tethers that connect acentric chromosomes to their centric partners. PMID:20141837

  6. Remission induction of refractory anaemia with excess blasts in transformation by sole treatment with granulocyte colony-stimulating factor with persistent chromosomal abnormality.

    PubMed

    Kondo, Haruki; Kasahara, Yasunori; Mori, Akinori

    2002-01-01

    We report a patient with myelodysplastic syndrome (MDS), refractory anaemia with excess blasts in transformation, in whom complete remission (CR) was achieved with the administration of granulocyte colony-stimulating factor (G-CSF). The 76-year-old patient was admitted to our hospital with a fever and a productive cough; a diagnosis of pneumonia was thus made. Following treatment with antibiotics, the patient's condition improved, and MDS was diagnosed from peripheral blood and bone marrow examinations after the patient recovered from the infection. The patient achieved a sustained haematological CR that was confirmed by morphological and flow cytometric examination after treatment with G-CSF alone, although chromosomal abnormalities persisted. According to the literature, in almost all patients with acute myeloid leukaemia or MDS who were reported to achieve CR by G-CSF, the course was associated with infection, although our case did not have this complication during the course of G-CSF therapy. We suggest that patients with G-CSF alone without infection can achieve CR and that this may be related to a differentiation effect of G-CSF based on persistent chromosomal abnormality in this case. Copyright 2002 S. Karger AG, Basel

  7. Detection of chromosomal abnormalities by fluorescent in-situ hybridization in immotile viable spermatozoa determined by hypo-osmotic sperm swelling test.

    PubMed

    Zeyneloglu, H B; Baltaci, V; Ege, S; Haberal, A; Batioglu, S

    2000-04-01

    If randomly selected immotile spermatozoa are used for intracytoplasmic sperm injection (ICSI), pregnancy rates are significantly decreased. The hypo-osmotic swelling test (HOST) is the only method available to detect the viable, but immotile spermatozoa for ICSI. However, evidence is still lacking for the chromosomal abnormalities for the normal-looking, but immotile spermatozoa positive for HOST. Sperm samples from 20 infertile men with normal chromosomal constitution were obtained. After Percoll separation, morphologically normal but immotile spermatozoa were transported individually into HOST solution for 1 min using micropipettes. Cells that showed tail curling with swelling in HOST were then transferred back into human tubal fluid solution to allow reversal of swelling. These sperm cells were fixed and processed for the multi-colour fluorescence in-situ hybridization (FISH) for chromosomes X, Y and 18. The same FISH procedure was applied for the motile spermatozoa from the same cohort, which formed the control group. The average aneuploidy rates were 1.70 and 1.54% in 1000 HOST positive immotile and motile spermatozoa respectively detected by FISH for each patient. Our results indicate that morphologically normal, immotile but viable spermatozoa have an aneuploidy rate similar to that of normal motile spermatozoa.

  8. The long-term clinical implications of clonal chromosomal abnormalities in newly diagnosed chronic phase chronic myeloid leukemia patients treated with imatinib mesylate.

    PubMed

    Lee, Sung-Eun; Choi, Soo Young; Bang, Ju-Hee; Kim, Soo-Hyun; Jang, Eun-Jung; Byeun, Ji-Young; Park, Jin Eok; Jeon, Hye-Rim; Oh, Yun Jeong; Kim, Myungshin; Kim, Dong-Wook

    2012-11-01

    The aim of this study was to evaluate the long-term clinical significance of an additional chromosomal abnormality (ACA), variant Philadelphia chromosome (vPh) at diagnosis, and newly developed other chromosomal abnormalities (OCA) in patients with chronic myeloid leukemia (CML) on imatinib (IM) therapy. Sequential cytogenetic data from 281 consecutive new chronic phase CML patients were analyzed. With a median follow-up of 78.6 months, the 22 patients with vPh (P = 0.034) or ACA (P = 0.034) at diagnosis had more events of IM failure than did the patients with a standard Ph. The 5-year overall survival (OS), event-free survival (EFS), and failure-free survival (FFS) rates for patients with vPh at diagnosis were 77.8%, 75.0%, and 53.3%, respectively; for patients with ACA at diagnosis, 100%, 66.3%, and 52.1%, respectively; and for patients with a standard Ph, 96.0%, 91.3%, and 83.7%, respectively. During IM therapy, eight patients developed an OCA, which had no impact on outcomes as a time-dependent covariate in our Cox proportional hazards regression models. This study showed that vPh was associated with poor OS and FFS and that ACA had adverse effects on EFS and FFS. In addition, no OCA, except monosomy 7, had any prognostic impact, suggesting that the development of OCA may not require a change in treatment strategy. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Cloning a balanced t(9;11)(p24;q23.1) chromosomal translocation breakpoint segregating with bipolar affective disorder in a small pedigree

    SciTech Connect

    Duggan, D.J.; Baysal, B.E.; Gollin, S.M.

    A small multigenerational pedigree was previously identified in which a balanced 9;11 chromosomal translocation was cosegregating with bipolar affective disorder. We hypothesize that genes or gene regulatory sequences disrupted by the translocation are contributing to bipolar affective disorder in a dominant fashion. The general strategy involves (1) using somatic cell hybrids containing the derivative 9 or 11 chromosomes to identify the closest chromosome 9 and 11 flanking markers, (2) using the nearest markers as PCR and hybridization probes to isolate both normal DNA (YAC) and patient DNA (cosmid) adjacent to and incorporating the translocation breakpoint, and (3) identifying expressed sequencesmore » in the genomic DNA that may be disrupted by the translocation. From a fusion of the translocation patient cell line and a recipient hamster cell line, somatic cell hybrids were isolated which contain either the human derivative 9 or derivative 11 chromosome. Using PCR-based STS assays with these hybrids, the location of the translocation breakpoint was localized to an estimated 500 kb region at chromosome 11 band q23.1 and a 1 cM region in 9 band p24 (more telomeric than originally reported). From a large set of CEPH and Roswell Park yeast artificial chromosomes (YACs), six chromosome 11 YACs spanning the 11q23.1 breakpoint have now been identified. A combination of pulsed field gel eletrophoresis and YAC mapping has narrowed the chromosome 11 region to less than 430 kb. Current efforts are focused on generating new chromosome 11 probes within the flanking markers, mapping these probes back to the der(9) and der(11) containing hybrids and the chromosome 11 YAC mapping panel. As the region is physically narrowed, we will identify candidate genes whose expression may be altered by this t(9:11) translocation.« less

  10. The Argonaute protein TbAGO1 contributes to large and mini-chromosome segregation and is required for control of RIME retroposons and RHS pseudogene-associated transcripts.

    PubMed

    Durand-Dubief, Mickaël; Absalon, Sabrina; Menzer, Linda; Ngwabyt, Sandra; Ersfeld, Klaus; Bastin, Philippe

    2007-12-01

    The protist Trypanosoma brucei possesses a single Argonaute gene called TbAGO1 that is necessary for RNAi silencing. We previously showed that in strain 427, TbAGO1 knock-out leads to a slow growth phenotype and to chromosome segregation defects. Here we report that the slow growth phenotype is linked to defects in segregation of both large and mini-chromosome populations, with large chromosomes being the most affected. These phenotypes are completely reversed upon inducible re-expression of TbAGO1 fused to GFP, demonstrating their link with TbAGO1. Trypanosomes that do not express TbAGO1 show a general increase in the abundance of transcripts derived from the short retroposon RIME (Ribosomal Interspersed Mobile Element). Supplementary large RIME transcripts emerge in the absence of RNAi, a phenomenon coupled to the disappearance of short transcripts. These fluctuations are reversed by inducible expression of GFP::TbAGO1. Furthermore, we use a combination of Northern blots, RT-PCR and sequencing to reveal that RNAi controls expression of transcripts derived from RHS (Retrotransposon Hot Spot) pseudogenes (RHS genes with retro-element(s) integrated within their coding sequence). Absence of RNAi also leads to an increase of steady-state transcripts from regular RHS genes (those without retro-element), indicating a role for pseudogene in control of gene expression. However, analysis of retroposon abundance and arrangement in the genome of multiple clonal cell lines of TbAGO1-/- failed to reveal movement of mobile elements despite the increased amounts of retroposon transcripts.

  11. Possible influences on the expression of X chromosome-linked dystrophin abnormalities by heterozygosity for autosomal recessive Fukuyama congenital muscular dystrophy

    SciTech Connect

    Beggs, A.H.; Neumann, P.E.; Anderson, M.S.

    1992-01-15

    Abnormalities of dystrophin, a cytoskeletal protein of muscle and nerve, are generally considered specific for Duchenne and Becker muscular dystrophy. However, several patients have recently been identified with dystrophin deficiency who, before dystrophin testing, were considered to have Fukuyama congenital muscular dystrophy (FCMD) on the basis of clinical findings. Epidemiologic data suggest that only 1/3,500 males with autosomal recessive FCMD should have abnormal dystrophin. To explain the observation of 3/23 FCMD males with abnormal dystrophin, the authors propose that dystrophin and the FCMD gene product interact and that the earlier onset and greater severity of these patients' phenotype (relative tomore » Duchenne muscular dystrophy) are due to their being heterozygous for the FCMD mutation in addition to being hemizygous for Duchenne muscular dystrophy, a genotype that is predicted to occur in 1/175,000 Japanese males. This model may help explain the genetic basis for some of the clinical and pathological variability seen among patients with FCMD, and it has potential implications for understanding the inheritance of other autosomal recessive disorders in general. For example, sex ratios for rare autosomal recessive disorders caused by mutations in proteins that interact with X chromosome-linked gene products may display predictable deviation from 1:1.« less

  12. Transmission of a t(13q22q) chromosome observed in three generations with segregation of the translocation D1-trisomy syndrome.

    PubMed

    Abe, T; Morita, M; Kawai, K; Misawa, S; Kanai, H; Hirose, G; Fujita, H

    1975-09-20

    A case of an inherited type of D/G translocation D1-trisomy syndrome was described. A female proposita who had the clinical signs of D1-trisomy syndrome was found to have a chromosome complement of 46,XX,--G,+t(DqGq). examination of Q- and G-stained karyotypes revealed that the chromosomes involved in the translocation were members of Nos. 13 and 22, or t(13q22q) with breaks at p12 of both chromosomes. C-stained figures also showed a large heterochromatin block in its centromeric region. The t(13q22q) chromosome was transmitted from the paternal grandmother of the proposita through at least three generations.

  13. MreB is important for cell shape but not for chromosome segregation of the filamentous cyanobacterium Anabaena sp. PCC 7120.

    PubMed

    Hu, Bin; Yang, Guohua; Zhao, Weixing; Zhang, Yingjiao; Zhao, Jindong

    2007-03-01

    MreB is a bacterial actin that plays important roles in determination of cell shape and chromosome partitioning in Escherichia coli and Caulobacter crescentus. In this study, the mreB from the filamentous cyanobacterium Anabaena sp. PCC 7120 was inactivated. Although the mreB null mutant showed a drastic change in cell shape, its growth rate, cell division and the filament length were unaltered. Thus, MreB in Anabaena maintains cell shape but is not required for chromosome partitioning. The wild type and the mutant had eight and 10 copies of chromosomes per cell respectively. We demonstrated that DNA content in two daughter cells after cell division in both strains was not always identical. The ratios of DNA content in two daughter cells had a Gaussian distribution with a standard deviation much larger than a value expected if the DNA content in two daughter cells were identical, suggesting that chromosome partitioning is a random process. The multiple copies of chromosomes in cyanobacteria are likely required for chromosome random partitioning in cell division.

  14. Enhanced conversion of induced neuronal cells (iN cells) from human fibroblasts: utility in uncovering cellular deficits in mental illness-associated chromosomal abnormalities

    PubMed Central

    Passeri, Eleonora; Wilson, Ashley M.; Primerano, Amedeo; Kondo, Mari A.; Sengupta, Srona; Srivastava, Rupali; Koga, Minori; Obie, Cassandra; Zandi, Peter P.; Goes, Fernando S.; Valle, David; Rapoport, Judith L.; Sawa, Akira; Kano, Shin-ichi; Ishizuka, Koko

    2016-01-01

    The novel technology of induced neuronal cells (iN cells) is promising for translational neuroscience, as it allows the conversion of human fibroblasts into cells with postmitotic neuronal traits. However, a major technical barrier is the low conversion rate. To overcome this problem, we optimized the conversion media. Using our improved formulation, we studied how major mental illness-associated chromosomal abnormalities may impact the characteristics of iN cells. We demonstrated that our new iN cell culture protocol enabled us to obtain more precise measurement of neuronal cellular phenotypes than previous iN cell methods. Thus, this iN cell culture provides a platform to efficiently obtain possible cellular phenotypes caused by genetic differences, which can be more thoroughly studied in research using other human cell models such as induced pluripotent stem cells. PMID:26260244

  15. Electrophoresis of phosphoglycerate kinase-2 to determine testicular damage induced by ethylene glycol monomethyl ether and sterility associated with chromosomal abnormality.

    PubMed

    Koizumi, A; Hamade, N; Arai, M; Takatoku, M; Yasuhiko, W; Tsukada, M; Kamiyama, S

    1990-01-01

    Phosphoglycerate kinase (PGK, EC 2.7.2.3), which is expressed specifically in sperm and spermatids, is an enzyme in the Embden-Meyerhof pathway that converts glucose to pyruvate. We developed an electrophoresis method to determine relative PGK-2 quantity and applied it to evaluate spermatogenesis activity. In the ethylene glycol monomethyl ether (EGME)-induced testicular toxicity, relative PGK-2 quantity had not decreased until 4 weeks of exposure. Mean relative PGK-2 quantities, defined as PGK-2 quantity over PGK-1 quantity in a pooled spleen sample (+/- SD) were: 1.43 +/- 0.32 for control animals (N = 10); 1.67 +/- 0.24 for the group exposed at 500 mg/kg for 5 days (N = 6); 1.85 +/- 0.58 for the group exposed at 500 mg/kg for 2 weeks (N = 6); 0.09 +/- 0.06 for the group exposed at 500 mg/kg for 4 weeks (N = 6); not detectable in animals exposed at 500 mg/kg for 5 weeks (N = 7); 0.208 +/- 0.103 for the group exposed at 250 mg/kg for 5 weeks (N = 6); and 1.35 +/- 0.38 for the group exposed at 125 mg/kg for 5 weeks (N = 6). These relative quantities showed a good correlation with sperm/spermatid counts (r = 0.823, p less than 0.01) and histological findings. These findings suggest that EGME has toxicity on primary spermatocytes and spermatogonia. In the case of sterility associated with a chromosomal abnormality (chromosomal translocation between chromosome X and 16), relative PGK-2 quantity was not detected in any of the seven adult (12 weeks of age) mice, although many primary spermatocytes were detected by histological examination.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Unique double de novo structural rearrangements for chromosome 11 with 46,XX,del(11)(q13q23)/46,XX,inv dup(11)(q13q23) in an infant with minor congenital abnormalities and delayed development

    SciTech Connect

    Tharapel, A.T.; Zhao, J.; Smith, M.E.

    1994-09-01

    Reported here is a patient with two most unusual structural rearrangements, both involving chromosome 11. The first cell line showed an interstitial deletion of a chromosome 11 with a 46,XX,del(11)(q13q23) chromosome complement. In the second cell line, one of the chromosome 11s had a duplication for the exact region, (11)(q13q23), that was deleted in the first cell line. This duplication also appeared to be inverted with karyotype 46,XX,inv dup(11)(q13q23). Interestingly, chromosome analysis did not reveal a normal cell line and the two abnormal cell lines were present in a 1:1 ratio. Parental chromosome analyses showed normal karyotypes. The patient wasmore » referred for genetic evaluation because of developmental delay. Minor congenital anomalies presented on physical examination included: weight and height at or below the 5th percentile, microcephaly, downward slanting palpebral fissures, severe clinodactyly of one toe, bilateral short fifth fingers and a broad based gait. Results of the MRI and urine metabolic screen were normal. Two hypotheses are advanced to explain the origin of the abnormality. It is most likely that the abnormality arose as a postzygotic event at the very early zygotic division. During the first DNA synthesis after fertilization and before the zygotic division, DNA synthesis errors could result in two chromatids, one with a deletion and the other with a duplication. It is also possible that after the DNA synthesis prior to the first cell division, the chromatids of the same chromosome 11 for unknown reasons were involved in uneven double somatic crossing over events resulting in deleted and duplicated chromatids, respectively. The 1:1 cell ratio found in the patient and the apparent non-existence of a normal cell line further suggest that the origin of the abnormality was post-zygotic.« less

  17. Chromosomal Abnormalities Are Major Prognostic Factors in Elderly Patients With Multiple Myeloma: The Intergroupe Francophone du Myélome Experience

    PubMed Central

    Avet-Loiseau, Hervé; Hulin, Cyrille; Campion, Loic; Rodon, Philippe; Marit, Gerald; Attal, Michel; Royer, Bruno; Dib, Mamoun; Voillat, Laurent; Bouscary, Didier; Caillot, Denis; Wetterwald, Marc; Pegourie, Brigitte; Lepeu, Gerard; Corront, Bernadette; Karlin, Lionel; Stoppa, Anne-Marie; Fuzibet, Jean-Gabriel; Delbrel, Xavier; Guilhot, Francois; Kolb, Brigitte; Decaux, Olivier; Lamy, Thierry; Garderet, Laurent; Allangba, Olivier; Lifermann, Francois; Anglaret, Bruno; Moreau, Philippe; Harousseau, Jean-Luc; Facon, Thierry

    2013-01-01

    Purpose Chromosomal abnormalities, especially t(4;14) and del(17p), are major prognostic factors in patients with multiple myeloma (MM). However, this has been especially demonstrated in patients age < 66 years treated with intensive approaches. The goal of this study was to address this issue in elderly patients treated with conventional-dose chemotherapy. Patients and Methods To answer this important question, we retrospectively analyzed a series of 1,890 patients (median age, 72 years; range, 66 to 94 years), including 1,095 with updated data on treatment modalities and survival. Results This large study first showed that the incidence of t(4;14) was not uniform over age, with a marked decrease in the oldest patients. Second, it showed that both t(4;14) and del(17p) retained their prognostic value in elderly patients treated with melphalan and prednisone–based chemotherapy. Conclusion t(4;14) and del(17p) are major prognostic factors in elderly patients with MM, both for progression-free and overall survival, indicating that these two abnormalities should be investigated at diagnosis of MM, regardless of age. PMID:23796999

  18. The Precarious Prokaryotic Chromosome

    PubMed Central

    2014-01-01

    Evolutionary selection for optimal genome preservation, replication, and expression should yield similar chromosome organizations in any type of cells. And yet, the chromosome organization is surprisingly different between eukaryotes and prokaryotes. The nuclear versus cytoplasmic accommodation of genetic material accounts for the distinct eukaryotic and prokaryotic modes of genome evolution, but it falls short of explaining the differences in the chromosome organization. I propose that the two distinct ways to organize chromosomes are driven by the differences between the global-consecutive chromosome cycle of eukaryotes and the local-concurrent chromosome cycle of prokaryotes. Specifically, progressive chromosome segregation in prokaryotes demands a single duplicon per chromosome, while other “precarious” features of the prokaryotic chromosomes can be viewed as compensations for this severe restriction. PMID:24633873

  19. Meiotic segregation analysis in spermatozoa of pericentric inversion carriers using fluorescence in-situ hybridization.

    PubMed

    Morel, F; Laudier, B; Guérif, F; Couet, M L; Royère, D; Roux, C; Bresson, J L; Amice, V; De Braekeleer, M; Douet-Guilbert, N

    2007-01-01

    Pericentric inversions are structural chromosomal abnormalities resulting from two breaks, one on either side of the centromere, within the same chromosome, followed by 180 degrees rotation and reunion of the inverted segment. They can perturb spermatogenesis and lead to the production of unbalanced gametes through the formation of an inversion loop. We report here the analysis of the meiotic segregation in spermatozoa from six pericentric inversion carriers by multicolour fluorescence in-situ hybridization (FISH) and review the literature. The frequencies of the non-recombinant products (inversion or normal chromosomes) were 80% for the inv(20), 91.41% for the inv(12), 99.43% for the inv(2), 68.12% for the inv(1), 97% for the inv(8)(p12q21) and 60.94% for the inv(8)(p12q24.1). The meiotic segregation of 20 pericentric inversions (including ours) is now available. The frequency of unbalanced spermatozoa varies from 0 to 37.85%. The probability of a crossover within the inverted segment is affected by the chromosome and region involved, the length of the inverted segment and the location of the breakpoints. No recombinant chromosomes were produced when the inverted segment involved <30% of the chromosome length (independent of the size of the inverted segment). Between 30 and 50%, few recombinant chromosomes were produced, inducing a slightly increased risk of aneusomy of recombination in the offspring. The risk of aneusomy became very important when the inverted segment was >50% of the chromosome length. Studies on spermatozoa from inversion carriers help in the comprehension of the mechanisms of meiotic segregation. They should be integrated in the genetic exploration of the infertile men to give them a personalized risk assessment of unbalanced spermatozoa.

  20. Childhood-onset schizophrenia case with 2.2 Mb deletion at chromosome 3p12.2-p12.1 and two large chromosomal abnormalities at 16q22.3-q24.3 and Xq23-q28.

    PubMed

    Rudd, Danielle; Axelsen, Michael; Epping, Eric A; Andreasen, Nancy; Wassink, Thomas

    2015-04-01

    Childhood-onset schizophrenia is rare, comprising 1% of known schizophrenia cases. Here, we report a patient with childhood-onset schizophrenia who has three large chromosomal abnormalities: an inherited 2.2 Mb deletion of chromosome 3p12.2-p12.1, a de novo 16.7 Mb duplication of 16q22.3-24.3, and a de novo 43 Mb deletion of Xq23-q28.

  1. Cytogenetic analysis of CpG-oligonucleotide DSP30 plus Interleukin-2-Stimulated canine B-Cell lymphoma cells reveals the loss of one X Chromosome as the sole abnormality.

    PubMed

    Reimann-Berg, N; Murua Escobar, H; Kiefer, Y; Mischke, R; Willenbrock, S; Eberle, N; Nolte, I; Bullerdiek, J

    2011-01-01

    Human and canine lymphoid neoplasms are characterized by non-random cytogenetic abnormalities. However, due to the low mitotic activity of the B cells, cytogenetic analyses of B-cell lymphoid proliferations are difficult to perform. In the present study we stimulated canine B-cell lymphoma cells with the immunostimulatory CpG-oligonucleotide DSP30 in combination with interleukin-2 (IL-2) and obtained an adequate number of metaphases. Cytogenetic analyses revealed the loss of one X chromosome as the sole cytogenetic aberration. Chromosome analysis of the corresponding blood showed a normal female karyotype. Monosomy X as the sole clonal chromosomal abnormality is found in human hematopoietic malignancies as well, thus the dog may serve as a promising animal model. Copyright © 2011 S. Karger AG, Basel.

  2. A Rare De novo Complex Chromosomal Rearrangement (CCR) Involving Four Chromosomes in An Oligo-asthenosperm Infertile Man

    PubMed Central

    Asia, Saba; Vaziri Nasab, Hamed; Sabbaghian, Marjan; Kalantari, Hamid; Zari Moradi, Shabnam; Gourabi, Hamid; Mohseni Meybodi, Anahita

    2014-01-01

    Complex chromosomal rearrangements (CCRs) are rare events involving more than two chromosomes and over two breakpoints. They are usually associated with infertility or sub fertility in male carriers. Here we report a novel case of a CCR in a 30-year-old oligoasthenosperm man with a history of varicocelectomy, normal testes size and normal endocrinology profile referred for chromosome analysis to the Genetics unit of Royan Reproductive Biomedicine Research Center. Chromosomal analysis was performed using peripheral blood lymphocyte cultures and analyzed by GTG banding. Additional tests such as C-banding and multicolor fluorescence in situ hybridization (FISH) procedure for each of the involved chromosomes were performed to determine the patterns of the segregations. Y chromosome microdeletions in the azoospermia factor (AZF) region were analyzed with multiplex polymerase chain reaction. To identify the history and origin of this CCR, all the family members were analyzed. No micro deletion in Y chromosome was detected. The same de novo reciprocal exchange was also found in his monozygous twin brother. The other siblings and parents were normal. CCRs are associated with male infertility as a result of spermatogenic disruption due to complex meiotic configurations and the production of chromosomally abnormal sperms. These chromosomal rearrangements might have an influence on decreasing the number of sperms. PMID:24611143

  3. Finding the middle ground: how kinetochores power chromosome congression

    PubMed Central

    Saurin, Adrian T.

    2010-01-01

    Genomic stability requires error-free chromosome segregation during mitosis. Chromosome congression to the spindle equator precedes chromosome segregation in anaphase and is a hallmark of metazoan mitosis. Here we review the current knowledge and concepts on the processes that underlie chromosome congression, including initial attachment to spindle microtubules, biorientation, and movements, from the perspective of the kinetochore. PMID:20232224

  4. A dynamic meiotic SUN belt includes the zygotene-stage telomere bouquet and is disrupted in chromosome segregation mutants of maize (Zea mays L.)

    PubMed Central

    Murphy, Shaun P.; Gumber, Hardeep K.; Mao, Yunyun; Bass, Hank W.

    2014-01-01

    The nuclear envelope (NE) plays an essential role in meiotic telomere behavior and links the cytoplasm and nucleoplasm during homologous chromosome pairing and recombination in many eukaryotic species. Resident NE proteins including SUN (Sad-1/UNC-84) and KASH (Klarsicht/ANC-1/Syne-homology) domain proteins are known to interact forming the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex that connects chromatin to the cytoskeleton. To investigate the possible cross-kingdom conservation of SUN protein functions in plant meiosis, we immunolocalized maize SUN2 using 3D microscopy of pollen mother cells from maize (Zea mays L.), a large-genome plant model with a canonical NE zygotene-stage telomere bouquet. We detected SUN2 at the nuclear periphery and found that it exhibited a distinct belt-like structure that transitioned to a half-belt during the zygotene stage and back to a full belt during and beyond the pachytene stage. The zygotene-stage half-belt SUN structure was shown by 3D immuno-FISH to include the NE-associated telomere cluster that defines the bouquet stage and coincides with homologous chromosome synapsis. Microtubule and filamentous actin staining patterns did not show any obvious belt or a retracted-like structure other than a general enrichment of tubulin staining distributed widely around the nucleus and throughout the cytoplasm. Genetic disruption of the meiotic SUN belt staining patterns with three different meiosis-specific mutants, desynaptic (dy1), asynaptic1 (as1), and divergent spindle1 (dv1) provides additional evidence for the role of the nuclear envelope in meiotic chromosome behavior. Taking into account all of the observations from this study, we propose that the maize SUN belt is directly or indirectly involved in meiotic telomere dynamics, chromosome synapsis, and possibly integration of signals and forces across the meiotic prophase nuclear envelope. PMID:25071797

  5. Loci on chromosomes 1A and 2A affect resistance to tan (yellow) spot in wheat populations not segregating for tsn1.

    PubMed

    Shankar, Manisha; Jorgensen, Dorthe; Taylor, Julian; Chalmers, Ken J; Fox, Rebecca; Hollaway, Grant J; Neate, Stephen M; McLean, Mark S; Vassos, Elysia; Golzar, Hossein; Loughman, Robert; Mather, Diane E

    2017-12-01

    QTL for tan spot resistance were mapped on wheat chromosomes 1A and 2A. Lines were developed with resistance alleles at these loci and at the tsn1 locus on chromosome 5B. These lines expressed significantly higher resistance than the parent with tsn1 only. Tan spot (syn. yellow spot and yellow leaf spot) caused by Pyrenophora tritici-repentis is an important foliar disease of wheat in Australia. Few resistance genes have been mapped in Australian germplasm and only one, known as tsn1 located on chromosome 5B, is known in Australian breeding programs. This gene confers insensitivity to the fungal effector ToxA. The main aim of this study was to map novel resistance loci in two populations: Calingiri/Wyalkatchem, which is fixed for the ToxA-insensitivity allele tsn1, and IGW2574/Annuello, which is fixed for the ToxA-sensitivity allele Tsn1. A second aim was to combine new loci with tsn1 to develop lines with improved resistance. Tan spot severity was evaluated at various growth stages and in multiple environments. Symptom severity traits exhibited quantitative variation. The most significant quantitative trait loci (QTL) were detected on chromosomes 2A and 1A. The QTL on 2A explained up to 29.2% of the genotypic variation in the Calingiri/Wyalkatchem population with the resistance allele contributed by Wyalkatchem. The QTL on 1A explained up to 28.1% of the genotypic variation in the IGW2574/Annuello population with the resistance allele contributed by Annuello. The resistance alleles at both QTL were successfully combined with tsn1 to develop lines that express significantly better resistance at both seedling and adult plant stages than Calingiri which has tsn1 only.

  6. Dementia revealed: novel chromosome 6 locus for late-onset Alzheimer disease provides genetic evidence for folate-pathway abnormalities.

    PubMed

    Naj, Adam C; Beecham, Gary W; Martin, Eden R; Gallins, Paul J; Powell, Eric H; Konidari, Ioanna; Whitehead, Patrice L; Cai, Guiqing; Haroutunian, Vahram; Scott, William K; Vance, Jeffery M; Slifer, Michael A; Gwirtsman, Harry E; Gilbert, John R; Haines, Jonathan L; Buxbaum, Joseph D; Pericak-Vance, Margaret A

    2010-09-23

    Genome-wide association studies (GWAS) of late-onset Alzheimer disease (LOAD) have consistently observed strong evidence of association with polymorphisms in APOE. However, until recently, variants at few other loci with statistically significant associations have replicated across studies. The present study combines data on 483,399 single nucleotide polymorphisms (SNPs) from a previously reported GWAS of 492 LOAD cases and 496 controls and from an independent set of 439 LOAD cases and 608 controls to strengthen power to identify novel genetic association signals. Associations exceeding the experiment-wide significance threshold (alpha=1.03x10(-7)) were replicated in an additional 1,338 cases and 2,003 controls. As expected, these analyses unequivocally confirmed APOE's risk effect (rs2075650, P=1.9x10(-36)). Additionally, the SNP rs11754661 at 151.2 Mb of chromosome 6q25.1 in the gene MTHFD1L (which encodes the methylenetetrahydrofolate dehydrogenase (NADP+ dependent) 1-like protein) was significantly associated with LOAD (P=4.70x10(-8); Bonferroni-corrected P=0.022). Subsequent genotyping of SNPs in high linkage disequilibrium (r2>0.8) with rs11754661 identified statistically significant associations in multiple SNPs (rs803424, P=0.016; rs2073067, P=0.03; rs2072064, P=0.035), reducing the likelihood of association due to genotyping error. In the replication case-control set, we observed an association of rs11754661 in the same direction as the previous association at P=0.002 (P=1.90x10(-10) in combined analysis of discovery and replication sets), with associations of similar statistical significance at several adjacent SNPs (rs17349743, P=0.005; rs803422, P=0.004). In summary, we observed and replicated a novel statistically significant association in MTHFD1L, a gene involved in the tetrahydrofolate synthesis pathway. This finding is noteworthy, as MTHFD1L may play a role in the generation of methionine from homocysteine and influence homocysteine

  7. Segregation of a paternal insertional translocation results in partial 4q monosomy or 4q trisomy in two siblings

    SciTech Connect

    Hegmann, K.M.; Spikes, A.S.; Orr-Urtreger, A.

    A genetics evaluation was requested for a 6-week-old infant with multiple congenital malformations including mild craniofacial anomalies, truncal hypotonia, hypospadias, and a ventriculoseptal defect. Blood obtained for chromosome analysis revealed an abnormal chromosome 4. Paternal chromosome analysis showed a 46,XY, inv ins (3;4)(p21.32;q25q21.2), inv(4)(p15.3q21.2) karyotype. Therefore, the proband`s chromosome 4 was the unbalanced product of this insertional translocation from the father resulting in partial monosomy 4q. Additionally, the derivative 4 had a pericentric inversion which was also seen in the father`s chromosome 4. During genetic counseling, the proband`s 2-year-old brother was evaluated. He was not felt to be abnormal inmore » appearance, but was described as having impulsive behavior. Chromosome analysis on this child revealed 46, XY, der(3) inv ins(3;4)(p21.32;q25q21.2)pat. This karyotype results in partial trisomy 4q. FISH using two-color {open_quotes}painting{close_quotes} probes for chromosomes 3 and 4 confirmed the G-banded interpretation in this family. The segregation seen in this family resulted in both reciprocal products being observed in the two children, with partial 4q monosomy showing multiple congenital anomalies, and partial 4q trisomy showing very few phenotypic abnormalities. 13 refs., 5 figs.« less

  8. From equator to pole: splitting chromosomes in mitosis and meiosis

    PubMed Central

    Duro, Eris

    2015-01-01

    During eukaryotic cell division, chromosomes must be precisely partitioned to daughter cells. This relies on a mechanism to move chromosomes in defined directions within the parental cell. While sister chromatids are segregated from one another in mitosis and meiosis II, specific adaptations enable the segregation of homologous chromosomes during meiosis I to reduce ploidy for gamete production. Many of the factors that drive these directed chromosome movements are known, and their molecular mechanism has started to be uncovered. Here we review the mechanisms of eukaryotic chromosome segregation, with a particular emphasis on the modifications that ensure the segregation of homologous chromosomes during meiosis I. PMID:25593304

  9. White matter microstructural abnormalities in girls with chromosome 22q11.2 deletion syndrome, Fragile X or Turner syndrome as evidenced by diffusion tensor imaging

    PubMed Central

    Villalon, Julio; Jahanshad, Neda; Beaton, Elliott; Toga, Arthur W.; Thompson, Paul M.; Simon, Tony J.

    2014-01-01

    Children with chromosome 22q11.2 Deletion Syndrome (22q11.2DS), Fragile X Syndrome (FXS), or Turner Syndrome (TS) are considered to belong to distinct genetic groups, as each disorder is caused by separate genetic alterations. Even so, they have similar cognitive and behavioral dysfunctions, particularly in visuospatial and numerical abilities. To assess evidence for common underlying neural microstructural alterations, we set out to determine whether these groups have partially overlapping white matter abnormalities, relative to typically developing controls. We scanned 101 female children between 7 and 14 years old: 25 with 22q11.2DS, 18 with FXS, 17 with TS, and 41 aged-matched controls using diffusion tensor imaging (DTI). Anisotropy and diffusivity measures were calculated and all brain scans were nonlinearly aligned to population and site-specific templates. We performed voxel-based statistical comparisons of the DTI-derived metrics between each disease group and the controls, while adjusting for age. Girls with 22q11.2DS showed lower fractional anisotropy (FA) than controls in the association fibers of the superior and inferior longitudinal fasciculi, the splenium of the corpus callosum, and the corticospinal tract. FA was abnormally lower in girls with FXS in the posterior limbs of the internal capsule, posterior thalami, and precentral gyrus. Girls with TS had lower FA in the inferior longitudinal fasciculus, right internal capsule and left cerebellar peduncle. Partially overlapping neurodevelopmental anomalies were detected in all three neurogenetic disorders. Altered white matter integrity in the superior and inferior longitudinal fasciculi and thalamic to frontal tracts may contribute to the behavioral characteristics of all of these disorders. PMID:23602925

  10. Individualized correction for maternal weight in calculating the risk of chromosomal abnormalities with first-trimester screening data.

    PubMed

    Merz, E; Thode, C; Eiben, B; Faber, R; Hackelöer, B J; Huesgen, G; Pruggmaier, M; Wellek, S

    2011-02-01

    In the algorithm developed by the Fetal Medicine Foundation (FMF) Germany designed to evaluate the findings of routine first-trimester screening, the false-positive rate (FPR) was determined for the entire study group without stratification by maternal weight. Based on the data received from the continuous audit we were able to identify an increase in the FPR for the weight-related subgroups of patients, particularly for patients with extremely high body weights. The aim of this study was to demonstrate that the variability of the FPR can be reduced through adjusting the concentrations of free β-HCG and PAPP-A measured in the maternal serum by means of a nonlinear regression function modeling the dependence of these values on maternal weight. The database used to establish a version of the algorithm enabling control of the FPR over the whole range of maternal weight consisted of n = 123 546 pregnancies resulting in the birth of a child without chromosomal anomalies. The group with positive outcomes covered n = 500 cases of trisomy 21 and n = 159 trisomies 13 or 18. The dependency of the serum parameters free β-HCG and PAPP-A on maternal weight was analyzed in the sample of negative outcomes by means of nonlinear regression. The fitted regression curve was of exponential form with negative slope. Using this model, all individual measurements were corrected through multiplication with a factor obtained as the ratio of the concentration level predicted by the model to belong to the average maternal body weight of 68.2 kg, over the ordinate of that point on the regression curve which belongs to the weight actually measured. Subsequently, the totality of all values of free β-HCG and PAPP-A corrected for deviation from average weight were used as input data for carrying out the construction of diagnostic discrimination rules described in our recent paper for a database to which no corrections for over- or under-weight had been applied. This entailed in particular the

  11. Parental decisions regarding prenatally detected fetal sex chromosomal abnormality and the impact of genetic counselling: an analysis of 57 cases in Taiwan.

    PubMed

    Shaw, Sheng-Wen; Chueh, Ho-Yen; Chang, Shuenn-Dyh; Cheng, Po-Jen; Hsieh, T'sang-T'ang; Soong, Yung-Kuei

    2008-04-01

    To analyse parental decisions regarding pregnancies with sex chromosome abnormalities (SCA). Collected and reviewed records from our hospital for 1991-2005. Genetic counselling was provided by obstetricians or perinatologists. Among 57 fetuses with SCA were 36 non-mosaic cases (four of 36, 45,X; 12 of 36, 47,XXY; seven of 36, 47,XYY, 13 of 36, 47,XXX) and 21 mosaic cases (15 of 21, 45,X mosaicism). Only 20% of 45,X mosaic pregnancies were continued, whereas all other mosaic pregnancies (100%) were continued (P = 0.004). Of 32 SCA cases counselled by a perinatologist, 66% (21 of 32) were continued. In contrast, 36% (nine of 25) of cases counselled by a general obstetrician were continued, a barely significant difference (P = 0.048). More couples chose to continue pregnancies in recent years. Genetic counselling by well-trained specialists is valuable, and the trend towards fewer terminations at our centre suggests improved parental knowledge of pathology associated with SCA.

  12. Assessment of Genotoxic Potential of Hridayarnava Rasa (A Herbo-Mineralo-Metallic Ayurvedic Formulation) Using Chromosomal Aberration and Sperm Abnormality Assays

    PubMed Central

    Jagtap, Chandrashekhar Y.; Chaudhari, Swapnil Y.; Thakkar, Jalaram H.; Galib, R.; Prajapati, P. K.

    2014-01-01

    Objectives: Herbo-mineral formulations are being successfully used in therapeutics since centuries. But recently, they came under the scanner for their metallic contents especially the presence of heavy metals. Hence it is the need of the hour to assess and establish the safety of these formulations through toxicity studies. In line with the various toxicity studies that are being carried out, Government of India expressed the need for conducting genotoxicity studies of different metal- or mineral-based drugs. Till date very few Ayurvedic herbo-mineral formulations have been studied for their genotoxic potential. The present study is aimed to evaluate the genotoxic potential of Hridayarnava Rasa. Materials and Methods: It was prepared as per classical guidelines and administered to Swiss albino mice for 14 consecutive days. Chromosomal aberration and sperm abnormality assay were done to evaluate the genotoxic potential of the test drugs. Cyclophosphamide (CP) was taken as positive group and results were compared. Results: All treated groups exhibited significant body weight gain in comparison to CP group. Results revealed no structural deformity in the above parameters in comparison to the CP-treated group. Conclusion: Reported data showed that both tested samples of Hridayarnava Rasa does not possess genotoxic potential under the experimental conditions and can be safely used. PMID:25948961

  13. Non-invasive prenatal testing for fetal chromosomal abnormalities by low-coverage whole-genome sequencing of maternal plasma DNA: review of 1982 consecutive cases in a single center.

    PubMed

    Lau, T K; Cheung, S W; Lo, P S S; Pursley, A N; Chan, M K; Jiang, F; Zhang, H; Wang, W; Jong, L F J; Yuen, O K C; Chan, H Y C; Chan, W S K; Choy, K W

    2014-03-01

    To review the performance of non-invasive prenatal testing (NIPT) by low-coverage whole-genome sequencing of maternal plasma DNA at a single center. The NIPT result and pregnancy outcome of 1982 consecutive cases were reviewed. NIPT was based on low coverage (0.1×) whole-genome sequencing of maternal plasma DNA. All subjects were contacted for pregnancy and fetal outcome. Of the 1982 NIPT tests, a repeat blood sample was required in 23 (1.16%). In one case, a conclusive report could not be issued, probably because of an abnormal vanished twin fetus. NIPT was positive for common trisomies in 29 cases (23 were trisomy 21, four were trisomy 18 and two were trisomy 13); all were confirmed by prenatal karyotyping (specificity=100%). In addition, 11 cases were positive for sex-chromosomal abnormalities (SCA), and nine cases were positive for other aneuploidies or deletion/duplication. Fourteen of these 20 subjects agreed to undergo further investigations, and the abnormality was found to be of fetal origin in seven, confined placental mosaicism (CPM) in four, of maternal origin in two and not confirmed in one. Overall, 85.7% of the NIPT-suspected SCA were of fetal origin, and 66.7% of the other abnormalities were caused by CPM. Two of the six cases suspected or confirmed to have CPM were complicated by early-onset growth restriction requiring delivery before 34 weeks. Fetal outcome of the NIPT-negative cases was ascertained in 1645 (85.15%). Three chromosomal abnormalities were not detected by NIPT, including one case each of a balanced translocation, unbalanced translocation and triploidy. There were no known false negatives involving the common trisomies (sensitivity=100%). Low-coverage whole-genome sequencing of maternal plasma DNA was highly accurate in detecting common trisomies. It also enabled the detection of other aneuploidies and structural chromosomal abnormalities with high positive predictive value. Copyright © 2013 ISUOG. Published by John Wiley & Sons

  14. Maternal Telomere Length and Risk of Down Syndrome: Epidemiological Impact of Smokeless Chewing Tobacco and Oral Contraceptive on Segregation of Chromosome 21.

    PubMed

    Ray, Anirban; Hong, Chang-Sook; Feingold, Eleanor; Ghosh, Papiya; Ghosh, Priyanka; Bhaumik, Pranami; Dey, Subratakumar; Ghosh, Sujay

    2016-01-01

    We have previously demonstrated a relationship between children born with Down syndrome and maternal telomere length. Similarly, exposure to tobacco and oral contraceptives has been explored in one of our earlier studies as a risk factor for Down syndrome. In the present study, we consider the interactions among these risk factors associated with Down syndrome in a population from Kolkata, India, using analyses stratified by maternal age. We estimated the telomere length of women with children with Down syndrome by restriction enzyme/Southern blot methods. Linear regression was employed to estimate telomere shortening as an indicator of the maternal age of conception. Interactions among the various factors were analyzed by logistic regression. We found an association between the use of smokeless chewing tobacco and shorter telomere length among women who experienced meiosis I nondisjunction at gametogenesis; the effect is seen across all maternal age groups. In contrast, oral contraceptive use alone did not exhibit a statistically significant association with maternal telomere length, but there was an interaction with the use of smokeless chewing tobacco in the older mothers who experienced meiotic II nondisjunction. Environmental/habitual factors interact with molecular components of the oocyte, which ultimately increases the risk of chromosome 21 nondisjunction and subsequently of giving birth to a child with Down syndrome. © 2015 S. Karger AG, Basel.

  15. Hip3 interacts with the HIRA proteins Hip1 and Slm9 and is required for transcriptional silencing and accurate chromosome segregation.

    PubMed

    Greenall, Amanda; Williams, Emma S; Martin, Katherine A; Palmer, Jeremy M; Gray, Joe; Liu, Cong; Whitehall, Simon K

    2006-03-31

    The fission yeast HIRA proteins Hip1 and Slm9 are members of an evolutionarily conserved family of histone chaperones that are implicated in nucleosome assembly. Here we have used single-step affinity purification and mass spectrometry to identify factors that interact with both Hip1 and Slm9. This analysis identified Hip3, a previously uncharacterized 187-kDa protein, with similarity to S. cerevisiae Hir3. Consistent with this, cells disrupted for hip3+ exhibit a range of growth defects that are similar to those associated with loss of Hip1 and Slm9. These include temperature sensitivity, a cell cycle delay, and synthetic lethality with cdc25-22. Furthermore, genetic analysis also indicates that disruption of hip3+ is epistatic with mutation of hip1+ and slm9+. Mutation of hip3+ alleviates transcriptional silencing at several heterochromatic loci, including in the outer (otr) centromeric repeats, indicating that Hip3 is required for the integrity of pericentric heterochromatin. As a result, loss of Hip3 function leads to high levels of minichromosome loss and an increased frequency of lagging chromosomes during mitosis. Importantly, the function of Hip1, Slm9, and Hip3 is not restricted to constitutive heterochromatic loci, since these proteins also repress the expression of a number of genes, including the Tf2 retrotransposons.

  16. Women's access to abortion after 20 weeks' gestation for fetal chromosomal abnormalities: Views and experiences of doctors in New South Wales and Queensland.

    PubMed

    Black, Kirsten I; Douglas, Heather; de Costa, Caroline

    2015-04-01

    Induced abortions after 20 weeks' gestation comprise around one per cent of all terminations in Australia and mostly occur following the diagnosis of a fetal anomaly. However, these abortions are overly represented in legal cases against doctors and challenging to organise in those states where abortion remains in the criminal code and health department directives impose regulations. This study explores barriers to abortion access after 20 weeks' gestation in the states of Queensland and New South Wales. We approached and sought consent from 22 doctors involved in abortion provision (15 in Queensland and seven in NSW), who responded in depth to a set of clinical scenarios. This study presents participants' responses to three clinical scenarios of women presenting with a fetal chromosomal abnormality after 20 weeks' gestation. Of the 22 medical practitioners in this study, 18 reported that access to late-term abortion in their state was restricted. The two key factors perceived to affect the decision to terminate a pregnancy in this context were the legal status of abortion and Department of Health policies mandating that applications for abortion be presented to clinical ethics committees. Practitioners reported that committees were slow to convene and inconsistent in their decisions. Ethics committee involvement for late-term abortions is required by state health policy in NSW and Queensland, where abortion is still a criminal offence. This process is seen by abortion providers to hinder timely access to services and excludes women from the decision-making process. © 2015 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.

  17. CHROMOSOMAL ABNORMALITIES AMONG WELDER TRAINEES

    EPA Science Inventory

    Serial cytogenetic observations were made on a group of 273 military recruits who were being trained as welders at Aberdeen, Maryland. The trainees were being exposed to presumably increased levels of ozone in the course of their welding school experience, and it was the purpose ...

  18. Micromechanics of human mitotic chromosomes

    NASA Astrophysics Data System (ADS)

    Sun, Mingxuan; Kawamura, Ryo; Marko, John F.

    2011-02-01

    Eukaryote cells dramatically reorganize their long chromosomal DNAs to facilitate their physical segregation during mitosis. The internal organization of folded mitotic chromosomes remains a basic mystery of cell biology; its understanding would likely shed light on how chromosomes are separated from one another as well as into chromosome structure between cell divisions. We report biophysical experiments on single mitotic chromosomes from human cells, where we combine micromanipulation, nano-Newton-scale force measurement and biochemical treatments to study chromosome connectivity and topology. Results are in accord with previous experiments on amphibian chromosomes and support the 'chromatin network' model of mitotic chromosome structure. Prospects for studies of chromosome-organizing proteins using siRNA expression knockdowns, as well as for differential studies of chromosomes with and without mutations associated with genetic diseases, are also discussed.

  19. Lack of segregation of a Marfan-like phenotype associating marfanoie habitus and mitral valve disease with fibrillin gene on chromosome 15

    SciTech Connect

    VanMaldergen, L.; Hilbert, P.; Gillerot, Y.

    1994-09-01

    Apart from typical Marfan syndrome (MS), several Marfan-like conditions are known. One of those is the MASS syndrome (Mitral involvement, Aortic dilatation, Skin and Skeletal abnormalities) defined by Pyeritz et al. Among these, a dominantly inherited mitral valve prolapse with marfanoid habitus have also been reported. Until now, except for a Marfan-like condition described by Boileau et al., all Marfan families are linked to fib 15. A large Belgian pedigree with 25 affected patients among 62 at risk subjects spanning four generations is described. A syndrome including marfanoid skeletal dysplasia (tall stature, dolichostenomelia, arachnodactyly, pectus carinatum joint dislocation), prolapse and/ormore » myxomatous degeneration of the mitral valve, but without aortic dilatation of eye involvement was observed. Although the phenotype fulfills Berlin diagnostic criteria for MS, it closely resembles MASS syndrome. Preliminary linkage results show discordance aggregation insertion in the fib 15 gene, as evaluated by intragenic microsatellite fib 15. Since Dietz et al. described a similar patient with fib 15 gene, we suggest that this variant of Marfan syndrome is genetically heterogeneous and caused by mutations, some of which are allelic to classical Marfan syndrome plus a subtype, some of which are not. Linkage studies are under way to further characterize the gene involved in the present family.« less

  20. Childhood-onset schizophrenia case with 2.2 Mb deletion at chromosome 3p12.2–p12.1 and two large chromosomal abnormalities at 16q22.3–q24.3 and Xq23–q28

    PubMed Central

    Rudd, Danielle; Axelsen, Michael; Epping, Eric A; Andreasen, Nancy; Wassink, Thomas

    2015-01-01

    Key Clinical Message Childhood-onset schizophrenia is rare, comprising 1% of known schizophrenia cases. Here, we report a patient with childhood-onset schizophrenia who has three large chromosomal abnormalities: an inherited 2.2 Mb deletion of chromosome 3p12.2–p12.1, a de novo 16.7 Mb duplication of 16q22.3–24.3, and a de novo 43 Mb deletion of Xq23–q28. PMID:25914809

  1. Fluorescent in situ hybridization (FISH) assessment of chromosome copy number in sperm

    SciTech Connect

    Sheu, M.; Sigman, M.; Mark, H.F.L.

    Approximately 15% of all recognized pregnancies end in spontaneous abortions. The overall frequency of chromosome abnormalities in spontaneous abortions is approximately 50%. Thus aneuploidy is a significant cause of fetal wastage. In addition, structural and numerical abnormalities of chromosomes can also lead to birth defects, developmental delay, mental retardation and infertility. Conventional cytogenetic analysis via GTG- and other banding techniques is a powerful tool in the elucidation of the nature of chromosomal abnormalities. Fluorescent in situ hybridization (FISH) enables detection of numerical chromosomal abnormalities, especially trisomies, in intact cells. Using FISH and commercially available biotin-labeled probes, we have initiated amore » prospective study to assess specific chromosome copy number of preparations of unstained smears from men referred for a male infertility evaluation as well as smears from normal control males chosen randomly from the sample of sperm donors. A total of approximately 19,000 sperm nuclei have been examined thus far. Of those suitable for analysis, 7382 (38.75%) were normal possessing one copy of chromosome 8, 155 (0.81%) were disomic, and 15 (0.079%) had more than two copies of chromosome 8. Comparisons with data available in the literature will be discussed. Work is ongoing to increase the efficiency of hybridization using both reported and previously untried pretreatment and fixation protocols. We have also initiated studies using multicolor FISH with various chromosome enumeration probes. The assay described here is a potentially powerful tool for detecting rare events such as spontaneous germ cell aneuploidy, aneuploidy detected in semen from men with carcinoma in situ of the testis and aneuploidy induced by potential environmental genotoxicants. It can also be utilized for segregation analysis and for correlating chromosome copy number with germ cell morphology.« less

  2. Image segregation in strabismic amblyopia.

    PubMed

    Levi, Dennis M

    2007-06-01

    Humans with naturally occurring amblyopia show deficits thought to involve mechanisms downstream of V1. These include excessive crowding, abnormal global image processing, spatial sampling and symmetry detection and undercounting. Several recent studies suggest that humans with naturally occurring amblyopia show deficits in global image segregation. The current experiments were designed to study figure-ground segregation in amblyopic observers with documented deficits in crowding, symmetry detection, spatial sampling and counting, using similar stimuli. Observers had to discriminate the orientation of a figure (an "E"-like pattern made up of 17 horizontal Gabor patches), embedded in a 7x7 array of Gabor patches. When the 32 "background" patches are vertical, the "E" pops-out, due to segregation by orientation and performance is perfect; however, if the background patches are all, or mostly horizontal, the "E" is camouflaged, and performance is random. Using a method of constant stimuli, we varied the number of "background" patches that were vertical and measured the probability of correct discrimination of the global orientation of the E (up/down/left/right). Surprisingly, amblyopes who showed strong crowding and deficits in symmetry detection and counting, perform normally or very nearly so in this segregation task. I therefore conclude that these deficits are not a consequence of abnormal segregation of figure from background.

  3. Chromosome 13q deletion and IgH abnormalities may be both masked by near-tetraploidy in a high proportion of multiple myeloma patients: a combined morphology and I-FISH analysis.

    PubMed

    Koren-Michowitz, Maya; Hardan, Izhar; Berghoff, Janina; Yshoev, Galina; Amariglio, Ninette; Rechavi, Gideon; Nagler, Arnon; Trakhtenbrot, Luba

    2007-10-08

    Ploidy status and chromosomal aberrations involving chromosome 13q and the immunoglobulin heavy chain locus (IgH) are important prognostic features in multiple myeloma (MM). However, conventional cytogenetic studies are often not reveling and determination of plasma cells (PC) ploidy status in MM is technically difficult. We have used a combined cell morphology and interphase FISH (I-FISH) analysis in 184 consecutive BM samples from 136 MM patients for the diagnosis of chromosome 13q deletion [del (13q)] and IgH abnormalities. We have found a high prevalence (37%) of near-tetraploid (NT) PC in the BM samples studied. NT status of PC was verified with DNA index (DI) measurements. del (13q) was found in 69% and a total absence of one IgH copy (loss of IgH) in 20% of NT samples. We have shown that the presence of del (13q) and loss of IgH can be masked in NT cases: in 12 NT samples originally identified as normal for del (13q) the abnormality was obscured in the majority of plasma cells due to the presence of NT. Similarly, loss of IgH was masked in four samples with a large population of NT cells. Moreover, in one case the appearance of a 100% tetraploidy during disease progression masked the presence of del (13q), originally present, and could therefore falsely appear as disappearance of this prognostic marker. In conclusion, we have shown that a combination of three abnormalities, i.e., del (13q), loss of IgH and NT, all of potential prognostic significance, can be overlooked unless NT is specifically searched for and ruled out. Therefore, we suggest that a search for NT should be added to the routine BM assessment in MM patients.

  4. Aneuploidy in immortalized human mesenchymal stem cells with non-random loss of chromosome 13 in culture.

    PubMed

    Takeuchi, Masao; Takeuchi, Kikuko; Ozawa, Yutaka; Kohara, Akihiro; Mizusawa, Hiroshi

    2009-01-01

    Aneuploidy (an abnormal number of chromosomes) is commonly observed in most human cancer cells, highlighting the need to examine chromosomal instability in tumorigenesis. Previously, the immortalized human mesenchymal stem cell line UE6E7T-3 was shown to undergo a preferential loss of one copy of chromosome 13 after prolonged culture. Here, the loss of chromosome 13 was found to be caused by chromosome missegregation during mitosis, which involved unequal segregation, exclusion of the misaligned chromosome 13 on the metaphase plate, and trapping of chromosome 13 in the midbody region, as observed by fluorescence in situ hybridization. Near-diploid aneuploidy, not tetraploidy, was the direct result. The loss of chromosome 13 was non-random, and was detected by analysis of microsatellites and single nucleotide polymorphism-based loss of heterozygosity (LOH). Of the five microsatellite loci on chromosome 13, four loci showed microsatellite instability at an early stage in culture, and LOH was apparent at a late stage in culture. These results suggest that the microsatellite mutations cause changes in centromere integrity provoking loss of this chromosome in the UE6E7T-3 cell line. Thus, these results support the use of this cell line as a useful model for understanding the mechanism of aneuploid formation in cell cultures.

  5. Abnormal protein in the cerebrospinal fluid of patients with a submicroscopic X-chromosomal deletion associated with Norrie disease: preliminary report.

    PubMed

    Joy, J E; Poglod, R; Murphy, D L; Sims, K B; de la Chapelle, A; Sankila, E M; Norio, R; Merril, C R

    1991-01-01

    Norrie disease is an X-linked recessive disorder characterized by congenital blindness and, in many cases, mental retardation. Some Norrie disease cases have been shown to be associated with a submicroscopic deletion in chromosomal region Xp11.3. Cerebrospinal fluid (CSF) was collected from four male patients with an X-chromosomal deletion associated with Norrie disease. CSF proteins were resolved using two-dimensional gel electrophoresis and then analyzed by computer using the Elsie V program. Our analysis revealed a protein that appears to be altered in patients with Norrie disease deletion.

  6. Centrosome Linker-induced Tetraploid Segregation Errors Link Rhabdoid Phenotypes and Lethal Colorectal Cancers.

    PubMed

    Remo, Andrea; Manfrin, Erminia; Parcesepe, Pietro; Ferrarini, Alberto; Han, Hye Seung; Ugnius, Mickys; Laudanna, Carmelo; Simbolo, Michele; Malanga, Donatella; Mendes Oliveira, Duarte; Baritono, Elisabetta; Colangelo, Tommaso; Sabatino, Lina; Giuliani, Jacopo; Molinari, Enrico; Garonzi, Marianna; Xumerle, Luciano; Delledonne, Massimo; Giordano, Guido; Ghimenton, Claudio; Lonardo, Fortunato; D'angelo, Fulvio; Grillo, Federica; Mastracci, Luca; Viglietto, Giuseppe; Ceccarelli, Michele; Colantuoni, Vittorio; Scarpa, Aldo; Pancione, Massimo

    2018-05-21

    Centrosome anomalies contribute to tumorigenesis but it remains unclear how they are generated in lethal cancer phenotypes. Here, it is demonstrated that human microsatellite instable (MSI) and BRAF(V600E) mutant colorectal cancers with a lethal rhabdoid phenotype are characterized by inactivation of centrosomal functions. A splice site mutation that causes an unbalanced dosage of rootletin (CROCC), a centrosomal-linker component required for centrosome cohesion and separation at the chromosome 1p36.13 locus, resulted in abnormally shaped centrosomes in rhabdoid cells from human colon tissues. Notably, deleterious deletions at 1p36.13 were recurrent in a subgroup of BRAF(V600E) mutant and microsatellite stable (MSS) rhabdoid colorectal cancers but not in classical colorectal cancer or pediatric rhabdoid tumors. Interfering with CROCC expression in near-diploid BRAF(V600E) mutant/MSI colon cancer cells disrupts bipolar mitotic spindle architecture, promotes tetraploid segregation errors resulting in a highly aggressive rhabdoid-like phenotype in vitro. Restoring near-wild-type levels of CROCC in a metastatic model harboring 1p36.13 deletion results in correction of centrosome segregation errors and cell death, revealing a mechanism of tolerance to mitotic errors and tetraploidization promoted by deleterious 1p36.13 loss. Accordingly, cancer cells lacking 1p36.13 display far greater sensitivity to centrosome spindle pole stabilizing agents in vitro. These data shed light on a previously unknown link between centrosome cohesion defects and lethal cancer phenotypes providing new insight into pathways underlying genome instability. Mis-segregation of chromosomes is a prominent feature of chromosome instability and intra-tumoral heterogeneity recurrent in metastatic tumors for which the molecular basis is unknown. The present study provides insight into the mechanism by which defects in rootletin, a centrosome linker component causes tetraploid segregation errors and

  7. Cytogenetic Analysis of Segregation Distortion in Drosophila Melanogaster: The Cytological Organization of the Responder (Rsp) Locus

    PubMed Central

    Pimpinelli, S.; Dimitri, P.

    1989-01-01

    The segregation distortion phenomenon occurs in Drosophila melanogaster males carrying an SD second chromosome and an SD(+) homolog. In such males the SD chromosome is transmitted to the progeny more frequently than the expected 50% because of an abnormal differentiation of the SD(+)-bearing sperms. Three major loci are involved in this phenomenon: SD and Rsp, associated with the SD and SD(+) chromosome, respectively, and E(SD). In the present work we performed a cytogenetic analysis of the Rsp locus which was known to map to the centromeric heterochromatin of the second chromosome. Hoechst- and N-banding techniques were used to characterize chromosomes carrying Responder insensitive (Rsp(i)), Responder sensitive (Rsp(s)) and Responder supersensitive (Rsp(ss)) alleles. Our results locate the Rsp locus to the h39 region of 2R heterochromatin. This region is a Hoechstbright, N-banding negative heterochromatic block adjacent to the centromere. Quantitative variations of the h39 region were observed. The degree of sensitivity to Sd was found to be directly correlated with the physical size of that region, demonstrating that the Rsp locus is composed of repeated DNA. PMID:2470640

  8. [Hebephrenic symptoms as an expression of an XYY chromosome abnormality? Case report of a patient with suspected sexual abuse of his own 2 minor children].

    PubMed

    Dirksen, T; Mönikes, E

    1995-06-01

    A 48 year old patient was hospitalised because of parasuicidal behaviour and suicidal ideation. He was under suspicion of having sexually abused his 4-year old daughter and his 4-year old son. At the age of 17, he was hospitalised in a psychiatric ward under the diagnosis of hebephrenic schizophrenia. He successfully received an insulin coma therapy. Because of his increased height (1.89 m), mental retardation and other psychical disorders in his youth, we now suspected him of having an extra Y chromosome which was confirmed by chromosome analysis. The non-uniform symptomatology of XYY-individuals includes a hebephrenic aspect. Concerning the different therapeutical and juridical consequences, we considered a critical investigation of the former diagnosis "Hebephrenic Schizophrenia".

  9. Frequency and prognostic significance of additional cytogenetic abnormalities to the Philadelphia chromosome in young and older adults with acute lymphoblastic leukemia.

    PubMed

    Motlló, Cristina; Ribera, Josep-Maria; Morgades, Mireia; Granada, Isabel; Montesinos, Pau; Mercadal, Santiago; González-Campos, José; Moreno, María-José; Barba, Pere; Cervera, Marta; Barrios, Manuel; Novo, Andrés; Bernal, Teresa; Hernández-Rivas, Jesús-María; Abella, Eugenia; Amigo, María-Luz; Tormo, Mar; Martino, Rodrigo; Lavilla, Esperanza; Bergua, Juan; Serrano, Alfons; García-Belmonte, Daniel; Guàrdia, Ramon; Grau, Javier; Feliu, Evarist

    2018-01-01

    About 25-35% of adult patients with acute lymphoblastic leukemia show the Philadelphia (Ph) chromosome. Few series have evaluated the prognosis of additional cytogenetic alterations (ACA) to the Ph chromosome. We analyzed the frequency, type and prognostic significance ofACA in adults (18-60 years) treated in the ALL-Ph-08 trial. Fifty-two out of 74 patients (70%) showed ACA and 19 (26%) presented monosomies associated with t(9;22) (monosomal karyotype, MK). Similar complete response (CR) rate, CR duration, overall survival and event-free survival (EFS) were observed in patients with or without ACA, but patients with MK showed shorter CR duration and EFS than the remaining. On multivariate analysis, the only variable with prognostic impact for CR duration and EFS was the presence of MK (p = .003 and p = .036, respectively). Although ACA associated with the Ph chromosome are frequent, only monosomies were associated with poor prognosis in this group of patients.

  10. Overcoming Triple Segregation

    ERIC Educational Resources Information Center

    Gandara, Patricia

    2010-01-01

    Latinos are, after whites, the most segregated student group in the United States, and their segregation is closely tied to poor academic outcomes. Latinos experience a triple segregation: by race/ethnicity, poverty, and language. Racial segregation perpetuates negative stereotypes, reduces the likelihood of a strong teaching staff, and is often…

  11. The New Segregation.

    ERIC Educational Resources Information Center

    Laosa, Luis M.

    2001-01-01

    This issue reviews national demographic trends in school segregation, summarizing research findings. Though the national debate on school segregation emphasizes blacks and whites, present-day school segregation includes segregation by socioeconomic level, ethnicity, and native language. The research study examined features of the ecology of…

  12. Application of the FICTION technique for the simultaneous detection of immunophenotype and chromosomal abnormalities in routinely fixed, paraffin wax embedded bone marrow trephines

    PubMed Central

    Korać, P; Jones, M; Dominis, M; Kušec, R; Mason, D Y; Banham, A H; Ventura, R A

    2005-01-01

    The use of interphase fluorescence in situ hybridisation (FISH) to study cytogenetic abnormalities in routinely fixed paraffin wax embedded tissue has become commonplace over the past decade. However, very few studies have applied FISH to routinely fixed bone marrow trephines (BMTs). This may be because of the acid based decalcification methods that are commonly used during the processing of BMTs, which may adversely affect the suitability of the sample for FISH analysis. For the first time, this report describes the simultaneous application of FISH and immunofluorescent staining (the FICTION technique) to formalin fixed, EDTA decalcified and paraffin wax embedded BMTs. This technique allows the direct correlation of genetic abnormalities to immunophenotype, and therefore will be particularly useful for the identification of genetic abnormalities in specific tumour cells present in BMTs. The application of this to routine clinical practice will assist diagnosis and the detection of minimal residual disease. PMID:16311361

  13. Incidence, characterization and prognostic significance of chromosomal abnormalities in 640 patients with primary myelodysplastic syndromes. Grupo Cooperativo Español de Citogenética Hematológica.

    PubMed

    Solé, F; Espinet, B; Sanz, G F; Cervera, J; Calasanz, M J; Luño, E; Prieto, F; Granada, I; Hernández, J M; Cigudosa, J C; Diez, J L; Bureo, E; Marqués, M L; Arranz, E; Ríos, R; Martínez Climent, J A; Vallespí, T; Florensa, L; Woessner, S

    2000-02-01

    Recently, a consensus International Prognostic Scoring System (IPSS) for predicting outcome and planning therapy in the myelodysplastic syndromes (MDS) has been developed. However, the intermediate-risk cytogenetic subgroup defined by the IPSS includes a miscellaneous number of different single abnormalities for which real prognosis at present is uncertain. The main aims of this study were to evaluate in an independent series the prognostic value of the IPSS and to identify chromosomal abnormalities with a previously unrecognized good or poor prognosis in 640 patients. In univariate analyses, cases with single 1q abnormalities experienced poor survival, whereas those with trisomy 8 had a higher risk of acute leukaemic transformation than the remaining patients (P = 0.004 and P = 0.009 respectively). Patients with single del(12p) had a similar survival to patients with a normal karyotype and showed some trend for a better survival than other cases belonging to the IPSS intermediate-risk cytogenetic subgroup (P = 0.045). Multivariate analyses demonstrated that IPSS cytogenetic prognostic subgroup, proportion of bone marrow blasts and haemoglobin level were the main prognostic factors for survival, and the first two characteristics and platelet count were the best predictors of acute leukaemic transformation risk. A large international co-operative study should be carried out to clarify these findings.

  14. Excessive homozygosity identified by chromosomal microarray at a known GCDH mutation locus correlates with brain MRI abnormalities in an infant with glutaric aciduria.

    PubMed

    Peer-Zada, Abdul Ali; Al-Asmari, Ali M

    2017-08-01

    Herein, we report a conceptually novel clinical case highlighting the diagnostic implications of excessive homozygosity and its correlation with brain MRI abnormalities in an infant with GA1. The case also points a need for an extra amount of caution to be exercised when evaluating patients with "negative exomes."

  15. Detection of amplified or deleted chromosomal regions

    DOEpatents

    Stokke, Trond; Pinkel, Daniel; Gray, Joe W.

    1995-01-01

    The present invention relates to in situ hybridization methods for the identification of new chromosomal abnormalities associated with various diseases. In particular, it provides probes which are specific to a region of amplification in chromosome 20.

  16. Detection Of Amplified Or Deleted Chromosomal Regions

    DOEpatents

    Stokke, Trond , Pinkel, Daniel , Gray, Joe W.

    1997-05-27

    The present invention relates to in situ hybridization methods for the identification of new chromosomal abnormalities associated with various diseases. In particular, it provides probes which are specific to a region of amplification in chromosome 20.

  17. Detection of amplified or deleted chromosomal regions

    DOEpatents

    Stokke, T.; Pinkel, D.; Gray, J.W.

    1995-12-05

    The present invention relates to in situ hybridization methods for the identification of new chromosomal abnormalities associated with various diseases. In particular, it provides probes which are specific to a region of amplification in chromosome 20. 3 figs.

  18. Human gastrin-releasing peptide gene is located on chromosome 18.

    PubMed

    Naylor, S L; Sakaguchi, A Y; Spindel, E; Chin, W W

    1987-01-01

    Gastrin-releasing peptide (GRP), a bombesin-like peptide, increases plasma levels of gastrin, pancreatic polypeptide, glucagon, gastric inhibitory peptide, and insulin. GRP is produced in large quantities by small-cell lung cancer and acts as a growth factor for these cells. To determine if chromosomal changes in small-cell lung cancer are related to the expression of GRP, we chromosomally mapped the gene using human-mouse somatic cell hybrids. Twenty hybrids, characterized for human chromosomes, were analyzed by Southern filter hybridization of DNA digested with EcoRI. Human DNA cut with EcoRI yields a major band of 6.8 kb and a minor band of 11.3 kb. The 6.8 kb band segregated concordantly with chromosome 18 and the marker peptidase A. The chromosome 3 abnormalities seen in small-cell lung cancer do not correlate with the chromosomal location of GRP, suggesting that the elevated expression of this gene may be due to mechanisms other than chromosomal rearrangement.

  19. Pericentric inversion of chromosome 11 (p14.3q21) associated with developmental delays, hypopigmented skin lesions and abnormal brain MRI findings - a new case report

    SciTech Connect

    Zachor, D.A.; Lofton, M.

    1994-09-01

    We report 3 year old male, referred for evaluation of developmental delays. Pregnancy was complicated by oligohydramnios, proteinuria and prematurity. Medical history revealed: bilateral inguinal hernia, small scrotal sac, undescended testes, developmental delays and behavioral problems. The child had: microcephaly, facial dysmorphic features, single palmar creases, hypopigmented skin lesions of variable size, intermittent exotropia and small retracted testes. Neurological examination was normal. Cognitive level was at the average range with mild delay in his adaptive behavior. Expressive language delays and severe articulation disorder were noted, as well as clumsiness, poor control and precision of gross and fine motor skills. Chromosomalmore » analysis of peripheral leukocytes indicated that one of the number 11 chromosomes had undergone a pericentric inversion with breakpoints on the short (p) arm at band p14.3 and the long (q) arm at band q21. An MRI of the brain showed mild delay in myelinization pattern of white matter. Chromosome 11 inversion in other sites was associated with Beckwith-Wiedemann syndrome and several malignancies. To our knowledge this is the first description of inv(11)(p14.3q21) that is associated with microcephaly, dysmorphic features, hypopigmented skin lesions and speech delay. This inversion may disrupt the expression of the involved genes. However, additional cases with the same cytogenetic anomaly are needed to explore the phenotypic significance of this disorder.« less

  20. Chromosomal instability drives metastasis through a cytosolic DNA response.

    PubMed

    Bakhoum, Samuel F; Ngo, Bryan; Laughney, Ashley M; Cavallo, Julie-Ann; Murphy, Charles J; Ly, Peter; Shah, Pragya; Sriram, Roshan K; Watkins, Thomas B K; Taunk, Neil K; Duran, Mercedes; Pauli, Chantal; Shaw, Christine; Chadalavada, Kalyani; Rajasekhar, Vinagolu K; Genovese, Giulio; Venkatesan, Subramanian; Birkbak, Nicolai J; McGranahan, Nicholas; Lundquist, Mark; LaPlant, Quincey; Healey, John H; Elemento, Olivier; Chung, Christine H; Lee, Nancy Y; Imielenski, Marcin; Nanjangud, Gouri; Pe'er, Dana; Cleveland, Don W; Powell, Simon N; Lammerding, Jan; Swanton, Charles; Cantley, Lewis C

    2018-01-25

    Chromosomal instability is a hallmark of cancer that results from ongoing errors in chromosome segregation during mitosis. Although chromosomal instability is a major driver of tumour evolution, its role in metastasis has not been established. Here we show that chromosomal instability promotes metastasis by sustaining a tumour cell-autonomous response to cytosolic DNA. Errors in chromosome segregation create a preponderance of micronuclei whose rupture spills genomic DNA into the cytosol. This leads to the activation of the cGAS-STING (cyclic GMP-AMP synthase-stimulator of interferon genes) cytosolic DNA-sensing pathway and downstream noncanonical NF-κB signalling. Genetic suppression of chromosomal instability markedly delays metastasis even in highly aneuploid tumour models, whereas continuous chromosome segregation errors promote cellular invasion and metastasis in a STING-dependent manner. By subverting lethal epithelial responses to cytosolic DNA, chromosomally unstable tumour cells co-opt chronic activation of innate immune pathways to spread to distant organs.

  1. [Chromosome examination of missed abortion patients].

    PubMed

    Hu, Haomei; Yang, Hua; Yin, Zhenhui; Zhao, Lu

    2015-09-15

    To investigate the relationship between the missed abortion and chromosome abnormality and guide the healthy birth. From June 2014 to April 2015 in Tianjin central hospital of gynecology and obstetrics, we examined venous blood from 90 missed abortion couples for chromosome karyotype by lymphocyte culture method and we also examined their chromosome karyotype of abortion villus samples by high-throughput sequencing technologies. Out of the 90 couples' blood chromosome examinations, 7 were abnormal, and the abnormal rate was 3.89%, including 3 cases reciprocal translocation, 2 cases robertsonian translocation and 2 cases inversion. Abortion villus samples from the same population were also checked, of which 85 cases succeeded, with the success rate of 94.4%. Among them, villi chromosome abnormalities were found in 50 cases, including 39 cases with abnormal chromosome numbers, 11 cases with abnormal chromosome structure, and the total abnormal rate was 58.8%. In addition, the villi chromosome abnormality rate of patients with recurrent missed abortion (≥2 times) and first missed abortion were 61.7% and 55.2%, respectively, and the difference was not significant (P>0.05). The villi chromosome abnormality rate of pregnant women with age≥35 years old was 71.1%, while the pregnant women with aged <35 years old was 45% (P<0.05). Chromosome abnormality is an important cause of missed abortion; villi chromosome abnormality rate has nothing to do with the number of missed abortion; pregnant woman with age≥35 years old is risk factor of the villi chromosome abnormality.

  2. Sex chromosome drive.

    PubMed

    Helleu, Quentin; Gérard, Pierre R; Montchamp-Moreau, Catherine

    2014-12-18

    Sex chromosome drivers are selfish elements that subvert Mendel's first law of segregation and therefore are overrepresented among the products of meiosis. The sex-biased progeny produced then fuels an extended genetic conflict between the driver and the rest of the genome. Many examples of sex chromosome drive are known, but the occurrence of this phenomenon is probably largely underestimated because of the difficulty to detect it. Remarkably, nearly all sex chromosome drivers are found in two clades, Rodentia and Diptera. Although very little is known about the molecular and cellular mechanisms of drive, epigenetic processes such as chromatin regulation could be involved in many instances. Yet, its evolutionary consequences are far-reaching, from the evolution of mating systems and sex determination to the emergence of new species. Copyright © 2015 Cold Spring Harbor Laboratory Press; all rights reserved.

  3. Sex Chromosome Drive

    PubMed Central

    Helleu, Quentin; Gérard, Pierre R.; Montchamp-Moreau, Catherine

    2015-01-01

    Sex chromosome drivers are selfish elements that subvert Mendel's first law of segregation and therefore are overrepresented among the products of meiosis. The sex-biased progeny produced then fuels an extended genetic conflict between the driver and the rest of the genome. Many examples of sex chromosome drive are known, but the occurrence of this phenomenon is probably largely underestimated because of the difficulty to detect it. Remarkably, nearly all sex chromosome drivers are found in two clades, Rodentia and Diptera. Although very little is known about the molecular and cellular mechanisms of drive, epigenetic processes such as chromatin regulation could be involved in many instances. Yet, its evolutionary consequences are far-reaching, from the evolution of mating systems and sex determination to the emergence of new species. PMID:25524548

  4. Behavior of Aberrant Chromosome Configurations in Drosophila melanogaster Female Meiosis I

    PubMed Central

    Gilliland, William D.; Colwell, Eileen M.; Lane, Fiona M.; Snouffer, Ashley A.

    2014-01-01

    One essential role of the first meiotic division is to reduce chromosome number by half. Although this is normally accomplished by segregating homologous chromosomes from each other, it is possible for a genome to have one or more chromosomes that lack a homolog (such as compound chromosomes), or have chromosomes with multiple potential homologs (such as in XXY females). These configurations complete meiosis but engage in unusual segregation patterns. In Drosophila melanogaster females carrying two compound chromosomes, the compounds can accurately segregate from each other, a process known as heterologous segregation. Similarly, in XXY females, when the X chromosomes fail to cross over, they often undergo secondary nondisjunction, where both Xs segregate away from the Y. Although both of these processes have been known for decades, the orientation mechanisms involved are poorly understood. Taking advantage of the recent discovery of chromosome congression in female meiosis I, we have examined a number of different aberrant chromosome configurations. We show that these genotypes complete congression normally, with their chromosomes bioriented at metaphase I arrest at the same rates that they segregate, indicating that orientation must be established during prometaphase I before congression. We also show that monovalent chromosomes can move out on the prometaphase I spindle, but the dot 4 chromosomes appear required for this movement. Finally, we show that, similar to achiasmate chromosomes, heterologous chromosomes can be connected by chromatin threads, suggesting a mechanism for how heterochromatic homology establishes these unusual biorientation patterns. PMID:25491942

  5. Behavior of aberrant chromosome configurations in Drosophila melanogaster female meiosis I.

    PubMed

    Gilliland, William D; Colwell, Eileen M; Lane, Fiona M; Snouffer, Ashley A

    2014-12-09

    One essential role of the first meiotic division is to reduce chromosome number by half. Although this is normally accomplished by segregating homologous chromosomes from each other, it is possible for a genome to have one or more chromosomes that lack a homolog (such as compound chromosomes), or have chromosomes with multiple potential homologs (such as in XXY females). These configurations complete meiosis but engage in unusual segregation patterns. In Drosophila melanogaster females carrying two compound chromosomes, the compounds can accurately segregate from each other, a process known as heterologous segregation. Similarly, in XXY females, when the X chromosomes fail to cross over, they often undergo secondary nondisjunction, where both Xs segregate away from the Y. Although both of these processes have been known for decades, the orientation mechanisms involved are poorly understood. Taking advantage of the recent discovery of chromosome congression in female meiosis I, we have examined a number of different aberrant chromosome configurations. We show that these genotypes complete congression normally, with their chromosomes bioriented at metaphase I arrest at the same rates that they segregate, indicating that orientation must be established during prometaphase I before congression. We also show that monovalent chromosomes can move out on the prometaphase I spindle, but the dot 4 chromosomes appear required for this movement. Finally, we show that, similar to achiasmate chromosomes, heterologous chromosomes can be connected by chromatin threads, suggesting a mechanism for how heterochromatic homology establishes these unusual biorientation patterns. Copyright © 2015 Gilliland et al.

  6. Genetic diagnosis of sex chromosome aberrations in horses based on parentage test by microsatellite DNA and analysis of X- and Y-linked markers.

    PubMed

    Kakoi, H; Hirota, K; Gawahara, H; Kurosawa, M; Kuwajima, M

    2005-03-01

    Sex chromosome aberrations are often associated with clinical signs that affect equine health and reproduction. However, abnormal manifestation with sex chromosome aberration usually appears at maturity and potential disorders may be suspected infrequently. A reliable survey at an early stage is therefore required. To detect and characterise sex chromosome aberrations in newborn foals by the parentage test and analysis using X- and Y-linked markers. We conducted a genetic diagnosis combined with a parentage test by microsatellite DNA and analysis of X- and Y-linked genetic markers in newborn light-breed foals (n = 17, 471). The minimum incidence of sex chromosome aberration in horses was estimated in the context of available population data. Eighteen cases with aberrations involving 63,XO, 65,XXY and 65,XXX were found. The XO, XXY (pure 65,XXY and/or mosaics/chimaeras) and XXX were found in 0.15, 0.02 and 0.01% of the population, respectively, based solely on detection of abnormal segregation of a single X chromosome marker, LEX003. Detection at an early age and understanding of the prevalence of sex chromosome aberrations should assist in the diagnosis and managment of horses kept for breeding. Further, the parental origin of the X chromosome of each disorder could be proved by the results of genetic analysis, thereby contributing to cytogenetic characterisation.

  7. Sister chromatid segregation in meiosis II

    PubMed Central

    Wassmann, Katja

    2013-01-01

    Meiotic divisions (meiosis I and II) are specialized cell divisions to generate haploid gametes. The first meiotic division with the separation of chromosomes is named reductional division. The second division, which takes place immediately after meiosis I without intervening S-phase, is equational, with the separation of sister chromatids, similar to mitosis. This meiotic segregation pattern requires the two-step removal of the cohesin complex holding sister chromatids together: cohesin is removed from chromosome arms that have been subjected to homologous recombination in meiosis I and from the centromere region in meiosis II. Cohesin in the centromere region is protected from removal in meiosis I, but this protection has to be removed—deprotected”—for sister chromatid segregation in meiosis II. Whereas the mechanisms of cohesin protection are quite well understood, the mechanisms of deprotection have been largely unknown until recently. In this review I summarize our current knowledge on cohesin deprotection. PMID:23574717

  8. Driving Apart and Segregating Genomes in Archaea.

    PubMed

    Barillà, Daniela

    2016-12-01

    Genome segregation is a fundamental biological process in organisms from all domains of life. How this stage of the cell cycle unfolds in Eukarya has been clearly defined and considerable progress has been made to unravel chromosome partition in Bacteria. The picture is still elusive in Archaea. The lineages of this domain exhibit different cell-cycle lifestyles and wide-ranging chromosome copy numbers, fluctuating from 1 up to 55. This plurality of patterns suggests that a variety of mechanisms might underpin disentangling and delivery of DNA molecules to daughter cells. Here I describe recent developments in archaeal genome maintenance, including investigations of novel genome segregation machines that point to unforeseen bacterial and eukaryotic connections. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  9. Partial monosomy and partial trisomy for different segments of chromosome 13 in several individuals of the same family.

    PubMed

    Wilroy, R S; Summitt, R L; Martens, P; Gooch, W M

    1977-12-01

    A reciprocal translocation, 46,XX,rcp(13;17)(q13;p13), was found to be segregating in a family. Two children have duplication of the distal portion of the long arm of chromosome 13, 46,XX,der(17),rcp(13;17)(q13;p13)mat. They are mentally retarded, have long philtra and postaxial hexadactyly. A maternal half-uncle has a duplication of the short arm and proximal portion of the long arm of chromosome 13, 47,XY,+der(13),rcp (13;17)(q13;p13)mat. He is mentally retarded, has scalp and skull defects and a very short philtrum. A fetus was found, on analysis of amniotic fluid cells, to have a deletion of the distal portion of the long arm of chromosome 13, 46,XX,der,(13),rcp(13;17)(q13;p13)mat. The fetus had multiple internal abnormalities and only 4 fingers on each hand.

  10. An Autosomal Factor from Drosophila Arizonae Restores Normal Spermatogenesis in Drosophila Mojavensis Males Carrying the D. Arizonae Y Chromosome

    PubMed Central

    Pantazidis, A. C.; Galanopoulos, V. K.; Zouros, E.

    1993-01-01

    Males of Drosophila mojavensis whose Y chromosome is replaced by the Y chromosome of the sibling species Drosophila arizonae are sterile. It is shown that genetic material from the fourth chromosome of D. arizonae is necessary and sufficient, in single dose, to restore fertility in these males. In introgression and mapping experiments this material segregates as a single Mendelian factor (sperm motility factor, SMF). Light and electron microscopy studies of spermatogenesis in D. mojavensis males whose Y chromosome is replaced by introgression with the Y chromosome of D. arizonae (these males are symbolized as mojY(a)) revealed postmeiotic abnormalities all of which are restored when the SMF of D. arizonae is co-introgressed (these males are symbolized as mojY(a)SMF(a)). The number of mature sperm per bundle in mojY(a)SMF(a) is slightly less than in pure D. mojavensis and is even smaller in males whose fertility is rescued by introgression of the entire fourth chromosome of D. arizonae. These observations establish an interspecific incompatibility between the Y chromosome and an autosomal factor (or more than one tightly linked factors) that can be useful for the study of the evolution of male hybrid sterility in Drosophila and the genetic control of spermatogenesis. PMID:8514139

  11. Siblings with opposite chromosome constitutions, dup(2q)/del(7q) and del(2q)/dup(7q).

    PubMed

    Shim, Sung Han; Shim, Jae Sun; Min, Kyunghoon; Lee, Hee Song; Park, Ji Eun; Park, Sang Hee; Hwang, Euna; Kim, Minyoung

    2014-01-15

    Chromosome 7q36 microdeletion syndrome is a rare genomic disorder characterized by underdevelopment of the brain, microcephaly, anomalies of the sex organs, and language problems. Developmental delay, intellectual disability, autistic spectrum disorders, BDMR syndrome, and unusual facial morphology are the key features of the chromosome 2q37 microdeletion syndrome. A genetic screening for two brothers with global developmental delay using high-resolution chromosomal analysis and subtelomeric multiplex ligation-dependent probe amplification revealed subtelomeric rearrangements on the same sites of 2q37.2 and 7q35, with reversed deletion and duplication. Both of them showed dysmorphic facial features, severe disability of physical and intellectual development, and abnormal genitalia with differential abnormalities in their phenotypes. The family did not have abnormal genetic phenotypes. According to the genetic analysis of their parents, adjacent-1 segregation from their mother's was suggested as a mechanism of their gene mutation. By comparing the phenotypes of our patients with previous reports on similar patients, we tried to obtain the information of related genes and their chromosomal locations. © 2013.

  12. Chromosomal Translocations: Chicken or Egg? | Center for Cancer Research

    Cancer.gov

    Many tumor cells have abnormal chromosomes. Some of these abnormalities are caused by chromosomal translocations, which occur when two chromosomes break and incorrectly rejoin, resulting in an exchange of genetic material. Translocations can activate oncogenes, silence tumor suppressor genes, or result in the creation of completely new fusion gene products. While there is

  13. Familial Isolated Clubfoot Is Associated with Recurrent Chromosome 17q23.1q23.2 Microduplications Containing TBX4

    PubMed Central

    Alvarado, David M.; Aferol, Hyuliya; McCall, Kevin; Huang, Jason B.; Techy, Matthew; Buchan, Jillian; Cady, Janet; Gonzales, Patrick R.; Dobbs, Matthew B.; Gurnett, Christina A.

    2010-01-01

    Clubfoot is a common musculoskeletal birth defect for which few causative genes have been identified. To identify the genes responsible for isolated clubfoot, we screened for genomic copy-number variants with the Affymetrix Genome-wide Human SNP Array 6.0. A recurrent chromosome 17q23.1q23.2 microduplication was identified in 3 of 66 probands with familial isolated clubfoot. The chromosome 17q23.1q23.2 microduplication segregated with autosomal-dominant clubfoot in all three families but with reduced penetrance. Mild short stature was common and one female had developmental hip dysplasia. Subtle skeletal abnormalities consisted of broad and shortened metatarsals and calcanei, small distal tibial epiphyses, and thickened ischia. Several skeletal features were opposite to those described in the reciprocal chromosome 17q23.1q23.2 microdeletion syndrome associated with developmental delay and cardiac and limb abnormalities. Of note, during our study, we also identified a microdeletion at the locus in a sibling pair with isolated clubfoot. The chromosome 17q23.1q23.2 region contains the T-box transcription factor TBX4, a likely target of the bicoid-related transcription factor PITX1 previously implicated in clubfoot etiology. Our result suggests that this chromosome 17q23.1q23.2 microduplication is a relatively common cause of familial isolated clubfoot and provides strong evidence linking clubfoot etiology to abnormal early limb development. PMID:20598276

  14. Income inequality and income segregation.

    PubMed

    Reardon, Sean F; Bischoff, Kendra

    2011-01-01

    This article investigates how the growth in income inequality from 1970 to 2000 affected patterns of income segregation along three dimensions: the spatial segregation of poverty and affluence, race-specific patterns of income segregation, and the geographic scale of income segregation. The evidence reveals a robust relationship between income inequality and income segregation, an effect that is larger for black families than for white families. In addition, income inequality affects income segregation primarily through its effect on the large-scale spatial segregation of affluence rather than by affecting the spatial segregation of poverty or by altering small-scale patterns of income segregation.

  15. Bayesian linkage and segregation analysis: factoring the problem.

    PubMed

    Matthysse, S

    2000-01-01

    Complex segregation analysis and linkage methods are mathematical techniques for the genetic dissection of complex diseases. They are used to delineate complex modes of familial transmission and to localize putative disease susceptibility loci to specific chromosomal locations. The computational problem of Bayesian linkage and segregation analysis is one of integration in high-dimensional spaces. In this paper, three available techniques for Bayesian linkage and segregation analysis are discussed: Markov Chain Monte Carlo (MCMC), importance sampling, and exact calculation. The contribution of each to the overall integration will be explicitly discussed.

  16. Wolfram syndrome maps to distal human chromosome 4p

    SciTech Connect

    Polymeropoulos, M.H.; Swift, R.; Swift, M.

    Wolfram syndrome (MIM 222300) is an autosomal recessive disorder defined by the occurrence of diabetes mellitus and progressive bilateral optic atrophy. Wolfram syndrome homozygotes develop widespread nervous system abnormalities; in particular, they exhibit severe behavioral difficulties that often lead to suicide attempts or psychiatric hospitalizations. The Wolfram syndrome gene also predisposes heterozygous carriers to psychiatric disorders. Since these heterozygotes are common in the general population, the Wolfram syndrome gene may contribute significantly to the overall burden of psychiatric illness. Based on a linkage analysis of 11 families segregating for this syndrome, using microsatellite repeat polymorphisms throughout the human genome, wemore » found the Wolfram syndrome gene to be linked to markers on the short arm of human chromosome 4, with Zmax=6.46 at {theta}=0.02 for marker D4S431.« less

  17. Segregation and Civic Virtue

    ERIC Educational Resources Information Center

    Merry, Michael S.

    2012-01-01

    In this essay Michael Merry defends the following prima facie argument: that civic virtue is not dependent on integration and in fact may be best fostered under conditions of segregation. He demonstrates that civic virtue can and does take place under conditions of involuntary segregation, but that voluntary separation--as a response to…

  18. Alternative meiotic chromatid segregation in the holocentric plant Luzula elegans

    PubMed Central

    Heckmann, Stefan; Jankowska, Maja; Schubert, Veit; Kumke, Katrin; Ma, Wei; Houben, Andreas

    2014-01-01

    Holocentric chromosomes occur in a number of independent eukaryotic lineages. They form holokinetic kinetochores along the entire poleward chromatid surfaces, and owing to this alternative chromosome structure, species with holocentric chromosomes cannot use the two-step loss of cohesion during meiosis typical for monocentric chromosomes. Here we show that the plant Luzula elegans maintains a holocentric chromosome architecture and behaviour throughout meiosis, and in contrast to monopolar sister centromere orientation, the unfused holokinetic sister centromeres behave as two distinct functional units during meiosis I, resulting in sister chromatid separation. Homologous non-sister chromatids remain terminally linked after metaphase I, by satellite DNA-enriched chromatin threads, until metaphase II. They then separate at anaphase II. Thus, an inverted sequence of meiotic sister chromatid segregation occurs. This alternative meiotic process is most likely one possible adaptation to handle a holocentric chromosome architecture and behaviour during meiosis. PMID:25296379

  19. Autism Spectrum Disorders Associated with Chromosomal Abnormalities

    ERIC Educational Resources Information Center

    Lo-Castro, Adriana; Benvenuto, Arianna; Galasso, Cinzia; Porfirio, Cristina; Curatolo, Paolo

    2010-01-01

    Autism spectrum disorders (ASDs) constitute a class of severe neurodevelopmental conditions with complex multifactorial and heterogeneous etiology. Despite high estimates of heritability, genetic causes of ASDs remain elusive, due to a high degree of genetic and phenotypic heterogeneity. So far, several "monogenic" forms of autism have been…

  20. Function of the Sex Chromosomes in Mammalian Fertility

    PubMed Central

    Heard, Edith; Turner, James

    2011-01-01

    The sex chromosomes play a highly specialized role in germ cell development in mammals, being enriched in genes expressed in the testis and ovary. Sex chromosome abnormalities (e.g., Klinefelter [XXY] and Turner [XO] syndrome) constitute the largest class of chromosome abnormalities and the commonest genetic cause of infertility in humans. Understanding how sex-gene expression is regulated is therefore critical to our understanding of human reproduction. Here, we describe how the expression of sex-linked genes varies during germ cell development; in females, the inactive X chromosome is reactivated before meiosis, whereas in males the X and Y chromosomes are inactivated at this stage. We discuss the epigenetics of sex chromosome inactivation and how this process has influenced the gene content of the mammalian X and Y chromosomes. We also present working models for how perturbations in sex chromosome inactivation or reactivation result in subfertility in the major classes of sex chromosome abnormalities. PMID:21730045

  1. Aneuploidy in spermatids of Robertsonian (Rb) chromosome heterozygous mice.

    PubMed

    Manieu, Catalina; González, Marisel; López-Fenner, Julio; Page, Jesús; Ayarza, Eliana; Fernández-Donoso, Raúl; Berríos, Soledad

    2014-12-01

    Rb translocations are chromosomal rearrangements frequently found in natural populations of the house mouse Mus musculus domesticus. The standard diploid karyotype of the house mouse consisting of 40 telocentric chromosomes may be reduced by the emergence of metacentric Rb chromosomes. Multiple simple Rb heterozygotes form trivalents exhibiting higher anaphase nondisjunction frequency and consequently higher number of unbalanced gametes than in normal males. This work will attempt to establish whether frequencies of aneuploidy observed in heterozygote spermatids of the house mouse M. musculus domesticus show differences in chromosomes derived from different trivalents. Towards this goal, the number and distribution frequency of aneuploidy was assessed via FISH staining of specific chromosomes of spermatids derived from 2n = 32 individuals. Our results showed that for a given set of target chromosomes, 90% of the gametes were balanced, resulting from alternate segregation, and that there were no differences (approx. 10%) in aneuploidy frequencies in chromosomes derived from different trivalents. These observations suggest that segregation effectiveness does not depend on the type of chromosomes involved in trivalents. As a consequence of the trivalent's configuration, joint segregation of the telocentric chromosomes occurs thus favoring their appearance together in early spermatids. Our data suggest that Rb chromosomes and their telocentric homologs are subject to architectural constraints placing them close to each other. This proximity may ultimately facilitate fusion between them, hence contributing to a prevalence of Rb metacentric chromosomes.

  2. Chromosomal Translocations: Chicken or Egg? | Center for Cancer Research

    Cancer.gov

    Many tumor cells have abnormal chromosomes. Some of these abnormalities are caused by chromosomal translocations, which occur when two chromosomes break and incorrectly rejoin, resulting in an exchange of genetic material. Translocations can activate oncogenes, silence tumor suppressor genes, or result in the creation of completely new fusion gene products. While there is little doubt that chromosomal translocations can contribute to cancer, there is an active "chicken and the egg" discussion about the role translocations and other chromosomal abnormalities play—do they actually cause cancer or merely occur because of other changes within the cancer cell.  

  3. Evolutionary dynamics of adult stem cells: Comparison of random and immortal-strand segregation mechanisms

    NASA Astrophysics Data System (ADS)

    Tannenbaum, Emmanuel; Sherley, James L.; Shakhnovich, Eugene I.

    2005-04-01

    This paper develops a point-mutation model describing the evolutionary dynamics of a population of adult stem cells. Such a model may prove useful for quantitative studies of tissue aging and the emergence of cancer. We consider two modes of chromosome segregation: (1) random segregation, where the daughter chromosomes of a given parent chromosome segregate randomly into the stem cell and its differentiating sister cell and (2) “immortal DNA strand” co-segregation, for which the stem cell retains the daughter chromosomes with the oldest parent strands. Immortal strand co-segregation is a mechanism, originally proposed by [Cairns Nature (London) 255, 197 (1975)], by which stem cells preserve the integrity of their genomes. For random segregation, we develop an ordered strand pair formulation of the dynamics, analogous to the ordered strand pair formalism developed for quasispecies dynamics involving semiconservative replication with imperfect lesion repair (in this context, lesion repair is taken to mean repair of postreplication base-pair mismatches). Interestingly, a similar formulation is possible with immortal strand co-segregation, despite the fact that this segregation mechanism is age dependent. From our model we are able to mathematically show that, when lesion repair is imperfect, then immortal strand co-segregation leads to better preservation of the stem cell lineage than random chromosome segregation. Furthermore, our model allows us to estimate the optimal lesion repair efficiency for preserving an adult stem cell population for a given period of time. For human stem cells, we obtain that mispaired bases still present after replication and cell division should be left untouched, to avoid potentially fixing a mutation in both DNA strands.

  4. Evolutionary dynamics of adult stem cells: comparison of random and immortal-strand segregation mechanisms.

    PubMed

    Tannenbaum, Emmanuel; Sherley, James L; Shakhnovich, Eugene I

    2005-04-01

    This paper develops a point-mutation model describing the evolutionary dynamics of a population of adult stem cells. Such a model may prove useful for quantitative studies of tissue aging and the emergence of cancer. We consider two modes of chromosome segregation: (1) random segregation, where the daughter chromosomes of a given parent chromosome segregate randomly into the stem cell and its differentiating sister cell and (2) "immortal DNA strand" co-segregation, for which the stem cell retains the daughter chromosomes with the oldest parent strands. Immortal strand co-segregation is a mechanism, originally proposed by [Cairns Nature (London) 255, 197 (1975)], by which stem cells preserve the integrity of their genomes. For random segregation, we develop an ordered strand pair formulation of the dynamics, analogous to the ordered strand pair formalism developed for quasispecies dynamics involving semiconservative replication with imperfect lesion repair (in this context, lesion repair is taken to mean repair of postreplication base-pair mismatches). Interestingly, a similar formulation is possible with immortal strand co-segregation, despite the fact that this segregation mechanism is age dependent. From our model we are able to mathematically show that, when lesion repair is imperfect, then immortal strand co-segregation leads to better preservation of the stem cell lineage than random chromosome segregation. Furthermore, our model allows us to estimate the optimal lesion repair efficiency for preserving an adult stem cell population for a given period of time. For human stem cells, we obtain that mispaired bases still present after replication and cell division should be left untouched, to avoid potentially fixing a mutation in both DNA strands.

  5. Mps1 phosphorylation of condensin II controls chromosome condensation at the onset of mitosis.

    PubMed

    Kagami, Yuya; Nihira, Keishi; Wada, Shota; Ono, Masaya; Honda, Mariko; Yoshida, Kiyotsugu

    2014-06-23

    During mitosis, genomic DNA is condensed into chromosomes to promote its equal segregation into daughter cells. Chromosome condensation occurs during cell cycle progression from G2 phase to mitosis. Failure of chromosome compaction at prophase leads to subsequent misregulation of chromosomes. However, the molecular mechanism that controls the early phase of mitotic chromosome condensation is largely unknown. Here, we show that Mps1 regulates initial chromosome condensation during mitosis. We identify condensin II as a novel Mps1-associated protein. Mps1 phosphorylates one of the condensin II subunits, CAP-H2, at Ser492 during mitosis, and this phosphorylation event is required for the proper loading of condensin II on chromatin. Depletion of Mps1 inhibits chromosomal targeting of condensin II and accurate chromosome condensation during prophase. These findings demonstrate that Mps1 governs chromosomal organization during the early stage of mitosis to facilitate proper chromosome segregation. © 2014 Kagami et al.

  6. Mps1 phosphorylation of condensin II controls chromosome condensation at the onset of mitosis

    PubMed Central

    Kagami, Yuya; Nihira, Keishi; Wada, Shota; Ono, Masaya; Honda, Mariko

    2014-01-01

    During mitosis, genomic DNA is condensed into chromosomes to promote its equal segregation into daughter cells. Chromosome condensation occurs during cell cycle progression from G2 phase to mitosis. Failure of chromosome compaction at prophase leads to subsequent misregulation of chromosomes. However, the molecular mechanism that controls the early phase of mitotic chromosome condensation is largely unknown. Here, we show that Mps1 regulates initial chromosome condensation during mitosis. We identify condensin II as a novel Mps1-associated protein. Mps1 phosphorylates one of the condensin II subunits, CAP-H2, at Ser492 during mitosis, and this phosphorylation event is required for the proper loading of condensin II on chromatin. Depletion of Mps1 inhibits chromosomal targeting of condensin II and accurate chromosome condensation during prophase. These findings demonstrate that Mps1 governs chromosomal organization during the early stage of mitosis to facilitate proper chromosome segregation. PMID:24934155

  7. Chromosomal Aneuploidies and Early Embryonic Developmental Arrest.

    PubMed

    Maurer, Maria; Ebner, Thomas; Puchner, Manuela; Mayer, Richard Bernhard; Shebl, Omar; Oppelt, Peter; Duba, Hans-Christoph

    2015-01-01

    Selecting the best embryo for transfer, with the highest chance of achieving a vital pregnancy, is a major goal in current in vitro fertilization (IVF) technology. The high rate of embryonic developmental arrest during IVF treatment is one of the limitations in achieving this goal. Chromosomal abnormalities are possibly linked with chromosomal arrest and selection against abnormal fertilization products. The objective of this study was to evaluate the frequency and type of chromosomal abnormalities in preimplantation embryos with developmental arrest. This cohort study included blastomeres of embryos with early developmental arrest that were biopsied and analyzed by fluorescence in-situ hybridization (FISH) with probes for chromosomes 13, 16, 18, 21 and 22. Forty-five couples undergoing IVF treatment were included, and 119 arrested embryos were biopsied. All probes were obtained from the Kinderwunsch Zentrum, Linz, Austria, between August 2009 and August 2011. Of these embryos, 31.6% were normal for all chromosomes tested, and 68.4% were abnormal. Eleven embryos were uniformly aneuploid, 20 were polyploid, 3 were haploid, 11 displayed mosaicism and 22 embryos exhibited chaotic chromosomal complement. Nearly 70% of arrested embryos exhibit chromosomal errors, making chromosomal abnormalities a major cause of embryonic arrest and may be a further explanation for the high developmental failure rates during culture of the embryos in the IVF setting.

  8. Chromosomal Aneuploidies and Early Embryonic Developmental Arrest

    PubMed Central

    Maurer, Maria; Ebner, Thomas; Puchner, Manuela; Mayer, Richard Bernhard; Shebl, Omar; Oppelt, Peter; Duba, Hans-Christoph

    2015-01-01

    Background Selecting the best embryo for transfer, with the highest chance of achieving a vital pregnancy, is a major goal in current in vitro fertilization (IVF) technology. The high rate of embryonic developmental arrest during IVF treatment is one of the limitations in achieving this goal. Chromosomal abnormalities are possibly linked with chromosomal arrest and selection against abnormal fertilization products. The objective of this study was to evaluate the frequency and type of chromosomal abnormalities in preimplantation embryos with developmental arrest. Materials and Methods This cohort study included blastomeres of embryos with early developmental arrest that were biopsied and analyzed by fluorescence in-situ hybridization (FISH) with probes for chromosomes 13, 16, 18, 21 and 22. Forty-five couples undergoing IVF treatment were included, and 119 arrested embryos were biopsied. All probes were obtained from the Kinderwunsch Zentrum, Linz, Austria, between August 2009 and August 2011. Results Of these embryos, 31.6% were normal for all chromosomes tested, and 68.4% were abnormal. Eleven embryos were uniformly aneuploid, 20 were polyploid, 3 were haploid, 11 displayed mosaicism and 22 embryos exhibited chaotic chromosomal complement. Conclusion Nearly 70% of arrested embryos exhibit chromosomal errors, making chromosomal abnormalities a major cause of embryonic arrest and may be a further explanation for the high developmental failure rates during culture of the embryos in the IVF setting. PMID:26644858

  9. Chromosome rearrangements in canine fibrosarcomas.

    PubMed

    Sargan, D R; Milne, B S; Hernandez, J Aguirre; O'Brien, P C M; Ferguson-Smith, M A; Hoather, T; Dobson, J M

    2005-01-01

    We have previously reported the use of six- and seven-color paint sets in the analysis of canine soft tissue sarcomas. Here we combine this technique with flow sorting of translocation chromosomes, reverse painting, and polymerase chain reaction (PCR) analysis of the gene content of the reverse paint in order to provide a more detailed analysis of cytogenetic abnormalities in canine tumors. We examine two fibrosarcomas, both from female Labrador retrievers, and show abnormalities in chromosomes 11 and 30 in both cases. Evidence of involvement of TGFBR1 is presented for one tumor.

  10. Automated clinical system for chromosome analysis

    NASA Technical Reports Server (NTRS)

    Castleman, K. R.; Friedan, H. J.; Johnson, E. T.; Rennie, P. A.; Wall, R. J. (Inventor)

    1978-01-01

    An automatic chromosome analysis system is provided wherein a suitably prepared slide with chromosome spreads thereon is placed on the stage of an automated microscope. The automated microscope stage is computer operated to move the slide to enable detection of chromosome spreads on the slide. The X and Y location of each chromosome spread that is detected is stored. The computer measures the chromosomes in a spread, classifies them by group or by type and also prepares a digital karyotype image. The computer system can also prepare a patient report summarizing the result of the analysis and listing suspected abnormalities.

  11. DNA-damage response during mitosis induces whole-chromosome missegregation.

    PubMed

    Bakhoum, Samuel F; Kabeche, Lilian; Murnane, John P; Zaki, Bassem I; Compton, Duane A

    2014-11-01

    Many cancers display both structural (s-CIN) and numerical (w-CIN) chromosomal instabilities. Defective chromosome segregation during mitosis has been shown to cause DNA damage that induces structural rearrangements of chromosomes (s-CIN). In contrast, whether DNA damage can disrupt mitotic processes to generate whole chromosomal instability (w-CIN) is unknown. Here, we show that activation of the DNA-damage response (DDR) during mitosis selectively stabilizes kinetochore-microtubule (k-MT) attachments to chromosomes through Aurora-A and PLK1 kinases, thereby increasing the frequency of lagging chromosomes during anaphase. Inhibition of DDR proteins, ATM or CHK2, abolishes the effect of DNA damage on k-MTs and chromosome segregation, whereas activation of the DDR in the absence of DNA damage is sufficient to induce chromosome segregation errors. Finally, inhibiting the DDR during mitosis in cancer cells with persistent DNA damage suppresses inherent chromosome segregation defects. Thus, the DDR during mitosis inappropriately stabilizes k-MTs, creating a link between s-CIN and w-CIN. The genome-protective role of the DDR depends on its ability to delay cell division until damaged DNA can be fully repaired. Here, we show that when DNA damage is induced during mitosis, the DDR unexpectedly induces errors in the segregation of entire chromosomes, thus linking structural and numerical chromosomal instabilities. ©2014 American Association for Cancer Research.

  12. Centromere pairing – tethering partner chromosomes in meiosis I

    PubMed Central

    Kurdzo, Emily L; Dawson, Dean S

    2015-01-01

    In meiosis, homologous chromosomes face the obstacle of finding, holding onto and segregating away from their partner chromosome. There is increasing evidence, in a diverse range of organisms, that centromere–centromere interactions that occur in late prophase are an important mechanism in ensuring segregation fidelity. Centromere pairing appears to initiate when homologous chromosomes synapse in meiotic prophase. Structural proteins of the synaptonemal complex have been shown to help mediate centromere pairing, but how the structure that maintains centromere pairing differs from the structure of the synaptonemal complex along the chromosomal arms remains unknown. When the synaptonemal complex proteins disassemble from the chromosome arms in late prophase, some of these synaptonemal complex components persist at the centromeres. In yeast and Drosophila these centromere-pairing behaviors promote the proper segregation of chromosome partners that have failed to become linked by chiasmata. Recent studies of mouse spermatocytes have described centromere pairing behaviors that are similar in several respects to what has been described in the fly and yeast systems. In humans, chromosomes that fail to experience crossovers in meiosis are error-prone and are a major source of aneuploidy. The finding that centromere pairing is a conserved phenomenon raises the possibility that it may play a role in promoting the segregation fidelity of non-exchange chromosome pairs in humans. PMID:25817724

  13. Understanding Segregation Processes

    NASA Astrophysics Data System (ADS)

    Bruch, Elizabeth

    There is growing consensus that living in neighborhoods of concentrated poverty increases the likelihood of social problems such as teenage parenthood, drug and alcohol use, crime victimization, and chronic unemployment. Neighborhood inequality is also implicated in studies of enduring race/ethnic health disparities, and there are recent moves to broaden the definition of health care policy to policies targeting social inequality (Mechanic 2007). Residential segregation affects health outcomes in several different ways. First, income, education, and occupation are all strongly related to health (Adler and Newman 2002). Segregation is a key mechanism through which socioeconomic inequality is perpetuated and reinforced, as it hinders the upward mobility of disadvantaged groups by limiting their educational and employment opportunities. Second, segregation increases minority exposure to unhealthy neighborhood environments. Residential segregation creates areas with concentrated poverty and unemployment, both of which are key factors that predict violence and create racial differences in homicide (Samson and Wilson 1995). Neighborhood characteristics, such as exposure to environmental hazards, fear of violence, and access to grocery stores, affect health risks and health behaviors (Cheadle et al. 1991). Tobacco and alcohol industries also advertise their products disproportionately in poor, minority areas (Moore, Williams, and Qualls 1996). Finally, residential segregation leads to inequalitie in health care resources, which contributes to disparities in quality of treatment (Smedley, Stith, and Nelson 2002).

  14. Modeling Chromosomes

    ERIC Educational Resources Information Center

    Robertson, Carol

    2016-01-01

    Learning about chromosomes is standard fare in biology classrooms today. However, students may find it difficult to understand the relationships among the "genome", "chromosomes", "genes", a "gene locus", and "alleles". In the simple activity described in this article, which follows the 5E approach…

  15. Chromosomal Flexibility

    ERIC Educational Resources Information Center

    Journal of College Science Teaching, 2005

    2005-01-01

    Scientists have shown that a genetic element on one chromosome may direct gene activity on another. Howard Hughes Medical Institute (HHMI) researchers report that a multitasking master-control region appears to over-see both a set of its own genes and a related gene on a nearby chromosome. The findings reinforce the growing importance of location…

  16. Centromeric Heterochromatin: The Primordial Segregation Machine

    PubMed Central

    Bloom, Kerry S.

    2014-01-01

    Centromeres are specialized domains of heterochromatin that provide the foundation for the kinetochore. Centromeric heterochromatin is characterized by specific histone modifications, a centromere-specific histone H3 variant (CENP-A), and the enrichment of cohesin, condensin, and topo-isomerase II. Centromere DNA varies orders of magnitude in size from 125 bp (budding yeast) to several megabases (human). In metaphase, sister kinetochores on the surface of replicated chromosomes face away from each other, where they establish microtubule attachment and bi-orientation. Despite the disparity in centromere size, the distance between separated sister kinetochores is remarkably conserved (approximately 1 μm) throughout phylogeny. The centromere functions as a molecular spring that resists microtubule-based extensional forces in mitosis. This review explores the physical properties of DNA in order to understand how the molecular spring is built and how it contributes to the fidelity of chromosome segregation. PMID:25251850

  17. Computational model for chromosomal instabilty

    NASA Astrophysics Data System (ADS)

    Zapperi, Stefano; Bertalan, Zsolt; Budrikis, Zoe; La Porta, Caterina

    2015-03-01

    Faithful segregation of genetic material during cell division requires alignment of the chromosomes between the spindle poles and attachment of their kinetochores to each of the poles. Failure of these complex dynamical processes leads to chromosomal instability (CIN), a characteristic feature of several diseases including cancer. While a multitude of biological factors regulating chromosome congression and bi-orientation have been identified, it is still unclear how they are integrated into a coherent picture. Here we address this issue by a three dimensional computational model of motor-driven chromosome congression and bi-orientation. Our model reveals that successful cell division requires control of the total number of microtubules: if this number is too small bi-orientation fails, while if it is too large not all the chromosomes are able to congress. The optimal number of microtubules predicted by our model compares well with early observations in mammalian cell spindles. Our results shed new light on the origin of several pathological conditions related to chromosomal instability.

  18. The functional role for condensin in the regulation of chromosomal organization during the cell cycle.

    PubMed

    Kagami, Yuya; Yoshida, Kiyotsugu

    2016-12-01

    In all organisms, the control of cell cycle progression is a fundamental process that is essential for cell growth, development, and survival. Through each cell cycle phase, the regulation of chromatin organization is essential for natural cell proliferation and maintaining cellular homeostasis. During mitosis, the chromatin morphology is dramatically changed to have a "thread-like" shape and the condensed chromosomes are segregated equally into two daughter cells. Disruption of the mitotic chromosome architecture physically impedes chromosomal behaviors, such as chromosome alignment and chromosome segregation; therefore, the proper mitotic chromosome structure is required to maintain chromosomal stability. Accumulating evidence has demonstrated that mitotic chromosome condensation is induced by condensin complexes. Moreover, recent studies have shown that condensin also modulates interphase chromatin and regulates gene expression. This review mainly focuses on the molecular mechanisms that condensin uses to exert its functions during the cell cycle progression. Moreover, we discuss the condensin-mediated chromosomal organization in cancer cells.

  19. The pairing center plays a key role in homolog paring: an explanation for adjacent-2 segregation in interchange heterozygotes.

    PubMed

    Luo, Peigao

    2009-05-01

    Having reflected on the discrepancy between various views of chromosome behavior during meiosis, we propose an alternative description of Mendel's first law of segregation by referring to the segregation of pairing centers instead of centromeres. We also propose an alternative description of Mendel's second law of independent assortment, which refers to the free combination of different pairing centers. This interpretation is based on the modified concept that true 'homologous chromosomes' should carry the pairing center rather than centromere: the length of homology or the importance of the homologous segment on the chromosome is the crucial factor in homologous chromosome pairing and synapsis.

  20. The Role of Residential Segregation in Contemporary School Segregation

    ERIC Educational Resources Information Center

    Frankenberg, Erica

    2013-01-01

    Inaction to address housing segregation in metropolitan areas has resulted in persistently high levels of residential segregation. As the Supreme Court has recently limited school districts' voluntary integration efforts, this article considers the role of residential segregation in maintaining racially isolated schools, namely what is known about…

  1. HIM-8 binds to the X chromosome pairing center and mediates chromosome-specific meiotic synapsis.

    PubMed

    Phillips, Carolyn M; Wong, Chihunt; Bhalla, Needhi; Carlton, Peter M; Weiser, Pinky; Meneely, Philip M; Dernburg, Abby F

    2005-12-16

    The him-8 gene is essential for proper meiotic segregation of the X chromosomes in C. elegans. Here we show that loss of him-8 function causes profound X chromosome-specific defects in homolog pairing and synapsis. him-8 encodes a C2H2 zinc-finger protein that is expressed during meiosis and concentrates at a site on the X chromosome known as the meiotic pairing center (PC). A role for HIM-8 in PC function is supported by genetic interactions between PC lesions and him-8 mutations. HIM-8 bound chromosome sites associate with the nuclear envelope (NE) throughout meiotic prophase. Surprisingly, a point mutation in him-8 that retains both chromosome binding and NE localization fails to stabilize pairing or promote synapsis. These observations indicate that stabilization of homolog pairing is an active process in which the tethering of chromosome sites to the NE may be necessary but is not sufficient.

  2. Imaging Chromosome Separation in Mouse Oocytes by Responsive 3D Confocal Timelapse Microscopy.

    PubMed

    Lane, Simon I R; Crouch, Stephen; Jones, Keith T

    2017-01-01

    Accurate chromosome segregation is necessary so that genetic material is equally shared among daughter cells. However, maturing mammalian oocytes are particularly prone to chromosome segregation errors, making them a valuable tool for identifying the causes of mis-segregation. Factors such as aging, cohesion loss, DNA damage, and the roles of a plethora of kinetochore and cell cycle-related proteins are involved. To study chromosome segregation in oocytes in a live setting is an imaging challenge that requires advanced techniques. Here we describe a method for examining chromosomes in live oocytes in detail as they undergo maturation. Our method is based on tracking the "center of brightness" of fluorescently labeled chromosomes. Here we describe how to set up our software and run experiments on a Leica TCS SP8 confocal microscope, but the method would be transferable to other microscopes with computer-aided microscopy.

  3. Residential Segregation and School Integration.

    ERIC Educational Resources Information Center

    Rivkin, Steven G.

    1994-01-01

    Asserts that school districts' efforts to integrate schools have failed to ameliorate the racial isolation of black students. Finds that schools remain segregated primarily because of continued residential segregation and that school integration efforts have had little long-term effect on residential segregation. (CFR)

  4. Chromosome Bridges Maintain Kinetochore-Microtubule Attachment throughout Mitosis and Rarely Break during Anaphase.

    PubMed

    Pampalona, Judit; Roscioli, Emanuele; Silkworth, William T; Bowden, Brent; Genescà, Anna; Tusell, Laura; Cimini, Daniela

    2016-01-01

    Accurate chromosome segregation during cell division is essential to maintain genome stability, and chromosome segregation errors are causally linked to genetic disorders and cancer. An anaphase chromosome bridge is a particular chromosome segregation error observed in cells that enter mitosis with fused chromosomes/sister chromatids. The widely accepted Breakage/Fusion/Bridge cycle model proposes that anaphase chromosome bridges break during mitosis to generate chromosome ends that will fuse during the following cell cycle, thus forming new bridges that will break, and so on. However, various studies have also shown a link between chromosome bridges and aneuploidy and/or polyploidy. In this study, we investigated the behavior and properties of chromosome bridges during mitosis, with the idea to gain insight into the potential mechanism underlying chromosome bridge-induced aneuploidy. We find that only a small number of chromosome bridges break during anaphase, whereas the rest persist through mitosis into the subsequent cell cycle. We also find that the microtubule bundles (k-fibers) bound to bridge kinetochores are not prone to breakage/detachment, thus supporting the conclusion that k-fiber detachment is not the cause of chromosome bridge-induced aneuploidy. Instead, our data suggest that while the microtubules bound to the kinetochores of normally segregating chromosomes shorten substantially during anaphase, the k-fibers bound to bridge kinetochores shorten only slightly, and may even lengthen, during anaphase. This causes some of the bridge kinetochores/chromosomes to lag behind in a position that is proximal to the cell/spindle equator and may cause the bridged chromosomes to be segregated into the same daughter nucleus or to form a micronucleus.

  5. Massively Parallel Sequencing Reveals the Complex Structure of an Irradiated Human Chromosome on a Mouse Background in the Tc1 Model of Down Syndrome

    PubMed Central

    Clayton, Stephen; Prigmore, Elena; Langley, Elizabeth; Yang, Fengtang; Maguire, Sean; Fu, Beiyuan; Rajan, Diana; Sheppard, Olivia; Scott, Carol; Hauser, Heidi; Stephens, Philip J.; Stebbings, Lucy A.; Ng, Bee Ling; Fitzgerald, Tomas; Quail, Michael A.; Banerjee, Ruby; Rothkamm, Kai; Tybulewicz, Victor L. J.; Fisher, Elizabeth M. C.; Carter, Nigel P.

    2013-01-01

    Down syndrome (DS) is caused by trisomy of chromosome 21 (Hsa21) and presents a complex phenotype that arises from abnormal dosage of genes on this chromosome. However, the individual dosage-sensitive genes underlying each phenotype remain largely unknown. To help dissect genotype – phenotype correlations in this complex syndrome, the first fully transchromosomic mouse model, the Tc1 mouse, which carries a copy of human chromosome 21 was produced in 2005. The Tc1 strain is trisomic for the majority of genes that cause phenotypes associated with DS, and this freely available mouse strain has become used widely to study DS, the effects of gene dosage abnormalities, and the effect on the basic biology of cells when a mouse carries a freely segregating human chromosome. Tc1 mice were created by a process that included irradiation microcell-mediated chromosome transfer of Hsa21 into recipient mouse embryonic stem cells. Here, the combination of next generation sequencing, array-CGH and fluorescence in situ hybridization technologies has enabled us to identify unsuspected rearrangements of Hsa21 in this mouse model; revealing one deletion, six duplications and more than 25 de novo structural rearrangements. Our study is not only essential for informing functional studies of the Tc1 mouse but also (1) presents for the first time a detailed sequence analysis of the effects of gamma radiation on an entire human chromosome, which gives some mechanistic insight into the effects of radiation damage on DNA, and (2) overcomes specific technical difficulties of assaying a human chromosome on a mouse background where highly conserved sequences may confound the analysis. Sequence data generated in this study is deposited in the ENA database, Study Accession number: ERP000439. PMID:23596509

  6. Partial hexasomy of chromosome 15.

    PubMed

    Huang, Bing; Bartley, James

    2003-09-01

    Marker chromosomes originating from chromosome 15, often referred to as inv dup(15), is the most common marker chromosome found in humans. The large marker 15 that contains the Prader-Willi syndrome (PWS)/Angelman syndrome (AS) chromosome region is usually associated with an abnormal phenotype of moderate to severe mental retardation, seizures, poor motor coordination, behavioral problems, and mild dysmorphic features. We report here an infant boy with two copies of the large inv dup(15). A 10-day-old infant was found to have infantile spasms, microcephaly, hypotonia, and lethargy. Lymphocyte chromosome analysis revealed a 48,XY, +2mar karyotype. Fluorescence in situ hybridization with probes rRNA, D15Z4, D15S11, and GABRB3 demonstrated that both markers were chromosome 15 in origin and contained the Prader-Willi/Angelman syndrome chromosome region. Therefore, this patient is hexasomic for the PWS/AS region. The phenotype of this patient does not appear to be significantly more severe than patients with one copy of the large inv dup(15) at birth, however, follow-up evaluation of the patient at 21 months of age shows that this patient has frequent and severe seizure activity, severe bilateral hearing loss, and cortical blindness. Copyright 2003 Wiley-Liss, Inc.

  7. Segregation by onset asynchrony.

    PubMed

    Hancock, P J B; Walton, L; Mitchell, G; Plenderleith, Y; Phillips, W A

    2008-08-05

    We describe a simple psychophysical paradigm for studying figure-ground segregation by onset asynchrony. Two pseudorandom arrays of Gabor patches are displayed, to left and right of fixation. Within one array, a subset of elements form a figure, such as a randomly curving path, that can only be reliably detected when their onset is not synchronized with that of the background elements. Several findings are reported. First, for most participants, segregation required an onset asynchrony of 20-40 ms. Second, detection was no better when the figure was presented first, and thus by itself, than when the background elements were presented first, even though in the latter case the figure could not be detected in either of the two successive displays alone. Third, asynchrony segregated subsets of randomly oriented elements equally well. Fourth, asynchronous onsets aligned with the path could be discriminated from those lying on the path but not aligned with it. Fifth, both transient and sustained neural activity contribute to detection. We argue that these findings are compatible with neural signaling by synchronized rate codes. Finally, schizophrenic disorganization is associated with reduced sensitivity. Thus, in addition to bearing upon basic theoretical issues, this paradigm may have clinical utility.

  8. Clinical and molecular genetic characterisation of a family segregating autosomal dominant retinitis pigmentosa and sensorineural deafness.

    PubMed

    Kenna, P; Mansergh, F; Millington-Ward, S; Erven, A; Kumar-Singh, R; Brennan, R; Farrar, G J; Humphries, P

    1997-03-01

    To characterise clinically a large kindred segregating retinitis pigmentosa and sensorineural hearing impairment in an autosomal dominant pattern and perform genetic linkage studies in this family. Extensive linkage analysis in this family had previously excluded the majority of loci shown to be involved in the aetiologies of RP, some other forms of inherited retinal degeneration, and inherited deafness. Members of the family were subjected to detailed ophthalmic and audiological assessment. In addition, some family members underwent skeletal muscle biopsy, electromyography, and electrocardiography. Linkage analysis using anonymous microsatellite markers was performed on DNA samples from all living members of the pedigree. Patients in this kindred have a retinopathy typical of retinitis pigmentosa in addition to a hearing impairment. Those members of the pedigree examined demonstrated a subclinical myopathy, as evidence by abnormal skeletal muscle histology, electromyography, and electrocardiography. LOD scores of Zmax = 3.75 (theta = 0.10), Zmax = 3.41 (theta = 0.10), and Zmax = 3.25 (theta = 0.15) respectively were obtained with the markers D9S118, D9S121, and ASS, located on chromosome 9q34-qter, suggesting that the causative gene in this family may lie on the long arm (q) of chromosome 9. These data indicate that the gene responsible for the phenotype in this kindred is located on chromosome 9 q. These data, together with evidence that a murine deafness gene is located in a syntenic area of the mouse genome, should direct the research community to consider this area as a candidate region for retinopathy and/or deafness genes.

  9. Chromosome Territories

    PubMed Central

    Cremer, Thomas; Cremer, Marion

    2010-01-01

    Chromosome territories (CTs) constitute a major feature of nuclear architecture. In a brief statement, the possible contribution of nuclear architecture studies to the field of epigenomics is considered, followed by a historical account of the CT concept and the final compelling experimental evidence of a territorial organization of chromosomes in all eukaryotes studied to date. Present knowledge of nonrandom CT arrangements, of the internal CT architecture, and of structural interactions with other CTs is provided as well as the dynamics of CT arrangements during cell cycle and postmitotic terminal differentiation. The article concludes with a discussion of open questions and new experimental strategies to answer them. PMID:20300217

  10. Mitotic chromosome compaction via active loop extrusion

    NASA Astrophysics Data System (ADS)

    Goloborodko, Anton; Imakaev, Maxim; Marko, John; Mirny, Leonid; MIT-Northwestern Team

    During cell division, two copies of each chromosome are segregated from each other and compacted more than hundred-fold into the canonical X-shaped structures. According to earlier microscopic observations and the recent Hi-C study, chromosomes are compacted into arrays of consecutive loops of ~100 kilobases. Mechanisms that lead to formation of such loop arrays are largely unknown. Here we propose that, during cell division, chromosomes can be compacted by enzymes that extrude loops on chromatin fibers. First, we use computer simulations and analytical modeling to show that a system of loop-extruding enzymes on a chromatin fiber self-organizes into an array of consecutive dynamic loops. Second, we model the process of loop extrusion in 3D and show that, coupled with the topo II strand-passing activity, it leads to robust compaction and segregation of sister chromatids. This mechanism of chromosomal condensation and segregation does not require additional proteins or specific DNA markup and is robust against variations in the number and properties of such loop extruding enzymes. Work at NU was supported by the NSF through Grants DMR-1206868 and MCB-1022117, and by the NIH through Grants GM105847 and CA193419. Work at MIT was supported by the NIH through Grants GM114190 R01HG003143.

  11. Small Molecule Disrupts Abnormal Gene Fusion Associated with Leukemia | Center for Cancer Research

    Cancer.gov

    Rare chromosomal abnormalities, called chromosomal translocations, in which part of a chromosome breaks off and becomes attached to another chromosome, can result in the generation of chimeric proteins. These aberrant proteins have unpredictable, and sometimes harmful, functions, including uncontrolled cell growth that can lead to cancer. One type of translocation, in which a

  12. The bacterial segrosome: a dynamic nucleoprotein machine for DNA trafficking and segregation.

    PubMed

    Hayes, Finbarr; Barillà, Daniela

    2006-02-01

    The genomes of unicellular and multicellular organisms must be partitioned equitably in coordination with cytokinesis to ensure faithful transmission of duplicated genetic material to daughter cells. Bacteria use sophisticated molecular mechanisms to guarantee accurate segregation of both plasmids and chromosomes at cell division. Plasmid segregation is most commonly mediated by a Walker-type ATPase and one of many DNA-binding proteins that assemble on a cis-acting centromere to form a nucleoprotein complex (the segrosome) that mediates intracellular plasmid transport. Bacterial chromosome segregation involves a multipartite strategy in which several discrete protein complexes potentially participate. Shedding light on the basis of genome segregation in bacteria could indicate new strategies aimed at combating pathogenic and antibiotic-resistant bacteria.

  13. Human Autoantibodies Reveal Titin as a Chromosomal Protein

    PubMed Central

    Machado, Cristina; Sunkel, Claudio E.; Andrew, Deborah J.

    1998-01-01

    Assembly of the higher-order structure of mitotic chromosomes is a prerequisite for proper chromosome condensation, segregation and integrity. Understanding the details of this process has been limited because very few proteins involved in the assembly of chromosome structure have been discovered. Using a human autoimmune scleroderma serum that identifies a chromosomal protein in human cells and Drosophila embryos, we cloned the corresponding Drosophila gene that encodes the homologue of vertebrate titin based on protein size, sequence similarity, developmental expression and subcellular localization. Titin is a giant sarcomeric protein responsible for the elasticity of striated muscle that may also function as a molecular scaffold for myofibrillar assembly. Molecular analysis and immunostaining with antibodies to multiple titin epitopes indicates that the chromosomal and muscle forms of titin may vary in their NH2 termini. The identification of titin as a chromosomal component provides a molecular basis for chromosome structure and elasticity. PMID:9548712

  14. Centromere pairing precedes meiotic chromosome pairing in plants.

    PubMed

    Zhang, Jing; Han, Fangpu

    2017-11-01

    Meiosis is a specialized eukaryotic cell division, in which diploid cells undergo a single round of DNA replication and two rounds of nuclear division to produce haploid gametes. In most eukaryotes, the core events of meiotic prophase I are chromosomal pairing, synapsis and recombination. To ensure accurate chromosomal segregation, homologs have to identify and align along each other at the onset of meiosis. Although much progress has been made in elucidating meiotic processes, information on the mechanisms underlying chromosome pairing is limited in contrast to the meiotic recombination and synapsis events. Recent research in many organisms indicated that centromere interactions during early meiotic prophase facilitate homologous chromosome pairing, and functional centromere is a prerequisite for centromere pairing such as in maize. Here, we summarize the recent achievements of chromosome pairing research on plants and other organisms, and outline centromere interactions, nuclear chromosome orientation, and meiotic cohesin, as main determinants of chromosome pairing in early meiotic prophase.

  15. Meiosis Leads to Pervasive Copy-Number Variation and Distorted Inheritance of Accessory Chromosomes of the Wheat Pathogen Zymoseptoria tritici.

    PubMed

    Fouché, Simone; Plissonneau, Clémence; McDonald, Bruce A; Croll, Daniel

    2018-06-01

    Meiosis is one of the most conserved molecular processes in eukaryotes. The fidelity of pairing and segregation of homologous chromosomes has a major impact on the proper transmission of genetic information. Aberrant chromosomal transmission can have major phenotypic consequences, yet the mechanisms are poorly understood. Fungi are excellent models to investigate processes of chromosomal transmission, because many species have highly polymorphic genomes that include accessory chromosomes. Inheritance of accessory chromosomes is often unstable and chromosomal losses have little impact on fitness. We analyzed chromosomal inheritance in 477 progeny coming from two crosses of the fungal wheat pathogen Zymoseptoria tritici. For this, we developed a high-throughput screening method based on restriction site-associated DNA sequencing that generated dense coverage of genetic markers along each chromosome. We identified rare instances of chromosomal duplications (disomy) in core chromosomes. Accessory chromosomes showed high overall frequencies of disomy. Chromosomal rearrangements were found exclusively on accessory chromosomes and were more frequent than disomy. Accessory chromosomes present in only one of the parents in an analyzed cross were inherited at significantly higher rates than the expected 1:1 segregation ratio. Both the chromosome and the parental background had significant impacts on the rates of disomy, losses, rearrangements, and distorted inheritance. We found that chromosomes with higher sequence similarity and lower repeat content were inherited more faithfully. The large number of rearranged progeny chromosomes identified in this species will enable detailed analyses of the mechanisms underlying chromosomal rearrangement.

  16. Congenital Abnormalities

    MedlinePlus

    ... tube defects. However, there is also a genetic influence to this type of congenital anomaly. Unknown Causes The vast majority of congenital abnormalities have no known cause. This is particularly troubling for parents who plan to have more children, because there is no way to predict if ...

  17. Familial isolated clubfoot is associated with recurrent chromosome 17q23.1q23.2 microduplications containing TBX4.

    PubMed

    Alvarado, David M; Aferol, Hyuliya; McCall, Kevin; Huang, Jason B; Techy, Matthew; Buchan, Jillian; Cady, Janet; Gonzales, Patrick R; Dobbs, Matthew B; Gurnett, Christina A

    2010-07-09

    Clubfoot is a common musculoskeletal birth defect for which few causative genes have been identified. To identify the genes responsible for isolated clubfoot, we screened for genomic copy-number variants with the Affymetrix Genome-wide Human SNP Array 6.0. A recurrent chromosome 17q23.1q23.2 microduplication was identified in 3 of 66 probands with familial isolated clubfoot. The chromosome 17q23.1q23.2 microduplication segregated with autosomal-dominant clubfoot in all three families but with reduced penetrance. Mild short stature was common and one female had developmental hip dysplasia. Subtle skeletal abnormalities consisted of broad and shortened metatarsals and calcanei, small distal tibial epiphyses, and thickened ischia. Several skeletal features were opposite to those described in the reciprocal chromosome 17q23.1q23.2 microdeletion syndrome associated with developmental delay and cardiac and limb abnormalities. Of note, during our study, we also identified a microdeletion at the locus in a sibling pair with isolated clubfoot. The chromosome 17q23.1q23.2 region contains the T-box transcription factor TBX4, a likely target of the bicoid-related transcription factor PITX1 previously implicated in clubfoot etiology. Our result suggests that this chromosome 17q23.1q23.2 microduplication is a relatively common cause of familial isolated clubfoot and provides strong evidence linking clubfoot etiology to abnormal early limb development. Copyright 2010 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  18. The Chromosome 18 Clinical Resource Center.

    PubMed

    Cody, Jannine D; Hasi-Zogaj, Minire; Heard, Patricia; Hill, Annice; Rupert, David; Sebold, Courtney; Soileau, Bridgette; Hale, Daniel E

    2018-05-01

    The Chromosome 18 Clinical Research Center has created a pediatrician-friendly virtual resource center for managing patients with chromosome 18 abnormalities. To date, children with rare chromosome abnormalities have been cared for either symptomatically or palliatively as a reaction to the presenting medical problems. As we enter an era of genomic-informed medicine, we can provide children, even those with individually unique chromosome abnormalities, with proactive medical care and management based on the most contemporary data on their specific genomic change. It is problematic for practicing physicians to obtain and use the emerging data on specific genes because this information is derived from diverse sources (e.g., animal studies, case reports, in vitro explorations) and is often published in sources that are not easily accessible in the clinical setting. The Chromosome 18 Clinical Resource Center remedies this challenging problem by curating and synthesizing the data with clinical implications. The data are collected from our database of over 26 years of natural history and medical data from over 650 individuals with chromosome 18 abnormalities. The resulting management guides and video presentations are a first edition of this collated data specifically oriented to guide clinicians toward the optimization of care for each child. The chromosome 18 data and guides also serve as models for an approach to the management of any individual with a rare chromosome abnormality of which there are over 1,300 born every year in the US alone. © 2018 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals, Inc.

  19. Death by Segregation: Does the Dimension of Racial Segregation Matter?

    PubMed

    Yang, Tse-Chuan; Matthews, Stephen A

    2015-01-01

    The county-level geographic mortality differentials have persisted in the past four decades in the United States (US). Though several socioeconomic factors (e.g., inequality) partially explain this phenomenon, the role of race/ethnic segregation, in general, and the different dimensions of segregation, more specifically, has been underexplored. Focusing on all-cause age-sex standardized US county-level mortality (2004-2008), this study has two substantive goals: (1) to understand whether segregation is a determinant of mortality and if yes, how the relationship between segregation and mortality varies by racial/ethnic dyads (e.g., white/black), and (2) to explore whether different dimensions of segregation (i.e., evenness, exposure, concentration, centralization, and clustering) are associated with mortality. A third goal is methodological: to assess whether spatial autocorrelation influences our understanding of the associations between the dimensions of segregation and mortality. Race/ethnic segregation was found to contribute to the geographic mortality disparities. Moreover, the relationship with mortality differed by both race/ethnic group and the dimension of segregation. Specifically, white/black segregation is positively related to mortality, whereas the segregation between whites and non-black minorities is negatively associated with mortality. Among the five dimensions of segregation, evenness and exposure are more strongly related to mortality than other dimensions. Spatial filtering approaches also identified six unique spatial patterns that significantly affect the spatial distribution of mortality. These patterns offer possible insights that help identify omitted variables related to the persistent patterning of mortality in the US.

  20. Maternal uniparental disomy of chromosome 14 in a boy with t(14q14q) associated with a paternal t(13q14q)

    SciTech Connect

    Tomkins, D.J.; Waye, J.S.; Whelan, D.T.

    An 11-year-old boy was referred for chromosomal analysis because of precocious development and behavioral problems suggestive of the fragile X syndrome. The cytogenetic fragile X studies were normal, but a routine GTG-banded karyotype revealed an abnormal male karyotype with a Robertsonian translocation between the two chromosome 14`s: 46,XY,t(14q14q). Paternal karyotyping revealed another abnormal karyotype: 46,XY,t(13q14q). A brother had the same karyotype as the father; the mother was deceased. In order to determine if the apparently balanced t(14q14q) in the proband might be the cause of the clinical findings, molecular analysis of the origin of the chromosome 14`s was initiated. Southernmore » blotting and hybridization with D4S13 showed that the proband had two copies of one maternal allele which was shared by his brother. The brother`s second allele corresponded to one of the paternal alleles; the proband had no alleles from the father. Analysis of four other VNTRs demonstrated the probability of paternity to be greater than 99%. Thus, the t(14q14q) was most likely composed of two maternal chromosome 14`s. Further characterization of the t(14q14q) by dinucleotide repeat polymorphic markers is in progress to determine whether it has arisen from maternal isodisomy or heterodisomy. Several cases of uniparental disomy for chromosome 14 have been reported recently. Paternal disomy appears to be associated with more severe congenital anomalies and mental retardation, whereas maternal disomy may be associated with premature puberty and minimal intellectual impairment. The origin of the t(14q14q) in the present case may be related to the paternal translocation, as the segregation of the t(13q14q) in meiosis could lead to sperm that are nullisomic for chromosome 14.« less

  1. Amplifications of chromosomal region 20q13 as a prognostic indicator in breast cancer

    DOEpatents

    Gray, Joe W.; Collins, Colin; Pinkel, Daniel; Kallioniemi, Olli-Pekka; Tanner, Minna M.

    1998-01-01

    The present invention relates to in situ hybridization methods for the identification of new chromosomal abnormalities associated with various diseases. In particular, it provides probes which are specific to a region of amplification in chromosome 20.

  2. Amplifications of chromosomal region 20q13 as a prognostic indicator breast cancer

    DOEpatents

    Gray, Joe W.; Collins, Colin; Pinkel, Daniel; Kallioniemi, Olli-Pekka; Tanner, Minna M.

    2001-01-01

    The present invention relates to in situ hybridization methods for the identification of new chromosomal abnormalities associated with various diseases. In particular, it provides probes which are specific to a region of amplification in chromosome 20.

  3. Chromosome Analysis

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Perceptive Scientific Instruments, Inc., provides the foundation for the Powergene line of chromosome analysis and molecular genetic instrumentation. This product employs image processing technology from NASA's Jet Propulsion Laboratory and image enhancement techniques from Johnson Space Center. Originally developed to send pictures back to earth from space probes, digital imaging techniques have been developed and refined for use in a variety of medical applications, including diagnosis of disease.

  4. Compositions for chromosome-specific staining

    DOEpatents

    Gray, Joe W.; Pinkel, Daniel

    1998-01-01

    Methods and compositions for staining based upon nucleic acid sequence that employ nucleic acid probes are provided. Said methods produce staining patterns that can be tailored for specific cytogenetic analyses. Said probes are appropriate for in situ hybridization and stain both interphase and metaphase chromosomal material with reliable signals. The nucleic acid probes are typically of a complexity greater than 50 kb, the complexity depending upon the cytogenetic application. Methods are provided to disable the hybridization capacity of shared, high copy repetitive sequences and/or remove such sequences to provide for useful contrast. Still further methods are provided to produce chromosome-specific staining reagents which are made specific to the targeted chromosomal material, which can be one or more whole chromosomes, one or more regions on one or more chromosomes, subsets of chromosomes and/or the entire genome. Probes and test kits are provided for use in tumor cytogenetics, in the detection of disease related loci, in analysis of structural abnormalities, such as translocations, and for biological dosimetry. Further, methods and prenatal test kits are provided to stain targeted chromosomal material of fetal cells, including fetal cells obtained from maternal blood. Still further, the invention provides for automated means to detect and analyse chromosomal abnormalities.

  5. Compositions for chromosome-specific staining

    DOEpatents

    Gray, J.W.; Pinkel, D.

    1998-05-26

    Methods and compositions for staining based upon nucleic acid sequence that employ nucleic acid probes are provided. The methods produce staining patterns that can be tailored for specific cytogenetic analyses. The probes are appropriate for in situ hybridization and stain both interphase and metaphase chromosomal material with reliable signals. The nucleic acid probes are typically of a complexity greater than 50 kb, the complexity depending upon the cytogenetic application. Methods are provided to disable the hybridization capacity of shared, high copy repetitive sequences and/or remove such sequences to provide for useful contrast. Still further methods are provided to produce chromosome-specific staining reagents which are made specific to the targeted chromosomal material, which can be one or more whole chromosomes, one or more regions on one or more chromosomes, subsets of chromosomes and/or the entire genome. Probes and test kits are provided for use in tumor cytogenetics, in the detection of disease related loci, in analysis of structural abnormalities, such as translocations, and for biological dosimetry. Methods and prenatal test kits are provided to stain targeted chromosomal material of fetal cells, including fetal cells obtained from maternal blood. The invention provides for automated means to detect and analyze chromosomal abnormalities. 17 figs.

  6. A Regulatory Switch Alters Chromosome Motions at the Metaphase to Anaphase Transition

    PubMed Central

    Su, Kuan-Chung; Barry, Zachary; Schweizer, Nina; Maiato, Helder; Bathe, Mark; Cheeseman, Iain McPherson

    2016-01-01

    Summary To achieve chromosome segregation during mitosis, sister chromatids must undergo a dramatic change in their behavior to switch from balanced oscillations at the metaphase plate to directed poleward motion during anaphase. However, the factors that alter chromosome behavior at the metaphase-to-anaphase transition remain incompletely understood. Here, we perform time-lapse imaging to analyze anaphase chromosome dynamics in human cells. Using multiple directed biochemical, genetic, and physical perturbations, our results demonstrate that differences in the global phosphorylation states between metaphase and anaphase are the major determinant of chromosome motion dynamics. Indeed, causing a mitotic phosphorylation state to persist into anaphase produces dramatic metaphase-like oscillations. These induced oscillations depend on both kinetochore-derived and polar ejection forces that oppose poleward motion. Thus, our analysis of anaphase chromosome motion reveals that dephosphorylation of multiple mitotic substrates is required to suppress metaphase chromosome oscillatory motions and achieve directed poleward motion for successful chromosome segregation. PMID:27829144

  7. Neo-sex chromosome inheritance across species in Silene hybrids.

    PubMed

    Weingartner, L A; Delph, L F

    2014-07-01

    Neo-sex chromosomes, which form through the major restructuring of ancestral sex chromosome systems, have evolved in various taxa. Such restructuring often consists of the fusion of an autosome to an existing sex chromosome, resulting in novel sex chromosome formations (e.g. X1X2Y or XY1Y2.). Comparative studies are often made between restructured sex chromosome systems of closely related species, and here we evaluate the consequences of variable sex chromosome systems to hybrids. If neo-sex chromosomes are improperly inherited across species, this could lead to aberrant development and reproductive isolation. In this study, we examine the fate of neo-sex chromosomes in hybrids of the flowering plants Silene diclinis and Silene latifolia. Silene diclinis has a neo-sex chromosome system (XY1Y2) that is thought to have evolved from an ancestral XY system that is still present in S. latifolia. These species do not hybridize naturally, and improper sex chromosome inheritance could contribute to reproductive isolation. We investigated whether this major restructuring of sex chromosomes prevents their proper inheritance in a variety of hybrid crosses, including some F2 - and later-generation hybrids, with sex chromosome-linked, species-specific, polymorphic markers and chromosome squashes. We discovered that despite the differences in sex chromosomes that exist between these two species, proper segregation had occurred in hybrids that made it to flowering, including later-generation hybrids, indicating that neo-sex chromosome formation alone does not result in complete reproductive isolation between these two species. Additionally, hybrids with aberrant sex expression (e.g. neuter, hermaphrodite) also inherited the restructured sex chromosomes properly, highlighting that issues with sexual development in hybrids can be caused by intrinsic genetic incompatibility rather than improper sex chromosome inheritance. © 2014 The Authors. Journal of Evolutionary Biology © 2014

  8. Replication-dependent and independent mechanisms for the chromosome-coupled persistence of a selfish genome

    PubMed Central

    Liu, Yen-Ting; Chang, Keng-Ming; Ma, Chien-Hui; Jayaram, Makkuni

    2016-01-01

    The yeast 2-micron plasmid epitomizes the evolutionary optimization of selfish extra-chromosomal genomes for stable persistence without jeopardizing their hosts’ fitness. Analyses of fluorescence-tagged single-copy reporter plasmids and/or the plasmid partitioning proteins in native and non-native hosts reveal chromosome-hitchhiking as the likely means for plasmid segregation. The contribution of the partitioning system to equal segregation is bipartite- replication-independent and replication-dependent. The former nearly eliminates ‘mother bias’ (preferential plasmid retention in the mother cell) according to binomial distribution, thus limiting equal segregation of a plasmid pair to 50%. The latter enhances equal segregation of plasmid sisters beyond this level, elevating the plasmid close to chromosome status. Host factors involved in plasmid partitioning can be functionally separated by their participation in the replication-independent and/or replication-dependent steps. In the hitchhiking model, random tethering of a pair of plasmids to chromosomes signifies the replication-independent component of segregation; the symmetric tethering of plasmid sisters to sister chromatids embodies the replication-dependent component. The 2-micron circle broadly resembles the episomes of certain mammalian viruses in its chromosome-associated propagation. This unifying feature among otherwise widely differing selfish genomes suggests their evolutionary convergence to the common logic of exploiting, albeit via distinct molecular mechanisms, host chromosome segregation machineries for self-preservation. PMID:27492289

  9. Replication-dependent and independent mechanisms for the chromosome-coupled persistence of a selfish genome.

    PubMed

    Liu, Yen-Ting; Chang, Keng-Ming; Ma, Chien-Hui; Jayaram, Makkuni

    2016-09-30

    The yeast 2-micron plasmid epitomizes the evolutionary optimization of selfish extra-chromosomal genomes for stable persistence without jeopardizing their hosts' fitness. Analyses of fluorescence-tagged single-copy reporter plasmids and/or the plasmid partitioning proteins in native and non-native hosts reveal chromosome-hitchhiking as the likely means for plasmid segregation. The contribution of the partitioning system to equal segregation is bipartite- replication-independent and replication-dependent. The former nearly eliminates 'mother bias' (preferential plasmid retention in the mother cell) according to binomial distribution, thus limiting equal segregation of a plasmid pair to 50%. The latter enhances equal segregation of plasmid sisters beyond this level, elevating the plasmid close to chromosome status. Host factors involved in plasmid partitioning can be functionally separated by their participation in the replication-independent and/or replication-dependent steps. In the hitchhiking model, random tethering of a pair of plasmids to chromosomes signifies the replication-independent component of segregation; the symmetric tethering of plasmid sisters to sister chromatids embodies the replication-dependent component. The 2-micron circle broadly resembles the episomes of certain mammalian viruses in its chromosome-associated propagation. This unifying feature among otherwise widely differing selfish genomes suggests their evolutionary convergence to the common logic of exploiting, albeit via distinct molecular mechanisms, host chromosome segregation machineries for self-preservation. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  10. Regelation and ice segregation

    NASA Technical Reports Server (NTRS)

    Miller, Robert D.

    1988-01-01

    Macroscopic processes can have an important effect on the state of regolith water. The two primary mechanisms responsible for the formation of segregated ice on Earth, thermally induced regelation and hydraulic fracturing, are reviewed while their potential importance on Mars is examined. While regelation is the dominant terrestrial process, it requires a warmer and wetter environment than currently exists on Mars. In this respect, the conditions required for hydraulic fracturing are less demanding. In assessing its potential importance on Mars, it is noted that hydraulic fracturing can produce a localized zone of high pressure water that could readily disrupt an overburden of frozen ground. Such a process, it is concluded, may have triggered the release of groundwater that led to the formation of the major outflow channels.

  11. Chiasmatic and achiasmatic inverted meiosis of plants with holocentric chromosomes

    PubMed Central

    Cabral, Gabriela; Marques, André; Schubert, Veit; Pedrosa-Harand, Andrea; Schlögelhofer, Peter

    2014-01-01

    Meiosis is a specialized cell division in sexually reproducing organisms before gamete formation. Following DNA replication, the canonical sequence in species with monocentric chromosomes is characterized by reductional segregation of homologous chromosomes during the first and equational segregation of sister chromatids during the second meiotic division. Species with holocentric chromosomes employ specific adaptations to ensure regular disjunction during meiosis. Here we present the analysis of two closely related plant species with holocentric chromosomes that display an inversion of the canonical meiotic sequence, with the equational division preceding the reductional. In-depth analysis of the meiotic divisions of Rhynchospora pubera and R. tenuis reveals that during meiosis I sister chromatids are bi-oriented, display amphitelic attachment to the spindle and are subsequently separated. During prophase II, chromatids are connected by thin chromatin threads that appear instrumental for the regular disjunction of homologous non-sister chromatids in meiosis II. PMID:25295686

  12. Micronucleus formation causes perpetual unilateral chromosome inheritance in mouse embryos

    PubMed Central

    Vázquez-Diez, Cayetana; Yamagata, Kazuo; Trivedi, Shardul; Haverfield, Jenna; FitzHarris, Greg

    2016-01-01

    Chromosome segregation defects in cancer cells lead to encapsulation of chromosomes in micronuclei (MN), small nucleus-like structures within which dangerous DNA rearrangements termed chromothripsis can occur. Here we uncover a strikingly different consequence of MN formation in preimplantation development. We find that chromosomes from within MN become damaged and fail to support a functional kinetochore. MN are therefore not segregated, but are instead inherited by one of the two daughter cells. We find that the same MN can be inherited several times without rejoining the principal nucleus and without altering the kinetics of cell divisions. MN motion is passive, resulting in an even distribution of MN across the first two cell lineages. We propose that perpetual unilateral MN inheritance constitutes an unexpected mode of chromosome missegregation, which could contribute to the high frequency of aneuploid cells in mammalian embryos, but simultaneously may serve to insulate the early embryonic genome from chromothripsis. PMID:26729872

  13. Micronucleus formation causes perpetual unilateral chromosome inheritance in mouse embryos.

    PubMed

    Vázquez-Diez, Cayetana; Yamagata, Kazuo; Trivedi, Shardul; Haverfield, Jenna; FitzHarris, Greg

    2016-01-19

    Chromosome segregation defects in cancer cells lead to encapsulation of chromosomes in micronuclei (MN), small nucleus-like structures within which dangerous DNA rearrangements termed chromothripsis can occur. Here we uncover a strikingly different consequence of MN formation in preimplantation development. We find that chromosomes from within MN become damaged and fail to support a functional kinetochore. MN are therefore not segregated, but are instead inherited by one of the two daughter cells. We find that the same MN can be inherited several times without rejoining the principal nucleus and without altering the kinetics of cell divisions. MN motion is passive, resulting in an even distribution of MN across the first two cell lineages. We propose that perpetual unilateral MN inheritance constitutes an unexpected mode of chromosome missegregation, which could contribute to the high frequency of aneuploid cells in mammalian embryos, but simultaneously may serve to insulate the early embryonic genome from chromothripsis.

  14. The genetic basis of developmental abnormalities in interpopulation hybrids of the moss Ceratodon purpureus.

    PubMed

    McDaniel, Stuart F; Willis, John H; Shaw, A Jonathan

    2008-07-01

    Divergent populations are intrinsically reproductively isolated when hybrids between them either fail to develop properly or do not produce viable offspring. Intrinsic isolation may result from Dobzhansky-Muller (DM) incompatibilities, in which deleterious interactions among genes or gene products lead to developmental problems or underdominant chromosome structure differences between the parents. These mechanisms can be tested by studying marker segregation patterns in a hybrid mapping population. Here we examine the genetic basis of abnormal development in hybrids between two geographically distant populations of the moss Ceratodon purpureus. Approximately half of the hybrid progeny exhibited a severely reduced growth rate in early gametophyte development. We identified four unlinked quantitative trait loci (QTL) that interacted asymmetrically to cause the abnormal development phenotype. This pattern is consistent with DM interactions. We also found an excess of recombination between three marker pairs in the abnormally developing progeny, relative to that estimated in the normal progeny. This suggests that structural differences in these regions contribute to hybrid breakdown. Two QTL coincided with inferred structural differences, consistent with recent theory suggesting that rearrangements may harbor population divergence alleles. These observations suggest that multiple complex genetic factors contribute to divergence among populations of C. purpureus.

  15. Exposure of spermatozoa to dibutyl phthalate induces abnormal embryonic development in a marine invertebrate Galeolaria caespitosa (Polychaeta: Serpulidae).

    PubMed

    Lu, Yonggang; Lin, Minjie; Aitken, Robert John

    2017-10-01

    In this study, we have investigated the impact of dibutyl phthalate (DBP) on early embryogenesis in a sessile marine invertebrate, Galeolaria caespitosa. DBP was found to induce sperm dysfunction as well as impaired and defective embryogenesis characterised by a particular pattern of abnormality. Thus, after the first cleavage, one blastomere in these abnormal embryos was able to carry out further mitoses, while the other arrested. Analysis of microtubules, chromosomes and actin filaments demonstrated that the mitotic spindles in the abnormal embryos were irregularly bent, shortened and unable to anchor to the cortex, resulting in the defective segregation of chromosomes. Within the non-dividing blastomeres, karyokinesis was found to continue at a slow pace as indicated by the presence of multiple sets of abnormal mitotic spindles. However, cytokinesis had been disrupted in these arrested cells due to a failure to assemble the contractile actin ring, as a result of which one pole of the embryos remained as one large, undivided cell. DBP was found to suppress the activity of superoxide dismutase in spermatozoa and, in association with this change, DBP-treated cells experienced oxidative stress as indicated by the presence of lipid aldehydes, such as 4-hydroxynonenal (4-HNE) in the sperm acrosome and neck. Adduction of lipid aldehydes at the level of the acrosome would be expected to impede the acrosome reaction and account for the significant decrease in fertilisation rates. 4-HNE generated as a consequence of lipid peroxidation in the sperm neck resulted in alkylation of the sperm centrioles. Such paternally damaged centrioles were inherited by the embryos and disrupted cytoskeletal protein organisation during early cleavage, generating the observed abnormalities in embryonic development. This research emphasises the vulnerability of spermatozoa to oxidative damage and highlights novel potential mechanisms for reproductive toxicity involving the alkylation of

  16. A Demonstration of Sample Segregation

    ERIC Educational Resources Information Center

    Fritz, Mark D.; Brumbach, Stephen B.; Hartman, JudithAnn R.

    2005-01-01

    The demonstration of sample segregation, which is simple, and visually compelling illustrates the importance of sample handling for students studying analytical chemistry and environmental chemistry. The mixture used in this demonstration has two components, which have big particle size, and different colors, which makes the segregation graphic.

  17. The Dimensions of Residential Segregation.

    ERIC Educational Resources Information Center

    Massey, Douglas S.; Denton, Nancy A.

    1988-01-01

    Evaluates 20 potential indicators of residential segregation using census data on Hispanics, Blacks, Asians, and non-Hispanic Whites in 60 U.S. metropolitan areas. Factor-analyzes the results to select a single best indicator for each of five dimensions of residential segregation. Contains 69 references and 22 statistical formulas. (SV)

  18. Multilevel Modeling of Social Segregation

    ERIC Educational Resources Information Center

    Leckie, George; Pillinger, Rebecca; Jones, Kelvyn; Goldstein, Harvey

    2012-01-01

    The traditional approach to measuring segregation is based upon descriptive, non-model-based indices. A recently proposed alternative is multilevel modeling. The authors further develop the argument for a multilevel modeling approach by first describing and expanding upon its notable advantages, which include an ability to model segregation at a…

  19. PinX1 is recruited to the mitotic chromosome periphery by Nucleolin and facilitates chromosome congression.

    PubMed

    Li, Na; Yuan, Kai; Yan, Feng; Huo, Yuda; Zhu, Tongge; Liu, Xing; Guo, Zhen; Yao, Xuebiao

    2009-06-19

    Mitotic chromosome movements are orchestrated by interactions between spindle microtubules and chromosomes. It is well known that kinetochore is the major site where microtubule-chromosome attachment occurs. However, the functions of other domains of chromosome such as chromosome periphery have remained elusive. Our previous studies show that PinX1 distributes to chromosome periphery and kinetochore during mitosis, and harbors the microtubule binding activity. Here we report that PinX1 interacts with Nucleolin, a chromosome periphery protein, through its C-termini. Deconvolution microscopic analyses show PinX1 mainly co-localizes with Nucleolin at chromosome periphery in prometaphase. Moreover, depletion of Nucleolin abolishes chromosome periphery localizations of PinX1, suggesting a functional interrelationship between PinX1 and Nucleolin. Importantly, repression of PinX1 and Nucleolin abrogates chromosome segregation in real-time mitosis, validating the functional importance of PinX1-Nucleolin interaction. We propose PinX1 is recruited to chromosome periphery by Nucleolin and a complex of PinX1 and Nucleolin is essential for faithful chromosome congression.

  20. Chromosomal disorders and male infertility

    PubMed Central

    Harton, Gary L; Tempest, Helen G

    2012-01-01

    Infertility in humans is surprisingly common occurring in approximately 15% of the population wishing to start a family. Despite this, the molecular and genetic factors underlying the cause of infertility remain largely undiscovered. Nevertheless, more and more genetic factors associated with infertility are being identified. This review will focus on our current understanding of the chromosomal basis of male infertility specifically: chromosomal aneuploidy, structural and numerical karyotype abnormalities and Y chromosomal microdeletions. Chromosomal aneuploidy is the leading cause of pregnancy loss and developmental disabilities in humans. Aneuploidy is predominantly maternal in origin, but concerns have been raised regarding the safety of intracytoplasmic sperm injection as infertile men have significantly higher levels of sperm aneuploidy compared to their fertile counterparts. Males with numerical or structural karyotype abnormalities are also at an increased risk of producing aneuploid sperm. Our current understanding of how sperm aneuploidy translates to embryo aneuploidy will be reviewed, as well as the application of preimplantation genetic diagnosis (PGD) in such cases. Clinical recommendations where possible will be made, as well as discussion of the use of emerging array technology in PGD and its potential applications in male infertility. PMID:22120929

  1. Chromosomal disorders and male infertility.

    PubMed

    Harton, Gary L; Tempest, Helen G

    2012-01-01

    Infertility in humans is surprisingly common occurring in approximately 15% of the population wishing to start a family. Despite this, the molecular and genetic factors underlying the cause of infertility remain largely undiscovered. Nevertheless, more and more genetic factors associated with infertility are being identified. This review will focus on our current understanding of the chromosomal basis of male infertility specifically: chromosomal aneuploidy, structural and numerical karyotype abnormalities and Y chromosomal microdeletions. Chromosomal aneuploidy is the leading cause of pregnancy loss and developmental disabilities in humans. Aneuploidy is predominantly maternal in origin, but concerns have been raised regarding the safety of intracytoplasmic sperm injection as infertile men have significantly higher levels of sperm aneuploidy compared to their fertile counterparts. Males with numerical or structural karyotype abnormalities are also at an increased risk of producing aneuploid sperm. Our current understanding of how sperm aneuploidy translates to embryo aneuploidy will be reviewed, as well as the application of preimplantation genetic diagnosis (PGD) in such cases. Clinical recommendations where possible will be made, as well as discussion of the use of emerging array technology in PGD and its potential applications in male infertility.

  2. Chromosome I duplications in Caenorhabditis elegans

    SciTech Connect

    McKim, K.S.; Rose, A.M.

    1990-01-01

    We have isolated and characterized 76 duplications of chromosome I in the genome of Caenorhabditis elegans. The region studied is the 20 map unit left half of the chromosome. Sixty-two duplications were induced with gamma radiation and 14 arose spontaneously. The latter class was apparently the result of spontaneous breaks within the parental duplication. The majority of duplications behave as if they are free. Three duplications are attached to identifiable sequences from other chromosomes. The duplication breakpoints have been mapped by complementation analysis relative to genes on chromosome I. Nineteen duplication breakpoints and seven deficiency breakpoints divide the left halfmore » of the chromosome into 24 regions. We have studied the relationship between duplication size and segregational stability. While size is an important determinant of mitotic stability, it is not the only one. We observed clear exceptions to a size-stability correlation. In addition to size, duplication stability may be influenced by specific sequences or chromosome structure. The majority of the duplications were stable enough to be powerful tools for gene mapping. Therefore the duplications described here will be useful in the genetic characterization of chromosome I and the techniques we have developed can be adapted to other regions of the genome.« less

  3. Mechanisms of Chromosome Congression during Mitosis

    PubMed Central

    Maiato, Helder; Gomes, Ana Margarida; Sousa, Filipe; Barisic, Marin

    2017-01-01

    diversity by means of tubulin post-translational modifications. This so-called “tubulin code” might work as a navigation system that selectively guides kinetochore motors with opposite polarities along specific spindle microtubule populations, ultimately leading to the congression of peripheral chromosomes. We propose an integrated model of chromosome congression in mammalian cells that depends essentially on the following parameters: (1) chromosome position relative to the spindle poles after nuclear envelope breakdown; (2) establishment of stable end-on kinetochore-microtubule attachments and bi-orientation; (3) coordination between kinetochore- and arm-associated motors; and (4) spatial signatures associated with post-translational modifications of specific spindle microtubule populations. The physiological consequences of abnormal chromosome congression, as well as the therapeutic potential of inhibiting chromosome congression are also discussed. PMID:28218637

  4. Abnormal placentation.

    PubMed

    Bauer, Samuel T; Bonanno, Clarissa

    2009-04-01

    Abnormal placentation poses a diagnostic and treatment challenge for all providers caring for pregnant women. As one of the leading causes of postpartum hemorrhage, abnormal placentation involves the attachment of placental villi directly to the myometrium with potentially deeper invasion into the uterine wall or surrounding organs. Surgical procedures that disrupt the integrity of uterus, including cesarean section, dilatation and curettage, and myomectomy, have been implicated as key risk factors for placenta accreta. The diagnosis is typically made by gray-scale ultrasound and confirmed with magnetic resonance imaging, which may better delineate the extent of placental invasion. It is critical to make the diagnosis before delivery because preoperative planning can significantly decrease blood loss and avoid substantial morbidity associated with placenta accreta. Aggressive management of hemorrhage through the use of uterotonics, fluid resuscitation, blood products, planned hysterectomy, and surgical hemostatic agents can be life-saving for these patients. Conservative management, including the use of uterine and placental preservation and subsequent methotrexate therapy or pelvic artery embolization, may be considered when a focal accreta is suspected; however, surgical management remains the current standard of care.

  5. Exceptional complex chromosomal rearrangements in three generations.

    PubMed

    Kartapradja, Hannie; Marzuki, Nanis Sacharina; Pertile, Mark D; Francis, David; Suciati, Lita Putri; Anggaratri, Helena Woro; Ambarwati, Debby Dwi; Idris, Firman Prathama; Lesmana, Harry; Trimarsanto, Hidayat; Paramayuda, Chrysantine; Harahap, Alida Roswita

    2015-01-01

    We report an exceptional complex chromosomal rearrangement (CCR) found in three individuals in a family that involves 4 chromosomes with 5 breakpoints. The CCR was ascertained in a phenotypically abnormal newborn with additional chromosomal material on the short arm of chromosome 4. Maternal karyotyping indicated that the mother carried an apparently balanced CCR involving chromosomes 4, 6, 11, and 18. Maternal transmission of the derivative chromosome 4 resulted in partial trisomy for chromosomes 6q and 18q and a partial monosomy of chromosome 4p in the proband. Further family studies found that the maternal grandmother carried the same apparently balanced CCR as the proband's mother, which was confirmed using the whole chromosome painting (WCP) FISH. High resolution whole genome microarray analysis of DNA from the proband's mother found no evidence for copy number imbalance in the vicinity of the CCR translocation breakpoints, or elsewhere in the genome, providing evidence that the mother's and grandmother's CCRs were balanced at a molecular level. This structural rearrangement can be categorized as an exceptional CCR due to its complexity and is a rare example of an exceptional CCR being transmitted in balanced and/or unbalanced form across three generations.

  6. Linkage group-chromosome correlations in Sordaria macrospora: Chromosome identification by three dimensional reconstruction of their synaptonemal complex.

    PubMed

    Zickler, D; Leblon, G; Haedens, V; Collard, A; Thuriaux, P

    1984-01-01

    Reconstruction of serially sectioned zygotene and pachytene nuclei has allowed, by measuring the lengths of synaptonemal complexes, an assignment of the 7 linkage (LG) groups to the 7 chromosomes in the fungus Sordaria macrospora. The 7 LG have been established using 19 mutants showing low second division segregation frequencies. Eight chromosomal rearrangements mapped on the 7 LG were used to identify the chromosomes involved. The following one to one assignment of the 7 LG to specific chromosomes was obtained: LG a: chromosome (chr) 1, LG b: chr5, LG c: chr6, LG d: chr7, LG e: chr4, LG f: chr3 and LG g: chr2 (the chromosome carrying the nucleolus organizer region).

  7. Chromosome behaviour in Rhoeo spathacea var. variegata.

    PubMed

    Lin, Y J

    1980-01-01

    Rhoeo spathacea var. variegata is unusual in that its twelve chromosomes are arranged in a ring at meiosis. The order of the chromosomes has been established, and each chromosome arm has been designated a letter in accordance with the segmental interchange theory. Chromosomes are often irregularly orientated at metaphase I. Chromosomes at anaphase I are generally distributed equally (6-6, 58.75%) although not necessarily balanced. Due to adjacent distribution, 7-5 distribution at anaphase I was frequently observed (24.17%), and due to lagging, 6-1-5 and 5-2-5 distributions were also observed (10.83% and 3.33% respectively). Three types of abnormal distribution, 8-4, 7-1-4 and 6-2-4 were observed very infrequently (2.92% total), and their possible origins are discussed. Irregularities, such as adjacent distribution and lagging, undoubtedly reduce the fertility of the plant because of the resulting unbalanced gametes.

  8. Pericentric Inversion of Chromosome 9 in an Infant With Ambiguous Genitalia.

    PubMed

    Sotoudeh, Arya; Rostami, Parastoo; Nakhaeimoghadam, Maryam; Mohsenipour, Reihaneh; Rezaei, Nima

    2017-10-01

    Pericentric inversion of Chromosome 9 is one of the most common chromosomal abnormalities, which could be associated with various manifestations in some cases. Herein, a patient is presented with ambiguous genitalia that karyotyping revealed pericentric inversion of Chromosome 9 (p12,q13). Pericentric inversion of Chromosome 9 could be considered in the list of differential diagnosis of those with ambiguous genitalia, while chromosomal karyotype and culture could be recommended in children with ambiguous genitalia.

  9. Asymmetric segregation of template DNA strands in basal-like human breast cancer cell lines

    PubMed Central

    2013-01-01

    Background and methods Stem or progenitor cells from healthy tissues have the capacity to co-segregate their template DNA strands during mitosis. Here, we set out to test whether breast cancer cell lines also possess the ability to asymmetrically segregate their template DNA strands via non-random chromosome co-segregation, and whether this ability correlates with certain properties attributed to breast cancer stem cells (CSCs). We quantified the frequency of asymmetric segregation of template DNA strands in 12 human breast cancer cell lines, and correlated the frequency to molecular subtype, CD44+/CD24-/lo phenotype, and invasion/migration ability. We tested if co-culture with human mesenchymal stem cells, which are known to increase self-renewal, can alter the frequency of asymmetric segregation of template DNA in breast cancer. Results We found a positive correlation between asymmetric segregation of template DNA and the breast cancer basal-like and claudin-low subtypes. There was an inverse correlation between asymmetric segregation of template DNA and Her2 expression. Breast cancer samples with evidence of asymmetric segregation of template DNA had significantly increased invasion and borderline significantly increased migration abilities. Samples with high CD44+/CD24-/lo surface expression were more likely to harbor a consistent population of cells that asymmetrically segregated its template DNA; however, symmetric self-renewal was enriched in the CD44+/CD24-/lo population. Co-culturing breast cancer cells with human mesenchymal stem cells expanded the breast CSC pool and decreased the frequency of asymmetric segregation of template DNA. Conclusions Breast cancer cells within the basal-like subtype can asymmetrically segregate their template DNA strands through non-random chromosome segregation. The frequency of asymmetric segregation of template DNA can be modulated by external factors that influence expansion or self-renewal of CSC populations. Future

  10. School Desegregation and Residential Segregation.

    ERIC Educational Resources Information Center

    Billingsley, Andrew; And Others

    1979-01-01

    This statement on school and residential segregation, signed by 38 educators and social scientists, was prepared for attorneys connected with litigation concerning the Dayton and Columbus school systems. (RLV)

  11. Aplastic Anemia in Two Patients with Sex Chromosome Aneuploidies.

    PubMed

    Rush, Eric T; Schaefer, G Bradley; Sanger, Warren G; Coccia, Peter F

    2015-01-01

    Sex chromosome aneuploidies range in incidence from rather common to exceedingly rare and have a variable phenotype. We report 2 patients with sex chromosome aneuploidies who developed severe aplastic anemia requiring treatment. The first patient had tetrasomy X (48,XXXX) and presented at 9 years of age, and the second patient had trisomy X (47,XXX) and presented at 5 years of age. Although aplastic anemia has been associated with other chromosomal abnormalities, sex chromosome abnormalities have not been traditionally considered a risk factor for this condition. A review of the literature reveals that at least one other patient with a sex chromosome aneuploidy (45,X) has suffered from aplastic anemia and that other autosomal chromosomal anomalies have been described. Despite the uncommon nature of each condition, it is possible that the apparent association is coincidental. A better understanding of the genetic causes of aplastic anemia remains important. © 2015 S. Karger AG, Basel.

  12. Novel Chromosome Organization Pattern in Actinomycetales—Overlapping Replication Cycles Combined with Diploidy

    PubMed Central

    Böhm, Kati; Meyer, Fabian; Rhomberg, Agata; Kalinowski, Jörn; Donovan, Catriona

    2017-01-01

    ABSTRACT Bacteria regulate chromosome replication and segregation tightly with cell division to ensure faithful segregation of DNA to daughter generations. The underlying mechanisms have been addressed in several model species. It became apparent that bacteria have evolved quite different strategies to regulate DNA segregation and chromosomal organization. We have investigated here how the actinobacterium Corynebacterium glutamicum organizes chromosome segregation and DNA replication. Unexpectedly, we found that C. glutamicum cells are at least diploid under all of the conditions tested and that these organisms have overlapping C periods during replication, with both origins initiating replication simultaneously. On the basis of experimental data, we propose growth rate-dependent cell cycle models for C. glutamicum. PMID:28588128

  13. Surface Segregation in Ternary Alloys

    NASA Technical Reports Server (NTRS)

    Good, Brian; Bozzolo, Guillermo H.; Abel, Phillip B.

    2000-01-01

    Surface segregation profiles of binary (Cu-Ni, Au-Ni, Cu-Au) and ternary (Cu-Au-Ni) alloys are determined via Monte Carlo-Metropolis computer simulations using the BFS method for alloys for the calculation of the energetics. The behavior of Cu or Au in Ni is contrasted with their behavior when both are present. The interaction between Cu and Au and its effect on the segregation profiles for Cu-Au-Ni alloys is discussed.

  14. Mapping of the bcl-2 oncogene on mouse chromosome 1.

    PubMed

    Mock, B A; Givol, D; D'Hoostelaere, L A; Huppi, K; Seldin, M F; Gurfinkel, N; Unger, T; Potter, M; Mushinski, J F

    1988-01-01

    Two bcl-2 alleles have been identified in inbred strains of mice by restriction fragment length polymorphism (RFLP). Analysis of a bcl-2 RFLP in a series of bilineal congenic strains (C.D2), developed as a tool for chromosomal mapping studies, revealed linkage of bcl-2 to the Idh-1/Pep-3 region of murine chromosome 1. The co-segregation of bcl-2 alleles with allelic forms of two other chromosome 1 loci, Ren-1,2 and Spna-1, in a set of back-cross progeny, positions bcl-2 7.8 cM centromeric from Ren-1,2.

  15. Relationships between chromosome structure and chromosomal aberrations

    NASA Astrophysics Data System (ADS)

    Eidelman, Yuri; Andreev, Sergey

    An interphase nucleus of human lymphocyte was simulated by the novel Monte Carlo tech-nique. The main features of interphase chromosome structure and packaging were taken into account: different levels of chromatin organisation; nonrandom localisation of chromosomes within a nucleus; chromosome loci dynamics. All chromosomes in a nucleus were modelled as polymer globules. A dynamic pattern of intra/interchromosomal contacts was simulated. The detailed information about chromosomal contacts, such as distribution of intrachromoso-mal contacts over the length of each chromosome and dependence of contact probability on genomic separation between chromosome loci, were calculated and compared to the new exper-imental data obtained by the Hi-C technique. Types and frequencies of simple and complex radiation-induced chromosomal exchange aberrations (CA) induced by X-rays were predicted with taking formation and decay of chromosomal contacts into account. Distance dependence of exchange formation probability was calculated directly. mFISH data for human lymphocytes were analysed. The calculated frequencies of simple CA agreed with the experimental data. Complex CA were underestimated despite the dense packaging of chromosome territories within a nucleus. Possible influence of chromosome-nucleus structural organisation on the frequency and spectrum of radiation-induced chromosome aberrations is discussed.

  16. A Revaluation of Indexes of Residential Segregation

    ERIC Educational Resources Information Center

    Winship, Christopher

    1977-01-01

    Shows that there are at least two different perspectives from which residential segregation can be examined. Segregation can be measured as it deviates from a situation of complete desegregation or in terms of a situation in which there is random segregation in the city. New criteria for indexes of residential segregation are developed. (Author/JM)

  17. Income Segregation between Schools and School Districts

    ERIC Educational Resources Information Center

    Owens, Ann; Reardon, Sean F.; Jencks, Christopher

    2016-01-01

    Although trends in the racial segregation of schools are well documented, less is known about trends in income segregation. We use multiple data sources to document trends in income segregation between schools and school districts. Between-district income segregation of families with children enrolled in public school increased by over 15% from…

  18. Higher 5-hydroxymethylcytosine identifies immortal DNA strand chromosomes in asymmetrically self-renewing distributed stem cells

    PubMed Central

    Huh, Yang Hoon; Cohen, Justin; Sherley, James L.

    2013-01-01

    Immortal strands are the targeted chromosomal DNA strands of nonrandom sister chromatid segregation, a mitotic chromosome segregation pattern unique to asymmetrically self-renewing distributed stem cells (DSCs). By nonrandom segregation, immortal DNA strands become the oldest DNA strands in asymmetrically self-renewing DSCs. Nonrandom segregation of immortal DNA strands may limit DSC mutagenesis, preserve DSC fate, and contribute to DSC aging. The mechanisms responsible for specification and maintenance of immortal DNA strands are unknown. To discover clues to these mechanisms, we investigated the 5-methylcytosine and 5-hydroxymethylcytosine (5hmC) content on chromosomes in mouse hair follicle DSCs during nonrandom segregation. Although 5-methylcytosine content did not differ significantly, the relative content of 5hmC was significantly higher in chromosomes containing immortal DNA strands than in opposed mitotic chromosomes containing younger mortal DNA strands. The difference in relative 5hmC content was caused by the loss of 5hmC from mortal chromosomes. These findings implicate higher 5hmC as a specific molecular determinant of immortal DNA strand chromosomes. Because 5hmC is an intermediate during DNA demethylation, we propose a ten-eleven translocase enzyme mechanism for both the specification and maintenance of nonrandomly segregated immortal DNA strands. The proposed mechanism reveals a means by which DSCs “know” the generational age of immortal DNA strands. The mechanism is supported by molecular expression data and accounts for the selection of newly replicated DNA strands when nonrandom segregation is initiated. These mechanistic insights also provide a possible basis for another characteristic property of immortal DNA strands, their guanine ribonucleotide dependency. PMID:24082118

  19. Higher 5-hydroxymethylcytosine identifies immortal DNA strand chromosomes in asymmetrically self-renewing distributed stem cells.

    PubMed

    Huh, Yang Hoon; Cohen, Justin; Sherley, James L

    2013-10-15

    Immortal strands are the targeted chromosomal DNA strands of nonrandom sister chromatid segregation, a mitotic chromosome segregation pattern unique to asymmetrically self-renewing distributed stem cells (DSCs). By nonrandom segregation, immortal DNA strands become the oldest DNA strands in asymmetrically self-renewing DSCs. Nonrandom segregation of immortal DNA strands may limit DSC mutagenesis, preserve DSC fate, and contribute to DSC aging. The mechanisms responsible for specification and maintenance of immortal DNA strands are unknown. To discover clues to these mechanisms, we investigated the 5-methylcytosine and 5-hydroxymethylcytosine (5hmC) content on chromosomes in mouse hair follicle DSCs during nonrandom segregation. Although 5-methylcytosine content did not differ significantly, the relative content of 5hmC was significantly higher in chromosomes containing immortal DNA strands than in opposed mitotic chromosomes containing younger mortal DNA strands. The difference in relative 5hmC content was caused by the loss of 5hmC from mortal chromosomes. These findings implicate higher 5hmC as a specific molecular determinant of immortal DNA strand chromosomes. Because 5hmC is an intermediate during DNA demethylation, we propose a ten-eleven translocase enzyme mechanism for both the specification and maintenance of nonrandomly segregated immortal DNA strands. The proposed mechanism reveals a means by which DSCs "know" the generational age of immortal DNA strands. The mechanism is supported by molecular expression data and accounts for the selection of newly replicated DNA strands when nonrandom segregation is initiated. These mechanistic insights also provide a possible basis for another characteristic property of immortal DNA strands, their guanine ribonucleotide dependency.

  20. Segregation and Poverty Concentration: The Role of Three Segregations

    PubMed Central

    Quillian, Lincoln

    2014-01-01

    A key argument of Massey and Denton’s American Apartheid (1993) is that racial residential segregation and non-white group poverty rates combine interactively to produce spatially concentrated poverty. Despite a compelling theoretical rationale, the empirical tests of this proposition have been negative or mixed. This paper develops a formal decomposition model that expands the Massey model of how segregation, group poverty rates, and other spatial conditions combine to form concentrated poverty. The revised decomposition model allows for income effects on cross-race neighborhood residence and interactive combinations of multiple spatial conditions in the formation of concentrated poverty. Applying the model to data reveals that racial segregation and income segregation within race contribute importantly to poverty concentration, as Massey argued, but that almost equally important for poverty concentration is the disproportionate poverty of the non-group neighbors of blacks and Hispanics. The missing interaction Massey expected in empirical tests can be found with proper accounting for the factors in the expanded model. “Because of racial segregation, a significant share of black America is condemned to experience a social environment where poverty and joblessness are the norm, where a majority of children are born out of wedlock, where most families are on welfare, where educational failure prevails, and where social and physical deterioration abound. Through prolonged exposure to such an environment, black chances for social and economic success are drastically reduced.”--Douglas Massey and Nancy Denton, American Apartheid, p. 2 PMID:24648570

  1. Prevalence of chromosomal aberrations in Mexican women with primary amenorrhoea.

    PubMed

    Cortés-Gutiérrez, Elva I; Dávila-Rodríguez, Martha I; Vargas-Villarreal, Javier; Cerda-Flores, Ricardo M

    2007-10-01

    Primary amenorrhoea refers to the absence of menarche by the age of 16-18 years in the presence of secondary sexual characteristics, and occurs in 1-3% of women of reproductive age. To study the prevalence of chromosomal abnormalities and the different options available for clinical management of women in Mexico with primary amenorrhoea, a cross-sectional study was conducted in 187 women with primary amenorrhoea referred from Department of Reproductive Medicine of Morones Prieto Hospital, IMSS in Monterrey, Mexico during 1995-2003. Peripheral blood lymphocytes were cultured for chromosomal studies by the standard methods. Numerical or structural abnormalities of the sex chromosome were found in 78 women (41.71%). These women were classified into four categories: X-chromosome aneuploidies (22.99%: 12.83% pure line and 10.16% mosaicism association with a 45, X cell line); presence of chromosome Y (10.70%); structural anomalies of the X chromosome (4.28%); and marker chromosomes (3.74%). In conclusion, the prevalence of chromosomal abnormalities in Mexican women with primary amenorrhoea is within the range (24-46%) reported in world literature. Chromosomal analysis is absolutely necessary for appropriate clinical management of these patients.

  2. APC/C Dysfunction Limits Excessive Cancer Chromosomal Instability

    PubMed Central

    Sansregret, Laurent; López-García, Carlos; Koch, André; McGranahan, Nicholas; Chao, William Chong Hang; Barry, David J.; Rowan, Andrew; Instrell, Rachael; Horswell, Stuart; Way, Michael; Howell, Michael; Singleton, Martin R.; Medema, René H.; Nurse, Paul; Petronczki, Mark; Swanton, Charles

    2017-01-01

    Intercellular heterogeneity, exacerbated by chromosomal instability (CIN), fosters tumor heterogeneity and drug resistance. However, extreme CIN correlates with improved cancer outcome, suggesting that karyotypic diversity required to adapt to selection pressures might be balanced in tumors against the risk of excessive instability. Here, we used a functional genomics screen, genome editing, and pharmacologic approaches to identify CIN-survival factors in diploid cells. We find partial anaphase-promoting complex/cyclosome (APC/C) dysfunction lengthens mitosis, suppresses pharmacologically induced chromosome segregation errors, and reduces naturally occurring lagging chromosomes in cancer cell lines or following tetraploidization. APC/C impairment caused adaptation to MPS1 inhibitors, revealing a likely resistance mechanism to therapies targeting the spindle assembly checkpoint. Finally, CRISPR-mediated introduction of cancer somatic mutations in the APC/C subunit cancer driver gene CDC27 reduces chromosome segregation errors, whereas reversal of an APC/C subunit nonsense mutation increases CIN. Subtle variations in mitotic duration, determined by APC/C activity, influence the extent of CIN, allowing cancer cells to dynamically optimize fitness during tumor evolution. Significance We report a mechanism whereby cancers balance the evolutionary advantages associated with CIN against the fitness costs caused by excessive genome instability, providing insight into the consequence of CDC27 APC/C subunit driver mutations in cancer. Lengthening of mitosis through APC/C modulation may be a common mechanism of resistance to cancer therapeutics that increase chromosome segregation errors. PMID:28069571

  3. Protective role of RAD50 on chromatin bridges during abnormal cytokinesis.

    PubMed

    Schröder-Heurich, Bianca; Wieland, Britta; Lavin, Martin F; Schindler, Detlev; Dörk, Thilo

    2014-03-01

    Faithful chromosome segregation is required for preserving genomic integrity. Failure of this process may entail chromatin bridges preventing normal cytokinesis. To test whether RAD50, a protein normally involved in DNA double-strand break repair, is involved in abnormal cytokinesis and formation of chromatin bridges, we used immunocytochemical and protein interaction assays. RAD50 localizes to chromatin bridges during aberrant cytokinesis and subsequent stages of the cell cycle, either decorating the entire bridge or focally accumulating at the midbody zone. Ionizing radiation led to an ∼4-fold increase in the rate of chromatin bridges in an ataxia telangiectatica mutated (ATM)-dependent manner in human RAD50-proficient fibroblasts but not in RAD50-deficient cells. Cells with a RAD50-positive chromatin bridge were able to continue cell cycling and to progress through S phase (44%), whereas RAD50 knockdown caused a deficiency in chromatin bridges as well as an ∼4-fold prolonged duration of mitosis. RAD50 colocalized and directly interacted with Aurora B kinase and phospho-histone H3, and Aurora B kinase inhibition led to a deficiency in RAD50-positive bridges. Based on these observations, we propose that RAD50 is a crucial factor for the stabilization and shielding of chromatin bridges. Our study provides evidence for a hitherto unknown role of RAD50 in abnormal cytokinesis.

  4. Philadelphia Chromosome Symposium: commemoration of the 50th anniversary of the discovery of the Ph chromosome

    PubMed Central

    Chandra, H. Sharat; Heistekamp, Nora C.; Hungerford, Alice; Morrissette, Jennifer J.D.; Nowell, Peter C.; Rowley, Janet D.; Testa, Joseph R.

    2011-01-01

    This report summarizes highlights of the ‘Philadelphia Chromosome Symposium: Past, Present and Future’, held September 28, 2010, to commemorate the 50th anniversary of the discovery of the Philadelphia chromosome. The symposium sessions included presentations by investigators who made seminal contributions concerning the discovery and molecular characterization of the Ph chromosome and others who developed a highly successful therapy based on the specific molecular alteration observed in chronic myelogenous leukemia. Additional presentations highlighted future opportunities for the design of molecularly targeted therapies for various types of cancer. Also included here are reminiscences connected with the discovery of the Ph chromosome by David Hungerford and Peter Nowell, the discovery that the abnormality arises from a chromosomal translocation, by Janet Rowley, and the cloning of the 9;22 translocation breakpoints by Nora Heisterkamp, John Groffen and colleagues. PMID:21536234

  5. Centromere inactivation on a neo-Y fusion chromosome in threespine stickleback fish

    PubMed Central

    Cech, Jennifer N.; Peichel, Catherine L.

    2016-01-01

    Having one and only one centromere per chromosome is essential for proper chromosome segregation during both mitosis and meiosis. Chromosomes containing two centromeres are known as dicentric and often mis-segregate during cell division, resulting in aneuploidy or chromosome breakage. Dicentric chromosome can be stabilized by centromere inactivation, a process which re-establishes monocentric chromosomes. However, little is known about this process in naturally occurring dicentric chromosomes. Using a combination of fluorescence in situ hybridization (FISH) and immunoflourescence combined with FISH (IF-FISH) on metaphase chromosome spreads, we demonstrate that centromere inactivation has evolved on a neo-Y chromosome fusion in the Japan Sea threespine stickleback fish (Gasterosteus nipponicus). We found that the centromere derived from the ancestral Y chromosome has been inactivated. Our data further suggest that there have been genetic changes to this centromere in the two million years since the formation of the neo-Y chromosome, but it remains unclear whether these genetic changes are a cause or consequence of centromere inactivation. PMID:27553478

  6. Segregation for fertility and meiotic stability in novel Brassica allohexaploids.

    PubMed

    Mwathi, Margaret W; Gupta, Mehak; Atri, Chaya; Banga, Surinder S; Batley, Jacqueline; Mason, Annaliese S

    2017-04-01

    Allohexaploid Brassica populations reveal ongoing segregation for fertility, while genotype influences fertility and meiotic stability. Creation of a new Brassica allohexaploid species is of interest for the development of a crop type with increased heterosis and adaptability. At present, no naturally occurring, meiotically stable Brassica allohexaploid exists, with little data available on chromosome behaviour and meiotic control in allohexaploid germplasm. In this study, 100 plants from the cross B. carinata × B. rapa (A2 allohexaploid population) and 69 plants from the cross (B. napus × B. carinata) × B. juncea (H2 allohexaploid population) were assessed for fertility and meiotic behaviour. Estimated pollen viability, self-pollinated seed set, number of seeds on the main shoot, number of pods on the main shoot, seeds per ten pods and plant height were measured for both the A2 and H2 populations and for a set of reference control cultivars. The H2 population had high segregation for pollen viability and meiotic stability, while the A2 population was characterised by low pollen fertility and a high level of chromosome loss. Both populations were taller, but had lower average fertility trait values than the control cultivar samples. The study also characterises fertility and meiotic chromosome behaviour in genotypes and progeny sets in heterozygous allotetraploid Brassica derived lines, and indicates that genotypes of the parents and H1 hybrids are affecting chromosome pairing and fertility phenotypes in the H2 population. The identification and characterisation of factors influencing stability in novel allohexaploid Brassica populations will assist in the development of this as a new crop species for food and agricultural benefit.

  7. Dosage Compensation of the Sex Chromosomes

    PubMed Central

    Disteche, Christine M.

    2013-01-01

    Differentiated sex chromosomes evolved because of suppressed recombination once sex became genetically controlled. In XX/XY and ZZ/ZW systems, the heterogametic sex became partially aneuploid after degeneration of the Y or W. Often, aneuploidy causes abnormal levels of gene expression throughout the entire genome. Dosage compensation mechanisms evolved to restore balanced expression of the genome. These mechanisms include upregulation of the heterogametic chromosome as well as repression in the homogametic sex. Remarkably, strategies for dosage compensation differ between species. In organisms where more is known about molecular mechanisms of dosage compensation, specific protein complexes containing noncoding RNAs are targeted to the X chromosome. In addition, the dosage-regulated chromosome often occupies a specific nuclear compartment. Some genes escape dosage compensation, potentially resulting in sex-specific differences in gene expression. This review focuses on dosage compensation in mammals, with comparisons to fruit flies, nematodes, and birds. PMID:22974302

  8. A patient with familial bone marrow failure and an inversion of chromosome 8.

    PubMed

    Buchbinder, David Kyle; Zadeh, Touran; Nugent, Diane

    2011-12-01

    Familial bone marrow failure has been associated with a variety of chromosomal aberrations. Chromosome 8 abnormalities have been described in association with neoplastic and hematologic disorders; however, to our knowledge, inversion of the long arm of chromosome 8 has not been described in the context of familial bone marrow failure. We describe a 9-year-old female with familial bone marrow failure and an inversion of chromosome 8 [inv (8) (q22, q24.3)]. Given the importance of considering the genetic determinants of familial bone marrow failure, the potential role of chromosome 8 abnormalities in the development of marrow failure is discussed.

  9. DNA and origin region segregation are not affected by the transition from rod to sphere after inhibition of Escherichia coli MreB by A22.

    PubMed

    Karczmarek, Aneta; Martínez-Arteaga, Rocío; Baselga, Rocío Martínez-Arteaga; Alexeeva, Svetlana; Hansen, Flemming G; Vicente, Miguel; Nanninga, Nanne; den Blaauwen, Tanneke

    2007-07-01

    The bacterial actin homologue MreB forms a helix underneath the cytoplasmic membrane and was shown to be essential in the morphogenesis of the rod-shaped cells. Additionally, MreB was implicated to be involved in DNA segregation. However, in our hands the mreBCD deletion strain (PA340-678) grew without apparent DNA segregation defect, suggesting that the reported chromosome segregation inhibition could be caused by a temporarily effect of MreB inhibition or depletion. To assess the involvement of MreB in DNA segregation during the transition from rod to sphere, we compared the effect of A22 and the PBP2 inhibitor mecillinam on the percentage of cells with segregated nucleoids and the number of oriC foci in wild-type Escherichia coli cells. Cells became spherical in the same time window during both treatments and we could not detect any difference in the chromosome or oriC segregation between these two treatments. Additionally, flow cytometric analyses showed that A22 and mecillinam treatment gave essentially the same chromosome segregation pattern. We conclude that MreB is not directly involved in DNA segregation of E. coli.

  10. Quantitative analysis of chromosome condensation in fission yeast.

    PubMed

    Petrova, Boryana; Dehler, Sascha; Kruitwagen, Tom; Hériché, Jean-Karim; Miura, Kota; Haering, Christian H

    2013-03-01

    Chromosomes undergo extensive conformational rearrangements in preparation for their segregation during cell divisions. Insights into the molecular mechanisms behind this still poorly understood condensation process require the development of new approaches to quantitatively assess chromosome formation in vivo. In this study, we present a live-cell microscopy-based chromosome condensation assay in the fission yeast Schizosaccharomyces pombe. By automatically tracking the three-dimensional distance changes between fluorescently marked chromosome loci at high temporal and spatial resolution, we analyze chromosome condensation during mitosis and meiosis and deduct defined parameters to describe condensation dynamics. We demonstrate that this method can determine the contributions of condensin, topoisomerase II, and Aurora kinase to mitotic chromosome condensation. We furthermore show that the assay can identify proteins required for mitotic chromosome formation de novo by isolating mutants in condensin, DNA polymerase ε, and F-box DNA helicase I that are specifically defective in pro-/metaphase condensation. Thus, the chromosome condensation assay provides a direct and sensitive system for the discovery and characterization of components of the chromosome condensation machinery in a genetically tractable eukaryote.

  11. Quantitative Analysis of Chromosome Condensation in Fission Yeast

    PubMed Central

    Petrova, Boryana; Dehler, Sascha; Kruitwagen, Tom; Hériché, Jean-Karim; Miura, Kota

    2013-01-01

    Chromosomes undergo extensive conformational rearrangements in preparation for their segregation during cell divisions. Insights into the molecular mechanisms behind this still poorly understood condensation process require the development of new approaches to quantitatively assess chromosome formation in vivo. In this study, we present a live-cell microscopy-based chromosome condensation assay in the fission yeast Schizosaccharomyces pombe. By automatically tracking the three-dimensional distance changes between fluorescently marked chromosome loci at high temporal and spatial resolution, we analyze chromosome condensation during mitosis and meiosis and deduct defined parameters to describe condensation dynamics. We demonstrate that this method can determine the contributions of condensin, topoisomerase II, and Aurora kinase to mitotic chromosome condensation. We furthermore show that the assay can identify proteins required for mitotic chromosome formation de novo by isolating mutants in condensin, DNA polymerase ε, and F-box DNA helicase I that are specifically defective in pro-/metaphase condensation. Thus, the chromosome condensation assay provides a direct and sensitive system for the discovery and characterization of components of the chromosome condensation machinery in a genetically tractable eukaryote. PMID:23263988

  12. Complex and Dynamic Chromosomal Rearrangements in a Family With Seemingly Non-Mendelian Inheritance of Dopa-Responsive Dystonia.

    PubMed

    Lohmann, Katja; Redin, Claire; Tönnies, Holger; Bressman, Susan B; Subero, Jose Ignacio Martin; Wiegers, Karin; Hinrichs, Frauke; Hellenbroich, Yorck; Rakovic, Aleksandar; Raymond, Deborah; Ozelius, Laurie J; Schwinger, Eberhard; Siebert, Reiner; Talkowski, Michael E; Saunders-Pullman, Rachel; Klein, Christine

    2017-07-01

    Chromosomal rearrangements are increasingly recognized to underlie neurologic disorders and are often accompanied by additional clinical signs beyond the gene-specific phenotypic spectrum. To elucidate the causal genetic variant in a large US family with co-occurrence of dopa-responsive dystonia as well as skeletal and eye abnormalities (ie, ptosis, myopia, and retina detachment). We examined 10 members of a family, including 5 patients with dopa-responsive dystonia and skeletal and/or eye abnormalities, from a US tertiary referral center for neurological diseases using multiple conventional molecular methods, including fluorescence in situ hybridization and array comparative genomic hybridization as well as large-insert whole-genome sequencing to survey multiple classes of genomic variations. Of note, there was a seemingly implausible transmission pattern in this family due to a mutation-negative obligate mutation carrier. Genetic diagnosis in affected family members and insight into the formation of large deletions. Four members were diagnosed with definite and 1 with probable dopa-responsive dystonia. All 5 affected individuals carried a large heterozygous deletion encompassing all 6 exons of GCH1. Additionally, all mutation carriers had congenital ptosis requiring surgery, 4 had myopia, 2 had retinal detachment, and 2 showed skeletal abnormalities of the hands, ie, polydactyly or syndactyly or missing a hand digit. Two individuals were reported to be free of any disease. Analyses revealed complex chromosomal rearrangements on chromosome 14q21-22 in unaffected individuals that triggered the expansion to a larger deletion segregating with affection status. The expansion occurred recurrently, explaining the seemingly non-mendelian inheritance pattern. These rearrangements included a deletion of GCH1, which likely contributes to the dopa-responsive dystonia, as well as a deletion of BMP4 as a potential cause of digital and eye abnormalities. Our findings alert

  13. Relationship of Chromosome Changes to Neoplastic Cell Transformation

    PubMed Central

    DiPaolo, Joseph A.; Popescu, Nicolae C.

    1976-01-01

    Chromosomal abnormalities are a frequent concomitant of neoplasia, and although it is tempting to relate these mutations and alterations in chromatin (DNA) function to cancer, their relationship to the initiation or progression of carcinogenesis is unknown. Mammalian cells in culture, after interacting with chemical carcinogens, often exhibit chromosome damage consisting of breaks and exchanges of chromatid material. The pattern of damage of banded metaphases indicates that negative bands are especially vulnerable to the action of chemical carcinogens, probably because of differential chromatin condensation. Damage to individual chromosomes may be random or nonrandom, depending on the species. Cell death can be correlated with chromatid alterations that occur shortly after treatment with chemical carcinogens. There is also a correlation between mutagenic and carcinogenic activity of some chemical carcinogens and the frequency of sister chromatid exchanges. The question of whether specific chromosome changes are absolutely required for neoplastic transformation cannot be answered because of conflicting data and diverse results from studies even with known carcinogens. Cell transformation may occur without any visible chromosome changes. A universal specific numerical or visible structural chromosomal alteration is not necessarily associated with chemical or viral transformation. Chromosome changes are independent of the etiologic agents: different carcinogens may produce transformation associated with the same abnormal chromosomes, but not all transformed lines invariably exhibit the same abnormality, even with the same chemical. In some species, chromosome having nucleolar organizer regions may be more frequently involved in numerical or structural deviations. Progressively growing tumors also may occur as a result of the proliferation of transformed cells without detectable chromosome changes, indicating that tumorigenicity need not be related to an imbalance of

  14. Segregated Schools in Segregated Societies: Issues of Safety and Risk

    ERIC Educational Resources Information Center

    Leonard, Madeleine

    2006-01-01

    In segregated societies such as Northern Ireland, schools may become sites of risk rather than sites of learning. This is particularly likely to be the case in interface areas, which are demarcated by peace-lines and other symbolic boundaries. Drawing on maps and focus group discussions with teenagers from interface areas in North Belfast, the…

  15. Assessment of aneuploidy in human oocytes and preimplantation embryos by chromosome painting

    SciTech Connect

    Rougier, N.; Viegas-Pequignot, E.; Plachot, M.

    1994-09-01

    The poor quality of chromosome preparations often observed after fixation of oocytes and embryos did not usually allow accurate identification of chromosomes involved in non-disjunctions. We, therefore, used chromosome painting to determine the incidence of abnormalities for chromosomes 1 and 7. A total of 50 oocytes inseminated for IVF and showing no signs of fertilization as well as 37 diploid embryos donated for research were fixed according to the Dyban`s technique. Fluorescence in situ hybridization was carried out using whole chromosome painting DNA probes specific for human chromosome 1 and 7. The incidence of aneuploidy was 28%, 10% and 60%more » for metaphase II, polar body and sperm chromosomes, respectively. The high incidence of aneuploidy observed in sperm prematurely condensed sperm chromosomes is due to the fact that usually far less than 23 sperm chromatids are observed, maybe as a consequence of incomplete chromosome condensation. Thirty seven embryos were analyzed with the same probes. 48% of early embryos were either monosomic 1 or 7 or mosaics comprising blastomeres with 1, 2 or 3 signals. Thus, 8 among the 11 abnormal embryos had hypodiploid cells (25 to 37 chromosomes) indicating either an artefactual loss of chromosomes or a complex anomaly of nuclear division (maltinucleated blastomeres, abnormal migration of chromosomes at anaphase). We therefore calculated a {open_quotes}corrected{close_quotes} incidence of aneuploidy for chromosomes 1 or 7 in early embryos: 18%. 86% of the blastocysts showed mosaicism 2n/3 or 4n as a consequence of the formation of the syncitiotrophoblast. To conclude, chromosome painting is an efficient method to accurately identify chromosomes involved in aneuploidy. This technique should allow us to evaluate the incidence of non-disjunction for all chromosome pairs. Our results confirm the high incidence of chromosome abnormalities occurring as a consequence of meiotic or mitotic non-disjunctions in human oocytes and

  16. Magnetic resonance imaging abnormalities in familial temporal lobe epilepsy with auditory auras.

    PubMed

    Kobayashi, Eliane; Santos, Neide F; Torres, Fabio R; Secolin, Rodrigo; Sardinha, Luiz A C; Lopez-Cendes, Iscia; Cendes, Fernando

    2003-11-01

    Two forms of familial temporal lobe epilepsy (FTLE) have been described: mesial FTLE and FTLE with auditory auras. The gene responsible for mesial FTLE has not been mapped yet, whereas mutations in the LGI1 (leucine-rich, glioma-inactivated 1) gene, localized on chromosome 10q, have been found in FTLE with auditory auras. To describe magnetic resonance imaging (MRI) findings in patients with FTLE with auditory auras. We performed detailed clinical and molecular studies as well as MRI evaluation (including volumetry) in all available individuals from one family, segregating FTLE from auditory auras. We evaluated 18 of 23 possibly affected individuals, and 13 patients reported auditory auras. In one patient, auditory auras were associated with déjà vu; in one patient, with ictal aphasia; and in 2 patients, with visual misperception. Most patients were not taking medication at the time, although all of them reported sporadic auras. Two-point lod scores were positive for 7 genotyped markers on chromosome 10q, and a Zmax of 6.35 was achieved with marker D10S185 at a recombination fraction of 0.0. Nucleotide sequence analysis of the LGI1 gene showed a point mutation, VIIIS7(-2)A-G, in all affected individuals. Magnetic resonance imaging was performed in 22 individuals (7 asymptomatic, 4 of them carriers of the affected haplotype on chromosome 10q and the VIIIS7[-2]A-G mutation). Lateral temporal lobe malformations were identified by visual analysis in 10 individuals, 2 of them with global enlargement demonstrated by volumetry. Mildly reduced hippocampi were observed in 4 individuals. In this family with FTLE with auditory auras, we found developmental abnormalities in the lateral cortex of the temporal lobes in 53% of the affected individuals. In contrast with mesial FTLE, none of the affected individuals had MRI evidence of hippocampal sclerosis.

  17. Undetected sex chromosome aneuploidy by chromosomal microarray.

    PubMed

    Markus-Bustani, Keren; Yaron, Yuval; Goldstein, Myriam; Orr-Urtreger, Avi; Ben-Shachar, Shay

    2012-11-01

    We report on a case of a female fetus found to be mosaic for Turner syndrome (45,X) and trisomy X (47,XXX). Chromosomal microarray analysis (CMA) failed to detect the aneuploidy because of a normal average dosage of the X chromosome. This case represents an unusual instance in which CMA may not detect chromosomal aberrations. Such a possibility should be taken into consideration in similar cases where CMA is used in a clinical setting. © 2012 John Wiley & Sons, Ltd.

  18. [Strategies to identify supernumerary chromosomal markers in constitutional cytogenetics].

    PubMed

    Douet-Guilbert, N; Basinko, A; Le Bris, M-J; Herry, A; Morel, F; De Braekeleer, M

    2008-09-01

    Supernumerary marker chromosomes (SMCs) are defined as extrastructurally abnormal chromosomes which origin and composition cannot be determined by conventional cytogenetics. SMCs are an heterogeneous group of abnormalities concerning all chromosomes with variable structure and size and are associated with phenotypic heterogeneity. The characterisation of SMCs is of utmost importance for genetic counselling. Different molecular techniques are used to identify chromosomal material present in markers such as 24-colour FISH (MFISH, SKY), centromere specific multicolour FISH (cenMFISH) and derivatives (acroMFISH, subcenMFISH), comparative genomic hybridisation (CGH), arrayCGH, and targeted FISH techniques (banding techniques, whole chromosome painting...). Based on the morphology of SMC with conventional cytogenetic and clinical data, we tried to set up different molecular strategies with all available techniques.

  19. Dicentric chromosomes: unique models to study centromere function and inactivation.

    PubMed

    Stimpson, Kaitlin M; Matheny, Justyne E; Sullivan, Beth A

    2012-07-01

    Dicentric chromosomes are products of genome rearrangement that place two centromeres on the same chromosome. Depending on the organism, dicentric stability varies after formation. In humans, dicentrics occur naturally in a substantial portion of the population and usually segregate successfully in mitosis and meiosis. Their stability has been attributed to inactivation of one of the two centromeres, creating a functionally monocentric chromosome that can segregate normally during cell division. The molecular basis for centromere inactivation is not well understood, although studies in model organisms and in humans suggest that genomic and epigenetic mechanisms can be involved. Furthermore, constitutional dicentric chromosomes ascertained in patients presumably represent the most stable chromosomes, so the spectrum of dicentric fates, if it exists, is not entirely clear. Studies of engineered or induced dicentrics in budding yeast and plants have provided significant insight into the fate of dicentric chromosomes. And, more recently, studies have shown that dicentrics in humans can also undergo multiple fates after formation. Here, we discuss current experimental evidence from various organisms that has deepened our understanding of dicentric behavior and the intriguingly complex process of centromere inactivation.

  20. Dicentric chromosomes: unique models to study centromere function and inactivation

    PubMed Central

    Stimpson, Kaitlin M.; Matheny, Justyne E.

    2013-01-01

    Dicentric chromosomes are products of genome rearrangement that place two centromeres on the same chromosome. Depending on the organism, dicentric stability varies after formation. In humans, dicentrics occur naturally in a substantial portion of the population and usually segregate successfully in mitosis and meiosis. Their stability has been attributed to inactivation of one of the two centromeres, creating a functionally monocentric chromosome that can segregate normally during cell division. The molecular basis for centromere inactivation is not well under-stood, although studies in model organisms and in humans suggest that genomic and epigenetic mechanisms can be involved. Furthermore, constitutional dicentric chromosomes ascertained in patients presumably represent the most stable chromosomes, so the spectrum of dicentric fates, if it exists, is not entirely clear. Studies of engineered or induced dicentrics in budding yeast and plants have provided significant insight into the fate of dicentric chromosomes. And, more recently, studies have shown that dicentrics in humans can also undergo multiple fates after formation. Here, we discuss current experimental evidence from various organisms that has deepened our understanding of dicentric behavior and the intriguingly complex process of centromere inactivation. PMID:22801777

  1. Meiotic Nuclear Oscillations Are Necessary to Avoid Excessive Chromosome Associations.

    PubMed

    Chacón, Mariola R; Delivani, Petrina; Tolić, Iva M

    2016-11-01

    Pairing of homologous chromosomes is a crucial step in meiosis, which in fission yeast depends on nuclear oscillations. However, how nuclear oscillations help pairing is unknown. Here, we show that homologous loci typically pair when the spindle pole body is at the cell pole and the nucleus is elongated, whereas they unpair when the spindle pole body is in the cell center and the nucleus is round. Inhibition of oscillations demonstrated that movement is required for initial pairing and that prolonged association of loci leads to mis-segregation. The double-strand break marker Rec25 accumulates in elongated nuclei, indicating that prolonged chromosome stretching triggers recombinatory pathways leading to mis-segregation. Mis-segregation is rescued by overexpression of the Holliday junction resolvase Mus81, suggesting that prolonged pairing results in irresolvable recombination intermediates. We conclude that nuclear oscillations exhibit a dual role, promoting initial pairing and restricting the time of chromosome associations to ensure proper segregation. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  2. Lack of response to unaligned chromosomes in mammalian female gametes

    PubMed Central

    Sebestova, Jaroslava; Danylevska, Anna; Novakova, Lucia; Kubelka, Michal; Anger, Martin

    2012-01-01

    Chromosome segregation errors are highly frequent in mammalian female meiosis, and their incidence gradually increases with maternal age. The fate of aneuploid eggs is obviously dependent on the stringency of mechanisms for detecting unattached or repairing incorrectly attached kinetochores. In case of their failure, the newly formed embryo will inherit the impaired set of chromosomes, which will have severe consequences for its further development. Whether spindle assembly checkpoint (SAC) in oocytes is capable of arresting cell cycle progression in response to unaligned kinetochores was discussed for a long time. It is known that abolishing SAC increases frequency of chromosome segregation errors and causes precocious entry into anaphase; SAC, therefore, seems to be essential for normal chromosome segregation in meiosis I. However, it was also reported that for anaphase-promoting complex (APC) activation, which is a prerequisite for entering anaphase; alignment of only a critical mass of kinetochores on equatorial plane is sufficient. This indicates that the function of SAC and of cooperating chromosome attachment correction mechanisms in oocytes is different from somatic cells. To analyze this phenomenon, we used live cell confocal microscopy to monitor chromosome movements, spindle formation, APC activation and polar body extrusion (PBE) simultaneously in individual oocytes at various time points during first meiotic division. Our results, using oocytes from aged animals and interspecific crosses, demonstrate that multiple unaligned kinetochores and severe congression defects are tolerated at the metaphase to anaphase transition, although such cells retain sensitivity to nocodazole. This indicates that checkpoint mechanisms, operating in oocytes at this point, are essential for accurate timing of APC activation in meiosis I, but they are insufficient in detection or correction of unaligned chromosomes, preparing thus conditions for propagation of the aneuploidy

  3. Integration in a Segregated Society.

    ERIC Educational Resources Information Center

    Rothstein, Stanley William

    1979-01-01

    At the end of two decades of integration efforts, America's urban schools have been completely re-segregated by White flight to the suburbs, and our nation is still blighted by a deep-seated segregationist mentality among Whites who continue to dread contact with the Black and the poor. (Author/SJL)

  4. Why Our Schools Are Segregated

    ERIC Educational Resources Information Center

    Rothstein, Richard

    2013-01-01

    "Residential segregation's causes are both knowable and known," writes Richard Rothstein. According to Rothstein, those causes are "20th century federal, state, and local policies explicitly designed to separate the races." Even seasoned policymakers are convinced that the residential isolation of low-income black children is…

  5. Gender Segregation: Separate but Effective?

    ERIC Educational Resources Information Center

    Holthouse, David

    2010-01-01

    In 2002, only 11 public schools in the United States had gender-segregated classrooms. As of December 2009, there were more than 550. The movement is based on the hypothesis that hard-wired differences in the ways that male and female brains develop and function in childhood through adolescence require classrooms in which boys and girls are not…

  6. Abnormal Uterine Bleeding FAQ

    MedlinePlus

    ... Abnormal Uterine Bleeding • What is a normal menstrual cycle? • When is bleeding abnormal? • At what ages is ... abnormal bleeding? •Glossary What is a normal menstrual cycle? The normal length of the menstrual cycle is ...

  7. Abnormal Uterine Bleeding

    MedlinePlus

    ... abnormal uterine bleeding? Abnormal uterine bleeding is any heavy or unusual bleeding from the uterus (through your ... one symptom of abnormal uterine bleeding. Having extremely heavy bleeding during your period can also be considered ...

  8. Segregation effects during solidification in weightless melts

    NASA Technical Reports Server (NTRS)

    Li, C.

    1973-01-01

    Two types of melt segregation effects were studied: (1) evaporative segregation, or segregation due to surface evaporation; and (2) freezing segregation, or segregation due to liquid-solid phase transformation. These segregation effects are closely related. In fact, evaporative segregation always precedes freezing segregation to some degree and must often be studied prior to performing meaningful solidification experiments. This is particularly true since evaporation may cause the melt composition, at least at the critical surface regions or layers to be affected manyfold within seconds so that the surface region or layer melting point and other thermophysical properties, nucleation characteristics, base for undercooling, and critical velocity to avoid constitutional supercooling, may be completely unexpected. An important objective was, therefore, to develop the necessary normal evaporation equations for predicting the compositional changes within specified times at temperature and to correlate these equations with actual experimental data collected from the literature.

  9. The Segregation Academy and the Law

    ERIC Educational Resources Information Center

    Champagne, Anthony M.

    1973-01-01

    A case study of one private school which functions as a segregation academy'' was done in order to learn more about what segregation academies are, how they operate, and how they relate to the community. (Author/JM)

  10. Chromosome Disorder Outreach

    MedlinePlus

    ... Chromosome Disorder Outreach, Inc is a non-profit organization. Founded, supported, and run by parents just like ... Chromosome Disorder Outreach, Inc, a 501c non-profit organization. CDO is a 501C3 non-profit organization. FL ...

  11. The Big Disconnect between Segregation and Integration

    ERIC Educational Resources Information Center

    Verdun, Vincene

    2005-01-01

    The hearts and minds of the American people have been won over on the issue of segregation. However, the dilemma is that while an overwhelming majority of Americans would cringe at the idea of a racially segregated America, America remains racially segregated and racial equality is more ideal than real. Even though there is almost no legal…

  12. 36 CFR 254.6 - Segregative effect.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Segregative effect. 254.6... ADJUSTMENTS Land Exchanges § 254.6 Segregative effect. (a) If a proposal is made to exchange Federal lands... segregative effect terminates as follows: (1) Automatically, upon issuance of a patent or other document of...

  13. 18 CFR 401.113 - Segregable materials.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Segregable materials. 401.113 Section 401.113 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION... Segregable materials. Any reasonably segregable portion of a record shall be provided to any person...

  14. 18 CFR 401.113 - Segregable materials.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Segregable materials. 401.113 Section 401.113 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION... Segregable materials. Any reasonably segregable portion of a record shall be provided to any person...

  15. 18 CFR 401.113 - Segregable materials.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Segregable materials. 401.113 Section 401.113 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION... Segregable materials. Any reasonably segregable portion of a record shall be provided to any person...

  16. 18 CFR 401.113 - Segregable materials.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 2 2012-04-01 2012-04-01 false Segregable materials. 401.113 Section 401.113 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION... Segregable materials. Any reasonably segregable portion of a record shall be provided to any person...

  17. 49 CFR 176.708 - Segregation distances.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Segregation distances. 176.708 Section 176.708... Requirements for Radioactive Materials § 176.708 Segregation distances. (a) Table IV lists minimum separation... into account any relocation of cargo during the voyage. (e) Any departure from the segregation...

  18. 43 CFR 2091.2-1 - Segregation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Segregation. 2091.2-1 Section 2091.2-1..., DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) SPECIAL LAWS AND RULES Segregation and Opening of Lands § 2091.2-1 Segregation. The publication of a Notice of Realty Action in the Federal Register...

  19. Mps1 and Ipl1/Aurora B act sequentially to correctly orient chromosomes on the meiotic spindle of budding yeast.

    PubMed

    Meyer, Régis E; Kim, Seoyoung; Obeso, David; Straight, Paul D; Winey, Mark; Dawson, Dean S

    2013-03-01

    The conserved kinases Mps1 and Ipl1/Aurora B are critical for enabling chromosomes to attach to microtubules so that partner chromosomes will be segregated correctly from each other, but the precise roles of these kinases have been unclear. We imaged live yeast cells to elucidate the stages of chromosome-microtubule interactions and their regulation by Ipl1 and Mps1 through meiosis I. Ipl1 was found to release kinetochore-microtubule (kMT) associations after meiotic entry, liberating chromosomes to begin homologous pairing. Surprisingly, most chromosome pairs began their spindle interactions with incorrect kMT attachments. Ipl1 released these improper connections, whereas Mps1 triggered the formation of new force-generating microtubule attachments. This microtubule release and reattachment cycle could prevent catastrophic chromosome segregation errors in meiosis.

  20. Centromere Destiny in Dicentric Chromosomes: New Insights from the Evolution of Human Chromosome 2 Ancestral Centromeric Region.

    PubMed

    Chiatante, Giorgia; Giannuzzi, Giuliana; Calabrese, Francesco Maria; Eichler, Evan E; Ventura, Mario

    2017-07-01

    Dicentric chromosomes are products of genomic rearrangements that place two centromeres on the same chromosome. Due to the presence of two primary constrictions, they are inherently unstable and overcome their instability by epigenetically inactivating and/or deleting one of the two centromeres, thus resulting in functionally monocentric chromosomes that segregate normally during cell division. Our understanding to date of dicentric chromosome formation, behavior and fate has been largely inferred from observational studies in plants and humans as well as artificially produced de novo dicentrics in yeast and in human cells. We investigate the most recent product of a chromosome fusion event fixed in the human lineage, human chromosome 2, whose stability was acquired by the suppression of one centromere, resulting in a unique difference in chromosome number between humans (46 chromosomes) and our most closely related ape relatives (48 chromosomes). Using molecular cytogenetics, sequencing, and comparative sequence data, we deeply characterize the relicts of the chromosome 2q ancestral centromere and its flanking regions, gaining insight into the ancestral organization that can be easily broadened to all acrocentric chromosome centromeres. Moreover, our analyses offered the opportunity to trace the evolutionary history of rDNA and satellite III sequences among great apes, thus suggesting a new hypothesis for the preferential inactivation of some human centromeres, including IIq. Our results suggest two possible centromere inactivation models to explain the evolutionarily stabilization of human chromosome 2 over the last 5-6 million years. Our results strongly favor centromere excision through a one-step process. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Genome structure and primitive sex chromosome revealed in Populus

    SciTech Connect

    Tuskan, Gerald A; Yin, Tongming; Gunter, Lee E

    We constructed a comprehensive genetic map for Populus and ordered 332 Mb of sequence scaffolds along the 19 haploid chromosomes in order to compare chromosomal regions among diverse members of the genus. These efforts lead us to conclude that chromosome XIX in Populus is evolving into a sex chromosome. Consistent segregation distortion in favor of the sub-genera Tacamahaca alleles provided evidence of divergent selection among species, particularly at the proximal end of chromosome XIX. A large microsatellite marker (SSR) cluster was detected in the distorted region even though the genome-wide distribute SSR sites was uniform across the physical map. Themore » differences between the genetic map and physical sequence data suggested recombination suppression was occurring in the distorted region. A gender-determination locus and an overabundance of NBS-LRR genes were also co-located to the distorted region and were put forth as the cause for divergent selection and recombination suppression. This hypothesis was verified by using fine-scale mapping of an integrated scaffold in the vicinity of the gender-determination locus. As such it appears that chromosome XIX in Populus is in the process of evolving from an autosome into a sex chromosome and that NBS-LRR genes may play important role in the chromosomal diversification process in Populus.« less

  2. Stochastic phase segregation on surfaces

    PubMed Central

    Gera, Prerna

    2017-01-01

    Phase separation and coarsening is a phenomenon commonly seen in binary physical and chemical systems that occur in nature. Often, thermal fluctuations, modelled as stochastic noise, are present in the system and the phase segregation process occurs on a surface. In this work, the segregation process is modelled via the Cahn–Hilliard–Cook model, which is a fourth-order parabolic stochastic system. Coarsening is analysed on two sample surfaces: a unit sphere and a dumbbell. On both surfaces, a statistical analysis of the growth rate is performed, and the influence of noise level and mobility is also investigated. For the spherical interface, it is also shown that a lognormal distribution fits the growth rate well. PMID:28878994

  3. Arsenic-induced Aurora-A activation contributes to chromosome instability and tumorigenesis

    NASA Astrophysics Data System (ADS)

    Wu, Chin-Han; Tseng, Ya-Shih; Yang, Chao-Chun; Kao, Yu-Ting; Sheu, Hamm-Ming; Liu, Hsiao-Sheng

    2013-11-01

    Arsenic may cause serious environmental pollution and is a serious industrial problem. Depending on the dosage, arsenic may trigger the cells undergoing either proliferation or apoptosis-related cell death. Because of lack of the proper animal model to study arsenic induced tumorigenesis, the accurate risk level of arsenic exposure has not been determined. Arsenic shows genotoxic effect on human beings who uptake water contaminated by arsenic. Chromosome aberration is frequently detected in arsenic exposure-related diseases and is associated with increased oxidative stress and decreased DNA repairing activity, but the underlying mechanism remains elusive. Aurora-A is a mitotic kinase, over-expression of Aurora-A leads to centrosome amplification, chromosomal instability and cell transformation. We revealed that Aurora-A is over-expressed in the skin and bladder cancer patients from blackfoot-disease endemic areas. Our cell line studies reveal that arsenic exposure between 0.5 μM and 1 μM for 2-7 days are able to induce Aurora-A expression and activation based on promoter activity, RNA and protein analysis. Aurora-A overexpression further increases the frequency of unsymmetrical chromosome segregation through centrosome amplification followed by cell population accumulated at S phase in immortalized keratinocyte (HaCaT) and uroepithelial cells (E7). Furthermore, Aurora-A over-expression was sustained for 1-4 weeks by chronic treatment of immortalized bladder and skin cells with NaAsO2. Aurora-A promoter methylation and gene amplification was not detected in the long-term arsenic treated E7 cells. Furthermore, the expression level of E2F1 transcription factor (E2F1) is increased in the presence of arsenic, and arsenic-related Aurora-A over-expression is transcriptionally regulated by E2F1. We further demonstrated that overexpression of Aurora-A and mutant Ha-ras or Aurora-A and mutant p53 may act additively to trigger arsenic-related bladder and skin cancer

  4. Mechanics of kinetochore microtubules and their interactions with chromosomes during cell division

    NASA Astrophysics Data System (ADS)

    Nazockdast, Ehssan; Fürthauer, Sebastian; Redemann, Stephanie; Baumgart, Johannes; Lindow, Norbert; Kratz, Andrea; Prohaska, Steffen; Müller-Reichert, Thomas; Shelley, Michael

    2016-11-01

    The accurate segregation of chromosomes, and subsequent cell division, in Eukaryotic cells is achieved by the interactions of an assembly of microtubules (MTs) and motor-proteins, known as the mitotic spindle. We use a combination of our computational platform for simulating cytoskeletal assemblies and our structural data from high-resolution electron tomography of the mitotic spindle, to study the kinetics and mechanics of MTs in the spindle, and their interactions with chromosomes during chromosome segregation in the first cell division in C.elegans embryo. We focus on kinetochore MTs, or KMTs, which have one end attached to a chromosome. KMTs are thought to be a key mechanical component in chromosome segregation. Using exploratory simulations of MT growth, bending, hydrodynamic interactions, and attachment to chromosomes, we propose a mechanical model for KMT-chromosome interactions that reproduces observed KMT length and shape distributions from electron tomography. We find that including detailed hydrodynamic interactions between KMTs is essential for agreement with the experimental observations.

  5. The cnm locus, a canine homologue of human autosomal forms of centronuclear myopathy, maps to chromosome 2.

    PubMed

    Tiret, Laurent; Blot, Stéphane; Kessler, Jean-Louis; Gaillot, Hugues; Breen, Matthew; Panthier, Jean-Jacques

    2003-09-01

    Myotubular/centronuclear myopathies are a nosological group of hereditary disorders characterised by severe architectural and metabolic remodelling of skeletal muscle fibres. In most myofibres, nuclei are found at an abnormal central position within a halo devoid of myofibrillar proteins. The X-linked form (myotubular myopathy) is the most prevalent and severe form in human, leading to death during early postnatal life. Maturation of fibres is not completed and fibres resemble myotubes. Linkage analysis in human has helped to identify MTM1 as the morbid gene. MTM1 encodes myotubularin, a dual protein phosphatase. In families in which myotubular myopathy segregates, detected mutations in MTM1 abolish the specific phosphatase activity targeting the second messenger phosphatidylinositol 3-phosphate. Autosomal forms (centronuclear) have a later onset and are often compatible with life. At birth, fibres are normally constituted but progressively follow remodelling with a secondary centralisation of nuclei. Their prevalence is low; hence, no linkage data can be performed and no molecular aetiology is known. In the Labrador Retriever, a spontaneous disorder strikingly mimics the clinical evolution of the human centronuclear myopathy. We have established a canine pedigree and show that the disorder segregates as an autosomal recessive trait in that pedigree. We have further mapped the dog locus to a region on chromosome 2 that is orthologous to human chromosome 10p. To date, no human MTM1 gene member has been mapped to this genetic region. This report thus describes the first spontaneous mammalian model of centronuclear myopathy and defines a new locus for this group of diseases.

  6. Forces on a segregating particle

    NASA Astrophysics Data System (ADS)

    Lueptow, Richard M.; Shankar, Adithya; Fry, Alexander M.; Ottino, Julio M.; Umbanhowar, Paul B.

    2017-11-01

    Size segregation in flowing granular materials is not well understood at the particle level. In this study, we perform a series of 3D Discrete Element Method (DEM) simulations to measure the segregation force on a single spherical test particle tethered to a spring in the vertical direction in a shearing bed of particles with gravity acting perpendicular to the shear. The test particle is the same size or larger than the bed particles. At equilibrium, the downward spring force and test particle weight are offset by the upward buoyancy-like force and a size ratio dependent force. We find that the buoyancy-like force depends on the bed particle density and the Voronoi volume occupied by the test particle. By changing the density of the test particle with the particle size ratio such that the buoyancy force matches the test particle weight, we show that the upward size segregation force is a quadratic function of the particle size ratio. Based on this, we report an expression for the net force on a single particle as the sum of a size ratio dependent force, a buoyancy-like force, and the weight of the particle. Supported by NSF Grant CBET-1511450 and the Procter and Gamble Company.

  7. Identification of supernumerary ring chromosome 1 mosaicism using fluorescence in situ hybridization.

    PubMed

    Chen, H; Tuck-Muller, C M; Batista, D A; Wertelecki, W

    1995-03-27

    We report on a 15-year-old black boy with severe mental retardation, multiple congenital anomalies, and a supernumerary ring chromosome mosaicism. Fluorescence in situ hybridization with a chromosome 1 painting probe (pBS1) identified the ring as derived from chromosome 1. The karyotype was 46,XY/47,XY,+r(1)(p13q23). A review showed 8 reports of ring chromosome 1. In 5 cases, the patients had a non-supernumerary ring chromosome 1 resulting in partial monosomies of the short and/or long arm of chromosome 1. In 3 cases, the presence of a supernumerary ring resulted in partial trisomy of different segments of chromosome 1. In one of these cases the supernumerary ring was composed primarily of the centromere and the heterochromatic region of chromosome 1, resulting in normal phenotype. Our patient represents the third report of a supernumerary ring chromosome 1 resulting in abnormal phenotype.

  8. Methods of biological dosimetry employing chromosome-specific staining

    DOEpatents

    Gray, Joe W.; Pinkel, Daniel

    2000-01-01

    Methods and compositions for staining based upon nucleic acid sequence that employ nucleic acid probes are provided. Said methods produce staining patterns that can be tailored for specific cytogenetic analyses. Said probes are appropriate for in situ hybridization and stain both interphase and metaphase chromosomal material with reliable signals. The nucleic acid probes are typically of a complexity greater than 50 kb, the complexity depending upon the cytogenetic application. Methods are provided to disable the hybridization capacity of shared, high copy repetitive sequences and/or remove such sequences to provide for useful contrast. Still further methods are provided to produce chromosome-specific staining reagents which are made specific to the targeted chromosomal material, which can be one or more whole chromosomes, one or more regions on one or more chromosomes, subsets of chromosomes and/or the entire genome. Probes and test kits are provided for use in tumor cytogenetics, in the detection of disease related loci, in analysis of structural abnormalities, such as translocations, and for biological dosimetry. Further, methods and prenatal test kits are provided to stain targeted chromosomal material of fetal cells, including fetal cells obtained from maternal blood. Still further, the invention provides for automated means to detect and analyse chromosomal abnormalities.

  9. Methods And Compositions For Chromosome-Specific Staining

    DOEpatents

    Gray, Joe W.; Pinkel, Daniel

    2003-08-19

    Methods and compositions for staining based upon nucleic acid sequence that employ nucleic acid probes are provided. Said methods produce staining patterns that can be tailored for specific cytogenetic analyses. Said probes are appropriate for in situ hybridization and stain both interphase and metaphase chromosomal material with reliable signals. The nucleic acid probes are typically of a complexity greater than 50 kb, the complexity depending upon the cytogenetic application. Methods are provided to disable the hybridization capacity of shared, high copy repetitive sequences and/or remove such sequences to provide for useful contrast. Still further methods are provided to produce chromosome-specific staining reagents which are made specific to the targeted chromosomal material, which can be one or more whole chromosomes, one or more regions on one or more chromosomes, subsets of chromosomes and/or the entire genome. Probes and test kits are provided for use in tumor cytogenetics, in the detection of disease related loci, in analysis of structural abnormalities, such as translocations, and for biological dosimetry. Further, methods and prenatal test kits are provided to stain targeted chromosomal material of fetal cells, including fetal cells obtained from maternal blood. Still further, the invention provides for automated means to detect and analyse chromosomal abnormalities.

  10. MMPI Profiles of Males with Abnormal Sex Chromosome Complements

    ERIC Educational Resources Information Center

    Rosen, M.; And Others

    1971-01-01

    Nine males with Klinefelter's syndrome (XXY) and seven XYY males, located primarily in prisons and psychiatric hospitals, were administered the Minnesota Multiphasic Personality Inventory. (Author/KW)

  11. Chromosomal abnormalities and molecular landscape of metastasizing mucinous salivary adenocarcinoma

    PubMed Central

    Panaccione, Alex; Zhang, Yi; Mi, Yanfang; Mitani, Yoshitsugu; Yan, Guo; Prasad, Manju L.; McDonald, W. Hayes; El-Naggar, Adel K.; Yarbrough, Wendell G.; Ivanov, Sergey V.

    2017-01-01

    Background Mucinous adenocarcinoma of the salivary gland (MAC) is a lethal cancer with unknown molecular etiology and a high propensity to lymph node metastasis. Mostly due to its orphan status, MAC remains one of the least explored cancers that lacks cell lines and mouse models that could help translational and pre-clinical studies. Surgery with or without radiation remains the only treatment modality but poor overall survival (10-year, 44%) underscores the urgent need for mechanism-based therapies. Methods We developed the first patient-derived xenograft (PDX) model for pre-clinical MAC studies and a cell line that produces aggressively growing tumors after subcutaneous inj