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Sanyal Swastika - - 2013
One of the key features of meiosis is that shugoshin in complex with protein phosphatase 2A (PP2A) protects centromeric cohesin during meiosis I, but not during meiosis II. A new model suggests that a PP2A inhibitor mediates deprotection of centromeric cohesin during meiosis II.
Kazuki Y - - 2011
Human artificial chromosomes (HACs) have several advantages as gene therapy vectors, including stable episomal maintenance, and the ability to carry large gene inserts. We previously developed HAC vectors from the normal human chromosomes using a chromosome engineering technique. However, endogenous genes were remained in these HACs, limiting their therapeutic applications. ...
Tian Di - - 2010
Once protein-coding, the X-inactivation center (Xic) is now dominated by large noncoding RNAs (ncRNA). X chromosome inactivation (XCI) equalizes gene expression between mammalian males and females by inactivating one X in female cells. XCI requires Xist, an ncRNA that coats the X and recruits Polycomb proteins. How Xist is controlled ...
Shin Jongdae - - 2010
Two forms of X-chromosome inactivation (XCI) ensure the selective silencing of female sex chromosomes during mouse embryogenesis. Imprinted XCI begins with the detection of Xist RNA expression on the paternal X chromosome (Xp) at about the four-cell stage of embryonic development. In the embryonic tissues of the inner cell mass, a ...
Yano S - - 2011
Simpson-Golabi-Behmel syndrome (SGBS) is an overgrowth/multiple congenital anomalies syndrome with an X-linked inheritance. Most cases of SGBS are attributed to mutations in the glypican 3-gene (GPC3), which is highly expressed in the mesodermal embryonic tissues and involves in a local growth regulation. Typical clinical features include pre/postnatal overgrowth, developmental delay, ...
Kelkar Ashwin - - 2010
X chromosome inactivation occurs in female mammals for the purpose of equalisation of dosage of X linked genes between the two sexes. In eutherian mammals, one of the two copies of the X chromosome present in female individuals is silenced. Epigenetic modifications of both DNA and histones have been implicated ...
Inoue Kimiko - - 2010
Cloning mammals by means of somatic cell nuclear transfer (SCNT) is highly inefficient because of erroneous reprogramming of the donor genome. Reprogramming errors appear to arise randomly, but the nature of nonrandom, SCNT-specific errors remains elusive. We found that Xist, a noncoding RNA that inactivates one of the two X ...
Hasegawa Yuko Y RNA Biology Laboratory, RIKEN Advanced Research Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, - - 2010
In XX female mammals, one of the two X chromosomes is epigenetically inactivated to equalize gene expression with XY males. The formation of the inactive X chromosome (Xi) is regulated by an X-linked long noncoding RNA Xist, which accumulates on the entire length of the chromosome in cis and induces ...
Tchieu Jason - - 2010
Generating induced pluripotent stem cells (iPSCs) requires massive epigenome reorganization. It is unclear whether reprogramming of female human cells reactivates the inactive X chromosome (Xi), as in mouse. Here we establish that human (h)iPSCs derived from several female fibroblasts under standard culture conditions carry an Xi. Despite the lack of ...
Brooks Wesley H - - 2010
Autoimmune diseases appear to have multiple contributing factors including genetics, epigenetics, environmental factors, and aging. The predominance of females among patients with autoimmune diseases suggests possible involvement of the X chromosome and X chromosome inactivation. X chromosome inactivation is an epigenetic event resulting in multiple levels of control for modulation ...
Royce-Tolland Morgan E ME Department of Biochemistry and Biophysics, University of California, San Francisco, California, - - 2010
One X chromosome, selected at random, is silenced in each female mammalian cell. Xist encodes a noncoding RNA that influences the probability that the cis-linked X chromosome will be silenced. We found that the A-repeat, a highly conserved element within Xist, is required for the accumulation of spliced Xist RNA. ...
Zheng Suqin - - 2010
Focal nodular hyperplasia (FNH) is considered a benign tumor of the liver. However, the biologic nature and clonality status of FNH are not well established. We sought to determine the clonality and TP53 mutation status of FNH to better characterize the nature of FNH. We analyzed 15 cases of FNH ...
Chow Jennifer C JC Institut Curie, Paris F-75248, - - 2010
During X chromosome inactivation (XCI), Xist RNA coats and silences one of the two X chromosomes in female cells. Little is known about how XCI spreads across the chromosome, although LINE-1 elements have been proposed to play a role. Here we show that LINEs participate in creating a silent nuclear ...
Dementyeva Elena V EV Russian Academy of Sciences, Siberian Department, Institute of Cytology and Genetics, ac. Lavrentyev Avenue 10, Novosibirsk, - - 2010
During early development in female mammals, most genes on one of the two X-chromosomes undergo transcriptional silencing. In the extraembryonic lineages of some eutherian species, imprinted X-inactivation of the paternal X-chromosome occurs. In the cells of the embryo proper, the choice of the future inactive X-chromosome is random. We mapped ...
Faerch Mia - - 2010
To establish the clinical phenotype and genetic background in a family with diabetes insipidus. The subjects were a sister and brother, aged 34 and 27 years, respectively, with a history of polyuria since infancy. Clinical testing confirmed a diagnosis of congenital nephrogenic diabetes insipidus (CNDI) in both. Samples of purified ...
Vazna Alzbeta - - 2010
We describe a girl with mild facial anomalies, mild mental retardation, and atypical autism with a remarkable behavioral phenotype of persistent anger, aggression, and dysphoria. The occurrence of late-onset tremor and premature ovarian failure in the maternal branch of the family pointed to a possible defect in the FMR1 gene. ...
Namekawa Satoshi H - - 2010
Mammals compensate for unequal X-linked gene dosages between the sexes by inactivating one X chromosome in the female. In marsupials and in the early mouse embryo, X chromosome inactivation (XCI) is imprinted to occur selectively on the paternal X chromosome (X(P)). The mechanisms and events underlying X(P) imprinting remain unclear. ...
Tüttelmann F - - 2010
Klinefelter's syndrome (KS) is the most common chromosome aneuploidy in males, characterized by at least one supernumerary X chromosome. Although extensively studied, the pathophysiology, i.e. the link between the extra X and the phenotype, largely remains unexplained. The scope of this review is to summarize the progress made in recent ...
Zhu Xingwang - - 2010
Rett syndrome is an X-linked neurodevelopmental disorder that predominantly affects females. It is caused by mutations in methyl-CpG-binding protein 2 gene. Due to the sex-limited expression, it has been suggested that de novo X-linked mutations may exclusively occur in male germ cells and thus only females are affected. In this ...
Bernard David J - - 2010
Mutations in the human OCRL gene, which encodes a phosphatidylinositol(4,5)bisphosphate 5-phosphatase, result in the X-linked oculocerebrorenal syndrome of Lowe. Mice with a targeted disruption of Ocrl have no phenotypic abnormalities. Targeted disruption of its closest paralog, Inpp5b, causes male infertility in the 129S6 background. Mice with disruptions of both genes ...
Graves J A M - - 2010
Sex chromosomes have a disproportionate influence on health and disease. Both the X and Y are atypical in gene content and activity, as a result of their unique evolutionary trajectory. The X and Y chromosomes originated in a pair of autosomes, and differentiated as the Y chromosome degenerated progressively. The ...
Tycko Benjamin - - 2010
In this issue of The Journal, an article by Schalkwyk et al.(1) shows the landscape of allele-specific DNA methylation (ASM) in the human genome. ASM has long been studied as a hallmark of imprinted genes, and a chromosome-wide version of this phenomenon occurs, in a random fashion, during X chromosome ...
Pullirsch Dieter D Research Institute of Molecular Pathology, Dr Bohr-Gasse 7, 1030 Vienna, - - 2010
Mammals compensate X chromosome gene dosage between the sexes by silencing of one of the two female X chromosomes. X inactivation is initiated in the early embryo and requires the non-coding Xist RNA, which encompasses the inactive X chromosome (Xi) and triggers its silencing. In differentiated cells, several factors including ...
Erwin Jennifer A - - 2010
This unit describes a method of performing fluorescent in situ hybridization (FISH) of XIST and Cot-1 RNA in human pluripotent stem cells (hPSC) to characterize the epigenetic status of X-chromosome inactivation (XCI). hPSC laboratories commonly practice karyotypic analysis to monitor genetic stability; however, epigenetic stability is often overlooked. Several laboratories ...
Barakat Tahsin Stefan - - 2010
In female somatic cells of mammalian species one X chromosome is inactivated to ensure dosage equality of X-encoded genes between females and males, during development and adulthood. X chromosome inactivation (XCI) involves various epigenetic mechanisms, including RNA mediated gene silencing in cis, DNA methylation, and changes in chromatin modifications and ...
Leeb M M Research Institute of Molecular Pathology, Vienna, - - 2010
Mammals inactivate one of the two female X chromosomes to compensate for the unequal copy number of X-linked genes between males and females. This process of X inactivation entails the silencing of one X chromosome in a developmentally regulated manner. In this work, we review recent findings in X inactivation ...
Kaupert Laura C - - 2010
BACKGROUND: The androgen receptor gene is located on the X chromosome with a polymorphic tract of CAG repeats that is inversely correlated to the receptor's transactivation activity. A short CAG tract is associated with hyperandrogenic disorders. In women, one of the X chromosomes is inactivated and the X chromosome inactivation ...
Ferreira Susana I - - 2010
Premature ovarian failure (POF) has repeatedly been associated to X-chromosome deletions. FMR1 gene premutation allele's carrier women have an increased risk for POF. We intent to determine the cause of POF in a 29 year old female, evaluating both of these situations. Concomitant analysis of FMR1 gene CGG repeat number ...
Myszka A - - 2010
We report on a 13-month-old girl showing dysmorphic features and a delay in psychomotor development. She was diagnosed with a balanced de novo translocation 46,X,t(X;13)(p11.2;p13) and non-random inactivation of the X chromosome. FISH analysis, employing the X chromosome centromere and XIST-region-specific probes, showed that the XIST locus was not involved ...
Lelièvre Jean-Marc - - 2010
Expression of several copies of the heat-inducible Hsp70.1Luciferase (LUC) transgene inserted at a single X chromosome locus of a bull (Bos taurus) was assessed in females after X-chromosome inactivation (XCI). Furthermore, impact of the chromosomal environment on the spontaneous expression of these transgene copies before XCI was studied during early ...
Thorogood Nancy P - - 2010
X-chromosome inactivation occurs early in mammalian development and results in the inactive X chromosome acquiring numerous hallmarks of heterochromatin. While XIST is a key player in the inactivation process, the method of action of this ncRNA is yet to be determined. To assess which features of heterochromatin may be directly ...
Moreira de Mello Joana Carvalho - - 2010
Imprinted inactivation of the paternal X chromosome in marsupials is the primordial mechanism of dosage compensation for X-linked genes between females and males in Therians. In Eutherian mammals, X chromosome inactivation (XCI) evolved into a random process in cells from the embryo proper, where either the maternal or paternal X ...
Lopes Alexandra M AM IPATIMUP, Instituto de Patologia e Imunologia Molecular da Universidade do Porto, 4200-465 Porto, Portugal. - - 2010
X monosomic mice (39,XO) have a remarkably mild phenotype when compared to women with Turner syndrome (45,XO). The generally accepted hypothesis to explain this discrepancy is that the number of genes on the mouse X chromosome which escape X inactivation, and thus are expressed at higher levels in females, is ...
Tang Y Amy YA MRC Clinical Sciences Centre, Faculty of Medicine ICSTM, Hammersmith Hospital, London, UK. - - 2010
X chromosome inactivation, the mechanism used by mammals to equalise dosage of X-linked genes in XX females relative to XY males, is triggered by chromosome-wide localisation of a cis-acting non-coding RNA, Xist. The mechanism of Xist RNA spreading and Xist-dependent silencing is poorly understood. A large body of evidence indicates ...
Goto Yuji - - 2009
In mammals, the dosage compensation of sex chromosomes between males and females is achieved by transcriptional inactivation of one of the two X chromosomes in females. However, a number of genes escape X-inactivation in humans. It remains poorly understood how the transcriptional activity of these 'escape genes' is maintained despite ...
Jonkers Iris - - 2009
In somatic cells of female placental mammals, one X chromosome is inactivated to minimize sex-related dosage differences of X-encoded genes. Random X chromosome inactivation (XCI) in the embryo is a stochastic process, in which each X has an independent probability to initiate XCI, triggered by the nuclear concentration of one ...
Nora Elphège P - - 2009
How do mammals count their X chromosomes and keep only one X active per cell? In this issue, Jonkers et al. (2009) show that Rnf12/RLIM, encoded by the X-linked gene Rnf12, induces X chromosome inactivation only when present above a certain threshold, a condition fulfilled when at least two Xs ...
Agrelo Ruben R Research Institute of Molecular Pathology, Vienna, Austria. - - 2009
In mammals, silencing of one of the two X chromosomes is necessary to achieve dosage compensation. The non coding RNA Xist triggers X inactivation. Gene silencing by Xist is only possible in certain developmental contexts that only exist in cells of the early embryo and specific hematopoietic progenitors. Critical silencing ...
Yan Wei - - 2009
Mammalian females have two X chromosomes, while males have only one X plus a Y chromosome. In order to balance X-linked gene dosage between the sexes, one X chromosome undergoes inactivation during development of female embryos. This process has been termed X-chromosome inactivation (XCI). Inactivation of the single X chromosome ...
Minks Jakub - - 2009
X-chromosome inactivation is a fascinating epigenetic phenomenon that is initiated by expression of a noncoding (nc)RNA, XIST, and results in transcriptional silencing of 1 female X. The process requires a series of events that begins even before XIST expression, and culminates in an active and a silent X within the ...
Brix Thomas Heiberg - - 2009
Ahigher frequency of skewed X chromosome inactivation (XCI) is found in patients with autoimmune thyroid disease (AITD) than in controls. Although goitre is often present in AITD, a recent study failed to show an association between XCI and clinically overt nontoxic goitre. However, the etiology of overt goitre is complex, ...
Perez-Cano Hector J - - 2009
Choroideremia is an X-linked recessive retinal dystrophy characterized by progressive loss of the photoreceptor, the retinal pigment epithelium, and the choriocapillaris layers which ultimately can result in blindness by the fifth decade of life. The disease is caused by mutations in the gene CHM, which encodes a protein involved in ...
Brix Thomas Heiberg - - 2010
An increased frequency of skewed X-chromosome inactivation (XCI) is found in clinically overt autoimmune thyroid disease (AITD) compared with controls. Whether skewed XCI is involved in the pathogenesis of autoantibodies to thyroid peroxidase (TPOAb) in euthyroid subjects is unknown. To examine the impact of XCI on the serum concentration of ...
Mahadevaiah Shantha K SK MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, - - 2009
In female marsupials, X chromosome inactivation (XCI) is imprinted, affecting the paternal X chromosome. One model, supported by recent studies, proposes that XCI in marsupials is achieved through inheritance of an already silent X chromosome from the father, with XCI initiated by meiotic sex chromosome inactivation (MSCI). This model is ...
Hall Lisa L - - 2009
How XIST RNA strictly localizes across the inactive X chromosome is unknown; however, prophase release of human XIST RNA provides a clue. Tests of inhibitors that mimic mitotic chromatin modifications implicated an indirect role of PP1 (protein phosphatase 1), potentially via its interphase repression of Aurora B kinase (AURKB), which ...
Stabellini Raquel - - 2009
X chromosome inactivation (XCI) is a comprehensively studied phenomenon that helped to highlight the heritable nature of epigenetic modifications. Although it consists of the transcriptional inactivation of a whole X chromosome in females, some genes escape this process and present bi-allelic expression. Using human fibroblasts with skewed inactivation, we determined ...
Marks Hendrik H Department of Molecular Biology, Faculty of Science, Nijmegen Centre for Molecular Life Sciences (NCMLS), Radboud University Nijmegen, Nijmegen, The - - 2009
Differentiation of female murine ES cells triggers silencing of one X chromosome through X-chromosome inactivation (XCI). Immunofluorescence studies showed that soon after Xist RNA coating the inactive X (Xi) undergoes many heterochromatic changes, including the acquisition of H3K27me3. However, the mechanisms that lead to the establishment of heterochromatin remain unclear. ...
Kalantry Sundeep S Department of Genetics, and Carolina Center for Genome Sciences, University of North Carolina, Chapel Hill, North Carolina 27599-7264, - - 2009
XX female mammals undergo transcriptional silencing of most genes on one of their two X chromosomes to equalize X-linked gene dosage with XY males in a process referred to as X-chromosome inactivation (XCI). XCI is an example of epigenetic regulation. Once enacted in individual cells of the early female embryo, ...
Donohoe Mary E - - 2009
Pluripotency of embryonic stem (ES) cells is controlled by defined transcription factors. During differentiation, mouse ES cells undergo global epigenetic reprogramming, as exemplified by X-chromosome inactivation (XCI) in which one female X chromosome is silenced to achieve gene dosage parity between the sexes. Somatic XCI is regulated by homologous X-chromosome ...
van den Berg Ilse M - - 2009
X chromosome inactivation (XCI) is the mammalian mechanism that compensates for the difference in gene dosage between XX females and XY males. Genetic and epigenetic regulatory mechanisms induce transcriptional silencing of one X chromosome in female cells. In mouse embryos, XCI is initiated at the preimplantation stage following early whole-genome ...
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