X Chromosome Inactivation
Mostrando 13-24 de 235 artigos, teses e dissertações.
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13. X chromosome inactivation of the human TIMP gene.
X chromosome inactivation results in the cis-limited inactivation of most, but not all, genes on one of the two X chromosomes in mammalian females. The molecular basis for inactivation is unknown. In order to examine the transcriptional activity of human X-linked genes, a series of mouse-human somatic cell hybrids under positive selection for the active or i
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14. The X chromosome of monotremes shares a highly conserved region with the eutherian and marsupial X chromosomes despite the absence of X chromosome inactivation.
Eight genes, located on the long arm of the human X chromosome and present on the marsupial X chromosome, were mapped by in situ hybridization to the chromosomes of the platypus Ornithorhynchus anatinus, one of the three species of monotreme mammals. All were located on the X chromosome. We conclude that the long arm of the human X chromosome represents a hi
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15. The role of X-chromosome inactivation in female predisposition to autoimmunity
We propose that the phenomenon of X-chromosome inactivation in females may constitute a risk factor for loss of T-cell tolerance; specifically that skewed X-chromosome inactivation in the thymus may lead to inadequate thymic deletion. Using a DNA methylation assay, we have examined the X-chromosome inactivation patterns in peripheral blood from normal female
BioMed Central.
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16. Inactivation of the Zfx gene on the mouse X chromosome.
ZFX, an X chromosome-linked gene encoding a zinc-finger protein, has previously been shown to escape X inactivation in humans. Here we report studies of the inactivation status of the homolog, Zfx, on the mouse X chromosome. We took advantage of both the preferential inactivation of the normal X chromosome in females carrying the T(X;16)16H translocation and
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17. Is human X chromosome inactivation a sex-determining device?
The evolutionary function of X chromosome inactivation is thought to be dosage compensation. However, there is, at present, little evidence to suggest that most X chromosome-linked genes require such compensation. Another view--that X chromosome inactivation may be related to sex determination--is examined here. Consider a hypothetical DNA sequence regulatin
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18. Cytogenetic and molecular studies on a recombinant human X chromosome: implications for the spreading of X chromosome inactivation.
A pericentric inversion of a human X chromosome and a recombinant X chromosome [rec(X)] derived from crossing-over within the inversion was identified in a family. The rec(X) had a duplication of the segment Xq26.3----Xqter and a deletion of Xp22.3----Xpter and was interpreted to be Xqter----Xq26.3::Xp22.3----Xqter. To characterize the rec(X) chromosome, dos
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19. Species Differences in TSIX/Tsix Reveal the Roles of These Genes in X-Chromosome Inactivation
Transcriptional silencing of the human inactive X chromosome is induced by the XIST gene within the human X-inactivation center. The XIST allele must be turned off on one X chromosome to maintain its activity in cells of both sexes. In the mouse placenta, where X inactivation is imprinted (the paternal X chromosome is always inactive), the maternal Xist alle
The American Society of Human Genetics.
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20. Nonrandom X chromosome DNA methylation patterns in hemophiliac females.
Molecular X chromosome inactivation analysis was used to characterize three females (and their families) with severe hemophilia. First, the maternal and paternal X chromosomes were distinguished by restriction fragment length polymorphisms (RFLPs). Second, the patterns of methylation of X chromosome genes using methylation-sensitive restriction endonucleases
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21. Skewing X chromosome choice by modulating sense transcription across the Xist locus
The X-inactive-specific transcript (Xist) locus is a cis-acting switch that regulates X chromosome inactivation in mammals. Over recent years an important goal has been to understand how Xist is regulated at the initiation of X inactivation. Here we report the analysis of a series of targeted mutations at the 5′ end of the Xist locus. A number of thes
Cold Spring Harbor Laboratory Press.
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22. Absence of methylation of a CpG-rich region at the 5' end of the MIC2 gene on the active X, the inactive X, and the Y chromosome.
We have identified and characterized a Hpa II tiny fragment (HTF) island associated with the promoter region of the pseudoautosomal gene MIC2. The MIC2 HTF island is unmethylated on both the active and inactive X chromosome and is similarly unmethylated on the Y chromosome. Unlike the majority of genes borne on the X chromosome, MIC2 fails to undergo X chrom
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23. The Role of X-Chromosome Inactivation during Spermatogenesis
Inactivation of the single X chromosome in the primary spermatocytes of species with heterogametic males is postulated as a basic control mechanism on the chromosomal level that is required for normal spermatogenesis. This view is supported by (a) cytological observations of X-chromosome allocycly in the primary spermatocytes of all male-heterogametic organi
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24. X inactivation of the FMR1 fragile X mental retardation gene.
X chromosome inactivation has been hypothesised to play a role in the aetiology and clinical expression of the fragile X syndrome. The identification of the FMR1 gene involved in fragile X syndrome allows testing of the assumption that the fragile X locus is normally subject to X inactivation. We studied the expression of the FMR1 gene from inactive X chromo