Journal ArticleDOI
X-chromosome inactivation: counting, choice and initiation
Philip Avner,Edith Heard +1 more
TLDR
In many sexually dimorphic species, a mechanism is required to ensure equivalent levels of gene expression from the sex chromosomes, and in mammals, such dosage compensation is achieved by X-chromosome inactivation, a process that presents a unique medley of biological puzzles.Abstract:
In many sexually dimorphic species, a mechanism is required to ensure equivalent levels of gene expression from the sex chromosomes. In mammals, such dosage compensation is achieved by X-chromosome inactivation, a process that presents a unique medley of biological puzzles: how to silence one but not the other X chromosome in the same nucleus; how to count the number of X's and keep only one active; how to choose which X chromosome is inactivated; and how to establish this silent state rapidly and efficiently during early development. The key to most of these puzzles lies in a unique locus, the X-inactivation centre and a remarkable RNA — Xist — that it encodes.read more
Citations
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Journal ArticleDOI
Epigenetic regulation of gene expression: how the genome integrates intrinsic and environmental signals
Rudolf Jaenisch,Adrian Bird +1 more
TL;DR: Advances in the understanding of the mechanism and role of DNA methylation in biological processes are reviewed, showing that epigenetic mechanisms seem to allow an organism to respond to the environment through changes in gene expression.
Journal ArticleDOI
Regulation of heterochromatic silencing and histone H3 lysine-9 methylation by RNAi.
Tom Volpe,Catherine A. Kidner,Ira M. Hall,Ira M. Hall,Grace Teng,Grace Teng,Shiv I. S. Grewal,Robert A. Martienssen +7 more
TL;DR: It is proposed that double-stranded RNA arising from centromeric repeats targets formation and maintenance of heterochromatin through RNAi.
Journal ArticleDOI
Chromatin modification and epigenetic reprogramming in mammalian development
TL;DR: The regulation of higher-order chromatin structures by DNA methylation and histone modification is crucial for genome reprogramming during early embryogenesis and gametogenesis, and for tissue-specific gene expression and global gene silencing.
Journal ArticleDOI
Non-coding RNA genes and the modern RNA world.
TL;DR: Non-coding RNAs seem to be particularly abundant in roles that require highly specific nucleic acid recognition without complex catalysis, such as in directing post-transcriptional regulation of gene expression or in guiding RNA modifications.
Journal ArticleDOI
Role of histone H3 lysine 27 methylation in X inactivation.
Kathrin Plath,Jia Fang,Susanna Mlynarczyk-Evans,Ru Cao,Kathleen A. Worringer,Hengbin Wang,Cecile C. de la Cruz,Arie P. Otte,Barbara Panning,Yi Zhang +9 more
TL;DR: It is demonstrated that transient recruitment of the Eed-Ezh2 complex to the inactive X chromosome (Xi) occurs during initiation of X inactivation in both extraembryonic and embryonic cells and is accompanied by H3-K27 methylation.
References
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Journal ArticleDOI
Xist yeast artificial chromosome transgenes function as x-inactivation centers only in multicopy arrays and not as single copies
TL;DR: It is found that single-copy transgenes, unlike multicopy arrays, can induce neither inactivation in cis nor counting, and the YACs that are tested lack sequences critical for autonomous function with respect to X inactivation.
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The Spreading of X Inactivation into Autosomal Material of an X;autosome Translocation: Evidence for a Difference between Autosomal and X-Chromosomal DNA
TL;DR: The findings are broadly consistent with the existence of genes known to escape inactivation on normal inactive X chromosomes, but the fact that a high proportion of tested autosomal genes escaped inactivation may indicate that autosomal material lacks X chromosome-specific features that are associated with the spreading and/or maintenance of inactivation.
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Higher concentrations of histone macroH2A in the Barr body are correlated with higher nucleosome density
Pierre-Yves Perche,Claire Vourc'h,Lara Konecny,Catherine Souchier,Michel Robert-Nicoud,Stefan Dimitrov,Saadi Khochbin +6 more
TL;DR: It is found that the proximity of the non-histone region of macroH2A to a promoter could lead to a specific repression of transcription, suggesting that the incorporation of macro H2A into chromatin might help to establish the stable pattern of gene expression in differentiated cells.
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Functional analysis of the DXPas34 locus, a 3' regulator of Xist expression.
TL;DR: The expression pattern of DXPas34 during early embryonic development is reported, which suggests that it could be implicated in the regulation of imprintedXist expression, and appears to be a critical regulator of Xist activity and X inactivation.
Journal ArticleDOI
Xce haplotypes show modified methylation in a region of the active X chromosome lying 3' to Xist.
TL;DR: It is reported that a region of the mouse X chromosome lying 15 kb distal to Xist contains several sites that show hypermethylation specifically associated with the active X chromosome, and it is proposed that such a region could be involved in the initial stages of the inactivation process.