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
RNA Polymerase I Propagates Unidirectional Spreading of rDNA Silent Chromatin
TL;DR: It is demonstrated that rDNA silencing spreads into the centromere-proximal unique sequence located downstream of RNA polymerase I (Pol I) transcription, but fails to enter the upstream telomere-proXimal sequences.
Journal ArticleDOI
Associations between MeCP2 mutations, X-chromosome inactivation, and phenotype.
TL;DR: The relationship between type of MeCP2 mutation, X-inactivation status, and clinical phenotype of Rett syndrome is complex and likely involves other environmental and polygenic modifiers.
Journal ArticleDOI
Integrated kinetics of X chromosome inactivation in differentiating embryonic stem cells.
TL;DR: An integrated analysis of the sequence of early events and chromatin modifications underlying X inactivation in differentiating female ES cells is presented and characteristic histone modification patterns can be found on the X chromosome at mitosis, suggesting that they represent true epigenetic marks of the inactive state.
Journal ArticleDOI
Haploid selection in animals
Sarah B. Joseph,Mark Kirkpatrick +1 more
TL;DR: The topic is ripe for development: refined data about which loci experience haploid selection would open the door to a variety of comparative approaches that could illuminate how diverse forms of selection mold patterns of genetic variation.
Journal ArticleDOI
Imprinted silencing of Slc22a2 and Slc22a3 does not need transcriptional overlap between Igf2r and Air
TL;DR: Although these results do not completely exclude a role for a double‐stranded RNA silencing mechanism, they do allow the possibility that the Air RNA has intrinsic cis silencing properties.
References
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Journal ArticleDOI
Rett syndrome is caused by mutations in X-linked MECP2, encoding methyl-CpG-binding protein 2.
Ruthie E. Amir,Ignatia B. Van den Veyver,Mimi Wan,Charles Q. Tran,Uta Francke,Huda Y. Zoghbi +5 more
TL;DR: This study reports the first disease-causing mutations in RTT and points to abnormal epigenetic regulation as the mechanism underlying the pathogenesis of RTT.
Journal ArticleDOI
Demethylation of the zygotic paternal genome
TL;DR: It is shown that the paternal genome in the mouse is significantly and actively demethylated within 6–8 hours of fertilization, before the onset of DNA replication, whereas the maternal genome is dem methylated after several cleavage divisions.
Journal ArticleDOI
Requirement for Xist in X chromosome inactivation
Graeme D. Penny,Graham F. Kay,Graham F. Kay,Steven A. Sheardown,Sohaila Rastan,Sohaila Rastan,Neil Brockdorff +6 more
TL;DR: Evidence for gene targeting of Xist, the proposed candidate for the X inactivation centre, is provided, and its absolute requirement in the process of X chromosome inactivation is provided.
Journal ArticleDOI
Chromosome instability and immunodeficiency syndrome caused by mutations in a DNA methyltransferase gene.
Guoliang Xu,Timothy H. Bestor,Déborah Bourc'his,Chih-Lin Hsieh,Niels Tommerup,Merete Bugge,Maj Hultén,Xiaoyan Qu,James J. Russo,E. Viegas-Péquignot +9 more
TL;DR: It is shown that five unrelated ICF patients have mutations in both alleles of the gene that encodes DNA methyltransferase 3B (refs 5, 6), which is the only genetic disorder known to involve constitutive abnormalities of genomic methylation patterns.
Journal ArticleDOI
Tsix , a gene antisense to Xist at the X-inactivation centre
TL;DR: Tsix RNA is a 40-kb RNA originating 15 kb downstream of Xist and transcribed across the Xist locus and has features suggesting a role in regulating the early steps of X inactivation, but not the silencing step.