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
Same origins of DNA replication function on the active and inactive human X chromosomes.
TL;DR: The results of these studies clearly demonstrated that the human HPRT and G6PD origins of replication were utilized to the same extent in the active and the inactive X chromosomes.
Journal ArticleDOI
X-linked genes in female embryonic stem cells carry an epigenetic mark prior to the onset of X inactivation
Laura P. O'Neill,Tamzin E. Randall,Jayne S. Lavender,Hugh T. Spotswood,Jeannie T. Lee,Jeannie T. Lee,Bryan M. Turner +6 more
TL;DR: The selective marking of X-linked genes in female ES cells in a way that distinguishes them from the equivalent genes in males, is unprecedented and it is suggested that the mark forms part of a chromatin-based mechanism that restricts X-inactivation to cells with more than one X chromosome.
Journal ArticleDOI
Lack of expression of XIST from a small ring X chromosome containing the XIST locus in a girl with short stature, facial dysmorphism and developmental delay.
TL;DR: A 46,X,r(X) karyotype was found in a three and a half year old girl with short stature, facial dysmorphism and developmental delay, consistent with the phenotype described in a limited number of patients with small ring X chromosomes lacking the XIST locus.
Journal ArticleDOI
Statistical signals in bioinformatics
TL;DR: The Arthur M. Sackler Colloquium of the National Academy of Sciences, "Frontiers in Bioinformatics: Unsolved Problems and Challenges," organized by David Eisenberg, Russ Altman, and myself, was held October 15-17, 2004, to provide a forum for discussing concepts and methods in bioinformatrics serving the biological and medical sciences.
Journal ArticleDOI
Should There Be Sex-Specific Criteria for the Diagnosis and Treatment of Heart Failure?
TL;DR: Evidence is provided that inclusion of female animals in pre-clinical studies of heart failure and in development of imaging modalities to assess cardiac function might provide new information from which one could develop sex-specific diagnostic criteria and approaches to treatment.
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.
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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.
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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.