The human XIST gene: analysis of a 17 kb inactive X-specific RNA that contains conserved repeats and is highly localized within the nucleus
Department of Cell Biology
Medical Subject Headings
Base Sequence; Cell Nucleus; Conserved Sequence; *Dosage Compensation, Genetic; Exons; Female; Humans; Introns; Molecular Sequence Data; RNA, Messenger; *RNA, Untranslated; Repetitive Sequences, Nucleic Acid; Sequence Alignment; Sequence Homology, Nucleic Acid; Sex Chromatin; Transcription Factors; X Chromosome
Cell Biology | Life Sciences | Medicine and Health Sciences
X chromosome inactivation in mammalian females results in the cis-limited transcriptional inactivity of most of the genes on one X chromosome. The XIST gene is unique among X-linked genes in being expressed exclusively from the inactive X chromosome. Human XIST cDNAs containing at least eight exons and totaling 17 kb have been isolated and sequenced within the region on the X chromosome known to contain the X inactivation center. The XIST gene includes several tandem repeats, the most 5' of which are evolutionarily conserved. The gene does not contain any significant conserved ORFs and thus does not appear to encode a protein, suggesting that XIST may function as a structural RNA within the nucleus. Consistent with this, fluorescence in situ hybridization experiments demonstrate localization of XIST RNA within the nucleus to a position indistinguishable from the X inactivation-associated Barr body.
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Citation: Cell. 1992 Oct 30;71(3):527-42.