- Xist
Xist is an RNA gene on the
X chromosome of the placental mammals that acts as major effector of theX inactivation process.The Xist RNA, a large (17 kb in humans) [cite journal |author=Brown CJ, Hendrich BD, Rupert JL, "et al" |title=The human XIST gene: analysis of a 17 kb inactive X-specific RNA that contains conserved repeats and is highly localized within the nucleus |journal=Cell |volume=71 |issue=3 |pages=527–42 |year=1992 |pmid=1423611 |doi=] transcript, is expressed on the inactive chromosome and not on the active one. It is processed similarly to mRNAs, through
splicing andpolyadenylation , however, it remains untranslated. It has been suggested that this RNA gene evolved at least partly from a protein coding gene that became apseudogene .cite journal | author = Duret L, Chureau C, Samain S, Weissenbach J, Avner P | title = The Xist RNA gene evolved in eutherians by pseudogenization of a protein-coding gene | journal = Science | volume = 312 | issue = 5780 | pages = 1653–5 | year = 2006 | pmid = 16778056 | doi = 10.1126/science.1126316 | issn = ]The inactive X is coated with this transcript, which is essential for the inactivation. X lacking Xist will not be inactivated, while duplication of the Xist gene on another chromosome causes inactivation of that chromosome.
References
External links
* [http://spot.colorado.edu/~strauswm/tech/xist_function.html Xist page of Strauss lab]
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