Report

Intersection of the RNA Interference and X-Inactivation Pathways

Science  06 Jun 2008:
Vol. 320, Issue 5881, pp. 1336-1341
DOI: 10.1126/science.1157676

You are currently viewing the abstract.

View Full Text

Via your Institution

Log in through your institution

Log in through your institution


Abstract

In mammals, dosage compensation is achieved by X-chromosome inactivation (XCI) in the female. The noncoding Xist gene initiates silencing of the X chromosome, whereas its antisense partner Tsix blocks silencing. The complementarity of Xist and Tsix RNAs has long suggested a role for RNA interference (RNAi). Here, we report that murine Xist and Tsix form duplexes in vivo. During XCI, the duplexes are processed to small RNAs (sRNAs), most likely on the active X (Xa) in a Dicer-dependent manner. Deleting Dicer compromises sRNA production and derepresses Xist. Furthermore, without Dicer, Xist RNA cannot accumulate and histone 3 lysine 27 trimethylation is blocked on the inactive X (Xi). The defects are partially rescued by truncating Tsix. Thus, XCI and RNAi intersect, down-regulating Xist on Xa and spreading silencing on Xi.

View Full Text

Cited By...