Further examination of the Xist promoter-switch hypothesis in X inactivation: evidence against the existence and function of a P(0) promoter.

ABSTRACT: The onset of X inactivation coincides with accumulation of Xist RNA along the future inactive X chromosome. A recent hypothesis proposed that accumulation is initiated by a promoter switch within Xist. In this hypothesis, an upstream promoter (P(0)) produces an unstable transcript, while the known downstream promoter (P(1)) produces a stable RNA. To test this hypothesis, we examined expression and half-life of Xist RNA produced from an Xist transgene lacking P(0) but retaining P(1). We confirm the previous finding that P(0) is dispensable for Xist expression in undifferentiated cells and that P(1) can be used in both undifferentiated and differentiated cells. Herein, we show that Xist RNA initiated at P(1) is unstable and does not accumulate. Further analysis indicates that the transcripti

SUBMITTER: Warshawsky D 

PROVIDER: S-EPMC24452 | biostudies-literature | 1999 Dec

REPOSITORIES: biostudies-literature