RNA polymerase subunits and transcription factors (red) are excluded from regions where the Xist transcript (green) coats an X chromosome.

HEARD/CSHL

Silencing of the X chromosome creates a transcription-free nuclear compartment, based on findings from Julie Chaumeil, Edith Heard (Curie Institute, Paris, France), and colleagues.

For cellular gender equality, female cells silence one of their two X chromosomes. This silencing is initiated by the Xist RNA, which coats the chromosome from which it is expressed. In differentiating embryonic stem cells, the authors now show, this coating is rapidly followed by the exclusion of the transcription machinery.

The exclusion of RNA Pol II and transcription factors creates a transcription-free zone and is now the earliest event known to occur after Xist transcription. In fact, it happened even before several normally silenced X-linked genes were turned off. While still expressed, these genes were found on the periphery...

The Rockefeller University Press
2006
The Rockefeller University Press
2006
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