Send to

Choose Destination
Cell. 2010 Oct 29;143(3):390-403. doi: 10.1016/j.cell.2010.09.049.

The long noncoding RNA, Jpx, is a molecular switch for X chromosome inactivation.

Author information

Howard Hughes Medical Institute, Massachusetts General Hospital, Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.


Once protein-coding, the X-inactivation center (Xic) is now dominated by large noncoding RNAs (ncRNA). X chromosome inactivation (XCI) equalizes gene expression between mammalian males and females by inactivating one X in female cells. XCI requires Xist, an ncRNA that coats the X and recruits Polycomb proteins. How Xist is controlled remains unclear but likely involves negative and positive regulators. For the active X, the antisense Tsix RNA is an established Xist repressor. For the inactive X, here, we identify Xic-encoded Jpx as an Xist activator. Jpx is developmentally regulated and accumulates during XCI. Deleting Jpx blocks XCI and is female lethal. Posttranscriptional Jpx knockdown recapitulates the knockout, and supplying Jpx in trans rescues lethality. Thus, Jpx is trans-acting and functions as ncRNA. Furthermore, ΔJpx is rescued by truncating Tsix, indicating an antagonistic relationship between the ncRNAs. We conclude that Xist is controlled by two RNA-based switches: Tsix for Xa and Jpx for Xi.

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Elsevier Science Icon for PubMed Central
Loading ...
Support Center