| First Author | Xu N | Year | 2007 |
| Journal | Nat Genet | Volume | 39 |
| Issue | 11 | Pages | 1390-6 |
| PubMed ID | 17952071 | Mgi Jnum | J:130305 |
| Mgi Id | MGI:3771454 | Doi | 10.1038/ng.2007.5 |
| Citation | Xu N, et al. (2007) Evidence that homologous X-chromosome pairing requires transcription and Ctcf protein. Nat Genet 39(11):1390-6 |
| abstractText | X-chromosome inactivation (XCI) ensures the equality of X-chromosome dosages in male and female mammals by silencing one X in the female. To achieve the mutually exclusive designation of active X (Xa) and inactive X (Xi), the process necessitates that two Xs communicate in trans through homologous pairing. Pairing depends on a 15-kb region within the genes Tsix and Xite. Here, we dissect molecular requirements and find that pairing can be recapitulated by 1- to 2-kb subfragments of Tsix or Xite with little sequence similarity. However, a common denominator among them is the presence of the protein Ctcf, a chromatin insulator that we find to be essential for pairing. By contrast, the Ctcf-interacting partner, Yy1 (ref. 8), is not required. Pairing also depends on transcription. Transcriptional inhibition prevents new pair formation but does not perturb existing pairs. The kinetics suggest a pairing half-life of <1 h. We propose that pairing requires Ctcf binding and co-transcriptional activity of Tsix and Xite. |
