کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
2037810 | 1072338 | 2008 | 12 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: X Inactivation Counting and Choice Is a Stochastic Process: Evidence for Involvement of an X-Linked Activator X Inactivation Counting and Choice Is a Stochastic Process: Evidence for Involvement of an X-Linked Activator](/preview/png/2037810.png)
SummaryFemale mammalian cells achieve dosage compensation of X-encoded genes by X chromosome inactivation (XCI). This process is thought to involve X chromosome counting and choice. To explore how this process is initiated, we analyzed XCI in tetraploid XXXX, XXXY, and XXYY embryonic stem cells and found that every X chromosome within a single nucleus has an independent probability to initiate XCI. This finding suggests a stochastic mechanism directing XCI counting and choice. The probability is directly proportional to the X chromosome:ploidy ratio, indicating the presence of an X-encoded activator of XCI, that itself is inactivated by the XCI process. Deletion of a region including Xist, Tsix, and Xite still results in XCI on the remaining wild-type X chromosome in female cells. This result supports a stochastic model in which each X chromosome in a nucleus initiates XCI independently and positions an X-encoded trans-acting XCI-activator outside the deleted region.
Journal: - Volume 132, Issue 3, 8 February 2008, Pages 410–421