Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA.
Nat Struct Mol Biol. 2010 Aug;17(8):948-54. doi: 10.1038/nsmb.1877. Epub 2010 Jul 25.
One X chromosome, selected at random, is silenced in each female mammalian cell. Xist encodes a noncoding RNA that influences the probability that the cis-linked X chromosome will be silenced. We found that the A-repeat, a highly conserved element within Xist, is required for the accumulation of spliced Xist RNA. In addition, the A-repeat is necessary for X-inactivation to occur randomly. In combination, our data suggest that normal Xist RNA processing is important in the regulation of random X-inactivation. We propose that modulation of Xist RNA processing may be part of the stochastic process that determines which X chromosome will be inactivated.
在每个雌性哺乳动物细胞中，随机选择一条 X 染色体使其沉默。Xist 编码一种非编码 RNA，影响顺式连接的 X 染色体沉默的概率。我们发现，Xist 内高度保守的 A 重复序列对于拼接的 Xist RNA 的积累是必需的。此外，A 重复序列对于随机的 X 失活也是必需的。综合起来，我们的数据表明，正常的 Xist RNA 加工对于随机 X 失活的调节是很重要的。我们提出，Xist RNA 加工的调节可能是决定哪个 X 染色体失活的随机过程的一部分。
