X‐chromosome inactivation and human genetic disease
X‐chromosome inactivation and human genetic disease
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DOI：
10.1111/j.1651-2227.2002.tb03120.x
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发表时间：
2002-11
期刊：
影响因子：
--
通讯作者：
MF Lyon
中科院分区：
文献类型：
--
作者：
MF Lyon
女性在早期发育过程中一条X染色体失活是XX女性和XY男性之间X连锁基因的有效剂量相等的过程。造成这种情况的机制是深入研究的主题。 X 连锁基因 Xist 是一个关键角色，对于 X 失活的启动是必要的，但还不够。它编码一种覆盖非活性 X 染色体的非翻译 RNA，该染色体具有异染色质的特性，但染色质的这种变化是如何引起的仍不清楚。由于 X 失活，X 连锁基因杂合的雌性是两种类型细胞的混合物，并表现出可变的表型。由于组织或整个生物体水平上的细胞选择，两种类型细胞的比例可能会不一致。在极少数情况下，Xist 基因的变化可能会导致 X 失活的偏差。一些基因完全或部分逃脱了 X 失活。
The inactivation of one X‐chromosome in females in early development is the process by which the effective dosage of X‐linked genes is equalized between XX females and XY males. The mechanism that brings this about is the subject of intense research. The X‐linked gene Xist is a key player, which is necessary but not sufficient for the initiation of X‐inactivation. It codes for an untranslated RNA that coats the inactive X‐chromosome, which takes on properties characteristic of heterochromatin, but how this change in chromatin is brought about remains unknown. Because of X‐inactivation, females heterozygous for X‐linked genes are mixtures of two types of cells and show a variable phenotype. The proportion s of the two types of cells can depart from equality due to cell selection either at the tissue or whole organism level. In rare cases, changes in the Xist gene can cause skewing of X‐inactivation. A few genes escape from X‐inactivation either wholly or partially.