摘要
剂量补偿是使Ｘ连锁基因的表达水平在两性间达到平衡的过程。生物界实现剂量补偿的策略有很多种，真兽亚纲哺乳动物是随机失活雌性的一条Ｘ染色体。Ｘ失活开始于ＸＩＣ，然后传播到整条染色体。ＸＩＳＴ基因定位于ＸＩＣ中，参与Ｘ失活的启动，可能是Ｘ失活决定基因。最近在人和小鼠中发现了逃避Ｘ失活的基因。探讨这些基因逃避Ｘ失活的机制有助于理解Ｘ染色体失活是如何对基因表达进行调控的。人和小鼠中有一些基因的Ｘ失活状态不同。
Dosage compensation is the process by which the levels of X linked gene expression is equalized between the sexes. The strategies used to accomplish dosage compensation are varied. In eutherian mammals,dosage compensation is achived by random inactivating one of the two X chromosomes in the female. X inactivation starts at the X inactivation center(XIC) and spreads throughout the chromosome. The XIST gene maps to the XIC region on the mouse and human X chromosome and is thought to be involved in the initiation of inactivation,making it a strong candidate for XIC itself. The genes that escape X inactivation have been recently found in human and in mouse. Study on the mechanisms of ‘escape’ is helpful to the understanding of gene regulation by X inactivation. The Xinactivation status of some genes differs significantly between human and mouse,suggesting continuous evolutionary changes in the sex chromosomes.
出处
《生物工程进展》
CSCD
1997年第3期39-43,共5页
Progress in Biotechnology
关键词
性别决定
剂量补偿
X染色体失活
基因调控
进化
Sex determination
Dosage compensation
X inactivation
Gene regulation
Evolution
