Heard E, Clerc P, Avner P
Unité de Génétique Moléculaire Murine, URA CNRS 1968, Institut Pasteur, Paris, France.
Annu Rev Genet. 1997;31:571-610. doi: 10.1146/annurev.genet.31.1.571.
The inactive X chromosome differs from the active X in a number of ways; some of these, such as allocyclic replication and altered histone acetylation, are associated with all types of epigenetic silencing, whereas others, such as DNA methylation, are of more restricted use. These features are acquired progressively by the inactive X after onset of initiation. Initiation of X-inactivation is controlled by the X-inactivation center (Xic) and influenced by the X chromosome controlling element (Xce), which causes primary nonrandom X-inactivation. Other examples of nonrandom X-inactivation are also presented in this review. The definition of a major role for Xist, a noncoding RNA, in X-inactivation has enabled investigation of the mechanism leading to establishment of the heterochromatinized X-chromosome and also of the interactions between X-inactivation and imprinting as well as between X-inactivation and developmental processes in the early embryo.
失活的X染色体在许多方面与活性X染色体不同；其中一些，如异时复制和组蛋白乙酰化改变，与所有类型的表观遗传沉默有关，而其他一些，如DNA甲基化，则用途更为有限。这些特征在起始后由失活的X染色体逐渐获得。X染色体失活的起始由X染色体失活中心（Xic）控制，并受X染色体控制元件（Xce）影响，后者导致初级非随机X染色体失活。本综述中还介绍了非随机X染色体失活的其他例子。非编码RNA Xist在X染色体失活中起主要作用的定义，使得人们能够研究导致异染色质化X染色体形成的机制，以及X染色体失活与印记之间的相互作用，以及X染色体失活与早期胚胎发育过程之间的相互作用。
