5-azaC对人体成纤维细胞失活X染色体DNA复制带型的影响

本文用胞苷的类似物5-氮胞苷(5-azaC)处理两种人体皮肤成纤维细胞——46,XX和46,Xt(X;1)。经过一定时间培养,观察用5-azaC处理人体成纤维细胞中失活X染色体复制带的变化。发现5-azac对迟复制X(LX)和t(X;1)染色体上有一条或多条复制带的染色增深,表示复制提前,大约比对照组提前复制1小时左右。同时发现t(X;1)染色体上,受X失活中心的失活扩散影响的1-10区段,用5-azac处理之后,也有复制提前。复制提前这一现象,从另一方面支持了DNA甲基化,可能是人类X染色体失活的一种机理。

The Effect of 5-azaC on the Inactive X-chromosome Replication Bands of Human Fibroblasts

Two kinds of human skin fibroblasts-46XX and 46X,t(X;1)-were treated with a cy-tidine analog,5-azacytidine (5-azaC).After culturing for a definite time,the change of replication bands of inactive X-chro-mosome in human skin fibroblasts was observed.It showed that stain intensity on one or more bands in LX and t(X; 1) increased,and that the replication took place 1 hour earlier than the control.Moreover,it was seen that the replication on 1-10 region of t(X;l),influenced by the diffusion effect of inactive center on the late replicating X-chromosome,also happened earlier.These facts support the theory that metnylation may be a mechanism of human X-chromosome inactivition.