Kerem B S, Kottusch-Geiseler V, Kalscheuer V, Goitein R, Sperling K, Marcus M
Department of Genetics, Hebrew University, Jerusalem, Israel.
Chromosoma. 1988;96(3):227-30. doi: 10.1007/BF00302362.
We isolated Microtus agrestis-mouse somatic cell hybrid clones which had retained either the active or the inactive M. agrestis X chromosome. In both hybrid clones the X chromosomes retained their original chromatin conformation as studied by the in situ nick translation technique--the active X chromosome retained its high sensitivity to DNase I while the inactive one remained insensitive. A clone in which the hypoxanthine guanine phosphoribosyltransferase (HPRT) gene had been spontaneously reactivated was isolated from the hybrid containing the inactive X chromosome. The in situ nick translation technique was used to study possible DNA conformation changes in the euchromatin of the inactive X chromosome with special reference to the reactivated HPRT locus. We found that the euchromatin in this X chromosome exhibited the same low sensitivity to DNase I as is characteristic of the inactive X chromosome.
我们分离出了田鼠 - 小鼠体细胞杂交克隆，这些克隆保留了活跃或不活跃的田鼠X染色体。通过原位缺口平移技术研究发现，在这两种杂交克隆中，X染色体都保留了其原始的染色质构象——活跃的X染色体对DNase I保持高敏感性，而不活跃的X染色体则不敏感。从含有不活跃X染色体的杂交细胞中分离出一个次黄嘌呤鸟嘌呤磷酸核糖转移酶（HPRT）基因自发重新激活的克隆。原位缺口平移技术被用于研究不活跃X染色体常染色质中可能的DNA构象变化，特别关注重新激活的HPRT基因座。我们发现，这条X染色体中的常染色质对DNase I表现出与不活跃X染色体相同的低敏感性。
