Graves J A, Gartler S M
Somat Cell Mol Genet. 1986 May;12(3):275-80. doi: 10.1007/BF01570786.
Mammalian X chromosome inactivation is generally considered to be a good example of stable transcriptional repression; however, there has been no satisfactory evidence for transcriptional control. We have made a test of the hypothesis of transcriptional control by Northern blot analysis of RNA from a woman heterozygous for a mutant Hpt allele which shows no detectable transcription of wild-type mRNA. Cells from this Hpt+ Hpt- woman were separated into HPRT+ and HPRT- subpopulations by selection in HAT or thioguanine. The HPRT+ population (in which the Hpt+ is on the active X) transcribed normal Hpt mRNA, while the HPRT- population (in which the Hpt+ allele is on the inactive X) did not. These results provide strong support for the hypothesis of transcriptional control.
哺乳动物X染色体失活通常被认为是稳定转录抑制的一个很好的例子；然而，目前尚无关于转录控制的令人满意的证据。我们通过对一名杂合了突变型磷酸丙糖异构酶（Hpt）等位基因的女性的RNA进行Northern印迹分析，对转录控制假说进行了检验，该突变型等位基因未检测到野生型mRNA的转录。通过在次黄嘌呤-氨基蝶呤-胸腺嘧啶核苷（HAT）或硫鸟嘌呤中进行选择，将这名Hpt+ Hpt-女性的细胞分离为次黄嘌呤鸟嘌呤磷酸核糖转移酶（HPRT）阳性和阴性亚群。HPRT阳性群体（其中Hpt+位于活性X染色体上）转录正常的Hpt mRNA，而HPRT阴性群体（其中Hpt+等位基因位于失活X染色体上）则不转录。这些结果为转录控制假说提供了有力支持。
