Liskay R M, Evans R J
Proc Natl Acad Sci U S A. 1980 Aug;77(8):4895-8. doi: 10.1073/pnas.77.8.4895.
The molecular nature of the X chromosome inactivation process has been investigated by utilizing the techniques of DNA-mediated cell transformation of the X-linked hypoxanthine phosphoribosyltransferase (HPRT) locus. The findings indicate that purified DNA from the inactive X chromosome of a near-euploid mouse cell line is not functional in transformation for HPRT, but the DNA from its "homologous" active X readily elicits transformation for HPRT in the same hamster cell recipient. These findings suggest that there is a difference between the DNA, per se, of the active and inactive X at (or near) the HPRT locus and that this difference could account, at least in part, for its inactivation.
利用X连锁的次黄嘌呤磷酸核糖转移酶（HPRT）基因座的DNA介导细胞转化技术，对X染色体失活过程的分子本质进行了研究。研究结果表明，来自近整倍体小鼠细胞系失活X染色体的纯化DNA在HPRT转化中无功能，但来自其“同源”活性X染色体的DNA在相同的仓鼠细胞受体中能轻易引发HPRT转化。这些结果表明，在HPRT基因座（或其附近），活性X染色体和失活X染色体本身的DNA存在差异，且这种差异至少可以部分解释其失活现象。
