Heard E, Simmler M C, Larin Z, Rougeulle C, Courtier B, Lehrach H, Avner P
Unité de Génétique Moléculaire Murine, Institut Pasteur, Paris, France.
Genomics. 1993 Mar;15(3):559-69. doi: 10.1006/geno.1993.1108.
The Xist sequence has been proposed as a potential candidate for the X-inactivation center based both on its localization within the candidate region for the X-inactivation center in man and mouse and on its unique pattern of expression from the inactive X chromosome. We have cloned 550 kb of DNA surrounding the mouse Xist sequence in contiguously overlapping YAC clones and have developed a long-range restriction map that spans almost 1 Mb of this region and includes this YAC contig. The detailed restriction map we have established provides a framework for the identification of expressed sequences other than Xist that may equally exhibit unusual expression characteristics associated with X inactivation. The presence of possible structural or methylation differences within this region between the active and inactive X chromosomes has been investigated through comparative analysis of male and female genomic DNA, and we report here the identification of certain CpG-containing restriction sites around Xist that have an interesting differential methylation status on the inactive and active X chromosomes.
基于Xist序列在人和小鼠X染色体失活中心候选区域内的定位，以及其从不活跃X染色体上独特的表达模式，该序列已被提议作为X染色体失活中心的潜在候选序列。我们在连续重叠的酵母人工染色体（YAC）克隆中克隆了围绕小鼠Xist序列的550 kb DNA，并绘制了一个跨越该区域近1 Mb的长程限制性图谱，其中包括这个YAC重叠群。我们建立的详细限制性图谱为鉴定除Xist之外可能同样表现出与X染色体失活相关的异常表达特征的表达序列提供了一个框架。通过对雄性和雌性基因组DNA的比较分析，研究了该区域内活跃和不活跃X染色体之间可能存在的结构或甲基化差异，我们在此报告在Xist周围鉴定出某些含CpG的限制性位点，它们在不活跃和活跃X染色体上具有有趣的差异甲基化状态。
