Borsani G, Tonlorenzi R, Simmler M C, Dandolo L, Arnaud D, Capra V, Grompe M, Pizzuti A, Muzny D, Lawrence C, Willard H F, Avner P, Ballabio A
Department of Cell Biology, Baylor College of Medicine, Houston, Texas 77030.
Nature. 1991 May 23;351(6324):325-9. doi: 10.1038/351325a0.
In mammals, equal dosage of gene products encoded by the X chromosome in male and female cells is achieved by X inactivation. Although X-chromosome inactivation represents the most extensive example known of long range cis gene regulation, the mechanism by which thousands of genes on only one of a pair of identical chromosomes are turned off is poorly understood. We have recently identified a human gene (XIST) exclusively expressed from the inactive X chromosome. Here we report the isolation and characterization of its murine homologue (Xist) which localizes to the mouse X inactivation centre region and is the first murine gene found to be expressed from the inactive X chromosome. Nucleotide sequence analysis indicates that Xist may be associated with a protein product. The similar map positions and expression patterns for Xist in mouse and man suggest that this gene may have a role in X inactivation.
在哺乳动物中，通过X染色体失活可使雄性和雌性细胞中X染色体所编码的基因产物剂量相等。尽管X染色体失活是已知的远距离顺式基因调控的最广泛例子，但对于一对同源染色体中仅一条上的数千个基因被关闭的机制，我们却知之甚少。我们最近鉴定出一个仅在失活的X染色体上表达的人类基因（XIST）。在此，我们报告其小鼠同源物（Xist）的分离和特性，该同源物定位于小鼠X染色体失活中心区域，是首个被发现从失活的X染色体上表达的小鼠基因。核苷酸序列分析表明，Xist可能与一种蛋白质产物相关。Xist在小鼠和人类中的相似图谱位置及表达模式表明，该基因可能在X染色体失活中发挥作用。
