Page D C, Disteche C M, Simpson E M, de la Chapelle A, Andersson M, Alitalo T, Brown L G, Green P, Akots G
Whitehead Institute, Massachusetts Institute of Technology, Cambridge 02142.
Genomics. 1990 May;7(1):37-46. doi: 10.1016/0888-7543(90)90516-w.
The ZFY gene, found in the sex-determining region of the human Y chromosome, encodes a zinc-finger protein that may be the pivotal sex-determining signal. A closely related gene, ZFX, is found on the human X chromosome, and it may also function in sex determination. ZFX is one of a few genes on the human X chromosome that are known to escape X inactivation. We report the localization of ZFX, by meiotic linkage analysis and physical mapping, distal to POLA but proximal to DXS41 (p99-6), near the boundary of bands Xp21.3 and Xp22.1. (Our results suggest the following order of loci in Xp21-p22: cen-DMD-[GK,AHC]-DXS67 (pB24)-POLA-ZFX-[DXS41 (p99-6), DXS274 (CRI-L1391)]-DXS43 (pD2)-pter.) These findings contradict the model that escape from X inactivation is limited to genes near the short-arm telomere (i.e., in Xp22.3). Instead, escape from X inactivation is likely a property of several noncontiguous segments of the X chromosome. Curiously, in mouse, the homologous Zfx gene maps to X chromosome band D, near the center from which an X-inactivating signal is thought to spread. As judged by comparative mapping, it appears that an X-chromosomal segment that spans the ZFX and DMD genes has remained grossly intact during the divergence of mouse and human from a common ancestor. Conservation of this chromosomal segment may extent to marsupials, where homologs of the ZFX and DMD genes have been observed in proximity, but on an autosome. While autosomal homologs of ZFX have not been observed in other placental mammals, a locus derived from a processed Zfx transcript is found on mouse chromosome 10 band B3 or B4.
ZFY基因位于人类Y染色体的性别决定区域，编码一种锌指蛋白，该蛋白可能是关键的性别决定信号。在人类X染色体上发现了一个与之密切相关的基因ZFX，它可能也在性别决定中发挥作用。ZFX是人类X染色体上少数已知逃避X染色体失活的基因之一。我们通过减数分裂连锁分析和物理图谱绘制，报告了ZFX的定位，它位于POLA远端但DXS41（p99 - 6）近端，靠近Xp21.3和Xp22.1带的边界。（我们的结果表明Xp21 - p22中基因座的顺序如下：着丝粒 - DMD - [GK，AHC] - DXS67（pB24） - POLA - ZFX - [DXS41（p99 - 6），DXS274（CRI - L1391）] - DXS43（pD2） - 端粒。）这些发现与逃避X染色体失活仅限于短臂端粒附近（即Xp22.3）基因的模型相矛盾。相反，逃避X染色体失活可能是X染色体几个不连续片段的特性。奇怪的是，在小鼠中，同源的Zfx基因定位于X染色体带D，靠近据认为X染色体失活信号从其扩散的中心。通过比较图谱判断，在小鼠和人类从共同祖先分化过程中，跨越ZFX和DMD基因的X染色体片段似乎大体上保持完整。这个染色体片段的保守性可能延伸到有袋类动物，在那里观察到ZFX和DMD基因的同源物相邻，但位于常染色体上。虽然在其他胎盘哺乳动物中未观察到ZFX的常染色体同源物，但在小鼠染色体10带B3或B4上发现了一个源自加工后的Zfx转录本的基因座。
