Visualization of Inactive X Chromosome in Preimplantation Embryos Utilizing MacroH2A-EGFP Transgenic Mouse
Visualization of Inactive X Chromosome in Preimplantation Embryos Utilizing MacroH2A-EGFP Transgenic Mouse
复制标题
使用 MacroH2A-EGFP 转基因小鼠对植入前胚胎中失活 X 染色体进行可视化
作者：
楓馬淳美;佐藤建三;中西友子
在雌性真兽目哺乳动物中，两条X染色体中的一条失活。MacroH 2A是一种不寻常的组蛋白变体，已知在早期胚胎发育期间积累在无活性的X染色体（Xi）上，因此可以用作Xi的标记。在这项研究中，我们产生了一个转基因小鼠株系表达小鼠MacroH2A1.2增强的绿色荧光蛋白（EGFP）融合蛋白（MacroH 2A-EGFP）的CAG启动子的控制下，并验证MacroH 2A-EGFP是否将是有用的跟踪X染色体失活的过程中，通过可视化Xi非侵入性植入前胚胎。在转基因雌性小鼠中，MacroH 2A-EGFP在整个身体的细胞核中形成荧光焦点。在雌性胚泡中，MacroH 2A-EGFP焦点与Xist RNA共定位，Xist RNA众所周知是Xi的标志物。Xi的荧光标记首先在4-和8-细胞阶段之间的一些胚胎细胞中观察到。这些结果表明，MacroH 2A可以在雌性小鼠胚胎的8细胞期左右与Xi结合。这些MacroH 2A-EGFP转基因小鼠可能有助于阐明小鼠生命周期中X染色体失活的过程。创世纪51：259-267。© 2013 Wiley Periodicals，Inc.
One of the two X chromosomes is inactivated in female eutherian mammals. MacroH2A, an unusual histone variant, is known to accumulate on the inactive X chromosome (Xi) during early embryo development, and can thus be used as a marker of the Xi. In this study, we produced a transgenic mouse line expressing the mouse MacroH2A1.2–enhanced green fluorescent protein (EGFP) fusion protein (MacroH2A–EGFP) under the control of a CAG promoter and verified whether MacroH2A–EGFP would be useful for tracing the process of X chromosome inactivation by visualizing Xi noninvasively in preimplantation embryos. In transgenic female mice, MacroH2A–EGFP formed a fluorescent focus in nuclei throughout the body. In female blastocysts, the MacroH2A–EGFP focus colocalized with Xist RNA, well known as a marker of Xi. Fluorescence marking of Xi was first observed in some embryonic cells between the 4‐ and 8‐cell stages. These results demonstrate that MacroH2A can bind to the Xi by around the 8‐cell stage in female mouse embryos. These MacroH2A–EGFP transgenic mice might be useful to elucidate the process of X chromosome inactivation during the mouse life cycle. genesis 51:259–267. © 2013 Wiley Periodicals, Inc.