The Histone H2A Variant MacroH2A1 Does Not Localize to the Centrosome

MacroH2A1 is a histone H2A variant which contains a large non-histone C-terminal region of largely unknown function. Within this region is a macro domain which can bind ADP-ribose and related molecules. Most studies of macroH2A1 focus on the involvement of this variant in transcriptional repression. Studies in mouse embryos and in embryonic stem cells suggested that during early development macroH2A can be found at the centrosome. Centrosomal localization of macroH2A was later reported in somatic cells. Here we provide data showing that macroH2A1 does not localize to the centrosome and that the centrosomal signal observed with antibodies directed against the macroH2A1 non-histone region may be the result of antibody cross-reactivity.宏组蛋白H2A1（MacroH2A1）是一种组蛋白H2A变体（histone H2A variant），其含有一个庞大的非组蛋白C端区域，该区域的功能大多尚未明确。该区域内存在一个宏结构域（macro domain），可结合ADP-核糖（ADP-ribose）及其相关分子。目前针对宏组蛋白H2A1的多数研究均聚焦于该变体在转录抑制中的作用。针对小鼠胚胎与胚胎干细胞的研究表明，在早期发育阶段，宏组蛋白H2A可定位于中心体（centrosome）；后续又有研究报道称体细胞中也存在宏组蛋白H2A的中心体定位现象。本研究提供的数据显示，宏组蛋白H2A1并不会定位于中心体，而此前针对宏组蛋白H2A1非组蛋白区域的抗体所观测到的中心体信号，可能源于抗体的交叉反应（antibody cross-reactivity）。