Molecular basis and functional significance of XY body formation in mammalian male meiosis

XY体是哺乳动物雄性减数分裂过程中在性染色体上形成的特殊异色结构。XY小体形成失败导致精母细胞凋亡，提示其在雄性配子发生中的重要作用。然而，迄今为止，XY体形成的分子基础在很大程度上是未知的。在这项研究中，我们使用基因靶向技术产生了缺乏HORMAD2的小鼠，HORMAD2是一种定位于小鼠精母细胞性染色体轴的蛋白质。我们的研究结果表明，HORMAD2通过募集ATR活性对XY体的形成至关重要。

The XY body is a specialized heterochromatic structure formed on the sex chromosomes during mammalian male meiosis. The failure of XY body formation leads to spermatocyte apoptosis, suggesting its crucial function in male gametogenesis. To date, however, the molecular basis of XY body formation has been largely unknown. In this study, we used gene targeting to generate mice lacking HORMAD2, a protein that localizes to the sex chromosome axes in mouse spermatocytes. Our results reveal that HORMAD2 is essential for the XY body formation via the recruitment of ATR activity.