Abstract：
BACKGROUND: Inhibitors of DNA binding (ID) proteins mainly inhibit gene expression and regulate cell fate decisions by interacting with E-proteins. All four ID proteins (ID1-4) are present in the testis, and ID4 has a particularly important role in spermatogonial stem cell fate determination. Several lines of evidence indicate that ID proteins are involved in meiosis; however, functional experiments have not been conducted to validate this observation.
RESULTS: In this study, we report that ID2 is enriched in spermatocytes and that forced ID2 expression in germ cells causes defects in spermatogenesis. A detailed analysis demonstrated that Id2 overexpression (Id2 OE) decreased the total number of spermatogonia and changed the dynamics of meiosis progression. Specifically, spermatocytes were enriched in the zygotene stage, and the proportion of pachytene spermatocytes was significantly decreased, indicating defects in the zygotene-pachytene transition. The number of MLH1-positive foci per cell was decreased in pachytene spermatocytes from Id2 OE testes, suggesting abnormalities in recombination. Transcriptome analysis revealed that forced Id2 expression changed the expression of a list of genes mainly associated with meiosis and spermatid development.
CONCLUSIONS: ID2 protein is expressed in spermatocytes, and its genetic ablation in the germline does not affect spermatogenesis, likely due to genetic compensation of its family members. However, forced Id2 expression changes meiosis progression and causes defects in spermiogenesis. These data provide important evidence that ID proteins play pivotal roles in male meiosis and spermatid development.
RESULTS: In this study, we report that ID2 is enriched in spermatocytes and that forced ID2 expression in germ cells causes defects in spermatogenesis. A detailed analysis demonstrated that Id2 overexpression (Id2 OE) decreased the total number of spermatogonia and changed the dynamics of meiosis progression. Specifically, spermatocytes were enriched in the zygotene stage, and the proportion of pachytene spermatocytes was significantly decreased, indicating defects in the zygotene-pachytene transition. The number of MLH1-positive foci per cell was decreased in pachytene spermatocytes from Id2 OE testes, suggesting abnormalities in recombination. Transcriptome analysis revealed that forced Id2 expression changed the expression of a list of genes mainly associated with meiosis and spermatid development.
CONCLUSIONS: ID2 protein is expressed in spermatocytes, and its genetic ablation in the germline does not affect spermatogenesis, likely due to genetic compensation of its family members. However, forced Id2 expression changes meiosis progression and causes defects in spermiogenesis. These data provide important evidence that ID proteins play pivotal roles in male meiosis and spermatid development.
摘要：
背景：DNA结合（ID）蛋白抑制剂主要通过与E蛋白相互作用来抑制基因表达并调节细胞命运决定。所有四种ID蛋白（ID1-4）都存在于睾丸中，ID4在精原干细胞命运决定中具有特别重要的作用。一些证据表明ID蛋白参与减数分裂;然而，尚未进行功能实验来验证这一观察结果。
结果：在这项研究中，我们报告说，精母细胞中ID2富集，生殖细胞中ID2的强制表达会导致精子发生缺陷。详细的分析表明，Id2过表达（Id2OE）降低了精原细胞的总数，并改变了减数分裂进程的动力学。具体来说,精母细胞在合子阶段富集，粗线质精母细胞的比例显著下降，表明合子-粗线质过渡的缺陷。来自Id2OE睾丸的粗线精母细胞中每个细胞的MLH1阳性灶数量减少，提示重组异常。转录组分析显示，强制Id2表达改变了一系列主要与减数分裂和精子细胞发育相关的基因的表达。
结论：ID2蛋白在精母细胞中表达，它在种系中的遗传消融不会影响精子发生，可能是由于其家庭成员的遗传补偿。然而,强制性Id2表达改变减数分裂进程并导致精子形成缺陷。这些数据提供了重要证据，表明ID蛋白在男性减数分裂和精子细胞发育中起关键作用。
结果：在这项研究中，我们报告说，精母细胞中ID2富集，生殖细胞中ID2的强制表达会导致精子发生缺陷。详细的分析表明，Id2过表达（Id2OE）降低了精原细胞的总数，并改变了减数分裂进程的动力学。具体来说,精母细胞在合子阶段富集，粗线质精母细胞的比例显著下降，表明合子-粗线质过渡的缺陷。来自Id2OE睾丸的粗线精母细胞中每个细胞的MLH1阳性灶数量减少，提示重组异常。转录组分析显示，强制Id2表达改变了一系列主要与减数分裂和精子细胞发育相关的基因的表达。
结论：ID2蛋白在精母细胞中表达，它在种系中的遗传消融不会影响精子发生，可能是由于其家庭成员的遗传补偿。然而,强制性Id2表达改变减数分裂进程并导致精子形成缺陷。这些数据提供了重要证据，表明ID蛋白在男性减数分裂和精子细胞发育中起关键作用。
