Department of Biology of the Cell Nucleus, Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague, Czech Republic.
Department of Immunobiology, Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague, Czech Republic.
Cells. 2022 Jun 23;11(13):2013. doi: 10.3390/cells11132013.
The focal adhesion protein Vinculin (VCL) is ascribed to various cytoplasmic functions; however, its nuclear role has so far been ambiguous. We observed that VCL localizes to the nuclei of mouse primary spermatocytes undergoing first meiotic division. Specifically, VCL localizes along the meiosis-specific structure synaptonemal complex (SC) during prophase I and the centromeric regions, where it remains until metaphase I. To study the role of VCL in meiotic division, we prepared a conditional knock-out mouse (VCL). We found that the VCL male mice were semi-fertile, with a decreased number of offspring compared to wild-type animals. This study of events in late prophase I indicated premature splitting of homologous chromosomes, accompanied by an untimely loss of SCP1. This caused erroneous kinetochore formation, followed by failure of the meiotic spindle assembly and metaphase I arrest. To assess the mechanism of VCL involvement in meiosis, we searched for its possible interacting partners. A mass spectrometry approach identified several putative interactors which belong to the ubiquitin-proteasome pathway (UPS). The depletion of VLC leads to the dysregulation of a key subunit of the proteasome complex in the meiotic nuclei and an altered nuclear SUMOylation level. Taken together, we show for the first time the presence of VCL in the nucleus of spermatocytes and its involvement in proper meiotic progress. It also suggests the direction for future studies regarding the role of VCL in spermatogenesis through regulation of UPS.
粘着斑蛋白 Vinculin (VCL) 具有多种细胞质功能；然而，其核作用迄今为止仍不明确。我们观察到 VCL 定位于正在进行第一次减数分裂的小鼠初级精母细胞的核内。具体来说，VCL 在前期 I 沿减数特异性结构联会复合体 (SC) 定位，并在中期 I 之前保留在着丝粒区域。为了研究 VCL 在减数分裂中的作用，我们制备了条件性敲除小鼠 (VCL)。我们发现 VCL 雄性小鼠的半不育，与野生型动物相比，后代数量减少。这项对后期前期 I 事件的研究表明同源染色体过早分裂，同时 SCP1 过早丢失。这导致错误的动粒形成，随后减数纺锤体组装失败和中期 I 阻滞。为了评估 VCL 参与减数分裂的机制，我们搜索了其可能的相互作用伙伴。质谱分析鉴定了几种可能的相互作用蛋白，它们属于泛素-蛋白酶体途径 (UPS)。VCL 的耗竭导致减数分裂核中蛋白酶体复合物的关键亚基失调，并改变核 SUMOylation 水平。总之，我们首次证明了 VCL 存在于精母细胞的核内，并参与了减数分裂的正常进行。这也为未来关于 VCL 通过调节 UPS 在精子发生中的作用的研究指明了方向。
