Matias Neuza Reis, Mathieu Juliette, Huynh Jean-René
Department of Genetics and Developmental Biology, Institut Curie, Paris, France; CNRS UMR3215, Inserm U934, Paris, France.
PLoS Genet. 2015 Feb 3;11(2):e1004653. doi: 10.1371/journal.pgen.1004653. eCollection 2015 Feb.
Abscission is the final event of cytokinesis that leads to the physical separation of the two daughter cells. Recent technical advances have allowed a better understanding of the cellular and molecular events leading to abscission in isolated yeast or mammalian cells. However, how abscission is regulated in different cell types or in a developing organism remains poorly understood. Here, we characterized the function of the ESCRT-III protein Shrub during cytokinesis in germ cells undergoing a series of complete and incomplete divisions. We found that Shrub is required for complete abscission, and that levels of Shrub are critical for proper timing of abscission. Loss or gain of Shrub delays abscission in germline stem cells (GSCs), and leads to the formation of stem-cysts, where daughter cells share the same cytoplasm as the mother stem cell and cannot differentiate. In addition, our results indicate a negative regulation of Shrub by the Aurora B kinase during GSC abscission. Finally, we found that Lethal giant discs (lgd), known to be required for Shrub function in the endosomal pathway, also regulates the duration of abscission in GSCs.
细胞分裂末期是胞质分裂的最后一步，它导致两个子细胞的物理分离。最近的技术进步使人们能够更好地理解在分离的酵母或哺乳动物细胞中导致细胞分裂末期的细胞和分子事件。然而，细胞分裂末期在不同细胞类型或发育中的生物体中是如何被调控的，仍然知之甚少。在这里，我们描述了ESCRT-III蛋白Shrub在经历一系列完整和不完整分裂的生殖细胞胞质分裂过程中的功能。我们发现Shrub是完全细胞分裂末期所必需的，并且Shrub的水平对于细胞分裂末期的正确时间至关重要。Shrub的缺失或增加会延迟生殖系干细胞（GSCs）的细胞分裂末期，并导致形成干细胞囊肿，其中子细胞与母干细胞共享相同的细胞质且无法分化。此外，我们的结果表明在GSC细胞分裂末期Aurora B激酶对Shrub有负调控作用。最后，我们发现已知在内体途径中Shrub功能所必需的致死性大圆盘蛋白（lgd）也调节GSCs细胞分裂末期的持续时间。
