研究人员发现,果蝇中去泛素酶USP8基因的缺失可以将生殖细胞的不完全分裂转化为完全分裂。相反,在生殖系干细胞中过量表达USP8足以实现从完全细胞分裂到不完全细胞分裂的反向转化。ESCRT-III蛋白CHMP2B和Shrub/CHMP4是USP8去泛素化活性的靶标。在Usp8突变的姐妹细胞中,ESCRT蛋白在细胞间桥上的异位募集导致囊破裂。一个不能被泛素化的Shrub/CHMP4变体不能在脱落桥上定位,导致不能完成脱落。这些结果揭示了ESCRT-III的泛素化是两种细胞分裂类型之间的主要开关。
据介绍,在许多脊椎动物和无脊椎动物中,配子是在由几轮不完全分裂形成的相互连接的细胞群中发育的,称为生殖囊。
附:英文原文
Title: The deubiquitinase USP8 targets ESCRT-III to promote incomplete cell division
Author: Juliette Mathieu, Pascale Michel-Hissier, Virginie Boucherit, Jean-René Huynh
Issue&Volume: 2022-05-20
Abstract: In many vertebrate and invertebrate organisms, gametes develop within groups of interconnected cells called germline cysts formed by several rounds of incomplete divisions. We found that loss of the deubiquitinase USP8 gene in Drosophila can transform incomplete divisions of germline cells into complete divisions. Conversely, overexpression of USP8 in germline stem cells is sufficient for the reverse transformation from complete to incomplete cytokinesis. The ESCRT-III proteins CHMP2B and Shrub/CHMP4 are targets of USP8 deubiquitinating activity. In Usp8 mutant sister cells, ectopic recruitment of ESCRT proteins at intercellular bridges causes cysts to break apart. A Shrub/CHMP4 variant that cannot be ubiquitinated does not localize at abscission bridges and cannot complete abscission. Our results uncover ubiquitination of ESCRT-III as a major switch between two types of cell division.
DOI: abg2653
Source: https://www.science.org/doi/10.1126/science.abg2653