CYK-4 functions independently of its centralspindlin partner ZEN-4 to cellularize oocytes in germline syncytia
CYK-4 functions independently of its centralspindlin partner ZEN-4 to cellularize oocytes in germline syncytia
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DOI：
10.7554/elife.36919
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发表时间：
2018-07-10
期刊：
影响因子：
7.7
通讯作者：
Oegema, Karen
中科院分区：
文献类型：
--
作者：
Lee, Kian-Yong;Green, Rebecca A.;Oegema, Karen
在整个后生动物中，生殖细胞经历不完全的胞质分裂形成合胞体，通过细胞间桥连接。配子的形成最终需要桥闭合，然而桥如何被重新激活以闭合尚不清楚。最保守的桥梁成分是中央纺锤子，它是Rho家族gtpase激活蛋白（GAP） CYK-4/MgcRacGAP和微管马达ZEN-4/kinesin-6的复合体。在这里，我们发现秀丽隐杆线虫的合胞生殖系产生卵母细胞需要CYK-4而不需要ZEN-4，这与细胞质分裂形成对比，两者都是必不可少的。条件失活后的纵向成像显示CYK-4活性对卵母细胞的细胞化很重要，但对产生合胞室的细胞动力学样事件并不重要。CYK-4的脂质结合C1结构域及其GAP结构域的gtpase结合界面都需要CYK-4靶向细胞间桥并使卵母细胞细胞化。这些结果表明CYK-4保守的C1-GAP区域构成了种系合胞体细胞间桥关闭所需的靶向模块。
Throughout metazoans, germ cells undergo incomplete cytokinesis to form syncytia connected by intercellular bridges. Gamete formation ultimately requires bridge closure, yet how bridges are reactivated to close is not known. The most conserved bridge component is centralspindlin, a complex of the Rho family GTPase-activating protein (GAP) CYK-4/MgcRacGAP and the microtubule motor ZEN-4/kinesin-6. Here, we show that oocyte production by the syncytial Caenorhabditis elegans germline requires CYK-4 but not ZEN-4, which contrasts with cytokinesis, where both are essential. Longitudinal imaging after conditional inactivation revealed that CYK-4 activity is important for oocyte cellularization, but not for the cytokinesis-like events that generate syncytial compartments. CYK-4's lipid-binding C1 domain and the GTPase-binding interface of its GAP domain were both required to target CYK-4 to intercellular bridges and to cellularize oocytes. These results suggest that the conserved C1-GAP region of CYK-4 constitutes a targeting module required for closure of intercellular bridges in germline syncytia.