Bommi Jagadeeswara Rao, Rao Hanumanthu Bala Durga Prasada, Challa Kiran, Higashide Mika, Shinmyozu Kaori, Nakayama Jun-Ichi, Shinohara Miki, Shinohara Akira
Institute for Protein Research, Osaka University, Suita, Osaka, Japan.
RIKEN Center for Developmental Biology, Kobe, Japan.
Genes Cells. 2019 Jan;24(1):94-106. doi: 10.1111/gtc.12653. Epub 2018 Dec 12.
Proteins in the nuclear envelope (NE) play a role in the dynamics and functions of the nucleus and of chromosomes during mitosis and meiosis. Mps3, a yeast NE protein with a conserved SUN domain, predominantly localizes on a yeast centrosome equivalent, spindle pole body (SPB), in mitotic cells. During meiosis, Mps3, together with SPB, forms a distinct multiple ensemble on NE. How meiosis-specific NE localization of Mps3 is regulated remains largely unknown. In this study, we found that a meiosis-specific component of the protein complex essential for sister chromatid cohesion, Rec8, binds to Mps3 during meiosis and controls Mps3 localization and proper dynamics on NE. Ectopic expression of Rec8 in mitotic yeast cells induced the formation of Mps3 patches/foci on NE. This required the cohesin regulator, WAPL ortholog, Rad61/Wpl1, suggesting that a meiosis-specific cohesin complex with Rec8 controls NE localization of Mps3. We also observed that two domains of the nucleoplasmic region of Mps3 are essential for NE localization of Mps3 in mitotic as well as meiotic cells. We speculate that the interaction of Mps3 with the meiosis-specific cohesin in the nucleoplasm is a key determinant for NE localization/function of Mps3.
核膜（NE）中的蛋白质在有丝分裂和减数分裂过程中，对细胞核及染色体的动态变化和功能发挥着作用。Mps3是一种具有保守SUN结构域的酵母核膜蛋白，在有丝分裂细胞中主要定位于酵母中心体等价物——纺锤体极体（SPB）上。在减数分裂过程中，Mps3与SPB一起在核膜上形成独特的多个集合体。Mps3在减数分裂过程中特异性定位于核膜的调控机制在很大程度上仍不清楚。在本研究中，我们发现一种对姐妹染色单体黏连至关重要的蛋白质复合物的减数分裂特异性成分Rec8，在减数分裂过程中与Mps3结合，并控制Mps3在核膜上的定位和正常动态变化。在有丝分裂酵母细胞中异位表达Rec8会诱导Mps3在核膜上形成斑块/聚集点。这需要黏连蛋白调节因子、WAPL直系同源物Rad61/Wpl1参与，表明含有Rec8的减数分裂特异性黏连蛋白复合物控制着Mps3在核膜上的定位。我们还观察到，Mps3核质区域的两个结构域对于其在有丝分裂和减数分裂细胞中定位于核膜至关重要。我们推测，Mps3在核质中与减数分裂特异性黏连蛋白的相互作用是决定Mps3在核膜上定位/功能的关键因素。
