RanGTP and importin beta regulate meiosis I spindle assembly and function in mouse oocytes

0523991 - ÚŽFG 2021 RIV GB eng J - Journal Article
Drutovič, Dávid - Duan, X. - Li, R. - Kaláb, P. - Šolc, Petr
RanGTP and importin beta regulate meiosis I spindle assembly and function in mouse oocytes.
EMBO Journal. Roč. 39, č. 1 (2020), č. článku e101689. ISSN 0261-4189. E-ISSN 1460-2075
R&D Projects: GA MŠMT(CZ) LO1609
Institutional support: RVO:67985904
Keywords : importazole * importin beta * meiosis I * oocyte * RanGTP
OECD category: Cell biology
Impact factor: 11.598, year: 2020
Method of publishing: Limited access
https://asep.lib.cas.cz/arl-cav/cs/csg/?repo=crepo1&key=76358145974

Homologous chromosome segregation during meiosis I (MI) in mammalian oocytes is carried out by the acentrosomal MI spindles. Whereas studies in human oocytes identified Ran GTPase as a crucial regulator of the MI spindle function, experiments in mouse oocytes questioned the generality of this notion. Here, we use live-cell imaging with fluorescent probes and Forster resonance energy transfer (FRET) biosensors to monitor the changes in Ran and importin beta signaling induced by perturbations of Ran in mouse oocytes while examining the MI spindle dynamics. We show that unlike RanT24N employed in previous studies, a RanT24N, T42A double mutant inhibits RanGEF without perturbing cargo binding to importin beta and disrupts MI spindle function in chromosome segregation. Roles of Ran and importin beta in the coalescence of microtubule organizing centers (MTOCs) and MI spindle assembly are further supported by the use of the chemical inhibitor importazole, whose effects are partially rescued by the GTP hydrolysis-resistant RanQ69L mutant. These results indicate that RanGTP is essential for MI spindle assembly and function both in humans and mice.
Permanent Link: http://hdl.handle.net/11104/0308307