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Small GTPase RhoA is required for ooplasmic segregation and spindle rotation, but not for spindle organization and chromosome separation during mouse oocyte maturation, fertilization, and early cleavage
Author(s) -
Zhong ZhiSheng,
Huo LiJun,
Liang ChengGuang,
Chen DaYuan,
Sun QingYuan
Publication year - 2005
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.20253
Subject(s) - rhoa , microbiology and biotechnology , biology , germinal vesicle , cytokinesis , cleavage furrow , midbody , spindle apparatus , small gtpase , telophase , spindle pole body , polar body , anaphase , centrosome , oocyte , cell division , genetics , cell cycle , cell , signal transduction , embryo
RhoA, a small GTPase, plays versatile roles in many aspects of cell function such as stress fiber formation, cytokinesis, and cell polarization. In this study, we investigated the subcellular localization of RhoA and its possible roles during oocyte maturation and fertilization. RhoA was localized in the cytoplasm of eggs from the germinal vesicle (GV) stage to 2‐cell stage, especially concentrating in the midbody of telophase spindle when oocyte extruded PB1 and PB2. The RhoA kinases (ROCKs) specific inhibitor Y‐27632 blocked GV breakdown (GVBD) and first polar body extrusion, but did not affect apparatus formation and anaphase/telophase I entry. Anti‐RhoA antibody microinjection into the oocytes showed similar results. RhoA inhibitor caused abnormal organization of microfilaments, failure of spindle rotation, PB2 extrusion as well as cleavage furrow formation, while sister chromatid separation was not affected. Microinjection of RhoA antibody also blocked PB2 emission. Our findings indicate that RhoA, by regulating microfilament organization, regulates several important events including GVBD, polar body emission, spindle rotation, and cleavage. Mol. Reprod. Dev. 71: 256–261, 2005. © 2005 Wiley‐Liss, Inc.