title: WAVE2 regulates meiotic spindle stability, peripheral positioning and polar body emission in mouse oocytes.
abstract: During oocyte meiotic maturation, meiotic spindles form in the central cytoplasm and then migrate to the cortex to extrude a small polar body, forming a highly polarized cell through a process involving actin and actin-related molecules. The mechanisms underlying oocyte polarization are still unclear. The Arp2/3 complex regulates oocyte polarization but it is not known whether the WASP family of proteins, a known regulator of the Arp2/3 complex, is involved in this context. In the present study, the role of WASP family member WAVE2 in mouse oocyte asymmetric division was investigated. (1) WAVE2 mRNA and protein were detected during mouse oocyte meiosis. (2) siRNA-mediated and antibody-mediated disruption of WAVE2 resulted in the failure of chromosome congression, spindle formation, spindle positioning and polar body extrusion. (3) WAVE2 regulated actin-driven chromosome migration since chromosomes were arrested in the central cytoplasm by WAVE2 RNAi in the absence of microtubules. (4) Localization of γ-tubulin and MAPK was disrupted after RNAi, confirming the effect of WAVE2 on spindle formation. (5) Actin cap and cortical granule-free domain (CGFD) formation was also disrupted, further confirming the failure of oocyte polarization. Our data suggest that WAVE2 regulates oocyte polarization by regulating meiotic spindle, peripheral positioning, probably via an actin-mediated pathway, and is involved in polar body emission during mouse oocyte meiotic maturation.
authors.affiliation: Chungbuk National University; Cheongju, Korea.
authors.forename: Shao-Chen
authors.initials: SC
authors.lastname: Sun
authors.forename: Yong-Nan
authors.initials: YN
authors.lastname: Xu
authors.forename: Ying-Hua
authors.initials: YH
authors.lastname: Li
authors.forename: Seung-Eun
authors.initials: SE
authors.lastname: Lee
authors.forename: Yong-Xun
authors.initials: YX
authors.lastname: Jin
authors.forename: Xiang-Shun
authors.initials: XS
authors.lastname: Cui
authors.forename: Nam-Hyung
authors.initials: NH
authors.lastname: Kim
mesh_terms: D000199:Actins / Q000502:physiology; D000818:Animals; D016764:Cell Polarity; D002875:Chromosomes / Q000378:metabolism; D003599:Cytoskeleton / Q000502:physiology; D008540:Meiosis; D051379:Mice; D009865:Oocytes / Q000166:cytology*; D051300:Wiskott-Aldrich Syndrome Protein Family / Q000502:physiology*
chemical_list: D000199:Actins; C492303:Wasf2 protein, mouse; D051300:Wiskott-Aldrich Syndrome Protein Family