title: RhoA-mediated MLC2 regulates actin dynamics for cytokinesis in meiosis.
abstract: During oocyte meiosis, the bipolar spindle forms in the central cytoplasm and then migrates to the cortex. Subsequently, the oocyte extrudes the polar body through two successive asymmetric divisions, which are regulated primarily by actin filaments. Myosin light chain2 (MLC2) phosphorylation plays pivotal roles in smooth muscle contraction, stress fiber formation, cell motility and cytokinesis. However, whether MLC2 phosphorylation participates in the oocyte polarization and asymmetric division has not been clarified. The present study investigated the expression and functions of MLC2 during mouse oocyte meiosis. Our result showed that p-MLC2 was localized in the oocyte cortex, with a thickened cap above the chromosomes. Meanwhile, p-MLC2 was also localized in the poles of spindle. Disruption of MLC2 activity by MLC2 knock down (KD) caused the failure of polar body extrusion. Immunofluorescent staining showed that a large proportion of oocytes arrested in telophase stage and failed to undergo cytokinesis after culturing for 12 hours. In the meantime, actin filament staining at oocyte membrane and cytoplasm were reduced in MLC2 KD oocytes. Finally, we found that the phosphorylation of MLC2 protein levels was decreased after disruption of RhoA activity. Above all, our data indicated that the RhoA-mediated MLC2 regulates the actin organization for cytokinesis during mouse oocyte maturation.
authors.affiliation: a College of Animal Science and Technology, Nanjing Agricultural University , Nanjing , China.
authors.forename: Xing
authors.initials: X
authors.lastname: Duan
authors.affiliation: a College of Animal Science and Technology, Nanjing Agricultural University , Nanjing , China.
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.affiliation: a College of Animal Science and Technology, Nanjing Agricultural University , Nanjing , China.
authors.forename: Cheng-Cheng
authors.initials: CC
authors.lastname: Zhu
authors.affiliation: a College of Animal Science and Technology, Nanjing Agricultural University , Nanjing , China.
authors.forename: Qiao-Chu
authors.initials: QC
authors.lastname: Wang
authors.affiliation: b Department of Animal Sciences , Chungbuk National University , Cheongju , Korea.
authors.forename: Xiang-Shun
authors.initials: XS
authors.lastname: Cui
authors.affiliation: b Department of Animal Sciences , Chungbuk National University , Cheongju , Korea.
authors.forename: Nam-Hyung
authors.initials: NH
authors.lastname: Kim
authors.affiliation: a College of Animal Science and Technology, Nanjing Agricultural University , Nanjing , China.
authors.forename: Bo
authors.initials: B
authors.lastname: Xiong
authors.affiliation: a College of Animal Science and Technology, Nanjing Agricultural University , Nanjing , China.
authors.forename: Shao-Chen
authors.initials: SC
authors.lastname: Sun
mesh_terms: D000199:Actins / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D048749:Cytokinesis / Q000187:drug effects; D008540:Meiosis; D051379:Mice; D018613:Microscopy, Confocal; D018994:Myosin Light Chains / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D009866:Oogenesis; D009930:Organic Chemicals / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D059705:Polar Bodies; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013692:Telophase; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
chemical_list: D000199:Actins; C521958:Mylpf protein, mouse; D018994:Myosin Light Chains; D009930:Organic Chemicals; D034741:RNA, Small Interfering; C586690:rhosin; D020742:rhoA GTP-Binding Protein
keywords: Actin; MLC2; cytokinesis; meiosis; polar body extrusion