PLK4 is essential for meiotic resumption in mouse oocytes.
Polo-like kinase (PLK) 4 is a unique member of the PLK family that plays vital roles in centriole biogenesis during mitosis. The localization of PLK4 on centrioles must be precisely regulated during mitosis to ensure correct centriole duplication. However, little is known about the function of PLK4 in mammalian oocyte meiosis. We addressed this question by examining the expression and localization of PLK4 in mouse oocytes and using RNA interference and protein overexpression to investigate its function in meiosis. PLK4 expression peaked at the germinal vesicle breakdown (GVBD) stage, and the protein was localized in the cytoplasm throughout meiotic maturation. Depletion of PLK4 caused meiotic arrest at the GV stage and suppressed CYCLINB1 and CDC2 activities. Moreover, PLK4 depletion prevented the de-phosphorylation of CDC2-Tyr15 in nucleus and induced a decrease in the level of the CDC25C protein. PLK1 overexpression failed to rescue GV-stage arrest in PLK4-depleted oocytes, whereas overexpressing PLK4 resulted in normal GVBD in oocytes in which PLK1 activity was inhibited. In addition, PLK4 overexpression did not cause abnormal spindle formation or affect extrusion of the first polar body. These results illustrate the fact that PLK4 is essential for meiotic resumption but may not influence spindle formation in mouse oocytes during meiotic maturation.
Department of Animal Sciences, Chungbuk National University, Cheongju, Chungbuk, Republic of Korea.
Yi-Bo
YB
Luo
Department of Animal Sciences, Chungbuk National University, Cheongju, Chungbuk, Republic of Korea nhkim@chungbuk.ac.kr.
Nam-Hyung
NH
Kim
D000818:Animals; D016203:CDC2 Protein Kinase / Q000235:genetics; D002875:Chromosomes / Q000235:genetics; D005260:Female; D005306:Fertilization / Q000502:physiology; D066298:In Vitro Techniques; D008540:Meiosis / Q000502:physiology*; D051379:Mice; D009865:Oocytes / Q000502:physiology*; D010766:Phosphorylation; D010957:Plasmids / Q000235:genetics; D059705:Polar Bodies / Q000502:physiology; D011247:Pregnancy; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D008941:Spindle Apparatus; D020687:cdc25 Phosphatases / Q000235:genetics
D012333:RNA, Messenger; D034741:RNA, Small Interfering; C088051:Plk4 protein, mouse; D017346:Protein Serine-Threonine Kinases; D016203:CDC2 Protein Kinase; C517010:Cdc25c protein, mouse; D020687:cdc25 Phosphatases
PLK4; gamete biology; meiotic maturation; mouse; oocyte maturation