Involvement of calcium/calmodulin-dependent protein kinase kinase in meiotic maturation of pig oocytes.
Calcium (Ca(2+))/calmodulin-dependent protein kinase kinase (CaMKK) is a novel member of Ca(2+)/calmodulin-dependent protein kinase (CaMK) family, whose physiological roles in regulating meiotic cell cycle needs to be determined. We showed by Western blot that CaMKK was expressed in pig oocytes at various maturation stages. Confocal microscopy was employed to observe CaMKK distribution. In oocytes at the germinal vesicle (GV) or prometaphase I (pro-MI) stage, CaMKK was distributed in the nucleus, around the condensed chromatin and the cortex of the cell. At metaphase I (MI) stage, CaMKK was concentrated in the cortex of the cell. After transition to anaphase I or telophase I stage, CaMKK was detected around the separating chromosomes and in the cortex of the cell. At metaphase II (MII) stage, CaMKK was localized to the cortex of the cell, with a thicker area near the first polar body (PB1). Treatment of pig cumulus-enclosed oocytes with STO-609, a membrane-permeable CaMKK inhibitor, resulted in the delay/inhibition of the meiotic resumption and the inhibition of first polar body emission. The correlation between CaMKK and microfilaments during meiotic maturation of pig oocytes was then studied. CaMKK and microfilaments were colocalized from MI to MII during porcine oocyte maturation. After oocytes were treated with STO-609, microfilaments were depolymerized, while in oocytes exposed to cytochalasin B (CB), a microfilament polymerization inhibitor, CaMKK became diffused evenly throughout the cell. These data suggest that CaMKK is involved in regulating the meiotic cell cycle probably by interacting with microfilaments in pig oocytes.
Xu
Bao-Zeng
BZ
State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Datun Road, Chaoyang, Beijing 100101, China.
Li
Mo
M
Xiong
Bo
B
Lin
Sheng-Li
SL
Zhu
Jia-Qiao
JQ
Hou
Yi
Y
Chen
Da-Yuan
DY
Sun
Qing-Yuan
QY
D008841:Actin Cytoskeleton / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D000818:Animals; D001562:Benzimidazoles / Q000494:pharmacology; D015153:Blotting, Western / Q000662:veterinary; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D003571:Cytochalasin B / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D008540:Meiosis / Q000187:drug effects / Q000502:physiology*; D018613:Microscopy, Confocal / Q000662:veterinary; D008856:Microscopy, Fluorescence / Q000662:veterinary; D053644:Naphthalimides / Q000494:pharmacology; D009865:Oocytes / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology*; D013552:Swine / Q000502:physiology*
D001562:Benzimidazoles; D004791:Enzyme Inhibitors; D053644:Naphthalimides; C458525:STO 609; D003571:Cytochalasin B; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase