Regulation of maternal gene expression by MEK/MAPK and MPF signaling in porcine oocytes during in vitro meiotic maturation.
Mitogen-activated protein kinase (MAPK) and maturation/M phase promoting factor (MPF) play crucial roles in oocyte meiotic maturation in mammals. However, the underlying molecular mechanisms have not been addressed. In this study, the effects of the MEK/MAPK pathway inhibitor U0126 and the MPF inhibitor roscovitine on meiotic maturation and maternal gene expression in pig cumulus-oocyte complexes (COCs) and denuded oocytes (DOs) were investigated. Both inhibitors can reversibly block the resumption of meiosis in pig oocytes. COCs or DOs initially cultured in drug-free medium for 24 h and then transferred to medium containing U0126 showed normal progress to the Metaphase II stage (MII); (90.38 vs. 92.16% control group). In contrast, roscovitine treatment from 24 to 44 h significantly inhibited maturation of COCs and DOs. To explore the underlying molecular mechanisms, expression patterns and polyadenylation states of five representative maternal transcripts, cyclin B1, Cdc2, C-mos, GDF9 and BMP15, were examined by real-time PCR and poly(A)-test PCR (PAT assay). U0126 treatment resulted in aberrant expression of Cdc2 and GDF9, while roscovitine significantly maintained all five maternal transcripts at very high levels in treated COCs compared with the control group. The polyadenylation of these mRNAs increased as well. Furthermore, the experiments were repeated in DOs, and the results also indicated that both Cdc2 and GDF9 showed significantly higher expression in both mRNA and polyadenylation levels in the drug treatment groups. Together, these results provide the first demonstration in a mammalian system that MAPK and MPF play important roles in regulation of maternal gene expression during oocyte maturation.
Zhang
Ding-Xiao
DX
Department of Animal Sciences, Chungbuk National University, Cheongju, Korea.
Park
Won-Jun
WJ
Sun
Shao-Chen
SC
Xu
Yong-Nan
YN
Li
Ying-Hua
YH
Cui
Xiang-Shun
XS
Kim
Nam-Hyung
NH
D000818:Animals; D055430:Bone Morphogenetic Protein 15 / Q000235:genetics / Q000378:metabolism; D002070:Butadienes / Q000494:pharmacology; D016203:CDC2 Protein Kinase / Q000235:genetics / Q000378:metabolism; D054885:Cumulus Cells / Q000502:physiology; D056744:Cyclin B1 / Q000235:genetics / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D055429:Growth Differentiation Factor 9 / Q000235:genetics / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D016200:Maturation-Promoting Factor / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008938:Mitosis / Q000187:drug effects; D050258:Mitosis Modulators / Q000494:pharmacology; D009570:Nitriles / Q000494:pharmacology; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism*; D009866:Oogenesis / Q000187:drug effects; D026723:Polyadenylation / Q000187:drug effects; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D017231:Proto-Oncogene Proteins c-mos / Q000235:genetics / Q000378:metabolism; D011687:Purines / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D000077546:Roscovitine; D034421:Sus scrofa
D055430:Bone Morphogenetic Protein 15; D002070:Butadienes; D056744:Cyclin B1; D055429:Growth Differentiation Factor 9; D050258:Mitosis Modulators; D009570:Nitriles; D047428:Protein Kinase Inhibitors; D011687:Purines; D012333:RNA, Messenger; C113580:U 0126; D000077546:Roscovitine; D017231:Proto-Oncogene Proteins c-mos; D016203:CDC2 Protein Kinase; D016200:Maturation-Promoting Factor