Cyclin synthesis controls the progression of meiotic maturation in mouse oocytes.
To study the mechanisms involved in the progression of meiotic maturation in the mouse, we used oocytes from two strains of mice, CBA/Kw and KE, which differ greatly in the rate at which they undergo meiotic maturation. CBA/Kw oocytes extrude the first polar body about 7 hours after breakdown of the germinal vesicle (GVBD), whilst the oocytes from KE mice take approximately 3-4 hours longer. In both strains, the kinetics of spindle formation are comparable. While the kinetics of MAP kinase activity are very similar in both strains (although slightly faster in CBA/Kw), the rise of cdc2 kinase activity is very rapid in CBA/Kw oocytes and slow and diphasic in KE oocytes. When protein synthesis is inhibited, the activity of the cdc2 kinase starts to rise but arrests shortly after GVBD with a slightly higher level in CBA/Kw oocytes, which may correspond to the presence of a larger pool of cyclin B1 in prophase CBA/Kw oocytes. After GVBD, the rate of cyclin B1 synthesis is higher in CBA/Kw than in KE oocytes, whilst the overall level of protein synthesis and the amount of messenger RNA coding for cyclin B1 are identical in oocytes from both strains. The injection of cyclin B1 messenger RNA in KE oocytes increased the H1 kinase activity and sped up first polar body extrusion. Finally, analysis of the rate of maturation in hybrids obtained after fusion of nuclear and cytoplasmic fragments of oocytes from both strains suggests that both the germinal vesicle and the cytoplasm contain factor(s) influencing the length of the first meiotic M phase. These results demonstrate that the rate of cyclin B1 synthesis controls the length of the first meiotic M phase and that a nuclear factor able to speed up cyclin B synthesis is present in CBA/Kw oocytes.
Polanski
Z
Z
Laboratoire de Biologie Cellulaire du Développement, Institut Jacques Monod, CNRS, Université Paris 6 and Université Paris 7, F-75005 Paris, France.
Ledan
E
E
Brunet
S
S
Louvet
S
S
Verlhac
M H
MH
Kubiak
J Z
JZ
Maro
B
B
D000818:Animals; D042846:CDC2-CDC28 Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002875:Chromosomes / Q000378:metabolism; D019926:Cyclin B / Q000235:genetics* / Q000378:metabolism; D056744:Cyclin B1; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases / Q000378:metabolism*; D005260:Female; D005455:Fluorescent Antibody Technique; D038362:Glycogen Synthase Kinase 3; D006822:Hybrid Cells / Q000378:metabolism; D007700:Kinetics; D008540:Meiosis / Q000502:physiology*; D051379:Mice; D008815:Mice, Inbred Strains; D008845:Microinjections; D008870:Microtubules / Q000378:metabolism; D008938:Mitosis / Q000235:genetics; D009865:Oocytes / Q000502:physiology*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics
C534700:Ccnb1 protein, mouse; D019926:Cyclin B; D056744:Cyclin B1; D012333:RNA, Messenger; D011494:Protein Kinases; C102333:histone H1 kinase; D017346:Protein Serine-Threonine Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D042846:CDC2-CDC28 Kinases; C495893:Cdk2 protein, mouse; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases; D038362:Glycogen Synthase Kinase 3