Mos is not required for the initiation of meiotic maturation in Xenopus oocytes.
In Xenopus oocytes, the c-mos proto-oncogene product has been proposed to act downstream of progesterone to control the entry into meiosis I, the transition from meiosis I to meiosis II, which is characterized by the absence of S phase, and the metaphase II arrest seen prior to fertilization. Here, we report that inhibition of Mos synthesis by morpholino antisense oligonucleotides does not prevent the progesterone-induced initiation of Xenopus oocyte meiotic maturation, as previously thought. Mos-depleted oocytes complete meiosis I but fail to arrest at metaphase II, entering a series of embryonic-like cell cycles accompanied by oscillations of Cdc2 activity and DNA replication. We propose that the unique and conserved role of Mos is to prevent mitotic cell cycles of the female gamete until the fertilization in Xenopus, starfish and mouse oocytes.
Dupré
Aude
A
Laboratoire de Biologie du Développement, UMR-CNRS 7622, Université Pierre et Marie Curie, boîte 24, 4 place Jussieu, 75252 Paris cedex 05, France.
Jessus
Catherine
C
Ozon
René
R
Haccard
Olivier
O
D000818:Animals; D016203:CDC2 Protein Kinase / Q000378:metabolism; D019926:Cyclin B / Q000378:metabolism; D056765:Cyclin B2; D004261:DNA Replication; D004527:Egg Proteins / Q000235:genetics / Q000502:physiology*; D004789:Enzyme Activation; D005260:Female; D005816:Genetic Complementation Test; D020935:MAP Kinase Signaling System; D008540:Meiosis / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D009025:Morpholines / Q000494:pharmacology; D020319:Oligodeoxyribonucleotides, Antisense / Q000494:pharmacology; D009865:Oocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D009866:Oogenesis / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D014176:Protein Biosynthesis / Q000187:drug effects; D011494:Protein Kinases / Q000378:metabolism; D017231:Proto-Oncogene Proteins c-mos / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000502:physiology; D019893:Ribosomal Protein S6 Kinases; D013045:Species Specificity; D029867:Xenopus Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D014982:Xenopus laevis / Q000235:genetics / Q000502:physiology*
C503759:Ccnb2 protein, mouse; D019926:Cyclin B; D056765:Cyclin B2; D004527:Egg Proteins; D009025:Morpholines; D020319:Oligodeoxyribonucleotides, Antisense; D011993:Recombinant Fusion Proteins; D029867:Xenopus Proteins; D011494:Protein Kinases; D017231:Proto-Oncogene Proteins c-mos; D019893:Ribosomal Protein S6 Kinases; D016203:CDC2 Protein Kinase