Activated α subunit of G(o) protein induces oocyte maturation

S. D. Kroll, G. Omri, E. M. Landau, R. Iyengar

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28 Scopus citations


The capability of various activated guanine nucleotide binding regulatory protein (G protein) α subunits to induce meiotic maturation was studied. Activated G(o) protein α subunit (α*/(o)) but not the three inhibitory G protein α subunits triggered meiotic maturation in Xenopus oocytes. The effect was concentration dependent with a half-maximal effect in the 100-200 pM range. Injection of α*/(o) stimulated protein kinase C activity. Coinjection of the peptide containing residues 19-36 of protein kinase C [PKC-(19-36)], a specific protein kinase C inhibitor, blocked the α*/(o)- but not progesterone-induced maturation. Cycloheximide and the injection of antisense oligonucleotides specific to the c-mos transcript blocked α(o)-induced maturation. Immunoprecipitation with a mos protein-specific monoclonal antibody showed that α(o)-injected oocytes had phosphorylated mos protein. When PKC-(19-36) was coinjected with α*/(o), phosphorylated mos protein was not observed. These observations indicate that α*/(o), through protein kinase C and the translation of c-mos, can trigger meiotic division of Xenopus oocytes. Our results raise the possibility that persistently activated G proteins through cellular protooncogenes may regulate cell-cycle resumption.

Original languageEnglish
Pages (from-to)5182-5186
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number12
StatePublished - 1991
Externally publishedYes


  • Xenopus laevis
  • c-mos translation
  • protein kinase C


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