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MAPK inactivation is required for the G 2 to M‐phase transition of the first mitotic cell cycle
Author(s) -
Abrieu Ariane,
Fisher Daniel,
Simon MarieNoélle,
Dorée Marcel,
Picard André
Publication year - 1997
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/16.21.6407
Subject(s) - biology , mitosis , microbiology and biotechnology , mapk/erk pathway , metaphase , human fertilization , cyclin dependent kinase 1 , maturation promoting factor , cell cycle , mapk cascade , kinase , cell , genetics , chromosome , gene
Down‐regulation of MAP kinase (MAPK) is a universal consequence of fertilization in the animal kingdom, although its role is not known. Here we show that MAPK inactivation is essential for embryos, both vertebrate and invertebrate, to enter first mitosis. Suppressing down‐regulation of MAPK at fertilization, for example by constitutively activating the upstream MAPK cascade, specifically suppresses cyclin B‐cdc2 kinase activation and its consequence, entry into first mitosis. It thus appears that MAPK functions in meiotic maturation by preventing unfertilized eggs from proceeding into parthenogenetic development. The most general effect of artificially maintaining MAPK activity after fertilization is prevention of the G 2 to M‐phase transition in the first mitotic cell cycle, even though inappropriate reactivation of MAPK after fertilization may lead to metaphase arrest in vertebrates. Advancing the time of MAPK inactivation in fertilized eggs does not, however, speed up their entry into first mitosis. Thus, sustained activity of MAPK during part of the first mitotic cell cycle is not responsible for late entry of fertilized eggs into first mitosis.