Open AccessCyclin B Translation Depends on mTOR Activity after Fertilization in Sea Urchin Embryos
Author(s) -
Héloïse Chassé,
Odile MulnerLorillon,
Sandrine Boulben,
Virginie Glippa,
Julia Morales,
Patrick Cormier
Publication year - 2016
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0150318
Subject(s) - cyclin b , microbiology and biotechnology , cyclin dependent kinase 1 , biology , cyclin d , cyclin b1 , cyclin a2 , cyclin a , polysome , eif4e , cell cycle , cyclin , protein kinase a , translation (biology) , kinase , messenger rna , biochemistry , cyclin dependent kinase 2 , rna , cell , ribosome , gene
The cyclin B/CDK1 complex is a key regulator of mitotic entry. Using PP242, a specific ATP-competitive inhibitor of mTOR kinase, we provide evidence that the mTOR signalling pathway controls cyclin B mRNA translation following fertilization in Sphaerechinus granularis and Paracentrotus lividus . We show that PP242 inhibits the degradation of the cap-dependent translation repressor 4E-BP (eukaryotic initiation factor 4E-Binding Protein). PP242 inhibits global protein synthesis, delays cyclin B accumulation, cyclin B/CDK1 complex activation and consequently entry into the mitotic phase of the cell cycle triggered by fertilization. PP242 inhibits cyclin B mRNA recruitment into active polysomes triggered by fertilization. An amount of cyclin B mRNA present in active polysomes appears to be insensitive to PP242 treatment. Taken together, our results suggest that, following sea urchin egg fertilization, cyclin B mRNA translation is controlled by two independent mechanisms: a PP242-sensitive and an additional PP242-insentitive mechanism.