Hypoxia and DNA-damaging agent bleomycin both increase the cellular level of the protein 4E-BP.
The 4E-binding proteins (4E-BPs) regulate the cap-dependent eukaryotic initiation factor 4E (eIF4E). The level of 4E-BP protein is regulated during early development of sea urchin embryos. Fertilization leads to the rapid disappearance of the protein that reappears later in development. We show that two important cellular stresses, hypoxia and bleomycin prolonged checkpoint mobilization provoked the overexpression of the protein 4E-BP in developing sea urchin embryos. Hypoxia resulted after 1 h in a reversible gradual increase in the protein 4E-BP level. At 20 h, the protein 4E-BP had reached the level existing in the unfertilized eggs. Bleomycin used as a DNA-damaging agent for checkpoint activation, provoked cell cycle inhibition and after prolonged exposure (20 h), induced the expression of the protein 4E-BP. The effect of bleomycin on 4E-BP protein overexpression was dose-dependent between 0.4 and 1.2 mM. The role of the overexpression of the protein 4E-BP is discussed in relation with cellular stress responses.
Le Bouffant
Ronan
R
Equipe Cycle Cellulaire et Développement, Unité de Recherche Mer & Santé, UMR 7150, Centre National de la Recherche Scientifique (CNRS) and Université Pierre et Marie Curie (UPMC), Station Biologique de Roscoff 29682 Roscoff Cedex France.
Cormier
Patrick
P
Mulner-Lorillon
Odile
O
Bellé
Robert
R
D000818:Animals; D001761:Bleomycin / Q000494:pharmacology*; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology; D004249:DNA Damage / Q000502:physiology*; D004625:Embryo, Nonmammalian / Q000187:drug effects / Q000378:metabolism; D047108:Embryonic Development / Q000187:drug effects; D005260:Female; D000860:Hypoxia / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D010063:Ovum / Q000187:drug effects / Q000378:metabolism; D010448:Peptide Initiation Factors / Q000378:metabolism*; D012617:Sea Urchins / Q000196:embryology
D047908:Intracellular Signaling Peptides and Proteins; D010448:Peptide Initiation Factors; D001761:Bleomycin