Cellular apoptosis susceptibility gene messenger ribonucleic acid in the ovary of red seabream: molecular cloning and correlation with acquisition ofoocyte maturational competence

This study has used differential display-PCR, to amplify genes transcribed during oocyte maturation induced by human chorionic gonadotropin (hCG). A c DNA expressed in time of acquisition of oocyte maturation of red seabream ( Pagrus major) by treatment of hCG was amplified and cloned. A full-length c DNA of the cellular apoptosis susceptibility gene for red seabream was isol ated using differential display-PCR and 5' RACE. This cDNA clone contained 3560 nucleotides including the open reading frame (ORF) that encoded a prot ein of 971 amino acids. The deduced amino acid sequence shows 87% identity and 97% similarity to human cellular apoptosis susceptibility gene. Consens us sequences consistent with sites for phosphorylation by protein kinase C was identified. Red seabream cellular apoptosis susceptibility gene (CAS) t ranscript level increased between 9 and 12 h after the incubation with hCG. Red seabream CAS mRNA transcript level was increased by treatment of GtH-I I (300 ng ml(-1)). Moreover, in vivo, red seabream CAS mRNA was strongly ex pressed after, but not before the acquisition of oocyte maturational compet ence. These results suggest that an obligatory element of the hCG induction of maturational competence is the de novo synthesis of red seabream, Pagru s major CAS (PmCAS).