Molecular cloning of cDNA encoding a cyclin‐selective ubiquitin carrier protein (E2‐C) from Carassius auratus (goldfish) and expression analysis of the cloned gene

Destruction of cyclin B is required for exit from mitosis and meiosis. A cyclin‐specific ubiquitinating system, including cyclin‐selective ubiquitin carrier protein (E2‐C), is thought to be responsible for cyclin B destruction. Here we present the cloning, sequencing and expression analysis of goldfish, Carassius auratus, E2‐C which encodes the cyclin‐selective ubiquitin carrier protein from goldfish ovary. The cloned cDNA is 677 bp long and encodes 172 amino acids. The deduced amino acid sequence is highly homologous to E2‐C from other species. Recombinant goldfish E2‐C possesses ubiquitinating activity against cyclin B. The expression of mRNA for E2‐C was similar to that of mRNA for cyclin B, occurring at very high level in the ovary. The similarity of the expression pattern of E2‐C and cyclin B suggests that E2‐C mediates a cyclin‐specific ubiquitination.