A Major Substrate for MPF: cDNA Cloning and Expression of Polypeptide Chain Elongation Factor 1γ from Goldfish ( Carassius auratus )

One of the eukaryotic polypeptide chain elongation factors, EF-1 g n i complex, is involved in polypeptide chain elongation via the GDP/GTP exchange activity of EF-1 f. In the complex, EF-1 n has been reported to be a major substrate for maturation promoting factor (MPF). Here, we present the cloning, sequencing and expression analysis of goldfish, Carassius auratus, EF-1 n from the goldfish ovary. The cloned cDNA was 1490 u bp in length and encoded 442 amino acids. The deduced amino acid sequence was highly homologous to EF-1 n from other species. Although, the phosphorylation site identified in Xenopus EF-1 n was not conserved in the goldfish homologue, phosphorylation analysis showed that the goldfish EF-1 n was phosphorylated by MPF. We concluded that EF-1 n is a substrate for MPF during oocyte maturation in goldfish.