Isolation and Characterization of Two Distinct Growth Hormone cDNAs from the Goldfish,Carassius auratus

As a first step toward the development of a ribonuclease protection assay for studying the regulation of growth hormone (GH) gene expression in pituitary cells of the goldfish,Carassius auratus,we report the isolation of two cDNA clones encoding goldfish GH from a cDNA library prepared from pituitary poly(A)+RNA. The complete nucleotide sequences of these two GH cDNA clones have been determined and both of them were predicted to encode a polypeptide of 210 amino acids (aa) including a putative signal peptide of 22 aa. One of the GH cDNAs encodes a polypeptide (gfGHI) with five cysteine residues (similar to other carp GHs), whereas another encodes a polypeptide (gfGHII) with four cysteine residues (similar to most teleostean GHs). Because these two GH cDNAs have distinct nucleotide sequences at their coding and 3′ untranslated regions, they are likely to be encoded by two different genes.