Molecular cloning of a teleost growth hormone receptor and its functional interaction with human growth hormone

This paper reports the first full-length cDNA sequence of a growth hormone receptor (GHR) from a teleost fish and its functional expression in culture d eukaryotic cells. The cDNA sequence, from Carassius auratus (goldfish), e ncodes a protein of 602 amino acids (aa) akin in architecture to the GHRs o f other species. Despite the presence of motifs characteristic of GHR, the overall homology between the goldfish GHR and other GHRs is very low (appro ximate to 40% aa identity). CHO cells transfected with this receptor cDNA c an be stimulated to proliferate by human growth hormone hGH). In addition, the transfected cells can transactivate a co-expressed mammalian serine pro tease inhibitor (Spi) 2.1 promoter upon stimulation by hGH. indicating the successful interaction of the fish receptor with the mammalian ligand to ev oke the down-stream post-receptor events. Tissue distribution studies indic ated that the receptor is mostly expressed in the liver and hypothalamus of goldfish. A single mRNA transcript of a size of about 4 kb was found in th e goldfish liver. (C) 2001 Elsevier Science B.V. All rights reserved.