The chum salmon IGF-II gene promoter is activated by hepatocyte nuclear factor 3 beta

IGF-II plays an important role in growth and development of vertebrates and is highly expressed in adult salmon liver. In the present study, me demons trate that a liver-enriched transcription factor, hepatocyte nuclear factor 3 beta (HNF-3 beta), is an activator of the chum salmon IGF-II gene. Multi ple binding sites for HNF3 beta were identified within the 5'-UTR using ele ctrophoretic mobility shift assays and mutation of these sites prevents bin ding of HNF-3 beta. In transient transfection assays it mas shown that muta tion of the HNF-3 beta binding sites results in a substantial decrease of H NF3 beta-activated salmon IGF-II gene expression, This is the first identif ied transcription factor that is functionally involved in the regulation of fish IGF-II expression, (C) 1999 Federation of European Biochemical Societ ies.