Growth hormone induces insulin-like growth factor-I gene transcription by a synergistic action of STAT5 and HNF-1alpha.
Salmon insulin-like growth factor-I (sIGF-I) expression is, as in mammals, induced by growth hormone (GH). To elucidate the mechanism by which GH stimulates the transcription of the IGF-I gene, we transiently transfected Hep3B cells expressing the rat GH receptor with a sIGF-I promoter-luciferase reporter construct. Activation of the construct by GH added to the medium of the transfected cells was observed when two specific transcription factors, STAT5 and HNF-1alpha, were simultaneously overexpressed in these cells. This finding demonstrates for the first time a GH-dependent activation of an IGF-I promoter construct in an immortalized laboratory cell line.
Laboratory for Physiological Chemistry, Utrecht University, The Netherlands.
I
I
Metón
E P
EP
Boot
J S
JS
Sussenbach
P H
PH
Steenbergh
D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics*; D005786:Gene Expression Regulation / Q000235:genetics*; D017930:Genes, Reporter / Q000235:genetics; D013006:Growth Hormone / Q000494:pharmacology*; D051537:Hepatocyte Nuclear Factor 1; D051538:Hepatocyte Nuclear Factor 1-alpha; D051539:Hepatocyte Nuclear Factor 1-beta; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D008894:Milk Proteins; D009687:Nuclear Proteins; D011401:Promoter Regions, Genetic / Q000235:genetics; D011986:Receptors, Somatotropin / Q000235:genetics; D050799:STAT5 Transcription Factor; D012474:Salmon / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*; D015533:Transcriptional Activation / Q000235:genetics; D014162:Transfection / Q000235:genetics; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; D051538:Hepatocyte Nuclear Factor 1-alpha; D008894:Milk Proteins; D009687:Nuclear Proteins; D011986:Receptors, Somatotropin; D050799:STAT5 Transcription Factor; D015534:Trans-Activators; D014157:Transcription Factors; D051537:Hepatocyte Nuclear Factor 1; D051539:Hepatocyte Nuclear Factor 1-beta; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone