Identification of a growth hormone-responsive STAT5-binding element in the rat insulin 1 gene.
GH and PRL stimulate both proliferation and insulin production in pancreatic beta-cells as well as in the rat insulinoma cell line RIN-5AH, We report here that human GH increases insulin mRNA levels in RIN-5AH cells via both somatogenic and lactogenic receptors. GH stimulated the rat insulin 1 promoter activity 2-fold, and this stimulation was abolished by introduction of a block mutation in a gamma-interferon-activated sequence (GAS)-like element (GLE) with the sequence 5'-TTCTGGGAA-3' located in the rat insulin 1 enhancer at position -330 to -322. This element, termed Ins-GLE, was able to confer GH responsiveness to a heterologous promoter. GH induced the binding of two protein complexes to the Ins-GLE. An antibody directed against the transcription factor STAT5 (signal transducer and activator of transcription) supershifted the GH-induced complexes. Furthermore, in COS7 cells transiently transfected with STAT5 and GH receptor cDNAs, it was found that expression of STAT5 was necessary for GH induction of these two DNA-binding complexes. These results suggest that GH stimulates insulin 1 promoter activity by inducing the binding of STAT5 to Ins-GLE.
Galsgaard
E D
ED
Hagedom Research Institute, Gentofte, Denmark.
Gouilleux
F
F
Groner
B
B
Serup
P
P
Nielsen
J H
JH
Billestrup
N
N
D000818:Animals; D001665:Binding Sites; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D013006:Growth Hormone / Q000378:metabolism / Q000494:pharmacology*; D007328:Insulin / Q000235:genetics* / Q000378:metabolism*; D007340:Insulinoma / Q000188:drug therapy / Q000473:pathology; D008894:Milk Proteins; D011401:Promoter Regions, Genetic; D011506:Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis / Q000187:drug effects; D051381:Rats; D050799:STAT5 Transcription Factor; D015534:Trans-Activators / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D015854:Up-Regulation
D004268:DNA-Binding Proteins; D007328:Insulin; D008894:Milk Proteins; D011506:Proteins; D012333:RNA, Messenger; D050799:STAT5 Transcription Factor; D015534:Trans-Activators; D013006:Growth Hormone