TY - JOUR
AU - Rotwein,, P
AB - Abstract Insulin-like growth factor-I (IGF-I) is a highly conserved 70-residue circulating peptide that mediates many of the systemic growth-promoting effects of GH. This laboratory has found previously that GH rapidly stimulates hepatic IGF-I transcription in hypophysectomized (hypox) rats by activating promoter 1, the major rat IGF-I gene promoter. In this study, the hormonal regulation of IGF-I expression through promoter 2, a minor promoter in most tissues but active in the liver, was investigated. Through use of a sensitive RNase protection assay, GH was shown to rapidly induce the accumulation of correctly initiated transcripts directed by this promoter in hepatic nuclei. Using in vitro DNase-I footprinting, six DNA-protein interactions were identified within promoter 2 with hepatic nuclear extracts from juvenile male hypox rats given a single ip injection of GH or saline 60 min before death. These DNA-protein-binding complexes also were investigated for specificity and for regulation by GH by gel mobility shift assays. All DNA-protein interactions were detected in hepatic nuclear protein extracts from hypox rats and did not change within 15-120 min after GH treatment. These results thus identify and characterize a series of constitutive nuclear protein-binding sites within the second rat IGF-I promoter that may be involved in mediating its transcriptional activity. This content is only available as a PDF. Copyright © 1995 by The Endocrine Society
TI - Rapid activation of rat insulin-like growth factor-I gene transcription by growth hormone reveals no changes in deoxyribonucleic acid-protein interactions within the second promoter
JO - Endocrinology
DO - 10.1210/endo.136.5.7720672
DA - 1995-05-01
UR - https://www.deepdyve.com/lp/oxford-university-press/rapid-activation-of-rat-insulin-like-growth-factor-i-gene-IMpnuCdJvI
SP - 2230
EP - 2237
VL - 136
IS - 5
DP - DeepDyve
ER -