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

C. Le Stunff, M. J. Thomas, P. Rotwein

Research output: Contribution to journalArticle

18 Citations (Scopus)

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.

Original languageEnglish (US)
Pages (from-to)2230-2237
Number of pages8
JournalEndocrinology
Volume136
Issue number5
StatePublished - 1995
Externally publishedYes

Fingerprint

Insulin-Like Growth Factor I
Growth Hormone
Liver
DNA
Genes
Nuclear Proteins
Proteins
DNA Footprinting
Deoxyribonuclease I
DNA-Binding Proteins
Electrophoretic Mobility Shift Assay
Ribonucleases
Protein Binding
Gels
Binding Sites
Peptides
Injections
Growth
olifen
Therapeutics

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism

Cite this

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. / Le Stunff, C.; Thomas, M. J.; Rotwein, P.

In: Endocrinology, Vol. 136, No. 5, 1995, p. 2230-2237.

Research output: Contribution to journalArticle

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