Nuclear factor-I and activator protein-2 bind in a mutually exclusive way to overlapping promoter sequences and trans-activate the human growth hormone gene.
Transcription of the human growth hormone (hGH) gene and its regulation are controlled by trans-acting factors that bind to hGH gene promoter sequences. Several DNase I footprints have been described within 500 bp of this promoter, one of which (-289 to -267) has not yet been ascribed to a defined factor. By DNase I footprinting, gel mobility shift, and methylation interference assays with extracts from HeLa cells and GH-producing pituitary tumor (GC) cells, we show that this factor belongs to the NF-I family. When NF-I was competed out of the cell extracts, the trans-acting factor AP-2 bound to the same site as NF-I. AP-2 was present not only in HeLa cells, but also in GC cells albeit at a much lower concentration. Consistent with the mutually exclusive binding of NF-I and AP-2, their methylation interference patterns included four guanine residues that were crucial for binding of both NF-I and AP-2. Cell-free transcription from the hGH gene promoter showed that these two factors can transactivate this gene.
Courtois
S J
SJ
Hormone and Metabolic Research Unit, Louvain University Medical School, Brussels, Belgium.
Lafontaine
D A
DA
Lemaigre
F P
FP
Durviaux
S M
SM
Rousseau
G G
GG
D001483:Base Sequence; D001667:Binding, Competitive; D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation; D013006:Growth Hormone / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides / Q000378:metabolism; D011485:Protein Binding; D050656:Transcription Factor AP-2; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D051840:Y-Box-Binding Protein 1
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides; D050656:Transcription Factor AP-2; D014157:Transcription Factors; D051840:Y-Box-Binding Protein 1; C070856:YBX1 protein, human; D013006:Growth Hormone