Expression of the rat growth-hormone gene is under the influence of a cell-type-specific silencer element.
We have previously shown that a cell-type-specific negative-regulatory element, or silencer, acts to specifically restrict rat-growth-hormone(rGH)-promoter activity to pituitary cells. Here we report a detailed characterization of this element. The activity of the silencer is dependent on its position relative to the promoter. The negative regulatory effect can be diminished by cotransfection with a high-copy-number, silencer-containing competitor plasmid, suggesting that the function of the element is mediated by specific binding of a trans-acting negative-regulatory factor. The minimal region required for silencer function is contained between positions -309 and -266 relative to the start of the rGH mRNA. The specific interaction of a nuclear protein from non-pituitary cells with this rGH DNA segment was shown by DNaseI as well as dimethylsulfate methylation-interference footprinting. A detailed examination of the DNA-binding site for that protein clearly suggest that it belongs to the NF1 family of transcription factors.
Guérin
S L
SL
Laboratory of Molecular Endocrinology, CHUL Research Center, Québec, Canada.
Anzivino
M J
MJ
Roy
R J
RJ
Moore
D D
DD
D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D013006:Growth Hormone / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D011485:Protein Binding; D051381:Rats; D011994:Recombinant Proteins / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid
D009687:Nuclear Proteins; D011994:Recombinant Proteins; D013006:Growth Hormone; D004247:DNA