A fibroblast-specific factor binds to an upstream negative control element in the promoter of the mouse alpha 1(I)...

We have identified, in nuclear extracts of NIH-3T3 fibroblasts, a factor which binds a sequence between -339 and -361 in the mouse alpha 1(I) collagen promoter. A 3-base pair substitution mutation introduced in this promoter element, which abolishes the binding of the factor, increases the activity of the promoter 4-fold in DNA transfection experiments. This suggests that this element is a negative regulator of transcription. The factor which binds to the -339 to -361 sequence is present in type I collagen-producing cell lines but not in a variety of other cell types, suggesting that it is involved in the tissue-specific regulation of the alpha 1(I) gene.