Identification of an upstream regulatory region essential for cell type-specific transcription of the pro-alpha 2(V) collagen gene (COL5A2).

The transcriptional features of the human alpha 2(V) collagen gene (COL5A2) were examined by transfection experiments coupled to various DNA binding assays. This approach identified an upstream region essential for the cell type-specific expression of the COL5A2 promoter. Within this region are two nuclear factor-binding sites, FP-A and FP-B, responsible for the formation of distinct DNA-protein complexes. Mutations introduced across each of the two binding sites eliminated the formation of the cognate complex and decreased promoter activity by about 3-fold (FP-A) and 40-fold (FP-B) in transfection experiments. Competition experiments using recognition sequences for known transcription factors exhibiting some similarity to the FP-A- and FP-B-binding sites failed to inhibit COL5A2/protein interactions. Thus, COL5A2 expression appears to be under the positive control of a short regulatory sequence likely to harbor two novel nuclear factor-binding sites.