Nuclear factor 1 is essential for the expression of stearoyl-CoA desaturase 1 gene during preadipocyte differentiation.

Stearoyl CoA desaturase gene 1 (SCD1) is a delta 9 desaturase that is transcriptionally activated during the differentiation of 3T3-L1 preadipocytes into adipocytes. We have demonstrated that a SCD1/BP region in SCD1 proximal promoter (-114 to -86 bp) is essential for the transcriptional activation of this gene during differentiation. Mutation in this region abolished the basal activity of the proximal promoter of SCD1, and also failed to induce transcription in response to the differentiation cocktail in transfected cells. The SCD1/BP region contains a TGGCA sequence at -90 bp from the transcription start site. Using competitor oligonucleotides and nuclear factor 1 (NF1)-specific antibodies in gel shift assays, we have shown that in preadipocytes, a NF1 protein binds to this TGGCA sequence. On MDI-induced differentiation of preadipocyte into adipocyte, an additional DNA-protein complex appeared. The appearance of a new NF1 complex is related to the differentiation-specific transcriptional activation of the SCD1 gene. This is the first report to show a differentiation-related change in NF1 protein binding during preadipocyte differentiation.