A CONSERVED REGION IN THE FIRST INTRON OF THE INSULIN-RECEPTOR GENE BINDS NUCLEAR PROTEINS DURING ADIPOCYTE DIFFERENTIATION

The insulin receptor gene is induced 8 to 10-fold during adipocyte dif ferentiation. Plasmids containing the promoter, exon 1 and a portion o f the first intron from either the mouse or human gene are able to mod ulate the expression of an insulin receptor/CAT gene 3 to 7-fold durin g differentiation. We have shown that several nuclear proteins from bo th preadipocyte and adipocyte nuclear extracts bind to two discrete si tes within a 278-bp region in the 5' end of the first intron. Sequence comparison between the first intron of the human gene and the mouse g ene shows two regions of sequence identity which correspond to the pro tein binding regions detected by DNase footprinting. One of these site s binds proteins that are enriched in adipocyte nuclear extracts and c an be competed by adipose regulatory element, ARE6. (C) 1997 Academic Press.