Fig. 1.

Schematic representation of the human c-fos promoter illustrating the in-context mutations. All c-fos gene constructs contain 711 bp of c-fos upstream regulatory sequence and the entire transcribed region. The start of transcription is indicated by anarrow. The base changes used to create the promoter mutants are shown in bold below the wild-type sequence. The ΔCRE and ΔSIF mutations both generate Gal4 binding sites and abrogate the binding of CREB/ATF and sis-inducible factor (SIF)/STAT, respectively. TheΔTCF mutation generates a LexA half-site and blocks ternary complex formation; the ΔSRF mutation creates an MCM1 site that cannot bind SRF. The consensus binding sites for STAT factors, TCFs, SRF, and CREB/ATF are indicated byasterisks.