Common factor 1 is a transcriptional activator which binds in the c-myc promoter, the skeletal alpha-actin promoter, and the immunoglobulin heavy-chain enhancer.

Ubiquitously expressed transcription factors play an integral role in establishing and regulating patterns of gene transcription. Common factor 1 (CF1) is a ubiquitously expressed DNA-binding protein previously identified in our laboratory. We show here that CF1 recognizes sites in several diverse transcription elements, and we demonstrate the ability of the c-myc CF1 site to activate transcription of a basal promoter in both B cells and fibroblasts.