The article reports the isolation and characterization of eight ATF (activating transcription factor) cDNA clones, each derived from a separate gene. These clones share a leucine zipper motif, which is also found in the AP-1/c-jun family of transcription factors. The ATF proteins bind to DNA as dimers and can form heterodimers that selectively bind to DNA. The study reveals that ATF represents an extensive family of related polypeptides, each with distinct functions, and that the diversity in their functions may be related to the different ways they interact with DNA. The findings provide insights into how a single promoter element, the ATF site, can be involved in the regulation of a wide variety of promoters.The article reports the isolation and characterization of eight ATF (activating transcription factor) cDNA clones, each derived from a separate gene. These clones share a leucine zipper motif, which is also found in the AP-1/c-jun family of transcription factors. The ATF proteins bind to DNA as dimers and can form heterodimers that selectively bind to DNA. The study reveals that ATF represents an extensive family of related polypeptides, each with distinct functions, and that the diversity in their functions may be related to the different ways they interact with DNA. The findings provide insights into how a single promoter element, the ATF site, can be involved in the regulation of a wide variety of promoters.