Activating transcription factor 2 targets c-Fos, but not c-Jun, in growth plate chondrocytes

✍ Scribed by Xinying Li; Phyllis LuValle

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 298 KB
• Volume: 112
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/jcb.22925

✦ Synopsis

Abstract

Activating transcription factor 2 (ATF‐2), c‐Fos, and c‐Jun belong to the bZIP family of transcription factors. Promoters of c‐Fos, c‐Jun, cyclin D1, and cyclin A are targets of ATF‐2 in primary mouse chondrocytes. An ATF‐2 expression vector was co‐transfected with either c‐Fos or c‐Jun promoters in mutant ATF‐2 chondrocytes in order to show by luciferase assay that ATF‐2 increased promoter activity of c‐Fos, but not c‐Jun. Chromatin immunoprecipitation (ChIP) assays revealed that ATF‐2 bound with the c‐Fos promoter at the −294 cyclic AMP response element (CRE) site, but did not bind to the TPA responsive element (TRE) or activating protein‐1 (AP1) sites of the c‐Jun promoter. Dominant‐negative (dn) c‐Fos inhibited cyclin D1 promoter activity. However, dn c‐Jun had minimal effect on this same promoter activity. c‐Fos was capable of interactions with both the cyclin D1 CRE and AP1 sites, while c‐Jun co‐operated specifically with the cyclin D1 CRE site. Neither c‐Fos nor c‐Jun had any effect on cyclin A promoter activity. c‐Fos was unable to bind to the cyclin A AP1 or CRE sites. In contrast c‐Jun was competent in interactions with cyclin A AP1‐2 as well as the CRE. J. Cell. Biochem. 112: 211–216, 2011. © 2010 Wiley‐Liss, Inc.