Activating transcription factor 2 targets c-Fos, but not c-Jun, in growth plate chondrocytes.
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.
Department of Anatomy & Cell Biology, University of Florida, Gainesville, FL 32606-0235, USA.
Xinying
X
Li
Phyllis
P
LuValle
D051698:Activating Transcription Factor 2 / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D019902:Chondrocytes / Q000378:metabolism*; D047369:Chromatin Immunoprecipitation; D019938:Cyclin D1 / Q000235:genetics / Q000378:metabolism; D016758:Genes, jun / Q000235:genetics*; D006132:Growth Plate / Q000378:metabolism*; D051379:Mice; D011401:Promoter Regions, Genetic; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics*
D051698:Activating Transcription Factor 2; D016760:Proto-Oncogene Proteins c-fos; D019938:Cyclin D1