Abstract
Interleukin-1 (IL-1)-induced mRNA expression of ccl2 (also called MCP-1), a prototypic highly regulated inflammatory gene, is severely suppressed in cells lacking c-Jun or Jun N-terminal protein kinase 1 (JNK1)/JNK2 genes and is only partially restored in cells expressing a c-Jun(SS63/73AA) mutant protein. We used chromatin immunoprecipitation to identify three c-Jun-binding sites located in the far 5' region close to the transcriptional start site and in the far 3' region of murine and human ccl2 genes. Mutational analysis revealed that the latter two sites contribute to ccl2 transcription in response to the presence of IL-1 or of ectopically expressed c-Jun-ATF-2 dimers. Further experiments comparing wild-type and c-Jun-deficient cells revealed that c-Jun regulates Ser10 phosphorylation of histone H3, acetylation of histones H3 and H4, and recruitment of histone deacetylase 3 (HDAC3), NF-kappaB subunits, and RNA polymerase II across the ccl2 locus. c-Jun also coimmunoprecipitated with p65 NF-kappaB and HDAC3. Based on DNA microarray analysis, c-Jun was required for full expression of 133 out of 162 IL-1-induced genes. For inflammatory genes, these data support the idea of an activator function of c-Jun that is executed by multiple mechanisms, including phosphorylation-dependent interaction with p65 NF-kappaB and HDAC3 at the level of chromatin.