CREB and phospho-CREB interact with RFX5 and CIITA to regulate MHC class II genes.
Major histocompatibility class II (MHC-II) genes are coordinately regulated by conserved, upstream promoter elements that are bound cooperatively by cyclic AMP response element binding protein (CREB), regulatory factor X (RFX), and nuclear factor Y (NF-Y). These DNA-binding proteins serve as a scaffold for the transcriptional coactivator class II transactivator (CIITA). To determine how CREB interacts with RFX and CIITA, co-immunoprecipitations and reporter assays were performed using a variety of CREB mutants. These assays demonstrated that CREB interacted with CIITA and the RFX5 subunit of RFX through the C-terminal portion of CREB. This C-terminal portion of CREB was fully functional in MHC-II promoter reporter assays. Phosphorylation of CREB enhanced transcription from the reporter, but was not required for transcription. Phospho-CREB was found at the HLA-DRA promoter by chromatin immunoprecipitation, providing evidence for its role. Together, these data provide genetic and biochemical evidence of the specific associations between CREB and two elements of the MHC-II regulatory complex and of the role played by phosphorylated CREB at MHC-II promoters.
Lochamy
Jonathan
J
Department of Microbiology and Immunology, Emory University School of Medicine, 1510 Clifton Rd., Atlanta, GA 30322, USA.
Rogers
Edward M
EM
Boss
Jeremy M
JM
D000818:Animals; D019556:COS Cells; D050882:CREB-Binding Protein / Q000378:metabolism*; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D017362:Cyclic AMP Response Element-Binding Protein / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005802:Genes, MHC Class II / Q000235:genetics*; D051379:Mice; D009154:Mutation; D009687:Nuclear Proteins / Q000378:metabolism*; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins; D000071701:Regulatory Factor X Transcription Factors; D012694:Serine / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection
D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; C083728:MHC class II transactivator protein; D009687:Nuclear Proteins; D011994:Recombinant Proteins; D000071701:Regulatory Factor X Transcription Factors; D015534:Trans-Activators; D014157:Transcription Factors; D012694:Serine; D050882:CREB-Binding Protein