Binding and cooperative interactions between two B cell-specific transcriptional coactivators.
The class II transactivator (CIITA) and B cell octamer-binding protein 1/octamer-binding factor 1/Oct coactivator from B cells (Bob1/OBF-1/OCA-B) represent two B cell-specific transcriptional coactivators. CIITA and Bob1 interact with proteins that bind to conserved upstream sequences in promoters of class II major histocompatibility genes and octamer-binding transcription factors Oct-1 and Oct-2, respectively. Both CIITA and Bob1 increase the expression from the DRA promoter, which is a prototypic class II promoter. Moreover, in the presence of CIITA, interactions between class II promoters and Bob1 are independent of the octamer-binding site. Using in vivo and in vitro binding assays, we confirm that Bob1 binds to CIITA. Thus, CIITA not only activates the expression of class II genes but recruits another B cell-specific coactivator to increase transcriptional activity of class II promoters in B cells.
Fontes
J D
JD
Howard Hughes Medical Institute, Departments of Medicine, University of California, at San Francisco 94143-0724, USA.
Jabrane-Ferrat
N
N
Toth
C R
CR
Peterlin
B M
BM
D001402:B-Lymphocytes / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis; D017124:Conserved Sequence; D005802:Genes, MHC Class II; D006801:Humans; D010957:Plasmids; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000096:biosynthesis; D016385:TATA Box; D015534:Trans-Activators / Q000378:metabolism*; D015533:Transcriptional Activation; D014162:Transfection
C091546:POU2AF1 protein, human; D011994:Recombinant Proteins; D015534:Trans-Activators; D015500:Chloramphenicol O-Acetyltransferase