Identification of a transcription factor that binds to the S box of the I-A beta gene of the major histocompatibility complex.
Class II genes of the MHC show a striking homology upstream of the transcription start site that is composed of three conserved sequences (S, X and Y boxes, each separated by 15-20 bp). The presence of the S-box sequence in the mouse MHC class II gene I-A Beta was examined for its influence on the expression of this gene. Deletion or mutation of the S box decreased the induction of chloramphenicol acetyltransferase (CAT) activity in B lymphocytes by 32%. In macrophages, deletion or mutation of the S box abolished interferon-gamma (IFN-gamma) inducibility of CAT activity. Using a gel-retardation assay, we have identified a nuclear factor whose binding site overlaps the 7-mer conserved sequence of the S box. This factor is present in lymphocytes, macrophages, mastocytes and fibroblasts. Surprisingly, binding of this nuclear factor to DNA was induced by IFN-gamma in bone-marrow-derived macrophages, but not in macrophage-like cell lines. The binding site for this factor was defined by DNase I footprinting and partially purified by using an affinity column containing double-stranded oligonucleotides containing a sequence of the S box. A prominent protein of 43 kDa was found that bound specifically to the S-box sequence.
Celada
A
A
Department de Fisiologia (Immunologia), Facultad de Biologia, Universtat de Barcelona, Spain.
Gil
P
P
McKercher
S R
SR
Maki
R A
RA
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis / Q000235:genetics; D017124:Conserved Sequence; D004247:DNA / Q000235:genetics* / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D015870:Gene Expression; D005802:Genes, MHC Class II; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016296:Mutagenesis; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D014162:Transfection
D014157:Transcription Factors; D004247:DNA; D015500:Chloramphenicol O-Acetyltransferase