Mutational analysis of the DRA promoter: cis-acting sequences and trans-acting factors.
Class II major histocompatibility genes are expressed at high levels in B lymphocytes and are gamma interferon (IFN-gamma) inducible in many other cells. Previously, we observed that DRA promoter sequences from positions -150 to +31 determine the tissue specificity of this class II gene. Moreover, Z and X boxes located between positions -145 and -87 conferred B-cell specificity and IFN-gamma inducibility upon a heterologous promoter. In this study, sequences from positions -145 to -35 in the DRA promoter were systematically mutated by using oligonucleotide cassettes. Z (-131 to -125), pyrimidine (-116 to -109), X (-108 to -95), Y (-73 to -61), and octamer (-52 to -45) boxes were required for B-cell specificity and, with the exception of the octamer box, for IFN-gamma inducibility. Z box and sequences flanking Z and X boxes helped to determine low levels of expression in T and uninduced cells. In phenotypically distinct cells, shared and distinct proteins bound to these conserved upstream sequences. However, few correlations between expression and DNA-binding proteins could be made. Similar proteins bound to Z and X boxes, and the Z box most likely represents a duplication of the X box.
Tsang
S Y
SY
Department of Medicine, Howard Hughes Medical Institute, University of California, San Francisco 94143-0724.
Nakanishi
M
M
Peterlin
B M
BM
D001483:Base Sequence; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D005802:Genes, MHC Class II / Q000187:drug effects; D006684:HLA-DR Antigens / Q000235:genetics*; D006367:HeLa Cells / Q000276:immunology; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D015345:Oligonucleotide Probes; D010957:Plasmids; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins; D015534:Trans-Activators / Q000378:metabolism*; D014162:Transfection
D006684:HLA-DR Antigens; D015345:Oligonucleotide Probes; D011994:Recombinant Proteins; D015534:Trans-Activators; D007371:Interferon-gamma