Purified mu EBP-E binds to immunoglobulin enhancers and promoters.
We describe the purification to apparent homogeneity of the murine immunoglobulin heavy-chain (IgH) enhancer-binding protein mu EBP-E from murine plasmacytoma cells by ion exchange and affinity chromatography. Glycerol gradient sedimentation, UV cross-linking, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis confirm that mu EBP-E is a 45-kilodalton molecular mass protein. Orthophenanthroline-copper chemical nuclease footprinting with purified protein has identified high-affinity binding sites for mu EBP-E within the IgH enhancer at the previously identified site E and at sites within IgH promoters and in the kappa light-chain enhancer. Equilibrium binding studies indicate that the dissociation constants for mu EBP-E binding to site E within the enhancer and to a binding site within the V1 heavy-chain promoter are quite low, about 2 x 10(-11) M. Comparison of four mu EBP-E recognition sequences detects only limited sequence similarity among binding sites.
Peterson
C L
CL
Molecular Biology Institute, School of Medicine, University of California, Los Angeles 90024.
Eaton
S
S
Calame
K
K
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D051379:Mice; D008970:Molecular Weight; D016328:NF-kappa B; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000302:isolation & purification / Q000378:metabolism*
D004268:DNA-Binding Proteins; D007143:Immunoglobulin Heavy Chains; D016328:NF-kappa B; D014157:Transcription Factors; D004247:DNA