title: Ig S gamma-specific DNA binding protein SNAP is related to the helix-loop-helix transcription factor E47.
abstract: SNAP, a DNA-binding protein, is specific for the S gamma switch regions. Two E-2 box consensus binding motifs are located within the SNAP recognition site. Direct- and competition-binding analyses demonstrate that a truncated form of the E47 transcription factor, E47S, is capable of specific interactions with the SNAP binding motif. The methylation interference pattern for E47S binding on the pl.S gamma 3.A.1 probe was similar to that previously obtained for SNAP binding activity and was also related to that found for E47S on the microE5 probe. The interaction of purified E47S with the SNAP recognition motif was cooperative and formed complexes which migrated more slowly than the E47S homodimer complex. SNAP is distinguished from full-length E47 homodimers, found in BCF-1, by its migration position in the gel shift assay, differences in the competition-binding results and its unique reactivity with anti-E47 antibodies. SNAP is related to E47 as judged by a similar methylation interference pattern on S gamma 3 A site DNA and by its reactivity with anti-E47 mAb. The anti-E47 antibodies block SNAP binding to its cognate site, whereas anti-E47 antibodies supershift E47 homodimers bound to the microE5 recognition site. Thus, SNAP may be a hetero-oligomeric species containing E47 or highly related proteins.
authors.affiliation: Department of Microbiology and Immunology (M/C 790), University of Illinois College of Medicine, Chicago 60612-7344, USA.
authors.forename: L
authors.initials: L
authors.lastname: Ma
authors.forename: B
authors.initials: B
authors.lastname: Hu
authors.forename: A L
authors.initials: AL
authors.lastname: Kenter
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D001667:Binding, Competitive / Q000276:immunology; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D005260:Female; D015326:Gene Rearrangement, B-Lymphocyte, Heavy Chain / Q000235:genetics; D018257:Helix-Loop-Helix Motifs / Q000235:genetics / Q000276:immunology; D007143:Immunoglobulin Heavy Chains / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D007134:Immunoglobulin Switch Region; D016393:Lymphoma, B-Cell; D051379:Mice; D008807:Mice, Inbred BALB C; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D007143:Immunoglobulin Heavy Chains; D014157:Transcription Factors; C075668:Tcf3 protein, mouse