Ma L, Hu B, Kenter A L
Department of Microbiology and Immunology (M/C 790), University of Illinois College of Medicine, Chicago 60612-7344, USA.
Int Immunol. 1997 Jul;9(7):1021-9. doi: 10.1093/intimm/9.7.1021.
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.
SNAP是一种DNA结合蛋白，对Sγ转换区具有特异性。两个E-2盒共有结合基序位于SNAP识别位点内。直接结合分析和竞争结合分析表明，E47转录因子的截短形式E47S能够与SNAP结合基序发生特异性相互作用。E47S与p1.Sγ3.A.1探针结合的甲基化干扰模式与先前获得的SNAP结合活性的模式相似，也与在microE5探针上发现的E47S的模式相关。纯化的E47S与SNAP识别基序的相互作用是协同的，形成的复合物迁移速度比E47S同二聚体复合物慢。在凝胶迁移实验中，SNAP与在BCF-1中发现的全长E47同二聚体的迁移位置不同，竞争结合结果存在差异，且与抗E47抗体具有独特的反应性，从而得以区分。根据Sγ3 A位点DNA上相似的甲基化干扰模式及其与抗E47单克隆抗体的反应性判断，SNAP与E47相关。抗E47抗体可阻断SNAP与其同源位点的结合，而抗E47抗体可使与microE5识别位点结合的E47同二聚体发生超迁移。因此，SNAP可能是一种包含E47或高度相关蛋白的异源寡聚体。
