Peterson C L, Orth K, Calame K L
Mol Cell Biol. 1986 Dec;6(12):4168-78. doi: 10.1128/mcb.6.12.4168-4178.1986.
Seven protein-binding sites on the immunoglobulin heavy-chain (IgH) enhancer element have been identified by exonuclease III protection and gel retardation assays. It appears that the seven sites bind a minimum of four separate proteins. Three of these proteins also bind to other enhancers or promoters, but one protein seems to recognize exclusively IgH enhancer sequences. A complex of four binding sites, recognized by different proteins, is located within one 80-base-pair region of IgH enhancer DNA. Close juxtaposition of enhancer proteins may allow protein-protein interactions or be part of a mechanism for modulating enhancer protein activity. All IgH enhancer-binding proteins identified in this study were found in extracts from nonlymphoid as well as lymphoid cells. These data provide the first direct evidence that multiple proteins bind to enhancer elements and that while some of these proteins recognize common elements of many enhancers, others have more limited specificities.
通过核酸外切酶III保护试验和凝胶阻滞试验，已在免疫球蛋白重链（IgH）增强子元件上鉴定出七个蛋白质结合位点。似乎这七个位点至少结合四种不同的蛋白质。其中三种蛋白质也与其他增强子或启动子结合，但有一种蛋白质似乎只识别IgH增强子序列。由不同蛋白质识别的四个结合位点组成的复合物位于IgH增强子DNA的一个80碱基对区域内。增强子蛋白的紧密并列可能允许蛋白质-蛋白质相互作用，或者是调节增强子蛋白活性机制的一部分。在本研究中鉴定出的所有IgH增强子结合蛋白在非淋巴细胞和淋巴细胞的提取物中均有发现。这些数据提供了首个直接证据，表明多种蛋白质与增强子元件结合，并且虽然其中一些蛋白质识别许多增强子的共同元件，但其他蛋白质具有更有限的特异性。
