Ephrussi A, Church G M, Tonegawa S, Gilbert W
Science. 1985 Jan 11;227(4683):134-40. doi: 10.1126/science.3917574.
The mouse heavy chain immunoglobulin gene contains a tissue-specific enhancer. The enhancer and flanking sequences were studied in vivo by carrying out dimethyl sulfate protection experiments on living cells, in combination with genomic sequencing. Relative to reactions on naked DNA, there are changes (protections and enhancements) in the reactivity of guanine residues to dimethyl sulfate within the enhancer sequence in myeloma, B, and early B cells, whereas virtually no alterations appear in cells of non-B lineage. Most of the affected residues are in four clusters, in sequences homologous to the octamer 5'CAGGTGGC 3' (C, cytosine; A, adenine; G. guanine; T, thymine). The alterations in the pattern of G reactivity are consistent with the tissue-specific binding of molecules to the mouse immunoglobulin heavy chain enhancer.
小鼠重链免疫球蛋白基因包含一个组织特异性增强子。通过对活细胞进行硫酸二甲酯保护实验并结合基因组测序，对增强子及其侧翼序列进行了体内研究。相对于对裸露DNA的反应，在骨髓瘤细胞、B细胞和早期B细胞中，增强子序列内鸟嘌呤残基对硫酸二甲酯的反应性发生了变化（保护和增强），而在非B谱系细胞中几乎没有改变。大多数受影响的残基位于四个簇中，其序列与八聚体5'CAGGTGGC 3'（C，胞嘧啶；A，腺嘌呤；G，鸟嘌呤；T，胸腺嘧啶）同源。G反应模式的改变与分子与小鼠免疫球蛋白重链增强子的组织特异性结合一致。
