Webb C F, Das C, Eneff K L, Tucker P W
Department of Immunobiology, Oklahoma Medical Research Foundation, Oklahoma City 73104.
Mol Cell Biol. 1991 Oct;11(10):5206-11. doi: 10.1128/mcb.11.10.5206-5211.1991.
In the accompanying report (C. F. Webb, C. Das, S. Eaton, K. Calame, and P. Tucker, Mol. Cell. Biol. 11:5197-5205, 1991), we characterize B-cell-specific protein-DNA interactions at -500 and -200 bp upstream of the mu immunoglobulin heavy chain promoter whose abundances were increased by interleukin-5 plus antigen. Because of the high A + T/G + C ratio of these sequences and the consistent findings by others that enhancer- and promoterlike regions are often located near matrix-associated regions, we asked whether these sequences might also be involved in binding to the nuclear matrix. Indeed, DNA fragments containing the -500 binding site were bound by nuclear matrix proteins. Furthermore, UV cross-linking studies showed that the DNA binding site for interleukin-5-plus-antigen-inducible proteins could also bind to proteins solubilized from the nuclear matrix. Nuclear matrix-associated sequences have also been demonstrated on either side of the intronic immunoglobulin heavy chain enhancer. Our data suggest a topological model by which interactions among proteins bound to the promoter and distal enhancer sequences might occur.
在随附的报告中（C.F. 韦伯、C. 达斯、S. 伊顿、K. 卡拉梅和P. 塔克，《分子与细胞生物学》11:5197 - 5205，1991年），我们对μ免疫球蛋白重链启动子上游 - 500和 - 200碱基对处的B细胞特异性蛋白质 - DNA相互作用进行了表征，这些相互作用的丰度因白细胞介素 - 5加抗原而增加。由于这些序列的A + T/G + C比例很高，且其他人一致发现增强子样和启动子样区域通常位于与核基质相关的区域附近，我们询问这些序列是否也可能参与与核基质的结合。事实上，含有 - 50０结合位点的DNA片段被核基质蛋白结合。此外，紫外线交联研究表明，白细胞介素 - 5加抗原诱导蛋白的DNA结合位点也能与从核基质中溶解的蛋白质结合。在免疫球蛋白重链内含子增强子的两侧也已证实存在与核基质相关的序列。我们的数据提出了一个拓扑模型，通过该模型，与启动子和远端增强子序列结合的蛋白质之间可能会发生相互作用。
