Repressor induced site-specific binding of HU for transcriptional regulation
Repressor induced site-specific binding of HU for transcriptional regulation
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DOI：
10.1093/emboj/16.12.3666
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发表时间：
1997-06-16
期刊：
影响因子：
11.4
通讯作者：
Adhya, S
中科院分区：
文献类型：
--
作者：
Aki, T;Adhya, S
两个重叠的gal启动子的转录被gal抑制子与启动子两侧的双部分gal操作子O-E和O-I结合而抑制。同时抑制gal启动子也需要细菌组蛋白样蛋白HU作为辅助因子。利用铁edta偶联HU的足迹实验表明，HU与gal DNA的结合具有定向特异性，并且特异性地依赖于GalR与O-E和O-I的结合。我们提出，HU与GalR一起形成一个含有DNA环的特定核蛋白高阶复合物，通过这种方式，HU使启动子变形，使后者对转录起始失活，同时对诱导剂保持敏感。gal抑制的例子为研究“浓缩”DNA如何变得可用于转录提供了一个模型。
Transcription from two overlapping gal promoters is repressed by Gal repressor binding to bipartite gal operators, O-E and O-I, which flank the promoters. Concurrent repression of the gal promoters also requires the bacterial histone-like protein HU which acts as a co-factor. Footprinting experiments using iron-EDTA-coupled HU show that HU binding to gal DNA is orientation specific and is specifically dependent upon binding of GalR to both O-E and O-I. We propose that HU, in concert with GalR, forms a specific nucleo-protein higher order complex containing a DNA loop, This way, HU deforms the promoter to make the latter inactive for transcription initiation while remaining sensitive to inducer. The example of gal repression provides a model for studying how a 'condensed' DNA becomes available for transcription.