Promoter opening via a DNA fork junction binding activity
Promoter opening via a DNA fork junction binding activity
复制标题
DOI：
10.1073/pnas.95.20.11655
复制
发表时间：
1998-09-29
影响因子：
11.1
通讯作者：
Gralla, JD
中科院分区：
文献类型：
--
作者：
Guo, Y;Gralla, JD
转录起始的限速步骤通常是打开启动子DNA以暴露模板链。开放受到严格监管，但它是如何发生的尚不清楚。这些实验确定了一种活性，识别特定的DNA叉结，并表明它对细菌启动子打开至关重要。这个活动是特定于序列和结构的；它识别构成开放络合物上游双链/单链边界的碱基。已知降低打开率的启动子突变导致叉结结合亲和力的类似降低。该活性作用于建立融化DNA的上游边界，并与两个单链DNA结合活性一起工作，分别识别两条融化的DNA链。连接结合活性包含在全酶的sigma因子成分中。这种活性既存在于典型的原核生物转录系统中，也存在于对增强子有反应并需要ATP的真核类细菌系统中。因此，由叉结结合催化的DNA打开可能发生在DNA必须打开才能复制的各种系统中。
The rate-limiting step in transcriptional initiation typically is opening the promoter DNA to expose the template strand. Opening is tightly regulated, but how it occurs is not known. These experiments identify an activity, recognition of specific DNA fork junctions, and suggest that it is critical to bacterial promoter opening. This activity is both sequence and structure specific; it recognizes the bases that constitute the upstream double-stranded/single-stranded boundary of the open complex. Promoter mutations known to reduce opening rates lead to comparable reductions in fork junction binding affinity. The activity acts to establish the upstream boundary of melted DNA and works in conjunction with two single-stranded DNA binding activities that recognize separately the two melted strands. The junction binding activity is contained within the sigma factor component of the holoenzyme. The activity occurs in both a typical prokaryotic transcription system and in a eukaryotic-like bacterial system that responds to enhancers and needs ATP, Thus DNA opening catalyzed by fork junction binding may occur in a variety of systems in which DNA must be opened to be copied.