5S rRNA gene transcription factor IIIA alters the helical configuration of DNA.
5S rRNA gene transcription factor IIIA alters the helical configuration of DNA.
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5S rRNA 基因转录因子 IIIA 改变 DNA 的螺旋构型。
DOI：
10.1073/pnas.80.7.1862
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发表时间：
1983
影响因子：
11.1
通讯作者：
Gottesfeld,JM
中科院分区：
文献类型：
--
作者：
Reynolds,WF;Gottesfeld,JM
在转录因子（TF）IIIA存在下，非洲爪蟾5S质粒DNA（pX 1 o 8）的松弛减少了DNA的连接数。用质粒pMB 9或克隆的B型肝炎病毒DNA进行的平行实验表明TF具有一定程度的非特异性解旋;然而，在pX 1 o 8中观察到的60%的效应是由于TF IIIA与5S rRNA基因内部启动子序列的特异性相互作用。解旋的程度（每个TF IIIA结合位点0.2-0.4个螺旋转角）与50个碱基对TF结合位点的完全变性不一致;然而，它与螺旋旋转的变化、每个结合位点2-4个核苷酸的变性或DNA包裹蛋白质核心一致。我们发现，蛋白质以外的TF IIIA（牛血清白蛋白和核糖核酸酶）有没有影响的DNA连接数时，存在于放松和解旋活动与TF是热不稳定的。这些结果表明，TF IIIA可能通过改变5S DNA的螺旋构型来促进转录。
Relaxation of Xenopus 5S plasmid DNA (pX1o8) in the presence of transcription factor (TF) IIIA reduces the linking number of the DNA. Parallel experiments with plasmid pMB9 or cloned hepatitis B viral DNA indicate a degree of non-specific unwinding by TF; however, 60% of the effect observed for pX1o8 is due to specific interaction of TF IIIA with the 5S rRNA gene internal promoter sequence. The extent of unwinding (0.2-0.4 helical turn per TF IIIA binding site) is not consistent with the complete denaturation of the 50-base-pair TF binding site; however, it is consistent with a change in helix rotation, denaturation of 2-4 nucleotides per binding site, or DNA wrapping about a protein core. We show that proteins other than TF IIIA (bovine serum albumin and RNase) have no effect on the linking number of DNA when present during relaxation and that the unwinding activity associated with TF is heat labile. These results suggest that TF IIIA may facilitate transcription by altering the helical configuration of 5S DNA.