Suppression of constitutive SOS expression by recA4162 (I298V) and recA4164 (L126V) requires UvrD and RecX in Escherichia coli K-12.
Suppression of constitutive SOS expression by recA4162 (I298V) and recA4164 (L126V) requires UvrD and RecX in Escherichia coli K-12.
复制标题
在大肠杆菌 K-12 中，recA4162 (I298V) 和 recA4164 (L126V) 抑制 SOS 的组成型表达需要 UvrD 和 RecX。
DOI：
10.1111/j.1365-2958.2009.06765.x
复制
发表时间：
2009
影响因子：
3.6
通讯作者：
Sandler,StevenJ
中科院分区：
文献类型：
--
作者：
Long,JarukitE;Renzette,Nicholas;Sandler,StevenJ
检测DNA损伤和启动修复DNA损伤的遗传反应对细胞存活至关重要。在大肠杆菌中，RecA在DNA损伤产生的ssDNA上聚合，产生RecA-DNA细丝，该细丝与莱克萨阻遏物相互作用，诱导SOS反应。RecA丝的稳定性受到RecX和UvrD的负调控。recA 730（E38 K）和recA 4142（F217 Y）组成型表达SOS反应。recA 4162（I298 V）和recA 4164（L126 V）是组成型SOS表型recA 730的基因内抑制因子。在此，表明这些抑制子不是等位基因特异性的，并且可以抑制recA 730和recA 4142在顺式和反式中的SOSC表达。recA 4162和recA 4164单突变体（以及recA 730和recA 4142衍生物）是Rec+，UV R，并且能够像野生型一样在UV处理后诱导SOS反应。在所测试的四个双突变体中的两个（recA 730，4164和recA 4142，4162）中，UvrD和RecX是抑制所需的。为了解释这些数据，一个模型表明recA等位基因通过模拟诱导SOS的RecA细丝结构来促进SOSC表达，而抑制等位基因模拟SOS末端的RecA细丝。UvrD和RecX被吸引到这些后者的结构，以帮助拆除或破坏RecA细丝。
Sensing DNA damage and initiation of genetic responses to repair DNA damage are critical to cell survival. InEscherichia coli, RecA polymerizes on ssDNA produced by DNA damage creating a RecA–DNA filament that interacts with the LexA repressor inducing the SOS response. RecA filament stability is negatively modulated by RecX and UvrD.recA730(E38K) andrecA4142(F217Y) constitutively express the SOS response.recA4162(I298V) andrecA4164(L126V) are intragenic suppressors of the constitutive SOS phenotype ofrecA730. Herein, it is shown that these suppressors are not allele specific and can suppress SOSCexpression ofrecA730andrecA4142 in cisandin trans.recA4162andrecA4164single mutants (and therecA730andrecA4142derivatives) are Rec+, UVRand are able to induce the SOS response after UV treatment like wild‐type. UvrD and RecX are required for the suppression in two (recA730,4164andrecA4142,4162) of the four double mutants tested. To explain the data, one model suggests thatrecACalleles promote SOSCexpression by mimicking RecA filament structures that induce SOS and the suppressor alleles mimic RecA filament at end of SOS. UvrD and RecX are attracted to these latter structures to help dismantle or destabilize the RecA filament.