DNA damage-signaling, homologous recombination and genetic mutation induced by 5-azacytidine and DNA-protein crosslinks in Escherichia coli.
DNA damage-signaling, homologous recombination and genetic mutation induced by 5-azacytidine and DNA-protein crosslinks in Escherichia coli.
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DOI：
10.1016/j.mrfmmm.2021.111742
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发表时间：
2021-01
期刊：
影响因子：
--
通讯作者：
Lovett ST
中科院分区：
文献类型：
--
作者：
Klaric JA;Glass DJ;Perr EL;Reuven AD;Towne MJ;Lovett ST
DNA和蛋白质之间的共价连接产生高毒性病变，可由常用的化疗药物、内部和外部化学物质以及辐射引起。在这项研究中，我们使用大肠杆菌，研究了5-氮杂胞苷（5-azaC）的后果，它在自身和Dcm胞嘧啶甲基转移酶蛋白之间捕获共价复合物。DNA蛋白交联依赖效应可以通过野生型而非dcm∆菌株产生的效应来确定。我们发现5-azaC诱导细菌DNA损伤反应并刺激同源重组，其中一个成分依赖于dcm。5- azaC强烈增强了不完全反向重复（QP）的模板转换，这种增强完全依赖于dcm，不依赖于双链断裂修复。SOS反应有助于改善5-azaC的诱变作用，但这不是SOS诱导的DNA聚合酶的结果，因为它们的诱导，尤其是PolIV，似乎刺激了qp相关的诱变。5-azaC诱导的QP突变体的恢复也需要细胞分裂调节剂SulA。在缺乏Lon蛋白酶的情况下，dcm依赖性qp诱变显著升高，表明它可能在DPC耐受性中发挥作用。在短串联重复序列上的缺失，同样发生在复制模板切换中，5-azaC提高了，但只是适度地提高了。我们在敏感突变体（如recA、recB和lon）中发现了5- azaC对dcm依赖型和非依赖型杀伤的证据；同源重组和缺失突变也在一定程度上受到5-azaC不依赖于dcm的影响。这是由不同的蛋白质/DNA交联还是由另一种形式的DNA损伤引起的尚不清楚。
Covalent linkage between DNA and proteins produces highly toxic lesions and can be caused by commonly used chemotherapeutic agents, by internal and external chemicals and by radiation. In this study, using Escherichia coli, we investigate the consequences of 5-azacytidine (5-azaC), which traps covalent complexes between itself and the Dcm cytosine methyltransferase protein. DNA protein crosslink-dependent effects can be ascertained by effects that arise in wild-type but not in dcm∆ strains. We find that 5-azaC induces the bacterial DNA damage response and stimulates homologous recombination, a component of which is Dcm-dependent. Template-switching at an imperfect inverted repeat (“quasipalindrome”, QP) is strongly enhanced by 5- azaC and this enhancement was entirely Dcm-dependent and independent of double-strand break repair. The SOS response helps ameliorate the mutagenic effect of 5-azaC but this is not a result of SOS-induced DNA polymerases since their induction, especially PolIV, seems to stimulate QP-associated mutagenesis. Cell division regulator SulA was also required for recovery of QP mutants induced by 5-azaC. In the absence of Lon protease, Dcm-dependent QP-mutagenesis is strongly elevated, suggesting it may play a role in DPC tolerance. Deletions at short tandem repeats, which occur likewise by a replication template-switch, are elevated, but only modestly, by 5-azaC. We see evidence for Dcm-dependent and-independent killing by 5- azaC in sensitive mutants, such as recA, recB, and lon; homologous recombination and deletion mutations are also stimulated in part by a Dcm-independent effect of 5-azaC. Whether this occurs by a different protein/DNA crosslink or by an alternative form of DNA damage is unknown.
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影响因子：
14.9
作者：
Butala M;Busby SJ;Lee DJ
通讯作者：
Lee DJ
影响因子：
64.8
作者：
Cox, MM;Goodman, MF;Marians, KJ
通讯作者：
Marians, KJ
DOI：
10.1016/s0027-5107(99)00099-8
发表时间：
1999-08-11
影响因子：
2.3
作者：
Doiron, KMJ;Lavigne-Nicolas, J;Cupples, CG
通讯作者：
Cupples, CG
DOI：
10.1073/pnas.120163297
发表时间：
2000-06-06
影响因子：
11.1
作者：
Datsenko, KA;Wanner, BL
通讯作者：
Wanner, BL
影响因子：
64.8
作者：
Garaycoechea, Juan I.;Crossan, Gerry P.;Patel, Ketan J.
通讯作者：
Patel, Ketan J.