Dataset Information

Escherichia coli DNA repair genes radA and sms are the same gene.

ABSTRACT: Escherichia coli strains carrying radA100 or sms mutations were identical in their sensitivities to either methyl methanesulfonate or UV radiation treatment and in their plasmid complementation patterns for UV radiation survival. DNA sequencing analysis of the radA mutant and radA+ strains and comparison of their sequences with the published sms gene sequence showed the radA mutant to differ only by a G-to-A transition mutation, which is predicted to change a cysteine in a zinc-finger motif to tyrosine. The sms gene is concluded to be identical to the previously described radA gene.

SUBMITTER: Song Y

PROVIDER: S-EPMC178295 | biostudies-other | 1996 Aug

REPOSITORIES: biostudies-other

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Escherichia coli DNA repair genes radA and sms are the same gene.

Song Y Y Sargentini N J NJ

Journal of bacteriology 19960801 16

Escherichia coli strains carrying radA100 or sms mutations were identical in their sensitivities to either methyl methanesulfonate or UV radiation treatment and in their plasmid complementation patterns for UV radiation survival. DNA sequencing analysis of the radA mutant and radA+ strains and comparison of their sequences with the published sms gene sequence showed the radA mutant to differ only by a G-to-A transition mutation, which is predicted to change a cysteine in a zinc-finger motif to t ...[more]

PMID: 8759876

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Project description:Bacteria, yeast and human cancer cells possess mechanisms of mutagenesis upregulated by stress responses. Stress-inducible mutagenesis potentially accelerates adaptation, and may provide important models for mutagenesis that drives cancers, host pathogen interactions, antibiotic resistance and possibly much of evolution generally. In Escherichia coli repair of double-strand breaks (DSBs) becomes mutagenic, using low-fidelity DNA polymerases under the control of the SOS DNA-damage response and RpoS general stress response, which upregulate and allow the action of error-prone DNA polymerases IV (DinB), II and V to make mutations during repair. Pol IV is implied to compete with and replace high-fidelity DNA polymerases at the DSB-repair replisome, causing mutagenesis. We report that up-regulated Pol IV is not sufficient for mutagenic break repair (MBR); damaged bases in the DNA are also required, and that in starvation-stressed cells, these are caused by reactive-oxygen species (ROS). First, MBR is reduced by either ROS-scavenging agents or constitutive activation of oxidative-damage responses, both of which reduce cellular ROS levels. The ROS promote MBR other than by causing DSBs, saturating mismatch repair, oxidizing proteins, or inducing the SOS response or the general stress response. We find that ROS drive MBR through oxidized guanines (8-oxo-dG) in DNA, in that overproduction of a glycosylase that removes 8-oxo-dG from DNA prevents MBR. Further, other damaged DNA bases can substitute for 8-oxo-dG because ROS-scavenged cells resume MBR if either DNA pyrimidine dimers or alkylated bases are induced. We hypothesize that damaged bases in DNA pause the replisome and allow the critical switch from high fidelity to error-prone DNA polymerases in the DSB-repair replisome, thus allowing MBR. The data imply that in addition to the indirect stress-response controlled switch to MBR, a direct cis-acting switch to MBR occurs independently of DNA breakage, caused by ROS oxidation of DNA potentially regulated by ROS regulators.

Dataset Information

Escherichia coli DNA repair genes radA and sms are the same gene.

Publications

Escherichia coli DNA repair genes radA and sms are the same gene.

Similar Datasets

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