Inhibition of the SOS response of Escherichia coli by the Ada protein
Induction of the adaptive response by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) caused a decrease in the UV-mediated expression of both recA and sfiA genes but not of the umuDC gene. On the other hand, the adaptive response did not affect the temperature-promoted induction of SOS response in a RecA441 mutant. The inhibitory effect on the UV-triggered expression of the recA and sfiA genes was not dependent on either the alkA gene or the basal level of RecA protein, but rather required the ada gene. Furthermore, an increase in the level of the Ada protein, caused by the runaway plasmid pYN3059 in which the ada gene is regulated by the lac promoter, inhibited UV-mediated recA gene expression even in cells to which the MNNG-adaptive treatment had not been applied. This inhibitory effect of the adaptive pretreatment was not observed either in RecBC- strains or in RecBC mutants lacking exonuclease V-related nuclease activity. However, RecF- mutants showed an adaptive response-mediated decrease in UV-promoted induction of the recA gene.
- Research Organization:
- Autonomous Univ. of Barcelona, Bellaterra (Spain)
- OSTI ID:
- 5194754
- Journal Information:
- J. Bacteriol.; (United States), Vol. 170:3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ESCHERICHIA COLI
GENE REGULATION
NITROSO COMPOUNDS
BIOLOGICAL EFFECTS
ALKYLATION
BIOLOGICAL ADAPTATION
DNA REPAIR
GENES
INHIBITION
NUCLEASES
PROTEINS
ULTRAVIOLET RADIATION
BACTERIA
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CHEMICAL REACTIONS
ELECTROMAGNETIC RADIATION
ENZYMES
ESTERASES
HYDROLASES
MICROORGANISMS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOSPHODIESTERASES
RADIATIONS
RECOVERY
REPAIR
560300* - Chemicals Metabolism & Toxicology
560130 - Radiation Effects on Microorganisms