DNA Polymerases ImuC and DinB Are Involved in DNA Alkylation Damage Tolerance in Pseudomonas aeruginosa and Pseudomonas putida

Abstract

Translesion DNA synthesis (TLS), facilitated by low-fidelity polymerases, is an important DNA damage tolerance mechanism. Here, we investigated the role and biological function of TLS polymerase ImuC (former DnaE2), generally present in bacteria lacking DNA polymerase V, and TLS polymerase DinB in response to DNA alkylation damage in Pseudomonas aeruginosa and P. putida. We found that TLS DNA polymerases ImuC and DinB ensured a protective role against N- and O-methylation induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in both P. aeruginosa and P. putida. DinB also appeared to be important for the survival of P. aeruginosa and rapidly growing P. putida cells in the presence of methyl methanesulfonate (MMS). The role of ImuC in protection against MMS-induced damage was uncovered under DinB-deficient conditions. Apart from this, both ImuC and DinB were critical for the survival of bacteria with impaired base excision repair (BER) functions upon alkylation damage, lacking DNA glycosylases AlkA and/or Tag. Here, the increased sensitivity of imuCdinB double deficient strains in comparison to single mutants suggested that the specificity of alkylated DNA lesion bypass of DinB and ImuC might also be different. Moreover, our results demonstrated that mutagenesis induced by MMS in pseudomonads was largely ImuC-dependent. Unexpectedly, we discovered that the growth temperature of bacteria affected the efficiency of DinB and ImuC in ensuring cell survival upon alkylation damage. Taken together, the results of our study disclosed the involvement of ImuC in DNA alkylation damage tolerance, especially at low temperatures, and its possible contribution to the adaptation of pseudomonads upon DNA alkylation damage via increased mutagenesis.

ImuB and ImuC contribute to UV‐induced mutagenesis as part of the SOS regulon in Pseudomonas aeruginosa

“…Thus, both factors may probably fulfill different roles in different bacterial species. Particularly in P. aeruginosa , ImuC has been reported to be involved in UV‐induced mutagenesis (Sanders et al ) and in coping with DNA alkylation damage, along with ImuA and ImuB (Jatsenko et al ). Consistent with previous reports, our observations indicate that ImuC significantly contribute to the UV‐induced mutator phenotype in P. aeruginosa .…”

“…Inspection of the P. aeruginosa genome reveals the presence of a dinB ‐enconded Pol IV and also of a three‐gene cassette imuA ‐ imuB ‐ imuC (Abella et al ), Pol IV being the best characterized. It has been established in vitro that Pol IV constitutes a LexA‐dependent error‐prone DNA polymerase (Sanders et al ), being involved in DNA oxidative and alkylation induced mutagenesis (Jatsenko et al ) and in the acquisition of prototypic CF adaptive phenotypes such as mucoidy and antibiotic resistance (Moyano et al ). However, data about the role of imuA ‐ imuB ‐ imuC cassette in P. aeruginosa mutagenesis is still incipient and speckled in the literature.…”

“…However, data about the role of imuA ‐ imuB ‐ imuC cassette in P. aeruginosa mutagenesis is still incipient and speckled in the literature. ImuC contributes to DNA alkylation (Jatsenko et al ) and UV‐induced mutagenesis (Sanders et al ), and the transcription of both, imuB and imuC , was shown to be unevenly increased upon exposure of P. aeruginosa to the SOS‐inducing antibiotic ciprofloxacin (Cirz et al ). In this study, we have investigated the role of ImuB and ImuC in P. aeruginosa DNA damage induced mutagenesis.…”

Narrative of a versatile and adept species Pseudomonas putida

“…Elucidation of the involvement of specialized DNA polymerases in mutagenic processes in P. putida revealed that whether the DNA synthesis carried out by a particular specialized DNA polymerase is error-prone or accurate, depends on a type of DNA damage. For instance, although in stationaryphase mutagenesis assays Pol IV is error-prone [161] and DnaE2 reduces accumulation of mutations in starving P. putida populations [164], upon DNA alkylation damage, in opposite, the DnaE2-dependent replication is error-prone and the Pol IV-dependent replication accurate [165]. It has been suggested that the presence of DnaE2 operon in P. putida chromosome substitutes the lack of Pol V genes [166,167].…”

Papel dos mecanismos de reparo de DNA na resposta de <i>Pseudomonas aeruginosa</i> aos antimicrobianos Cirprofloxacina e Ceftazidima.

“…tuberculosis (GALHARDO et al, 2005;WARNER et al, 2010) são essenciais para o apropriado funcionamento do sistema (JATSENKO et al, 2017).…”