Genetic Recombination in Bacillus subtilis 168: Contribution of Holliday Junction Processing Functions in Chromosome Segregation

Begoña Carrasco; M. Castillo Cozar; Rudi Lurz; Juan C. Alonso; Silvia Ayora

doi:10.1128/jb.186.17.5557-5566.2004

Genetic Recombination in Bacillus subtilis 168: Contribution of Holliday Junction Processing Functions in Chromosome Segregation

Journal of Bacteriology ◽

10.1128/jb.186.17.5557-5566.2004 ◽

2004 ◽

Vol 186 (17) ◽

pp. 5557-5566 ◽

Cited By ~ 41

Author(s):

Begoña Carrasco ◽

M. Castillo Cozar ◽

Rudi Lurz ◽

Juan C. Alonso ◽

Silvia Ayora

Keyword(s):

Dna Repair ◽

Bacillus Subtilis ◽

Genetic Recombination ◽

Holliday Junction ◽

Dna Helicases ◽

Chromosomal Segregation ◽

Dna Damaging Agents ◽

Bacillus Subtilis 168 ◽

Repair Deficiency ◽

Repair Defect

ABSTRACT Bacillus subtilis mutants classified within the ε (ruvA, ΔruvB, ΔrecU, and recD) and η (ΔrecG) epistatic groups, in an otherwise rec+ background, render cells impaired in chromosomal segregation. A less-pronounced segregation defect in ΔrecA and Δsms (ΔradA) cells was observed. The repair deficiency of addAB, ΔrecO, ΔrecR, recH, ΔrecS, and ΔsubA cells did not correlate with a chromosomal segregation defect. The sensitivity of ε epistatic group mutants to DNA-damaging agents correlates with ongoing DNA replication at the time of exposure to the agents. The Δsms (ΔradA) and ΔsubA mutations partially suppress the DNA repair defect in ruvA and recD cells and the segregation defect in ruvA and ΔrecG cells. The Δsms (ΔradA) and ΔsubA mutations partially suppress the DNA repair defect of ΔrecU cells but do not suppress the segregation defect in these cells. The ΔrecA mutation suppresses the segregation defect but does not suppress the DNA repair defect in ΔrecU cells. These results result suggest that (i) the RuvAB and RecG branch migrating DNA helicases, the RecU Holliday junction (HJ) resolvase, and RecD bias HJ resolution towards noncrossovers and that (ii) Sms (RadA) and SubA proteins might play a role in the stabilization and or processing of HJ intermediates.

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Genetic Recombination in Bacillus subtilis 168: Effect of ΔhelD on DNA Repair and Homologous Recombination

Journal of Bacteriology ◽

10.1128/jb.183.19.5772-5777.2001 ◽

2001 ◽

Vol 183 (19) ◽

pp. 5772-5777 ◽

Cited By ~ 14

Author(s):

Begoña Carrasco ◽

Silvia Fernández ◽

Marie-Agnes Petit ◽

Juan C. Alonso

Keyword(s):

Dna Repair ◽

Bacillus Subtilis ◽

Homologous Recombination ◽

Genetic Recombination ◽

Methyl Methanesulfonate ◽

Plasmid Transformation ◽

Dna Damaging Agents ◽

Bacillus Subtilis 168 ◽

Recombination Repair ◽

Helicase Iv

ABSTRACT The B. subtilis ΔhelD allele rendered cells proficient in transformational recombination and moderately sensitive to methyl methanesulfonate when present in an otherwise Rec+ strain. The ΔhelD allele was introduced into rec-deficient strains representative of the α (recF strain), β (addA addB), γ (recH), ɛ (ΔrecU), and ζ (ΔrecS) epistatic groups. The ΔhelDmutation increased the sensitivity to DNA-damaging agents ofaddAB, ΔrecU, and ΔrecS cells, did not affect the survival ofrecH cells, and decreased the sensitivity ofrecF cells. ΔhelD also partially suppressed the DNA repair phenotype of other mutations classified within the α epistatic group, namely the recL, ΔrecO, and recR mutations. The ΔhelD allele marginally reduced plasmid transformation (three- to sevenfold) of mutations classified within the α, β, and γ epistatic groups. Altogether, these data indicate that the loss of helicase IV might stabilize recombination repair intermediates formed in the absence of recFLOR and renderrecFLOR, addAB, andrecH cells impaired in plasmid transformation.

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Genetic Recombination in Bacillus subtilis 168: Effects of recU and recSMutations on DNA Repair and Homologous Recombination

Journal of Bacteriology ◽

10.1128/jb.180.13.3405-3409.1998 ◽

1998 ◽

Vol 180 (13) ◽

pp. 3405-3409 ◽

Cited By ~ 43

Author(s):

Silvia Fernández ◽

Alexei Sorokin ◽

Juan C. Alonso

Keyword(s):

Dna Repair ◽

Bacillus Subtilis ◽

Selectable Marker ◽

Genetic Recombination ◽

Null Alleles ◽

Single Mutation ◽

Coding Regions ◽

Dna Damaging Agents ◽

Bacillus Subtilis 168 ◽

Intramolecular Recombination

ABSTRACT Bacillus subtilis recombination-deficient mutants were constructed by inserting a selectable marker (cat gene) into the yppB and ypbC coding regions. TheyppB:cat and ypbC:catnull alleles rendered cells sensitive to DNA-damaging agents, impaired plasmid transformation (25- and 100-fold), and moderately affected chromosomal transformation when present in an otherwise Rec+ B. subtilis strain. The yppBgene complemented the defect of the recG40 strain.yppB and ypbC and their respective null alleles were termed “recU” and “recU1” (recU:cat) and “recS” and “recS1” (recS:cat), respectively. The recU and recS mutations were introduced into rec-deficient strains representative of the α (recF), β (addA5 addB72), γ (recH342), and ɛ (recG40) epistatic groups. The recU mutation did not modify the sensitivity ofrecH cells to DNA-damaging agents, but it did affect inter- and intramolecular recombination in recH cells. TherecS mutation did not modify the sensitivity ofaddAB cells to DNA-damaging agents, and it marginally affected recF, recH, and recUcells. The recS mutation markedly reduced (about 250-fold) intermolecular recombination in recH cells, and there were reductions of 10- to 20-fold in recF, addAB, and recU cells. Intramolecular recombination was blocked inrecS recF, recS addAB, and recS recU cells. RecU and RecS have no functional counterparts inEscherichia coli. Altogether, these data indicate that therecU and recS proteins are required for DNA repair and intramolecular recombination and that the recF(α epistatic group), addAB (β), recH (γ),recU (ɛ), and recS genes provide overlapping activities that compensate for the effects of single mutation. We tentatively placed recS within a new group, termed “ζ.”

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