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. 2000 Mar;182(5):1427–1431. doi: 10.1128/jb.182.5.1427-1431.2000

FIG. 1.

FIG. 1

Requirement for recombination genes required for the mutA phenotype detected by a colony papillation assay based on reversion of the lacZ mutant to a lacZ+ phenotype as described in detail elsewhere (15). Strains were streaked on minimal agar-based indicator plates (papillation plates) and incubated for 5 days at 37°C before observation. (A) Effect of recC, recD, and ruvC mutations on expression of the mutA mutator phenotype. Sectors: 1, E. coli CC105 (wild-type) control cells; 2, CC105mutA cells showing characteristically high papillation; 3, E. coli LR500 (CC105 recC); 4, E. coli LR600 (CC105mutA recC); 5, E. coli LR700 (CC105 recD); 6, E. coli LR800 (CC105mutA recD); 7, E. coli LR130 (CC105 ruvC); 8, E. coli LR140 (CC105mutA ruvC). (B) Overexpression of recBCD genes restores the mutA phenotype in mutA recC cells. Sectors: 1, CC105 control; 2, CC105mutA, showing high papillation; 3, LR500 (CC105 recC)/pDWS2(recB+ -C+ -D+); 4, 5, and 6, LR600 (CC105mutA recC [three isolates])/pDWS2(recB+ -C+ -D+) showing restoration of papillation. (C) Effect of ruvA mutation on the expression of the mutA mutator phenotype. Sectors: 1, CC105mutA showing high papillation characteristic of mutA cells; 2, CC105 control with few papillae; 3 and 4, E. coli LR110 (CC105 ruvA [two isolates]) controls; 5 and 6, E. coli LR120 (CC105mutA ruvA [two isolates]) showing that the mutA phenotype is abolished in ruvA cells. (D) Effect of recF, recO, and recR mutations on the expression of the mutA mutator phenotype. Sectors: 1, CC105mutA showing characteristically high papillation; 2, CC105 control, showing few papillae; 3, E. coli AM115 (CC105 recF); 4, E. coli AM117 (CC105 recO) showing few papillae; 5, E. coli AM119 (CC105 recR) showing few papillae; 6, E. coli AM120 (CC105mutA recR) showing that the high papillation characteristic of mutA cells is unaffected in recR cells; 7, E. coli AM118 (CC105mutA recO) showing that the high papillation characteristic of mutA cells is unaffected in recO cells; 8, E. coli AM116 (CC105mutA recF) showing that the high papillation characteristic of mutA cells is unaffected in recF cells.