Figure 1.

The ssDNA exonucleases RecJ and ExoVII limit natural transformation in Vibrio cholerae. Natural transformation assays of the indicated V. cholerae strains with a polymerase chain reaction (PCR) product as tDNA that has (A) 3 kb arms of homology on each side of an antibiotic resistance marker (i.e. 3/3 kb) or (B) a product where one arm of homology is reduced to just 80 bp (i.e. 0.08/3 kb). Data are from at least three independent biological replicates and shown as the mean ± SD. Statistical comparisons were made by Student's t-test to the wild-type (WT) strain. *P < 0.05, **P < 0.01 and ***P < 0.001.