Creation of M. smegmatis
ohr and ohrR mutant strains. MSWt, MSΔohr, MSΔohrR, and MSΔohr-ohrR are the wild-type strain and the ohr mutant, ohrR mutant, and ohr-ohrR mutant of M. smegmatis, respectively. (A) Schematic representing the organization of the ohrR and ohr genes in the genomes of the M. smegmatis strains. Arrows, genes and their orientations; numbers within and below the arrows, the number assigned to each gene; StuI and NcoI, restriction sites in the region; Hygromycin, the location of the antibiotic resistance marker gene in MSΔohr, MSΔohrR, and MSΔohr-ohrR. (B) Southern analysis of genomic DNA. Chromosomal DNA from the M. smegmatis strains digested with StuI was probed with a radioactively labeled DNA (2,053 bp) encompassing the ohr and ohrR regions of M. smegmatis. The sizes of the signals are marked on the right.