FIG. 1.

M. smegmatis possesses a highly homologous esxA/esxB genomic locus and secretes SmESAT-6 and SmCFP-10 in a medium-dependent manner. (A) The M. smegmatis genomic sequence (http://www.tigr.org/tdb/ufmg/) was obtained from The Institute for Genomic Research, and the M. tuberculosis genomic sequence was obtained from Tuberculist (http://genolist.pasteur.fr/TubercuList/). The numbers below each open reading frame from M. smegmatis denote the encoded protein's percent identity (using the lalign program [http://www.ch.embnet.org/software/LALIGN_form.html]) to its homologue in M. tuberculosis, and the gene names in boldface type represent those included in this study. The asterisks indicate that while the snm3 homologue from M. smegmatis is 51% identical to its counterpart in M. tuberculosis, it lacks the 577-bp N-terminal portion found in the M. tuberculosis gene. (B) Wild-type or ΔesxB cells were grown to late log phase in 7H9 or Sauton's medium, fractionated into the cell-associated pellet (P) fraction and the short-term culture filtrate (S) fraction, and analyzed by Western blotting for the indicated proteins.