Supporting Figure 6
Fig. 6. All four snm mutants were identified by signature-tagged mutagenesis (STM). Signature tags from mutant mycobacteria harvested from the inoculum (input) and the lungs of two mice after 3 wk of growth were amplified, radiolabeled, and hybridized to tag array filters. Tags from underrepresented mutants are shown next to control spots. To carry out the STM screen, pools of 48 randomly generated transposon mutants were created such that each mutant could be distinguished by the presence of a unique DNA sequence tag. The representation of individual mutants within each pool was quantified by amplification of all of the tags by PCR, followed by labeling and hybridizing to filter arrays spotted with each individual tag. By comparing the representation of each mutant in the pool before infection and after 3 wk of growth in the lungs of mice, we were able to identify mutants that were attenuated for growth during early stages of infection.
