Figure 4

Isoniazid susceptibility regulator predicted from the TFOE dataset. (A) KatG converts the prodrug isoniazid (INH) into its active form. One TF, Rv1909c, repressed katG when overexpressed, which should lead to reduced levels of KatG, less efficient conversion of INH, and a reduced effect of INH. (B) We confirmed this prediction by showing that, in the presence of twice the MIC of isoniazid (0.2 μg/mL), the furA TFOE strain was able to grow only when the TF was induced. This increased resistance to isoniazid was not seen in a control strain carrying the parent empty-vector plasmid.