FIG 6.

The tha operon is regulated by the stringent response. (A) Monitoring by RT-qPCR of the relative expression (log₂) of the rv0634A, rpmG2, hadABC, rel_Mtb, mprA, and sigE genes in the WT strain (WT/pGBT) upon 6 and 24 h of starvation. The values are expressed as a ratio to WT values in unstarved log-phase cultures. (B) Genetic map showing the rel_Mtb and sh ble allelic exchange. Primers for the deletion analysis by PCR are symbolized by arrows. (C and D) PCR products obtained with the a+b and a+c primer pairs to confirm the deletion of the rel_Mtb gene. Lysates of the WT strain (lanes 1) and of a Δrel_Mtb clone (lanes 2) were used as PCR templates. (E) Gene expression ratio relative to values for the WT/pGBT strain from log phase, upon 6 and 24 h of starvation, respectively. In panels A and E, error bars represent SEM from three biological triplicates. P values were <0.05 (*), <0.01 (**), <0.001 (***), and < 0.0001 (****).