Fig 4. Both induction of spx and Spx stabilization are required for full and timely induction of Spx-controlled genes in response to cell wall stress.
Activation of Spx by cell wall and disulfide stress takes place through independent pathways. The expression dynamics of the genes (A) trxA and (B) trxB were monitored in WT, PM1*, ΔyirB, and the double mutant PM1* ΔyirB. Cells were treated with vancomycin or diamide (N = 4). (C) Spx levels in WT, PM1*, and PM1* ΔyirB after treatment with vancomycin revealed additivity between transcriptional induction of spx and Spx stabilization (N = 4), as determined using western blot. D) Expression profile of selected genes using RT-qPCR (N = 3). The mRNA levels were normalized against the 23S rRNA. Error bars represent SEM.