Dual promoters of the major catalase (KatA) govern distinct survival strategies of Pseudomonas aeruginosa.

In-Young Chung,Hye-Jeong Jang,You-Hee Cho,Bi-O Kim

doi:10.1038/srep31185

Abstract

KatA is the major catalase required for hydrogen peroxide (H2O2) resistance and acute virulence in Pseudomonas aeruginosa PA14, whose transcription is driven from the promoter (katAp1) located at 155 nucleotide (nt) upstream of the start codon. Here, we identified another promoter (katAp2), the +1 of which was mapped at the 51 nt upstream of the start codon, which was responsible for the basal transcription during the planktonic culture and down-regulated upon H2O2 treatment under the control by the master regulator of anaerobiosis, Anr. To dissect the roles of the dual promoters in conditions involving KatA, we created the promoter mutants for each -10 box (p1m, p2m, and p1p2m) and found that katAp1 is required for the function of KatA in the logarithmic growth phase during the planktonic culture as well as in acute virulence, whereas katAp2 is required for the function of KatA in the stationary phase as well as in the prolonged biofilm culture. This dismantling of the dual promoters of katA sheds light on the roles of KatA in stress resistance in both proliferative and growth-restrictive conditions and thus provides an insight into the regulatory impacts of the major catalase on the survival strategies of P. aeruginosa.

Highlights

We have explored the regulatory module underlying the anaerobic regulation of KatA, by newly identifying a second promoter of the katA gene, which is responsible for the basal expression of KatA during the planktonic growth of P. aeruginosa strain PA14
Despite over 5-fold induction of katAp1 transcription upon H2O2 exposure, the katA-lacZ fusion displayed a minor (~2-fold) induction[8], which may be attributed to another level of regulation. We have identified another promoter of the katA gene, katAp2: from the high-resolution S1 nuclease mapping data, a second protective band was observed at the 51 nt upstream (T-51) of the translation initiation codon (Fig. 1A)
KatA is the major catalase of P. aeruginosa, whose “adaptive” function is to dismutate H2O2, an ROS either sporadically generated during the normal respiration on O2 or externally provided by redox-cycling agents or host factors

Summary

Introduction

We have explored the regulatory module underlying the anaerobic regulation of KatA, by newly identifying a second promoter (katAp2) of the katA gene, which is responsible for the basal expression of KatA during the planktonic growth of P. aeruginosa strain PA14. This second promoter is regulated primarily by Anr. More importantly, the mutation analyses of each promoter revealed the separate roles of the dual promoters to cope with reactive oxygen and/or nitrogen species (ROS and RNS), which is dependent on the growth states

Methods

Results

Conclusion