Transcriptional Profiling and Molecular Characterization of the yccT Mutant Link: A Novel STY1099 Protein with the Peroxide Stress Response and Cell Division of Salmonella enterica Serovar Enteritidis.

Vidovic Vidovic,Johny Johny,Mendoza Mendoza,Reed Reed,Abrahante Abrahante,An An,Liu Liu

doi:10.3390/biology8040086

Abstract

Uncharacterized protein STY1099, encoded by the yccT gene, was previously identified as the most altered (i.e., upregulated) protein among the ZnO nanoparticle (NP) stimulon of Salmonella enterica serovar Enteritidis. Here we combined various stress response-related assays with functional genetics, global transcriptomic and proteomic analyses to characterize the yccT gene and its STY1099 product. Exposure of S. enterica Enteritidis to H2O2 (i.e., hydrogen peroxide) resulted in a significant (p < 0.0001) upregulation of the yccT gene, whereas exposure to paraquat (i.e., superoxide) did not alter the expression of the yccT gene. The ∆yccT mutant of S. enterica Enteritidis exposed to 0.75 mM H2O2, showed significantly reduced (p < 0.05) viability compared to the wild type strain. Further, comparative transcriptome analyses supported by Co-immunoprecipitation (Co-IP) assay revealed that STY1099 protein plays a role in redox homeostasis during the peroxide stress assault via involvement in the processes of respiratory nitrate reductase, oxidoreductase activities, cellular uptake and stress response. In addition, we found that the STY1099 protein has the monopolar subcellular location and that it interacts with key cell division proteins, MinD, and FtsH, as well as with a rod shape-determining protein MerB.

Highlights

Non-typhoidal Salmonella (NTS) are zoonotic pathogens of global health importance [1]
After demonstrating yccT induction by peroxide, we investigated whether yccT plays a role in hydrogen peroxide tolerance of S. enterica Enteritidis
We demonstrated that under peroxide stress an S. enterica Enteritidis strain lacking yccT showed a significant decrease in viability, compared to that of the wild type, indicating that the STY1099 protein likely plays a role in protecting S. enterica Enteritidis from the peroxide stress assault

Summary

Introduction

Non-typhoidal Salmonella (NTS) are zoonotic pathogens of global health importance [1]. The lifestyle of NTS includes frequent multi-host transmission events and short- or relatively long-term survival in the external environment outside animal hosts [2]. To respond to these changing conditions, NTS has acquired a variety of adaptive stress response mechanisms that ensure long-term survival of the pathogen in harsh environments [3,4]. Response to oxidative stress is considered a critical adaptive mechanism for NTS, both within the host [5] and outside the primary habitat of this pathogen [6]. Salmonella enterica possesses two distinct oxidative stress-response systems: (i) a peroxide stress-response system and (ii) a superoxide stress-response system [7].

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