Quorum-Sensing Regulator OpaR Directly Represses Seven Protease Genes in Vibrio parahaemolyticus

Abstract

Proteases play a key role in numerous bacterial physiological events. Microbial proteases are used in the pharmaceutical industry and in biomedical applications. The genus Vibrio comprises protease-producing bacteria. Proteases transform polypeptides into shorter chains for easier utilization. They also function as a virulence factor in pathogens. The mechanism by which protease genes are regulated in Vibrio parahaemolyticus, an emerging worldwide human pathogen, however, still remains unclear. Quorum sensing is the communication system of bacteria. OpaR is the master quorumsensing regulator in V. parahaemolyticus. In the present study, quantitative reverse transcriptase-polymerase chain reaction and protease gene promoter-fusion reporter assays revealed that OpaR represses seven protease genes-three metalloprotease genes and four serine protease genes-which are involved in environmental survival and bacterial virulence. Furthermore, the electrophoresis mobility shift assay demonstrated that OpaR is bound directly to the promoter region of each of the seven protease genes. DNase I footprinting identified the sequence of these OpaR-binding sites. ChIPseq analyses revealed 435 and 835 OpaR-binding sites in the late-log and stationary phases, respectively. These OpaR-binding sequences indicated a conserved OpaRbinding motif: TATTGATAAAATTATCAATA. These results advance our understanding of the protease regulation system in V. parahaemolyticus. This study is the first to reveal the OpaR motif within V. parahaemolyticus in vivo, using ChIP-seq, and to provide a database for OpaR direct regulon.

Detection of Quorum Sensing System (Cell to Cell Communication) Using Marker Strains in Vibrio alginolyticus Strains and Determine Virulence under Master of this System

“…Similar to results of these researchers our findings showed that V. alginolyticus produced biofilm, pigment, elastase and amylase under the management QS. QS induced gene expression of Asp, protease from V. alginolyticus (Chang and Lee, 2020).Unlike the findings in study of Chang and Lee 2020, it was determined that V. alginolyticus no produce protease in our study.…”

Computationally Designed Anti-LuxP DNA Aptamer Suppressed Flagellar Assembly- and Quorum Sensing-Related Gene Expression in Vibrio parahaemolyticus

“…The gene expression level of the QS master regulator at a high cell density, OpaR, was found to be significantly downregulated in the furanone treatment ( Figure 7 ), but the suppression was not significant in the aptamer treatments. The role of OpaR in regulating QS has been frequently reported [ 73 , 74 , 75 ]. It is involved in biofilm formation, swarming, motility, and type-III and -VI secretion systems in V. parahaemolyticus [ 76 , 77 ].…”

OpaR exerts a dynamic control over c-di-GMP homeostasis andcpsAexpression inV. parahaemolyticusthrough its regulation of ScrC and the trigger phosphodiesterase TpdA

“…Experiments were performed twice independently with three biological replicates each time. We used the raw data of the GEO datasets with the accession number GSE122479 generated in a previous report (36). The analysis was performed by the bioinformatic facility "Unidad de Análisis Bioinformáticos" from the Center for Genomic Sciences (UNAM).…”

“…It is possible that the change in c-di-GMP levels in the ΔopaR mutant strain under this condition is transient, while the resulting change in cpsA expression is more stable. As will be discussed later, OpaR is likely a direct regulator of cpsA expression and other biofilm related genes (23,35,36).…”