The Two-Component Sensor Protein CovS Affects Penicilling Susceptibility by Modulation of Cell-Wall Synthesis in Streptococcus pyogenes

Masaaki Minami,Syun Syun Torii,Michio Ohta

doi:10.4236/jbm.2015.33008

Masaaki Minami, Syun Syun Torii + Show 1 more

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https://doi.org/10.4236/jbm.2015.33008

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Abstract

In Streptococcus pyogenes, we have described the two-component signal transduction sensor and regulatory systems, CovR/S affect the antimicrobial susceptibility including penicillin G before. But the mechanism how two-component sensor protein CovS modulates penicillin G susceptibility has not been elucidated till date. This study aimed to determine how the CovS affected penicillin G susceptibility in Streptococcus pyogenes by northern blot analysis. At first, we investigated the covS mRNA expression under penicillin G induction. We found that the decrease of covS mRNA expression under Penicillin G stimulation. Next we investigated the expression of cell wall synthesis gene, pbp2a and glmM with use of covS knockout mutants from emm1 Streptococcus pyogenes strain 1529. We found that the cell-wall synthesis gene expression of the ?covS mutant strain were lower than that of the wild-type strain. Furthermore the expression of glmM mRNA gene was lower than the expression of pbp2a mRNA gene in the ?covS mutant strain. The covS-complemented strain almost restored the mRNA expression compared to covS mutant strain. The two-component sensor protein CovS affects the susceptibility to penicillin G in Streptococcus pyogenes by modulation of cell-wall synthesis.

Highlights

Streptococcus pyogenes is a gram-positive bacterium that infects the upper respiratory tract, including the tonsils and pharynx, and is responsible for post-infectious diseases, such as rheumatic fever, glomerulonephritis, and streptococcal toxic shock-like syndrome [1]
We evaluated the expression of glmM mRNAs among Streptococcus pyogenes 1529 ∆covS mutant strains
We clarified that the mechanism between the Streptococcus pyogenes two component sensor protein CovS and penicillin G susceptibility

Summary

Introduction

Streptococcus pyogenes is a gram-positive bacterium that infects the upper respiratory tract, including the tonsils and pharynx, and is responsible for post-infectious diseases, such as rheumatic fever, glomerulonephritis, and streptococcal toxic shock-like syndrome [1]. (2015) The Two-Component Sensor Protein CovS Affects Penicilling Susceptibility by Modulation of Cell-Wall Synthesis in Streptococcus pyogenes. In the basic model of two-component systems, interaction of an appropriate extracellular stimulus with the sensor histidine kinase alters the phosphorylation state of its cytoplasmic domain [2]. The prototypic sensor protein has kinase and/or phosphatase activity for a cognate regulator protein; phosphorylation (or dephosphorylation) of the regulator controls its activity as a transcriptional activator or repressor for one or more target genes [3]. Two-component systems CovR/S in Streptococcus pyognes has been shown to regulate expression of several virulence determinants, including the hyaluronic acid capsule, streptolysin S, and streptokinase [2] [3]. Microarray transcriptional profiling studies suggest that CovR/S regulates expression, directly or indirectly, of 15% of Streptococcus pyogenes genes [2] [3]

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