Dataset Information

Phenotypic characterization of the foldase homologue PrsA in Streptococcus mutans.

ABSTRACT: Streptococcus mutans is generally considered to be the principal etiological agent for dental caries. Many of the proteins necessary for its colonization of the oral cavity and pathogenesis are exported to the cell surface or the extracellular matrix, a process that requires the assistance of the export machineries. Bioinformatic analysis revealed that the S. mutans genome contains a prsA gene, whose counterparts in other gram-positive bacteria, including Bacillus and Lactococcus, encode functions involved in protein post-export. In this study, we constructed a PrsA-deficient derivative of S. mutans and demonstrated that the prsA mutant displayed an altered cell wall/membrane protein profile as well as cell-surface-related phenotypes, including auto-aggregation, increased surface hydrophobicity and abnormal biofilm formation. Further analysis revealed that the disruption of the prsA gene resulted in reduced insoluble glucan production by cell surface localized glucosyltransferases, and mutacin as well as cell surface-display of a heterologous expressed GFP fusion to the cell surface protein SpaP. Our study suggested that PrsA in S. mutans encodes functions similar to those identified in Bacillus, and so is likely to be involved in protein post-export.

SUBMITTER: Guo L

PROVIDER: S-EPMC3819222 | biostudies-literature | 2013 Apr

REPOSITORIES: biostudies-literature

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Phenotypic characterization of the foldase homologue PrsA in Streptococcus mutans.

Guo L L Wu T T Hu W W He X X Sharma S S Webster P P Gimzewski J K JK Zhou X X Lux R R Shi W W

Molecular oral microbiology 20121213 2

Streptococcus mutans is generally considered to be the principal etiological agent for dental caries. Many of the proteins necessary for its colonization of the oral cavity and pathogenesis are exported to the cell surface or the extracellular matrix, a process that requires the assistance of the export machineries. Bioinformatic analysis revealed that the S. mutans genome contains a prsA gene, whose counterparts in other gram-positive bacteria, including Bacillus and Lactococcus, encode functio ...[more]

PMID: 23241367

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Project description:In oral biofilms, two of the major environmental challenges encountered by the dental pathogen Streptococcus mutans are acid and oxidative stresses. Previously, we showed that the S. mutans transcriptional regulators SpxA1 and SpxA2 (formerly SpxA and SpxB, respectively) are involved in stress survival by activating the expression of classic oxidative stress genes such as dpr, nox, sodA and tpx. We reasoned that some of the uncharacterized genes under SpxA1/A2 control are potentially involved in oxidative stress management. Therefore, the goal of this study was to use Spx-regulated genes as a tool to identify novel oxidative stress genes in S. mutans. Quantitative real-time PCR was used to evaluate the responses of ten Spx-regulated genes during H2O2 stress in the parent and ?spx strains. Transcription activation of the H2O2-induced genes (8 out of 10) was strongly dependent on SpxA1 and, to a lesser extent, SpxA2. In vitro transcription assays revealed that one or both Spx proteins directly regulate three of these genes. The gene encoding the FeoB ferrous permease was slightly repressed by H2O2 but constitutively induced in strains lacking SpxA1. Nine genes were selected for downstream mutational analysis but inactivation of smu127, encoding a subunit of the acetoin dehydrogenase was apparently lethal. In vitro and in vivo characterization of the viable mutants indicated that, in addition to the transcriptional activation of reducing and antioxidant pathways, Spx performs an important role in iron homeostasis by regulating the intracellular availability of free iron. In particular, inactivation of the genes encoding the Fe-S biogenesis SUF system and the previously characterized iron-binding protein Dpr resulted in impaired growth under different oxidative stress conditions, increased sensitivity to iron and lower infectivity in rats. These results serve as an entryway into the characterization of novel genes and pathways that allow S. mutans to cope with oxidative stress.

Dataset Information

Phenotypic characterization of the foldase homologue PrsA in Streptococcus mutans.

Publications

Phenotypic characterization of the foldase homologue PrsA in Streptococcus mutans.

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