Unknown,Transcriptomics,Genomics,Proteomics

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Multiple roles of RNase Y in Streptococcus pyogenes mRNA metabolism

ABSTRACT: Streptococcus pyogenes (Group A streptococcus, GAS) is an important human pathogen that causes a variety of infectious diseases and sequelae. Recent studies showed virulence factor expression was controlled at multiple levels, including the post-transcriptional regulation. In this study, we examined the global half-lives of S. pyogenes mRNAs and explored the role RNase Y played in mRNA metabolism with microarray analysis. key word: genetic modification Streptococcus pyogenes NZ131 wild-type cells and ?rny strains were grown in C-medium until late exponential phase. Rifampicin was added to the cell culture and samples were collected before and after rifampicin addition. The transcriptional profile of the whole genome before and after rifampicin addition was examined with microarray. Please note that mRNA decay assay resulted in considerable variations in the datasets. Samples were taken after rifampicin addition and subsequent incubation for different time intervals. During that time no new RNA is produced and the remaining RNA is degraded to various degrees.

ORGANISM(S): Streptococcus pyogenes

SUBMITTER: Jens Kreth

PROVIDER: E-GEOD-40198 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Streptococcus pyogenes is a major causative agent of tonsillitis or pharyngitis in children, which can lead to more invasive infections and noninfectious sequellae. S. pyogenes can persist in tonsils, while one-third of children treated with antibiotics continue to shed streptococci and have recurrent infections. Mouse nasal-associated lymphoid tissue (NALT) is functionally analogous to human oropharangeal lymphoid tissues. The innate immune responses of naÃ¯ve cells from a mucosal site to S. pyogenes is not well described; therefore, we infected C57BL/6 mice intranasally with 108 CFU S. pyogenes. Transcriptional responses by NALT after S. pyogenes infection were analyzed by Affymetrix microarray and quantitative RT-PCR. Wild-type S. pyogenes induces transcription of both type I and IFN-gamma-responsive genes, pro-inflammatory genes, and acute phase response plasma proteins within 24h after infection. Invasion of NALT and the induction of the interferon response were not dependent on expression of anti-phagocytic M1 protein. However, infection with an attenuated, less invasive mutant indicated that a robust innate response by NALT is significantly influenced by intra-NALT bacterial load. Granulocytic populations of NALT, cervical lymph nodes and spleen were discriminated by characteristic surface and intracellular markers. Intranasal infection induces systemic release of neutrophils and a substantial influx of neutrophils into NALT at 24h, which decline by 48h after infection. Macrophages do not significantly increase in S. pyogenes-infected NALT. Intranasal infection of IFN-gamma -/- (GKO) C57BL/6 mice did not lead to systemic dissemination of wild type S. pyogenes, despite reduced expression of IFN-gamma-responsive mRNAs in NALT. Infected GKO mice had an unregulated influx of neutrophils into NALT compared to immunocompetant mice and mice treated with an anti-IFN-gamma antibody more rapidly cleared S. pyogenes from NALT. Thus, IFN-gamma-induced responses have a suppressive influence on early clearance of this pathogen from NALT. Experiment Overall Design: C57BL/6 mice (6-10 weeks old), 4 per group, were infected intranasally with log-phase Streptococcus pyogenes, 2 to 4 x 10^8 CFU per 15 Âµl of pyrogen-free PBS. Sham-infected mice were administered 15 Âµl of the same PBS. Mice were infected with wild type strain 90-226 (Cue 1998), a 90-226 strain containing an in-frame deletion of M1 protein (90-226 delta emm1) (Zimmerlein 2005) or an attenuated 90-226 which lacks both M1 and SCPA proteins (90-226att). NALT was collected from mice at 24h after infection and stored in RNAlater until RNA could be purified).