Project description:We used RNA-Seq to assess how the presence/absence of the RD2 pathogenicity island influences global gene expression in the parental serotype M1 GAS isolate MGAS2221 and the parental serotype M49 isolate NZ131
Project description:Small non-coding RNAs (sRNAs) have attracted attention as a new class of gene regulators in eukaryotes and in bacteria. In this study, we identified novel sRNAs of the human pathogen Streptococcus pyogenes M49 (GAS M49). A temporal expression profile of potential sRNAs was determined for (GAS M49). Cells were grown in chemical defined medium (CDM), Todd-Hewitt broth (Invitrogen) supplemented with 0.5% yeast extract (THY) or Brain-Heart-Infusion (BHI) complex medium using tiling arrays representing the intergenic regions of the GAS M49 genome. We identified 55 putative sRNAs in GAS M49 that were expressed during growth. Of those, 35 sRNAs were novel, whereas 20 sRNAs were known. Already described sRNAs included molecules belonging to one of the common non-coding RNA families covered by the rfam collection and streptococcal sRNAs that have been detected in previous studies. Comparison to a recently published bioinformatics screen showed a low overlap between putative sRNA genes. This is in accordance with the results from other studies, which underlines the fact that a comprehensive analysis of sRNAs expressed by a given organism requires the complementary use of different methods and the investigation of several environmental conditions. Despite a high conservation of sRNA genes within streptococci, the expression of sRNAs is rather strain specific.
Project description:GAS is a highly virulent Gram-positive bacterium. For the successful infection GAS express many virulence factors, which are clustered together with transcriptional regulators in distinct genomic regions. Ralp3 is a central regulator of the ERES region. In this study, we investigated the role of Ralp3 in GAS pathogenesis. To characterize the Ralp3 regulatory function on the whole genome level, GAS M49 wild type and Äralp3 mutant strains were comprehensively compared by two colour microarray analysis. Samples were taken from cultures in the transition phase.
