GSE103364 Streptococcus pneumoniae TIGR4 phase-locked opacity variants differ in virulence phenotypes

Contributors : Melissa B Oliver ; Ankita Basu Roy ; W E SwordsSeries Type : Expression profiling by high throughput sequencingOrganism : Streptococcus pneumoniaeStreptococcus pneumoniae (pneumococcus) is a leading human pathogen that can cause serious localized and invasive diseases. Pneumococci can undergo a spontaneous and reversible phase variation that is reflected in colony opacity, which allows the population to adapt to different host environments. Generally, transparent variants are adapted for nasopharyngeal colonization whereas opaque variants are associated with invasive disease. In recent work, colony phase variation was shown to occur by means of recombination events to generate multiple alleles of the hsdS targeting domain of a DNA methylase complex, which mediates epigenetic changes in gene expression. A panel of isogenic strains were created in the well-studied S. pneumoniae TIGR4 background that are “locked” in the transparent (n=4) or opaque (n=2) colony phenotype. The strains had significant differences in colony size which were stable over multiple passages in vitro and in vivo. While there were no significant differences in adherence for the phase-locked mutant strains to immortalized e pithelial cells, biofilm formation and viability was reduced for opaque variants in static assays. Nasopharyngeal colonization was stable for all strains, but the mortality rate differed between them. Transcript profiling by RNA-seq analyses revealed that expression...
Source: GEO: Gene Expression Omnibus - Category: Genetics & Stem Cells Tags: Expression profiling by high throughput sequencing Streptococcus pneumoniae Source Type: research