Regulatory Rewiring Confers Serotype-Specific Hyper-Virulence in the Human Pathogen Group A Streptococcus

We sequenced mRNA transcripts from three isogenic M3 serotype GAS strains, parental (MGAS10870), complement (10870::rocAM1), and deletion (10870?rocA). There were no significant changes between the parental and revertant strain. Comparison of the parental and complemented strain revealed several virulence factors were up-regulated in the parental strain where RocA function was diminished. We concluded that RocA, through direct or indirect mechanisms, is able to control numerous virulence genes and this lack of RocA regulation increases expression of virulence factors, which contributes to the hyper-virulent state of serotype M3 GAS. Overall design: GAS strains were grown to mid-exponential phase, total RNA isolated, rRNA depleted, cDNA libraries synthesized, and libraries analyzed using Illumina MiSeq and CLC Genomics Workbench version 7.5.1 RNA-seq software.