Genome‐wide screening of potentialRNase Y‐processedmRNAs in the M49 serotypeStreptococcus pyogenesNZ131

Abstract RN ase Y is a major endoribonuclease in Group A streptococcus ( GAS ) and other Gram‐positive bacteria. Our previous study showed that RN ase Y was involved in mRNA degradation and processing in GAS . We hypothesized that mRNA processing regulated the expression of important GAS virulence factors via altering their mRNA stabilities and that RN ase Y mediated at least some of the mRNA ‐processing events. The aims of this study were to (1) identify mRNA s that were processed by RN ase Y and (2) confirm the mRNA ‐processing events. The transcriptomes of Streptococcus pyogenes NZ 131 wild type and its RN ase Y mutant ( Δrny ) were examined with RNA ‐seq. The data were further analyzed to define GAS operons. The mRNA stabilities of the wild type and Δrny at subgene level were determined with tiling array analysis. Operons displaying segmental stability in the wild type but not in the Δrny were predicted to be RN ase Y processed. Overall 865 operons were defined and their boundaries predicted. Further analysis narrowed down 15 mRNA s potentially processed by RN ase Y. A selection of four candidates including folC1 (folylpolyglutamate synthetase), prtF (fibronectin‐binding protein), speG (streptococcal exotoxin G), ropB (transcriptional regulator of speB ), and ypaA (riboflavin transporter) mRNA s was examined with Northern blot analysis. However, only folC1 was confirmed to be processed, but it is unlikely that RN ase Y is responsible. We conclude that GAS use RN ase Y to selectively process mRNA , but the overall impact is confined to selected virulence factors.