title: Null Mutations of Group A Streptococcus Orphan Kinase RocA: Selection in Mouse Infection and Comparison with CovS Mutations in Alteration of In Vitro and In Vivo Protease SpeB Expression and Virulence.
abstract: Group A Streptococcus (GAS) acquires mutations of the virulence regulator CovRS in human and mouse infections, and these mutations result in the upregulation of virulence genes and the downregulation of the protease SpeB. To identify in vivo mutants with novel phenotypes, GAS isolates from infected mice were screened by enzymatic assays for SpeB and the platelet-activating factor acetylhydrolase Sse, and a new type of variant that had enhanced Sse expression and normal levels of SpeB production was identified (the variants had a phenotype referred to as enhanced Sse activity [SseA+] and normal SpeB activity [SpeBA+]). SseA+SpeBA+variants had transcript levels of CovRS-controlled virulence genes comparable to those of a covS mutant but had no covRS mutations. Genome resequencing of an SseA+SpeBA+isolate identified a C605A nonsense mutation in orphan kinase gene rocA, and 6 other SseA+SpeBA+isolates also had nonsense mutations or small indels in rocA RocA and CovS mutants had similar levels of enhancement of the expression of CovRS-controlled virulence genes at the exponential growth phase; however, mutations of RocA but not mutations of CovS did not result in the downregulation of speB transcription at stationary growth phase or in subcutaneous infection of mice. GAS with RocA and CovS mutations caused greater enhancement of the expression of hasA than spyCEP in mouse skin infection than wild-type GAS did. RocA mutants ranked between wild-type GAS and CovS mutants in skin invasion, inhibition of neutrophil recruitment, and virulence in subcutaneous infection of mice. Thus, GAS RocA mutants can be selected in subcutaneous infections in mice and exhibit gene expression patterns and virulences distinct from those of CovS mutants. The findings provide novel information for understanding GAS fitness mutations in vivo, virulence gene regulation, in vivo gene expression, and virulence.
authors: Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA.
authors: Wenchao
authors: W
authors: Feng
authors: Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA.
authors: Dylan
authors: D
authors: Minor
authors: Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA.
authors: Mengyao
authors: M
authors: Liu
authors: Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA.|College of Food Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China.
authors: Jinquan
authors: J
authors: Li
authors: Department of Animal & Range Sciences, Montana State University, Bozeman, Montana, USA.
authors: Suzanne L
authors: SL
authors: Ishaq
authors: Department of Animal & Range Sciences, Montana State University, Bozeman, Montana, USA.
authors: Carl
authors: C
authors: Yeoman
authors: Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA blei@montana.edu.
authors: Benfang
authors: B
authors: Lei
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D018389:Codon, Nonsense / Q000235:genetics*; D015536:Down-Regulation / Q000235:genetics; D005098:Exotoxins / Q000235:genetics*; D005260:Female; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics; D000071677:Histidine Kinase; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D020556:Neutrophil Infiltration / Q000235:genetics; D012867:Skin / Q000382:microbiology; D013290:Streptococcal Infections / Q000382:microbiology*; D013297:Streptococcus pyogenes / Q000235:genetics*; D015534:Trans-Activators / Q000235:genetics*; D014158:Transcription, Genetic / Q000235:genetics; D014774:Virulence / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D018389:Codon, Nonsense; D005098:Exotoxins; D047908:Intracellular Signaling Peptides and Proteins; C474644:RocA protein, Streptococcus pyogenes; D015534:Trans-Activators; C027951:erythrogenic toxin; C534547:CovS protein, Streptococcus pyogenes; D000071677:Histidine Kinase
keywords: CovRS; PAF acetylhydrolase; RocA; SpeB; Streptococcus pyogenes; group A Streptococcus; in vivo expression; mutation; virulence; virulence regulation