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Lautenschläger N, Schmidt K, Schiffer C, Wulff TF, Hahnke K, Finstermeier K, Mansour M, Elsholz AKW, Charpentier E. Expanding the genetic toolbox for the obligate human pathogen Streptococcus pyogenes. Front Bioeng Biotechnol 2024; 12:1395659. [PMID: 38911550 PMCID: PMC11190166 DOI: 10.3389/fbioe.2024.1395659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Accepted: 05/06/2024] [Indexed: 06/25/2024] Open
Abstract
Genetic tools form the basis for the study of molecular mechanisms. Despite many recent advances in the field of genetic engineering in bacteria, genetic toolsets remain scarce for non-model organisms, such as the obligatory human pathogen Streptococcus pyogenes. To overcome this limitation and enable the straightforward investigation of gene functions in S. pyogenes, we have developed a comprehensive genetic toolset. By adapting and combining different tools previously applied in other Gram-positive bacteria, we have created new replicative and integrative plasmids for gene expression and genetic manipulation, constitutive and inducible promoters as well as fluorescence reporters for S. pyogenes. The new replicative plasmids feature low- and high-copy replicons combined with different resistance cassettes and a standardized multiple cloning site for rapid cloning procedures. We designed site-specific integrative plasmids and verified their integration by nanopore sequencing. To minimize the effect of plasmid integration on bacterial physiology, we screened publicly available RNA-sequencing datasets for transcriptionally silent sites. We validated this approach by designing the integrative plasmid pSpy0K6 targeting the transcriptionally silent gene SPy_1078. Analysis of the activity of different constitutive promoters indicated a wide variety of strengths, with the lactococcal promoter P 23 showing the strongest activity and the synthetic promoter P xylS2 showing the weakest activity. Further, we assessed the functionality of three inducible regulatory elements including a zinc- and an IPTG-inducible promoter as well as an erythromycin-inducible riboswitch that showed low-to-no background expression and high inducibility. Additionally, we demonstrated the applicability of two codon-optimized fluorescent proteins, mNeongreen and mKate2, as reporters in S. pyogenes. We therefore adapted the chemically defined medium called RPMI4Spy that showed reduced autofluorescence and enabled efficient signal detection in plate reader assays and fluorescence microscopy. Finally, we developed a plasmid-based system for genome engineering in S. pyogenes featuring the counterselection marker pheS*, which enabled the scarless deletion of the sagB gene. This new toolbox simplifies previously laborious genetic manipulation procedures and lays the foundation for new methodologies to study gene functions in S. pyogenes, leading to a better understanding of its virulence mechanisms and physiology.
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Affiliation(s)
| | - Katja Schmidt
- Max Planck Unit for the Science of Pathogens, Berlin, Germany
| | | | - Thomas F. Wulff
- Max Planck Unit for the Science of Pathogens, Berlin, Germany
| | - Karin Hahnke
- Max Planck Unit for the Science of Pathogens, Berlin, Germany
| | | | - Moïse Mansour
- Max Planck Unit for the Science of Pathogens, Berlin, Germany
| | | | - Emmanuelle Charpentier
- Max Planck Unit for the Science of Pathogens, Berlin, Germany
- Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
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Ravins M, Ambalavanan P, Biswas D, Tan RYM, Lim KXZ, Kaufman Y, Anand A, Sharma A, Hanski E. Murine Soft Tissue Infection Model to Study Group A Streptococcus (GAS) Pathogenesis in Necrotizing Fasciitis. Methods Mol Biol 2022; 2427:185-200. [PMID: 35619035 DOI: 10.1007/978-1-0716-1971-1_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Group A streptococcus (GAS) necrotizing fasciitis (NF) causes high morbidity and mortality despite prompt intravenous administration of antibiotics, surgical soft-tissue debridement, and supportive treatment in the intensive care unit. Since there is no effective vaccine against GAS infections, a comprehensive understanding of NF pathogenesis is required to design more efficient treatments. To increase our understanding of NF pathogenesis, we need a reliable animal model that mirrors, at least in part, the infectious process in humans. This chapter describes a reliable murine model of human NF that mimics the histopathology observed in humans, namely the destruction of soft tissue, a paucity of infiltrating neutrophils, and the presence of many gram-positive cocci at the center of the infection.
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Affiliation(s)
- Miriam Ravins
- Department of Microbiology and Molecular Genetics, The Institute for Medical Research, Israel-Canada (IMRIC), Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Poornima Ambalavanan
- Singapore-HUJ Alliance for Research and Enterprise, MMID Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), Singapore, Singapore
- Department of Microbiology and Immunology, National University of Singapore, Singapore, Singapore
| | - Debabrata Biswas
- Singapore-HUJ Alliance for Research and Enterprise, MMID Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), Singapore, Singapore
- Department of Microbiology and Immunology, National University of Singapore, Singapore, Singapore
| | - Rachel Ying Min Tan
- Singapore-HUJ Alliance for Research and Enterprise, MMID Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), Singapore, Singapore
- Department of Microbiology and Immunology, National University of Singapore, Singapore, Singapore
| | - Kimberly Xuan Zhen Lim
- Singapore-HUJ Alliance for Research and Enterprise, MMID Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), Singapore, Singapore
- Department of Microbiology and Immunology, National University of Singapore, Singapore, Singapore
| | - Yael Kaufman
- Department of Microbiology and Molecular Genetics, The Institute for Medical Research, Israel-Canada (IMRIC), Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Aparna Anand
- Department of Microbiology and Molecular Genetics, The Institute for Medical Research, Israel-Canada (IMRIC), Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Abhinay Sharma
- Department of Microbiology and Molecular Genetics, The Institute for Medical Research, Israel-Canada (IMRIC), Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Emanuel Hanski
- Department of Microbiology and Molecular Genetics, The Institute for Medical Research, Israel-Canada (IMRIC), Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.
- Singapore-HUJ Alliance for Research and Enterprise, MMID Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), Singapore, Singapore.
- Department of Microbiology and Immunology, National University of Singapore, Singapore, Singapore.
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