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Spencer BL, Job AM, Robertson CM, Hameed ZA, Serchejian C, Wiafe-Kwakye CS, Mendonça JC, Apolonio MA, Nagao PE, Neely MN, Korotkova N, Korotkov KV, Patras KA, Doran KS. Heterogeneity of the group B streptococcal type VII secretion system and influence on colonization of the female genital tract. Mol Microbiol 2023; 120:258-275. [PMID: 37357823 PMCID: PMC10527989 DOI: 10.1111/mmi.15115] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 06/06/2023] [Accepted: 06/08/2023] [Indexed: 06/27/2023]
Abstract
Type VIIb secretion systems (T7SSb) in Gram-positive bacteria facilitate physiology, interbacterial competition, and/or virulence via EssC ATPase-driven secretion of small ɑ-helical proteins and toxins. Recently, we characterized T7SSb in group B Streptococcus (GBS), a leading cause of infection in newborns and immunocompromised adults. GBS T7SS comprises four subtypes based on variation in the C-terminus of EssC and the repertoire of downstream effectors; however, the intraspecies diversity of GBS T7SS and impact on GBS-host interactions remains unknown. Bioinformatic analysis indicates that GBS T7SS loci encode subtype-specific putative effectors, which have low interspecies and inter-subtype homology but contain similar domains/motifs and therefore may serve similar functions. We further identify orphaned GBS WXG100 proteins. Functionally, we show that GBS T7SS subtype I and III strains secrete EsxA in vitro and that in subtype I strain CJB111, esxA1 appears to be differentially transcribed from the T7SS operon. Furthermore, we observe subtype-specific effects of GBS T7SS on host colonization, as CJB111 subtype I but not CNCTC 10/84 subtype III T7SS promotes GBS vaginal colonization. Finally, we observe that T7SS subtypes I and II are the predominant subtypes in clinical GBS isolates. This study highlights the potential impact of T7SS heterogeneity on host-GBS interactions.
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Affiliation(s)
- Brady L. Spencer
- University of Colorado-Anschutz, Department of Immunology and Microbiology, Aurora, CO, USA
| | - Alyx M. Job
- University of Colorado-Anschutz, Department of Immunology and Microbiology, Aurora, CO, USA
| | - Clare M. Robertson
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Zainab A. Hameed
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Camille Serchejian
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | | | - Jéssica C. Mendonça
- University of Colorado-Anschutz, Department of Immunology and Microbiology, Aurora, CO, USA
- Rio de Janeiro State University, Roberto Alcântara Gomes Biology Institute, Rio de Janeiro, RJ, Brazil
| | - Morgan A. Apolonio
- University of Colorado-Anschutz, Department of Immunology and Microbiology, Aurora, CO, USA
- National Summer Undergraduate Research Program, University of Arizona, Tucson, AZ, USA
| | - Prescilla E. Nagao
- Rio de Janeiro State University, Roberto Alcântara Gomes Biology Institute, Rio de Janeiro, RJ, Brazil
| | - Melody N. Neely
- University of Maine, Molecular & Biomedical Sciences, Orono, ME, USA
| | - Natalia Korotkova
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, KY, USA
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | - Konstantin V. Korotkov
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | - Kathryn A. Patras
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
- Alkek Center for Metagenomics and Microbiome Research, Baylor College of Medicine, Houston, TX, USA
| | - Kelly S. Doran
- University of Colorado-Anschutz, Department of Immunology and Microbiology, Aurora, CO, USA
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Spencer BL, Job AM, Robertson CM, Hameed ZA, Serchejian C, Wiafe-Kwakye CS, Mendonça JC, Apolonio MA, Nagao PE, Neely MN, Korotkova N, Korotkov KV, Patras KA, Doran KS. Heterogeneity of the group B streptococcal type VII secretion system and influence on colonization of the female genital tract. bioRxiv 2023:2023.01.25.525443. [PMID: 36747681 PMCID: PMC9900821 DOI: 10.1101/2023.01.25.525443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Type VIIb secretion systems (T7SSb) in Gram-positive bacteria facilitate physiology, interbacterial competition, and/or virulence via EssC ATPase-driven secretion of small ɑ-helical proteins and toxins. Recently, we characterized T7SSb in group B Streptococcus (GBS), a leading cause of infection in newborns and immunocompromised adults. GBS T7SS comprises four subtypes based on variation in the C-terminus of EssC and the repertoire of downstream effectors; however, the intra-species diversity of GBS T7SS and impact on GBS-host interactions remains unknown. Bioinformatic analysis indicates that GBS T7SS loci encode subtype-specific putative effectors, which have low inter-species and inter-subtype homology but contain similar domains/motifs and therefore may serve similar functions. We further identify orphaned GBS WXG100 proteins. Functionally, we show that GBS T7SS subtype I and III strains secrete EsxA in vitro and that in subtype I strain CJB111, esxA1 appears to be differentially transcribed from the T7SS operon. Further, we observe subtype-specific effects of GBS T7SS on host colonization, as subtype I but not subtype III T7SS promotes GBS vaginal persistence. Finally, we observe that T7SS subtypes I and II are the predominant subtypes in clinical GBS isolates. This study highlights the potential impact of T7SS heterogeneity on host-GBS interactions.
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Affiliation(s)
- Brady L. Spencer
- University of Colorado-Anschutz, Department of Immunology and Microbiology, Aurora, CO, USA
| | - Alyx M. Job
- University of Colorado-Anschutz, Department of Immunology and Microbiology, Aurora, CO, USA
| | - Clare M. Robertson
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Zainab A. Hameed
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Camille Serchejian
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | | | - Jéssica C. Mendonça
- University of Colorado-Anschutz, Department of Immunology and Microbiology, Aurora, CO, USA
- Rio de Janeiro State University, Roberto Alcantara Gomes Biology Institute, Rio de Janeiro, RJ, Brazil
| | - Morgan A. Apolonio
- University of Colorado-Anschutz, Department of Immunology and Microbiology, Aurora, CO, USA
- National Summer Undergraduate Research Program, University of Arizona, Tucson, AZ, USA
| | - Prescilla E. Nagao
- Rio de Janeiro State University, Roberto Alcantara Gomes Biology Institute, Rio de Janeiro, RJ, Brazil
| | - Melody N. Neely
- University of Maine, Molecular & Biomedical Sciences, Orono, ME, USA
| | - Natalia Korotkova
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, KY, USA
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | - Konstantin V. Korotkov
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | - Kathryn A. Patras
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
- Alkek Center for Metagenomics and Microbiome Research, Baylor College of Medicine, Houston, TX, USA
| | - Kelly S. Doran
- University of Colorado-Anschutz, Department of Immunology and Microbiology, Aurora, CO, USA
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