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Cai X, Yang S, Peng Y, Tan K, Xu P, Wu Z, Kwan KY, Jian J. Regulation of PhoB on biofilm formation and hemolysin gene hlyA and ciaR of Streptococcus agalactiae. Vet Microbiol 2024; 289:109961. [PMID: 38147806 DOI: 10.1016/j.vetmic.2023.109961] [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] [Received: 06/17/2023] [Revised: 12/08/2023] [Accepted: 12/19/2023] [Indexed: 12/28/2023]
Abstract
PhoB is a response regulator protein that plays a key role in the PhoBR two-component signal transduction system. In this study, we used transcriptome and proteomics techniques to evaluate the detect the gene network regulated by PhoB of Streptococcus agalactiae. The results showed that expression of biofilm formation and virulence-related genes were changed after phoB deficiency. Crystal violet and CLSM assay confirmed that the deletion of the phoB increased the thickness of S. agalactiae biofilm. The results of lacZ reporter and the bacterial one-hybridization method showed that PhoB could directly bind to the promoter regions of hemolysin A and ciaR genes but not to the promoter regions of cylE and hemolysin III. Through the construction of an 18-base pair deoxyribose nucleic acid (DNA) random fragment library and the bacterial one-hybridization system, it was found that the conservative sequence of PhoB binding was TTGGAGAA(G/T). Our research has uncovered the virulence potential of the PhoBR two-component system of S. agalactiae. The findings of this study provide the theoretical foundation for in-depth research on the pathogenic mechanism of S. agalactiae.
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Affiliation(s)
- Xiaohui Cai
- Guangxi Key Laboratory of Beibu Gulf Marine Biodiversity Conservation, Ocean College, Beibu Gulf University, Qinzhou 535011, China
| | - Shaoyu Yang
- Guangxi Key Laboratory of Beibu Gulf Marine Biodiversity Conservation, Ocean College, Beibu Gulf University, Qinzhou 535011, China
| | - Yinhui Peng
- Guangxi Key Laboratory of Beibu Gulf Marine Biodiversity Conservation, Ocean College, Beibu Gulf University, Qinzhou 535011, China; College of Fishery, Guangdong Ocean University, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animal, Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524088, China
| | - Kianann Tan
- Guangxi Key Laboratory of Beibu Gulf Marine Biodiversity Conservation, Ocean College, Beibu Gulf University, Qinzhou 535011, China
| | - Peng Xu
- Guangxi Key Laboratory of Beibu Gulf Marine Biodiversity Conservation, Ocean College, Beibu Gulf University, Qinzhou 535011, China
| | - Zaohe Wu
- College of Fishery, Guangdong Ocean University, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animal, Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524088, China
| | - Kit Yue Kwan
- Guangxi Key Laboratory of Beibu Gulf Marine Biodiversity Conservation, Ocean College, Beibu Gulf University, Qinzhou 535011, China.
| | - Jichang Jian
- College of Fishery, Guangdong Ocean University, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animal, Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524088, China.
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Cao Q, Dong Y, Guo C, Ji S, Nie M, Liu G, Wan X, Lu C, Liu Y. luxS contributes to intramacrophage survival of Streptococcus agalactiae by positively affecting the expression of fruRKI operon. Vet Res 2023; 54:83. [PMID: 37759250 PMCID: PMC10536698 DOI: 10.1186/s13567-023-01210-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 08/25/2023] [Indexed: 09/29/2023] Open
Abstract
The LuxS quorum sensing system is a widespread system employed by many bacteria for cell-to-cell communication. The luxS gene has been demonstrated to play a crucial role in intramacrophage survival of piscine Streptococcus agalactiae, but the underlying mechanism remains largely unknown. In this study, transcriptome analysis, followed by the luxS gene deletion and subsequent functional studies, confirmed that impaired bacterial survival inside macrophages due to the inactivation of luxS was associated with reduced transcription of the fruRKI operon, encoding the fructose-specific phosphotransferase system. Further, luxS was determined not to enhance the transcription of fruRKI operon by binding its promoter, but to upregulate the expression of this operon via affecting the binding ability of catabolite control protein A (CcpA) to the catabolite responsive element (cre) in the promoter of fruRKI. Collectively, our study identifies a novel and previously unappreciated role for luxS in bacterial intracellular survival, which may give a more thorough understanding of the immune evasion mechanism in S. agalactiae.
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Affiliation(s)
- Qing Cao
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Yuhao Dong
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Changming Guo
- Jiangsu Agri-Animal Husbandry Vocational College, Taizhou, Jiangsu, China
| | - Shuting Ji
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Meng Nie
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Guangjin Liu
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Xihe Wan
- Institute of Oceanology and Marine Fisheries, Nantong, China
| | - Chengping Lu
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Yongjie Liu
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China.
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Gopalakrishna KP, Hillebrand GH, Bhavana VH, Elder JL, D'Mello A, Tettelin H, Hooven TA. Group B Streptococcus Cas9 variants provide insight into programmable gene repression and CRISPR-Cas transcriptional effects. Commun Biol 2023; 6:620. [PMID: 37296208 PMCID: PMC10256743 DOI: 10.1038/s42003-023-04994-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023] Open
Abstract
Group B Streptococcus (GBS; S. agalactiae) causes chorioamnionitis, neonatal sepsis, and can also cause disease in healthy or immunocompromised adults. GBS possesses a type II-A CRISPR-Cas9 system, which defends against foreign DNA within the bacterial cell. Several recent publications have shown that GBS Cas9 influences genome-wide transcription through a mechanism uncoupled from its function as a specific, RNA-programmable endonuclease. We examine GBS Cas9 effects on genome-wide transcription through generation of several isogenic variants with specific functional defects. We compare whole-genome RNA-seq from Δcas9 GBS with a full-length Cas9 gene deletion; dcas9 defective in its ability to cleave DNA but still able to bind to frequently occurring protospacer adjacent motifs; and scas9 that retains its catalytic domains but is unable to bind protospacer adjacent motifs. Comparing scas9 GBS to the other variants, we identify nonspecific protospacer adjacent motif binding as a driver of genome-wide, Cas9 transcriptional effects in GBS. We also show that Cas9 transcriptional effects from nonspecific scanning tend to influence genes involved in bacterial defense and nucleotide or carbohydrate transport and metabolism. While genome-wide transcription effects are detectable by analysis of next-generation sequencing, they do not result in virulence changes in a mouse model of sepsis. We also demonstrate that catalytically inactive dCas9 expressed from the GBS chromosome can be used with a straightforward, plasmid-based, single guide RNA expression system to suppress transcription of specific GBS genes without potentially confounding off-target effects. We anticipate that this system will be useful for study of nonessential and essential gene roles in GBS physiology and pathogenesis.
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Affiliation(s)
| | - Gideon H Hillebrand
- University of Pittsburgh School of Medicine, Program in Microbiology and Immunology, Pittsburgh, PA, USA
| | - Venkata H Bhavana
- University of Pittsburgh School of Medicine, Department of Pediatrics, Pittsburgh, PA, USA
| | - Jordan L Elder
- The Cleveland Clinic, Clinical Laboratory Services, Cleveland, OH, USA
| | - Adonis D'Mello
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Hervé Tettelin
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Thomas A Hooven
- University of Pittsburgh School of Medicine, Department of Pediatrics, Pittsburgh, PA, USA.
- Richard King Mellon Institute for Pediatric Research, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
- UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA.
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Gopalakrishna KP, Hillebrand GH, Bhavana VH, Elder JL, D'Mello A, Tettelin H, Hooven TA. Group B Streptococcus Cas9 variants provide insight into programmable gene repression and CRISPR-Cas transcriptional effects. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.24.542094. [PMID: 37292749 PMCID: PMC10245859 DOI: 10.1101/2023.05.24.542094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Group B Streptococcus (GBS; S. agalactiae ) causes chorioamnionitis, neonatal sepsis, and can also cause disease in healthy or immunocompromised adults. GBS possesses a type II-A CRISPR-Cas9 system, which defends against foreign DNA within the bacterial cell. Several recent publications have shown that GBS Cas9 influences genome-wide transcription through a mechanism uncoupled from its function as a specific, RNA-programmable endonuclease. We examine GBS Cas9 effects on genome-wide transcription through generation of several isogenic variants with specific functional defects. We compare whole-genome RNA-seq from Δ cas9 GBS with a full-length Cas9 gene deletion; dcas9 defective in its ability to cleave DNA but still able to bind to frequently occurring protospacer adjacent motifs; and scas9 that retains its catalytic domains but is unable to bind protospacer adjacent motifs. Comparing scas9 GBS to the other variants, we identify nonspecific protospacer adjacent motif binding as a driver of genome-wide, Cas9 transcriptional effects in GBS. We also show that Cas9 transcriptional effects from nonspecific scanning tend to influence genes involved in bacterial defense and nucleotide or carbohydrate transport and metabolism. While genome-wide transcription effects are detectable by analysis of next-generation sequencing, they do not result in virulence changes in a mouse model of sepsis. We also demonstrate that catalytically inactive dCas9 expressed from the GBS chromosome can be used with a straightforward, plasmid-based, single guide RNA expression system to suppress transcription of specific GBS genes without potentially confounding off-target effects. We anticipate that this system will be useful for study of nonessential and essential gene roles in GBS physiology and pathogenesis.
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