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Kaimer C, Weltzer ML, Wall D. Two reasons to kill: predation and kin discrimination in myxobacteria. Microbiology (Reading) 2023; 169:001372. [PMID: 37494115 PMCID: PMC10433427 DOI: 10.1099/mic.0.001372] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Accepted: 07/15/2023] [Indexed: 07/27/2023]
Abstract
Myxobacteria are social microbial predators that use cell-cell contacts to identify bacterial or fungal prey and to differentiate kin relatives to initiate cellular responses. For prey killing, they assemble Tad-like and type III-like secretion systems at contact sites. For kin discrimination (KD), they assemble outer membrane exchange complexes composed of the TraA and TraB receptors at contacts sites. A type VI secretion system and Rhs proteins also mediate KD. Following cellular recognition, these systems deliver appropriate effectors into target cells. For prey, this leads to cell death and lysis for nutrient consumption by myxobacteria. In KD, a panel of effectors are delivered, and if adjacent cells are clonal cells, resistance ensues because they express a cognate panel of immunity factors; while nonkin lack complete immunity and are intoxicated. This review compares and contrasts recent findings from these systems in myxobacteria.
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Affiliation(s)
- Christine Kaimer
- Department of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Michael L. Weltzer
- Department of Molecular Biology, University of Wyoming, Laramie, WY, USA
| | - Daniel Wall
- Department of Molecular Biology, University of Wyoming, Laramie, WY, USA
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Lu W, Tan J, Lu H, Wang G, Dong W, Wang C, Li X, Tan C. Function of Rhs proteins in porcine extraintestinal pathogenic Escherichia coli PCN033. J Microbiol 2021; 59:854-860. [PMID: 34382147 DOI: 10.1007/s12275-021-1189-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 06/07/2021] [Accepted: 06/17/2021] [Indexed: 11/28/2022]
Abstract
Extraintestinal pathogenic Escherichia coli (ExPEC) is an important zoonotic pathogen that places severe burdens on public health and animal husbandry. There are many pathogenic factors in E. coli. The type VI secretion system (T6SS) is a nano-microbial weapon that can assemble quickly and inject toxic effectors into recipient cells when danger is encountered. T6SSs are encoded in the genomes of approximately 25% of sequenced Gram-negative bacteria. When these bacteria come into contact with eukaryotic cells or prokaryotic microbes, the T6SS assembles and secretes associated effectors. In the porcine ExPEC strain PCN033, we identified four classic rearrangement hotspot (Rhs) genes. We determined the functions of the four Rhs proteins through mutant construction and protein expression. Animal infection experiments showed that the Δrhs-1CT, Δrhs-2CT, Δrhs-3CT, and Δrhs-4CT caused a significant decrease in the multiplication ability of PCN033 in vivo. Cell infection experiments showed that the Rhs protein is involved in anti-phagocytosis activities and bacterial adhesion and invasion abilities. The results of this study demonstrated that rhs1, rhs3, and rh4 plays an important role in the interaction between PCN033 and host cell. Rhs2 has contribution to cell and mice infection. This study helps to elucidate the pathogenic mechanism governing PCN033 and may help to establish a foundation for further research seeking to identify potential T6SS effectors.
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Affiliation(s)
- Wenjia Lu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, P. R. China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430040, P. R. China
| | - Jia Tan
- Jiangxi Academy of Agricultural Science, Jiangxi, 333104, P.R. China
| | - Hao Lu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, P. R. China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430040, P. R. China
| | - Gaoyan Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, P. R. China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430040, P. R. China
| | - Wenqi Dong
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, P. R. China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430040, P. R. China
| | - Chenchen Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, P. R. China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430040, P. R. China
| | - Xiaodan Li
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, P. R. China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430040, P. R. China
| | - Chen Tan
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, P. R. China. .,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430040, P. R. China.
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Fawcett JA, Innan H. The role of gene conversion in preserving rearrangement hotspots in the human genome. Trends Genet 2013; 29:561-8. [PMID: 23953668 DOI: 10.1016/j.tig.2013.07.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 06/20/2013] [Accepted: 07/08/2013] [Indexed: 11/27/2022]
Abstract
Hotspots of non-allelic homologous recombination (NAHR) have a crucial role in creating genetic diversity and are also associated with dozens of genomic disorders. Recent studies suggest that many human NAHR hotspots have been preserved throughout the evolution of primates. NAHR hotspots are likely to remain active as long as the segmental duplications (SDs) promoting NAHR retain sufficient similarity. Here, we propose an evolutionary model of SDs that incorporates the effect of gene conversion and compare it with a null model that assumes SDs evolve independently without gene conversion. The gene conversion model predicts a much longer lifespan of NAHR hotspots compared with the null model. We show that the literature on copy number variants (CNVs) and genomic disorders, and also the results of additional analysis of CNVs, are all more consistent with the gene conversion model.
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Affiliation(s)
- Jeffrey A Fawcett
- Graduate University for Advanced Studies, Hayama, Kanagawa 240-0193, Japan
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