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Sahmi-Bounsiar D, Baudoin JP, Hannat S, Decloquement P, Chabrieres E, Aherfi S, La Scola B. Generation of Infectious Mimivirus Virions Through Inoculation of Viral DNA Within Acanthamoeba castellanii Shows Involvement of Five Proteins, Essentially Uncharacterized. Front Microbiol 2021; 12:677847. [PMID: 34305841 PMCID: PMC8299487 DOI: 10.3389/fmicb.2021.677847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 06/08/2021] [Indexed: 11/13/2022] Open
Abstract
One of the most curious findings associated with the discovery of Acanthamoeba polyphaga mimivirus (APMV) was the presence of many proteins and RNAs within the virion. Although some hypotheses on their role in Acanthamoeba infection have been put forward, none have been validated. In this study, we directly transfected mimivirus DNA with or without additional proteinase K treatment to extracted DNA into Acanthamoeba castellanii. In this way, it was possible to generate infectious APMV virions, but only without extra proteinase K treatment of extracted DNA. The virus genomes before and after transfection were identical. We searched for the remaining DNA-associated proteins that were digested by proteinase K and could visualize at least five putative proteins. Matrix-assisted laser desorption/ionization time-of-flight and liquid chromatography–mass spectrometry comparison with protein databases allowed the identification of four hypothetical proteins—L442, L724, L829, and R387—and putative GMC-type oxidoreductase R135. We believe that L442 plays a major role in this protein–DNA interaction. In the future, expression in vectors and then diffraction of X-rays by protein crystals could help reveal the exact structure of this protein and its precise role.
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Affiliation(s)
- Dehia Sahmi-Bounsiar
- IHU Méditerranée Infection, Marseille, France.,Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique- Hôpitaux de Marseille (AP-HM), MEPHI, Marseille, France
| | - Jean-Pierre Baudoin
- IHU Méditerranée Infection, Marseille, France.,Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique- Hôpitaux de Marseille (AP-HM), MEPHI, Marseille, France
| | - Sihem Hannat
- IHU Méditerranée Infection, Marseille, France.,Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique- Hôpitaux de Marseille (AP-HM), MEPHI, Marseille, France
| | - Philippe Decloquement
- IHU Méditerranée Infection, Marseille, France.,Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique- Hôpitaux de Marseille (AP-HM), MEPHI, Marseille, France
| | - Eric Chabrieres
- IHU Méditerranée Infection, Marseille, France.,Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique- Hôpitaux de Marseille (AP-HM), MEPHI, Marseille, France
| | - Sarah Aherfi
- IHU Méditerranée Infection, Marseille, France.,Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique- Hôpitaux de Marseille (AP-HM), MEPHI, Marseille, France
| | - Bernard La Scola
- IHU Méditerranée Infection, Marseille, France.,Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique- Hôpitaux de Marseille (AP-HM), MEPHI, Marseille, France
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Abstract
Bacteriophages mediate horizontal gene transfer through a mechanism known as transduction. Phage transduction carried out in the laboratory involves a bacterial donor and a recipient, both of which are susceptible to infection by the phage of interest. Phage is propagated in the donor, concentrated, and exposed transiently to recipient at different multiplicity of infection ratios. Transductants are selected for the desired phenotype by culture on selective medium. Here we describe transduction of ermB conferring resistance to erythromycin by the C. difficile phage ϕC2.
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Affiliation(s)
- Shan Goh
- Department of Pathology and Pathogen Biology, The Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire, UK.
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3
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Abstract
Escherichia coli leu(+) episomes were transferred to Salmonella typhimurium. The levels of two leucine-forming enzymes were normal (low) in the resulting merodiploids, suggesting that the putative Samonella leucine repressor recognizes the Escherichia leucine operator.
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Hedges RW. Transduction mechanisms of bacteriophage epsilon 15. I. General properties of the system. Genet Res (Camb) 1971; 18:9-19. [PMID: 5211366 DOI: 10.1017/s0016672300012362] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
SUMMARYBacteriophageεγis capable of transduction both by replacement of a genetic segment of the recipient by the homologous genetic material from the donor strain and by the formation of defective transducing particles capable of lysogenizing the recipient strain ofS. anatum.The isolation of strains carrying such prophages, which have incorporated the lactose or arabinose operons, is reported. Lysogenic strains, carrying both normal and defective transducing prophage, form high-frequency transducing lysates. Other strains, carrying only defective prophage, show evidence that the association of prophage genes and transduced materials is stable since the loss of one frequently entails loss of the other.
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O'Neil DM, Sypherd PS. Cotransduction of strA and ribosomal protein cistrons in Escherichia coli-Salmonella typhimurium hybrids. J Bacteriol 1971; 105:947-56. [PMID: 4929285 PMCID: PMC248523 DOI: 10.1128/jb.105.3.947-956.1971] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Genetic mapping of ribosomal protein cistrons of Salmonella typhimurium and Escherichia coli was performed by phage P1 mediated, generalized transduction. From an E. coli hybrid strain which carried a S. typhimuirum F' factor, an E. coli strain was constructed which had integrated S. typhimurium genetic material including the region of the strA locus. Salmonella genetic material from this hybrid was transduced into E. coli recipients. The ribosomal protein electrophoretic patterns of these hybrid transductants were correlated with the presence of markers contributed by each parent. The results of these studies indicate that cistrons for at least three characteristic S. typhimurium and two E. coli 30S ribosomal proteins are closely linked to the strA locus on the genetic maps of both organisms. At least one cistron coding for a 50S ribosomal protein is also closely linked to this locus on both maps. These findings support the concept that cistrons coding for the ribosomal proteins are clustered in one area of the genome. Mutations to spectinomycin and streptomycin resistance are closely linked in S. typhimurium and are located at strA.
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Enomoto M, Yamaguchi S. Different frequencies of cotransduction of motC and H1 in Salmonella. Genet Res (Camb) 1969; 14:45-52. [PMID: 5364957 DOI: 10.1017/s001667230000183x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The frequency of cotransduction ofmotCandH1in Salmonella has been investigated, using four Salmonella serotypes and many serotypic recombinants as donors andS. typhimurium motCmutant as recipient. The frequency varied with the four serotypes from 7% to 52%. It is suggested that the difference in frequency arises from not only differences in genetic homology between the chromosome of the recipient and the fragment from the donor, but also from differences in genetic composition of the chromosome fragments carried by the phage. The frequency of serotypic recombinants selected formotC+andH1gene of the donor is generally higher than with recombinants selected forflaK+andH1. The difference in genetic homology betweenS. typhimuriumand other species is more marked in the region betweenH1audflaKthan betweenmotCandH1.
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Abstract
An azaserine-resistant derivative of Escherichia coli B/UV, AZA/R(1), was found to carry a mutator gene. This gene, designated mutS1, was mapped by means of conjugation and P1kc-mediated transduction. The mutS1 gene was cotransduced with argB at a frequency of 2.4%; the gene order in this region of the chromosome is thy argB mutS1. To determine whether a relationship commonly exists between azaserine resistance and the mutator property, 12 additional azaserine-resistant derivatives of B/UV were developed and tested for the mutator phenotype. None of the twelve was a mutator strain. The level of azaserine resistance was not increased over that of the recipient parent when mutS1 was transduced to an azaserine-susceptible strain. Reversion studies indicated that mutS1 induced adenosine-ribosylthymine to guanosine-cytidine and guanosine-cytidine to adenosine-ribosylthymine transitions. Because such mutational changes are suppressible with deoxynucleosides when induced by base analogues, an attempt was made to suppress the mutator activity of mutS1 by the addition of deoxyribonucleosides to the medium. No suppression was found. Recombinants were prepared containing mutS1 and the Treffers mutator gene of E. coli K-12. The effect of the mutator genes appears to be additive.
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