The Putative Endonuclease Activity of MutL Is Required for the Segmental Gene Conversion Events That Drive Antigenic Variation of the Lyme Disease Spirochete
The Lyme disease spirochete Borrelia burgdorferi, encodes an elaborate antigenic variation system that promotes the ongoing variation of a major surface lipoprotein, VlsE. Changes in VlsE are continual and always one step ahead of the host acquired immune system, which requires 1–2 weeks to generate...
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| Format: | Article |
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Frontiers Media S.A.
2022-05-01
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| Series: | Frontiers in Microbiology |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fmicb.2022.888494/full |
| _version_ | 1817991520802832384 |
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| author | Mildred Castellanos Theodore B. Verhey Madeleine Goldstein George Chaconas George Chaconas |
| author_facet | Mildred Castellanos Theodore B. Verhey Madeleine Goldstein George Chaconas George Chaconas |
| author_sort | Mildred Castellanos |
| collection | DOAJ |
| description | The Lyme disease spirochete Borrelia burgdorferi, encodes an elaborate antigenic variation system that promotes the ongoing variation of a major surface lipoprotein, VlsE. Changes in VlsE are continual and always one step ahead of the host acquired immune system, which requires 1–2 weeks to generate specific antibodies. By the time this happens, new VlsE variants have arisen that escape immunosurveillance, providing an avenue for persistent infection. This antigenic variation system is driven by segmental gene conversion events that transfer information from a series of silent cassettes (vls2-16) to the expression locus, vlsE. The molecular details of this process remain elusive. Recombinational switching at vlsE is RecA-independent and the only required factor identified to date is the RuvAB branch migrase. In this work we have used next generation long-read sequencing to analyze the effect of several DNA replication/recombination/repair gene disruptions on the frequency of gene conversions at vlsE and report a requirement for the mismatch repair protein MutL. Site directed mutagenesis of mutL suggests that the putative MutL endonuclease activity is required for recombinational switching at vlsE. This is the first report of an unexpected essential role for MutL in a bacterial recombination system and expands the known function of this protein as well as our knowledge of the details of the novel recombinational switching mechanism for vlsE variation. |
| first_indexed | 2024-04-14T01:14:24Z |
| format | Article |
| id | doaj.art-c1bb076032d546749ac4f9aac74d96d0 |
| institution | Directory Open Access Journal |
| issn | 1664-302X |
| language | English |
| last_indexed | 2024-04-14T01:14:24Z |
| publishDate | 2022-05-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Microbiology |
| spelling | doaj.art-c1bb076032d546749ac4f9aac74d96d02022-12-22T02:20:56ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2022-05-011310.3389/fmicb.2022.888494888494The Putative Endonuclease Activity of MutL Is Required for the Segmental Gene Conversion Events That Drive Antigenic Variation of the Lyme Disease SpirocheteMildred Castellanos0Theodore B. Verhey1Madeleine Goldstein2George Chaconas3George Chaconas4Department of Biochemistry and Molecular Biology, Cumming School of Medicine, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, CanadaDepartment of Biochemistry and Molecular Biology, Cumming School of Medicine, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, CanadaDepartment of Biochemistry and Molecular Biology, Cumming School of Medicine, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, CanadaDepartment of Biochemistry and Molecular Biology, Cumming School of Medicine, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, CanadaDepartment of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, CanadaThe Lyme disease spirochete Borrelia burgdorferi, encodes an elaborate antigenic variation system that promotes the ongoing variation of a major surface lipoprotein, VlsE. Changes in VlsE are continual and always one step ahead of the host acquired immune system, which requires 1–2 weeks to generate specific antibodies. By the time this happens, new VlsE variants have arisen that escape immunosurveillance, providing an avenue for persistent infection. This antigenic variation system is driven by segmental gene conversion events that transfer information from a series of silent cassettes (vls2-16) to the expression locus, vlsE. The molecular details of this process remain elusive. Recombinational switching at vlsE is RecA-independent and the only required factor identified to date is the RuvAB branch migrase. In this work we have used next generation long-read sequencing to analyze the effect of several DNA replication/recombination/repair gene disruptions on the frequency of gene conversions at vlsE and report a requirement for the mismatch repair protein MutL. Site directed mutagenesis of mutL suggests that the putative MutL endonuclease activity is required for recombinational switching at vlsE. This is the first report of an unexpected essential role for MutL in a bacterial recombination system and expands the known function of this protein as well as our knowledge of the details of the novel recombinational switching mechanism for vlsE variation.https://www.frontiersin.org/articles/10.3389/fmicb.2022.888494/fullLyme diseaseborreliosisBorreliaantigenic variationvlsEgene conversion |
| spellingShingle | Mildred Castellanos Theodore B. Verhey Madeleine Goldstein George Chaconas George Chaconas The Putative Endonuclease Activity of MutL Is Required for the Segmental Gene Conversion Events That Drive Antigenic Variation of the Lyme Disease Spirochete Frontiers in Microbiology Lyme disease borreliosis Borrelia antigenic variation vlsE gene conversion |
| title | The Putative Endonuclease Activity of MutL Is Required for the Segmental Gene Conversion Events That Drive Antigenic Variation of the Lyme Disease Spirochete |
| title_full | The Putative Endonuclease Activity of MutL Is Required for the Segmental Gene Conversion Events That Drive Antigenic Variation of the Lyme Disease Spirochete |
| title_fullStr | The Putative Endonuclease Activity of MutL Is Required for the Segmental Gene Conversion Events That Drive Antigenic Variation of the Lyme Disease Spirochete |
| title_full_unstemmed | The Putative Endonuclease Activity of MutL Is Required for the Segmental Gene Conversion Events That Drive Antigenic Variation of the Lyme Disease Spirochete |
| title_short | The Putative Endonuclease Activity of MutL Is Required for the Segmental Gene Conversion Events That Drive Antigenic Variation of the Lyme Disease Spirochete |
| title_sort | putative endonuclease activity of mutl is required for the segmental gene conversion events that drive antigenic variation of the lyme disease spirochete |
| topic | Lyme disease borreliosis Borrelia antigenic variation vlsE gene conversion |
| url | https://www.frontiersin.org/articles/10.3389/fmicb.2022.888494/full |
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