Consequences of a mobile genetic element integrated at secondary locations
Thesis (Ph. D.)--Massachusetts Institute of Technology, Microbiology Graduate Program, 2013.
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| Format: | Thesis |
| Language: | eng |
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Massachusetts Institute of Technology
2014
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| Online Access: | http://hdl.handle.net/1721.1/83743 |
| _version_ | 1811075778804187136 |
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| author | Menard, Kayla L. (Kayla Lynne) |
| author2 | Alan D. Grossman. |
| author_facet | Alan D. Grossman. Menard, Kayla L. (Kayla Lynne) |
| author_sort | Menard, Kayla L. (Kayla Lynne) |
| collection | MIT |
| description | Thesis (Ph. D.)--Massachusetts Institute of Technology, Microbiology Graduate Program, 2013. |
| first_indexed | 2024-09-23T10:11:45Z |
| format | Thesis |
| id | mit-1721.1/83743 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T10:11:45Z |
| publishDate | 2014 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/837432019-04-11T11:29:01Z Consequences of a mobile genetic element integrated at secondary locations Menard, Kayla L. (Kayla Lynne) Alan D. Grossman. Massachusetts Institute of Technology. Microbiology Graduate Program. Massachusetts Institute of Technology. Microbiology Graduate Program. Microbiology Graduate Program. Thesis (Ph. D.)--Massachusetts Institute of Technology, Microbiology Graduate Program, 2013. Cataloged from PDF version of thesis. Includes bibliographical references (pages 91-96). Integrative and conjugative elements (ICEs) are widespread mobile genetic elements that are integrated in bacterial chromosomes, but can excise and transfer to a recipient through conjugation. ICEs are important agents of evolution, contributing to the acquisition of new traits, including antibiotic resistance. Many ICEs are site-specific in that they integrate preferentially into a primary attachment site in the bacterial chromosome. Site-specific ICEs can integrate into secondary locations, but little is known about the consequences of integration. Using ICEBs1, a site-specific ICE from Bacillus subtilis, I found that integration into secondary attachment sites is detrimental to both ICEBs1 and the host cell. Integration at secondary locations is detrimental to ICEBsJ. Once integrated in the chromosome, excision of ICEBs1 from all secondary attachment sites analyzed was either reduced (4 sites) or undetectable (3 sites) compared to ICEBs1 excision from the primary site. Additionally, from two of the four secondary sites that exhibited reduced but detectable excision, the excised, circular form of ICEBs1 was present at lower levels than expected, indicating that circular ICEBs1 may be unstable. Defects in excision and stability of ICEBs] severely limit its ability to spread to other cells. Integration at secondary locations is detrimental to the host cell. Induction of ICEBs1 gene expression in secondary integration sites resulted in a defect in cell proliferation and/or viability, as well as induction of the SOS response. These effects are likely due to DNA damage resulting from plasmid-like, rolling-circle replication of the excision-defective ICEBs1 in the chromosome. Consistent with this model, deletion of ICEBs] replication genes (nicK and helP) alleviated the proliferation and viability defects. Implications for the evolution of ICEs. These previously unrecognized detrimental effects may provide selective pressure against propagation of ICEBs1 in secondary attachment sites. Such detrimental effects could explain the maintenance and prevalence of site-specific integration among ICEs. by Kayla L. Menard. Ph.D. 2014-01-09T19:50:23Z 2014-01-09T19:50:23Z 2013 Thesis http://hdl.handle.net/1721.1/83743 864715573 eng M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 96 pages application/pdf Massachusetts Institute of Technology |
| spellingShingle | Microbiology Graduate Program. Menard, Kayla L. (Kayla Lynne) Consequences of a mobile genetic element integrated at secondary locations |
| title | Consequences of a mobile genetic element integrated at secondary locations |
| title_full | Consequences of a mobile genetic element integrated at secondary locations |
| title_fullStr | Consequences of a mobile genetic element integrated at secondary locations |
| title_full_unstemmed | Consequences of a mobile genetic element integrated at secondary locations |
| title_short | Consequences of a mobile genetic element integrated at secondary locations |
| title_sort | consequences of a mobile genetic element integrated at secondary locations |
| topic | Microbiology Graduate Program. |
| url | http://hdl.handle.net/1721.1/83743 |
| work_keys_str_mv | AT menardkaylalkaylalynne consequencesofamobilegeneticelementintegratedatsecondarylocations |