We have identified and characterized the first sRNA, DsrABb, in the Lyme disease spirochete, <em>Borrelia burgdorferi</em>; as well as, identified a non-canonical RNA chaperone Hfq. The alternative sigma factor RpoS (sigma 38 or sigma S) plays a central role in the reciprocal regulation of the virulence-associated major outer surface proteins OspC and OspA. Temperature is one of the key environmental signals controlling RpoS, but the molecular mechanism by which the signal is transduced remains unknown. DsrABb post-transcriptionally regulates the alternative sigma factor RpoS in response to an increase in temperature, associated with the tick to mammal transmission signal. A novel 5' end of the <em>rpoS</em> mRNA was identified and DsrABb has the potential of extensively base-pairing with the upstream region of this <em>rpoS</em> transcript. We demonstrate that <em>B. burgdorferi</em> strains lacking DsrABb do not upregulate RpoS and OspC in response to an increase in temperature, but do regulate RpoS and OspC in response to changes in pH and cell density. The 5' and 3' ends of DsrABb were mapped, demonstrating that at least four species exist with sizes ranging from 213 to 352 nucleotides. We demonstrate and characterize in vitro the interaction between DsrA and upstream region of <em>rpoS</em> mRNA. We hypothesize that DsrABb binds to the upstream region of the <em>rpoS</em> mRNA and stimulates translation by releasing the Shine-Dalgarno sequence and start site from a stable secondary structure. Therefore, we postulate that DsrABb is a molecular thermometer regulating RpoS in <em>Borrelia burgdorferi</em>.
| Identifer | oai:union.ndltd.org:MONTANA/oai:etd.lib.umt.edu:etd-01042008-110120 |
| Date | 06 February 2008 |
| Creators | Lybecker, Meghan Catherine |
| Contributors | Mike Minnick, D. Scott Samuels, Michele McGuirl, Jean-Marc Lanchy, Kent Sugden |
| Publisher | The University of Montana |
| Source Sets | University of Montana Missoula |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.umt.edu/theses/available/etd-01042008-110120/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Montana or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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