The DedA protein family is a highly conserved family of membrane proteins, with members present throughout all domains of life: Bacteria, Archaea, and Eukarya. Investigation of the DedA membrane protein family began with the isolation of BC202, an Escherichia coli mutant with in-frame deletions of two DedA proteins of unknown function (YqjA and YghB) that share 61% amino acid identity. BC202 demonstrates temperature sensitivity, inefficient cell division, an altered phospholipid composition, increased expression of extracytoplasmic stress response pathways, as well as an inability to maintain the cell membrane proton motive force (PMF). Additionally, Borrelia burgdorferi has a single DedA homolog (Bb0250), deletion of this gene was only possible in the presence of a cloned and inducible copy of the gene. The essentiality of the DedA membrane protein family in B. burgdorferi, instigated the investigation into the essentiality of the family in E. coli, which has eight individually non-essential DedA genes. Discussed herein is the generation of mutants in which all eight E. coli DedA genes are deleted, which again, was only possible in the presence of a cloned and arabinose inducible DedA protein. One mutant was further characterized, BAL801 (cloned EcDedA), identifying that the essential function of the E. coli DedA membrane protein family may be to play a vital role in the proper maintenance and segregation of the bacterial nucleoid. Also, complementation of BC202s temperature sensitivity and cell division defects are complemented by only four of the eight E. coli DedA proteins (C-group; yqjA, yghB, yohD, and yabI), the remaining four were subsequently classified as non-complementing (NC-group; ydjX, ydjZ, yqaA, and dedA). The identification of the C- and NC-groups within E. colis DedA proteins, lead to the generation of another mutant series in which the NC-group and the C-group proteins were independently deleted, to aide in the continued understanding of this essential and redundant membrane protein family.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-04032013-120222 |
| Date | 11 April 2013 |
| Creators | Boughner, Lisa A. |
| Contributors | Doerrler, William T., Hand, Steven C., LaRock, Paul A., Whitehead, Andrew, Lee, Matthew R. |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-04032013-120222/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached herein 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 LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, 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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