Description
TitleIdentification and characterization of Mycobacterium tuberculosis VapC50 toxin
Date Created2017
Other Date2017-01 (degree)
Extent1 online resource (ix, 70 p. : ill.)
DescriptionTuberculosis is a major health concern for a large portion of the world’s population, despite its reputation as an ancient disease. One of the main concerns is the development of latent tuberculosis, where Mycobacterium tuberculosis remains dormant for months or years before being reactivated. Among all bacteria studied thus far, M. tuberculosis has the most toxin-antitoxin (TA) systems, with 88 discovered so far, 50 of which are VapBC systems. It is thought that these TA systems may aid the bacteria in establishing and/or maintaining M. tuberculosis cells in this nonreplicating persistent state characteristic of latent tuberculosis. TA systems have been shown to respond to various stressors that bacteria may encounter, including hypoxia, host immune responses, and nutrient starvation. VapBC, which is a type II TA system, is composed of an unstable antitoxin protein, VapB, that binds to the stable PIN domain-containing VapC toxin protein and blocks its activity. The goals of this M.S. research project were to isolate, characterize and identify the RNA target of one M. tuberculosis VapC toxin, VapC50. To this end, we first discovered that the annotated VapC50 gene was incorrect, and instead identified and cloned the correct VapC50 toxin. Expression of VapC50 in Escherichia coli resulted in growth inhibition, however, expression Mycobacterium smegmatis did not inhibit growth. Purification of recombinant VapC50 protein proved to be a difficult task and was only successful after the third trial, when the protein was expressed at 30C instead of 37C. Since most of the analysis of VapC toxins published highlight their tRNA cleaving ability, purified VapC50 was used to conduct a tRNA cleavage assay with all 45 tRNAs in M. tuberculosis. None of the 45 tRNAs were cleaved by VapC50, suggesting that this toxin may instead have a novel physiological role in this pathogen.
NoteM.S.
NoteIncludes bibliographical references
Noteby Jillian Nicole Cortese
Genretheses, ETD graduate
Languageeng
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.