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The roles of selected sigma factor genes in Mycobacterium tuberculosis

Chan, Bosco How Yeung; (2006) The roles of selected sigma factor genes in Mycobacterium tuberculosis. Masters thesis (MPhil), UCL (University College London). Green open access


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Mycobacterium tuberculosis is a major cause of mortality worldwide and it has been estimated that a third of the world population is infected with Mycobacterium tuberculosis. Each year 8-10 million new active pulmonary cases arise and 2 million patients die of the disease. To improve treatment and prevention of disease it is important to gain further understanding of how this human pathogen adapts to and survives the conditions generated by host defence processes. Gene regulation is important in enabling the pathogen to adapt to the various environmental conditions it encounters, and the use of sigma factors is one way to achieve this. In this study, phenotypic analyses of an existing M. tuberculosis mutant strain lacking sigC were undertaken. A s/gC-complemented strain with a functional sigC gene is used to confirm that the phenotype of the sigC mutant strain is sigC specific. The role of o c in global regulation of gene expression in M. tuberculosis is investigated by a comparative transcriptome study of the wild type and the AsigC mutant strains via microarray analysis. Furthermore, the transcriptional start site for sigC is identified via primer extension studies, providing insight into the regulative nature of a and the identification of the putative promoter sequence of a . In addition, sigB, which codes for the principal-sigma factor-like aB, is targeted for mutagenesis in M. tuberculosis. This process has been complicated by the discovery of the polycistronic nature of sigB with the downstream gene ideR, which codes for an essential regulator for iron metabolism in M. tuberculosis. This has led to a revision of the gene deletion strategy for sigB in M. tuberculosis.

Type: Thesis (Masters)
Qualification: MPhil
Title: The roles of selected sigma factor genes in Mycobacterium tuberculosis
Identifier: PQ ETD:594015
Open access status: An open access version is available from UCL Discovery
Language: English
Additional information: Thesis digitised by ProQuest. Third party copyright material has been removed from the ethesis. Images identifying individuals have been redacted or partially redacted to protect their identity.
UCL classification: UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Pop Health Sciences > Institute of Epidemiology and Health
URI: http://discovery.ucl.ac.uk/id/eprint/1446368
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