title: The application of tetracyclineregulated gene expression systems in the validation of novel drug targets in Mycobacterium tuberculosis.
abstract: Although efforts to identify novel therapies for the treatment of tuberculosis have led to the identification of several promising drug candidates, the identification of high-quality hits from conventional whole-cell screens remains disappointingly low. The elucidation of the genome sequence of Mycobacterium tuberculosis (Mtb) facilitated a shift to target-based approaches to drug design but these efforts have proven largely unsuccessful. More recently, regulated gene expression systems that enable dose-dependent modulation of gene expression have been applied in target validation to evaluate the requirement of individual genes for the growth of Mtb both in vitro and in vivo. Notably, these systems can also provide a measure of the extent to which putative targets must be depleted in order to manifest a growth inhibitory phenotype. Additionally, the successful implementation of Mtb strains engineered to under-express specific molecular targets in whole-cell screens has enabled the simultaneous identification of cell-permeant inhibitors with defined mechanisms of action. Here, we review the application of tetracycline-regulated gene expression systems in the validation of novel drug targets in Mtb, highlighting both the strengths and limitations associated with this approach to target validation.
authors: South African Medical Research Council/National Health Laboratory Service/University of Cape Town Molecular Mycobacteriology Research Unit Cape Town, South Africa ; DST/NRF Centre of Excellence for Biomedical TB Research, Institute of Infectious Disease and Molecular Medicine and Division of Medical Microbiology, Faculty of Health Sciences, University of Cape Town Cape Town, South Africa.
authors: Joanna C
authors: JC
authors: Evans
authors: South African Medical Research Council/National Health Laboratory Service/University of Cape Town Molecular Mycobacteriology Research Unit Cape Town, South Africa ; DST/NRF Centre of Excellence for Biomedical TB Research, Institute of Infectious Disease and Molecular Medicine and Division of Medical Microbiology, Faculty of Health Sciences, University of Cape Town Cape Town, South Africa.
authors: Valerie
authors: V
authors: Mizrahi
keywords: Mycobacterium tuberculosis; drug discovery; hypomorphs; regulated gene expression; target validation; target-based whole cell screening