Abstract:
A primary target of Mycobacterium tuberculosis is the human alveolar macrophage.
Infection by this bacterium can lead to a variety of responses, such as apoptosis,
autophagy, and necrosis, which may be involved in controlling the infection. M.
tuberculosis has evolved mechanisms to evade or use the host-mediated processes to its
advantage. One of them, autophagy, has been shown to be suppressed by the bacterium.
The goal of this study was to identify mycobacterial genes involved in autophagy
inhibition. A transposon mutant bank was created using the M. tuberculosis virulent
strain H37Rv and temperature-sensitive plasmid containing transposon Tn6753. U937
human macrophages were infected with the mutant library and individual clones were
screened for attenuation. Once mutants showing impaired ability to grow within the host
macrophage were identified, they were screened for an inability to inhibit autophagy.
Fifty-four mutants exhibiting attenuation within the macrophage were identified. An
LC3-staining assay was performed on eighteen clones that showed the greatest
attenuation. Three of them were not associated with autophagy inhibition. The
sequencing of the inactivated genes is in progress.
