VapC21 Toxin Contributes to Drug-Tolerance and Interacts With Non-cognate VapB32 Antitoxin in Mycobacterium tuberculosis

Sharma, A and Chattopadhyay, G and Chopra, P and Bhasin, M and Thakur, C and Agarwal, S and Ahmed, S and Chandra, N and Varadarajan, R and Singh, R (2020) VapC21 Toxin Contributes to Drug-Tolerance and Interacts With Non-cognate VapB32 Antitoxin in Mycobacterium tuberculosis. In: Frontiers in Microbiology, 11 .

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Abstract

The prokaryotic ubiquitous Toxin-antitoxin (TA) modules encodes for a stable toxin and an unstable antitoxin. VapBC subfamily is the most abundant Type II TA system in M. tuberculosis genome. However, the exact physiological role for most of these Type II TA systems are still unknown. Here, we have comprehensively characterized the VapBC21 TA locus from M. tuberculosis. The overexpression of VapC21 inhibited mycobacterial growth in a bacteriostatic manner and as expected, growth inhibition was abrogated upon co-expression of the cognate antitoxin, VapB21. We observed that the deletion of vapC21 had no noticeable influence on the in vitro and in vivo growth of M. tuberculosis. Using co-expression and biophysical studies, we observed that in addition to VapB21, VapC21 is also able to interact with non-cognate antitoxin, VapB32. The strength of interaction varied between the cognate and non-cognate TA pairs. The overexpression of VapC21 resulted in differential expression of approximately 435 transcripts in M. tuberculosis. The transcriptional profiles obtained upon ectopic expression of VapC21 was similar to those reported in M. tuberculosis upon exposure to stress conditions such as nutrient starvation and enduring hypoxic response. Further, VapC21 overexpression also led to increased expression of WhiB7 regulon and bacterial tolerance to aminoglycosides and ethambutol. Taken together, these results indicate that a complex network of interactions exists between non-cognate TA pairs and VapC21 contributes to drug tolerance in vitro. © Copyright © 2020 Sharma, Chattopadhyay, Chopra, Bhasin, Thakur, Agarwal, Ahmed, Chandra, Varadarajan and Singh.

Item Type:	Journal Article
Publication:	Frontiers in Microbiology
Publisher:	Frontiers Media S.A.
Additional Information:	Copyright for this article belongs to Frontiers Media S.A.
Keywords:	aminoglycoside; antitoxin; complementary DNA; ethambutol; hygromycin; isoniazid; reduced nicotinamide adenine dinucleotide; rifampicin; unclassified drug; VapB32 toxin; VapC21 toxin, animal experiment; animal model; Article; bacterial growth; bacterial strain; bacteriostasis; bacterium culture; biosynthesis; controlled study; down regulation; drug interaction; drug tolerance; ectopic expression; Escherichia coli; female; gene deletion; gene overexpression; gene regulatory network; growth inhibition; hypoxia; in vitro study; lipid metabolism; mycobacteriophage; Mycobacterium smegmatis; Mycobacterium tuberculosis; nonhuman; protein expression; protein protein interaction; protein purification; protein unfolding; real time polymerase chain reaction; RNA sequence; RNA sequencing; Southern blotting; thermostability; upregulation
Department/Centre:	Division of Biological Sciences > Biochemistry Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	25 Nov 2020 09:47
Last Modified:	25 Nov 2020 09:47
URI:	http://eprints.iisc.ac.in/id/eprint/66824

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