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bioRxiv · 10.1101/2021.11.16.468908

The mycobacterial mutasome: composition and recruitment in live cells

Gessner, S.·Martin, Z. A.-M.·Reiche, M. A.·Santos, J.·Dhar, N.·Dinkele, R.·de Wet, T. J.·Ramudzuli, A.·Anoosheh, S.·Lang, D. M.·Aaron, J.·Chew, T. L.·Herrmann, J.·Mueller, R.·McKinney, J. D.·Woodgate, R.·Mizrahi, V.·Lamers, M.·Warner, D. F.
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Abstract

A DNA damage-inducible mutagenic gene cassette has been implicated in the emergence of drug resistance in Mycobacterium tuberculosis during anti-tuberculosis (TB) chemotherapy. However, the molecular composition and operation of the encoded "mycobacterial mutasome" - minimally comprising DnaE2 polymerase and ImuA' and ImuB accessory proteins - remain elusive. Following exposure of mycobacteria to DNA damaging agents, we observe that DnaE2 and ImuB co-localize with the DNA polymerase III {beta} subunit ({beta} clamp) in distinct intracellular foci. Notably, genetic inactivation of the mutasome in an imuBAAAAGG mutant containing a disrupted {beta} clamp-binding motif abolishes ImuB-{beta} clamp focus formation, a phenotype recapitulated pharmacologically by treating bacilli with griselimycin and in biochemical assays in which this {beta} clamp-binding antibiotic collapses pre-formed ImuB-{beta} clamp complexes. These observations establish the essentiality of the ImuB-{beta} clamp interaction for mutagenic DNA repair in mycobacteria, identifying the mutasome as target for adjunctive therapeutics designed to protect anti-TB drugs against emerging resistance.

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Gessner, S., Martin, Z. A.-M., Reiche, M. A., Santos, J., Dhar, N., Dinkele, R., de Wet, T. J., Ramudzuli, A., Anoosheh, S., Lang, D. M., Aaron, J., Chew, T. L., Herrmann, J., Mueller, R., McKinney, J. D., Woodgate, R., Mizrahi, V., Lamers, M., Warner, D. F.. 2021-11-17. The mycobacterial mutasome: composition and recruitment in live cells. https://doi.org/10.1101/2021.11.16.468908

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