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ORIGINAL RESEARCH article

Front. Microbiol.
Sec. Microbial Physiology and Metabolism
Volume 15 - 2024 | doi: 10.3389/fmicb.2024.1448277

Rel-dependent decrease in the expression of ribosomal protein genes by inhibition of the respiratory electron transport chain in Mycobacterium smegmatis

Provisionally accepted
Na-Kyeong Kim Na-Kyeong Kim Jong-Eun Baek Jong-Eun Baek Ye-Jin Lee Ye-Jin Lee Yuna Oh Yuna Oh Jeong-Il Oh Jeong-Il Oh *
  • Pusan National University, Busan, Republic of Korea

The final, formatted version of the article will be published soon.

    In this study, we demonstrated that both the expression of most ribosomal protein genes and the amount of ribosomes were decreased in the aa3 mutant of Mycobacterium smegmatis, in which the major terminal oxidase (aa3 cytochrome c oxidase) of the respiratory electron transport chain (ETC) is inactivated, compared to those in the wild-type strain. Deletion of the rel gene encoding the major (p)ppGpp synthetase in the background of the aa3 mutant restored the reduced expression of ribosomal protein genes, suggesting that inhibition of the respiratory ETC leads to the Rel-dependent stringent response (SR) in this bacterium. Both a decrease in the expression of ribosomal protein genes by overexpression of rel and the increased expression of rel in the aa3 mutant relative to the wild-type strain support the Rel-dependent induction of SR in the aa3 mutant. We also demonstrated that the expression of ribosomal protein genes was decreased in M. smegmatis exposed to respiration-inhibitory conditions, such as KCN and bedaquiline treatment, null mutation of the cytochrome bcc1 complex, and hypoxia. The MprBA-SigE-SigB regulatory pathway was implicated in both the increased expression of rel and the decreased expression of ribosomal protein genes in the aa3 mutant of M. smegmatis.

    Keywords: electron transport chain, MprBA two-component system, Mycobacterium, Respiration, ribosome, sigB, SiGe, Stringent response

    Received: 13 Jun 2024; Accepted: 24 Jul 2024.

    Copyright: © 2024 Kim, Baek, Lee, Oh and Oh. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Jeong-Il Oh, Pusan National University, Busan, Republic of Korea

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