MtrA acts as a bifunctional modulator of the GlnR-controlled nitrogen regulon in
5 affiliations
- 1Institute of Medical Biology of the Polish Academy of Sciences, Lodowa 106, Łódź, 93-232, Poland.
- 2Department of Immunology and Infectious Biology, Faculty of Biology and Environmental Protection, University of Łódz, Banacha 12/16, Łódź, 90-237, Poland.
- 3BioMedChem Doctoral School of the University of Łódź and Łódź Institutes of the Polish Academy of Sciences, Matejki 21/23, Łódź, 90-237, Poland.
- 4Centre for Digital Biology and Biomedical Science - Biobank, Faculty of Biology and Environmental Protection, University of Łódź, Pomorska 139, Łódź, 90-235, Poland.
- 5Department of Molecular Microbiology, Faculty of Biology and Environmental Protection, University of Łódź, Banacha 12/16, Łódź, 90-237, Poland.
Abstract
Nitrogen metabolism is a crucial factor in bacterial survival and adaptation, its regulation in Mycobacterium spp. remains only partly understood. In this study, we identify a previously unrecognized role for the response regulator MtrA in the regulation of nitrogen metabolism in Mycobacterium smegmatis alongside the well-known master regulator GlnR. Transcriptomic profiling under nitrogen-limiting conditions revealed that MtrA modulates the GlnR regulon by exerting both supportive and opposing effects. For one subset of genes, including those encoding enzymes for proline and histidine utilization, MtrA acts as a positive regulator with GlnR to achieve maximal induction. For another subset, particularly nutrient transport systems such as amino acid permeases and ammonium transporters, MtrA functions antagonistically, repressing expression to prevent metabolic imbalance and maintain carbon–nitrogen balance. Electrophoretic mobility shift assays confirmed that, although MtrA and GlnR share similar binding motifs, they recognize distinct structural features, thereby providing specific control over this regulatory system. Physiological analyses corroborated these findings, showing that the loss of MtrA impaired growth on histidine and proline but enhanced growth on nitrogen sources derived from purines. Together, these data establish a hierarchical model in which GlnR serves as the master nitrogen regulator, while MtrA fine-tunes gene expression to balance nutrient acquisition with cellular state. This dual control mechanism provides an adaptive advantage for mycobacteria in nutrient-limited environments.
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BibTeX
@article{plocinska2026mtra,
title = {{MtrA acts as a bifunctional modulator of the GlnR-controlled nitrogen regulon in}},
author = {Renata Płocińska and Przemysław Płociński and Małgorzata Korycka-Machała and Anna Brzostek and Magdalena Kuzioła and Katarzyna Struś and Marcin Słomka and Bożena Dziadek and Jarosław Dziadek},
journal = {Current Research in Microbial Sciences},
year = {2026},
month = oct,
doi = {10.1016/j.crmicr.2026.100670},
url = {https://doi.org/10.1016/j.crmicr.2026.100670},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - MtrA acts as a bifunctional modulator of the GlnR-controlled nitrogen regulon in
AU - Renata Płocińska
AU - Przemysław Płociński
AU - Małgorzata Korycka-Machała
AU - Anna Brzostek
AU - Magdalena Kuzioła
AU - Katarzyna Struś
AU - Marcin Słomka
AU - Bożena Dziadek
AU - Jarosław Dziadek
PY - 2026
DA - 2026/10/16
JO - Current Research in Microbial Sciences
DO - 10.1016/j.crmicr.2026.100670
UR - https://doi.org/10.1016/j.crmicr.2026.100670
AB - Nitrogen metabolism is a crucial factor in bacterial survival and adaptation, its regulation in Mycobacterium spp. remains only partly understood. In this study, we identify a previously unrecognized role for the response regulator MtrA in the regulation of nitrogen metabolism in Mycobacterium smegmatis alongside the well-known master regulator GlnR. Transcriptomic profiling under nitrogen-limiting conditions revealed that MtrA modulates the GlnR regulon by exerting both supportive and opposing effects. For one subset of genes, including those encoding enzymes for proline and histidine utilization, MtrA acts as a positive regulator with GlnR to achieve maximal induction. For another subset, particularly nutrient transport systems such as amino acid permeases and ammonium transporters, MtrA functions antagonistically, repressing expression to prevent metabolic imbalance and maintain carbon–nitrogen balance. Electrophoretic mobility shift assays confirmed that, although MtrA and GlnR share similar binding motifs, they recognize distinct structural features, thereby providing specific control over this regulatory system. Physiological analyses corroborated these findings, showing that the loss of MtrA impaired growth on histidine and proline but enhanced growth on nitrogen sources derived from purines. Together, these data establish a hierarchical model in which GlnR serves as the master nitrogen regulator, while MtrA fine-tunes gene expression to balance nutrient acquisition with cellular state. This dual control mechanism provides an adaptive advantage for mycobacteria in nutrient-limited environments.
SN - 2666-5174
ER -