Competence is a widespread bacterial differentiation program driving antibiotic resistance and virulence in many pathogens. Here, we studied the spatiotemporal localization dynamics of the key regulators that master the two intertwined and transient transcription waves defining competence in Streptococcus pneumoniae. The first wave relies on the stress-inducible phosphorelay between ComD and ComE proteins, and the second on the alternative sigma factor σX, which directs the expression of the DprA protein that turns off competence through interaction with phosphorylated ComE. We found that ComD, σX and DprA stably co-localize at one pole in competent cells, with σX physically conveying DprA next to ComD. Through this polar DprA targeting function, σX mediates the timely shut-off of the pneumococcal competence cycle, preserving cell fitness. Altogether, this study unveils an unprecedented role for a transcription σ factor in spatially coordinating the negative feedback loop of its own genetic circuit.
All data generated or analysed during this study are included in the manuscript and supporting files.
- Patrice Polard
- Patrice Polard
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- Melanie Blokesch, Ecole Polytechnique Fédérale de Lausanne, Switzerland
© 2020, Johnston et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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