HetL, HetR and PatS form a reaction-diffusion system to control pattern formation in the cyanobacterium Nostoc PCC 7120
- Aix-Marseille University-CNRS, France
- Aix-Marseille university-CNRS, France
- Institut de Microbiologie de la Méditerranée, CNRS, France
- Aix-Marseille university, CNRS, France
- Universite de Lorraine, Inra, France
Abstract
Local activation and long-range inhibition are mechanisms conserved in self-organizing systems leading to biological patterns. A number of them involve the production by the developing cell of an inhibitory morphogen, but how this cell becomes immune to self-inhibition is rather unknown. Under combined nitrogen starvation, the multicellular cyanobacterium Nostoc PCC 7120 develops nitrogen-fixing heterocysts with a pattern of one heterocyst every 10-12 vegetative cells. Cell differentiation is regulated by HetR which activates the synthesis of its own inhibitory morphogens, diffusion of which establishes the differentiation pattern. Here we show that HetR interacts with HetL at the same interface as PatS, and that this interaction is necessary to suppress inhibition and to differentiate heterocysts. hetL expression is induced under nitrogen-starvation and is activated by HetR, suggesting that HetL provides immunity to the heterocyst. This protective mechanism might be conserved in other differentiating cyanobacteria as HetL homologues are spread across the phylum.
Data availability
All data generated or analysed during this study are included in the manuscript and supporting files. Source data files are provided for bacterial two hybrid analysis, qRT-PCR and heterocyst intervals and percentages
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Funding
Centre National de la Recherche Scientifique
- Xiaomei Xu
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2020, Xu 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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HetL, HetR and PatS form a reaction-diffusion system to control pattern formation in the cyanobacterium Nostoc PCC 7120
eLife 9:e59190.
https://doi.org/10.7554/eLife.59190
