Working Paper Article Version 1 This version is not peer-reviewed

Inactivation of Three RG(S/T)GR Pentapeptide—Containing Negative Regulators of HetR Results in Lethal Differentiation of Anabaena PCC 7120

Version 1 : Received: 31 October 2020 / Approved: 2 November 2020 / Online: 2 November 2020 (15:32:02 CET)

How to cite: Khudyakov, I.; Gladkov, G.; Elhai, J. Inactivation of Three RG(S/T)GR Pentapeptide—Containing Negative Regulators of HetR Results in Lethal Differentiation of Anabaena PCC 7120. Preprints 2020, 2020110059 Khudyakov, I.; Gladkov, G.; Elhai, J. Inactivation of Three RG(S/T)GR Pentapeptide—Containing Negative Regulators of HetR Results in Lethal Differentiation of Anabaena PCC 7120. Preprints 2020, 2020110059

Abstract

The filamentous cyanobacterium Anabaena sp. PCC 7120 expresses during the differentiation of heterocysts a short peptide PatS and a protein HetN, both containing an RGSGR pentapeptide essential for activity. Both act on the master regulator HetR to guide heterocyst pattern formation by controlling the binding of HetR to DNA and its turnover. A third small protein, PatX, with an RG(S/T)GR motif is present in all HetR-containing cyanobacteria. In nitrogen-depleted medium, inactivation of patX does not produce a discernible change in phenotype, but its overexpression blocks heterocyst formation. Mutational analysis revealed that PatX is not required for normal intercellular signaling, but it nonetheless is required when PatS is absent to prevent rapid ectopic differentiation. Deprivation of all three negative regulators – PatS, PatX, and HetN – resulted in synchronous differentiation. However, in nitrogen-containing medium, such deprivation leads to extensive fragmentation, cell lysis, and aberrant differentiation, while either PatX or PatS as the sole HetR regulator can establish and maintain a semiregular heterocyst pattern. These results suggest that tight control over HetR by PatS and PatX is needed to sustain vegetative growth and regulated development. The mutational analysis has been interpreted in light of the opposing roles of negative regulators of HetR and the positive regulator HetL. Keywords: cyanobacteria; heterocyst, regulation of differentiation

Subject Areas

cyanobacteria; heterocyst; regulation of differentiation

Comments (0)

We encourage comments and feedback from a broad range of readers. See criteria for comments and our diversity statement.

Leave a public comment
Send a private comment to the author(s)
Views 0
Downloads 0
Comments 0
Metrics 0


×
Alerts
Notify me about updates to this article or when a peer-reviewed version is published.
We use cookies on our website to ensure you get the best experience.
Read more about our cookies here.