Precise timing of transcription by c-di-GMP coordinates cell cycle and morphogenesis in Caulobacter

Andreas Kaczmarczyk,Urs Jenal,Raphael Böhm,Christoph Von Arx,Antje M Hempel,Sebastian Hiller,Jutta Nesper,Badri N Dubey,Tilman Schirmer

doi:10.1038/s41467-020-14585-6

Andreas Kaczmarczyk, Urs Jenal + Show 7 more

Open Access

https://doi.org/10.1038/s41467-020-14585-6

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Journal: Nature Communications	Publication Date: Feb 10, 2020
Citations: 41	License type: open-access

Affiliation: University of Basel

Abstract

Bacteria adapt their growth rate to their metabolic status and environmental conditions by modulating the length of their G1 period. Here we demonstrate that a gradual increase in the concentration of the second messenger c-di-GMP determines precise gene expression during G1/S transition in Caulobacter crescentus. We show that c-di-GMP stimulates the kinase ShkA by binding to its central pseudo-receiver domain, activates the TacA transcription factor, and initiates a G1/S-specific transcription program leading to cell morphogenesis and S-phase entry. Activation of the ShkA-dependent genetic program causes c-di-GMP to reach peak levels, which triggers S-phase entry and promotes proteolysis of ShkA and TacA. Thus, a gradual increase of c-di-GMP results in precise control of ShkA-TacA activity, enabling G1/S-specific gene expression that coordinates cell cycle and morphogenesis.

Highlights

Bacteria adapt their growth rate to their metabolic status and environmental conditions by modulating the length of their G1 period
A C. crescentus strain lacking all diguanylate cyclases, which was generated to remove all traces of the second messenger c-di-GMP, shows strong developmental and morphological abnormalities with mutant cells being irregularly shaped, elongated and lacking all polar appendages[11]
Expression of TacAD54E, a phospho-mimetic form of TacA13, restored stalk biogenesis, transcription of the TacA targets staR and spmX, as well as localization of a SpmX-mCherry fusion to the stalked pole (Fig. 1c, d; Supplementary Fig. 1). spmX and staR transcription was restored when c-di-GMP was reintroduced by expression of the heterologous diguanylate cyclase (DGC) dgcZ from E. coli in the cdG0 background or in a strain that lacks all DGCs and phosphodiesterases (PDE) (Fig. 1d; Supplementary Fig. 1)

Summary

Introduction

Bacteria adapt their growth rate to their metabolic status and environmental conditions by modulating the length of their G1 period. We show that c-di-GMP stimulates the kinase ShkA by binding to its central pseudo-receiver domain, activates the TacA transcription factor, and initiates a G1/S-specific transcription program leading to cell morphogenesis and S-phase entry. A gradual increase of c-di-GMP results in precise control of ShkA-TacA activity, enabling G1/Sspecific gene expression that coordinates cell cycle and morphogenesis. Activation of DivK and PleD is directed by the SpmX scaffolding protein, which accumulates during G1/S and recruits DivJ, the kinase of DivK and PleD, to the incipient stalked cell pole (Fig. 1a)[12] This makes SpmX accumulation the earliest known event to trigger S-phase entry. TacA controls a large set of target genes including staR, which encodes a transcription factor important for stalk elongation This phosphorelay system coordinates replication initiation with morphogenesis. The exact timing of G1/S-specific gene expression results from the consecutive c-di-GMP-mediated activation and degradation of ShkATacA phosphorylation components

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