Abstract
In Caulobacter crescentus the combined action of chromosome replication and the expression of DNA methyl-transferase CcrM at the end of S-phase maintains a cyclic alternation between a full- to hemi-methylated chromosome. This transition of the chromosomal methylation pattern affects the DNA-binding properties of the transcription factor GcrA that controls the several key cell cycle functions. However, the molecular mechanism by which GcrA and methylation are linked to transcription is not fully elucidated yet. Using a combination of cell biology, genetics, and in vitro analysis, we deciphered how GcrA integrates the methylation pattern of several S-phase expressed genes to their transcriptional output. We demonstrated in vitro that transcription of ctrA from the P1 promoter in its hemi-methylated state is activated by GcrA, while in its fully methylated state GcrA had no effect. Further, GcrA and methylation together influence a peculiar distribution of creS transcripts, encoding for crescentin, the protein responsible for the characteristic shape of Caulobacter cells. This gene is duplicated at the onset of chromosome replication and the two hemi-methylated copies are spatially segregated. Our results indicated that GcrA transcribed only the copy where coding strand is methylated. In vitro transcription assay further substantiated this finding. As several of the cell cycle-regulated genes are also under the influence of methylation and GcrA-dependent transcriptional regulation, this could be a mechanism responsible for maintaining the gene transcription dosage during the S-phase.
| Original language | English |
|---|---|
| Pages (from-to) | 127-139 |
| Number of pages | 13 |
| Journal | Molecular Microbiology |
| Volume | 114 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 1 Jul 2020 |
Bibliographical note
Funding Information:This work was supported by the financial assistance from the Agence Nationale de la Recherche (contract: ANR 11 JSV3 003 01, CASTACC), the University of Lille 1 (Villeneuve d’Ascq, France), the Region Nord‐Pas de Calais, and the CNRS, France. The authors also thank Michael Laub, Patrick Viollier, Sunish Radhakrishnan, and R. Roberts for some of the strains and plasmids used in the study. Authors have no conflict of interest to declare.
Funding Information:
This work was supported by the financial assistance from the Agence Nationale de la Recherche (contract: ANR 11 JSV3 003 01, CASTACC), the University of Lille 1 (Villeneuve d?Ascq, France), the Region Nord-Pas de Calais, and the CNRS, France. The authors also thank Michael Laub, Patrick Viollier, Sunish Radhakrishnan, and R. Roberts for some of the strains and plasmids used in the study. Authors have no conflict of interest to declare.
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© 2020 John Wiley & Sons Ltd
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