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Direct single-cell observation of a key Escherichia coli cell-cycle oscillator.

ABSTRACT: Initiation of DNA replication in Escherichia coli is coupled to cell size via the DnaA protein, whose activity is dependent on its nucleotide-bound state. However, the oscillations in DnaA activity have never been observed at the single-cell level. By measuring the volume-specific production rate of a reporter protein under control of a DnaA-regulated promoter, we could distinguish two distinct cell-cycle oscillators. The first, driven by both DnaA activity and SeqA repression, shows a causal relationship with cell size and divisions, similarly to initiation events. The second one, a reporter of DnaA activity alone, loses the synchrony and causality properties. Our results show that transient inhibition of gene expression by SeqA keeps the oscillation of volume-sensing DnaA activity in phase with the subsequent division event and suggest that DnaA activity peaks do not correspond directly to initiation events.

SUBMITTER: Iuliani I

PROVIDER: S-EPMC466948 | biostudies-literature | 2024 Jul

REPOSITORIES: biostudies-literature

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Direct single-cell observation of a key <i>Escherichia coli</i> cell-cycle oscillator.

Iuliani Ilaria I Mbemba Gladys G Lagomarsino Marco Cosentino MC Sclavi Bianca B

Science advances 20240717 29

Initiation of DNA replication in <i>Escherichia coli</i> is coupled to cell size via the DnaA protein, whose activity is dependent on its nucleotide-bound state. However, the oscillations in DnaA activity have never been observed at the single-cell level. By measuring the volume-specific production rate of a reporter protein under control of a DnaA-regulated promoter, we could distinguish two distinct cell-cycle oscillators. The first, driven by both DnaA activity and SeqA repression, shows a ca ...[more]

PMID: 39018394

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