Format

Send to

Choose Destination
Curr Biol. 2011 Jul 12;21(13):1092-101. doi: 10.1016/j.cub.2011.05.040. Epub 2011 Jun 16.

Modularity of the bacterial cell cycle enables independent spatial and temporal control of DNA replication.

Author information

1
Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.

Abstract

BACKGROUND:

Complex regulatory circuits in biology are often built of simpler subcircuits or modules. In most cases, the functional consequences and evolutionary origins of modularity remain poorly defined.

RESULTS:

Here, by combining single-cell microscopy with genetic approaches, we demonstrate that two separable modules independently govern the temporal and spatial control of DNA replication in the asymmetrically dividing bacterium Caulobacter crescentus. DNA replication control involves DnaA, which promotes initiation, and CtrA, which silences initiation. We show that oscillations in DnaA activity dictate the periodicity of replication while CtrA governs the asymmetric replicative fates of daughter cells. Importantly, we demonstrate that DnaA activity oscillates independently of CtrA.

CONCLUSIONS:

The genetic separability of spatial and temporal control modules in Caulobacter reflects their evolutionary history. DnaA is the central component of an ancient and phylogenetically widespread circuit that governs replication periodicity in Caulobacter and most other bacteria. By contrast, CtrA, which is found only in the asymmetrically dividing α-proteobacteria, was integrated later in evolution to enforce replicative asymmetry on daughter cells.

PMID:
21683595
PMCID:
PMC3143580
DOI:
10.1016/j.cub.2011.05.040
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Elsevier Science Icon for PubMed Central
Loading ...
Support Center