Multiple links connect central carbon metabolism to DNA replication initiation and elongation in Bacillus subtilis.

DNA replication is coupled to growth by an unknown mechanism. Here, we investigated this coupling by analyzing growth and replication in 15 mutants of central carbon metabolism (CCM) cultivated in three rich media. In about one-fourth of the condition tested, defects in replication resulting from changes in initiation or elongation were detected.

SeqA structures behind Escherichia coli replication forks affect replication elongation and restart mechanisms.

The SeqA protein binds hemi-methylated GATC sites and forms structures that sequester newly replicated origins and trail the replication forks. Cells that lack SeqA display signs of replication fork disintegration. The broken forks could arise because of over-initiation (the launching of too many forks) or lack of dynamic SeqA structures trailing the forks.

Lack of the H-NS Protein Results in Extended and Aberrantly Positioned DNA during Chromosome Replication and Segregation in Escherichia coli.

Unlabelled: The architectural protein H-NS binds nonspecifically to hundreds of sites throughout the chromosome and can multimerize to stiffen segments of DNA as well as to form DNA-protein-DNA bridges. H-NS has been suggested to contribute to the orderly folding of the Escherichia coli chromosome in the highly compacted nucleoid. In this study, we investigated the positioning and dynamics of the origins, the replisomes, and the SeqA structures trailing the replication forks in cells lacking the H-NS protein.

The DnaA Protein Is Not the Limiting Factor for Initiation of Replication in Escherichia coli.

The bacterial replication cycle is driven by the DnaA protein which cycles between the active ATP-bound form and the inactive ADP-bound form. It has been suggested that DnaA also is the main controller of initiation frequency. Initiation is thought to occur when enough ATP-DnaA has accumulated.

Dynamic Escherichia coli SeqA complexes organize the newly replicated DNA at a considerable distance from the replisome.

The Escherichia coli SeqA protein binds to newly replicated, hemimethylated DNA behind replication forks and forms structures consisting of several hundred SeqA molecules bound to about 100 kb of DNA. It has been suggested that SeqA structures either direct the new sister DNA molecules away from each other or constitute a spacer that keeps the sisters together. We have developed an image analysis script that automatically measures the distance between neighboring foci in cells.

Escherichia coli SeqA structures relocalize abruptly upon termination of origin sequestration during multifork DNA replication.

The Escherichia coli SeqA protein forms complexes with new, hemimethylated DNA behind replication forks and is important for successful replication during rapid growth. Here, E. coli cells with two simultaneously replicating chromosomes (multifork DNA replication) and YFP tagged SeqA protein was studied.

Depletion of acidic phospholipids influences chromosomal replication in Escherichia coli.

In Escherichia coli, coordinated activation and deactivation of DnaA allows for proper timing of the initiation of chromosomal synthesis at the origin of replication (oriC) and assures initiation occurs once per cell cycle. In vitro, acidic phospholipids reactivate DnaA, and in vivo depletion of acidic phospholipids, results in growth arrest. Growth can be restored by the expression of a mutant form of DnaA, DnaA(L366K), or by oriC-independent DNA synthesis, suggesting acidic phospholipids are required for DnaA- and oriC-dependent replication.