CELL CYCLE-DEPENDENT POLAR LOCALIZATION OF CHROMOSOME PARTITIONING PROTEINS IN CAULOBACTER-CRESCENTUS

In the bacterium C. crescentus, the cellular homologs of plasmid parti tioning proteins, ParA and ParB, localize to both poles of the predivi sional cell following the completion of DNA replication. pare binds to DNA sequences adjacent to the origin of replication suggesting that t his region of the genome is tethered to the poles of the cell at a spe cific time in the cell cycle. Increasing the cellular levels of ParA a nd ParB disrupts polar localization and results in defects in both cel l division and chromosome partitioning. These results suggest that Par A and ParB are involved in partitioning newly replicated chromosomes t o the poles of the predivisional cell and may function as components o f a bacterial mitotic apparatus.