Brucella abortus Cell Cycle and Infection Are Coordinated

Brucellae are facultative intracellular pathogens. The recent development of methods and genetically engineered strains allowed the description of cell-cycle progression of Brucella abortus, including unipolar growth and the ordered initiation of chromosomal replication. B. abortus cell-cycle progression is coordinated with intracellular trafficking in the endosomal compartments. Bacteria are first blocked at the G1 stage, growth and chromosome replication being resumed shortly before reaching the intracellular proliferation compartment. The control mechanisms of cell cycle are similar to those reported for the bacterium Caulobacter crescentus, and they are crucial for survival in the host cell. The development of single-cell analyses could also be applied to other bacterial pathogens to investigate their cell-cycle progression during infection.

TrendsBrucella abortus is a facultative intracellular pathogen that grows unipolarly and initiates the replication of its two chromosomes in a specific order.Bacteria at the G1 stage of the cell cycle, that is, before the initiation of their chromosomal replication, are preferentially internalized in host cells.Cell-cycle progression is coordinated with trafficking in the host cell, the endosomal stage being divided into two parts: a first, long, nongrowing part, and a second part in which growth and chromosomal replication are resumed.A cell-cycle control network, conserved with the model bacterium Caulobacter crescentus, is essential for B. abortus virulence.