Systems biology of Caulobacter

The dynamic range of a bacterial species' natural environment is reflected in the complexity of its systems that control cell cycle progression and its range of adaptive responses. We discuss the genetic network and integrated three-dimensional sensor/response systems that regulate the cell cycle and asymmetric cell division in the bacterium Caulobacter crescentus. The cell cycle control circuitry is tied closely to chromosome replication and morphogenesis by multiple feedback pathways from the modular functions that implement the cell cycle. The sophistication of the genetic regulatory circuits and the elegant integration of temporally controlled transcription and protein synthesis with spatially dynamic phosphosignaling and proteolysis pathways, and epigenetic regulatory mechanisms, form a remarkably robust living system.