Who's in charge here? Regulating cell cycle regulators

Recent studies have illuminated key features of the transcriptional and signal transduction networks governing the cell division cycle of Caulobacter crescentus. These mechanisms generate oscillations in the activity of CtrA, a key regulator of DNA replication and transcription of cell cycle regulated genes. ctrA transcription is itself regulated as part of a cascade of transcriptional regulators, each of which drives the synthesis of proteins needed at different stages of the cell cycle. The CtrA protein is post-transcriptionally regulated by an extended network of two-component signaling proteins and by proteolysis. Proteins within these pathways are localized at opposite ends of the cell to generate two progenies in different stages of the cell cycle upon cell division.