Complete genome sequence of Caulobacter crescentus

The complete genome sequence of Caulobacter crescentus was determined to be 4,016,942 base pairs in a single circular chromosome encoding 3,767 genes. This organism, which grows in a dilute aquatic environment coordinates the cell division cycle and multiple cell differentiation events. With the ann otated genome sequence, a full description of the genetic network that cont rols bacterial differentiation, cell growth, and cell cycle progression is within reach. Two-component signal transduction proteins are known to play a significant role in cell cycle progression. Genome analysis revealed that the C. crescentus genome encodes a significantly higher number of these si gnaling proteins (105) than any bacterial genome sequenced thus far. Anothe r regulatory mechanism involved in cell cycle progression is DNA methylatio n. The occurrence of the recognition sequence for an essential DNA methylat ing enzyme that is required for cell cycle regulation is severely limited a nd shows a bias to intergenic regions. The genome contains multiple cluster s of genes encoding proteins essential for survival in a nutrient poor habi tat. Included are those involved in chemotaxis, outer membrane channel func tion, degradation of aromatic ring compounds, and the breakdown of plant-de rived carbon sources, in addition to many extracytoplasmic function sigma f actors, providing the organism with the ability to respond to a wide range of environmental fluctuations. C. crescentus is, to our knowledge, the firs t free-living alpha -class proteobacterium to be sequenced and will serve a s a foundation for exploring the biology of this group of bacteria, which i ncludes the obligate endosymbiont and human pathogen Rickettsia prowazekii, the plant pathogen Agrobacterium tumefaciens, and the bovine and human pat hogen Brucella abortus.