Survey of Genomes - Caulobacter crescentus
Tim Stucky takes us away from the human microbiome out into nature, specifically clean freshwater habitats with very few nutrients. He discusses the genome of Caulobacter crescentus, a stalked bacterium that can either swim or attached itself to a substrate.
Caulobacter is tightly regulated in how it can only replicate its DNA one time while in the stalk phase. It will replicate its single chromosome and divide into two more swarmer cells. In the C. crescentus 4,016,942 base pair genome, there are 3767 genes averaging 969 base pairs in size. There are 3763 proteins thought to be produced by the genome with 1012 being hypothetical and 2751 having matches to known proteins. This genome has the largest ratio of signal transduction proteins made to any other bacteria that has been fully sequenced. This has allowed researchers to test and gain a much deeper understanding of these pathways and how they are used in regulating the cycles of development. Researchers have also found that there were 13 undiscovered RNA Polymerase sigma factors made in C. crescentus. Sigma factors help regulate changes in gene expression by coupling with outside stimuli. This has significance in the organism’s development and has allowed deeper research into gene expression. The last point of importance is that it initiates replication in different ways depending on the media it grows on. This has allowed researchers to study in depth, how cells adapt and change their replication control based on the nutrients provided to them.
This bacteria has been vital in cell cycle research and has provided insight and discovery since its discovery in the 1930’s. Thanks for joining me and I hope you enjoyed learning about Caulobacter crescentus and its contributions to genetics.
Gorbatyuk, B., & Marczynski, G. T. (2004, December 09). Regulated degradation of chromosome replication proteins DnaA and CtrA in Caulobacter crescentus. Retrieved from https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2958.2004.04459.x
Nierman, W. C., Feldblyum, T. V., Laub, M. T., Paulsen, I. T., Nelson, K. E., Eisen, J., . . . Fraser, C. M. (2001, March 27). Complete genome sequence of Caulobacter crescentus. Retrieved from https://www.pnas.org/content/98/7/4136.short
POINDEXTER, J. S. (1964, September). BIOLOGICAL PROPERTIES AND CLASSIFICATION OF THE CAULOBACTER GROUP. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC441226/?page=2
Toh, E., Kurtz, H. D., & Brun, Y. V. (2008, November 01). Characterization of the Caulobacter crescentus Holdfast Polysaccharide Biosynthesis Pathway Reveals Significant Redundancy in the Initiating Glycosyltransferase and Polymerase Steps. Retrieved from https://jb.asm.org/content/190/21/7219.short