700 Million Years of Eating DNA:
A Conserved Competence Regulon in Gamma-Proteobacteria.
Dr. Andrew Cameron
University of British Columbia, Vancouver, B.C.
Tuesday, March 6th, at 4:30 – 5:30 p.m.
Ruhl Student Center, Community Room
Many bacteria use natural competence to take up foreign DNA from their environment, but why do they do it? Does the DNA serve primarily as a source of novel genes or is it used as a source of nutrients? Studying gene regulation in the model bacterium Haemophilus influenzae helps to answer these questions because regulatory mechanisms evolve to respond to the needs of the cell. In H. influenzae, natural competence genes are tightly regulated by two transcription factors, CRP and Sxy. CRP is a very well-characterized activator of the cell’s global sugar starvation response; however, we have discovered an entirely novel mode of regulation in which Sxy enables CRP to activate transcription at a new class of CRP sites in competence gene promoters. Comparative genomics and gene expression assays revealed that the same mechanism regulates competence genes in some of the best studied bacterial species, including E. coli, Salmonella, and Vibrio cholerae. We have also found that Sxy expression responds to nucleotide pools, strongly suggesting that many bacteria inhabiting disparate environments regulate genes for DNA uptake according to nutritional signals.
Andrew received his B.Sc. in Biology from Malaspina University-College in Nanaimo, British Columbia, Canada, in 2000. While an undergraduate student, Andrew worked on two undergraduate research projects. One with Dr. Allen Gibson on the role of myc protein in cell growth regulation, and a second while the Neotropical Biology Fellow, at University-College of Belize, in Belize Central America, where he studies microbial water quality in th eBelize River and specific the detection of Vibrio cholerae O1. Andrew is currently a member of the Department of Microbiology at the University of British Columbia. He will soon defend his doctoral thesis and then move to Spain to conduct post-doctoral work studying the evolutionary and engineering potential of gene regulatory networks.