Alan R. Davidson

Alan R. Davidson

Professor

BSc, University of Toronto, 1983
PhD, University of Toronto, 1991
Postdoc, Massachusetts Institute of Technology, 1995

Address 1 King's College Circle, Room 4285
Toronto, ON M5S 1A8
Lab Davidson Lab
Lab Phone 416-978-8611
Office Phone 416-978-0332
Email alan.davidson@utoronto.ca

I first discovered the beauty and elegance of phages during my Ph.D. studies, which were focused on the DNA packaging enzyme of E. coli phage lambda. During my post-doctoral work at MIT, I switched to the field of protein structure and folding. I continued this work in my own lab investigating the thermodynamics and kinetics of folding of the SH3 domain. I have also worked extensively on the functioning of SH3 domains in budding yeast. Luckily, as time went on in my own lab, I was able to move back into the phage field.

In the News

Research Lab

My laboratory focuses on elucidating the mechanisms of protein-protein interactions and macromolecular assembly. We study these phenomena in the context of yeast signal transduction pathways and viral morphogenesis. Our phage work utilizes a broad range of approaches, structural biology, in vitro biochemistry, molecular biology, in vivo studies, and bioinformatics. I encourage my students to learn as many approaches as possible during their graduate studies and a major goal of my research program is to provide a fruitful training ground for my students where they can gain experience in as many techniques as possible, and develop independent projects based on their own interests and strengths. I also encourage them to have as much fun as possible.

Learn more: Davidson Lab

Research Description

Bacteriophages

My laboratory focuses on bacteriophages (phages), the viruses that infect bacteria. We are interested in:

  1. How phage particles assemble. For these studies we combine techniques of structural biology (X-ray crystallography, NMR, and electron microscopy) with molecular biology and in vivo studies.
  2. How phage genomes found within bacterial genomes (prophages) alter the physiology of the host bacteria. We pursue this work primarily in the pathogenic bacteria, Pseudomonas aeruginosa. We seek to understand how prophages affect virulence and pathogenesis of this organism. This work is relevant to Cystic Fibrosis patients in whom P. aeruginosa is a major cause of illness.
  3. Phage-related entities encoded in bacterial genomes. These entities, such as R- and F-pyocins in P. aeruginosa or Photorhabdus Virulence Cassettes in other species, can mediate killing of other bacterial species or eukaryotic cells. Little is known of how these entities function.
  4. CRISPR-Cas systems. CRISPR-Cas systems are an adaptive immunity system in bacteria. They operate in a manner similar to RNAi in eukaryotes and are widespread in both bacteria and archaea. Recently CRISPR-Cas systems have been adapted for genome editing in a wide variety of species including humans. We discovered phage-encoded genes that inhibit the CRISPR-Cas systems of P. aeruginosa, and we are currently studying the prevalence of these anti-CRISPR systems and how they work.

A major goal of my research program is to provide a fruitful training ground for my students where they can gain experience in as many techniques as possible, and develop independent projects based on their own interests and strengths.

Publications

A new group of phage anti-CRISPR genes inhibits the type I-E CRISPR-Cas system of Pseudomonas aeruginosa
Pawluk A, Bondy-Denomy J, Cheung VH, Maxwell KL, Davidson AR.
MBio 25, e00896 (2014)  Read

HNH proteins are a widespread component of phage DNA packaging machines
Kala S, Cumby N, Sadowski PD, Hyder BZ, Kanelis V, Davidson AR, Maxwell KL
Proc Natl Acad Sci U S A. 111, 6022-6027 (2014)  Read

Bacteriophage genes that inactivate the CRISPR/Cas bacterial immune system
Bondy-Denomy, J., Pawluk, A., Maxwell, K.L. & Davidson, A.R.
Nature 493, 429–432 (2013)  Read

Structural and functional studies of gpX of Escherichia coli phage P2 reveal a widespread role for LysM domains in the baseplates of contractile-tailed phages
Maxwell KL, Fatehi Hassanabad M, Chang T, Paul VD, Pirani N, Bona D, Edwards AM, Davidson AR
J Bacteriol. 195, 5461-5468 (2013)  Read

Tail tip proteins related to bacteriophage λ gpL coordinate an iron-sulphur cluster
Tam, W., Pell, L.G., Bona, D., Tsai1, A., Dai, X.X., Hendrix, R.W., Maxwell, K.L., and Davidson, A.R.
J. Mol. Biol. 425, 2450–2462 (2013)  Read

The CRISPR/Cas Adaptive Immune System of Pseudomonas aeruginosa Mediates Resistance to Naturally Occurring and Engineered Phages
Cady, K.C., Bondy-Denomy, J., Heussler, G.E., Davidson, A.R. & O'Toole, G.A.
J Bacteriol. 194, 5728-5738 (2012)  Read

Assembly mechanism is the key determinant of the dosage sensitivity of a phage structural protein.
Cardarelli. L., Maxwell, K.L., Davidson, A.R.
Proc Natl Acad Sci U S A 108, 10168-10173 (2011)  Read

Phages have adapted the same protein fold to fulfill multiple functions in virion assembly
Cardarelli, L., Pell, L.G., Neudecker, P., Pirani, N., Liu, A., Baker, L.A., Rubinstein, J.L., Maxwell, K.L., Davidson, A.R.
Proc Natl Acad Sci U S A 107, 14384-14389 (2010)  Read

The phage λ major tail protein structure reveals a common evolution for long-tailed phages and the type VI bacterial secretion system
Pell, L.G., Kanelis, V., Donaldson, L.W., Howell, P.L., Davidson, A.R.
Proc Natl Acad Sci U S A 106, 4160-4165 (2009)  Read