Medical Sciences
Building, #4182
1 King's College Circle
Toronto, Ontario
M5S 1A8
(416) 978-1665
b.funnell@utoronto.ca
My lab is interested in the mechanisms of chromosome segregation, and in particular the segregation of a bacterial plasmid called P1. The process of segregation, or "partition", is coordinated with DNA replication, with the cell cycle, and with cell division. P1 plasmid partition is a model for the complex processes that segregate cellular as well as plasmid chromosomes. P1 plasmid maintenance in Escherichia coli serves as a simple nonpathogenic model for the maintenance of many naturally occurring plasmids in pathogenic bacteria; transmission and maintenance of such plasmids in bacterial populations contribute significantly to the rapid spread of antibiotic resistance and virulence among pathogenic bacterial species.
Partition is a reaction that positions the plasmids at specific locations inside the cell. P1 uses a number of plasmid- and host-encoded proteins to promote this localization. Using a combination of molecular biology, genetics, biochemistry and cell biology, we are studying the activity of the plasmid-encoded proteins, called ParA and ParB, and are searching for bacterial factors required for this process. We can, for example (in the photo below), monitor the position of the plasmids by immunofluorescent staining of ParB, a site-specific DNA binding protein that binds to P1 DNA. The ParA protein is an ATPase, which likely provides the energy to drive the positioning process. ParA- and ParB-like proteins have been identified as components of the plasmid and chromosomal segregation machinery of a variety of bacterial species. Our goals are to understand how proper segregation is achieved and regulated in the cell cycle.
ParB protein, as red (Cy3) dots or foci, marks the location of P1 plasmids (see Erdmann et al, 1999).
Vecchiarelli, A.G, Schumacher, M.A. and Funnell, B.E. (2007) Assembly of P1 partition complexes involves multiple modes of protein-DNA recognition, J. Biol. Chem. 282:10944-10952.
Schumacher, M.A. and Funnell, B.E. (2005). ParB-DNA structures reveal DNA-binding mechanism of partition complex formation. Nature 438:516-519.
Slavcev, R.A. and Funnell, B.E. (2005). Identification and characterization of a novel allele of E. coli dnaB helicase that compromises the stability of plasmid P1. J. Bacteriol. 187:1227-1237.
Funnell, B.E. (2005). Partition-mediated plasmid pairing. Plasmid 53:119-125.
Funnell, B.E. and Phillips, G.J., editors, (2004). “Plasmid Biology”, ASM Press, Washington , D.C. , 614 p.
Funnell, B.E. and R.A. Slavcev (2004). Partition systems of bacterial plasmids. In Funnell, B.E. and Phillips, G.J., editors, “Plasmid Biology”, ASM Press, Washington , D.C. , pp. 81-103.
Surtees, J.A. and B.E. Funnell (2003). Plasmid and chromosome traffic control: How ParA and ParB drive partition. Curr. Topics Develop. Biol. 56: 145-180.
Fung, E.,
Bouet, J-Y. and B.E. Funnell (2001). Probing the ATP binding site of P1 ParA:
Partition and repression have different requirements for ATP binding and hydrolysis.
EMBO J. 20: 4901-4911.
Surtees, J.A. and B.E. Funnell (2001). The DNA-binding domains of P1 ParB and
the architecture of the P1 plasmid partition complex. J. Biol. Chem.
276: 12385-12394.
Bouet, J.-Y., Surtees, J.A. and B.E. Funnell (2000). Stoichiometry of P1 plasmid
partition complexes. J. Biol. Chem. 275: 8213-8219.
Erdmann, N., Petroff, T. and B.E. Funnell (1999). Intracellular localization of P1 ParB protein is dependent on ParA and parS. Proc. Natl. Acad. Sci. USA 96: 14905-14910.
Surtees, J.A. and B.E. Funnell (1999). P1 ParB domain structure includes two independent multimerization domains. J. Bacteriol. 181: 5898-5908.
Bouet, J.-Y. and B.E. Funnell (1999). P1 ParA interacts with the P1 partition complex at parS and an ATP-ADP switch controls ParA activities. EMBO J. 18: 1415-1424.
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