Profile

Career

Research

Overview

Research interests focus on the molecular mechanisms and dynamics of procaryotic DNA segregation. Multidrug resistance plasmids harbour their own survival system, a partition cassette, which ensures an accurate and equitable segregation of the plasmids from one generation to the next at cell division. When this system malfunctions, the plasmid is not stably inherited and is ultimately lost. The multidrug resistance plasmid TP228 replicates at low copy number in Escherichia coli. The partition cassette (~1,100 bp) of TP228 consists of the parFG genes and upstream noncoding sequence ( parH ) which harbours a series of related direct and invert repeat motifs. We have recently shown that ParF is an ATPase that assembles into extensive, multistranded filaments in vitro. The partner partition protein ParG plays at least two distinct roles in ParF polymerization dynamics: 1) it enhances ParF ATPase activity and 2) it promotes filament bundling. The recently acquired data allowed us to propose a mitotic spindle-like molecular mechanism for plasmid segregation in E. coli. Investigations are also underway to study the molecular mechanisms of genome segregation in the archaeon Sulfolobus.

Discoveries

The finding that the ATPase activity of ParF is stimulated by the partition protein ParG via an arginine finger-like mechanism analogous to that of eukaryotic RasGAPs.

Current projects

• A minimalist mitotic spindle driving chromosome segregation in Archaea (The Leverhulme Trust)
• Structure-function analysis of the DNA segregation factor ParG (ORS)
• Assembly dynamics of the DNA partition protein ParF (BBSRC)

Research group(s)

Available PhD research projects

Targeting a bacterial mitotic spindle to combat antibiotic resistance (for 2012-13)

Bacterial multidrug resistance is a global burden on human health worldwide. Large, low copy number plasmids, implicated in antibiotic resistance, have evolved sophisticated strategies to ensure their faithful distribution at cell division. Multidrug resistance plasmids harbour their own survival system, a partition cassette, which ensures an accurate and equitable segregation of the plasmids from one generation to the next at cell division. When this system malfunctions, the plasmid is not stably inherited and is ultimately lost. The multidrug resistance plasmid TP228 replicates at low copy number in Escherichia coli. The partition cassette (~1,100 bp) of TP228 consists of the parFG genes and upstream noncoding sequence (parH) which harbours a series of related direct and invert repeat motifs. We have shown that ParF is an ATPase that assembles into extensive, multistranded filaments in vitro. The partner partition protein ParG plays at least two distinct roles in ParF polymerization dynamics: 1) it enhances ParF ATPase activity and 2) it promotes filament bundling. The recently acquired data allowed us to propose a mitotic spindle-like molecular mechanism for plasmid segregation in E. coli. This project will investigate the molecular mechanism of ParF polymerization and how ParF polymers drive DNA segregation at cell division. The study will involve molecular biology, biochemical and biophysical approaches in parallel with fluorescence microscopy to visualize DNA positioning, trafficking and segregation in the cell.

Publications

Selected publications

• Dobruk-Serkowska A, Caccamo M, Rodriguez-Castañeda F, Wu M, Bryce K, Ng I, Schumacher MA, Barillà D, Hayes F (2012) Uncoupling of nucleotide hydrolysis and polymerization in the ParA protein superfamily disrupts DNA segregation dynamics. J Biol Chem 287: 42545-42553.
• Knappy CS, Barillà D, de Blaquiere JP, Morgan HW, Nunn CE, Suleman M, Tan CH, Keely BJ. (2012) Structural complexity in isoprenoid glycerol dialkyl glycerol tetraether lipid cores of Sulfolobus and other archaea revealed by liquid chromatography-tandem mass spectrometry. Chem Phys Lipids 165: 648-655.
• Schumacher MA, Ye Q, Barge MT, Zampini M, Barillà D, Hayes F (2012) Structural mechanism of ATP induced polymerization of the partition factor ParF: implications for DNA segregation.  J Biol Chem 287: 26146-26154.
• Sanford-Kalliomaa AK, Rodriguez-Castañeda F, McLeod BN, Latorre-Rosellò V, Smith JH, Reimann J, Albers S-V, Barillà D (2012) Chromosome segregation in Archaea mediated by a hybrid DNA partition machine. Proc Natl Acad Sci USA 109: 3754-3759.
• Barillà D (2010) One-way ticket to the cell pole: plasmid transport by the prokaryotic tubulin homolog TubZ. Proc Natl Acad Sci USA 107: 12061-12062.
• Hayes F, Barillà D (2010) Extrachromosomal components of the nucleoid: recent developments in deciphering the molecular basis of plasmid segregation. In CJ Dorman and RT Dame (ed.), Bacterial Chromatin, Springer, The Netherlands, pp. 49-70.
• Derome A, Hoischen C, Bussiek M, Grady R, Adamczyk M, Kedzierska B, Diekmann S, Barillà D, Hayes F (2008) Centromere anatomy in the multidrug resistant pathogen Enterococcus faecium. Proc Natl Acad Sci USA 105: 2151-2156.

External activities

Memberships

• Member of the Society for General Microbiology  
• Member of the Biochemical Society                                  
• Member of the American Society for Microbiology
• Member of the BBSRC Research Committee Pool