In all organisms, repairing DNA damage is critical to maintaining genomic integrity and therefore viability. Indeed, the loss of chromosomal stability is coincident with the development of many cancer-related diseases. The process of replication fork restart, following fork stalling or collapse, is central to the maintenance of normal genetic equilibrium.
My group aims to examine mechanisms of DNA repair and replication fork restart by taking advantage of the experimental tractability of model archaeal species from the genus Sulfolobus. These extraordinary hyperthermophilic microbes thrive at temperatures of around 80°C, and at pH as low as 2. Importantly, components of the archaeal DNA repair and replication machinery display functional homology to their eukaryotic counterparts, indicating that basic eukaryotic-like processes can be observed in these experimentally amenable organisms. By investigating the clear archaeal orthologues of eukaryotic repair proteins, the general themes observed in this laboratory will aid our comprehension of eukaryotic DNA replication-associated repair processes.
Advantages of archaeal models:
1. The intrinsic thermostability of extremophilic archaeal proteins renders the Sulfolobus system particularly suitable to biochemical and structural analysis.
2. Components of the archaeal replication and repair apparatus display functional homology to their eukaryotic counterparts.
3. Several archaeal species, including Sulfolobus, utilise multiple origins of replication, a situation comparable to eukaryotic replication.
4. Due to the extreme environment in which Sulfolobus grows, DNA repair will be a constant and observable feature of the cell cycle.
5. Genetic tools are now available to manipulate hyperthermophilic archaea
We are especially interested in the DNA-end resection process required for homologous recombination during DNA double-strand break repair. Thermophilic archaea utilise a minimal end-resection apparatus consisting of the highly conserved Mre11-Rad50 complex and the HerA-NurA translocase-nuclease machinery. We are also interested in the involvement of archaeal Urm1/SAMP ubiquitin-like modifications in the regulation of protein homeostasis and degradation by the proteasome. Further details can be found by following the links below.
This work is supported by the Medical Research Council, and the Isaac Newton Trust.
Lab members: Salman Anjum, John Blackwood, Sian Bray
1. Anjum, R.S.*, Bray, S.M.*, Blackwood, J.K., Kilkenny, M.L., Coelho, M.A., Foster, B.M., Li, S., Howard, J.A., Pellegrini, L., Albers, S.V., Deery, M.J., and Robinson, N.P. 2015. Involvement of a eukaryotic-like ubiquitin-related modifier in the proteasome pathway of the archaeon Sulfolobus acidocaldarius. Nature Communications. 2015. DOI: 10.1038/ncomm9163.
2. Rzechorzek, N.J., Blackwood, J.K., Bray, S.M., Maman, J.D., Pellegrini, L., and Robinson, N.P. 2014. Structure of the hexameric HerA ATPase reveals a mechanism of translocation-coupled DNA-end processing in archaea. Nature Communications. 2014. DOI: 10.1038/ncomm6506.
3. Blackwood, J.K., Rzechorzek, N.J., Bray, S.M., Maman, J.D., Pellegrini, L., and Robinson, N.P. 2013. End Resection at DNA Double-Strand Breaks in the Three Domains of Life. Biochemical Society Transactions. 2013. 41 (1):314-20.
4. Blackwood, J.K.*, Rzechorzek, N.J.*, Abrams, A.S., Maman, J.D., Pellegrini, L., and Robinson, N.P. 2011. Structural and functional insights into DNA-end processing by the archaeal HerA helicase- NurA nuclease complex. Nucleic Acids Research. 2012. 40 (7):3183-96.
5. Robinson, N. P., and S. D. Bell. 2007. Extrachromosomal element capture and the evolution of multiple replication origins in archaeal chromosomes. Proc Natl Acad Sci U S A 104:5806-11.
6. Robinson, N. P., K. A. Blood, S. A. McCallum, P. A. Edwards, and S. D. Bell. 2007. Sister chromatid junctions in the hyperthermophilic archaeon Sulfolobus solfataricus. EMBO J. 2007. 26:816-24.
7. Robinson, N. P., I. Dionne, M. Lundgren, V. L. Marsh, R. Bernander, and S. D. Bell. 2004. Identification of two origins of replication in the single chromosome of the archaeon Sulfolobus solfataricus. Cell. 2004. 116:25-38.