We are using evolution as a tool to dissect the molecular interactions underpinning the process of DNA replication. To achieve this we are exploiting the observation that during evolution, three principal phylogenetic Domains have appeared: Bacteria, Archaea and Eucarya. While the molecular machineries for the processes of DNA replication and transcription are fundamentally related between archaea and eukaryotes, the archaeal apparatus is in essence a stripped down version of that in eukaryotes. This simplicity, coupled with the conservation of the processes, render archaea a biochemically tractable, high-resolution model for the human DNA replication machinery.
The primary focus of my lab's research is the DNA replication machinery of hyperthermophilic archaeon Sulfolobus solfataricus. It is our aim to elucidate the biochemical basis of the mechanisms that underpin the initiation and elongation phases of DNA replication and to identify the conserved interaction interfaces between components of the machinery. To do this we have cloned, expressed and purified the Sulfolobus DNA replication proteins and identified origins of replication on the Sulfolobus chromosome. Using a combination of biochemical and molecular biological methods we have begun to determine the mode of action of these proteins and investigate their interactions both with each other and with the DNA template. We are now applying our findings to the human replication system.