Research Groups > DNA Replication

DNA is the blueprint of life and makes biological existence possible. Cells have the extraordinary capability to reproduce, by duplicating their DNA, which enables DNA segregation and cell division. DNA replication is a mammoth task, requiring assembly of large 50+ protein machine on an origin DNA to generate two precise copies of the DNA. The study of this remarkable machine is a challenge, but also a great opportunity to understand a fundamental process.
 

Figure 1. ORC-Cdc6 complex formation on origin DNA visualised by DNAsel footprint

During DNA replication, proteins recognise the origin of replication and load the replicative helicase onto DNA, which unzips the two strands of DNA. During the G1-S transition, kinases signal directly and indirectly to the helicase to start DNA replication. In consequence the helicase produces ss-DNA, which can be copied by the polymerase. There still many mysteries about the DNA replication machinery and its regulation to solve.

We have recently reconstituted the loading of the eukaryotic helicase onto DNA, an essential step in DNA replication and are now able to use this system to address the mechanism and regulation of two key events: the loading of the eukaryotic DNA helicase onto DNA and the kinase dependent activation of the helicase. Furthermore, we will start to assemble a eukaryotic replication fork to analyse its organisation and the functions of its components. We use Saccharomyces cerevisiae for our work, which is an excellent model organism, since all the important replication proteins are conserved between yeast and humans. This work will help us to recognise how replication errors involved in tumorigenesis occur and to identify future therapeutic targets.

Figure 2. Regulated formation of the ORC-Cdc6-DNA complex