A cartoon of a section of chromatin in the nucleus with replication origins in three different states.

John Diffley : DNA replication mechanisms, regulation and misregulation in cancer

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We use biochemical approaches with purified proteins and cell biology to understand the mechanism of MCM helicase assembly and activation and the mechanism of replisome progression, normally and in response to DNA damage. We also use cell biology in human cells to understand how DNA replication is regulated, and how its misregulation might contribute to cancer biology.

We have reconstituted the initiation of DNA replication with purified proteins. We will use this system to understand how the MCM replicative helicase is activated and how this leads to assembly of the replisome. We will also use this system to understand how DNA replication interfaces with chromatin assembly and RNA transcription, how DNA damage is sensed by the replisome, how DNA damage checkpoints regulate replisome progression, how specific regions of the genome (e.g. telomeres, heterochromatin) are replicated and how DNA replication interacts with many other nuclear processes.

We use biochemistry, cell biology and genetics to understand how DNA replication is regulated in human cells, and how it is misregulated in cancer. We are interested in how oncogenes deregulate DNA replication, and how misregulation of the cell cycle and DNA damage checkpoints might contribute to genome instability and drug resistance in cancer.

 A simplified view of eukaryotic DNA replication origin firing

Figure 1: A simplified view of eukaryotic DNA replication origin firing, with an emphasis on current interests of the Diffley Lab