DNA in cells is decorated with methyl and hydroxymethyl marks, which are required for the cell to function. When cells divide, DNA replication dilutes these marks. After replication, these marks must therefore be re-established on DNA. Large regions of the genome commonly lose their DNA methylation in both cancerous and ageing cells. Both cancerous and ageing cells have undergone many cell divisions. This loss may therefore be linked to DNA replication and cell division.
How long it takes to re-establish these marks after DNA replication, and in what manner this happens, is unclear, because the technology required has been unavailable. In this project, I sought to develop new methods capable of addressing these questions and profile how these marks return to their normal levels after being diluted by DNA replication. The novel methods developed in this project can be applied to diverse models to deepen our understanding of DNA modifications in disease states. This work, though not yet finalized, indicates that the rate of cell division outpaces re-establishment of DNA modifications, consistent with the loss of methylation seen after numerous cell divisions in both cancer and ageing. These novel technologies have provided new insights into the links between DNA methylation, DNA replication, and the cell cycle.