DYNAREP: Illuminating the dynamics of eukaryotic replication on DNA and chromatin

The copying of DNA, or DNA replication, is essential to cellular function. In eukaryotes it is carried out with high fidelity by a multiprotein complex called the replisome. Failure to do so can lead to defects in the copied genome, slow down or stall the replisome, and result in genomic instability or cell death. Mechanistic insight into normal replisome functioning is a prerequisite for understanding such failure and its downstream consequences.

This is an exciting time in eukaryotic DNA replication, as advances in genetics, biochemistry, and structural biology have identified the essential replisome components together with their stable arrangements. However, in operation the replisome is an active molecular machine with transient parts. Thus, a full mechanistic insight into this molecular machine requires a description of its dynamics.

Because the replisome is active on DNA that is compacted into chromatin, this description must include the duplication and reassembly of all DNA-associated proteins. Understanding the coupling between these processes has fundamental implications for epigenetic inheritance and cancer.

Here, using an integrated approach at the interface of single-molecule biophysics and biochemistry, we will gain a biophysical understanding of the operation of an individual eukaryotic replisome by examining its functioning on DNA and chromatin:

We will reveal how the intricate interplay between replisome components differs on DNA and defined chromatin landscapes.

We will dissect the contributions of physical forces and histone chaperoning in establishing proper reassembly of DNA-associated proteins on daughter DNAs. Integrating our findings with biochemical and structural data will yield new models of eukaryotic DNA replication.

This places us in a unique position to make major contributions to the field of eukaryotic DNA replication and provide it with powerful biophysical tools to investigate both fundamental and biomedically targeted questions.