Accurate chromosomal DNA replication is of fundamental importance for cellular function, genome integrity and development. In response to replication perturbations, DNA damage response (DDR) and DNA damage tolerance (DDT) pathways become activated and are crucial for detection and tolerance of lesions, as well as for replication completion and chromosome structural integrity. While important functions and key players of these regulatory processes have been outlined, much less is known about the choreography and mechanistic interplay between DDR and DDT. Moreover, the principles by which they uniquely or commonly affect replication-associated chromosome integrity remain poorly understood.
We plan to use a palette of ingenious genetic, molecular and proteomic based experimental strategies, to address three main topics. We will define the principles of local and temporal regulation of DDT in response to genotoxic stress, with a focus on the mechanisms of SUMO-regulated DNA metabolism processes. Additionally, we will investigate the topological DNA transitions triggered at intrinsically difficult to replicate genomic regions, stalled and terminal forks, with the aim of identifying key mechanisms and regulators of replication integrity at specific complex genomic regions or following specific types of replication stress. Finally, we will explore the relationship between DDT, replication fork architecture and sister chromatid cohesion in the context of DDR- and SUMO-orchestrated DNA transactions.