Non-histone chromatin proteins: much more than a barrier to DNA repair

GASTON SORIA

Sao Pablo

Congreso; V FARM DNA meeting; 2013

USP

The view of DNA packaging into chromatin as a mere obstacle for DNA repair is evolving. In this talk I will discuss the case of heterochromatin protein 1 paralogs (HP1α, β and γ in mammals), which besides being central in heterochromatin organization, have also been linked recently to the DNA damage response (DDR). I will discuss how HP1 proteins contribute to the DDR at a molecular level, and whether HP1 paralogs within the same organism, as well as their respective orthologs, have overlapping or unique roles in the DDR. The experimental work I will show combines the analysis of the efficiency and kinetics of recruitment of key repair proteins to sites of DNA damage with specific DNA repair assays to demonstrate that human HP1 paralogs differentially modulate homology-directed repair (HDR) pathways, including homologous recombination (HR) and single-strand annealing (SSA). I will finalize my talk discussing this emerging role of HP1 proteins as active players in the DDR, putting such findings in perspective with recent reports describing similar active roles for other non-histone chromatin proteins.