Abstract 1546 Last stop on the road to repair: Nick sealing by DNA ligase 1 and 3

Base excision repair (BER), a major system for averting the harmful effects of endogenous and environmental toxicant-induced DNA damage, requires a tight coordination at the downstream steps involving gap filling by DNA polymerase (pol) β and subsequent nick sealing by DNA ligase (LIG) 1 and 3α. Our biochemical studies defined the key molecular determinants of uncoordinated repair pathway in case of polβ inserting mismatches, oxidized nucleotides or ribonucleotides leading to ligase failure and formation of deleterious DNA intermediates.