Complex genetic interactions between DNA polymerase β and the NHEJ ligase.

Mammalian cells possess multiple pathways for repairing various types of DNA damage. Although the molecular mechanisms of each DNA repair pathway have been analyzed by biochemical analysis and cell biological analysis, interplay between different pathways has not been fully elucidated. In this study, using human Nalm-6-mutant cell lines, we analyzed the relationship between the base excision repair factor DNA polymerase β (POLβ) and DNA ligase IV (LIG4), which is essential for DNA double-strand break (DSB) repair by non-homologous end-joining (NHEJ).