DNA ligase 1 (LIG1)

DNA ligase 1 is a nuclear enzyme essential for the final step in joining DNA fragments during both DNA replication and multiple DNA repair processes, including base excision repair, nucleotide excision repair, mismatch repair, and to a lesser extent, non-homologous end joining[1][2][4][6]. It catalyzes the ATP-dependent formation of phosphodiester bonds between adjacent DNA nucleotides, ensuring the integrity and continuity of the genome. In eukaryotic cells, DNA ligase 1 specifically seals nicks between Okazaki fragments during lagging strand synthesis and repairs single-stranded breaks in DNA. Its activity and recruitment are regulated through phosphorylation and interactions with other replication factors such as PCNA. Mutations or dysregulation of DNA ligase 1 are associated with cancer, developmental disorders, and genome instability syndromes, making it a topic of interest for biomarker research and as a potential target for cancer therapeutics, though no specific drugs are in active clinical use yet[2][6].

Other names

DNA ligase ILIG1

Inhibitors of DNA ligase 1 block sealing of DNA nicks, leading to accumulation of DNA breaks, replicative stress, and cell death, especially in rapidly dividing cells or those with increased reliance on LIG1-mediated DNA repair.