TY - JOUR
T1 - Molecular basis for DNA double-strand break annealing and primer extension by an NHEJ DNA polymerase
AU - Brissett, Nigel
PY - 2013/11/14
Y1 - 2013/11/14
N2 - Nonhomologous end-joining (NHEJ) is one of the major DNA double-strand break (DSB) repair pathways. The mechanisms by which breaks are competently brought together and extended during NHEJ is poorly understood. As polymerases extend DNA in a 5'-3' direction by nucleotide addition to a primer, it is unclear how NHEJ polymerases fill in break termini containing 3' overhangs that lack a primer strand. Here, we describe, at the molecular level, how prokaryotic NHEJ polymerases configure a primer-template substrate by annealing the 3' overhanging strands from opposing breaks, forming a gapped intermediate that can be extended in trans. We identify structural elements that facilitate docking of the 3' ends in the active sites of adjacent polymerases and reveal how the termini act as primers for extension of the annealed break, thus explaining how such DSBs are extended in trans. This study clarifies how polymerases couple break-synapsis to catalysis, providing a molecular mechanism to explain how primer extension is achieved on DNA breaks.
AB - Nonhomologous end-joining (NHEJ) is one of the major DNA double-strand break (DSB) repair pathways. The mechanisms by which breaks are competently brought together and extended during NHEJ is poorly understood. As polymerases extend DNA in a 5'-3' direction by nucleotide addition to a primer, it is unclear how NHEJ polymerases fill in break termini containing 3' overhangs that lack a primer strand. Here, we describe, at the molecular level, how prokaryotic NHEJ polymerases configure a primer-template substrate by annealing the 3' overhanging strands from opposing breaks, forming a gapped intermediate that can be extended in trans. We identify structural elements that facilitate docking of the 3' ends in the active sites of adjacent polymerases and reveal how the termini act as primers for extension of the annealed break, thus explaining how such DSBs are extended in trans. This study clarifies how polymerases couple break-synapsis to catalysis, providing a molecular mechanism to explain how primer extension is achieved on DNA breaks.
UR - https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/24239356/?tool=EBI
U2 - 10.1016/j.celrep.2013.10.016
DO - 10.1016/j.celrep.2013.10.016
M3 - Article
C2 - 24239356
SN - 2211-1247
JO - Cell Reports
JF - Cell Reports
ER -