Format

Send to

Choose Destination
Mol Cell. 2019 Dec 12. pii: S1097-2765(19)30866-4. doi: 10.1016/j.molcel.2019.11.018. [Epub ahead of print]

A Mechanism to Minimize Errors during Non-homologous End Joining.

Author information

1
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
2
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Boston, MA 02115, USA. Electronic address: johannes_walter@hms.harvard.edu.
3
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA. Electronic address: joseph_loparo@hms.harvard.edu.

Abstract

Enzymatic processing of DNA underlies all DNA repair, yet inappropriate DNA processing must be avoided. In vertebrates, double-strand breaks are repaired predominantly by non-homologous end joining (NHEJ), which directly ligates DNA ends. NHEJ has the potential to be highly mutagenic because it uses DNA polymerases, nucleases, and other enzymes that modify incompatible DNA ends to allow their ligation. Using frog egg extracts that recapitulate NHEJ, we show that end processing requires the formation of a "short-range synaptic complex" in which DNA ends are closely aligned in a ligation-competent state. Furthermore, single-molecule imaging directly demonstrates that processing occurs within the short-range complex. This confinement of end processing to a ligation-competent complex ensures that DNA ends undergo ligation as soon as they become compatible, thereby minimizing mutagenesis. Our results illustrate how the coordination of enzymatic catalysis with higher-order structural organization of substrate maximizes the fidelity of DNA repair.

KEYWORDS:

NHEJ; end processing; non-homologous end joining; single-molecule; smFRET

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center