XLF-Cernunnos_Riballo_et_al.pdf (744.34 kB)
XLF-Cernunnos promotes DNA ligase IV-XRCC4 re-adenylation following ligation
journal contribution
posted on 2023-06-07, 15:11 authored by Enriqueta Riballo, Lisa Woodbine, Thomas StiffThomas Stiff, Sarah A. Walker, Aaron A. Goodarzi, Penny JeggoXLF-Cernunnos (XLF) is a component of the DNA ligase IV-XRCC4 (LX) complex, which functions during DNA non-homologous end joining (NHEJ). Here, we use biochemical and cellular approaches to probe the impact of XLF on LX activities. We show that XLF stimulates adenylation of LX complexes de-adenylated by pyrophosphate or following LX decharging during ligation. XLF enhances LX ligation activity in an ATP-independent and dependent manner. ATP-independent stimulation can be attributed to enhanced end-bridging. Whilst ATP alone fails to stimulate LX ligation activity, addition of XLF and ATP promotes ligation in a manner consistent with XLF-stimulated readenylation linked to ligation. We show that XLF is a weakly bound partner of the tightly associated LX complex and, unlike XRCC4, is dispensable for LX stability. 2BN cells, which have little, if any, residual XLF activity, show a 3-fold decreased ability to repair DNA double strand breaks covering a range of complexity. These findings strongly suggest that XLF is not essential for NHEJ but promotes LX adenylation and hence ligation. We propose a model in which XLF, by in situ recharging DNA ligase IV after the first ligation event, promotes double stranded ligation by a single LX complex.
History
Publication status
- Published
File Version
- Accepted version
Journal
Nucleic Acids ResearchISSN
0305-1048Publisher
Oxford University PressPublisher URL
External DOI
Issue
2Volume
37Page range
482-492Department affiliated with
- Sussex Centre for Genome Damage Stability Publications
Notes
GDSC282Full text available
- Yes
Peer reviewed?
- Yes