The essential elements for the noncovalent association of two DNA ends during NHEJ synapsis

Zhao, Bailin; Watanabe, Go; Morten, Michael J.; Reid, Dylan A.; Rothenberg, Eli; Lieber, Michael R.

doi:10.1038/s41467-019-11507-z

Cited by 82 publications

(83 citation statements)

References 43 publications

(67 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is suggested that DNA‐PKcs is not required for the formation of either FS or CS. This latter model explains the evolutionarily central synaptic role of the core NHEJ factors, Ku70, Ku80, XRCC4, Lig4 and XLF 24 …”

Section: Introductionmentioning

confidence: 91%

“…PAXX and MRI have not been implicated in this model because their functions have not been identified 7 . Another model proposed by Lieber’s group 24 suggests that there are two major structural complexes formed during the NHEJ synapsis. Ku70, Ku80, XRCC4 and Lig4 form the flexible synaptic (FS) complex, where XRCC4 and Lig4 bind to each DSB through interaction of Lig4 with Ku heterodimer.…”

Section: Introductionmentioning

confidence: 93%

See 1 more Smart Citation

Genetic interaction between the non‐homologous end‐joining factors during B and T lymphocyte development: In vivo mouse models

et al. 2020

View full text Add to dashboard Cite

DNA double-strand breaks (DSBs) are generated both extrinsically, for example, by chemotherapeutic agents, and physiologically, for example, during V(D)J recombination in developing B and T lymphocytes, and class switch recombination (CSR) in activated mature B cells. 1,2 The DNA damage response (DDR) pathway is initiated upon the induction of DSBs. Ataxia telangiectasia mutated (ATM) is a DDR regulator protein kinase that phosphorylates

show abstract

Section: Introductionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 93%

Genetic interaction between the non‐homologous end‐joining factors during B and T lymphocyte development: In vivo mouse models

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Furthermore, recent work in a human reconstitution of NHEJ also suggest that XLF filaments are not necessary for end synapsis. 37 Therefore, we considered a model in which the two tails of the XLF dimer enable the formation of a Ku-XLF-Ku bridge 33 that is required to synapse DNA ends. Using synthetic tandem dimers of XLF, we generated asymmetric XLF dimers to show that a single KBM within an XLF dimer is sufficient to promote NHEJ in both Xenopus egg extract (FIG 4B-C) and in mammalian cells (FIG 6B).…”

Section: Recruitment Of Xlf To Dsbs Is Necessary But Not Sufficient Fmentioning

confidence: 99%

XLF acts as a flexible connector during non-homologous end joining

Carney

Moreno

Piatt

et al. 2020

Preprint

View full text Add to dashboard Cite

Non-homologous end joining (NHEJ) is the predominant pathway that repairs DNA double strand breaks in vertebrates. During NHEJ DNA ends are held together by a multi-protein synaptic complex until they are ligated. Here we investigate the role of the intrinsically disordered C-terminal tail of XLF, a critical factor in end synapsis. We demonstrate that the XLF tail along with the Ku binding motif (KBM) at the extreme C-terminus are required for end joining. While the underlying sequence of the tail can be varied, a minimal tail length is required for NHEJ. Single-molecule FRET experiments that observe end synapsis in real-time show that this defect is due to a failure to closely align DNA ends. Our data supports a model in which a single C-terminal tail tethers XLF to Ku while allowing XLF to form interactions with XRCC4 that enable synaptic complex formation.

show abstract

“…There are several potential explanations for this unanticipated observation. First, recent findings suggest that DNA-PK may be dispensable for synapsis formation during NHEJ 37 . Accordingly, repair of “simple” DSBs in G1 phase may have a reduced reliance on DNA-PK, whereas repair of more “complex” DSBs in S phase may require DNA-PK, possibly in partnership with the nuclease Artemis 38–40 .…”

Section: Discussionmentioning

confidence: 99%

Hyperactive end joining repair mediates resistance to DNA damaging therapy in p53-deficient cells

Kumar

Chao

Roberts

et al. 2020

Preprint

View full text Add to dashboard Cite

33TP53 mutations in cancer are associated with poor patient outcomes and resistance to 34 DNA damaging therapies 1-3 . However, the mechanisms underlying treatment resistance 35 in p53-deficient cells remain poorly characterized. Here, we show that p53-deficient 36 cells exhibit hyperactive repair of therapy-induced DNA double strand breaks (DSBs), 37 which is suppressed by inhibition of DNA-dependent protein kinase (DNA-PK). Single-38 cell analyses of DSB repair kinetics and cell cycle state transitions reveal an essential 39 role for DNA-PK in suppressing S phase DNA damage and mitotic catastrophe in p53-40 deficient cells. Yet, a subset of p53-deficient cells exhibit intrinsic resistance to 41 therapeutic DSBs due to a repair pathway that is not sensitive to DNA-PK inhibition. 42We show that p53 deficiency induces overexpression of DNA Polymerase Theta (Pol ), 43 which mediates an alternative end-joining repair pathway that becomes hyperactivated 44 by DNA-PK inhibition 4 . Combined inhibition of DNA-PK and Pol  restores therapeutic 45 DNA damage sensitivity in p53-deficient cells. Thus, our study identifies two targetable 46 DSB end joining pathways that can be suppressed as a strategy to overcome resistance 47The mechanisms for therapeutic resistance in p53-deficient cells remains poorly 57 characterized. Past work has suggested a role for loss of p53-mediated apoptosis 12,15 . 58However, the response of epithelial cancer cells to DNA damaging therapy is often 59 determined by the efficiency of inducing senescence or mitotic catastrophe, rather than 60 apoptosis 16,17 . p53 is also a transcription factor that responds to DNA double strand 61 breaks (DSBs) to determine cellular fate 7,18 . Recent insights have revealed the 62 importance of p53-signaling waves in regulation of cellular fate decisions of quiescence 63 versus cell cycle re-entry after DNA damage 19,20 . However, the mechanisms that 64 determine such cell fate decisions upon DNA damage induction in p53-mutant epithelial 65 cells have not been established, and may lead to novel strategies to restore treatment 66 sensitivity. 67In this study, we investigate altered DNA repair mechanisms in p53 deficiency as 68 a major contributor to resistance to DNA damaging therapies. We find that p53-deficient 69 cells exhibit hyperactive repair and accelerated resolution of DNA damage foci. Utilizing 70 live-cell imaging, we show that this ability to resolve DNA damage rapidly is partially 71 dependent on DNA-PK, a critical serine/threonine kinase in the non-homologous end 72 joining (NHEJ) pathway 21 . Inhibition of DNA-PK using the small molecule inhibitor 73 NU7441 partially sensitizes p53-deficient cells to DSB inducing agents. We further show 74 that this effect is specifically due to propagation of S phase related damage leading to 75 mitotic catastrophe, highlighting a role for DNA-PK in S phase DNA damage repair that 76 was previously under appreciated. Furthermore, using chromosomal break repair 77 assays we show that in the context of inhibitor t...

show abstract

The essential elements for the noncovalent association of two DNA ends during NHEJ synapsis

Cited by 82 publications

References 43 publications

Genetic interaction between the non‐homologous end‐joining factors during B and T lymphocyte development: In vivo mouse models

Genetic interaction between the non‐homologous end‐joining factors during B and T lymphocyte development: In vivo mouse models

XLF acts as a flexible connector during non-homologous end joining

Hyperactive end joining repair mediates resistance to DNA damaging therapy in p53-deficient cells

Contact Info

Product

Resources

About