Warsaw breakage syndrome DDX11 helicase acts jointly with RAD17 in the repair of bulky lesions and replication through abasic sites

Abe, Takuya; Ooka, Masato; Kawasumi, Ryotaro; Miyata, Keiji; Takata, Minoru; Hirota, Kouji; Branzei, Dana

doi:10.1073/pnas.1803110115

Cited by 36 publications

(45 citation statements)

References 48 publications

(58 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…DT40 WT BU-1 ΔG4 cells were generated by deleting the +3.5 G4 motif from both alleles of the BU-1 locus 42 . Other mutant lines have also been described previously: fancj 44 , ddx11, fancj/ddx11 and tipin 45,51 .…”

Section: Cell Lines and Transfectionsmentioning

confidence: 99%

Timeless couples G quadruplex detection with processing by DDX11 during DNA replication

Lerner

Holzer

Kilkenny

et al. 2019

Preprint

Self Cite

View full text Add to dashboard Cite

& equal contribution2 Regions of the genome with the potential to form secondary structure pose a frequent and significant impediment to DNA replication and must be actively managed in order to preserve genetic and epigenetic integrity. The fork protection complex (FPC), a conserved group of replisome-associated proteins including Timeless, Tipin, and Claspin, plays an important role in maintaining efficient replisome activation, ensuring optimum fork rates, sister chromatid cohesion and checkpoint function. It also helps maintain the stability of sequences prone to secondary structure formation through an incompletely understood mechanism. Here, we report a previously unappreciated DNA binding domain in the C-terminus of Timeless, which exhibits specific binding to G quadruplex (G4) structures. We show that, in vivo, both the C-terminus of Timeless and the DDX11 helicase act collaboratively to ensure processive replication of G4 structures to prevent genetic and epigenetic instability.DNA can create significant impediments to its own replication through formation of secondary structures. When unwound, certain sequences, often repetitive or of low complexity, can adopt a variety of non-B form structures, including hairpins, cruciforms, triplexes and quadruplexes 1 . It is becoming clear that secondary structure formation is a frequent event during replication, even at genomically abundant sequences previously thought not to be a major source of difficulty 2 . To prevent such sequences causing havoc with the genetic and epigenetic stability of the genome, cells deploy an intricate network of activities to counteract secondary structure formation and limit its effects. These activities include proteins that bind and destabilise DNA structures and specialised helicases that unwind them 3 . In addition, the repriming activity of PrimPol can be deployed to confine a structure into a minimal region of single stranded DNA, limiting the potential dangers of exposing extensive ssDNA in a stalled replisome 2,4 . G quadruplexes (G4s) are one of the most intensively studied and potent structural replication impediments. G4s arise in consequence of the ability of guanine to form Hoogsteen base-paired quartets 5 . In favourable sequence contexts, comprising runs of dG separated by variable numbers of non-G bases, stacks of G quartets form G4s secondary structures. Current estimates suggest that over 700,000 sites in the human genome have the potential to form G4s 6 . While some of these G4s may have important roles in genome physiology, all pose a potential threat to DNA replication and sites with G4-forming potential have been linked to both genetic and epigenetic instability 7,8 .3Precisely how DNA structures are detected and resolved by the replication machinery remains unclear. Many of the factors involved in processing G4 secondary structures, for instance FANCJ and REV1 9-13 , do not appear to be constitutive components of the replisome 14 . It is thus likely that core components of the replisome will act as 'first respo...

show abstract

Section: Cell Lines and Transfectionsmentioning

confidence: 99%

Timeless couples G quadruplex detection with processing by DDX11 during DNA replication

Lerner

Holzer

Kilkenny

et al. 2019

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…A backup pathway for the FA pathway involves the conserved DDX11 helicase and the checkpoint clamp loader RAD17, which act jointly to facilitate recombination-mediated repair of bulky lesions in vertebrate cells [19,20]. In human cells, RAD17 also affects FANCD2 ubiquitylation [48].…”

Section: Smc5/6 Function Is Required For Normal Proliferation In Dt40mentioning

confidence: 99%

“…The FANCD2 monoubiquitylation is important for optimal RAD51 focus formation [49][50][51], and DDX11 deletion in DT40 that does not affect FANCD2 monoubiquitylation also reduces RAD51 focus formation [19]. We assessed the consequences of SMC6 depletion on the formation of RAD51 foci in MMC-or HU-treated HeLa cells.…”

Section: Smc5/6 Acts Jointly With Fancd2 To Mediate Dna Repair and Prmentioning

confidence: 99%

“…smc5 mutant cells showed sensitivity toward DNA intra-and inter-strand crosslinkers (ICLs). Notably, the repair defect of smc5 DT40 cells toward cisplatin was genetically epistatic with mutations in the Fanconi anemia (FA) components, FANCC and FANCM, and with mutations in the FA-like pathway defined by the DNA damage checkpoint clamp loader, RAD17, and the DDX11 helicase [19,20]. Moreover, smc5 mutants were additive to mutations in KU70, mediating non-homologous end-joining (NHEJ) repair of double-strand breaks (DSBs).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

SMC5/6 acts jointly with Fanconi anemia factors to support DNA repair and genome stability

et al. 2019

Self Cite

View full text Add to dashboard Cite

SMC5/6 function in genome integrity remains elusive. Here, we show that SMC5 dysfunction in avian DT40 B cells causes mitotic delay and hypersensitivity toward DNA intra-and inter-strand crosslinkers (ICLs), with smc5 mutants being epistatic to FANCC and FANCM mutations affecting the Fanconi anemia (FA) pathway. Mutations in the checkpoint clamp loader RAD17 and the DNA helicase DDX11, acting in an FA-like pathway, do not aggravate the damage sensitivity caused by SMC5 dysfunction in DT40 cells. SMC5/6 knockdown in HeLa cells causes MMC sensitivity, increases nuclear bridges, micronuclei, and mitotic catastrophes in a manner similar and non-additive to FANCD2 knockdown. In both DT40 and HeLa systems, SMC5/6 deficiency does not affect FANCD2 ubiquitylation and, unlike FANCD2 depletion, RAD51 focus formation. SMC5/6 components further physically interact with FANCD2-I in human cells. Altogether, our data suggest that SMC5/6 functions jointly with the FA pathway to support genome integrity and DNA repair and may be implicated in FA or FA-related human disorders.

show abstract

“…The primary clamp loader in eukaryotes consists of five independent proteins, RFC1 through RFC5. In humans, clamp loaders play a critical role in many diseases such as cancer (Bell et al 2011;von Deimling et al 1999;Li et al 2018), Warsaw Breakage Syndrome (Abe et al 2018), CANVAS disease (Cortese et al 2019), and Hutchinson Gilford Progeria Syndrome (Tang et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Structure of the human clamp loader bound to the sliding clamp: a further twist on AAA+ mechanism

Gaubitz¹,

Liu

Magrino

et al. 2020

Preprint

View full text Add to dashboard Cite

DNA replication requires the sliding clamp, a ring-shaped protein complex that encircles DNA, where it acts as an essential cofactor for DNA polymerases and other proteins. The sliding clamp needs to be actively opened and installed onto DNA by a clamp loader ATPase of the AAA+ family. The human clamp loader Replication Factor C (RFC) and sliding clamp PCNA are both essential and play critical roles in several diseases. Despite decades of study, no structure of human RFC has been resolved. Here, we report the structure of human RFC bound to PCNA by cryo-EM to an overall resolution of ~3.4 Å. The active sites of RFC are fully bound to ATP analogs, which is expected to induce opening of the sliding clamp. However, we observe PCNA in a closed conformation and the clamp loader ATPase modules form an overtwisted spiral that is incapable of binding DNA or hydrolyzing ATP. The autoinhibited conformation observed here has many similarities to a previous yeast RFC:PCNA crystal structure, suggesting that our results are broadly applicable across eukaryotes. We propose a 'crab-claw' mechanism in which PCNA opening is coupled to untwisting of RFC's AAA+ spiral to allow subsequent DNA binding. The proposed change from an overtwisted to an active conformation reveals a novel regulatory mechanism for AAA+ ATPases. Finally, our structural analysis of disease mutations leads to a mechanistic explanation for the role of RFC in human health.

show abstract

Warsaw breakage syndrome DDX11 helicase acts jointly with RAD17 in the repair of bulky lesions and replication through abasic sites

Cited by 36 publications

References 48 publications

Timeless couples G quadruplex detection with processing by DDX11 during DNA replication

Timeless couples G quadruplex detection with processing by DDX11 during DNA replication

SMC5/6 acts jointly with Fanconi anemia factors to support DNA repair and genome stability

Structure of the human clamp loader bound to the sliding clamp: a further twist on AAA+ mechanism

Contact Info

Product

Resources

About