Faculty Opinions recommendation of The Werner syndrome RECQ helicase targets G4 DNA in human cells to modulate transcription.

SummaryFunctional genomics approaches can overcome current limitations that hamper oncology drug development such as lack of robust target identification and clinical efficacy. Here we performed genome-scale CRISPR-Cas9 screens in 204 human cancer cell lines from 12 cancer-types and developed a data-driven framework to prioritise cancer therapeutic candidates. We integrated gene cell fitness effects with genomic biomarkers and target tractability for drug development to systematically prioritise new oncology targets in defined tissues and genotypes. Furthermore, we took one of our most promising dependencies, Werner syndrome RecQ helicase, and verified it as a candidate target for tumours with microsatellite instability. Our analysis provides a comprehensive resource of cancer dependencies, a framework to prioritise oncology targets, and nominates specific new candidates. The principles described in this study can transform the initial stages of the drug development process contributing to a new, diverse and more effective portfolio of oncology targets.

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Functional conservation of RecQ helicase BLM between humans and Drosophila melanogaster

Scientific Reports ◽

10.1038/s41598-019-54101-5 ◽

2019 ◽

Vol 9 (1) ◽

Author(s):

Rebecca L. Cox ◽

Carolyn M. Hofley ◽

Pallavi Tatapudy ◽

Romil K. Patel ◽

Yaron Dayani ◽

...

Keyword(s):

Drosophila Melanogaster ◽

Werner Syndrome ◽

Genetic Diseases ◽

Strand Break ◽

Bloom Syndrome ◽

Recq Helicase ◽

Recq Helicases ◽

Functional Conservation ◽

Increased Sensitivity ◽

Inherited Mutations

AbstractRecQ helicases are a family of proteins involved in maintaining genome integrity with functions in DNA repair, recombination, and replication. The human RecQ helicase family consists of five helicases: BLM, WRN, RECQL, RECQL4, and RECQL5. Inherited mutations in RecQ helicases result in Bloom Syndrome (BLM mutation), Werner Syndrome (WRN mutation), Rothmund-Thomson Syndrome (RECQL4 mutation), and other genetic diseases, including cancer. The RecQ helicase family is evolutionarily conserved, as Drosophila melanogaster have three family members: DmBlm, DmRecQL4, and DmRecQL5 and DmWRNexo, which contains a conserved exonuclease domain. DmBlm has functional similarities to human BLM (hBLM) as mutants demonstrate increased sensitivity to ionizing radiation (IR) and a decrease in DNA double-strand break (DSB) repair. To determine the extent of functional conservation of RecQ helicases, hBLM was expressed in Drosophila using the GAL4 > UASp system to determine if GAL4 > UASp::hBLM can rescue DmBlm mutant sensitivity to IR. hBLM was able to rescue female DmBlm mutant sensitivity to IR, supporting functional conservation. This functional conservation is specific to BLM, as human GAL4 > UASp::RECQL was not able to rescue DmBlm mutant sensitivity to IR. These results demonstrate the conserved role of BLM in maintaining the genome while reinforcing the applicability of using Drosophila as a model system to study Bloom Syndrome.

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Action-at-a-Distance Mutagenesis Induced by Oxidized Guanine in Werner Syndrome Protein-Reduced Human Cells

Chemical Research in Toxicology ◽

10.1021/tx500418m ◽

2015 ◽

Vol 28 (4) ◽

pp. 621-628 ◽

Cited By ~ 7

Author(s):

Hiroyuki Kamiya ◽

Daiki Yamazaki ◽

Eri Nakamura ◽

Tetsuaki Makino ◽

Miwako Kobayashi ◽

...

Keyword(s):

Werner Syndrome ◽

Human Cells ◽

Werner Syndrome Protein ◽

Action At A Distance ◽

Oxidized Guanine ◽

Syndrome Protein

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Functional role of the Werner syndrome RecQ helicase in human fibroblasts

Aging Cell ◽

10.1111/j.1474-9726.2006.00260.x ◽

2007 ◽

Vol 6 (1) ◽

pp. 53-61 ◽

Cited By ~ 41

Author(s):

Kiranjit K. Dhillon ◽

Julia Sidorova ◽

Yannick Saintigny ◽

Martin Poot ◽

Katherine Gollahon ◽

...

Keyword(s):

Functional Role ◽

Werner Syndrome ◽

Human Fibroblasts ◽

Recq Helicase

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Residues in the RecQ C-terminal Domain of the Human Werner Syndrome Helicase Are Involved in Unwinding G-quadruplex DNA

Journal of Biological Chemistry ◽

10.1074/jbc.m116.767699 ◽

2017 ◽

Vol 292 (8) ◽

pp. 3154-3163 ◽

Cited By ~ 10

Author(s):

Amit Ketkar ◽

Markus Voehler ◽

Tresor Mukiza ◽

Robert L. Eoff

Keyword(s):

Werner Syndrome ◽

Nmr Studies ◽

Quadruplex Dna ◽

G4 Dna ◽

G Quadruplex ◽

Preferential Binding ◽

Werner Syndrome Protein ◽

Efficient Processing ◽

Significant Block ◽

Syndrome Protein

The structural and biophysical properties typically associated with G-quadruplex (G4) structures render them a significant block for DNA replication, which must be overcome for cell division to occur. The Werner syndrome protein (WRN) is a RecQ family helicase that has been implicated in the efficient processing of G4 DNA structures. The aim of this study was to identify the residues of WRN involved in the binding and ATPase-driven unwinding of G4 DNA. Using a c-Myc G4 DNA model sequence and recombinant WRN, we have determined that the RecQ-C-terminal (RQC) domain of WRN imparts a 2-fold preference for binding to G4 DNA relative to non-G4 DNA substrates. NMR studies identified residues involved specifically in interactions with G4 DNA. Three of the amino acids in the WRN RQC domain that exhibited the largest G4-specific changes in NMR signal were then mutated alone or in combination. Mutating individual residues implicated in G4 binding had a modest effect on WRN binding to DNA, decreasing the preference for G4 substrates by ∼25%. Mutating two G4-interacting residues (T1024G and T1086G) abrogated preferential binding of WRN to G4 DNA. Very modest decreases in G4 DNA-stimulated ATPase activity were observed for the mutant enzymes. Most strikingly, G4 unwinding by WRN was inhibited ∼50% for all three point mutants and >90% for the WRN double mutant (T1024G/T1086G) relative to normal B-form dsDNA substrates. Our work has helped to identify residues in the WRN RQC domain that are involved specifically in the interaction with G4 DNA.

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BLM helicase facilitates telomere replication during leading strand synthesis of telomeres

The Journal of Cell Biology ◽

10.1083/jcb.201410061 ◽

2015 ◽

Vol 210 (2) ◽

pp. 191-208 ◽

Cited By ~ 63

Author(s):

William C. Drosopoulos ◽

Settapong T. Kosiyatrakul ◽

Carl L. Schildkraut

Keyword(s):

Single Molecule ◽

Werner Syndrome ◽

Telomeric Dna ◽

G4 Dna ◽

Genome Wide ◽

Blm Helicase ◽

Telomere Replication ◽

Leading Strand ◽

Single Molecule Analysis

Based on its in vitro unwinding activity on G-quadruplex (G4) DNA, the Bloom syndrome–associated helicase BLM is proposed to participate in telomere replication by aiding fork progression through G-rich telomeric DNA. Single molecule analysis of replicated DNA (SMARD) was used to determine the contribution of BLM helicase to telomere replication. In BLM-deficient cells, replication forks initiating from origins within the telomere, which copy the G-rich strand by leading strand synthesis, moved slower through the telomere compared with the adjacent subtelomere. Fork progression through the telomere was further slowed in the presence of a G4 stabilizer. Using a G4-specific antibody, we found that deficiency of BLM, or another G4-unwinding helicase, the Werner syndrome-associated helicase WRN, resulted in increased G4 structures in cells. Importantly, deficiency of either helicase led to greater increases in G4 DNA detected in the telomere compared with G4 seen genome-wide. Collectively, our findings are consistent with BLM helicase facilitating telomere replication by resolving G4 structures formed during copying of the G-rich strand by leading strand synthesis.

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