scholarly journals Uncovering an allosteric mode of action for a selective inhibitor of human Bloom syndrome protein

2020 ◽  
Author(s):  
X. Chen ◽  
Y. Ali ◽  
C.E.L. Fisher ◽  
R. Arribas-Bosacoma ◽  
M.B. Rajasekaran ◽  
...  
Keyword(s):  
Synthetic Lethality ◽  
Specific Inhibitor ◽  
Bloom Syndrome ◽  
Dna Helicase ◽  
Holliday Junctions ◽  
Dna Structures ◽  
Recq Helicases ◽  
Promising Target ◽  
Opening And Closing ◽  
Syndrome Protein

ABSTRACTBLM (Bloom syndrome protein) is a RECQ-family helicase involved in the dissolution of complex DNA structures and repair intermediates. Synthetic lethality analysis implicates BLM as a promising target in a range of cancers with defects in the DNA damage response, however selective small molecule inhibitors of defined mechanism are currently lacking. Here we identify and characterise a specific inhibitor of BLM’s ATPase-coupled DNA helicase activity, by allosteric trapping of a DNA-bound translocation intermediate. Crystallographic structures of BLM-DNA-ADP-inhibitor complexes identify a hitherto unknown interdomain interface, whose opening and closing are integral to translocation of ssDNA, and which provides a highly selective pocket for drug discovery. Comparison with structures of other RECQ helicases provides a model for branch migration of Holliday junctions by BLM.

scholarly journals Uncovering an allosteric mode of action for a selective inhibitor of human Bloom syndrome protein

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Xiangrong Chen ◽  
Yusuf I Ali ◽  
Charlotte EL Fisher ◽  
Raquel Arribas-Bosacoma ◽  
Mohan B Rajasekaran ◽  
...  
Keyword(s):  
Synthetic Lethality ◽  
Specific Inhibitor ◽  
Bloom Syndrome ◽  
Dna Helicase ◽  
Holliday Junctions ◽  
Dna Structures ◽  
Recq Helicases ◽  
Promising Target ◽  
Opening And Closing ◽  
Syndrome Protein

BLM (Bloom syndrome protein) is a RECQ-family helicase involved in the dissolution of complex DNA structures and repair intermediates. Synthetic lethality analysis implicates BLM as a promising target in a range of cancers with defects in the DNA damage response; however, selective small molecule inhibitors of defined mechanism are currently lacking. Here, we identify and characterise a specific inhibitor of BLM’s ATPase-coupled DNA helicase activity, by allosteric trapping of a DNA-bound translocation intermediate. Crystallographic structures of BLM-DNA-ADP-inhibitor complexes identify a hitherto unknown interdomain interface, whose opening and closing are integral to translocation of ssDNA, and which provides a highly selective pocket for drug discovery. Comparison with structures of other RECQ helicases provides a model for branch migration of Holliday junctions by BLM.

scholarly journals Removal of the Bloom Syndrome DNA Helicase Extends the Utility of Imprecise Transposon Excision for Making Null Mutations in Drosophila

Genetics ◽  
2009 ◽  
Vol 183 (3) ◽  
pp. 1187-1193 ◽  
Author(s):  
Alice Witsell ◽  
Daniel P. Kane ◽  
Sarah Rubin ◽  
Mitch McVey
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Elements ◽  
Bloom Syndrome ◽  
Dna Helicase ◽  
Imprecise Excision ◽  
Syndrome Protein

Transposable elements are frequently used in Drosophila melanogaster for imprecise excision screens to delete genes of interest. However, these screens are highly variable in the number and size of deletions that are recovered. Here, we show that conducting excision screens in mus309 mutant flies that lack DmBlm, the Drosophila ortholog of the Bloom syndrome protein, increases the percentage and overall size of flanking deletions recovered after excision of either P or Minos elements.

scholarly journals DisA Limits RecG Activities at Stalled or Reversed Replication Forks

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1357
Author(s):  
Rubén Torres ◽  
Carolina Gándara ◽  
Begoña Carrasco ◽  
Ignacio Baquedano ◽  
Silvia Ayora ◽  
...  
Keyword(s):  
Atp Hydrolysis ◽  
Holliday Junctions ◽  
Genome Integrity ◽  
Stable Complex ◽  
Dna Unwinding ◽  
Replication Forks ◽  
Dna Structures ◽  
Checkpoint Protein

The DNA damage checkpoint protein DisA and the branch migration translocase RecG are implicated in the preservation of genome integrity in reviving haploid Bacillus subtilis spores. DisA synthesizes the essential cyclic 3′, 5′-diadenosine monophosphate (c‑di-AMP) second messenger and such synthesis is suppressed upon replication perturbation. In vitro, c-di-AMP synthesis is suppressed when DisA binds DNA structures that mimic stalled or reversed forks (gapped forks or Holliday junctions [HJ]). RecG, which does not form a stable complex with DisA, unwinds branched intermediates, and in the presence of a limiting ATP concentration and HJ DNA, it blocks DisA-mediated c-di-AMP synthesis. DisA pre-bound to a stalled or reversed fork limits RecG-mediated ATP hydrolysis and DNA unwinding, but not if RecG is pre-bound to stalled or reversed forks. We propose that RecG-mediated fork remodeling is a genuine in vivo activity, and that DisA, as a molecular switch, limits RecG-mediated fork reversal and fork restoration. DisA and RecG might provide more time to process perturbed forks, avoiding genome breakage.

scholarly journals The Bloom syndrome complex senses RPA-coated single-stranded DNA to restart stalled replication forks

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ann-Marie K. Shorrocks ◽  
Samuel E. Jones ◽  
Kaima Tsukada ◽  
Carl A. Morrow ◽  
Zoulikha Belblidia ◽  
...  
Keyword(s):  
Replication Stress ◽  
Bloom Syndrome ◽  
Holliday Junctions ◽  
Replication Forks ◽  
Single Stranded Dna ◽  
Ssdna Binding ◽  
Ssdna Binding Protein ◽  
Dna Replication Stress ◽  
Dna End Resection ◽  
Stalled Replication Forks

AbstractThe Bloom syndrome helicase BLM interacts with topoisomerase IIIα (TOP3A), RMI1 and RMI2 to form the BTR complex, which dissolves double Holliday junctions to produce non-crossover homologous recombination (HR) products. BLM also promotes DNA-end resection, restart of stalled replication forks, and processing of ultra-fine DNA bridges in mitosis. How these activities of the BTR complex are regulated in cells is still unclear. Here, we identify multiple conserved motifs within the BTR complex that interact cooperatively with the single-stranded DNA (ssDNA)-binding protein RPA. Furthermore, we demonstrate that RPA-binding is required for stable BLM recruitment to sites of DNA replication stress and for fork restart, but not for its roles in HR or mitosis. Our findings suggest a model in which the BTR complex contains the intrinsic ability to sense levels of RPA-ssDNA at replication forks, which controls BLM recruitment and activation in response to replication stress.

Human RecQ helicases in transcription-associated stress management: bridging the gap between DNA and RNA metabolism

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Tulika Das ◽  
Surasree Pal ◽  
Agneyo Ganguly
Keyword(s):  
Genome Integrity ◽  
Complex Structures ◽  
Huge Number ◽  
Dna Helicases ◽  
Dna Structures ◽  
Recq Helicases ◽  
Dna And Rna ◽  
Cellular Dna ◽  
Almost All ◽  
Transcription And Replication

Abstract RecQ helicases are a highly conserved class of DNA helicases that play crucial role in almost all DNA metabolic processes including replication, repair and recombination. They are able to unwind a wide variety of complex intermediate DNA structures that may result from cellular DNA transactions and hence assist in maintaining genome integrity. Interestingly, a huge number of recent reports suggest that many of the RecQ family helicases are directly or indirectly involved in regulating transcription and gene expression. On one hand, they can remove complex structures like R-loops, G-quadruplexes or RNA:DNA hybrids formed at the intersection of transcription and replication. On the other hand, emerging evidence suggests that they can also regulate transcription by directly interacting with RNA polymerase or recruiting other protein factors that may regulate transcription. This review summarizes the up to date knowledge on the involvement of three human RecQ family proteins BLM, WRN and RECQL5 in transcription regulation and management of transcription associated stress.

Solution structure of the RecQ C-terminal domain of human Bloom syndrome protein

2014 ◽  
Vol 58 (2) ◽  
pp. 141-147 ◽  
Author(s):  
Chin-Ju Park ◽  
Junsang Ko ◽  
Kyoung-Seok Ryu ◽  
Byong-Seok Choi
Keyword(s):  
Solution Structure ◽  
Bloom Syndrome ◽  
Terminal Domain ◽  
Syndrome Protein

scholarly journals Non-B DNA Secondary Structures and Their Resolution by RecQ Helicases

2011 ◽  
Vol 2011 ◽  
pp. 1-15 ◽  
Author(s):  
Sudha Sharma
Keyword(s):  
Transcriptional Control ◽  
Molecular Targets ◽  
Secondary Structures ◽  
Special Focus ◽  
Dna Helicases ◽  
Dna Structures ◽  
Recq Helicases ◽  
Alternative Structures ◽  
Dna Secondary Structures ◽  
Secondary Dna Structures

In addition to the canonical B-form structure first described by Watson and Crick, DNA can adopt a number of alternative structures. These non-B-form DNA secondary structures form spontaneously on tracts of repeat sequences that are abundant in genomes. In addition, structured forms of DNA with intrastrand pairing may arise on single-stranded DNA produced transiently during various cellular processes. Such secondary structures have a range of biological functions but also induce genetic instability. Increasing evidence suggests that genomic instabilities induced by non-B DNA secondary structures result in predisposition to diseases. Secondary DNA structures also represent a new class of molecular targets for DNA-interactive compounds that might be useful for targeting telomeres and transcriptional control. The equilibrium between the duplex DNA and formation of multistranded non-B-form structures is partly dependent upon the helicases that unwind (resolve) these alternate DNA structures. With special focus on tetraplex, triplex, and cruciform, this paper summarizes the incidence of non-B DNA structures and their association with genomic instability and emphasizes the roles of RecQ-like DNA helicases in genome maintenance by resolution of DNA secondary structures. In future, RecQ helicases are anticipated to be additional molecular targets for cancer chemotherapeutics.

scholarly journals Interaction of replication protein A with two acidic peptides from human Bloom syndrome protein

FEBS Letters ◽  
2018 ◽  
Vol 592 (4) ◽  
pp. 547-558 ◽  
Author(s):  
Donguk Kang ◽  
Sungjin Lee ◽  
Kyoung‐Seok Ryu ◽  
Hae‐Kap Cheong ◽  
Eun‐Hee Kim ◽  
...  
Keyword(s):  
Protein A ◽  
Replication Protein A ◽  
Bloom Syndrome ◽  
Replication Protein ◽  
Syndrome Protein ◽  
Acidic Peptides

scholarly journals Bloom syndrome protein restrains innate immune sensing of micronuclei by cGAS

2019 ◽  
Vol 216 (5) ◽  
pp. 1199-1213 ◽  
Author(s):  
Matthieu Gratia ◽  
Mathieu P. Rodero ◽  
Cécile Conrad ◽  
Elias Bou Samra ◽  
Mathieu Maurin ◽  
...  
Keyword(s):  
Dna Damage ◽  
Immune Responses ◽  
Genome Instability ◽  
Bloom Syndrome ◽  
Innate Immune ◽  
Genome Integrity ◽  
Immune Sensing ◽  
Syndrome Protein ◽  
Innate Immune Sensing ◽  
Exonuclease Trex1

Cellular innate immune sensors of DNA are essential for host defense against invading pathogens. However, the presence of self-DNA inside cells poses a risk of triggering unchecked immune responses. The mechanisms limiting induction of inflammation by self-DNA are poorly understood. BLM RecQ–like helicase is essential for genome integrity and is deficient in Bloom syndrome (BS), a rare genetic disease characterized by genome instability, accumulation of micronuclei, susceptibility to cancer, and immunodeficiency. Here, we show that BLM-deficient fibroblasts show constitutive up-regulation of inflammatory interferon-stimulated gene (ISG) expression, which is mediated by the cGAS–STING–IRF3 cytosolic DNA–sensing pathway. Increased DNA damage or down-regulation of the cytoplasmic exonuclease TREX1 enhances ISG expression in BLM-deficient fibroblasts. cGAS-containing cytoplasmic micronuclei are increased in BS cells. Finally, BS patients demonstrate elevated ISG expression in peripheral blood. These results reveal that BLM limits ISG induction, thus connecting DNA damage to cellular innate immune response, which may contribute to human pathogenesis.

Sign in / Sign up

Export Citation Format

Share Document