scholarly journals Werner syndrome helicase modulates G4 DNA-dependent transcription and opposes mechanistically distinct senescence-associated gene expression programs

2015 ◽  
Author(s):  
Weiliang Tang ◽  
Ana I. Robles ◽  
Richard P. Beyer ◽  
Lucas T. Gray ◽  
Giang Hong Nguyen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Genome Stability ◽  
Werner Syndrome ◽  
Premature Aging ◽  
Dna Motifs ◽  
Trna Synthetases ◽  
Over Expression ◽  
G4 Dna ◽  
G Quadruplex ◽  
Insight Into

Werner syndrome (WS) is a prototypic heritable adult human progeroid syndrome in which signs of premature aging are associated with genetic instability and an elevated risk of specific types of cancer. We have quantified mRNA and microRNA (miRNA) expression in WS patient fibroblasts, and in WRN-depleted fibroblasts. Genes down-regulated in WS patient fibroblasts were highly enriched in G-quadruplex (G4) DNA motifs. The strength, location and strand specificity of this association provide strong experimental evidence that G4 motifs or motif-dependent G-quadruplexes are bound by WRN in human cells to modulate gene expression. The expression of many miRNAs was perturbed by loss of WRN function. WRN depletion altered the expression of >500 miRNAs. miRNAs linked to cell signaling, genome stability assurance and tumorigenesis were among the small number of these miRNAs that were persistently altered in WS patient fibroblasts. An unexpected and highly distinct finding in WS cells was the coordinate over-expression of nearly all cytoplasmic tRNA synthetases and their associated AIMP proteins. Our results provide new insight into WS pathogenesis, and identify therapeutically accessible mechanisms that may drive disease pathogenesis in WS and in the general population.

scholarly journals Human WRN is an intrinsic inhibitor of progerin, abnormal splicing product of lamin A

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
So-mi Kang ◽  
Min-Ho Yoon ◽  
Su-Jin Lee ◽  
Jinsook Ahn ◽  
Sang Ah Yi ◽  
...  
Keyword(s):  
Gene Expression ◽  
Life Span ◽  
Expression Analysis ◽  
Gene Expression Analysis ◽  
Werner Syndrome ◽  
Genetic Disorder ◽  
Dna Helicase ◽  
Premature Aging ◽  
Lamin A ◽  
Short Life Span

AbstractWerner syndrome (WRN) is a rare progressive genetic disorder, caused by functional defects in WRN protein and RecQ4L DNA helicase. Acceleration of the aging process is initiated at puberty and the expected life span is approximately the late 50 s. However, a Wrn-deficient mouse model does not show premature aging phenotypes or a short life span, implying that aging processes differ greatly between humans and mice. Gene expression analysis of WRN cells reveals very similar results to gene expression analysis of Hutchinson Gilford progeria syndrome (HGPS) cells, suggesting that these human progeroid syndromes share a common pathological mechanism. Here we show that WRN cells also express progerin, an abnormal variant of the lamin A protein. In addition, we reveal that duplicated sequences of human WRN (hWRN) from exon 9 to exon 10, which differ from the sequence of mouse WRN (mWRN), are a natural inhibitor of progerin. Overexpression of hWRN reduced progerin expression and aging features in HGPS cells. Furthermore, the elimination of progerin by siRNA or a progerin-inhibitor (SLC-D011 also called progerinin) can ameliorate senescence phenotypes in WRN fibroblasts and cardiomyocytes, derived from WRN-iPSCs. These results suggest that progerin, which easily accumulates under WRN-deficient conditions, can lead to premature aging in WRN and that this effect can be prevented by SLC-D011.

scholarly journals ATRX promotes heterochromatin formation to protect cells from G-quadruplex DNA-mediated stress

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yu-Ching Teng ◽  
Aishwarya Sundaresan ◽  
Ryan O’Hara ◽  
Vincent U. Gant ◽  
Minhua Li ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Genome Stability ◽  
Helicase Domain ◽  
Quadruplex Dna ◽  
Heterochromatin Formation ◽  
Replicative Stress ◽  
G4 Dna ◽  
Mutation Burden ◽  
G Quadruplex ◽  
Dna Replication Stress

AbstractATRX is a tumor suppressor that has been associated with protection from DNA replication stress, purportedly through resolution of difficult-to-replicate G-quadruplex (G4) DNA structures. While several studies demonstrate that loss of ATRX sensitizes cells to chemical stabilizers of G4 structures, the molecular function of ATRX at G4 regions during replication remains unknown. Here, we demonstrate that ATRX associates with a number of the MCM replication complex subunits and that loss of ATRX leads to G4 structure accumulation at newly synthesized DNA. We show that both the helicase domain of ATRX and its H3.3 chaperone function are required to protect cells from G4-induced replicative stress. Furthermore, these activities are upstream of heterochromatin formation mediated by the histone methyltransferase, ESET, which is the critical molecular event that protects cells from G4-mediated stress. In support, tumors carrying mutations in either ATRX or ESET show increased mutation burden at G4-enriched DNA sequences. Overall, our study provides new insights into mechanisms by which ATRX promotes genome stability with important implications for understanding impacts of its loss on human disease.

scholarly journals Helicases FANCJ, RTEL1 and BLM Act on Guanine Quadruplex DNA in Vivo

Genes ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 870 ◽  
Author(s):  
Peter Lansdorp ◽  
Niek van Wietmarschen
Keyword(s):  
Gene Expression ◽  
Genome Stability ◽  
Cell Function ◽  
Historical Context ◽  
Telomere Maintenance ◽  
Dna Structures ◽  
G4 Dna ◽  
Guanine Quadruplex

Guanine quadruplex (G4) structures are among the most stable secondary DNA structures that can form in vitro, and evidence for their existence in vivo has been steadily accumulating. Originally described mainly for their deleterious effects on genome stability, more recent research has focused on (potential) functions of G4 structures in telomere maintenance, gene expression, and other cellular processes. The combined research on G4 structures has revealed that properly regulating G4 DNA structures in cells is important to prevent genome instability and disruption of normal cell function. In this short review we provide some background and historical context of our work resulting in the identification of FANCJ, RTEL1 and BLM as helicases that act on G4 structures in vivo. Taken together these studies highlight important roles of different G4 DNA structures and specific G4 helicases at selected genomic locations and telomeres in regulating gene expression and maintaining genome stability.

scholarly journals The Relevance of G-Quadruplexes for DNA Repair

2021 ◽  
Vol 22 (22) ◽  
pp. 12599
Author(s):  
Rebecca Linke ◽  
Michaela Limmer ◽  
Stefan Juranek ◽  
Annkristin Heine ◽  
Katrin Paeschke
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Genome Stability ◽  
Genome Instability ◽  
Genetic Disorders ◽  
Telomere Maintenance ◽  
Dna Structures ◽  
G4 Dna ◽  
G Quadruplex ◽  
Repair Pathways

DNA molecules can adopt a variety of alternative structures. Among these structures are G-quadruplex DNA structures (G4s), which support cellular function by affecting transcription, translation, and telomere maintenance. These structures can also induce genome instability by stalling replication, increasing DNA damage, and recombination events. G-quadruplex-driven genome instability is connected to tumorigenesis and other genetic disorders. In recent years, the connection between genome stability, DNA repair and G4 formation was further underlined by the identification of multiple DNA repair proteins and ligands which bind and stabilize said G4 structures to block specific DNA repair pathways. The relevance of G4s for different DNA repair pathways is complex and depends on the repair pathway itself. G4 structures can induce DNA damage and block efficient DNA repair, but they can also support the activity and function of certain repair pathways. In this review, we highlight the roles and consequences of G4 DNA structures for DNA repair initiation, processing, and the efficiency of various DNA repair pathways.

scholarly journals Werner Syndrome Protein and DNA Replication

2018 ◽  
Vol 19 (11) ◽  
pp. 3442 ◽  
Author(s):  
Shibani Mukherjee ◽  
Debapriya Sinha ◽  
Souparno Bhattacharya ◽  
Kalayarasan Srinivasan ◽  
Salim Abdisalaam ◽  
...  
Keyword(s):  
Dna Replication ◽  
Ataxia Telangiectasia ◽  
Replication Fork ◽  
Genome Stability ◽  
Werner Syndrome ◽  
Genotoxic Stress ◽  
Premature Aging ◽  
Replication Forks ◽  
Werner Syndrome Protein ◽  
Syndrome Protein

Werner Syndrome (WS) is an autosomal recessive disorder characterized by the premature development of aging features. Individuals with WS also have a greater predisposition to rare cancers that are mesenchymal in origin. Werner Syndrome Protein (WRN), the protein mutated in WS, is unique among RecQ family proteins in that it possesses exonuclease and 3′ to 5′ helicase activities. WRN forms dynamic sub-complexes with different factors involved in DNA replication, recombination and repair. WRN binding partners either facilitate its DNA metabolic activities or utilize it to execute their specific functions. Furthermore, WRN is phosphorylated by multiple kinases, including Ataxia telangiectasia mutated, Ataxia telangiectasia and Rad3 related, c-Abl, Cyclin-dependent kinase 1 and DNA-dependent protein kinase catalytic subunit, in response to genotoxic stress. These post-translational modifications are critical for WRN to function properly in DNA repair, replication and recombination. Accumulating evidence suggests that WRN plays a crucial role in one or more genome stability maintenance pathways, through which it suppresses cancer and premature aging. Among its many functions, WRN helps in replication fork progression, facilitates the repair of stalled replication forks and DNA double-strand breaks associated with replication forks, and blocks nuclease-mediated excessive processing of replication forks. In this review, we specifically focus on human WRN’s contribution to replication fork processing for maintaining genome stability and suppressing premature aging. Understanding WRN’s molecular role in timely and faithful DNA replication will further advance our understanding of the pathophysiology of WS.

scholarly journals Self-assembled Pt2L2 boxes strongly bind G-quadruplex DNA and influence gene expression in cancer cells

2017 ◽  
Vol 46 (2) ◽  
pp. 329-332 ◽  
Author(s):  
O. Domarco ◽  
D. Lötsch ◽  
J. Schreiber ◽  
C. Dinhof ◽  
S. Van Schoonhoven ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cancer Cells ◽  
Quadruplex Dna ◽  
Dna Motifs ◽  
Size Dependent ◽  
G Quadruplex ◽  
Self Assembled ◽  
Influence Gene Expression

Pt(ii) boxes bind native and G-quadruplex DNA motifs in a size-dependent fashion and influence the expression of G-quadruplex forming genes.

scholarly journals The i-Motif as a Molecular Target: More Than a Complementary DNA Secondary Structure

2021 ◽  
Vol 14 (2) ◽  
pp. 96
Author(s):  
Susie L. Brown ◽  
Samantha Kendrick
Keyword(s):  
Gene Expression ◽  
Secondary Structure ◽  
Biological Function ◽  
Molecular Target ◽  
Therapeutic Approaches ◽  
Promoter Regions ◽  
New Therapeutic Approaches ◽  
G Quadruplex ◽  
Dna Elements ◽  
Insight Into

Stretches of cytosine-rich DNA are capable of adopting a dynamic secondary structure, the i-motif. When within promoter regions, the i-motif has the potential to act as a molecular switch for controlling gene expression. However, i-motif structures in genomic areas of repetitive nucleotide sequences may play a role in facilitating or hindering expansion of these DNA elements. Despite research on the i-motif trailing behind the complementary G-quadruplex structure, recent discoveries including the identification of a specific i-motif antibody are pushing this field forward. This perspective reviews initial and current work characterizing the i-motif and providing insight into the biological function of this DNA structure, with a focus on how the i-motif can serve as a molecular target for developing new therapeutic approaches to modulate gene expression and extension of repetitive DNA.

Human Pif1 helicase is a G-quadruplex DNA-binding protein with G-quadruplex DNA-unwinding activity

2010 ◽  
Vol 430 (1) ◽  
pp. 119-128 ◽  
Author(s):  
Cyril M. Sanders
Keyword(s):  
Dna Binding ◽  
Dna Sequences ◽  
Genome Stability ◽  
Dna Helicase ◽  
Dna Unwinding ◽  
Helicase Domain ◽  
Quadruplex Dna ◽  
G4 Dna ◽  
G Quadruplex ◽  
Pif1 Helicase

Pif1 proteins are helicases that in yeast are implicated in the maintenance of genome stability. One activity of Saccharomyces cerevisiae Pif1 is to stabilize DNA sequences that could otherwise form deleterious G4 (G-quadruplex) structures by acting as a G4 resolvase. The present study shows that human Pif1 (hPif1, nuclear form) is a G4 DNA-binding and resolvase protein and that these activities are properties of the conserved helicase domain (amino acids 206–620 of 641, hPifHD). hPif1 preferentially bound synthetic G4 DNA relative to ssDNA (single-stranded DNA), dsDNA (double-stranded DNA) and a partially single-stranded duplex DNA helicase substrate. G4 DNA unwinding, but not binding, required an extended (>10 nucleotide) 5′ ssDNA tail, and in competition assays, G4 DNA was an ineffective suppressor of helicase activity compared with ssDNA. These results suggest a distinction between the determinants of G4 DNA binding and the ssDNA interactions required for helicase action and that hPif1 may act on G4 substrates by binding alone or as a resolvase. Human Pif1 could therefore have a role in processing G4 structures that arise in the single-stranded nucleic acid intermediates formed during DNA replication and gene expression.

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

2017 ◽  
Vol 292 (8) ◽  
pp. 3154-3163 ◽  
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.

scholarly journals Regulation of gene expression by the BLM helicase correlates with the presence of G-quadruplex DNA motifs

2014 ◽  
Vol 111 (27) ◽  
pp. 9905-9910 ◽  
Author(s):  
Giang Huong Nguyen ◽  
Weiliang Tang ◽  
Ana I. Robles ◽  
Richard P. Beyer ◽  
Lucas T. Gray ◽  
...  
Keyword(s):  
Gene Expression ◽  
Regulation Of Gene Expression ◽  
Quadruplex Dna ◽  
Dna Motifs ◽  
Blm Helicase ◽  
G Quadruplex
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