scholarly journals A SWI/SNF subunit regulates chromosomal dissociation of structural maintenance complex 5 during DNA repair in plant cells

2019 ◽  
Vol 116 (30) ◽  
pp. 15288-15296 ◽  
Author(s):  
Jieming Jiang ◽  
Ning Mao ◽  
Huan Hu ◽  
Jiahang Tang ◽  
Danlu Han ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Genome Stability ◽  
Damage Accumulation ◽  
Protein Complexes ◽  
Plant Cells ◽  
Strand Break ◽  
Interacting Protein ◽  
Dna Double Strand Break ◽  
A Subunit

DNA damage decreases genome stability and alters genetic information in all organisms. Conserved protein complexes have been evolved for DNA repair in eukaryotes, such as the structural maintenance complex 5/6 (SMC5/6), a chromosomal ATPase involved in DNA double-strand break (DSB) repair. Several factors have been identified for recruitment of SMC5/6 to DSBs, but this complex is also associated with chromosomes under normal conditions; how SMC5/6 dissociates from its original location and moves to DSB sites is completely unknown. In this study, we determined that SWI3B, a subunit of the SWI/SNF complex, is an SMC5-interacting protein in Arabidopsis thialiana. Knockdown of SWI3B or SMC5 results in increased DNA damage accumulation. During DNA damage, SWI3B expression is induced, but the SWI3B protein is not localized at DSBs. Notably, either knockdown or overexpression of SWI3B disrupts the DSB recruitment of SMC5 in response to DNA damage. Overexpression of a cotranscriptional activator ADA2b rescues the DSB localization of SMC5 dramatically in the SWI3B-overexpressing cells but only weakly in the SWI3B knockdown cells. Biochemical data confirmed that ADA2b attenuates the interaction between SWI3B and SMC5 and that SWI3B promotes the dissociation of SMC5 from chromosomes. In addition, overexpression of SMC5 reduces DNA damage accumulation in the SWI3B knockdown plants. Collectively, these results indicate that the presence of an appropriate level of SWI3B enhances dissociation of SMC5 from chromosomes for its further recruitment at DSBs during DNA damage in plant cells.

scholarly journals Akt/PKB suppresses DNA damage processing and checkpoint activation in late G2

2010 ◽  
Vol 190 (3) ◽  
pp. 297-305 ◽  
Author(s):  
Naihan Xu ◽  
Nadia Hegarat ◽  
Elizabeth J. Black ◽  
Mary T. Scott ◽  
Helfrid Hochegger ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Protein A ◽  
Strand Break ◽  
Checkpoint Activation ◽  
Interacting Protein ◽  
Dna Double Strand Break ◽  
Radiation Induced ◽  
G2 Cells ◽  
Tumor Types

Using chemical genetics to reversibly inhibit Cdk1, we find that cells arrested in late G2 are unable to delay mitotic entry after irradiation. Late G2 cells detect DNA damage lesions and form γ-H2AX foci but fail to activate Chk1. This reflects a lack of DNA double-strand break processing because late G2 cells fail to recruit RPA (replication protein A), ATR (ataxia telangiectasia and Rad3 related), Rad51, or CtIP (C-terminal interacting protein) to sites of radiation-induced damage, events essential for both checkpoint activation and initiation of DNA repair by homologous recombination. Remarkably, inhibition of Akt/PKB (protein kinase B) restores DNA damage processing and Chk1 activation after irradiation in late G2. These data demonstrate a previously unrecognized role for Akt in cell cycle regulation of DNA repair and checkpoint activation. Because Akt/PKB is frequently activated in many tumor types, these findings have important implications for the evolution and therapy of such cancers.

Perfecting DNA double-strand break repair on transcribed chromatin

2020 ◽  
Vol 64 (5) ◽  
pp. 705-719 ◽  
Author(s):  
Xin Yi Tan ◽  
Michael S.Y. Huen
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Chromosomal Aberrations ◽  
Chromatin Structure ◽  
Genome Stability ◽  
Transcriptional Control ◽  
Strand Break ◽  
Double Strand Break ◽  
Dna Double Strand Break ◽  
Molecular Bases

Abstract Timely repair of DNA double-strand break (DSB) entails coordination with the local higher order chromatin structure and its transaction activities, including transcription. Recent studies are uncovering how DSBs trigger transient suppression of nearby transcription to permit faithful DNA repair, failing of which leads to elevated chromosomal aberrations and cell hypersensitivity to DNA damage. Here, we summarize the molecular bases for transcriptional control during DSB metabolism, and discuss how the exquisite coordination between the two DNA-templated processes may underlie maintenance of genome stability and cell homeostasis.

scholarly journals Emerging roles of RNA modifications in genome integrity

2020 ◽  
Author(s):  
Seo Yun Lee ◽  
Jae Jin Kim ◽  
Kyle M Miller
Keyword(s):  
Gene Expression ◽  
Dna Damage ◽  
Dna Repair ◽  
Genome Stability ◽  
Strand Break ◽  
Human Diseases ◽  
Genome Integrity ◽  
Rna Modification ◽  
Rna Modifications ◽  
Dna Double Strand Break

Abstract Post-translational modifications of proteins are well-established participants in DNA damage response (DDR) pathways, which function in the maintenance of genome integrity. Emerging evidence is starting to reveal the involvement of modifications on RNA in the DDR. RNA modifications are known regulators of gene expression but how and if they participate in DNA repair and genome maintenance has been poorly understood. Here, we review several studies that have now established RNA modifications as key components of DNA damage responses. RNA modifying enzymes and the binding proteins that recognize these modifications localize to and participate in the repair of UV-induced and DNA double-strand break lesions. RNA modifications have a profound effect on DNA–RNA hybrids (R-loops) at DNA damage sites, a structure known to be involved in DNA repair and genome stability. Given the importance of the DDR in suppressing mutations and human diseases such as neurodegeneration, immunodeficiencies, cancer and aging, RNA modification pathways may be involved in human diseases not solely through their roles in gene expression but also by their ability to impact DNA repair and genome stability.

scholarly journals Human SIRT6 Promotes DNA End Resection Through CtIP Deacetylation

Science ◽  
2010 ◽  
Vol 329 (5997) ◽  
pp. 1348-1353 ◽  
Author(s):  
Abderrahmane Kaidi ◽  
Brian T. Weinert ◽  
Chunaram Choudhary ◽  
Stephen P. Jackson
Keyword(s):  
Homologous Recombination ◽  
Genome Stability ◽  
Protein A ◽  
Strand Break ◽  
Dsb Repair ◽  
Interacting Protein ◽  
Dna Double Strand Break ◽  
Dna End Resection ◽  
Lysine Deacetylases ◽  
End Resection

SIRT6 belongs to the sirtuin family of protein lysine deacetylases, which regulate aging and genome stability. We found that human SIRT6 has a role in promoting DNA end resection, a crucial step in DNA double-strand break (DSB) repair by homologous recombination. SIRT6 depletion impaired the accumulation of replication protein A and single-stranded DNA at DNA damage sites, reduced rates of homologous recombination, and sensitized cells to DSB-inducing agents. We identified the DSB resection protein CtIP [C-terminal binding protein (CtBP) interacting protein] as a SIRT6 interaction partner and showed that SIRT6-dependent CtIP deacetylation promotes resection. A nonacetylatable CtIP mutant alleviated the effect of SIRT6 depletion on resection, thus identifying CtIP as a key substrate by which SIRT6 facilitates DSB processing and homologous recombination. These findings further clarify how SIRT6 promotes genome stability.

Control of genome stability by Slx protein complexes

2009 ◽  
Vol 37 (3) ◽  
pp. 495-510 ◽  
Author(s):  
John Rouse
Keyword(s):  
Dna Damage ◽  
Dna Replication ◽  
Protein Interactions ◽  
Cellular Response ◽  
Genome Stability ◽  
Molecular Mechanisms ◽  
Excision Repair ◽  
Protein Complexes ◽  
Alkylating Agents ◽  
Strand Break

The six Saccharomyces cerevisiae SLX genes were identified in a screen for factors required for the viability of cells lacking Sgs1, a member of the RecQ helicase family involved in processing stalled replisomes and in the maintenance of genome stability. The six SLX gene products form three distinct heterodimeric complexes, and all three have catalytic activity. Slx3–Slx2 (also known as Mus81–Mms4) and Slx1–Slx4 are both heterodimeric endonucleases with a marked specificity for branched replication fork-like DNA species, whereas Slx5–Slx8 is a SUMO (small ubiquitin-related modifier)-targeted E3 ubiquitin ligase. All three complexes play important, but distinct, roles in different aspects of the cellular response to DNA damage and perturbed DNA replication. Slx4 interacts physically not only with Slx1, but also with Rad1–Rad10 [XPF (xeroderma pigmentosum complementation group F)–ERCC1 (excision repair cross-complementing 1) in humans], another structure-specific endonuclease that participates in the repair of UV-induced DNA damage and in a subpathway of recombinational DNA DSB (double-strand break) repair. Curiously, Slx4 is essential for repair of DSBs by Rad1–Rad10, but is not required for repair of UV damage. Slx4 also promotes cellular resistance to DNA-alkylating agents that block the progression of replisomes during DNA replication, by facilitating the error-free mode of lesion bypass. This does not require Slx1 or Rad1–Rad10, and so Slx4 has several distinct roles in protecting genome stability. In the present article, I provide an overview of our current understanding of the cellular roles of the Slx proteins, paying particular attention to the advances that have been made in understanding the cellular roles of Slx4. In particular, protein–protein interactions and underlying molecular mechanisms are discussed and I draw attention to the many questions that have yet to be answered.

The complex matter of DNA double-strand break detection

2003 ◽  
Vol 31 (1) ◽  
pp. 40-44 ◽  
Author(s):  
J.M. Bradbury ◽  
S.P. Jackson
Keyword(s):  
Dna Damage ◽  
Genome Stability ◽  
Strand Break ◽  
Damage Sensing ◽  
Dna Double Strand Break ◽  
Mre11 Complex ◽  
Damage Response ◽  
Radiation Induced ◽  
Dna Damage Signalling ◽  
Complex Matter

To maintain genomic stability, despite constant exposure to agents that damage DNA, eukaryotic cells have developed elaborate and highly conserved pathways of DNA damage sensing, signalling and repair. In this review, we concentrate mainly on what we know about DNA damage sensing with particular reference to Lcd1p, a yeast protein that functions early in DNA damage signalling, and MDC1 (mediator of DNA damage checkpoint 1), a recently identified human protein that may be involved in recruiting the MRE11 complex to radiation-induced nuclear foci. We describe a model for the DNA damage response in which factors are recruited sequentially to sites of DNA damage to form complexes that can amplify the original signal and propagate it to the multitude of response pathways necessary for genome stability.

scholarly journals HP1β Chromo Shadow Domain facilitates H2A ubiquitination for BRCA1 recruitment at DNA double-strand breaks

2022 ◽  
Author(s):  
Tej Pandita ◽  
Vijay Kumari Charaka ◽  
Sharmistha Chakraborty ◽  
Chi-Lin Tsai ◽  
Xiaoyan Wang ◽  
...  
Keyword(s):  
Dna Damage ◽  
Genome Stability ◽  
Strand Break ◽  
Dna Double Strand Breaks ◽  
Dsb Repair ◽  
Strand Breaks ◽  
Damage Repair ◽  
Dna Double Strand Break ◽  
Assembly Factor ◽  
Chromo Shadow Domain

Efficient DNA double strand break (DSB) repair by homologous recombination (HR), as orchestrated by histone and non-histone proteins, is critical to genome stability, replication, transcription, and cancer avoidance. Here we report that Heterochromatin Protein1 beta (HP1β) acts as a key component of the HR DNA resection step by regulating BRCA1 enrichment at DNA damage sites, a function largely dependent on the HP1β chromo shadow domain (CSD). HP1β itself is enriched at DSBs within gene-rich regions through a CSD interaction with Chromatin Assembly Factor 1 (CAF1) and HP1β depletion impairs subsequent BRCA1 enrichment. An added interaction of the HP1β CSD with the Polycomb Repressor Complex 1 ubiquitinase component RING1A facilitates BRCA1 recruitment by increasing H2A lysine 118-119 ubiquitination, a marker for BRCA1 recruitment. Our findings reveal that HP1β interactions, mediated through its CSD with RING1A, promote H2A ubiquitination and facilitate BRCA1 recruitment at DNA damage sites, a critical step in DSB repair by the HR pathway. These collective results unveil how HP1β is recruited to DSBs in gene-rich regions and how HP1β subsequently promotes BRCA1 recruitment to further HR DNA damage repair by stimulating CtIP-dependent resection.

scholarly journals RIF1 acts in DNA repair through phosphopeptide recognition of 53BP1

2021 ◽  
Author(s):  
Dheva Setiaputra ◽  
Cristina Escribano-Diaz ◽  
Julia K. Reinert ◽  
Pooja Sadana ◽  
Dali Zong ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Binding Sites ◽  
Binding Protein ◽  
Strand Break ◽  
Chromatin Binding ◽  
Alternative Mode ◽  
Downstream Effectors ◽  
Dna Double Strand Break ◽  
Radiation Induced

SummaryThe chromatin-binding protein 53BP1 promotes DNA repair by orchestrating the recruitment of downstream effectors including PTIP, RIF1 and shieldin to DNA double-strand break sites. While how PTIP recognizes 53BP1 is known, the molecular details of RIF1 recruitment to DNA damage sites remains undefined. Here, we report that RIF1 is a phosphopeptide-binding protein that directly interacts with three phosphorylated 53BP1 epitopes. The RIF1-binding sites on 53BP1 share an essential LxL motif followed by two closely apposed phosphorylated residues. Simultaneous mutation of these sites on 53BP1 abrogates RIF1 accumulation into ionizing radiation-induced foci, but surprisingly only fully compromises 53BP1-dependent DNA repair when an alternative mode of shieldin recruitment to DNA damage sites is also disabled. Intriguingly, this alternative mode of recruitment still depends on RIF1 but does not require its interaction with 53BP1. RIF1 therefore employs phosphopeptide recognition to promote DNA repair but also modifies shieldin action independently of 53BP1 binding.

scholarly journals Genomic Instability and the Oncohistone H3K27M Drive Gliomagenesis in a Murine Model

2020 ◽  
Author(s):  
◽  
Lee Pribyl ◽  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Progenitor Cells ◽  
Neural Development ◽  
Genome Stability ◽  
Damage Accumulation ◽  
Genome Instability ◽  
Cortical Development ◽  
Neural Cells ◽  
Repair Pathways

Maintaining genome stability is crucial for human health and it is of particular importance in neural cells during early brain development. Genome maintenance occurs at two broad stages; surveillance during DNA replication and DNA damage repair in differentiating and mature cells. Neural cells are particularly sensitive to DNA strand breaks and defective DNA damage responses can result in detrimental effects on the nervous system, including cancer. Multiple DNA repair pathways play critical roles in preventing DNA damage accumulation in stem and neural progenitor cells. The mechanisms that protect progenitor genomes also suppress DNA mutations that can result in cancer. A primary objective of this dissertation is to understand the relative contributions of key DNA repair factors that prevent tumorigenesis during cortical development. We have compared the differential effects of inhibition of homologous recombination (HR), via BRCA2-inactivation and non-homologous end-joining (NHEJ), via LIG4-inactivation towards tumorigenesis by directing their deletion specifically to early cortical progenitors using an Emx1-cre recombinase driver. We find that coincident loss of either of these repair pathways with p53 inhibition result in distinct high-grade glioma (HGG) formation resulting from elevated genome instability by DNA damage accumulation during embryogenesis. Furthermore, the presence of the oncohistone H3K27M mutation, commonly found in pediatric HGGs, enhances genome instability and accelerates cortical gliomagenesis with p53 inactivation and defective HR or NHEJ. Additionally, the H3K27M resultant gliomas showed distinctive differences in increased brain tumor penetrance and diffusion. Through RNA-sequencing and whole exome sequencing we identify upregulation of genes normally controlled by bivalent gene promoter post-translational modifications, which result in transcriptional alterations in genes important for both neural development and tumorigenesis. Mechanistically, this is done by targeting specific populations of cortical cells that are more susceptible to DNA damage and transformations that may cause additional critical mutations during a limited timeframe of early cortical development which eventually result in HGGs. We provide evidence supporting that BRCA2 functions to provide DSBR and genome stability to the early-born proliferating cortical progenitor cell population, while LIG4 provides the same function but to a lesser extent to progenitor cells and more so to post-mitotic neurons. Since, epigenetic regulation is tightly connected with neural development and differentiation, we propose the specific genes that H3K27M effects may differ depending on the time period and particular cell state from which the HGG initiates. We believe this contributes to reduced heterogeneity in glioma expression signatures with H3K27M in addition to either HR- or NHEJ-deficiency. Ultimately this work highlights the power of inducible genetically engineered mouse models as an approach to better understand the complexities of providing a connection between genome instability and gliomagenesis.

scholarly journals Guardians of the Genome: BRCA2 and Its Partners

Genes ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1229
Author(s):  
Hang Phuong Le ◽  
Wolf-Dietrich Heyer ◽  
Jie Liu
Keyword(s):  
Dna Repair ◽  
Replication Fork ◽  
Genome Stability ◽  
Strand Break ◽  
Fundamental Properties ◽  
Binding Partners ◽  
Dna Double Strand Break ◽  
Interaction Partners ◽  
Brca2 Mutations ◽  
Mechanistic Understanding

The tumor suppressor BRCA2 functions as a central caretaker of genome stability, and individuals who carry BRCA2 mutations are predisposed to breast, ovarian, and other cancers. Recent research advanced our mechanistic understanding of BRCA2 and its various interaction partners in DNA repair, DNA replication support, and DNA double-strand break repair pathway choice. In this review, we discuss the biochemical and structural properties of BRCA2 and examine how these fundamental properties contribute to DNA repair and replication fork stabilization in living cells. We highlight selected BRCA2 binding partners and discuss their role in BRCA2-mediated homologous recombination and fork protection. Improved mechanistic understanding of how BRCA2 functions in genome stability maintenance can enable experimental evidence-based evaluation of pathogenic BRCA2 mutations and BRCA2 pseudo-revertants to support targeted therapy.

Sign in / Sign up

Export Citation Format

Share Document