scholarly journals A critical role for Dna2 at unwound telomeres

2018 ◽  
Author(s):  
Marta Markiewicz-Potoczny ◽  
Michael Lisby ◽  
David Lydall
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Binding Protein ◽  
Critical Role ◽  
Temperature Sensitive ◽  
Critical Function ◽  
Ssdna Binding ◽  
Damage Response ◽  
Ssdna Binding Protein ◽  
A Subunit

AbstractDna2 is a nuclease and helicase that functions redundantly with other proteins in Okazaki fragment processing, double strand break (DSB) resection and checkpoint kinase activation. Dna2 is an essential enzyme, required for yeast and mammalian cell viability. Here we report that numerous mutations affecting the DNA damage checkpoint suppress dna2Δ lethality in Saccharomyces cerevisiae. dna2Δ cells are also suppressed by deletion of helicases, PIF1 and MPH1, and by deletion of POL32, a subunit of DNA polymerase δ. All dna2Δ cells are temperature sensitive, have telomere length defects, and low levels of telomeric 3’ single stranded DNA (ssDNA). Interestingly, Rfa1, a subunit of the major ssDNA binding protein RPA, and the telomere specific ssDNA binding protein Cdc13, often co-localize in dna2Δ cells. This suggests that telomeric defects often occur in dna2Δ cells. There are several plausible explanations for why the most critical function of Dna2 is at telomeres. Telomeres modulate the DNA damage response (DDR) at chromosome ends, inhibiting resection, ligation and cell cycle arrest. We suggest that Dna2 nuclease activity contributes to modulating the DNA damage response at telomeres by removing telomeric C-rich ssDNA and thus preventing checkpoint activation.

Pseudorabies virus infection triggers NF-κB activation via the DNA damage response, but actively inhibits NFkB-dependent gene expression

2021 ◽  
Author(s):  
Nicolás Romero ◽  
Herman W. Favoreel
Keyword(s):  
Gene Expression ◽  
Dna Damage ◽  
Dna Damage Response ◽  
Pseudorabies Virus ◽  
Critical Role ◽  
Genome Replication ◽  
Viral Protein Synthesis ◽  
Damage Response ◽  
Signaling Axis ◽  
Inside Out

The nuclear factor kappa B (NF-κB) pathway is known to integrate signaling associated with very diverse intra- and extracellular stressors including virus infections, and triggers a powerful (pro-inflammatory) response through the expression of NF-κB-regulated genes. Typically, the NF-κB pathway collects and transduces threatening signals at the cell surface or in the cytoplasm leading to nuclear import of activated NF-κB transcription factors. In the current work, we demonstrate that the swine alphaherpesvirus pseudorabies virus (PRV) induces a peculiar mode of NF-κB activation known as “inside-out” NF-κB activation. We show that PRV triggers the DNA damage response (DDR) and that this DDR response drives NF-κB activation since inhibition of the nuclear ataxia telangiectasia-mutated (ATM) kinase, a chief controller of DDR, abolished PRV-induced NF-κB activation. Initiation of the DDR-NF-κB signaling axis requires viral protein synthesis but occurs before active viral genome replication. In addition, the initiation of the DDR-NF-κB signaling axis is followed by a virus-induced complete shutoff of NF-κB-dependent gene expression that depends on viral DNA replication. In summary, the results presented in this study reveal that PRV infection triggers a non-canonical DDR-NF-κB activation signaling axis and that the virus actively inhibits the (potentially antiviral) consequences of this pathway, by inhibiting NF-κB-dependent gene expression. IMPORTANCE: The NF-κB signaling pathway plays a critical role in coordination of innate immune responses that are of vital importance in the control of infections. The current report generates new insights in the interaction of the alphaherpesvirus pseudorabies virus (PRV) with the NF-κB pathway, as they reveal that (i) PRV infection leads to NF-κB activation via a peculiar “inside-out’ nucleus-to-cytoplasm signal that is triggered via the DNA damage response (DDR), (ii) the DDR-NF-κB signaling axis requires expression of viral proteins but is initiated before active PRV replication, and (iii) late viral factor(s) allow PRV to actively and efficiently inhibit NF-κB-dependent (pro-inflammatory) gene expression. These data suggest that activation of the DDR-NF-κB during PRV infection is host-driven and that its potential antiviral consequences are actively inhibited by the virus.

scholarly journals INTS3 controls the hSSB1-mediated DNA damage response

2009 ◽  
Vol 187 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Jeffrey R. Skaar ◽  
Derek J. Richard ◽  
Anita Saraf ◽  
Alfredo Toschi ◽  
Emma Bolderson ◽  
...  
Keyword(s):  
Dna Damage ◽  
Signaling Pathway ◽  
Dna Damage Response ◽  
Ataxia Telangiectasia ◽  
Binding Protein ◽  
Ataxia Telangiectasia Mutated ◽  
Uncharacterized Protein ◽  
Damage Response ◽  
Atm Signaling Pathway ◽  
Atm Signaling

Human SSB1 (single-stranded binding protein 1 [hSSB1]) was recently identified as a part of the ataxia telangiectasia mutated (ATM) signaling pathway. To investigate hSSB1 function, we performed tandem affinity purifications of hSSB1 mutants mimicking the unphosphorylated and ATM-phosphorylated states. Both hSSB1 mutants copurified a subset of Integrator complex subunits and the uncharacterized protein LOC58493/c9orf80 (henceforth minute INTS3/hSSB-associated element [MISE]). The INTS3–MISE–hSSB1 complex plays a key role in ATM activation and RAD51 recruitment to DNA damage foci during the response to genotoxic stresses. These effects on the DNA damage response are caused by the control of hSSB1 transcription via INTS3, demonstrating a new network controlling hSSB1 function.

scholarly journals Down-regulation of Wild-type p53-induced Phosphatase 1 (Wip1) Plays a Critical Role in Regulating Several p53-dependent Functions in Premature Senescent Tumor Cells

2013 ◽  
Vol 288 (23) ◽  
pp. 16212-16224 ◽  
Author(s):  
Elvira Crescenzi ◽  
Zelinda Raia ◽  
Francesco Pacifico ◽  
Stefano Mellone ◽  
Fortunato Moscato ◽  
...  
Keyword(s):  
Dna Damage ◽  
Tumor Cells ◽  
Dna Damage Response ◽  
Critical Role ◽  
Wild Type ◽  
Down Regulation ◽  
Senescent Phenotype ◽  
Response To Chemotherapy ◽  
Damage Response ◽  
Wild Type P53

Premature or drug-induced senescence is a major cellular response to chemotherapy in solid tumors. The senescent phenotype develops slowly and is associated with chronic DNA damage response. We found that expression of wild-type p53-induced phosphatase 1 (Wip1) is markedly down-regulated during persistent DNA damage and after drug release during the acquisition of the senescent phenotype in carcinoma cells. We demonstrate that down-regulation of Wip1 is required for maintenance of permanent G2 arrest. In fact, we show that forced expression of Wip1 in premature senescent tumor cells induces inappropriate re-initiation of mitosis, uncontrolled polyploid progression, and cell death by mitotic failure. Most of the effects of Wip1 may be attributed to its ability to dephosphorylate p53 at Ser15 and to inhibit DNA damage response. However, we also uncover a regulatory pathway whereby suppression of p53 Ser15 phosphorylation is associated with enhanced phosphorylation at Ser46, increased p53 protein levels, and induction of Noxa expression. On the whole, our data indicate that down-regulation of Wip1 expression during premature senescence plays a pivotal role in regulating several p53-dependent aspects of the senescent phenotype.

scholarly journals ATM regulates a DNA damage response posttranscriptional RNA operon in lymphocytes

Blood ◽  
2011 ◽  
Vol 117 (8) ◽  
pp. 2441-2450 ◽  
Author(s):  
Krystyna Mazan-Mamczarz ◽  
Patrick R. Hagner ◽  
Yongqing Zhang ◽  
Bojie Dai ◽  
Elin Lehrmann ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Damage ◽  
Dna Damage Response ◽  
Ataxia Telangiectasia ◽  
Rna Binding ◽  
Critical Role ◽  
Cell Cycle Checkpoints ◽  
Dependent Manner ◽  
Damage Response ◽  
Multiple Cell

Abstract Maintenance of genomic stability depends on the DNA damage response, a biologic barrier in early stages of cancer development. Failure of this response results in genomic instability and high predisposition toward lymphoma, as seen in patients with ataxia-telangiectasia mutated (ATM) dysfunction. ATM activates multiple cell-cycle checkpoints and DNA repair after DNA damage, but its influence on posttranscriptional gene expression has not been examined on a global level. We show that ionizing radiation modulates the dynamic association of the RNA-binding protein HuR with target mRNAs in an ATM-dependent manner, potentially coordinating the genotoxic response as an RNA operon. Pharmacologic ATM inhibition and use of ATM-null cells revealed a critical role for ATM in this process. Numerous mRNAs encoding cancer-related proteins were differentially associated with HuR depending on the functional state of ATM, in turn affecting expression of encoded proteins. The findings presented here reveal a previously unidentified role of ATM in controlling gene expression posttranscriptionally. Dysregulation of this DNA damage response RNA operon is probably relevant to lymphoma development in ataxia-telangiectasia persons. These novel RNA regulatory modules and genetic networks provide critical insight into the function of ATM in oncogenesis.

scholarly journals Suppressor mutations in Mecp2-null mice reveal that the DNA damage response is key to Rett syndrome pathology

2019 ◽  
Author(s):  
Adebola Enikanolaiye ◽  
Julie Ruston ◽  
Rong Zeng ◽  
Christine Taylor ◽  
Marijke Shrock ◽  
...  
Keyword(s):  
Dna Damage ◽  
Candidate Genes ◽  
Rett Syndrome ◽  
Association Analysis ◽  
Dna Damage Response ◽  
Binding Protein ◽  
Symptom Improvement ◽  
Suppressor Mutations ◽  
Entry Points ◽  
Damage Response

AbstractMutations in X-linked methyl-CpG-binding protein 2 (MECP2) cause Rett syndrome (RTT). We carried out a genetic screen for secondary mutations that improved phenotypes in Mecp2/Y mice after mutagenesis with N-ethyl-N-nitrosourea (ENU), aiming to identify potential therapeutic entry points. Here we report the isolation of 106 founder animals that show suppression of Mecp2-null traits from screening 3,177 Mecp2/Y genomes. Using exome sequencing, genetic crosses and association analysis, we identify 33 candidate genes in 30 of the suppressor lines. A network analysis shows that 61% of the candidate genes cluster into the functional categories of transcriptional repression, chromatin modification or DNA repair, delineating a pathway relationship with MECP2. Many mutations lie in genes that are predicted to modulate synaptic signaling or lipid homeostasis. Surprisingly, mutations in genes that function in the DNA damage response (DDR) also improve symptoms in Mecp2/Y mice. The combinatorial effects of multiple loci can be resolved by employing association analysis. One line, which was previously reported to carry a suppressor mutation in a gene required for cholesterol synthesis, Sqle, carries a second mutation in retinoblastoma binding protein 8 (Rbbp8 or CtIP), which regulates a DDR choice in double stranded break (DSB) repair. Cells from Mecp2/Y mice have increased DSBs, so this finding suggests that the balance between homology directed repair and non-homologous end joining is important for neuronal cells. In this and other lines, the presence of two suppressor mutations confers better symptom improvement than one locus alone, suggesting that combination therapies could be effective in RTT.

scholarly journals Immunofluorescence analysis of DNA damage response protein p53-binding protein 1 in a case of uterine dedifferentiated leiomyosarcoma arising from leiomyoma

2019 ◽  
Vol 215 (11) ◽  
pp. 152640
Author(s):  
Katsuya Matsuda ◽  
Yuko Akazawa ◽  
Yuka Yamaguchi ◽  
Zhanna Mussazhanova ◽  
Hirokazu Kurohama ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Binding Protein ◽  
Immunofluorescence Analysis ◽  
Protein P53 ◽  
Damage Response
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