scholarly journals hSSB2 (NABP1) is required for the recruitment of RPA during the cellular response to DNA UV damage

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Didier Boucher ◽  
Ruvini Kariawasam ◽  
Joshua Burgess ◽  
Adrian Gimenez ◽  
Tristan E. Ocampo ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cellular Response ◽  
Excision Repair ◽  
Protein A ◽  
Ultraviolet B ◽  
Repair System ◽  
Uvb Radiation ◽  
Exogenous Dna

AbstractMaintenance of genomic stability is critical to prevent diseases such as cancer. As such, eukaryotic cells have multiple pathways to efficiently detect, signal and repair DNA damage. One common form of exogenous DNA damage comes from ultraviolet B (UVB) radiation. UVB generates cyclobutane pyrimidine dimers (CPD) that must be rapidly detected and repaired to maintain the genetic code. The nucleotide excision repair (NER) pathway is the main repair system for this type of DNA damage. Here, we determined the role of the human Single-Stranded DNA Binding protein 2, hSSB2, in the response to UVB exposure. We demonstrate that hSSB2 levels increase in vitro and in vivo after UVB irradiation and that hSSB2 rapidly binds to chromatin. Depletion of hSSB2 results in significantly decreased Replication Protein A (RPA32) phosphorylation and impaired RPA32 localisation to the site of UV-induced DNA damage. Delayed recruitment of NER protein Xeroderma Pigmentosum group C (XPC) was also observed, leading to increased cellular sensitivity to UVB. Finally, hSSB2 was shown to have affinity for single-strand DNA containing a single CPD and for duplex DNA with a two-base mismatch mimicking a CPD moiety. Altogether our data demonstrate that hSSB2 is involved in the cellular response to UV exposure.

scholarly journals Antagonism of Ultraviolet-Light Mutagenesis by the Methyl-Directed Mismatch-Repair System of Escherichia coli

Genetics ◽  
2000 ◽  
Vol 154 (2) ◽  
pp. 503-512 ◽  
Author(s):  
Hongbo Liu ◽  
Stephen R Hewitt ◽  
John B Hays
Keyword(s):  
Escherichia Coli ◽  
Mismatch Repair ◽  
Excision Repair ◽  
Spontaneous Mutation ◽  
Repair System ◽  
Uv Mutagenesis ◽  
Repair Protein ◽  
Mismatch Repair System

Abstract Previous studies have demonstrated that the Escherichia coli MutHLS mismatch-repair system can process UV-irradiated DNA in vivo and that the human MSH2·MSH6 mismatch-repair protein binds more strongly in vitro to photoproduct/base mismatches than to “matched” photoproducts in DNA. We tested the hypothesis that mismatch repair directed against incorrect bases opposite photoproducts might reduce UV mutagenesis, using two alleles at E. coli lacZ codon 461, which revert, respectively, via CCC → CTC and CTT → CTC transitions. F′ lacZ targets were mated from mut+ donors into mutH, mutL, or mutS recipients, once cells were at substantial densities, to minimize spontaneous mutation prior to irradiation. In umu+ mut+ recipients, a range of UV fluences induced lac+ revertant frequencies of 4–25 × 10−8; these frequencies were consistently 2-fold higher in mutH, mutL, or mutS recipients. Since this effect on mutation frequency was unaltered by an Mfd− defect, it appears not to involve transcription-coupled excision repair. In mut+ umuC122::Tn5 bacteria, UV mutagenesis (at 60 J/m2) was very low, but mutH or mutL or mutS mutations increased reversion of both lacZ alleles roughly 25-fold, to 5–10 × 10−8. Thus, at UV doses too low to induce SOS functions, such as Umu2′D, most incorrect bases opposite occasional photoproducts may be removed by mismatch repair, whereas in heavily irradiated (SOS-induced) cells, mismatch repair may only correct some photoproduct/base mismatches, so UV mutagenesis remains substantial.

scholarly journals UV-induced Hyperphosphorylation of Replication Protein A Depends on DNA Replication and Expression of ATM Protein

2001 ◽  
Vol 12 (5) ◽  
pp. 1199-1213 ◽  
Author(s):  
Gregory G. Oakley ◽  
Lisa I. Loberg ◽  
Jiaqin Yao ◽  
Mary A. Risinger ◽  
Remy L. Yunker ◽  
...  
Keyword(s):  
Dna Replication ◽  
Uv Radiation ◽  
Excision Repair ◽  
Genetic Disorder ◽  
Protein A ◽  
Dna Recombination ◽  
Delayed Response ◽  
Replication Intermediates

Exposure to DNA-damaging agents triggers signal transduction pathways that are thought to play a role in maintenance of genomic stability. A key protein in the cellular processes of nucleotide excision repair, DNA recombination, and DNA double-strand break repair is the single-stranded DNA binding protein, RPA. We showed previously that the p34 subunit of RPA becomes hyperphosphorylated as a delayed response (4–8 h) to UV radiation (10–30 J/m2). Here we show that UV-induced RPA-p34 hyperphosphorylation depends on expression of ATM, the product of the gene mutated in the human genetic disorder ataxia telangiectasia (A-T). UV-induced RPA-p34 hyperphosphorylation was not observed in A-T cells, but this response was restored by ATM expression. Furthermore, purified ATM kinase phosphorylates the p34 subunit of RPA complex in vitro at many of the same sites that are phosphorylated in vivo after UV radiation. Induction of this DNA damage response was also dependent on DNA replication; inhibition of DNA replication by aphidicolin prevented induction of RPA-p34 hyperphosphorylation by UV radiation. We postulate that this pathway is triggered by the accumulation of aberrant DNA replication intermediates, resulting from DNA replication fork blockage by UV photoproducts. Further, we suggest that RPA-p34 is hyperphosphorylated as a participant in the recombinational postreplication repair of these replication products. Successful resolution of these replication intermediates reduces the accumulation of chromosomal aberrations that would otherwise occur as a consequence of UV radiation.

scholarly journals DDB2, an Essential Mediator of Premature Senescence

2010 ◽  
Vol 30 (11) ◽  
pp. 2681-2692 ◽  
Author(s):  
Nilotpal Roy ◽  
Tanya Stoyanova ◽  
Carmen Dominguez-Brauer ◽  
Hyun Jung Park ◽  
Srilata Bagchi ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Excision Repair ◽  
Culture Shock ◽  
Premature Senescence ◽  
Antioxidant Genes ◽  
Repair Protein ◽  
High Level

ABSTRACT Reactive oxygen species (ROS) is critical for premature senescence, a process significant in tumor suppression and cancer therapy. Here, we reveal a novel function of the nucleotide excision repair protein DDB2 in the accumulation of ROS in a manner that is essential for premature senescence. DDB2-deficient cells fail to undergo premature senescence induced by culture shock, exogenous oxidative stress, oncogenic stress, or DNA damage. These cells do not accumulate ROS following DNA damage. The lack of ROS accumulation in DDB2 deficiency results from high-level expression of the antioxidant genes in vitro and in vivo. DDB2 represses antioxidant genes by recruiting Cul4A and Suv39h and by increasing histone-H3K9 trimethylation. Moreover, expression of DDB2 also is induced by ROS. Together, our results show that, upon oxidative stress, DDB2 functions in a positive feedback loop by repressing the antioxidant genes to cause persistent accumulation of ROS and induce premature senescence.

scholarly journals Nuclear Accumulation of LAP1:TRF2 Complex during DNA Damage Response Uncovers a Novel Role for LAP1

Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1804
Author(s):  
Cátia D. Pereira ◽  
Filipa Martins ◽  
Mariana Santos ◽  
Thorsten Müeller ◽  
Odete A. B. da Cruz e Silva ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Cellular Response ◽  
Nuclear Accumulation ◽  
Protein Levels ◽  
Dna Damaging Agents ◽  
Physiological Properties ◽  
Damage Response

Lamina-associated polypeptide 1 (LAP1) is a nuclear envelope (NE) protein whose function remains poorly characterized. In a recent LAP1 protein interactome study, a putative regulatory role in the DNA damage response (DDR) has emerged and telomeric repeat-binding factor 2 (TRF2), a protein intimately associated with this signaling pathway, was among the list of LAP1 interactors. To gain insights into LAP1′s physiological properties, the interaction with TRF2 in human cells exposed to DNA-damaging agents was investigated. The direct LAP1:TRF2 binding was validated in vitro by blot overlay and in vivo by co-immunoprecipitation after hydrogen peroxide and bleomycin treatments. The regulation of this protein interaction by LAP1 phosphorylation was demonstrated by co-immunoprecipitation and mass spectrometry following okadaic acid exposure. The involvement of LAP1 and TRF2 in the DDR was confirmed by their increased nuclear protein levels after bleomycin treatment, evaluated by immunoblotting, as well as by their co-localization with DDR factors at the NE and within the nucleoplasm, assessed by immunocytochemistry. Effectively, we showed that the LAP1:TRF2 complex is established during a cellular response against DNA damage. This work proposes a novel functional role for LAP1 in the DDR, revealing a potential biological mechanism that may be disrupted in LAP1-associated pathologies.

scholarly journals UvrD Participation in Nucleotide Excision Repair Is Required for the Recovery of DNA Synthesis following UV-Induced Damage inEscherichia coli

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Kelley N. Newton ◽  
Charmain T. Courcelle ◽  
Justin Courcelle
Keyword(s):  
Dna Damage ◽  
Dna Synthesis ◽  
Nucleotide Excision Repair ◽  
Excision Repair ◽  
Dna Helicase ◽  
Replication Forks ◽  
Nucleotide Excision ◽  
Fork Regression

UvrD is a DNA helicase that participates in nucleotide excision repair and several replication-associated processes, including methyl-directed mismatch repair and recombination. UvrD is capable of displacing oligonucleotides from synthetic forked DNA structuresin vitroand is essential for viability in the absence of Rep, a helicase associated with processing replication forks. These observations have led others to propose that UvrD may promote fork regression and facilitate resetting of the replication fork following arrest. However, the molecular activity of UvrD at replication forksin vivohas not been directly examined. In this study, we characterized the role UvrD has in processing and restoring replication forks following arrest by UV-induced DNA damage. We show that UvrD is required for DNA synthesis to recover. However, in the absence of UvrD, the displacement and partial degradation of the nascent DNA at the arrested fork occur normally. In addition, damage-induced replication intermediates persist and accumulate inuvrDmutants in a manner that is similar to that observed in other nucleotide excision repair mutants. These data indicate that, following arrest by DNA damage, UvrD is not required to catalyze fork regressionin vivoand suggest that the failure ofuvrDmutants to restore DNA synthesis following UV-induced arrest relates to its role in nucleotide excision repair.

scholarly journals UV radiation-induced SUMOylation of DDB2 regulates nucleotide excision repair

2017 ◽  
Vol 38 (10) ◽  
pp. 976-985 ◽  
Author(s):  
Chunhua Han ◽  
Ran Zhao ◽  
John Kroger ◽  
Jinshan He ◽  
Gulzar Wani ◽  
...  
Keyword(s):  
Dna Damage ◽  
Nucleotide Excision Repair ◽  
Uv Radiation ◽  
Uv Irradiation ◽  
Excision Repair ◽  
26S Proteasome ◽  
Cell Extracts ◽  
Nucleotide Excision

Abstract Subunit 2 of DNA damage-binding protein complex (DDB2) is an early sensor of nucleotide excision repair (NER) pathway for eliminating DNA damage induced by UV radiation (UVR) and cisplatin treatments of mammalian cells. DDB2 is modified by ubiquitin and poly(ADP-ribose) (PAR) in response to UVR, and these modifications play a crucial role in regulating NER. Here, using immuno-analysis of irradiated cell extracts, we have identified multiple post-irradiation modifications of DDB2 protein. Interestingly, although the DNA lesions induced by both UVR and cisplatin are corrected by NER, only the UV irradiation, but not the cisplatin treatment, induces any discernable DDB2 modifications. We, for the first time, show that the appearance of UVR-induced DDB2 modifications depend on the binding of DDB2 to the damaged chromatin and the participation of functionally active 26S proteasome. The in vitro and in vivo analysis revealed that SUMO-1 conjugations comprise a significant portion of these UVR-induced DDB2 modifications. Mapping of SUMO-modified sites demonstrated that UVR-induced SUMOylation occurs on Lys-309 residue of DDB2 protein. Mutation of Lys-309 to Arg-309 diminished the DDB2 SUMOylation observable both in vitro and in vivo. Moreover, K309R mutated DDB2 lost its function of recruiting XPC to the DNA damage sites, as well as the ability to repair cyclobutane pyrimidine dimers following cellular UV irradiation. Taken together, our results indicate that DDB2 is modified by SUMOylation upon UV irradiation, and this post-translational modification plays an important role in the initial recognition and processing of UVR-induced DNA damage occurring within the context of chromatin.

scholarly journals Almond Consumption Increased UVB Resistance in Healthy Asian Women

2021 ◽  
Vol 5 (Supplement_2) ◽  
pp. 319-319
Author(s):  
Susanne Henning ◽  
Jason Li ◽  
Gail Thames ◽  
Omar Bari ◽  
Patrick Tran ◽  
...  
Keyword(s):  
Skin Aging ◽  
Ultraviolet B ◽  
In Vivo Studies ◽  
Asian Women ◽  
Skin Extract ◽  
Uvb Radiation ◽  
Facial Skin ◽  
Uvb Exposure

Abstract Objectives Almonds are a rich source of phenolic and polyphenolic compounds, which have antioxidant activity. In vitro and in vivo studies have demonstrated that topical application of almond oil and almond skin extract reduces UVB-induced photoaging. Ultraviolet-B (UVB) protection by oral almond consumption has not been previously studied in humans. It was the objective to investigate whether oral almond consumption can increase resistance to UVB radiation and reduce skin aging in healthy Asian women. Methods Thirty-nine female participants (18–45 years) with Fitzpatrick skin type II-IV were randomly assigned to consume either 1.5 oz of almonds or 1.8 oz of pretzels daily for 12 weeks. Minimal erythema dose (MED) was determined using a standardized protocol, which determined the minimal radiation inducing erythema on the inner arm 24 hours following UVB exposure. Facial skin texture was evaluated by two dermatologists using the Clinician's Erythema Assessment scale and Allergan Roughness scale. Facial melanin index, hydration, sebum, and erythema were determined using a cutometer. Results Women who consumed almonds, experienced a significant increase in MED from 415 ± 64 to 487 ± 59 (18.7 ± 19.2%, P = 0.006) from baseline to week 12 compared to women in the pretzel group from 415 ± 67 to 421 ± 67 (1.8 ± 11.1%). The exposure time to reach minimal erythema was also increased significantly in the almond group from 160 ± 23 to 187 ± 25 (17.5 ± 22.2%) compared to the pretzel group from 165 ± 27 to 166 ± 25 (1.7 ± 14%) (p=0.026). There were no differences noted between the groups consuming almonds versus pretzels in Allergan roughness, melanin, hydration, or sebum on facial skin. Conclusions Our findings suggest that daily oral almond consumption may lead to enhanced protection from UVB photodamage by increasing the MED. Protection from other UV radiation was not tested and therefore almond consumption will not replace other methods of sun protection such as application of sunscreen or wearing protective closing. Funding Sources Almond Board of California.

Exploring DNA damage responses in human cells with recombinant adenoviral vectors

2007 ◽  
Vol 26 (11) ◽  
pp. 899-906
Author(s):  
Melissa G. Armelini ◽  
Keronninn M. Lima-Bessa ◽  
Maria Carolina N. Marchetto ◽  
Alysson R. Muotri ◽  
Vanessa Chiganças ◽  
...  
Keyword(s):  
Dna Damage ◽  
Mammalian Cells ◽  
Excision Repair ◽  
Adenoviral Vectors ◽  
Dna Lesions ◽  
Human Cells ◽  
Polymerase Eta ◽  
Cell Culture Systems

Recombinant adenoviral vectors provide efficient means for gene transduction in mammalian cells in vitro and in vivo. We are currently using these vectors to transduce DNA repair genes into repair deficient cells, derived from xeroderma pigmentosum (XP) patients. XP is an autosomal syndrome characterized by a high frequency of skin tumors, especially in areas exposed to sunlight, and, occasionally, developmental and neurological abnormalities. XP cells are deficient in nucleotide excision repair (affecting one of the seven known XP genes, xpa to xpg) or in DNA replication of DNA lesions (affecting DNA polymerase eta, xpv). The adenovirus approach allows the investigation of different consequences of DNA lesions in cell genomes. Adenoviral vectors carrying several xp and photolyases genes have been constructed and successfully tested in cell culture systems and in vivo directly in the skin of knockout model mice. This review summarizes these recent data and proposes the use of recombinant adenoviruses as tools to investigate the mechanisms that provide protection against DNA damage in human cells, as well as to better understand the higher predisposition of XP patients to cancer. Human & Experimental Toxicology (2007) 26, 899—906

Sign in / Sign up

Export Citation Format

Share Document