Project description:We report the application of single-molecule-based sequencing technology (XR-seq) for high-throughput profiling of nucleotide excision repair in Drosophila four developmental stages and S2 cells. By obtaining over six billion bases of sequence from UV and cisplatin damage antibodies immunoprecipitated excision DNA, we generated genome-wide nucleotide excision repair maps of Drosophila Embryo, Larva, Pupa , two gender of adults and S2 cells . We find that Drosophila performs transcription-coupled repair (TCR) at all its developmental stages. S2 cell carry out TCR response to both UV and Cisplatin damage. Finally, we show that XPC repair factor is required for both global and transcription-coupled repair in Drosophila. This study provides the mechanism of nucleotide excision repair of Drosophila in vivo and vitro response to UV and Cisplatin damage.
Project description:Nucleosomes are a significant barrier to the repair of UV damage because they impede damage recognition by nucleotide excision repair (NER). The RSC chromatin remodeler functions in cells to promote DNA access by moving or evicting nucleosomes and has been linked to NER in yeast. Here, we report genome-wide repair maps of UV-induced cyclobutane pyrimidine dimers (CPDs) in yeast cells lacking Rsc2.
Project description:We developed a method for genome-wide mapping of DNA excision repair named XR-seq (eXcision Repair-seq). Human nucleotide excision repair generates two incisions surrounding the site of damage, creating a ~30-mer. In XR-seq, this fragment is isolated and subjected to high-throughput sequencing. We used XR-seq to produce stranded, nucleotide-resolution maps of repair of two UV-induced DNA damages in human cells, cyclobutane pyrimidine dimers (CPDs) and (6-4) pyrimidine-pyrimidone photoproducts ((6-4)PPs). In wild-type cells, CPD repair was highly associated with transcription, specifically with the template strand. Experiments in cells defective in either transcription-coupled excision repair or general excision repair isolated the contribution of each pathway to the overall repair pattern, and showed that transcription-coupled repair of both photoproducts occurs exclusively on the template strand. XR-seq maps capture transcription-coupled repair at sites of divergent gene promoters and bi-directional eRNA production at enhancers. XR-seq data also uncovered the repair characteristics and novel sequence preferences of CPDs and (6-4)PPs. XR-seq and the resulting repair maps will facilitate studies of the effects of genomic location, chromatin context, transcription, and replication on DNA repair in human cells. We have performed XR-seq for two types of UV-induced damages (CPD and (6-4)PP) in three different cell lines: NHF1, XP-C (XP4PA-SV-EB, GM15983)), and CS-B (CS1ANps3g2, GM16095). Two biological replicates were performed for each experiment, in which independent cell populations were UV treated and subjected to XR-seq.
Project description:We developed a method for genome-wide mapping of DNA excision repair named XR-seq (eXcision Repair-seq). Human nucleotide excision repair generates two incisions surrounding the site of damage, creating a ~30-mer. In XR-seq, this fragment is isolated and subjected to high-throughput sequencing. We used XR-seq to produce stranded, nucleotide-resolution maps of repair of two UV-induced DNA damages in human cells, cyclobutane pyrimidine dimers (CPDs) and (6-4) pyrimidine-pyrimidone photoproducts ((6-4)PPs). In wild-type cells, CPD repair was highly associated with transcription, specifically with the template strand. Experiments in cells defective in either transcription-coupled excision repair or general excision repair isolated the contribution of each pathway to the overall repair pattern, and showed that transcription-coupled repair of both photoproducts occurs exclusively on the template strand. XR-seq maps capture transcription-coupled repair at sites of divergent gene promoters and bi-directional eRNA production at enhancers. XR-seq data also uncovered the repair characteristics and novel sequence preferences of CPDs and (6-4)PPs. XR-seq and the resulting repair maps will facilitate studies of the effects of genomic location, chromatin context, transcription, and replication on DNA repair in human cells.
Project description:Repair of UV damage from the transcribed strand (TS) of yeast genes is rapid due to the transcription coupled nucleotide excision repair (TC-NER) pathway. TC-NER is triggered when RNA polymerase stalls at UV damage, such as a UV-induced cyclobutane pyrimidine dimer (CPD). During transcription, the histone methyltransferase Set2 methylates histone H3K36, but it is not known if Set2 regulates TC-NER. Here, we report genome-wide repair maps of UV-induced cyclobutane pyrimidine dimers (CPDs) in yeast cells lacking Set2.
Project description:We have adapted the eXcision Repair-sequencing (XR-seq) method to generate single-nucleotide resolution dynamic repair maps of UV-induced cyclobutane pyrimidine dimers (CPDs) and (6-4) pyrimidine-pyrimidone photoproducts [(6-4)PPs] in the Saccharomyces cerevisiae genome. We find that these photoproducts are removed from the genome primarily by incisions 13-18 nucleotides 5’ and 6-7 nucleotides 3’ to the UV damage that generate 21-27 nt-long excision products. Analyses of the excision repair kinetics both in single genes and at the genome-wide level reveal strong transcription-coupled repair of the transcribed strand (TS) at early time points followed by predominantly non-transcribed strand (NTS) repair at later stages. We have also characterized the excision repair level as a function of transcription level. The availability of high-resolution and dynamic repair maps should aid in future repair and mutagenesis studies in this model organism.
Project description:We characterized the role of H3K36 methylation in regulating repair of UV damage from the transcribed strand (TS) of yeast genes by the transcription coupled nucleotide excision repair (TC-NER) pathway. TC-NER is triggered when RNA polymerase stalls at UV damage, such as a UV-induced cyclobutane pyrimidine dimer (CPD). During transcription, the histone methyltransferase Set2 methylates histone H3K36, but it is not known if H3K36 methylation regulates TC-NER. Here, we report genome-wide repair maps of UV-induced cyclobutane pyrimidine dimers (CPDs) in yeast cells containing mutants in histone H3K36 (or set2).
Project description:Embryonic stem cells can self-renew and differentiate, holding great promise for regenerative medicine. They also employ multiple mechanisms to preserve the integrity of their genomes. Nucleotide excision repair, a versatile repair mechanism, removes bulky DNA adducts from the genome. However, the dynamics of the capacity of nucleotide excision repair during stem cell differentiation remain unclear. Here, using immunoslot blot assay, we measured repair rates of UV-induced DNA damage during differentiation of human embryonic carcinoma (NTERA-2) cells into neurons and muscle cells. Our results revealed that the capacity of nucleotide excision repair increases as cell differentiation progresses. We also found that inhibition of the apoptotic signaling pathway has no effect on nucleotide excision repair capacity. Furthermore, RNA-seq-based transcriptomic analysis indicated that expression levels of four core repair factors, xeroderma pigmentosum (XP) complementation group A (XPA), XPC, XPG, and XPF-ERCC1, are progressively up-regulated during differentiation, but not those of replication protein A (RPA) and transcription factor IIH (TFIIH). Together, our findings reveal that increase of nucleotide excision repair capacity accompanies cell differentiation, supported by the up-regulated transcription of genes encoding DNA repair enzymes during differentiation of two distinct cell lineages.
Project description:Genetic alterations in members of the nucleotide excision repair (NER) pathway are present in a wide spectrum of cancers, but specific treatment options for this patient population are scarce. Here, we show occurrence of putative damaging germline and somatic alterations in NER genes in up to 10% of patients within certain cancer types across a large set of cancers and explored the potential therapeutic role of irofulven for patients with hypomorphic mutations in nucleotide excision repair genes. Gene-edited isogenic pairs of wildtype and mutant ERCC2 or ERCC3 cell lines were used to assess response to irofulven. Both in vitro and in vivo studies showed significantly enhanced irofulven sensitivity in cells harboring specific clinically observed heterozygous mutations in ERCC2 or ERCC3. Sensitivity of NER mutants to irofulven was greater than to the current standard of care agent cisplatin. Hypomorphic ERCC2/3 mutant cells had an impaired ability to repair irofulven induced DNA damage. Transcriptomic profiling of the tumor tissues suggested co-dependencies between DNA repair pathways, indicating a potential benefit of combination therapies, which were confirmed by in vitro studies. The present study provides a molecularly targeted, pre-clinical approach to cancers with mutations in nucleotide excision repair pathway genes, demonstrating preferential sensitivity to the drug irofulven alone, or in combination with other agents.