Circadian Clock- and Transcription-controlled Genome-wide Excision Repair of UV Damage in Arabidopsis
Ontology highlight
ABSTRACT: We used the recently developed Excision Repair-sequencing (XR-seq) method to study genome-wide repair of UV-induced DNA damage in Arabidopsis. We found that the repair of cyclobutane pyrimidine dimers for a large fraction of the genome is controlled by the joint actions of the circadian clock and transcription by RNA polymerase II. Arabidopsis has a relatively compact genome, and a large fraction of the genes are controlled by the circadian clock. Our data on the interface of these two global regulatory systems reveal very strong repair preference of the transcribed strands of Arabidopsis genes, 10 to 30% of which are circadian time-dependent. Thus, throughout the day, Arabidopsis exhibits enormous dynamic range in repair to cope with exposure to sunlight.
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 recently developed a high-resolution genome wide assay for mapping DNA excision repair named eXcision Repair-sequencing (XR-seq) (GEO accession: GSE67941) We have now used this assay to assay the effect of chromatin state on DNA repair. Here we report the results of a time-course of the repair of the UV induced damages cyclobutane pyrimidine dimers (CPDs) and (6-4) pyrimidine-pyrimidone photoproducts [(6-4)PPs] in normal human skin fibroblasts. Comparison of this data to histone modification and DNA-seq maps (ENCODE) revealed initial repair of both damages is enriched in open and active chromatin states, whereas repair in heterochromatic and repressed chromatin states is relatively low and persists to later time points. We performed XR-seq for two types of UV induced damages (CPD and (6-4)PP) at multiple time points after UV irradiation, in normal NHF1, and CS-B (CS1ANps3g2, GM16095) fibroblast cell lines. Two biological replicates were performed for each experiment in which independent independent cell populations were UV treated and subjected to XR-seq. For assaying CPD repair, cells were irradiated with 10J/m2 and for assaying (6-4)PP cells were irradiated with 20J/m2. Raw data for the 1h time points of (6-4)PP repair are the same as in GEO accession GSE67941).
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:We recently developed a high-resolution genome wide assay for mapping DNA excision repair named eXcision Repair-sequencing (XR-seq) (GEO accession: GSE67941) We have now used this assay to assay the effect of chromatin state on DNA repair. Here we report the results of a time-course of the repair of the UV induced damages cyclobutane pyrimidine dimers (CPDs) and (6-4) pyrimidine-pyrimidone photoproducts [(6-4)PPs] in normal human skin fibroblasts. Comparison of this data to histone modification and DNA-seq maps (ENCODE) revealed initial repair of both damages is enriched in open and active chromatin states, whereas repair in heterochromatic and repressed chromatin states is relatively low and persists to later time points.
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 (CPD) photoproducts in the Caenorhabditis elegans (C. elegans) genome.
Project description:Cisplatin is the most commonly used chemotherapeutic drug for treating solid tumors. However, its toxicity and the innate or acquired resistance of cancer cells to the drug limit its usefulness. Cisplatin kills cells by forming cisplatin-DNA adducts, most commonly in the form of Pt-d(GpG) diadduct. We recently showed that repair of this adduct within 2 hours following injection is controlled by two circadian programs: (1) The circadian clock controls transcription of 2000 genes in mouse liver and thereby controls repair of the transcribed strand of these genes via transcription coupled repair in a rhythmic fashion unique to each gene’s phase of transcription. (2) The basal excision repair activity itself is controlled by the circadian clock with a single phase at which the repair of the non-transcribed strand and the rest of the genome take place. Here, we have followed the repair kinetic for long periods genome-wide both globally and at single nucleotide resolution by the Excision Repair-sequencing (XR-seq) method to gain further insight into cisplatin DNA damage and repair with the aim of improving the therapeutic index of the drug. Our data show that transcription-driven repair is complete after two days, while completion of basal repair of nontranscribed strands, silent genes and intergenic regions requires weeks. In rhythmically controlled genes, oscillations of transcribed repair are observed up to 2 days post-injection, and in both constitutively transcribed and rhythmic genes, we see a trend in template strand repair with time from the 5’to 3’ end. These findings add to the complexity of circadian- and transcription-dependent and -independent control of repair exhibited by this model organism in response to cisplatin.
Project description:Cisplatin is the most commonly used chemotherapeutic drug for treating solid tumors. However, its toxicity and the innate or acquired resistance of cancer cells to the drug limit its usefulness. Cisplatin kills cells by forming cisplatin-DNA adducts, most commonly in the form of Pt-d(GpG) diadduct. We recently showed that repair of this adduct within 2 hours following injection is controlled by two circadian programs: (1) The circadian clock controls transcription of 2000 genes in mouse liver and thereby controls repair of the transcribed strand of these genes via transcription coupled repair in a rhythmic fashion unique to each gene’s phase of transcription. (2) The basal excision repair activity itself is controlled by the circadian clock with a single phase at which the repair of the non-transcribed strand and the rest of the genome take place. Here, we have followed the repair kinetic for long periods genome-wide both globally and at single nucleotide resolution by the Excision Repair-sequencing (XR-seq) method to gain further insight into cisplatin DNA damage and repair with the aim of improving the therapeutic index of the drug. Our data show that transcription-driven repair is complete after two days, while completion of basal repair of nontranscribed strands, silent genes and intergenic regions requires weeks. In rhythmically controlled genes, oscillations of transcribed repair are observed up to 2 days post-injection, and in both constitutively transcribed and rhythmic genes, we see a trend in template strand repair with time from the 5’to 3’ end. These findings add to the complexity of circadian- and transcription-dependent and -independent control of repair exhibited by this model organism in response to cisplatin.
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 (CPD) photoproducts in the Caenorhabditis elegans (C. elegans) genome. We focus on the C. elegans ortholog of the human XPC-deficient strain (xpc-1) and its exclusive use of transcription-coupled repair. We provide evidence demonstrating the utility of xpc-1 XR-seq as a remarkable tool for detecting nascent transcription and identifying new transcripts. The integration of epigenetic markers, chromatin states, and non-coding RNA annotations supports the robust detection of intergenic nascent transcription by XR-seq. Overall, our results provide a comprehensive view of the transcription-coupled repair landscape in C. elegans, highlighting their potential contributions to our understanding of DNA repair mechanisms and non-coding RNA biology.