Project description:The aim of this analysis is to identify the difference between interaction partners of MRG15 wild type and Chromodomain and MRG domain mutants upon UV irradiation. Therefore, MRG15 wild type and mutants (N-terminal FLAG tag) were overexpressed in U2OS cells. After UV irradiation, immunoprecipitation of the constructs was performed using FLAG M2 affinity gel. The constructs were eluted from the beads with 3xFLAG peptide.
Project description:To investigate the mechanistic effects of UV irradiation on pea seedlings at the protein level, proteomic analyses were performed on pea seedlings irradiated daily with 0 and 10 min UV-B.
Project description:Cockayne syndrome B (CSB) protein is a member of the SWI/SNF family and has DNA-dependent ATPase and ATP-dependent chromatin remodeling activities. The CSB protein is missing or altered in CS-B cells. CS-B cells are hypersensitive to UV light and defective in transcription-coupled DNA repair (TCR). TCR efficiently removes a variety of lesions from the transcribed strand of active genes. It has been shown that lesions specifically in the transcribed strand of active genes trigger the induction of apoptosis following UV irradiation. Several DNA damage signaling cascades, including the ATR/Chk1, p38 kinase, p53, and jun N-terminal kinase pathways are activated following UV irradiation. However, the role of TCR in cellular global transcriptional responses to UV irradiation remains to be elucidated. Using oligonucleotide microarray technology, we analyzed the time course of responses of CS-B cells (CS-B) and CS-B cells complemented with wild-type CSB cDNA (CS-B wt). Keywords: UV response, time course, disease state analysis
Project description:We conducted transcript profiling and metabolome profiling induced by UV irradiation in grape berry skin. Transcriptome analysis was carried out with genome-wide microarray and two hundred thirty eight genes were more than 5-fold up-regulated by UV irradiation. The enrichment analysis showed GO terms including stilbene synthase (STS) gene. Moreover, the principal component analysis (PCA) of metabolome analysis showed a compound, identified resveratrol, accumulated in grape berry skin specifically. Our result clearly shows that UV irradiation induced only accumulation of resveratrol and its analogues but did not induce accumulation of the other phenolic compounds.
Project description:LAP-35 and SK-N_MC cells were treated with 10 J/m2 UV light versus untreated Alternative pre-mRNA processing plays a key role in the response to DNA damage as well as in neoplastic transformation. We found that two Ewing Sarcoma (ES) cell lines exhibit different sensitivity to UV light irradiation, with SK-N-MC cells being more sensitive than LAP-35 cells. RNA profiling during the response to low doses of UV light irradiation revealed genes differentially regulated between the two cell lines. In particular, UV light irradiation induced a novel isoform of the RNA helicase DHX9 which is targeted to nonsense-mediated decay (NMD) and therefore causes down-regulation of DHX9 in SK-N-MC cells, but not in LAP-35 cells. DHX9 protein forms a complex with RNA polymerase II (RNAPII) and EWS-FLI1 to enhance transcription, and we found that down-regulation of DHX9 by UV light irradiation in SK-N-MC cells impairs the recruitment of EWS-FLI1 to target genes and increases sensitivity to DNA damage. Notably, sensitivity of SK-N-MC cells to irradiation correlated with enhanced phosphorylation and decreased processivity of RNAPII upon irradiation, which in turn causes inclusion of the novel DHX9 exon in SK-N-MC cells exposed to UV light, an observation that could be recapitulated in LAP35 cells by pharmacological reduction of RNAPII processivity. Our data suggest that EWS-FLI1 oncogene activity could be targeted by modulation of DHX9 gene expression.
Project description:Somatic mutations are highly enriched at transcription factor (TF) binding sites, with the strongest trend being observed for ultraviolet light (UV)-induced mutations in melanomas. One of the main mechanisms proposed for this hyper-mutation pattern is the inefficient repair of UV lesions within TF-binding sites, caused by competition between TFs bound to these lesions and the DNA repair proteins that must recognize the lesions to initiate repair. However, TF binding to UV-irradiated DNA is poorly characterized, and it is unclear whether TFs maintain specificity for their DNA sites after UV exposure. We developed UV-Bind, a high-throughput approach to investigate the impact of UV irradiation on protein-DNA binding specificity. We applied UV-Bind to ten TFs from eight structural families, and found that UV lesions significantly altered the DNA-binding preferences of all TFs tested. The main effect was a decrease in binding specificity, but the precise effects and their magnitude differ across factors. Importantly, we found that despite the overall reduction in DNA-binding specificity in the presence of UV lesions, TFs can still compete with repair proteins for lesion recognition, in a manner consistent with their specificity for UV-irradiated DNA. In addition, for a subset of TFs we identified a surprising but reproducible effect at certain non-consensus DNA sequences, where UV irradiation leads to a high increase in the level of TF binding. These changes in DNA-binding specificity after UV irradiation, at both consensus and non-consensus sites, have important implications for the regulatory and mutagenic roles of TFs in the cell.
Project description:Somatic mutations are highly enriched at transcription factor (TF) binding sites, with the strongest trend being observed for ultraviolet light (UV)-induced mutations in melanomas. One of the main mechanisms proposed for this hyper-mutation pattern is the inefficient repair of UV lesions within TF-binding sites, caused by competition between TFs bound to these lesions and the DNA repair proteins that must recognize the lesions to initiate repair. However, TF binding to UV-irradiated DNA is poorly characterized, and it is unclear whether TFs maintain specificity for their DNA sites after UV exposure. We developed UV-Bind, a high-throughput approach to investigate the impact of UV irradiation on protein-DNA binding specificity. We applied UV-Bind to ten TFs from eight structural families, and found that UV lesions significantly altered the DNA-binding preferences of all TFs tested. The main effect was a decrease in binding specificity, but the precise effects and their magnitude differ across factors. Importantly, we found that despite the overall reduction in DNA-binding specificity in the presence of UV lesions, TFs can still compete with repair proteins for lesion recognition, in a manner consistent with their specificity for UV-irradiated DNA. In addition, for a subset of TFs we identified a surprising but reproducible effect at certain non-consensus DNA sequences, where UV irradiation leads to a high increase in the level of TF binding. These changes in DNA-binding specificity after UV irradiation, at both consensus and non-consensus sites, have important implications for the regulatory and mutagenic roles of TFs in the cell.
Project description:Somatic mutations are highly enriched at transcription factor (TF) binding sites, with the strongest trend being observed for ultraviolet light (UV)-induced mutations in melanomas. One of the main mechanisms proposed for this hyper-mutation pattern is the inefficient repair of UV lesions within TF-binding sites, caused by competition between TFs bound to these lesions and the DNA repair proteins that must recognize the lesions to initiate repair. However, TF binding to UV-irradiated DNA is poorly characterized, and it is unclear whether TFs maintain specificity for their DNA sites after UV exposure. We developed UV-Bind, a high-throughput approach to investigate the impact of UV irradiation on protein-DNA binding specificity. We applied UV-Bind to ten TFs from eight structural families, and found that UV lesions significantly altered the DNA-binding preferences of all TFs tested. The main effect was a decrease in binding specificity, but the precise effects and their magnitude differ across factors. Importantly, we found that despite the overall reduction in DNA-binding specificity in the presence of UV lesions, TFs can still compete with repair proteins for lesion recognition, in a manner consistent with their specificity for UV-irradiated DNA. In addition, for a subset of TFs we identified a surprising but reproducible effect at certain non-consensus DNA sequences, where UV irradiation leads to a high increase in the level of TF binding. These changes in DNA-binding specificity after UV irradiation, at both consensus and non-consensus sites, have important implications for the regulatory and mutagenic roles of TFs in the cell.
Project description:Somatic mutations are highly enriched at transcription factor (TF) binding sites, with the strongest trend being observed for ultraviolet light (UV)-induced mutations in melanomas. One of the main mechanisms proposed for this hyper-mutation pattern is the inefficient repair of UV lesions within TF-binding sites, caused by competition between TFs bound to these lesions and the DNA repair proteins that must recognize the lesions to initiate repair. However, TF binding to UV-irradiated DNA is poorly characterized, and it is unclear whether TFs maintain specificity for their DNA sites after UV exposure. We developed UV-Bind, a high-throughput approach to investigate the impact of UV irradiation on protein-DNA binding specificity. We applied UV-Bind to ten TFs from eight structural families, and found that UV lesions significantly altered the DNA-binding preferences of all TFs tested. The main effect was a decrease in binding specificity, but the precise effects and their magnitude differ across factors. Importantly, we found that despite the overall reduction in DNA-binding specificity in the presence of UV lesions, TFs can still compete with repair proteins for lesion recognition, in a manner consistent with their specificity for UV-irradiated DNA. In addition, for a subset of TFs we identified a surprising but reproducible effect at certain non-consensus DNA sequences, where UV irradiation leads to a high increase in the level of TF binding. These changes in DNA-binding specificity after UV irradiation, at both consensus and non-consensus sites, have important implications for the regulatory and mutagenic roles of TFs in the cell.