Project description:Cockayne syndrome (CS) is mainly caused by mutations in CSB gene encoding a protein belonging to SWI/SNF chromatin remodeling family. CS1AN cells derived from CS patients carrying mutations in CSB gene are useful for the study of nucleotide excision repair (NER) upon UV- or oxidative stress-induced DNA damage. However, establishment of isogenic cells endogenously expressing wild type CSB is tedious and difficult. Normal fibroblast MRC5 has been widely used to study cellular reponse to stress. This study was designed to systematically analyze the features of these two cell lines during DNA damage and repair pathways, aiming to provide a reference for application of these two cell lines as in vitro model. We show that CS1AN is hypersensitive to UV irradiation compared to MRC5. We found that CSB is essential for regulating gene expression in response to DNA damage.
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: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: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:SUMOylation is a posttranslational protein modification which is characterized by the covalent attachment of a small 11kDa protein, called Small Ubiquitin-like MOdifier (SUMO). SUMOylation plays a pivotal role in a multitude of cellular pathways including cellular responses upon DNA damage. Here, we identified multiple proteins which are SUMOylated in U2OS cells in response to ultraviolet light (UV) irradiation and ionizing radiation (IR). We show that the SUMOylation response upon UV irradiation was more pronounced compared to the response upon IR. The major SUMOylation target upon UV-irradiation was the transcription-coupled nucleotide excision repair (TC-NER) protein, Cockayne Syndrome B (CSB). This protein plays an important role in the repair of UV-induced lesions in actively transcribed genes. In a second proteomic approach we identified SUMOylation-dependent and independent protein interactors of the N-terminus of CSB. Here, we uncovered that the affinity of multiple RNA polymerase-associated proteins towards CSB is influenced by SUMOylation. Finally, we set out to identify ubiquitination events upon UV-irradiation which are influenced by the CSA-ubiquitin ligase complex, which is also involved in TC-NER and is closely connected to CSB, because mutations in either CSA or CSB result in the same phenotype, Cockayne syndrome. We found that RPB1, the major subunit of RNA polymerase II, was ubiquitinated in a CSA-dependent manner upon UV which finally led to its degradation.
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. Three biological replicates were labeled in direct and dye-swap microarray experiments and hybridized onto an Agilent custom splicing-sensitive microarray platform
Project description:human hepatoma Hep3B 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 Hep3B_UV_40J-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 Hep3B_UV_40J-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 Hep3B_UV_40J-N-MC cells impairs the recruitment of EWS-FLI1 to target genes and increases sensitivity to DNA damage. Notably, sensitivity of Hep3B_UV_40J-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 Hep3B_UV_40J-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:human hepatoma Hep3B cells were treated with 40 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 Hep3B_UV_40J-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 Hep3B_UV_40J-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 Hep3B_UV_40J-N-MC cells impairs the recruitment of EWS-FLI1 to target genes and increases sensitivity to DNA damage. Notably, sensitivity of Hep3B_UV_40J-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 Hep3B_UV_40J-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:human hepatoma Hep3B cells were treated with 40 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 Hep3B_UV_40J-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 Hep3B_UV_40J-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 Hep3B_UV_40J-N-MC cells impairs the recruitment of EWS-FLI1 to target genes and increases sensitivity to DNA damage. Notably, sensitivity of Hep3B_UV_40J-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 Hep3B_UV_40J-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. Three biological replicates were labeled in direct and dye-swap microarray experiments and hybridized onto an Agilent custom splicing-sensitive microarray platform