Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

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DNA-Protein Crosslink sequencing (DPC-seq) in RPE-1 cells treated with formaldehyde

ABSTRACT: Covalent DNA-protein crosslinks (DPC) are toxic DNA lesions that require repair by global-genome and replication-coupled pathways. How cells respond when RNA polymerases stall at DPCs during transcription is unknown. DPC-seq is new method for the genome-wide mapping of covalent DNA-protein adducts.

INSTRUMENT(S): Illumina HiSeq 1500, Illumina NovaSeq 6000, NextSeq 500

ORGANISM(S): Homo sapiens

SUBMITTER: Aldo Bader

PROVIDER: E-MTAB-12912 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:2×10^7 HL60 cells were treated with 10 uM ATRA for 2 and 5 days, and conducted Hi-C to study the chromosomal architecture. Cells were fixed by 1% formaldehyde (v/v) for 15 min at room temperature (RT) with slowly rotation. Cells were lysed by 550 μl lysis buffer (500 μl 10 mM Tris-HCl pH 8.0, 10 mM NaCl, 0.2% Igepal CA-630 and 50 μl protease inhibitors) using a homogenizer, and harvested the chromatin at 5,000 rpm and washed twice. The pellet was added 1% SDS and incubated at 65 oC for 10 min, then quenched by Triton X-100. The chromatin was digested by 600 U MboI (NEB, Ipswich, USA) at 37 oC overnight. The next day, enzymes were inactivated by 10% SDS at 65 oC for 30 min, and the restriction fragment overhangs were filled in using biotin-14-dCTP and Klenow at 37 oC for 45 min, and the ligation was conducted in 7.61 ml ligation mix (745 μl 10% Triton X-100, 745 μl 10x ligation buffer (500 mM Tris-HCl pH 7.5, 100 mM MgCl2, 100 mM DTT), 80 μl 10 mg/ml BSA, 80 μl 100 mM ATP and 5.96 ml water) for 4 h at 16°C. The blunt-end Hi-C ligation was sonicated and pull down by streptavidin beads, then purified by ethanol. Hi-C library was prepared for paired ending sequencing using NEBNext® UltraTM DNA Library Prep Kit for Illuina® (NEB). For regular 3C ligation, after enzymes inactivation, 10 μl 1 U/μl T4 DNA ligase was added to incubate at 16°C overnight. The interaction was detected by qPCR using the specific 3C primers (Table 1) followed by DNA purification. Hi-C was conducted in PE-150. An iterative method for Hi-C mapping with initial length 30bp, if it fails to map uniquely, the next round of mapping for additional 20 bp continued, this procedure lasts until the full read length reaches 150bp. The Hi-C reads were mapped to the human reference genome (assembly GRCh38) using bowtie2 (v2.2.9). The reads mapped to the same restriction fragment, the reads less than 500bp and PCR duplicates were all removed. Hi-C contact maps were normalized using ICE.

Project description:To address the need to study frozen clinical specimens using next-generation RNA, DNA, chromatin immunoprecipitation (ChIP) sequencing and protein analyses, we developed a biobank work flow to prospectively collect biospecimens from patients with renal cell carcinoma (RCC). We describe our standard operating procedures and work flow to annotate pathologic results and clinical outcomes. We report quality control outcomes, nucleic acid yields of our RCC submissions (N=16) to The Cancer Genome Atlas (TCGA) project, as well as newer discovery platforms by describing mass spectrometry analysis of albumin oxidation in plasma and 6 ChIP sequencing libraries generated from nephrectomy specimens after histone H3 lysine 36 trimethylation (H3K36me3) immunoprecipitation. From June 1, 2010, through January 1, 2013, we enrolled 328 patients with RCC. Our mean (SD) TCGA RNA integrity numbers (RINs) were 8.1 (0.8) for papillary RCC, with a 12.5% overall rate of sample disqualification for RIN <7. Banked plasma had significantly less albumin oxidation (by mass spectrometry analysis) than plasma kept at 25°C (P<.001). For ChIP sequencing, the FastQC score for average read quality was at least 30 for 91-95% of paired-end reads. In parallel, we analyzed frozen tissue by RNA sequencing and after genome alignments, only 0.2-0.4% of total reads failed the default quality check steps of Bowtie2, which was comparable to the disqualification ratio (0.1%) of the 786-O RCC cell line, prepared under optimal RNA isolation conditions. The overall correlation coefficients for gene expression between the Mayo Clinic vs. TCGA tissues ranged from 0.75 to 0.82. These data support the generation of high-quality nucleic acids for genomic analyses from banked RCC. Importantly, the protocol does not interfere with routine clinical care. Collections over defined time points during disease treatment further enhance collaborative efforts to integrate genomic information with outcomes. Examination of H3K36me3 in ccRCC

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DNA-Protein Crosslink sequencing (DPC-seq) in RPE-1 cells treated with formaldehyde

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