Project description:Sequencing was performed to assess the ability of Nanopore direct cDNA and native RNA sequencing to characterise human transcriptomes. Total RNA was extracted from either HAP1 or HEK293 cells, and the polyA+ fraction isolated using oligodT dynabeads. Libraries were prepared using Oxford Nanopore Technologies (ONT) kits according to manufacturers instructions. Samples were then sequenced on ONT R9.4 flow cells to generate fast5 raw reads in the ONT MinKNOW software. Fast5 reads were then base-called using the ONT Albacore software to generate Fastq reads.
Project description:Rapidly increased studies by third-generation sequencing [Pacific Biosciences (Pacbio) and Oxford Nanopore Technologies (ONT)] have been used in all kinds of research areas. Among them, the plant full-length single-molecule transcriptome studies were most used by Pacbio while ONT was rarely used. Therefore, in this study, we developed ONT RNA-sequencing methods in plants. We performed a detailed evaluation of reads from Pacbio and Nanopore PCR cDNA (ONT Pc) sequencing in plants (Arabidopsis), including the characteristics of raw data and identification of transcripts. We aimed to provide a valuable reference for applications of ONT in plant transcriptome analysis.
Project description:The Oxford Nanopore (ONT) platform provides portable and rapid genome sequencing, and its ability to natively profile DNA methylation without complex sample processing is attractive for clinical sequencing. We recently demonstrated ONT shallow whole-genome sequencing to detect copy number alterations (CNA) from the circulating tumor DNA (ctDNA) of cancer patients. Here, we show that cell-type and cancer-specific methylation changes can also be detected, as well as cancer-associated fragmentation signatures. This feasibility study suggests that ONT shallow WGS could be a powerful tool for liquid biopsy, especially real-time medical applications.
2022-04-27 | GSE185307 | GEO
Project description:Long Read Sequencing of HG00733
Project description:Investigation of transcriptome changes in four human cell lines (BJ, BJ-5ta, U2OS and HeLa) after treatment for 24 hours with nicotinamide adenine dinucleotide (NAD+). Cells were untreated as the control condition. Nanopore sequencing of cDNA was performed after library preparation with the ONT SQK-PCB109 kit.
Project description:The purpose was to investigate transcript and splicing changes in U2OS cells following siRNA-mediated depletion of MDC1 and PLRG1 or treatment with the splicing inhibitor pladienolide B. Cells were treated with control siRNA as control condition. Nanopore sequencing of cDNA was performed after library preparation with ONT kits SQK-PCS109 and SQK-PBK004.
Project description:Alternative splicing contributes to transcriptomic complexity and plays a role in the regulation of cellular identity and function, but the correct assembly of transcripts of complex loci as well as their quantification based on short-read sequencing is non-trivial. Recent long-read sequencing methods such as those from ONT and PacBio overcome these problems by potentially sequencing full transcripts. The activation of brown adipose tissue e.g., by reduced ambient temperature (cold) exposure, positively affects metabolism by increasing energy expenditure and releasing endocrine factors and has been shown to involve specific alternative splicing events. Here we assessed important features of ONT long read sequencing protocols in relation to Illumina short read sequencing: (i) Alignment characteristics to the reference genome and transcriptome, (ii) Gene and transcript detection and quantification, (iii) Detection of differential gene and transcript expression events, (iv) Transcriptome reannotation and (v) Detection of differential transcript usage events. We find that ONT long-read sequencing is advantageous in terms of transcriptome reassembly, especially when the reads are enriched for full length reads. Illumina sequencing, due to the higher number of counts available, has a higher statistical power for calling differentiall expressed/used features, whereas long-read sequencing has a lower risk of calling false positive events due to the better ability to unambiguously map reads to transcripts. Finally we describe novel transcript isoforms in cold-activated murine iBAT reassembled from ONT long reads.
Project description:Alternative splicing contributes to transcriptomic complexity and plays a role in the regulation of cellular identity and function, but the correct assembly of transcripts of complex loci as well as their quantification based on short-read sequencing is non-trivial. Recent long-read sequencing methods such as those from ONT and PacBio overcome these problems by potentially sequencing full transcripts. The activation of brown adipose tissue e.g., by reduced ambient temperature (cold) exposure, positively affects metabolism by increasing energy expenditure and releasing endocrine factors and has been shown to involve specific alternative splicing events. Here we assessed important features of ONT long read sequencing protocols in relation to Illumina short read sequencing: (i) Alignment characteristics to the reference genome and transcriptome, (ii) Gene and transcript detection and quantification, (iii) Detection of differential gene and transcript expression events, (iv) Transcriptome reannotation and (v) Detection of differential transcript usage events. We find that ONT long-read sequencing is advantageous in terms of transcriptome reassembly, especially when the reads are enriched for full length reads. Illumina sequencing, due to the higher number of counts available, has a higher statistical power for calling differentiall expressed/used features, whereas long-read sequencing has a lower risk of calling false positive events due to the better ability to unambiguously map reads to transcripts. Finally we describe novel transcript isoforms in cold-activated murine iBAT reassembled from ONT long reads.