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:Over the last 30 years the soil bacterium Agrobacterium tumefaciens has been the workhorse tool for plant genome engineering. Replacement of native tumor-inducing (Ti) plasmid elements with customizable cassettes enabled insertion of a sequence of interest as “Transfer DNA” (T-DNA) into the plant genome of interest. Although these T-DNA transfer mechanisms are well understood, detailed understanding of the structure and epigenomic status of insertion events was limited by current technologies. To fill this gap, we analyzed transgenic Arabidopsis thaliana lines from three widely used collections (SALK, SAIL and WISC) with two single molecule technologies, optical genome mapping and nanopore sequencing. Optical maps for four randomly selected T-DNA lines revealed between one and seven insertions/rearrangements with unexpectedly large sizes ranging from 27 to 236 kilobases. De novo nanopore-based genome assemblies for two heterozygous lines resolved T-DNA structures up to 36 kb and revealed large-scale T-DNA associated translocations and exchange of chromosome arm ends. The multiple internally rearranged nature of T-DNA arrays, consisting of identical T-DNA/backbone concatemers made full assembly even for long nanopore reads impossible. For the current TAIR10 reference genome, nanopore contigs corrected 83% of non-centromeric misassemblies. This unprecedented nucleotide-level definition of T-DNA insertions enabled the mapping of epigenome data. The SALK_059379 T-DNA insertions were enriched for 24nt siRNAs and contained dense cytosine DNA methylation. Transgene silencing via the RNA directed DNA methylation pathway was confirmed by in planta assays. In contrast, SAIL_232 T-DNA sequence was predominantly targeted by 21/22nt siRNAs, and DNA methylation and silencing was limited to the GUS gene, but not the resistance gene. With the emergence of genome editing technologies that rely on Agrobacterium for gene delivery, this study provides new insights into the structural impact of engineering plant genomes and demonstrates the utility of state-of-the-art long-range sequencing technologies to rapidly identify unanticipated genomic changes. Overall design: 2 biological samples, each RNAseq, smallRNAseq and bisulfite sequencing
| GSE108401 | GEO
Project description:Sequencing runs of M13 and lambda obtained using Oxford Nanopore Technologies' MinION sequencer
Project description:The effect of an induced site-specific DNA double-strand break on DNA abundance across the chromosome of E. coli cells expressing or not RecD protein, was investigated by marker frequency analysis. Overall design: gDNA was isolated from two independent cultures ('biological repeats') of four, exponentially growing E. coli strains. Two strains experienced the induced DNA double-strand break (DL2006 and DL3391), two did not (DL2573 and DL3743). Two strains were wild-type for the recD gene (DL2006 and DL2573), two had the recD gene deleted (DL3391 and DL3743). gDNA was also isolated from two independent stationary phase cultures of strain DL2573. The libraries of the 10 gDNA preps were multiplexed and run 4 seperate times ('sequencing runs')
2018-07-18 | GSE107973 | GEO
Project description:Multiplexed nanopore sequencing of HLA-B locus in Māori and Pacific Island samples
Project description:MicroRNAs (miRNAs) are crucial for normal embryonic stem (ES) cell self-renewal and cellular differentiation, but how miRNA gene expression is controlled by the key transcriptional regulators of ES cells has not been established. We describe here a new map of the transcriptional regulatory circuitry of ES cells that incorporates both protein-coding and miRNA genes, and which is based on high-resolution ChIP-seq data, systematic identification of miRNA promoters, and quantitative sequencing of short transcripts in multiple cell types. We find that the key ES cell transcription factors are associated with promoters for most miRNAs that are preferentially expressed in ES cells and with promoters for a set of silent miRNA genes. This silent set of miRNA genes is co-occupied by Polycomb Group proteins in ES cells and expressed in a tissue-specific fashion in differentiated cells. These data reveal how key ES cell transcription factors promote the miRNA expression program that contributes to self-renewal and cellular differentiation, and integrate miRNAs and their targets into an expanded model of the regulatory circuitry controlling ES cell identity. Keywords: ChIP-seq analysis of ES cell transcriptional regulators and chromatin modifications. Cell-type comparison of short RNA transcritome. Analysis of changes in short RNA transcritome upon Oct4 ablation. ChIP-seq in murine embryonic stem cells for Oct4, Sox2 (2 runs), Nanog (2 runs), Tcf3 (2 runs), Suz12 (2 runs), H3K4me3 (4 runs), H3k79me2 (2 runs), H3k36me3 (2 runs) and whole cell extract input DNA (WCE, 2 runs). Short transcript sequencing from murine embryonic stem cells (mES, v6.5), mouse embryonic fibroblasts (MEF), murine neural precursor cells (NPC), and ZHBT-c4 cells (from Austin Smith) untreated (0h), with 12 hours of doxycyclin treatment (12h), and with 24 hours of doxycyclin treatment (24h).
Project description:The nature of chromatin as regular succession of nucleosomes has gained iconic status. However, since most nucleosomes in metazoans are poorly positioned it is unknown to which extent the bulk genomic nucleosome repeat length (NRL) reflects the regularity and spacing of nucleosome arrays at individual loci. We describe a new approach to map nucleosome fiber regularity and spacing through sequencing oligonucleosome-derived DNA by classical as well as emergent nanopore-technology. This revealed modulation of chromatin regularity and NRL depending on functional chromatin states independently of nucleosome positioning and even in unmappable regions. We also found that that nucleosome arrays downstream of silent promoters are considerably more regular than those downstream of highly expressed ones, despite most extensive nucleosome phasing of the latter. Our approach is generally applicable and provides an important parameter of chromatin organisation that so far had been missing. Overall design: Chromatin from Drosophila BG3-c2 or Kc cells was digested with MNase to oligonucleosomal ladders. Total digested DNA was either sequenced on Oxford Nanopore Minion devices, or the tetranucleosomal band was cut out and the purified DNA sequenced paired-end on an Illumina 1500 HiSeq machine to measure nucleosome repeat length along the genome with high resolution.