Project description:To identify aberrant splicing isoforms and potential neoantigens, we performed full-length cDNA sequencing of lung adenocarcinoma cell lines using a long-read sequencer MinION. We constructed a comprehensive catalog of aberrant splicing isoforms and detected isoform-specific peptides using proteome analysis.
2020-12-09 | PXD019915 | JPOST Repository
Project description:full-length isoform of endosperm from Nongda3672
Project description:We developed a hybrid-sequencing workflow, combining next-generation and third-generation sequencing, to reconstruct full-length transcriptomes. Integrating with polysome profiling and ribosome footprinting data, we predicted isoform–specific translational status and reconstructed ORFeome. Moreover, we identified isoforms with specific subcellular localization pattern in neurons.
Project description:We consturcted a full-length transcript reference of CD4SP and CD8SP T cells using TGS (PacBio) data. We then used SGS (Illumina) CD4SP and CD8SP data to quantify isoform expressions and study alternative splicing patterns against the full-length transcript reference between CD4SP and CD8SP cells.
Project description:Single-cell isoform regulation is increasingly being studied. To get a full view of alternative isoform usage, from transcription start site and alternative splicing to transcription termination site, full-length sequences have to be studied. Here we use PacBio long read sequencing technology combined with unique molecular identities to get a full and accurate picture of alternative isoform usage of different stages in maturing oligodendrocyte single cells. We see that the majority of molecules in single-cells are separate isoforms, even after applying a conservative definition of what constitutes an isoform. Few isoforms are common between cells of the same cell-type but the common isoforms are higher expressed. We also see that exon junctions in coding regions are better regulated than exon junctions in non-coding regions and that genes often express more than one coding isoform.
Project description:Deregulated gene expression is a hallmark of cancer, however most studies to date have analyzed short-read RNA-sequencing data with inherent limitations. Here, we combine PacBio long-read isoform sequencing (Iso-Seq) and Illumina paired-end short read RNA sequencing to comprehensively survey the transcriptome of gastric cancer (GC), a leading cause of global cancer mortality. We performed full-length transcriptome analysis across 10 GC cell lines covering four major GC molecular subtypes (chromosomal unstable, Epstein-Barr positive, genome stable and microsatellite unstable). We identify 60,239 non-redundant full-length transcripts, of which >66% are novel compared to current transcriptome databases. Novel isoforms are more likely to be cell-line and subtype specific, expressed at lower levels with larger number of exons, with longer isoform/coding sequence lengths. Most novel isoforms utilize an alternate first exon, and compared to other alternative splicing categories are expressed at higher levels and exhibit higher variability. Collectively, we observe alternate promoter usage in 25% of detected genes, with the majority (84.2%) of known/novel promoter pairs exhibiting potential changes in their coding sequences. Mapping these alternate promoters to TCGA GC samples, we identify several cancer-associated isoforms, including novel variants of oncogenes. Tumor-specific transcript isoforms tend to alter protein coding sequences to a larger extent than other isoforms. Analysis of outcome data suggests that novel isoforms may impart additional prognostic information. Our results provide a rich resource of full-length transcriptome data for deeper studies of GC and other gastrointestinal malignancies.
Project description:A novel alternative splicing isoform of LOXL2 △e13 was expressed ubiquitously in all cell lines and ESCC tissues. In contrast to the impaired deamination enzymatic activity compared with full length LOXL2, LOXL2 △e13 showed an enhanced ability to promote cell mobility and invasiveness in ESCC cells than full length LOXL2 through a different mechanism.
Project description:Background: Transcriptional activation of structurally autonomous transposable elements (TEs) is a precursor to both autonomous and non-autonomous transposition in host genomes. However, the identification of those transcribed TE loci that are competent autonomous elements, their genomic locations and the specific conditions under which these loci can contribute to mobilisation of both autonomous and non-autonomous elements remains largely unknown. Results: A three-channel analysis pipeline was established to identified expressed TE loci. This pipeline is mainly comprised of three different existing tools (htseq-count, bedtools, and TEFingerprint) for mapped read quantification. Using Vitis vinifera embryogenic callus as a model, we exposed the callus to live cultures of an endemic grapevine yeast Hanseniaspora uvarum to determine the landscape and properties of expressed TE loci. In this system, only 1.7%-2.5% of total annotated TE loci were transcribed, of which 5%-10% of these were full-length (>90% length integrity). Collectively, these TE loci (including fragmented and structurally ‘autonomous’ loci) exhibited a significant tendency to be found within introns of expressed genes. This strong location bias towards expressed genes was also observed in Arabidopsis thaliana wild-type and ibm2, but not in ddm1. Moreover, in the grapevine model, differentially expressed TE loci tend to present similar expression pattern with co-localized differentially expressed genes. Nonetheless, utilizing Oxford Nanopore Technology (ONT) cDNA sequencing, we found a strong correlation between the inclusion of intronic TEs in gene transcripts and the presence of premature termination codons in these transcripts. Finally, we identified full-length transcripts derived from structurally autonomous TE loci in our grapevine system, although the level of these transcripts was low. Conclusions: Our observations in the two disparate plant model systems reveal the closely connected transcriptional relationship between TEs and co-localized genes when the epigenetic silencing system is not compromised. Furthermore, we found that the stress treatment alone was not sufficient to induce large scale full length transcription from structurally intact TE loci, a precursor for mobilisation of non-autonomous and autonomous elements.