Project description:We report that retention of intron 2 which affects expression of CD19 in CART-19 relapsed leukemia occurs in the context of full length CD19 transcript using Oxford Nanopore sequencing technology. By performing Direct RNA sequencing on Reh leukemia cell lines, we showed that intron 2 retention is functionally equivalent to nonsense mutations.
Project description:Analysis of high-throughput transcriptome sequencing (RNA-seq) data often observed numerous 'non-co-linear' (NCL) transcripts, which may originate from genetic rearrangements (gene fusion) indicated the importance of fusion events and circRNAs in carcinogenesis; however, the role of ts-RNAs remains largely uninvestigated. Here we developed a hybrid sequencing pipeline ("NCLscan-hybrid"), which integrated different types of short (Illumina-based) and extra-long (PacBio-based) RNA-seq data to eliminate potential false positives from experimental artifacts, fusion events, and circRNAs. We applied NCLscan-hybrid to investigate of ts-RNAs in human breast cancer, the most malignant tumors diagnosed in women worldwide. Through multiple experimental validation steps, we confirmed that the intragenic ts-RNA, ts-ARFGEF1, was highly expressed in breast cancer cells but absent in normal breast cells. Furthermore, we experimentally validated that ts-ARGEF1 can contribute to cell proliferation and apoptosis. Analysis of xenograft in nude mice showed that disruption of ts-ARFGEF1 expression can significantly attenuate tumor growth. Microarray analysis revealed that ts-ARFGEF1 knockdown could trigger PERK/ATF4/CHOP signaling pathway, implying the function of ts-ARFGEF1 in ER homeostasis. Taken together, our findings provide an in-depth view of the true complexity of intragenic NCL events and, for the first time, show further insight into the potential roles of intragenic ts-RNAs in tumor cell development.
Project description:Results indicate that CRISPR/Cas9 gene editing of a suboptimal E19/I19 5′ splice site in the TOP2α gene results in circumvention of acquired drug resistance to etoposide and other TOP2-targeted drugs in a clonal K562 cell line by enhancing removal of intron 19 thereby decreasing formation of a truncated TOP2α/90 isoform and increasing expression of full-length TOP2α/170 in these resistant cells.
Project description:Analysis and understanding of transcript functions is greatly helped by knowing the full-length sequence of individual RNAs. New long-read sequencing devices such as Oxford Nanopore and Pacbio have the potential to sequence full-length transcripts, but standard methods lack the ability to capture true RNA 5’ ends and selects for poly-adenylated (pA+) transcripts. We present a method that, by utilizing cap-trapping and 3’ end adapter ligation, can sequence transcripts from the exact 5’ end to 3’ end regardless of whether they are poly-adenylated, with no need for ribosomal RNA depletion. We show that the method can faithfully detect 5’ ends, splice junctions and 3’ ends, has high reproducibility between runs and gene expression estimates from the method correlate well with short-read sequencing methods. We also demonstrate that the method can detect and sequence full-length pA- RNAs, including lncRNAs, promoter upstream transcripts (PROMPTs) and enhancer RNAs. TLDR-seq is therefore useful for the characterization of diverse capped RNA species.
Project description:Analysis and understanding of transcript functions is greatly helped by knowing the full-length sequence of individual RNAs. New long-read sequencing devices such as Oxford Nanopore and Pacbio have the potential to sequence full-length transcripts, but standard methods lack the ability to capture true RNA 5’ ends and selects for poly-adenylated (pA+) transcripts. We present a method that, by utilizing cap-trapping and 3’ end adapter ligation, can sequence transcripts from the exact 5’ end to 3’ end regardless of whether they are poly-adenylated, with no need for ribosomal RNA depletion. We show that the method can faithfully detect 5’ ends, splice junctions and 3’ ends, has high reproducibility between runs and gene expression estimates from the method correlate well with short-read sequencing methods. We also demonstrate that the method can detect and sequence full-length pA- RNAs, including lncRNAs, promoter upstream transcripts (PROMPTs) and enhancer RNAs. TLDR-seq is therefore useful for the characterization of diverse capped RNA species.