Direct long-read RNA sequencing identifies a subset of questionable exitrons likely arising from reverse transcription artifacts

Genome Biol. 2021 Jun 28;22(1):190. doi: 10.1186/s13059-021-02411-1.

Abstract

Resistance to CD19-directed immunotherapies in lymphoblastic leukemia has been attributed, among other factors, to several aberrant CD19 pre-mRNA splicing events, including recently reported excision of a cryptic intron embedded within CD19 exon 2. While "exitrons" are known to exist in hundreds of human transcripts, we discovered, using reporter assays and direct long-read RNA sequencing (dRNA-seq), that the CD19 exitron is an artifact of reverse transcription. Extending our analysis to publicly available datasets, we identified dozens of questionable exitrons, dubbed "falsitrons," that appear only in cDNA-seq, but never in dRNA-seq. Our results highlight the importance of dRNA-seq for transcript isoform validation.

Keywords: Alternative splicing; Blinatumomab; CD19; Exitrons; Immunotherapy; Long-read sequencing; Oxford Nanopore Technologies; Reverse transcription; mRNA isoforms.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Alternative Splicing*
  • Antibodies, Bispecific / pharmacology
  • Antineoplastic Agents, Immunological / pharmacology
  • Artifacts*
  • B-Lymphocytes / drug effects
  • B-Lymphocytes / immunology
  • B-Lymphocytes / pathology
  • Base Pairing
  • Base Sequence
  • Cell Line, Tumor
  • Datasets as Topic
  • Exons
  • High-Throughput Nucleotide Sequencing
  • Humans
  • Immunotherapy / methods
  • Introns
  • Models, Biological
  • Nucleic Acid Conformation
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / drug therapy
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / genetics
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / immunology
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / pathology
  • Protein Isoforms / chemistry
  • Protein Isoforms / genetics
  • Protein Isoforms / immunology
  • RNA, Messenger / chemistry
  • RNA, Messenger / genetics*
  • RNA, Messenger / immunology
  • Receptors, Antigen, T-Cell / genetics*
  • Receptors, Antigen, T-Cell / immunology
  • Reverse Transcription*

Substances

  • Antibodies, Bispecific
  • Antineoplastic Agents, Immunological
  • CD19-specific chimeric antigen receptor
  • Protein Isoforms
  • RNA, Messenger
  • Receptors, Antigen, T-Cell
  • blinatumomab