We propose to implement a unified platform for detecting RNA nucleotide modifications on contiguous full length RNA strands using nanopore direct RNA sequencing. In principle, this technology could be used for all classes of RNA molecules in prokaryotic and eukaryotic cells. It is a logical technical advance for RNA sequencing because the current standard, sequencing-by-synthesis using Solexa technology requires conversion of native cellular RNA into short (~300 nt) cDNA amplicons. In so doing, nucleotide modifications are erased and the continuity of intact RNA strands is lost, thus precluding accurate quantification of RNA isoforms. Nanopore strand sequencing overcomes these limitations because the ~2 nanometer-long integral sensor touches and identifies each base along intact native RNA strands as they are driven through the pore by an applied voltage. Thus, end-to-end sequence analysis of a given RNA strand is achieved. During the grant period, we will pursue three specific aims: 1) Establish baseline performance of ONT direct RNA sequencing, and implement targeted improvements; 2) Implement methods to discover and document nucleotide modifications on native RNA strands; and 3) Optimize nanopore technology for analysis of mRNA isoform diversity. UC Santa Cruz is uniquely equipped to undertake this project: i) We pioneered nanopore RNA strand analysis (Akeson/Deamer) and recently demonstrated that the Oxford Nanopore MinION nanopore sequencer can resolve single nucleotide variants and base modifications in single 16S rRNA strands (Akeson). ii) Our RNA Center includes fourteen faculty members. Co-investigators on this application have expertise in mechanisms of RNA splicing (Sanford), the functional consequences of normal and aberrant RNA isoform synthesis (Brooks), and the structural biology of RNA (Ares). Collaborating RNA Center faculty will advise on nuclear non-coding RNA experiments (Carpenter, Kim) and on H9 ES cells (Salama). iii) Our Genomics Institute is internationally recognized for bioinformatics, including recent advances in application of Recurrent Neural Networks to human genome haplotyping, and genome-wide nanopore detection of base modifications (Paten).
We will implement a unified nanopore platform for sequencing RNA nucleotide modifications on individual full length RNA strands. In principle, this platform could be used to sequence all classes of RNA molecules in human cells. This will provide unique insights into the role of RNA in neurodegenerative disorders, and in cancer.