RT Journal Article
SR Electronic
T1 Nanopore dwell time analysis permits sequencing and conformational assignment of pseudouridine in SARS-CoV-2
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2021.05.10.443494
DO 10.1101/2021.05.10.443494
A1 Aaron M. Fleming
A1 Nicole J. Mathewson
A1 Cynthia J. Burrows
YR 2021
UL http://biorxiv.org/content/early/2021/05/10/2021.05.10.443494.abstract
AB Nanopore devices can directly sequence RNA, and the method has the potential to determine locations of epitranscriptomic modifications that have grown in significance because of their roles in cell regulation and stress response. Pseudouridine (Ψ), the most common modification in RNA, was sequenced with a nanopore system using a protein sensor with a helicase brake in synthetic RNAs with 100% modification at 18 known human pseudouridinylation sites. The new signals were compared to native uridine (U) control strands to characterize base calling and associated errors as well as ion current and dwell time changes. The data point to strong sequence context effects in which Ψ can easily be detected in some contexts while in others Ψ yields signals similar to U that would be false negatives in an unknown sample. We identified that the passage of Ψ through the helicase brake slowed the translocation kinetics compared to U and showed a smaller sequence bias that could permit detection of this modification in RNA. The unique signals from Ψ relative to U are proposed to reflect the syn-anti conformational flexibility of Ψ not found in U, and the difference in π stacking between these bases. This observation permitted analysis of SARS-CoV-2 nanopore sequencing data to identify five conserved Ψ sites on the 3’ end of the viral sub-genomic RNAs, and other less conserved Ψ sites. Using the helicase as a sensor protein in nanopore sequencing experiments enables detection of this modification in a greater number of relevant sequence contexts. The data are discussed concerning their analytical and biological significance.Competing Interest StatementAaron Fleming consults for a local biotechnology company Electronic BioSciences on the chemistry and biology of DNA and RNA. This could be perceived as a conflict of interest because they are developing DNA and RNA sequencing technology.