Customizable host and viral transcript enrichment using CRISPR-Cas9 long-read sequencing for characterization of low-to-moderate abundance isoforms.

One of the main challenges of whole transcriptome sequencing is the difficulty in detecting and quantifying low-to-moderate abundance transcripts. Methods that address this are either complicated to scale or customize; long-range PCR is problematic to scale, and probe hybridization panels are expensive to customize. In this study, we developed an RNA-guided CRISPR-Cas9 nuclease-based enrichment strategy combined with long-read sequencing, which achieved up to 60-fold enrichment of the target. Our findings demonstrate that the CRISPR-Cas system is a highly effective method for customizable long-read sequencing of target transcripts, which preserves estimation of relative abundance.