Screening for functional circular RNAs using the CRISPR-Cas13 system

Deep sequencing datasets are used for gRNA library analysis for large-scale screens. Using a lentiviral library that targets sequences across back-splicing sites of highly expressed human circRNAs, we show that a group of circRNAs are important for cell growth mostly in a cell-type specific manner and that a common oncogenic circRNA, circFAM120A, promotes cell proliferation in vitro and in vivo. To screen circRNAs that are important for cell proliferation, the gRNA lentiviral library-infected HT29T, 293FT and HeLa cells harvested in day 1 and day 30 were used for DNA extraction, gRNA enrichment by PCR amplification and deep sequencing.