TUTase mediated site-directed access to clickable chromatin employing CRISPR-dCas9

Locus-specific interrogation of the genome using programmable CRISPR-based technologies is tremendously useful in dissecting the molecular basis of target gene function and modulating its downstream output. Although these tools are widely utilized in recruiting genetically encoded functional proteins, display of small molecules using this technique is not well developed due to inadequate labeling technologies. Here, we report the development of a modular technology, sgRNA-Click (sgR-CLK), which harnesses the power of bioorthogonal click chemistry for remodeling CRISPR to display synthetic molecules on target genes. A terminal uridylyl transferase (TUTase) was repurposed to construct an sgRNA containing multiple minimally invasive bioorthogonal clickable handles, which served as a Trojan horse on CRISPR-dCas9 system to guide synthetic tags site-specifically on chromatin employing copper-catalyzed or strain-promoted click reactions. Our results demonstrate that sgR-CLK could provide a simplified solution for site-directed display of small molecules to study as well as modulate the function of gene targets.