Fig. 1.

Schematic views of the different CRISPR/dCas9 genome-labeling systems. In the SunTag system, nuclease-deficient CRISPR/Cas9 (dCas9) protein is fused with a 24X repeating GCN4 peptide array, which could recruit multiple copies of scFv-GFP, thereby enabling labeling of specific genomic loci in living cells. The Casilio (20XPBSc) system consists of the dCas9 protein, a gRNA appended with 20xPUF-binding sites (gRNA-20XPBS), and fluorescent proteins fused with a PUF domain. The 2XMS2 system contains the dCas9 protein, a gRNA containing 3’ 2XMS2 hairpins that can recruit four molecules of MS2 coating protein (MCP)-GFP. 24XMBSV5 contains 24X synonymous MS2 hairpins