TY - JOUR
AU - St.Onge, Robert
AB - Background: Genome-scale CRISPR interference (CRISPRi) has been used in human cell lines; however, the features of effective guide RNAs (gRNAs) in different organisms have not been well characterized. Here, we define rules that determine gRNA effectiveness for transcriptional repression in Saccharomyces cerevisiae. Results: We create an inducible single plasmid CRISPRi system for gene repression in yeast, and use it to analyze fitness effects of gRNAs under 18 small molecule treatments. Our approach correctly identifies previously described chemical-genetic interactions, as well as a new mechanism of suppressing fluconazole toxicity by repression of the ERG25 gene. Assessment of multiple target loci across treatments using gRNA libraries allows us to determine generalizable features associated with gRNA efficacy. Guides that target regions with low nucleosome occupancy and high chromatin accessibility are clearly more effective. We also find that the best region to target gRNAs is between the transcription start site (TSS) and 200 bp upstream of the TSS. Finally, unlike nuclease-proficient Cas9 in human cells, the specificity of truncated gRNAs (18 nt of complementarity to the target) is not clearly superior to full-length gRNAs (20 nt of complementarity), as truncated gRNAs are generally less potent against both mismatched and perfectly matched targets. Conclusions: 
TI - Quantitative CRISPR interference screens in yeast identify chemical-genetic interactions and new rules for guide RNA design
JF - Genome Biology
DO - 10.1186/s13059-016-0900-9
DA - 2016-03-08
UR - https://www.deepdyve.com/lp/springer-journals/quantitative-crispr-interference-screens-in-yeast-identify-chemical-C3tq5dCyJq
SP - 1
EP - 16
VL - 17
IS - 1
DP - DeepDyve
ER -