PT  - JOURNAL ARTICLE
AU  - Clamons, Samuel
AU  - Murray, Richard
TI  - Modeling predicts that CRISPR-based activators, unlike CRISPR-based repressors, scale well with increasing gRNA competition and dCas9 bottlenecking
AID  - 10.1101/719278
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 719278
4099  - http://biorxiv.org/content/early/2019/08/13/719278.short
4100  - http://biorxiv.org/content/early/2019/08/13/719278.full
AB  - Synthetic transcriptional networks built from CRISPR-based repressors (CRISPRi) rely on shared use of a core dCas9 protein. In E. coli, CRISPRi cannot support more than about a dozen simultaneous gRNAs before the fold repression of any individual gRNA drops below 10x. We show with a simple model based on previous characterization of competition in CRISPRi that activation by CRISPR-based activators (CRISPRa) is much less sensitive to dCas9 bottle-necking than CRISPRi. We predict that E. coli should be able to support dozens to hundreds of CRISPRa gRNAs at >10-fold activation.