CRISPRa workflow diagram with stable dCas9-VPR expression

CRISPR activation workflow with lentiviral dCas9-VPR and synthetic crRNA:tracrRNA (left side) or Lentiviral expressed sgRNA (right side).

CRISPRa plasmid co-transfection workflow

CRISPRa workflow for plasmid co-transfection of lentiviral dCas9-VPR and expressed sgRNA.

CRISPRa gene activation fold depends on the endogenous gene expression level

Genes with low or no basal expression are easier to activate to a robust level, while genes already expressed at high level are more difficult to further over-express. U2OS-dCas9-VPR stable cells were plated at 10,000 cells/well and transfected using DharmaFECT 4 Transfection Reagent with CRISPRa synthetic crRNA:tracrRNA pools (25 nM) targeting 23 genes with different basal level of expression. Cells were harvested 72 hours post-transfection and the relative gene expression was measured using RT-qPCR. The CRISPRa-mediated fold transcriptional activation is shown in the upper graph where the genes are ordered from low to high level of basal transcript expression in samples treated with NTC control and is shown in the lower graph as basal target gene expression (compared to GAPDH control).

CRISPRa gene activation is observed at 24 hours and peaks at 48-72 hours

U2OS-dCas9-VPR stable cells were plated at 10,000 cells/well and transfected using DharmaFECT 4 Transfection Reagent with CRISPRa synthetic crRNA:tracrRNA targeting EGFR, IL1R2, POU5F1 or TFAP2C. Four CRISPRa crRNAs were used either individually or pooled (to a total concentration of 25 nM). Cells were harvested at 24, 48, and 72 hours post-transfection and the relative gene expression was measured using RT-qPCR. The relative expression of each gene was calculated with the Cq method using GAPDH as the housekeeping gene and normalized to a non-targeting control.