Efficient transcriptional gene activation with synthetic crRNA:tracrRNA in dCas9-VPR stable cells

HEK293T, U2OS, MCF 10A, NIH/3T3 stably expressing integrated dCas9-VPR were plated at 10,000 cells/well and transfected using DharmaFECT Transfection Reagents with synthetic crRNA:tracrRNA (25 nM) targeting POU5F1 and TTN. K562 cells were electroporated with synthetic crRNA:tracrRNA (400 nM) targeting POU5F1 and TTN. Cells were harvested 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.

Fold activation by CRISPRa varies by gene and depends on the endogenous gene expression level

Genes that have low or no basal expression are easier to activate to a robust level, and genes already being expressed are more difficult to over-express further. U2OS cells stably expressing integrated dCas9-VPR were plated at 10,000 cells/well and transfected using DharmaFECT 4 Transfection Reagent with synthetic crRNA:tracrRNA pools (25 nM) targeting genes with low to high basal transcript expression levels. Cells were harvested 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. The fold activation is shown for the genes ranked from low to high basal transcript expression level in samples treated with NTC control and is shown in the lower graph as basal gene expression relative to GAPDH expression in the same samples.

CRISPRa gene activation in U2OS cells is observed at 24 hours and peaks at 48-72 hours

CRISPRa synthetic crRNAs and pools achieve maximal activation at 48-72 hours post-transfection in dCas9-VPR-expressing cells. U2OS cells stably expressing integrated dCas9-VPR were plated at 10,000 cells/well and transfected using DharmaFECT 4 Transfection Reagent with synthetic crRNA:tracrRNA targeting EGFR, IL1R2, POU5F1 or TFAP2C. The four pre-designed crRNAs for CRISPRa 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 calculated 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.

CRISPRa crRNAs and pools are highly effective at 25 nM working concentration

A dose curve of CRISPRa crRNA:tracrRNA targeting two different genes demonstrates that a working concentration of 25 nM achieves robust target gene activation. U2OS cells stably expressing integrated dCas9-VPR were plated at 10,000 cells/well and transfected using DharmaFECT 4 Transfection Reagent with synthetic crRNA:tracrRNA targeting EGFR or POU5F1. The pre-designed crRNAs were used either individually or pooled at four concentrations (1, 5, 25, 100 nM). Cells were harvested 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.