CRISPRa screening of CD28 gene region in Jurkat cells

To investigate the internal regulatory mechanisms governing the CD28 gene region during T cell activation and to screen for truly active dynamic chromatin regulatory elements responsive to stimulation, we employed the CRISPRa gene editing technology to design specific sgRNAs targeting this region and conducted a tilling CRISPRa screen sequencing on the CD28 gene region. Overall design: We performed tilling CRISPRa screening of CD28 gene region in Jurkat cells. Anti-CD28 and anti-CD3 antibodies were utilized to activate T cells as previously described (Simeonov et al. Nature, 2017). Briefly, the culture plate was coated with 10 µg/ml of anti-CD28 (TONBO Biosciences, 40-0289) for 12 hours at 4°C prior to cell inoculation. Jurkat or CD4+ T cells were then seeded with 10 µg/ml of anti-CD3 (40-0038). The cells were harvested 24 hours later for subsequent experimental analysis.