(a,b) Light-induced upregulation of ASCL1 (a) and MYOD1 (b) in HEK293T cells. Used dCas9-activators and the number of sgRNAs are indicated. (c,d) Light-induced IL1RN upregulation in HeLa cells (c) and human induced pluripotent stem cells (d) using CPTS, CPTS2.0 and Split-CPTS2.0 with a single sgRNA targeting IL1RN gene. (e) Reversible and repeatable activation of endogenous ASCL1 with CPTS2.0. Data are expressed as relative mRNA amount to the negative control transfected with empty vector in the dark and represented as mean ± s.e.m. (n=4 from two individual experiments with two cell culture replicates). D, Dark; L, Light. Welch’s two-tailed t test was performed. *p < 0.05, ** < 0.01, ***p < 0.005 versus the sample in the dark.