Fig. 1: Light-inducible gene activation and knock-down modules.

a, The top shows the light-inducible transcription activation module (SCPTS), based on a dCas9 fused to transcription activation domains, driving CasRx transcription in this case. A U6 promoter-driven CasRx guide RNA can be co-expressed. The middle shows PA-TetON system. The bottom shows PA-Cre–Lox. b, Synthetic promoters for light-inducible transcription of CasRx or any other cassette of interest (CaSP1/2), containing upstream elements for reducing spurious transcription (poly(A) site, pause site), a minimal CMV promoter containing TFIIB binding site/TATA box, an initiator and synthetic 5′ untranslated region (UTR), one or three sgRNA binding sites. The CasRx cassette (below) contains a T2A-GFP tag, two nuclear localization signals (NLS) and an HA tag, as in ref. ⁸. Catalytic domains (HEPN) are indicated. c, Experimental setup: HEK293T cells are transfected in a 96-well plate, which is placed on a LED board for photostimulation and cells are then imaged for GFP/NeonGreen (NG). d, For the SCPTS system, background-subtracted mean GFP intensity at indicated time points (dark or lit), with one of the three promoters (CaSP1/2, Gal4/UAS), either a nontargeting (NT) or the CaSP–CasRx-targeting guide (CasRx). Horizontal bars show the mean of all replicates per condition; dots show individual replicates. P values (Benjamini–Hochberg corrected two-sided t-test) between dark and lit conditions at 50 h are reported. e, Same as d, for the PA-TetOn and PA-Cre–Lox systems, with or without doxycycline (n = 4). P value (Benjamini–Hochberg corrected two-sided t-test) between dark and lit conditions at 24 h are reported. f,g, Representative images for the SCPTS (GFP) (f), PA-Cre–Lox (NG) and PA-TetON (GFP) (g). Scale bars, 50 μm. Images were taken at 36 h posttransfection using a Keyence BZ-X710 with ×10 magnification, in n = 6 independent experiments from those in d,e. Brightfield in Extended Data Fig. 1k.

Source data