(a) Schematic of the CsChrimson chimera. (b) Action spectra for Chrimson and CsChrimson as well as the Chrimson spectrum data from the original manuscript plotted in Figure 1e (HEK293 cells; measured using equal photon fluxes of ∼2.5 × 1021 photons/s/m2). (c) Schematic of trafficking sequences used to generate the CsChrimson Drosophila transgenics. (d,e) Maximum photocurrents in response to red (625-nm) and far-red (735-nm) light as measured in cultured neurons. (f,g) Turn-on (f) and recovery kinetics (g) in response to 735-nm light. CsChrimson kinetic data were pooled from all trafficking versions. All constructs in this panel were expressed under CaMKII promoter and selected solely on the basis of the presence of cotransfected cytosolic tdTomato expression. Illumination conditions are as labeled in each panel. Box-plot whiskers represent minimum and maximum data points. Box limits represent 25th percentile, median and 75th percentile. Chrimson-GFP: n = 9 cells in d, n = 12 cells in e; CsChrimson-GFP: n = 7 cells in d, n = 8 cells in e; CsChrimson-KGC-GFP: n = 7 cells in d,e; CsChrimson-GFP-ER2: n = 4 cells in d, n = 3 cells in e; CsChrimson-KGC-GFP-ER2: n = 10 cells in d, n = 11 cells in e. Plotted data are mean ± s.e.m. in b,f,g. ANOVA with Dunnett's post hoc test with Chrimson-GFP as reference in d,e. n.s., not significant.