domEx253 [mec-4p::Chrimson::GFP + unc-122p::RFP]. Pick animals with red fluorescence in coelomocytes to maintain. Red-light optogenetic line for gentle touch receptor neurons (TRN). Transgenic animals expressing the red light-activated channelrhodopsin Chrimson into TRNs using the mec-4 promoter. In animals grown on all trans-retinal-containing medium, red light stimuli trigger behaviors similar to those evoked by gentle touch. Note that very strong blue light stimuli may also activate Chrimson. Reference: Schild LC & Glauser DA. Genetics. 2015 Aug;200(4):1029-34. doi: 10.1534/genetics.115.177956. PMID: 26022242.