Fig. 1: Optogenetic Cre activation in the whole body of PA-Cre KI mice.
From: Photoactivatable Cre knock-in mice for spatiotemporal control of genetic engineering in vivo
a Schematics of the detection of PA-Cre-mediated recombination via fluorescence. In F1 mice expressing split PA-Cre proteins and an EGFP protein from each Rosa26 locus, blue light illumination activated PA-Cre, which removed floxed regions. Recombined cells express DsRed protein. b Preparation of the blue LED device with a heating pad and outline of the in vivo illumination experiments. Illumination for 30 min on the heating pad was repeated after 2 h, and all treated mice were kept under natural light until sacrifice. c Representative histology of PA-Cre KI and no KI in each tissue at P7. Scale bar = 200 µm. d Enlarged images in the liver and muscle at P7. Either GFP- or DsRed-expressing cells were detected in the liver section, whereas multinucleate cells in skeletal muscles expressed both GFP and DsRed protein. Scale bar = 50 µm. e Recombination efficiency in five areas of each tissue 1 week after whole-body illumination. Average data and standard deviations (error bars) were obtained from four pups. *p < 0.05; **p < 0.01. f Electrophoresis of the PCR products with primers F1 and R1, which are shown in (a). White arrowhead: wild allele; black arrowhead: recombined allele. B brain, H heart, Li liver, Sp spleen, T thymus, Sk skin, Mu muscle, K kidney, Lu lung.
