Imaging X-gal and GFP Colocalization

Confocal images to probe colocalization of X-gal precipitates and GFP fluorescent signal were acquired using a Leica TCS SP2 microscope, as described (Levitsky et al., 2013 (link)). This technique, based on X-gal fluorescence emission and mathematical optical correction, allows to directly image X-gal staining on thick tissue sections by confocal microscopy. As there is not need to use specific antibodies against ß-gal, this technique has lower detection threshold, high specificity and reliability. Its use has been previously validated for the detection of GDNF-positive cells (Hidalgo-Figueroa et al., 2012 (link)). Using this technique, we systematically analyzed colocalization of X-gal perinuclear precipitates with anti-EGFP inmunofluorescent signal in at least three mice.