Because it is notoriously difficult to purify and visualize peroxiosmes in the CNS, we generated a mouse model with GFP-labeled peroxisomes. In cooperation with Klaus-Armin Nave (Max Planck Institute for Experimental Medicine, Göttingen, Germany) we generated several transgenic mouse lines, which express a fusion protein consisting of the first 40 amino acids of the peroxisomal membrane protein Pex3, including a transmembrane domain, and EGFP. Between these two domains a peptide sequence is inserted containing an optimal recognition site for the TEV (tobacco etch virus)-protease. Expression of the transgene is driven by the human UbiC promoter, which is assumed to be ubiquitously expressed.