Hopp Children's Cancer Center at the NCT Heidelberg (KiTZ) 1 article published in JoVE Developmental Biology CRISPR-mediated Loss of Function Analysis in Cerebellar Granule Cells Using In Utero Electroporation-based Gene Transfer Weijun Feng*1, Lena Herbst*2, Peter Lichter2, Stefan M. Pfister3,4,5, Hai-Kun Liu1, Daisuke Kawauchi3,4 1Division of Molecular Neurogenetics, German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, 2Division of Molecular Genetics, German Cancer Research Center (DKFZ), and German Cancer Consortium (DKTK), 3 Conventional loss-of-function studies of genes using knockout animals have often been costly and time-consuming. Electroporation-based CRISPR-mediated somatic mutagenesis is a powerful tool to understand gene functions in vivo. Here, we report a method to analyze knockout phenotypes in proliferating cells of the cerebellum.