St. Jude Children’s Research Hospital 1 article published in JoVE Developmental Biology Fixation of Embryonic Mouse Tissue for Cytoneme Analysis Eric T. Hall1, Christina A. Daly1,2, Yan Zhang1, Miriam E. Dillard1, Stacey K. Ogden1 1Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, 2St. Jude Graduate School of Biomedical Sciences Here, an optimized step-by-step protocol is provided for fixation, immunostaining, and sectioning of embryos to detect specialized signaling filopodia called cytonemes in developing mouse tissues.