1. From the 3D Lab (Development, Differentiation, and Degeneration), Department of Cellular and Molecular Physiopathology, Centro de Investigaciones Biolo´gicas, Consejo Superior de Investigaciones Cienti´ficas, Madrid, Spain; the
2. Department of Physiology, Universidad de Alcala´, Alcala´ de Henares, Spain; and
3. Department of Biochemistry and Molecular Biology, Center of Animal Biotechnology and Gene Therapy, Universitat Auto`noma de Barcelona, Bellaterra, Spain.