A temporo-spatial programmed ependymal denudation leads to hydrocephalus in the hyh mutant mouse

*Address correspondence to: A.J. Jiménez. Departamento de Biología Celular y Genética, Facultad de Ciencias, Universidad de Málaga, Spain. e-mail: [email protected] ABSTRACT Hyh is a lethal autosomal recessive mouse mutation located in chromosome 7. Newborn homozygous mutants presented moderate hydrocephalus, and then a severe hydrocephalus develops during the first postnatal days (PérezFígares et al., 1998). Mutant embryos showed a well-defined pattern of ependymal cell denudation in floor and in basal plate derivatives and later in alar plate derivatives. A relationship between ependymal denudation and degree of ependymal differentiation can be observed. Ependymal denudation precedes hydrocephalus; an increased bulk flow of brain fluid may be causing the hydrocephalus developed in these embryos. The floor plate of hindbrain detached whereas that of the spinal cord did not, further supporting the functional zonation of the floor plate.