Cover legend: This whole-mount staining of the lateral walls of the lateral ventricle from an adult mouse illustrates the asymmetric positioning of basal bodies (green, γ-tubulin) on the apical surface of ependymal cells (magenta, β-catenin, which labels the junctional complexes found at the perimeter of ependymal cells). Ablation of mechanosensory genes Pkd1 or Pkd2 in the embryonic progenitors of ependymal cells affects planar cell polarity in ependymal cells and results in abnormal accumulation of cerebrospinal fluid, leading to hydrocephalus. For more information, see the article by Ohata et al. (pages 11153–11168).