title: Planar cell polarity: one or two pathways?
abstract: In multicellular organisms, cells are polarized in the plane of the epithelial sheet, revealed in some cell types by oriented hairs or cilia. Many of the underlying genes have been identified in Drosophila melanogaster and are conserved in vertebrates. Here we dissect the logic of planar cell polarity (PCP). We review studies of genetic mosaics in adult flies - marked cells of different genotypes help us to understand how polarizing information is generated and how it passes from one cell to another. We argue that the prevailing opinion that planar polarity depends on a single genetic pathway is wrong and conclude that there are (at least) two independently acting processes. This conclusion has major consequences for the PCP field.
authors.affiliation: Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK. pal@mrc-lmb.cam.ac.uk
authors.forename: Peter A
authors.initials: PA
authors.lastname: Lawrence
authors.forename: Gary
authors.initials: G
authors.lastname: Struhl
authors.forename: José
authors.initials: J
authors.lastname: Casal
mesh_terms: D000818:Animals; D016764:Cell Polarity / Q000235:genetics*; D002923:Cilia / Q000235:genetics; D002999:Clone Cells; D004331:Drosophila melanogaster / Q000235:genetics*; D051379:Mice; D008954:Models, Biological; D009024:Morphogenesis; D015398:Signal Transduction