title: Understanding how morphogens work.
abstract: In this article, we describe the mechanisms by which morphogens in the Xenopus embryo exert their long-range effects. Our results are consistent with the idea that signalling molecules such as activin and the nodal-related proteins traverse responding tissue not by transcytosis or by cytonemes but by movement through the extracellular space. We suggest, however, that additional experiments, involving real-time imaging of morphogens, are required for a real understanding of what influences signalling range and the shape of a morphogen gradient.
authors.affiliation: Wellcome Trust/CR-UK Gurdon Institute, Department of Zoology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK. jim@gurdon.cam.ac.uk
authors.forename: J C
authors.initials: JC
authors.lastname: Smith
authors.forename: A
authors.initials: A
authors.lastname: Hagemann
authors.forename: Y
authors.initials: Y
authors.lastname: Saka
authors.forename: P H
authors.initials: PH
authors.lastname: Williams
mesh_terms: D028341:Activins / Q000378:metabolism*; D000818:Animals; D004627:Embryonic Induction / Q000502:physiology*; D009024:Morphogenesis / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D014981:Xenopus / Q000196:embryology*
chemical_list: D028341:Activins