8 Eph Receptors and Ephrins
Are Key Regulators of Morphogenesis
N. Holder, L. Durbin, and J. Cooke
8.1
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 123
8.2
Eph/Ephrin Signalling Functions in Axon Guidance
in the Peripheral and Central Nervous System. . . . . . . . . . . . . . .. 126
8.3
Eph Signalling is Involved in Controlling Neural Crest Cell
Migration ............................................ 129
8.4
Function of Eph/Ephrin Signalling in the Formation
of Boundaries in the Somites and Hindbrain .... . . . . . . . . . . . .. 132
8.5
Principles of Eph/Ephrin Signalling. . . . . . . . . . . . . . . . . . . . . . .. 136
8.6
Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 140
References .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 141
8.1 Introduction
Morphogenesis is the creation of form during development. In all vertebrate embryos cells move and change shape in precise patterns at specific times to generate the tissues and layers of the forming body. The
molecular basis of the control of morphogenesis is not well understood.
The Eph receptors and their ligands the ephrins, represent a cellular
signalling system that is important for the correct enactment of morphogenetic processes in the vertebrate and invertebrate embryo. These proteins are known to be key players in a number of morphogenetic events
in the vertebrate embryo including axon guidance in the developing
nervous system, neural crest migration and segmentation of the paraxial
mesoderm and the hindbrain region of the neural plate. This review