Ephrin-B2 and EphB1 Mediate Retinal Axon Divergence at the Optic Chiasm

Neuron. 2003 Sep 11;39(6):919-35. doi: 10.1016/j.neuron.2003.08.017.

Abstract

In animals with binocular vision, retinal ganglion cell (RGC) axons either cross or avoid the midline at the optic chiasm. Here, we show that ephrin-Bs in the chiasm region direct the divergence of retinal axons through the selective repulsion of a subset of RGCs that express EphB1. Ephrin-B2 is expressed at the mouse chiasm midline as the ipsilateral projection is generated and is selectively inhibitory to axons from ventrotemporal (VT) retina, where ipsilaterally projecting RGCs reside. Moreover, blocking ephrin-B2 function in vitro rescues the inhibitory effect of chiasm cells and eliminates the ipsilateral projection in the semiintact mouse visual system. A receptor for ephrin-B2, EphB1, is found exclusively in regions of retina that give rise to the ipsilateral projection. EphB1 null mice exhibit a dramatically reduced ipsilateral projection, suggesting that this receptor contributes to the formation of the ipsilateral retinal projection, most likely through its repulsive interaction with ephrin-B2.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Axons / metabolism*
  • Cells, Cultured
  • Ephrin-B1 / biosynthesis
  • Ephrin-B1 / deficiency*
  • Ephrin-B1 / genetics
  • Ephrin-B2 / biosynthesis*
  • Ephrin-B2 / genetics
  • Female
  • Gene Expression Regulation, Developmental / physiology
  • Humans
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Optic Chiasm / embryology
  • Optic Chiasm / metabolism*
  • Pregnancy
  • Retina / embryology
  • Retina / metabolism*
  • Retinal Ganglion Cells / metabolism
  • Xenopus

Substances

  • Ephrin-B1
  • Ephrin-B2