Ephrin-A5 promotes the formation of terminal... : NeuroReport (original) (raw)
DEVELOPMENTAL NEUROSCIENCE
Ephrin-A5 promotes the formation of terminal thalamocortical arbors
aUniversity of Jena, Institute for General Zoology, Erberstrasse 1, Jena, Germany
bDepartment of Anatomy, Biomedical Sciences Institute, Federal University of Rio de Janeiro, Rio de Janeiro J, Brazil
Correspondence to Professor Dr Jürgen Bolz, Universität Jena, Institut für Allgemeine Zoologie und Tierphysiologie, Erberstrasse 1, 07743 Jena, Germany
Tel: +49 364 194 9101; fax: +49 364 194 9102; e-mail: [email protected]
Received 28 January 2008; accepted 21 February 2008
Abstract
Ephrins-A5 are expressed in the cortical target layer of thalamic afferents at the time when these axons form terminal arbors. Previous in-vitro studies provided evidence that ephrin-A5 supports the branching of thalamic axons, but there is no direct in-vivo evidence for such a growth-promoting effect. Here we examined thalamocortical projections in ephrins-A5 deficient mice. Our results demonstrate that the laminar specificity of thalamic afferents in ephrin-A5−/− mutants remains preserved, but axonal arbor formation is greatly reduced. Thus, ephrin-A5 specifically regulates branch formation of thalamic axons, but does not affect target layer selection. Ephrin-A5-mutant mice are, therefore, a unique model to study the effects of reduced thalamic innervation on the assembly of cortical circuits and sensory processing.
© 2008 Lippincott Williams & Wilkins, Inc.