QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online January 16, 2004
doi: 10.1242/10.1242/dev.00970

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Watanabe, Y. Articles by Nakamura, H. Search for Related Content PubMed PubMed Citation Articles by Watanabe, Y. Articles by Nakamura, H.

Navigation of trochlear motor axons along the midbrain-hindbrain boundary by neuropilin 2

¹ Department of Molecular Neurobiology, Institute of Development, Aging and Cancer, Tohoku University, Aoba-ku, Sendai 980-8575, Japan
² Graduate School of Life Sciences, Tohoku University, Aoba-ku, Sendai 980-8575, Japan

^* Author for correspondence (e-mail: yuji{at}idac.tohoku.ac.jp)

Accepted 29 October 2003

Trochlear motor axons project dorsally along the midbrain-hindbrain boundary (MHB) to decussate at the dorsal midline. We report on the roles of neuropilin 2 and its ligands in the molecular mechanisms controlling this trajectory. In chick embryos, neuropilin 2 was expressed in the neuroepithelium of the dorsal isthmus in addition to the trochlear neurons, and Sema3F transcripts were localized along the caudal margin of the midbrain. Misexpression of Sema3F demonstrated that Sema3F displays repulsive activity in vivo that guides the trochlear motor axons along the MHB. An unexpected result was that misexpression of neuropilin 2 canceled the midbrain-evoked repulsion, allowing trochlear motor axons to cross the MHB and invade the tectum. A binding assay with neuropilin 2 ectodomain revealed the existence of neuropilin 2 ligands in the midbrain, which were masked by ectopic neuropilin 2. We therefore propose that neuropilin 2 neutralizes the repulsive activity in order to steer trochlear motor axons towards the dorsal decussation point. Taken together, our results suggest that the interaction of neuropilin 2 with its ligands has crucial roles for establishing trochlear trajectory along the MHB.

Key words: Chick, Trochlear nerve, Axon guidance, MHB, Neuropilin 2, Sema3F

This article has been cited by other articles:

				R. W. Burgess, T. J. Jucius, and S. L. Ackerman Motor Axon Guidance of the Mammalian Trochlear and Phrenic Nerves: Dependence on the Netrin Receptor Unc5c and Modifier Loci J. Neurosci., May 24, 2006; 26(21): 5756 - 5766. [Abstract] [Full Text] [PDF]