En-2 regulates the expression of the ligands for Eph type tyrosine kinases in chick embryonic tectum

Yasuyo Shigetani, Jun Ichi Funahashi, Harukazu Nakamura

Research output: Contribution to journalArticlepeer-review

72 Citations (Scopus)

Abstract

The retinotectal projection map is organized in a precise retinotopic order, so that the temporo-nasal axis of the retina corresponds to the rostro-caudal axis of the tectum. en-1 and en-2, homologues of the Drosophila segment polarity gene engrailed, are expressed in a gradient along the rostro-caudal axis of the tectal anlage, and are suggested to confer caudal characteristics as the results of transplantation and ectopic engrailed (en) expression. Recently the ligands for Eph type receptor tyrosine kinases have been shown to be expressed strongly at the caudal tectum and play a role in retinotectal map formation by repulsing the temporal retinal fibers. Using the system of replication competent retroviral vector, en-2 RCAS (A/B), we misexpressed en-2 on the tectum. Elf-1 or RAGS was induced at the ectopic En-2 sites. The present results have shown that En-2 can regulate expression of both Elf-1 and RAGS. This suggests that the cells which express en at the early stage of tectum development acquire positional specificity as 'caudal' tectum, and these cells may later express the ligands for Eph type receptor tyrosine kinases. Therefore the temporal retinal fibers which have the receptors are repelled when they meet the ligands on the tectum.

Original languageEnglish
Pages (from-to)211-217
Number of pages7
JournalNeuroscience Research
Volume27
Issue number3
DOIs
Publication statusPublished - 1997 Mar

Keywords

  • Chick embryo
  • En-2
  • Eph type receptor tyrosine kinases and ligands
  • Retinotectal projection

ASJC Scopus subject areas

  • Neuroscience(all)

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