TY - JOUR
T1 - En-2 regulates the expression of the ligands for Eph type tyrosine kinases in chick embryonic tectum
AU - Shigetani, Yasuyo
AU - Funahashi, Jun Ichi
AU - Nakamura, Harukazu
N1 - Funding Information:
We are indebted to Dr S.H. Hughes for the RCAS retroviral vectors, to Drs J.G. Flanagan and M. Nakamoto for the probe of Elf-1, and to Dr A. Kawakami for the E9 chick cDNA library. We thank Dr N. Itasaki for her helpful discussion. This work was supported in part by The Naito Foundation, by Uruma Trust Fund, by Grants-in-Aid for Scientific Research from the Ministry of Education, Science, Sports and Culture, and by Special Coordination Funds for Promoting Science and Technology.
PY - 1997/3
Y1 - 1997/3
N2 - 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.
AB - 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.
KW - Chick embryo
KW - En-2
KW - Eph type receptor tyrosine kinases and ligands
KW - Retinotectal projection
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U2 - 10.1016/S0168-0102(96)01151-0
DO - 10.1016/S0168-0102(96)01151-0
M3 - Article
C2 - 9129179
AN - SCOPUS:0030937599
VL - 27
SP - 211
EP - 217
JO - Neuroscience Research
JF - Neuroscience Research
SN - 0168-0102
IS - 3
ER -