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

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 Google Scholar Google Scholar Articles by Matsunaga, E. Articles by Nakamura, H. Search for Related Content PubMed PubMed Citation Articles by Matsunaga, E. Articles by Nakamura, H.

Role of Lmx1b and Wnt1 in mesencephalon and metencephalon development

Eiji Matsunaga^*, Tatsuya Katahira and Harukazu Nakamura

Department of Molecular Neurobiology, Institute of Development, Aging & Cancer, and Graduate School of Life Sciences, Tohoku University, Seiryo-machi 4-1, Aoba-ku, Sendai 980-8575, Japan
^* Present address: INSERM U106, Bâtiment de Pédiatrie, Hôpital de la Salpêtrière, 47 Boulevard de l'Hôpital, 75013 Paris, France

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

Accepted 12 August 2002

The isthmus is the organizing center for the tectum and cerebellum. Fgf8 and Wnt1 are secreted molecules expressed around the isthmus. The function of Fgf8 has been well analyzed, and now accepted as the most important organizing signal. Involvement of Wnt1 in the isthmic organizing activity was suggested by analysis of Wnt1 knockout mice. But its role in isthmic organizing activity is still obscure. Recently, it has been shown that Lmx1b is expressed in the isthmic region and that it may occupy higher hierarchical position in the gene expression cascade in the isthmus. We have carried out misexpression experiment of Lmx1b and Wnt1, and considered their role in the isthmic organizing activity. Lmx1b or Wnt1 misexpression caused expansion of the tectum and cerebellum. Fgf8 was repressed in a cells that misexpress Lmx1b, but Fgf8 expression was induced around Lmx1b-misexpressing cells. As Lmx1b induced Wnt1 and Wnt1 induced Fgf8 expression in turn, Wnt1 may be involved in non cell-autonomous induction of Fgf8 expression by Lmx1b. Wnt1 could not induce Lmx1b expression so that Lmx1b may be put at the higher hierarchical position than Wnt1 in gene expression cascade in the isthmus. We have examined the relationship among isthmus related genes, and discuss the mechanism of the formation and maintenance of isthmic organizing activity.

Key words: Lmx1b, Wnt1, Fgf8, Isthmus, Chick