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

First published online 2 June 2004
doi: 10.1242/dev.01190

This Article Figures Only Full Text Full Text (PDF) All Versions of this Article: dev.01190v1 131/13/3121    most recent 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 Lecaudey, V. Articles by Schneider-Maunoury, S. Search for Related Content PubMed PubMed Citation Articles by Lecaudey, V. Articles by Schneider-Maunoury, S.

The zebrafish Iroquois gene iro7 positions the r4/r5 boundary and controls neurogenesis in the rostral hindbrain

¹ Unité de Biologie Moléculaire du Développement, Unité INSERM 368, Ecole Normale Supérieure, 46, rue d’Ulm, 75005 Paris, France
² Unité de Biologie du Développement, UMR CNRS 7622, Université Pierre et Marie Curie, 9 quai Saint Bernard, 75005 Paris, France

^* Author for correspondence (e-mail: maunoury{at}wotan.ens.fr)

Accepted 24 March 2004

Early brain regionalisation involves the activation of genes coding for transcription factors in distinct domains of the neural plate. The limits of these domains often prefigure morphological boundaries. In the hindbrain, anteroposterior patterning depends on a segmentation process that leads to the formation of seven bulges called rhombomeres (r). The molecular cues involved in the early subdivision of the hindbrain and in rhombomere formation are not well understood. We show that iro7, a zebrafish gene coding for a transcription factor of the Iroquois family, is expressed at the end of gastrulation in the future midbrain and hindbrain territories up to the prospective r4/r5 boundary. This territory is strictly complementary to the expression domain of another homeobox gene, vhnf1, in the caudal neural plate. We demonstrate that Iro7 represses vhnf1 expression anterior to their common border and that, conversely, vHnf1 represses iro7 expression caudal to it. This suggests that the r4/r5 boundary is positioned by mutual repression between these two transcription factors. In addition, iro7 is involved in the specification of primary neurons in the rostral hindbrain. In particular, it is essential for the formation of the Mauthner neurons in r4. We propose that iro7 has a dual function in the hindbrain of the zebrafish embryo: it is required for the proper positioning of the prospective r4/r5 boundary and it promotes neurogenesis in the anterior hindbrain.

Key words: Iroquois, iro7, vhnf1 (tcf2), Hindbrain, Boundary, Rhombomere, Neurogenesis

This article has been cited by other articles:

				S. Scholpp, I. Foucher, N. Staudt, D. Peukert, A. Lumsden, and C. Houart Otx1l, Otx2 and Irx1b establish and position the ZLI in the diencephalon Development, September 1, 2007; 134(17): 3167 - 3176. [Abstract] [Full Text] [PDF]

				R. E. Hernandez, A. P. Putzke, J. P. Myers, L. Margaretha, and C. B. Moens Cyp26 enzymes generate the retinoic acid response pattern necessary for hindbrain development Development, January 1, 2007; 134(1): 177 - 187. [Abstract] [Full Text] [PDF]

				E. Villa-Cuesta and J. Modolell Mutual repression between msh and Iro-C is an essential component of the boundary between body wall and wing in Drosophila Development, September 15, 2005; 132(18): 4087 - 4096. [Abstract] [Full Text] [PDF]

				I. O. Sirbu, L. Gresh, J. Barra, and G. Duester Shifting boundaries of retinoic acid activity control hindbrain segmental gene expression Development, June 1, 2005; 132(11): 2611 - 2622. [Abstract] [Full Text] [PDF]