Development 126, 4095-4106 (1999) 4095 Printed in Great Britain © The Company of Biologists Limited 1999 DEV2458 Successive patterns of clonal cell dispersion in relation to neuromeric subdivision in the mouse neuroepithelium Luc Mathis1,*, Johan Sieur1, Octavian Voiculescu2, Patrick Charnay2 and Jean-François Nicolas1,‡ 1Unité de Biologie moléculaire du Développement, Institut Pasteur, 25, rue du Docteur Roux, 75724 Paris Cedex 15, France 2Unité INSERM 368, Ecole Normale Supérieure, 46 rue d’Ulm, 75230 Paris Cedex 05, France *Present address: Beckman Institute (139-74), California Institute of Technology, Pasadena, CA, 91125, USA ‡Author for correspondence (e-mail:
[email protected]) Accepted 5 July; published on WWW 23 August 1999 SUMMARY We made use of the laacz procedure of single-cell labelling the AP and DV axis of the neural tube. A similar sequence to visualize clones labelled before neuromere formation, in of AP cell dispersion followed by an arrest of AP cell 12.5-day mouse embryos. This allowed us to deduce two dispersion, a preferential DV cell dispersion and then by a successive phases of cell dispersion in the formation of the coherent neuroepithelial growth, is also observed in the rhombencephalon: an initial anterior-posterior (AP) cell spinal cord and mesencephalon. This demonstrates that a dispersion, followed by an asymmetrical dorsoventral (DV) similar cascade of cell events occurs in these different cell distribution during which AP cell dispersion occurs in domains of the CNS. In the prosencephalon, differences in territories smaller than one rhombomere. We conclude that spatial constraints may explain the variability in the the general arrest of AP cell dispersion precedes the onset orientation of cell clusters.