Development 129, 2181-2193 (2002) 2181 Printed in Great Britain © The Company of Biologists Limited 2002 DEV2786 Cdx1 and Cdx2 have overlapping functions in anteroposterior patterning and posterior axis elongation Eric van den Akker1,*, Sylvie Forlani1,†, Kallayanee Chawengsaksophak2, Wim de Graaff1, Felix Beck2,3, Barbara I. Meyer4 and Jacqueline Deschamps1,§ 1Hubrecht Laboratory, Netherlands Institute for Developmental Biology, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands 2Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Australia 3Department of Biochemistry, University of Leicester, Leicester LE1 7RH, UK 4Department of Molecular Cell Biology, Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany *Present address: Institute of Hematology, Erasmus University, Dr Molewaterplein 50, 3015 GR, Rotterdam, The Netherlands †Present address: Unité de Biologie Moléculaire du Développement, Institut Pasteur, 25 rue du Dr Roux, 75724 Paris Cedex 15, France §Author for correspondence (e-mail:
[email protected]) Accepted 12 February 2002 SUMMARY Mouse Cdx and Hox genes presumably evolved from genes were co-operative in severity, and a more extensive on a common ancestor cluster involved in anteroposterior posterior shift of the expression of three Hox genes was patterning. Drosophila caudal (cad) is involved in specifying observed in double mutants. The alteration in Hox the posterior end of the early embryo, and is essential for expression boundaries occurred early. We conclude that patterning tissues derived from the most caudal segment, both Cdx genes cooperate at early stages in instructing the the analia. Two of the three mouse Cdx paralogues, Cdx 1 vertebral progenitors all along the axis, at least in part by and Cdx2, are expressed early in a Hox-like manner in the setting the rostral expression boundaries of Hox genes.