caa a22 4500 47576823X CHVBK 20180406123612.0 cr unu---uuuuu 170329e20000301xx s 000 0 eng 10.1007/s004270050306 doi (NATIONALLICENCE)springer-10.1007/s004270050306 Neuroectodermal and endodermal expression of the ascidian Cdx gene is separated by metamorphosis [Elektronische Daten] [V. F. Hinman, E. Becker, B. M. Degnan] Abstract : Ascidians are a group of invertebrate chordates that exhibit a biphasic life history, with chordate-specific structures developing during embryogenesis (dorsal neural tube and notochord) and metamorphosis (pharyngeal gill slits and endostyle). Here we characterize the expression of a caudal/Cdx gene homologue, Hec-Cdx, from the ascidian Herdmania curvata. Vertebrate Cdx genes are expressed at gastrulation and in the posterior of the developing neural tube and endoderm. Hec-Cdx expression is initiated at the earliest stages of gastrulation, with peaks in RNA abundance occurring first during neurulation and tailbud extension and then in 3- to 5-day-old juveniles. Hec-Cdx is expressed in a pair of cells in the anterior lip of the blastopore in the late gastrula which form the most posterior portion of the neural plate. During tailbud formation expression is maintained in and solely restricted to these cells. During metamorphosis expression is localized to the intestine of the juvenile. These data, along with data for the H. curvata Otx gene, suggest that the evolution of the novel ascidian biphasic body plan was not accompanied by a deployment of these genes into new pathways but by a temporal separation of tissue-specific expression. Springer-Verlag Berlin Heidelberg, 2000 Key words Chordate evolution nationallicence Heterochrony Urochordate nationallicence Hinman V. F. Department of Zoology and Entomology, University of Queensland, Brisbane, Queensland 4072, Australia E-mail: bdegnan@zoology.uq.edu.au Tel.: +61-7-3365-2467, Fax: +61-7-3365-1655, AU aut Becker E. Department of Zoology and Entomology, University of Queensland, Brisbane, Queensland 4072, Australia E-mail: bdegnan@zoology.uq.edu.au Tel.: +61-7-3365-2467, Fax: +61-7-3365-1655, AU aut Degnan B. M. Department of Zoology and Entomology, University of Queensland, Brisbane, Queensland 4072, Australia E-mail: bdegnan@zoology.uq.edu.au Tel.: +61-7-3365-2467, Fax: +61-7-3365-1655, AU aut https://doi.org/10.1007/s004270050306 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s004270050306 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Hinman V. F. Department of Zoology and Entomology, University of Queensland, Brisbane, Queensland 4072, Australia E-mail: bdegnan@zoology.uq.edu.au Tel.: +61-7-3365-2467, Fax: +61-7-3365-1655, AU aut NATIONALLICENCE 700 1- Becker E. Department of Zoology and Entomology, University of Queensland, Brisbane, Queensland 4072, Australia E-mail: bdegnan@zoology.uq.edu.au Tel.: +61-7-3365-2467, Fax: +61-7-3365-1655, AU aut NATIONALLICENCE 700 1- Degnan B. M. Department of Zoology and Entomology, University of Queensland, Brisbane, Queensland 4072, Australia E-mail: bdegnan@zoology.uq.edu.au Tel.: +61-7-3365-2467, Fax: +61-7-3365-1655, AU aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer