title: Shh and Pax6 have unconventional expression patterns in embryonic morphogenesis in Sepia officinalis (Cephalopoda).
abstract: Cephalopods show a very complex nervous system, particularly derived when compared to other molluscs. In vertebrates, the setting up of the nervous system depends on genes such as Shh and Pax6. In this paper we assess Shh and Pax6 expression patterns during Sepia officinalis development by whole-mount in situ hybridization. In vertebrates, Shh has been shown to indirectly inhibit Pax6. This seems to be the case in cephalopods as the expression patterns of these genes do not overlap during S. officinalis development. Pax6 is expressed in the optic region and brain and Shh in gut structures, as already seen in vertebrates and Drosophila. Thus, both genes show expression in analogous structures in vertebrates. Surprisingly, they also exhibit unconventional expressions such as in gills for Pax6 and ganglia borders for Shh. They are also expressed in many cephalopods' derived characters among molluscs as in arm suckers for Pax6 and beak producing tissues, nuchal organ and neural cord of the arms for Shh. This new data supports the fact that molecular control patterns have evolved with the appearance of morphological novelties in cephalopods as shown in this new model, S. officinalis.
authors.affiliation: Muséum National d'Histoire Naturelle, Département Milieux et Peuplements Aquatiques, Laboratoire Biologie des ORganismes et Ecosystèmes Aquatiques, UMR MNHN USM 401, CNRS 7208, IRD 207, UPMC, Paris, France. navet@mnhn.fr
authors.forename: Sandra
authors.initials: S
authors.lastname: Navet
authors.forename: Aude
authors.initials: A
authors.lastname: Andouche
authors.forename: Sébastien
authors.initials: S
authors.lastname: Baratte
authors.forename: Laure
authors.initials: L
authors.lastname: Bonnaud
mesh_terms: D000818:Animals; D049830:Cephalopoda / Q000196:embryology; D004625:Embryo, Nonmammalian / Q000378:metabolism*; D047108:Embryonic Development; D005136:Eye Proteins / Q000235:genetics* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D053823:Hedgehog Proteins / Q000235:genetics* / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism; D009024:Morphogenesis; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors / Q000235:genetics* / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D049833:Sepia / Q000196:embryology* / Q000235:genetics / Q000378:metabolism
chemical_list: D005136:Eye Proteins; D053823:Hedgehog Proteins; D018398:Homeodomain Proteins; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D012097:Repressor Proteins