Publications by authors named "Auxane Buresi"

4 Publications

  • Page 1 of 1

The Pax gene family: Highlights from cephalopods.

PLoS One 2017 2;12(3):e0172719. Epub 2017 Mar 2.

UMR BOREA MNHN/CNRS7208/IRD207/UPMC/UCN/UA, Muséum National d'Histoire Naturelle, Sorbonne Universités, Paris, France.

Pax genes play important roles in Metazoan development. Their evolution has been extensively studied but Lophotrochozoa are usually omitted. We addressed the question of Pax paralog diversity in Lophotrochozoa by a thorough review of available databases. The existence of six Pax families (Pax1/9, Pax2/5/8, Pax3/7, Pax4/6, Paxβ, PoxNeuro) was confirmed and the lophotrochozoan Paxβ subfamily was further characterized. Contrary to the pattern reported in chordates, the Pax2/5/8 family is devoid of homeodomain in Lophotrochozoa. Expression patterns of the three main pax classes (pax2/5/8, pax3/7, pax4/6) during Sepia officinalis development showed that Pax roles taken as ancestral and common in metazoans are modified in S. officinalis, most likely due to either the morphological specificities of cephalopods or to their direct development. Some expected expression patterns were missing (e.g. pax6 in the developing retina), and some expressions in unexpected tissues have been found (e.g. pax2/5/8 in dermal tissue and in gills). This study underlines the diversity and functional plasticity of Pax genes and illustrates the difficulty of using probable gene homology as strict indicator of homology between biological structures.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0172719PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5333810PMC
August 2017

Emergence of sensory structures in the developing epidermis in sepia officinalis and other coleoid cephalopods.

J Comp Neurol 2014 Sep 8;522(13):3004-19. Epub 2014 Apr 8.

Museum National d'Histoire Naturelle (MNHN), DMPA, UMR Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), MNHN CNRS 7208, IRD 207, UPMC, CP51 75005, Paris, France; Université Pierre et Marie Curie-Paris, Paris, 6, France.

Embryonic cuttlefish can first respond to a variety of sensory stimuli during early development in the egg capsule. To examine the neural basis of this ability, we investigated the emergence of sensory structures within the developing epidermis. We show that the skin facing the outer environment (not the skin lining the mantle cavity, for example) is derived from embryonic domains expressing the Sepia officinalis ortholog of pax3/7, a gene involved in epidermis specification in vertebrates. On the head, they are confined to discrete brachial regions referred to as "arm pillars" that expand and cover Sof-pax3/7-negative head ectodermal tissues. As revealed by the expression of the S. officinalis ortholog of elav1, an early marker of neural differentiation, the olfactory organs first differentiate at about stage 16 within Sof-pax3/7-negative ectodermal regions before they are covered by the definitive Sof-pax3/7-positive outer epithelium. In contrast, the eight mechanosensory lateral lines running over the head surface and the numerous other putative sensory cells in the epidermis, differentiate in the Sof-pax3/7-positive tissues at stages ∼24-25, after they have extended over the entire outer surfaces of the head and arms. Locations and morphologies of the various sensory cells in the olfactory organs and skin were examined using antibodies against acetylated tubulin during the development of S. officinalis and were compared with those in hatchlings of two other cephalopod species. The early differentiation of olfactory structures and the peculiar development of the epidermis with its sensory cells provide new perspectives for comparisons of developmental processes among molluscs.
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http://dx.doi.org/10.1002/cne.23562DOI Listing
September 2014

Delayed and asynchronous ganglionic maturation during cephalopod neurogenesis as evidenced by Sof-elav1 expression in embryos of Sepia officinalis (Mollusca, Cephalopoda).

J Comp Neurol 2013 May;521(7):1482-96

Muséum National d'Histoire Naturelle (MNHN), DMPA, UMR Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), MNHN CNRS 7208, IRD 207, UPMC, 75005 Paris, France.

Among the Lophotrochozoa, centralization of the nervous system reaches an exceptional level of complexity in cephalopods, where the typical molluscan ganglia become highly developed and fuse into hierarchized lobes. It is known that ganglionic primordia initially emerge early and simultaneously during cephalopod embryogenesis but no data exist on the process of neuron differentiation in this group. We searched for members of the elav/hu family in the cuttlefish Sepia officinalis, since they are one of the first genetic markers of postmitotic neural cells. Two paralogs were identified and the expression of the most neural-specific gene, Sof-elav1, was characterized during embryogenesis. Sof-elav1 is expressed in all ganglia at one time of development, which provides the first genetic map of neurogenesis in a cephalopod. Our results unexpectedly revealed that Sof-elav1 expression is not similar and not coordinated in all the prospective ganglia. Both palliovisceral ganglia show extensive Sof-elav1 expression soon after emergence, showing that most of their cells differentiate into neurons at an early stage. On the contrary, other ganglia, and especially both cerebral ganglia that contribute to the main parts of the brain learning centers, show a late extensive Sof-elav1 expression. These delayed expressions in ganglia suggest that most ganglionic cells retain their proliferative capacities and postpone differentiation. In other molluscs, where a larval nervous system predates the development of the definitive adult nervous system, cerebral ganglia are among the first to mature. Thus, such a difference may constitute a cue in understanding the peculiar brain evolution in cephalopods.
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http://dx.doi.org/10.1002/cne.23231DOI Listing
May 2013

orthodenticle/otx ortholog expression in the anterior brain and eyes of Sepia officinalis (Mollusca, Cephalopoda).

Gene Expr Patterns 2012 Mar-Apr;12(3-4):109-16. Epub 2012 Feb 18.

Muséum National d'Histoire Naturelle (MNHN), Département Milieux et Peuplements Aquatiques (DMPA), UMR Biologie des ORganismes et Ecosystèmes Aquatiques (BOREA), MNHN CNRS 7208, IRD 207, UPMC, Paris, France; Université Paris Diderot, Sorbonne Paris Cité, Paris, France.

The origin of cerebral structures is a major issue in both developmental and evolutionary biology. Among Lophotrochozoans, cephalopods present both a derived nervous system and an original body plan, therefore they constitute a key model to study the evolution of nervous system and molecular processes that control the neural organization. We characterized a partial sequence of an ortholog of otx2 in Sepia officinalis embryos, a gene specific to the anterior nervous system and eye development. By in situ hybridization, we assessed the expression pattern of otx2 during S. officinalis organogenesis and we showed that otx is expressed (1) in the eyes, from early to late developmental stages as observed in other species (2) in the nervous system during late developmental stages. The otx ortholog does not appear to be required for the precocious emergence of the nervous ganglia in cephalopods and is later expressed only in the most anterior ganglia of the future brain. Finally, otx expression becomes restricted to localized part of the brain, where it could be involved in the functional specification of the central nervous system of S. officinalis. These results suggest a conserved involvement of otx in eye maturation and development of the anterior neural structures in S. officinalis.
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http://dx.doi.org/10.1016/j.gep.2012.02.001DOI Listing
June 2015