Life Stage and Tissue-Specific Expression of the Homeobox Gene cnox1-Pc of the Hydrozoan Podocoryne carnea

Aerne, Birgit L.; Baader, Christine D.; Schmid, Volker

doi:10.1006/dbio.1995.1168

Cited by 51 publications

(46 citation statements)

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“…vicinity of anterior (PG-1͞2, Gsx) and posterior (PG-9͞10, cdx) Hox͞paraHox sequences from bilaterian species. The cnox-1 sequences isolated from anthozoan (17,31) and hydrozoan (15,18,22,23) species appeared as a monophyletic family in both NJ and ML trees (Figs. 2 and 3).…”

Section: High Conservation Of Non-hox Antp-class Gene Families In Metmentioning

confidence: 99%

“…Within the last years, a large number of diploblastic Antp-related genes have been isolated (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31). Among those, cnidarian sequences related to Hox and paraHox genes were found (15, 17-19, 22, 23, 25, 28, 29, 31), but the characterization of diploblastic Hox families, as well as their possible relatedness to triploblastic families, remains unclear in several cases (26,32).…”

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confidence: 99%

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Evolution of Antp-class genes and differential expression ofHydra Hox/paraHoxgenes in anterior patterning

Gauchat

Mazet

Berney

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

176

125

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The conservation of developmental functions exerted by Antpclass homeoproteins in protostomes and deuterostomes suggested that homologs with related functions are present in diploblastic animals. Our phylogenetic analyses showed that Antp-class homeodomains belong either to non-Hox or to Hox͞paraHox families. Among the 13 non-Hox families, 9 have diploblastic homologs, Msx, Emx, Barx, Evx, Tlx, NK-2, and Prh͞Hex, Not, and Dlx, reported here. Among the Hox͞paraHox, poriferan sequences were not found, and the cnidarian sequences formed at least five distinct cnox families. Two are significantly related to the paraHox Gsx (cnox-2) and the mox (cnox-5) sequences, whereas three display some relatedness to the Hox paralog groups 1 (cnox-1), 9͞10 (cnox-3) and the paraHox cdx (cnox-4). Intermediate Hox͞paraHox genes (PG 3 to 8 and lox) did not have clear cnidarian counterparts. In Hydra, cnox-1, cnox-2, and cnox-3 were not found chromosomally linked within a 150-kb range and displayed specific expression patterns in the adult head. During regeneration, cnox-1 was expressed as an early gene whatever the polarity, whereas cnox-2 was up-regulated later during head but not foot regeneration. Finally, cnox-3 expression was reestablished in the adult head once it was fully formed. These results suggest that the Hydra genes related to anterior Hox͞paraHox genes are involved at different stages of apical differentiation. However, the positional information defining the oral͞aboral axis in Hydra cannot be correlated strictly to that characterizing the anterior-posterior axis in vertebrates or arthropods. T he discovery of structural and functional homologies between regulatory genes used by Drosophila and vertebrates during their development led to the hypothesis that animals would share a common set of genes for defining the head, trunk, and posterior regions at early developmental stages (1-6). The proposed genes were homeobox genes belonging either to the Antp class, like empty-spiracle (emx), even-skipped (evx), Hox genes, or to the Prd class, like orthodenticle (Otx), goosecoid. Phylogenetic analyses performed on a vast amount of Hox homeodomain (HD) sequences, including representatives from all classes of homeobox genes from animals, protozoa, fungi, and plants, confirmed the monophyly of the Antp class as well as its position as a sister group to the Paired class (7). Within the Antp class, the Hox gene organization is distinctive and enigmatic: the genes map in clusters, and the order of individual genes within a cluster correlates with their temporospatial expression pattern along the anterior-posterior body axis during development (8). Recently, it was proposed that the common bilaterian ancestor of protostomes and deuterostomes had at least seven Hox genes (9). However, the question of the composition of the ancestral HOX cluster remains open. Analysis of Hox homeobox sequences (10) suggested that the conserved HOX cluster emerged early in the evolution of metazoans from an original cluster harboring three ancestral g...

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Section: High Conservation Of Non-hox Antp-class Gene Families In Metmentioning

confidence: 99%

mentioning

confidence: 99%

Evolution of Antp-class genes and differential expression ofHydra Hox/paraHoxgenes in anterior patterning

Gauchat

Mazet

Berney

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

176

125

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“…The generality of this hypothesis was challenged by the findings of HOM/Hox genes in almost all metazoan phyla, including cnidarians (Schummer et al, 1992;Shenk et al, 1993;Aerne et al, 1995), sponges, and placozoans, so in the living representatives of the very beginning of metazoan evolution (see Le Guyader, 1994, for a review). The meaning of such a widely shared feature probably lies in the definition of the "zootype" (Slack et al, 1993;Minelli & Schräm, 1994), linked to HOM/Hox selector genes as a common molecular basis for the polarisation of metazoan development, ruling animal body architectures through regional specification.…”

Section: Modularity and Metamery Two Faces Of The Same Medal?mentioning

confidence: 99%

The cnidarian premises of metazoan evolution: From triploblasty, to coelom formation, to metamery

Boero

Gravili

Pagliara

et al. 1998

Italian Journal of Zoology

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The hydromedusan subumbrellar muscle tissues originate from a mass of endo-and ectoderm derived cells proliferating inwardly. This mass of cells, called entocodon, is separated by the ectoand endoderm through a layer of extracellular matrix, thus forming a locally triploblastic arrangement of tissues. By cavitation and differentiation, the entocodon gives rise to the striated and smooth muscle layers of the subumbrella. The structure of the striated muscle is histologically identical to that described for triploblasts, where striated muscle is mainly mesodermic. Together with the mode of development, this suggests that not all Cnidaria are diploblastic and that the subumbrellar cavity is a coelom-like structure. The subumbreHar cavity is formed late in ontogeny, whereas the coelom in higher animals is normally formed during embryonic development. Instead of remaining closed, the subumbrella becomes open, with the muscular mesothelium in contact with the environment. This view of cnidarian structures can be pushed further while considering the regulation of modularity and metamery. The occurrence of homeotic genes in cnidarians and other 'lower' animals shows that the specification of body architecture has a common molecular ground throughout the animal kingdom. It is suggested that the expression of homeotic genes while specifying a given architecture might be regulated by iteration of their activity, leading to 'low' modular organisms and to 'higher' metameric ones. Replicated parts as modules and metameres might be analogous, but the affinity in their molecular specification (and possibly regulation) might indicate homology. The number of resemblances between cnidarians and 'higher' metazoa suggests that this phylum might be a centre of metazoan radiation, having structures which represent the living premises of the main steps of animal evolution.

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“…The recent molecular analysis of a variety of developmental regulatory genes (Aerne et al, 1995;Spring et al, 2000Spring et al, , 2002Mü ller et al, 2003) indicate that the budding process can be viewed as a continuation of gastrulation, where larva formation concludes the first and bud formation the second phase. Schematic drawings of medusa development are included in Figures 5 and 6.…”

Section: Expression In the Developing And Adult Medusamentioning

confidence: 99%

“…Medusa buds were staged according to Frey (1968). Eggs and larval stages were obtained as described (Aerne et al, 1995).…”

Section: Experimental Procedures Animalsmentioning

confidence: 99%

Basic leucine zipper transcription factors C/EBP and MafL in the hydrozoan jellyfish Podocoryne carnea

Seipel¹,

Yanze²,

Müller³

et al. 2004

Developmental Dynamics

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Life Stage and Tissue-Specific Expression of the Homeobox Gene cnox1-Pc of the Hydrozoan Podocoryne carnea

Cited by 51 publications

References 0 publications

Evolution of Antp-class genes and differential expression ofHydra Hox/paraHoxgenes in anterior patterning

Evolution of Antp-class genes and differential expression ofHydra Hox/paraHoxgenes in anterior patterning

The cnidarian premises of metazoan evolution: From triploblasty, to coelom formation, to metamery

Basic leucine zipper transcription factors C/EBP and MafL in the hydrozoan jellyfish Podocoryne carnea

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