Identification of a Hydra homologue of the β-catenin/plakoglobin/armadillo gene family

Hobmayer, Engelbert; Hatta, Masayuki; Fischer, Reinhard; Fujisawa, Toshitaka; Holstein, Thomas W.; Sugiyama, T.

doi:10.1016/0378-1119(96)00162-x

Cited by 48 publications

(26 citation statements)

References 25 publications

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“…Initial work identified the canonical Wnt/b-catenin pathway in Hydra with a wnt3a, dishevelled, gsk-3b, bcatenin and tcf/lef (Hobmayer et al, 1996;Hobmayer et al, 2000) as well as a putative Wnt receptor frz7 (Minobe et al, 2000). Recent work revealed that almost all bilaterian wnt gene subfamilies are present in cnidarians (Kusserow et al, 2005;Lee et al, 2006 unpublished work from the HR Bode, B Hobmayer and TW Holstein labs) suggesting that the main genes of the Wnt pathways are present in cnidarians.…”

Section: Members Of Cnidarian Wnt Signallingmentioning

confidence: 99%

“…These include orthologs of b-catenin (Hobmayer et al, 1996), GSK-3b, Tcf/Lef, Dsh, APC and Axin from the Wnt/ b-catenin pathway , Flamingo, Van Gogh, and JNK from the Wnt/PCP (planar cell polarity) pathway; and CamKII and PKC from the Wnt/Ca 2 þ pathway (Lee et al, 2006), but also for casein kinase 1a, 1d, 1g 2 , 1g 3 and 1e (T Lengfeld and TW Holstein, unpublished), which are all known to act in Wnt signalling (Price, 2006;Strutt et al, 2006). Furthermore, the evidences indicating Nematostella and Hydra have several kinds of receptors for canonical and non-canonical Wnts have now started to accumulate.…”

Section: Receptors and Intracellular Components Of Wnt Signallingmentioning

confidence: 99%

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The Wnt code: cnidarians signal the way

et al. 2006

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Cnidarians are the simplest metazoans with a nervous system. They are well known for their regeneration capacity, which is based on the restoration of a signalling centre (organizer). Recent work has identified the canonical Wnt pathway in the freshwater polyp Hydra, where it acts in organizer formation and regeneration. Wnt signalling is also essential for cnidarian embryogenesis. In the sea anemone Nematostella vectensis 11 of the 12 known wnt gene subfamilies were identified. Different wnt genes exhibit serial and overlapping expression domains along the oral-aboral axis of the embryo (the 'wnt code'). This is reminiscent of the hox code (cluster) in bilaterian embryogenesis that is, however, absent in cnidarians. It is proposed that the common ancestor of cnidarians and bilaterians invented a set of wnt genes that patterned the ancient main body axis. Major antagonists of Wnt ligands (e.g. Dkk 1/2/4) that were previously known only from chordates, are also present in cnidarians and exhibit a similar conserved function. The unexpectedly high level of genetic complexity of wnt genes evolved in early multi-cellular animals about 650 Myr ago and suggests a radical expansion of the genetic repertoire, concurrent with the evolution of multi-cellularity and the diversification of eumetazoan body plans. Oncogene (2006Oncogene ( ) 25, 7450-7460. doi:10.1038 Keywords: Wnt signalling; regeneration; axis formation; Hydra; Nematostella; cnidaria Cnidarians are genetically complexThe Cnidaria is an ancient metazoan phylum of diploblastic animals including freshwater polyps and hydroids, sea anemones and corals, and jellyfish. All cnidarians share the same simple body plan that is reminiscent of an early bilaterian gastrula. However, they are lacking the mesoderm and possess only two germ layers, an outer ectoderm and inner endoderm that are separated by an acellular mesogloea. Cnidaria are a sister-group to the Bilateria (Figure 1), and the fossil record reveals that cnidarians are >500 Myr old (Chen et al., 2000(Chen et al., , 2002Conway Morris, 2000). They are of crucial importance for unravelling the origin and evolution of major signalling pathways in animal evolution.There are two major genetic model systems for cnidarians: the well-known freshwater polyp Hydra (Steele, 2006) and the starlet sea anemone Nematostella vectensis (Holland, 2004;Darling et al., 2005), which was introduced by the pioneering work of Cadet Hand (Hand and Uhlinger, 1992). Recent EST projects in these and some other cnidarian taxa have revealed an astonishing and unexpected genetic complexity of cnidarians. Analyses of ESTs from the anthozoans Acropora millepora and Nematostella vectensis have lead to the identification of 16 571 non-redundant ESTs and 12 547 predicted peptides across the two species (7484 from Nematostella and 5063 from Acropora (Miller et al., 2005;Technau et al., 2005). Both data sets are far from saturation and one can estimate that anthozoan genomes are likely to contain 25 000 genes, which is in the same range as vertebr...

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Section: Members Of Cnidarian Wnt Signallingmentioning

confidence: 99%

Section: Receptors and Intracellular Components Of Wnt Signallingmentioning

confidence: 99%

The Wnt code: cnidarians signal the way

et al. 2006

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“…The principle players, the Cadherins, are an ancient family of adhesion molecules, possibly even represented in the social amoeba of Dictyostelium (Wong et al, 1996; see also Grimson et al, 2000), and in the primitive metazoan Hydra (Hobmayer et al, 1996). The extent and diversity of this family has only recently been fully appreciated with the completion of the C. elegans, Drosophila, and human genomes, (Hynes and Zhao, 2000;Nollet et al, 2000;Hill et al, 2001).…”

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confidence: 99%

Turn‐off, drop‐out: Functional state switching of cadherins

Lilien

Balsamo

Arregui

et al. 2002

Developmental Dynamics

149

116

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The classic cadherins are a group of calcium dependent, homophilic cell-cell adhesion molecules that drive morphogenetic rearrangements and maintain the integrity of cell groups through the formation of adherens junctions. The formation and maintenance of cadherin-mediated adhesions is a multistep process and mechanisms have evolved to regulate each step. This suggests that functional state switching plays an important role in development. Among the many challenges ahead is to determine the developmental role that functional state switching plays in tissue morphogenesis and to define the roles of each of the several regulatory interactions that participate in switching. One correlate of the loss of cadherinmediated adhesion, the "turn-off" of cadherin function, is the exit, or "drop-out" of cells from neural and epithelial layers and their conversion to a motile phenotype. We suggest that epithelial mesenchymal conversions may be initiated by signaling pathways that result in the loss of cadherin function. Tyrosine phosphorylation of ␤-catenin is one such mechanism. Enhanced phosphorylation of tyrosine residues on ␤-catenin is almost invariably associated with loss of the cadherin-actin connection concomitant with loss of adhesive function. There are several tyrosine kinases and phosphatases that have been shown to have the potential to alter the phosphorylation state of ␤-catenin and thus the function of cadherins. Our laboratory has focused on the role of the nonreceptor tyrosine phosphatase PTP1B in regulating the phosphorylation of ␤-catenin on tyrosine residues. Our data suggest that PTP1B is crucial for maintenance of N-cadherin-mediated adhesions in embryonic neural retina cells. By using an L-cell model system constitutively expressing N-cadherin, we have worked out many of the molecular interactions essential for this regulatory interaction. Extracellular cues that bias this critical regulatory interaction toward increased phosphorylation of ␤-catenin may be a critical component of many developmental events.

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“…The "nding (Hobmayer et al, 1996;Holstein, 1999) that the gradient-based Wnt signalling pathway, including its close coupling to the cadherin/catenin adhesion/transcription regulating system is already fully present and active in the development of Cnidaria, i.e. very primitive metazoans, make it even more interesting to study systems in which gradients, cell adhesion and cell di!erentiation are closely coupled.…”

Section: Discussionmentioning

confidence: 99%

Evolving Mechanisms of Morphogenesis: on the Interplay between Differential Adhesion and Cell Differentiation

Hogeweg

2000

Journal of Theoretical Biology

163

130

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Di!erential cell adhesion, mediated by e.g. integrin and cadherins/catenines, plays an important role in morphogenesis and it has been shown that there is intimate cross-talk between their expression and modi"cation, and inter-cellular signalling, cell di!erentiation, cell growth and apoptosis. In this paper, we introduce and use a formal model to explore the morphogenetic potential of the interplay between these processes. We demonstrate the formation of interesting morphologies. Initiated by cell di!erentiation, di!erential cell adhesion leads to a long transient of cell migrations, e.g. engul"ng and intercalation of cells and cell layers. This transient can be sustained dynamically by further cell di!erentiation, and by cell growth/division and cell death which are triggered by the (also long range) forces (stretching and squeezing) generated by the cell adhesion. We study the interrelation between modes of cell di!erentiation and modes of morphogenesis. We use an evolutionary process to zoom in on gene-regulation networks which lead to cell di!erentiation. Morphogenesis is not selected for but appears as a side-e!ect. The evolutionary dynamics shows the hallmarks of evolution on a rugged landscape, including long neutral paths. We show that a combinatorially large set of morphologies occurs in the vicinity of a neutral path which sustains cell di!erentiation. Thus, an almost linear molecular phylogeny gives rise to mosaic evolution on the morphological level. Academic Press

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Identification of a Hydra homologue of the β-catenin/plakoglobin/armadillo gene family

Cited by 48 publications

References 25 publications

The Wnt code: cnidarians signal the way

The Wnt code: cnidarians signal the way

Turn‐off, drop‐out: Functional state switching of cadherins

Evolving Mechanisms of Morphogenesis: on the Interplay between Differential Adhesion and Cell Differentiation

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