Signaling molecules in regenerating hydra

Galliot, Brigitte

doi:10.1002/bies.950190108

Cited by 23 publications

(8 citation statements)

References 82 publications

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“…In other words, the inflicted injury (amputation) is capable of activating the same genetic cascade normally used to initiate asexual reproduction. (47) Yet, there are animals adept at regenerating entire organisms from their parts in which asexual reproduction and regenerative abilities are dissociated from each other. Examples are provided by the triploblastic planarians.…”

Section: Asexual Reproduction and Regenerationmentioning

confidence: 99%

“…At the same time, these cells are continually changing their morphology as they move to these poles in order to physiologically maintain the functional/structural integrity of this organism. (54) As noted previously by Galliot, (47) this property of the gastric column, i.e., to serve as a source of pluripotential cells, is not dissimilar from that of a regeneration blastema. In hydra, the gastric column can be functionally likened to a regeneration blastema, and regeneration in this animal goes directly to the postblastemal regenerative stages observed in higher organisms, i.e., determination and differentiation (Fig.…”

Section: Cellular Pluripotentiality and Regenerationmentioning

confidence: 99%

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Regeneration in the metazoans: why does it happen?

Alvarado

2000

BioEssays

287

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Why does regeneration occur? And why, when it manifests itself, does it do so in some but not all metazoan species? Hence, what are the permissive or inhibitory factors operating behind this phenomenon? When it comes to regeneration, many questions, such as these, remain unanswered. In fact, the problem of animal regeneration has withstood the probing of scientific inquiry for over 250 years and still awaits a satisfactory mechanistic explanation. In this essay, I will review the distribution and the modes of regeneration that are found in the different metazoan phyla. Also, I will re‐examine ideas on its evolutionary origins, and discuss its possible relationship to both asexual reproduction and embryogenesis. This endeavor has two objectives. First, to bring forward an interpretation of regeneration which integrates evolutionary and developmental considerations into its discussion. And second, to suggest a comparative experimental approach to this problem that may bring us closer to understanding the molecular basis of this long‐standing biological problem. BioEssays 22:578–590, 2000. © 2000 John Wiley & Sons, Inc.

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Section: Asexual Reproduction and Regenerationmentioning

confidence: 99%

Section: Cellular Pluripotentiality and Regenerationmentioning

confidence: 99%

Regeneration in the metazoans: why does it happen?

Alvarado

2000

BioEssays

287

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“…The basal-disc-specific peroxidase activity, thought to be due to the gene expression of PPOD1 (Hoffmeister-Ullerich et al 2002), is present in all Hydra species (Hoffmeister and Schaller 1985;Galliot 1997; personal observation). To examine whether a common PPOD1-like gene is present in these species, we analyzed the PPOD gene family at the genomic level in Hydra species representing all four taxonomic groups (Fig.…”

Section: Resultsmentioning

confidence: 96%

“…As the basal-disc-specific peroxidase, most likely encoded by PPOD1, is present in all Hydra species monitored (Hoffmeister and Schaller 1985;Galliot 1997; personal observation) and since the low number of one or two signals on the Southern blots for H. circumcincta and H. viridis (Fig. 3d) corresponds to two signals in the H. oligactis blot (Fig.…”

Section: Ppod Genes As Molecular Markers For Foot Differentiationmentioning

confidence: 94%

Foot differentiation and genomic plasticity in Hydra: lessons from the PPOD gene family

Thomsen

Bosch

2006

Dev Genes Evol

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In Hydra, developmental processes are permanently active to maintain a simple body plan consisting of a two-layered, radially symmetrical tube with two differentiated structures, head and foot. Foot formation is a dynamic process and includes terminal differentiation of gastric epithelial cells into mucous secreting basal disc cells. A well-established marker for this highly specialized cell type is a locally expressed peroxidase (Hoffmeister et al. 1985). Based on the foot-specific peroxidase activity, the gene PPOD1 has been identified (Hoffmeister-Ullerich et al. 2002). Unexpectedly, this approach led to the identification of a second gene, PPOD2, with high sequence similarity to PPOD1 but a strikingly different expression pattern. Here, we characterize PPOD2 in more detail and show that both genes, PPOD1 and PPOD2, are members of a gene family with differential complexity and expression patterns in different Hydra species. At the genomic level, differences in gene number and structure within the PPOD gene family, even among closely related species, support a recently proposed phylogeny of the genus Hydra and point to unexpected genomic plasticity within closely related species of this ancient metazoan taxon.

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“…It was the first invertebrate used to study regeneration of patterns (Trembley, 1744). Today we know that pattern formation is controlled by gradients of head and foot specific small peptides; their signal transduction pathways, however, still need to be established (reviewed in Galliot, 1997;Hassel et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

Cell-substrate interactions in Cnidaria

Schmid

Ono

Reber‐Müller

1999

Microsc. Res. Tech.

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Studies on morphogenesis and regeneration in cnidarians have a long history, and the importance of cell‐ECM (extracellular matrix) interactions for these processes has been well recognized and studied since the middle of the 20th century. Cnidarians have a life cycle with a larva, a polyp, and often a medusa generation. In the medusa, the ECM (mesoglea) is very prominent and essentially shapes the animal. In the larva and the polyp, the ECM is a thin layer. Some of the ECM components known from vertebrates have been identified in cnidarians by immunohistochemistry, electron microscopy, rotary shadowing, biochemistry, and molecular cloning. In vivo and in vitro experiments suggest that the cnidarian ECM plays a role in cell migration and morphogenesis comparable to that known from other developmental systems. In the fresh water polyp Hydra, regeneration of body patterns and migration of nematocytes seems to require the presence of ECM ligands and the corresponding cell receptors. In hydrozoan medusae, DNA replication and the stability of the differentiated state of isolated tissue can be influenced by altering the properties of the ECM substrate. When cultured, most cnidarian cells survive only when attached to ECM substrates, they rarely divide and die within short times. Microsc. Res. Tech. 44:254–268, 1999. © 1999 Wiley‐Liss, Inc.

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Signaling molecules in regenerating hydra

Cited by 23 publications

References 82 publications

Regeneration in the metazoans: why does it happen?

Regeneration in the metazoans: why does it happen?

Foot differentiation and genomic plasticity in Hydra: lessons from the PPOD gene family

Cell-substrate interactions in Cnidaria

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