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Hans R Bode

Publications and source records attributed to Hans R Bode.

7 recordsLinked to original sources
PubMed2006

PI3K and ERK 1-2 regulate early stages during head regeneration in hydra.

Different signaling systems coordinate and regulate the development of a multicellular organism. In hydra, the canonical Wnt pathway and the signal transduction pathways mediated by PKC and Src regulate early stages of head formation. In this paper, we present evidence for the participation of a third pathway, the PI3K-PKB pathway, involved in this process. The data presented here are consistent with the participation of ERK 1-2 as a point of convergence for the transduction pathways mediated by PKC, Src and PI3K for the regulation of the regeneration of the head in hydra. The specific developmental point regulated by them appears to be the commitment of tissue at the apical end of the regenerate to form the head organizer.

Animals↗
PubMed2005

Hym-301, a novel peptide, regulates the number of tentacles formed in hydra.

Hym-301 is a peptide that was discovered as part of a project aimed at isolating novel peptides from hydra. We have isolated and characterized the gene Hym-301, which encodes this peptide. In an adult, the gene is expressed in the ectoderm of the tentacle zone and hypostome, but not in the tentacles. It is also expressed in the developing head during bud formation and head regeneration. Treatment of regenerating heads with the peptide resulted in an increase in the number of tentacles formed, while treatment with Hym-301 dsRNA resulted in a reduction of tentacles formed as the head developed during bud formation or head regeneration. The expression patterns plus these manipulations indicate the gene has a role in tentacle formation. Furthermore, treatment of epithelial animals indicates the gene directly affects the epithelial cells that form the tentacles. Raising the head activation gradient, a morphogenetic gradient that controls axial patterning in hydra, throughout the body column results in extending the range of Hym-301 expression down the body column. This indicates the range of expression of the gene appears to be controlled by this gradient. Thus, Hym-301 is involved in axial patterning in hydra, and specifically in the regulation of the number of tentacles formed.

Amino Acid Sequence↗
PubMed2005

Formation of the head organizer in hydra involves the canonical Wnt pathway.

Stabilization of beta-catenin by inhibiting the activity of glycogen synthase kinase-3beta has been shown to initiate axis formation or axial patterning processes in many bilaterians. In hydra, the head organizer is located in the hypostome, the apical portion of the head. Treatment of hydra with alsterpaullone, a specific inhibitor of glycogen synthase kinase-3beta, results in the body column acquiring characteristics of the head organizer, as measured by transplantation experiments, and by the expression of genes associated with the head organizer. Hence, the role of the canonical Wnt pathway for the initiation of axis formation was established early in metazoan evolution.

Animals↗
PubMed2004

HyBMP5-8b, a BMP5-8 orthologue, acts during axial patterning and tentacle formation in hydra.

Developmental gradients play a central role in axial patterning in hydra. As part of the effort towards elucidating the molecular basis of these gradients as well as investigating the evolution of the mechanisms underlying axial patterning, genes encoding signaling molecules are under investigation. We report the isolation and characterization of HyBMP5-8b, a BMP5-8 orthologue, from hydra. Processes governing axial patterning are continuously active in adult hydra. Expression patterns of HyBMP5-8b in normal animals and during bud formation, hydra's asexual form of reproduction, were examined. These patterns, coupled with changes in patterns of expression in manipulated tissues during head regeneration, foot regeneration as well as under conditions that alter the positional value gradient indicate that the gene is active in two different processes. The gene plays a role in tentacle formation and in patterning the lower end of the body axis.

Amino Acid Sequence↗
PubMed2003

Head regeneration in Hydra.

Hydra, a primitive metazoan, has a simple structure consisting of a head, body column, and foot aligned along a single oral-aboral axis. The body column has a high capacity for regeneration of both the head and foot. Because of the tissue dynamics that take place in adult Hydra, the processes governing axial patterning are continuously active to maintain the form of the animal. Regeneration in hydra is morphallactic and closely related to these axial patterning processes. As might be expected, analysis at the molecular level indicates that the same set of genes are involved in head regeneration and the maintenance of the head in the context of the tissue dynamics of the adult. The genes analyzed so far play roles in axial patterning processes in bilaterians.

Animals↗
PubMed2002

Characterization of the head organizer in hydra.

A central process in the maintenance of axial patterning in the adult hydra is the head activation gradient, i.e. the potential to form a secondary axis, which is maximal in the head and is graded down the body column. Earlier evidence suggested that this gradient was based on a single parameter. Using transplantation experiments, we provide evidence that the hypostome, the apical part of the head, has the characteristics of an organizer in that it has the capacity to induce host tissue to form most of the second axis. By contrast, tissue of the body column has a self-organizing capacity, but not an inductive capacity. That the inductive capacity is confined to the hypostome is supported by experiments involving a hypostome-contact graft. The hypostome, but not the body column, transmits a signal(s) leading to the formation of a second axis. In addition, variations of the transplantation grafts and hypostome-contact grafts provide evidence for several characteristics of the organizer. The inductive capacity of the head and the self-organizing capacity of the body column are based on different pathways. Head inhibition, yya signal produced in the head and transmitted to the body column to prevent head formation, represses the effect of the inducing signal by interfering with formation of the hypostome/organizer. These results indicate that the organizer characteristics of the hypostome of an adult hydra are similar to those of the organizer region of vertebrate embryos. They also indicate that the Gierer-Meinhardt model provides a reasonable framework for the mechanisms that underlie the organizer and its activities. In addition, the results suggest that a region of an embryo or adult with the characteristics of an organizer arose early in metazoan evolution.

Animals↗