Inhibition of stenotele differentiation by head tissue in Hydra

1987 ◽  
Vol 87 (2) ◽  
pp. 315-322
Author(s):  
TOSHITAKA FUJISAWA
Keyword(s):  
Epithelial Cells ◽  
Interstitial Cell ◽  
Position Effect ◽  
Cell Lineage ◽  
The Body ◽  
Regional Pattern ◽  
Inhibitory Signal ◽  
Body Column ◽  
Head Regeneration

Stenotele nematocytes in Hydra are differentiated predominantly in the proximal regions and in gradually decreasing numbers in the more distal regions of the body column. To test whether this position effect is directed by an inhibitory signal from head tissue or by a stimulatory signal from foot tissue, head or foot tissue was laterally grafted from one animal to different positions on another animal. Heads grafted to proximal positions strongly inhibited stenotele differentiation, while the foot exhibited no stimulatory effect. In addition, tissue from gastric regions showed intermediate levels of inhibition. Thus, the inhibitory signal appears to be distributed in a gradient along the body column from head to foot. During head regeneration, the inhibitory signal disappeared abruptly from the distal tip and reappeared rapidly. These results suggest that the inhibitory signal is involved in generating the regional pattern of stenotele differentiation. Head tissue from epithelial hydra, which lacks the interstitial cell lineage, also inhibited stenotele differentiation, suggesting that the inhibitory signal is localized in epithelial cells.

Genetic analysis of developmental mechanisms in hydra. V. Cell lineage and development of chimera hydra

1978 ◽  
Vol 32 (1) ◽  
pp. 215-232
Author(s):  
T. Sugiyama ◽  
T. Fujisawa
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Interstitial Cell ◽  
Cell Lineage ◽  
Interstitial Cells ◽  
Nerve Cells ◽  
Polyp Size ◽  
Primary Determinant ◽  
One Year ◽  
Almost All

Chimeric hydra were produced by making use of a strain (nf-1) which lacks interstitial cells, nerve cells and nematocytes. This strain arises by spontaneous loss of interstitial cells from its parental strain (sf-1) (Sugiyama & Fujisawa, 1978). Reintroduction of interstitial cells from other strains into nf-1 leads to the creation of chimeric strains that consisted of epithelial cells derived from strain sf-1 and interstitial cells and their derivatives (nerves and nematocytes) from other strains. In chimeras, interstitial or epithelial cells apparently maintain very stable cell lineages; no indication was obtained that suggested interstitial cell differentiation into epithelial cells or dedifferentiation in the opposite direction during the long courses of chimera cultures (up to one year). Developmental characters of chimeras were examined and compared to those of the epithelial cell (sf-1) and the interstitial cell donors. Almost all of the chimera's characters examined (growth rate, budding rate, tentacle numbers, polyp size, regenerative capacity, etc.) closely resembled those of the epithelial cell donor, but not of the interstitial cell donors. This suggests that epithelial cells, rather than interstitial or nerve cells, are the primary determinant of most, if not all, of hydra developmental characters.

Regulation of interstitial cell differentiation in Hydra attenuata. VI. Positional pattern of nerve cell commitment is independent of local nerve cell density

1981 ◽  
Vol 52 (1) ◽  
pp. 85-98
Author(s):  
S. Heimfeld ◽  
H.R. Bode
Keyword(s):  
Cell Density ◽  
Nerve Cell ◽  
Interstitial Cell ◽  
Cell Types ◽  
Nerve Cells ◽  
The Body ◽  
Hydra Attenuata ◽  
Cell Densities ◽  
Cell Commitment ◽  
Body Column

The interstitial cell of hydra is a multipotent stem cell, which produces nerve cells as one of its differentiated cell types. The amount of interstitial cell commitment to nerve differentiation varies in an axially dependent pattern along the body column. The distribution of nerve cell density has the same equivalent axial pattern. These facts have led to speculation that the regulation of nerve cell commitment is dictated by the nerve cell density. We examined this question by assaying interstitial cell commitment behaviour in 2 cases where the normal nerve cell density of the tissue had been perturbed: (1) in epithelial hydra in which no nerve cells were present; and (2) in hydra derived from regenerating-tip isolates in which the nerve density was increased nearly 4-fold. We found no evidence of regulation of nerve cell commitment in response to the abnormal nerve cell densities. However, the typical axial pattern of nerve commitment was still obtained in both sets of experiments, which suggests that interstitial cell commitment to nerve differentiation is dependent on some parameter of axial location that is not associated directly with the local nerve cell density.

scholarly journals The Hippo pathway transcriptional co-activator YAP is involved in head regeneration and bud development in Hydra

2021 ◽  
Author(s):  
Manu Krishnan Unni ◽  
Puli Chandramouli Reddy ◽  
Sanjeev Galande
Keyword(s):  
Target Genes ◽  
Hippo Pathway ◽  
Early Response ◽  
Immunofluorescence Assay ◽  
The Body ◽  
Hippo Signaling ◽  
Fate Specification ◽  
The Hippo Pathway ◽  
Body Column ◽  
Head Regeneration

The Hippo signaling pathway has been shown to be involved in the regulation of cellular identity, cell/tissue size maintenance and mechanotransduction. The Hippo pathway consists of a kinase cascade which determines the nucleo-cytoplasmic localization of YAP in the cell. YAP is the effector protein in the Hippo pathway which acts as a transcriptional cofactor for TEAD. Phosphorylation of YAP upon activation of the Hippo pathway prevents it from entering the nucleus and hence abrogates its function in transcription of target genes. In Cnidaria, the information on the regulatory roles of the Hippo pathway is virtually lacking. Here, we report for the first time the existence of a complete set of Hippo pathway core components in Hydra. By studying their phylogeny and domain organization, we report evolutionary conservation of the components of the Hippo pathway. Protein modelling suggested conservation of YAP-TEAD interaction in Hydra. We also characterized the expression pattern of the homologs of yap, hippo, mob and sav in Hydra using whole mount RNA in situ hybridization and report their possible role in stem cell maintenance. Immunofluorescence assay revealed that Hvul_YAP expressing cells occur in clusters in the body column and are excluded in the terminally differentiated regions. The YAP expressing cells are recruited early during head regeneration and budding implicating the Hippo pathway in early response to injury or establishment of oral fate. These cells exhibit a non-clustered existence at the site of regeneration and budding, indicating the involvement of a new population of YAP expressing cells during oral fate specification. Collectively, we posit that the Hippo pathway is an important signaling system in Hydra, its components are ubiquitously expressed in the Hydra body column, and may play crucial role in Hydra oral fate specification.

Epithelial morphogenesis in hydra requires de novo expression of extracellular matrix components and matrix metalloproteinases

Development ◽  
2002 ◽  
Vol 129 (6) ◽  
pp. 1521-1532 ◽  
Author(s):  
Hiroshi Shimizu ◽  
Xiaoming Zhang ◽  
Jinsong Zhang ◽  
Alexey Leontovich ◽  
Kaiyin Fei ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Basement Membrane ◽  
De Novo ◽  
The Body ◽  
Developmental Model ◽  
Epithelial Morphogenesis ◽  
Fibrillar Collagen ◽  
Matrix Components ◽  
Body Column ◽  
Head Regeneration

As a member of the phylum Cnidaria, the body wall of hydra is organized as an epithelium bilayer (ectoderm and endoderm) with an intervening extracellular matrix (ECM). Previous studies have established the general molecular structure of hydra ECM and indicate that it is organized as two subepithelial zones that contain basement membrane components such as laminin and a central fibrous zone that contains interstitial matrix components such as a unique type I fibrillar collagen. Because of its simple structure and high regenerative capacity, hydra has been used as a developmental model to study cell-ECM interaction during epithelial morphogenesis. The current study extends previous studies by focusing on the relationship of ECM biogenesis to epithelial morphogenesis in hydra, as monitored during head regeneration or after simple incision of the epithelium. Histological studies indicated that decapitation or incision of the body column resulted in an immediate retraction of the ECM at the wound site followed by a re-fusion of the bilayer within 1 hour. After changes in the morphology of epithelial cells at the regenerating pole, initiation of de novo biogenesis of an ECM began within hours while full reformation of the mature matrix required approximately 2 days. These processes were monitored using probes to three matrix or matrix-associated components: basement membrane-associated hydra laminin β1 chain (HLM-β1), interstitial matrix-associated hydra fibrillar collagen (Hcol-I) and hydra matrix metalloproteinase (HMMP). While upregulation of mRNA for both HLM-β1 and Hcol-I occurred by 3 hours, expression of the former was restricted to the endoderm and expression of the latter was restricted to the ectoderm. Upregulation of HMMP mRNA was also associated with the endoderm and its expression paralleled that for HLM-β1. As monitored by immunofluorescence, HLM-β1 protein first appeared in each of the two subepithelial zones (basal lamina) at about 7 hours, while Hcol-I protein was first observed in the central fibrous zone (interstitial matrix) between 15 and 24 hours. The same temporal and spatial expression pattern for these matrix and matrix-associated components was observed during incision of the body column, thus indicating that these processes are a common feature of the epithelium in hydra. The correlation of loss of the ECM, cell shape changes and subsequent de novo biogenesis of matrix and matrix-associated components were all functionally coupled by antisense experiments in which translation of HLM-β1 and HMMP was blocked and head regeneration was reversibly inhibited. In addition, inhibition of translation of HLM-β1 caused an inhibition in the appearance of Hcol-I into the ECM, thus suggesting that binding of HLM-β1 to the basal plasma membrane of ectodermal cells signaled the subsequent discharge of Hcol-I from this cell layer into the newly forming matrix. Given the early divergence of hydra, these studies point to the fundamental importance of cell-ECM interactions during epithelial morphogenesis.

Bud induction in decapitated Hydra attenuata by 5-azacytidine: a morphological study

Development ◽  
1986 ◽  
Vol 93 (1) ◽  
pp. 105-119
Author(s):  
L. De Petrocellis ◽  
V. Maharajan ◽  
B. De Petrocellis ◽  
R. Minei
Keyword(s):  
Untreated Control ◽  
Morphological Study ◽  
The Body ◽  
Gene Products ◽  
Specific Expression ◽  
Bud Formation ◽  
Bud Induction ◽  
Hydra Attenuata ◽  
Body Column ◽  
Head Regeneration

The effect of 5-azacytidine (5-azaCR) on head regeneration and budding in hydra are reported. Hydra attenuata were exposed to various doses of 5-azaCR for 48 h and then decapitated and cultured. Head regeneration and bud formation were observed for 12 days after decapitation. Untreated control hydra regenerated heads within 7 to 8 days of decapitation with a budding index of 0·2. Buds invariably arose in the normal budding zone (below the gastric region). In the group treated with 0·8mM-5-azaCR, 9 days after decapitation head regeneration was seen in only 13% of animals, and an average of two buds per hydra were formed, most of which were in the vicinity of the distal end. Induction of budding was also seen in the animals that regenerated heads. In animals exposed to 1 mM-5-azaCR three main types of responses were observed 9 days after decapitation. (1) 44% of the animals regenerated normal heads; about half of them developed at least one bud and these buds originated in the budding zone. (2) 17·5% of the animals developed abnormal, long hypostome-like structures with single or bifurcated tentacles at theirtips. There were at least two buds per animal and they were invariably at abnormal sites. (3) 32% of the animals failed to regenerate heads, although they developed two buds. 87% ofthese buds originated in abnormal sites of the body column and a large number (72%) did not detach even by the 12th day after decapitation. Both 5 and 10 mM of 5-azaCR were toxic to the animals; the survivors formed large globeshaped heads. Bud induction was seen in 60% and 28% of animals in the 5 and 10 mM groups, respectively. These observations demonstrate that 5-azaCR induces bud formation in hydra at doses that inhibit head regeneration. This bud induction might be due to a specific expression of gene products responsible for bud formation.

Expression of Cnox-2, a HOM/HOX homeobox gene in hydra, is correlated with axial pattern formation

Development ◽  
1993 ◽  
Vol 117 (2) ◽  
pp. 657-667 ◽  
Author(s):  
M.A. Shenk ◽  
H.R. Bode ◽  
R.E. Steele
Keyword(s):  
Pattern Formation ◽  
Epithelial Cells ◽  
Homeobox Gene ◽  
Specific Pattern ◽  
The Body ◽  
Body Axis ◽  
Hydra Vulgaris ◽  
Coordinate Reduction ◽  
High Level ◽  
Body Column

Cnox-2 is a HOM/HOX homeobox gene that we have identified in the simple metazoan Hydra vulgaris (Cnidaria: Hydrozoa). Cnox-2 is most closely related to anterior members of the Antennapedia gene complex from Drosophila, with the greatest similarity to Deformed. The Cnox-2 protein is expressed in the epithelial cells of adult hydra polyps in a region-specific pattern along the body axis, at a low level in the head and at a high level in the body column and the foot. The expression pattern of Cnox-2 is consistent with a role in axial pattern formation. Alteration of hydra axial patterning by treatment with diacylglycerol (DAG) results in an increase of head activation down the body column and in a coordinate reduction of Cnox-2 expression in epithelial cells in ‘head-like’ regions. These results suggest that Cnox-2 expression is negatively regulated by a signaling pathway acting through protein kinase C (PKC), and that the varying levels of expression of Cnox-2 along the body axis have the potential to result in differential gene expression which is important for hydra pattern formation.

scholarly journals Hydra tropomyosin TROP1 is expressed in head-specific epithelial cells and is a major component of the cytoskeletal structure that anchors nematocytes

1994 ◽  
Vol 107 (6) ◽  
pp. 1403-1411 ◽  
Author(s):  
M.S. Lopez de Haro ◽  
L.M. Salgado ◽  
C.N. David ◽  
T.C. Bosch
Keyword(s):  
Epithelial Cells ◽  
Single Copy ◽  
The Body ◽  
High Rate ◽  
Gastric Tissue ◽  
Single Copy Gene ◽  
Cytoskeletal Structure ◽  
Copy Gene ◽  
Form Part ◽  
Body Column

A cDNA clone encoding a 253 amino acid tropomyosin was isolated from Hydra in a differential screen for head-specific genes. The Hydra tropomyosin gene, designated trop1, is a single copy gene, lacks introns and is strongly expressed in tentacle-specific epithelial cells. Analysis of protein synthesis in head and gastric tissue indicated a high rate of tropomyosin synthesis in head tissue. Immunolocalization of tropomyosin in tentacle tissue revealed a cushion-like tropomyosin-containing structure within battery cells at the base of nematocytes. The structure appears to form part of the cytoskeletal anchor for nematocytes. Tropomyosin cushions were also observed in epithelial cells along the body column, which contain mounted stenotele nematocytes.

scholarly journals Acid Dentin Lysates Increase Amelotin Expression in Oral Epithelial Cells and Gingival Fibroblasts

2021 ◽  
Vol 11 (12) ◽  
pp. 5394
Author(s):  
Jila Nasirzade ◽  
Zahra Kargarpour ◽  
Layla Panahipour ◽  
Reinhard Gruber
Keyword(s):  
Epithelial Cells ◽  
Oral Cavity ◽  
Calcium Binding ◽  
Transforming Growth Factor ◽  
Cell Lineage ◽  
Bone Morphogenetic Protein 2 ◽  
Tooth Surface ◽  
Enamel Matrix Derivative ◽  
Gingival Fibroblasts ◽  
Smad 3

Amelotin (AMTN) is a secretory calcium-binding phosphoprotein controlling the adhesion of epithelial cells to the tooth surface, forming a protective seal against the oral cavity. It can be proposed that signals released upon dentinolysis increase AMTN expression in periodontal cells, thereby helping to preserve the protective seal. Support for this assumption comes from our RNA sequencing approach showing that gingival fibroblasts exposed to acid dentin lysates (ADL) greatly increased AMTN expression. In the present study, we confirm that acid dentin lysates significantly increase AMTN in gingival fibroblasts and extend this observation towards the epithelial cell lineage by use of the HSC2 oral squamous and TR146 buccal carcinoma cell lines. AMTN immunostaining revealed an intensive signal in the nucleus of HSC2 cells exposed to acid dentin lysates. Acid dentin lysates mediate their effect via the transforming growth factor (TGF)-β type 1 receptor kinase as the antagonist SB431542 abolished the expression of AMTN in the epithelial cells and fibroblasts. Similar to what is known for fibroblasts, acid dentin lysate increased Smad-3 phosphorylation in HSC2 cells. HSC2 cells also respond to the AMTN-stimulating activity of the dentin lysate when adsorbed to gelatin. When simulating regenerative approaches, enamel matrix derivative, TGF-β1, and bone morphogenetic protein-2 also caused a robust increase in SB431542-dependent AMTN expression in HSC2. Taken together, we show here that acid dentin lysate uses the TGF-β-depended signaling pathway to support the AMTN expression in epithelial cells, possibly helping in maintaining the protective seal against the oral cavity.

scholarly journals CHANGES IN FINE STRUCTURE DURING SILK PROTEIN PRODUCTION IN THE AMPULLATE GLAND OF THE SPIDER ARANEUS SERICATUS

1969 ◽  
Vol 42 (1) ◽  
pp. 284-295 ◽  
Author(s):  
Allen L. Bell ◽  
David B. Peakall
Keyword(s):  
Fine Structure ◽  
Epithelial Cells ◽  
Protein Production ◽  
Distal Portion ◽  
Silk Gland ◽  
The Body ◽  
Single Type ◽  
Secretory Cells ◽  
The Web ◽  
Tunica Intima

The ampullate silk gland of the spider, Araneus sericatus, produces the silk fiber for the scaffolding of the web. The fine structure of the various parts of the gland is described. The distal portion of the duct consist of a tube of epithelial cells which appear to secrete a substance which forms the tunica intima of the duct wall. At the proximal end of the duct there is a region of secretory cells. The epithelium of the sac portion contains five morphologically distinct types of granules. The bulk of the synthesis of silk occurs in the tail of the gland, and in this region only a single type of secretory droplet is seen in the epithelium. Protein synthesis can be stimulated by the injection of 1 mg/kg acetylcholine into the body fluids. 10 min after injection, much of the protein stored in the cytoplasm of the epithelial cells has been secreted into the lumen. 20 min after stimulation, the ergastoplasmic sacs form large whorls in the cytoplasm. Protein, similar in electron-opacity to protein found in the lumen, begins to form in that portion of the cytoplasm which is enclosed by the whorls. The limiting membrane of these droplets is formed by ergastoplasmic membranes which lose their ribosomes. No Golgi material has been found in these cells. Protein appears to be manufactured in the cytoplasm of the tail cells in a form which is ready for secretion.

Three digestive movements in Hydra regulated by the diffuse nerve net in the body column

2004 ◽  
Vol 190 (8) ◽  
Author(s):  
Hiroshi Shimizu ◽  
Osamu Koizumi ◽  
Toshitaka Fujisawa
Keyword(s):  
The Body ◽  
Nerve Net ◽  
Body Column
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