1
|
Miljkovic-Licina M, Chera S, Ghila L, Galliot B. Head regeneration in wild-type hydra requires de novo neurogenesis. Development 2007; 134:1191-201. [PMID: 17301084 DOI: 10.1242/dev.02804] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Because head regeneration occurs in nerve-free hydra mutants, neurogenesis was regarded as dispensable for this process. Here, in wild-type hydra, we tested the function of the ParaHox gsx homolog gene, cnox-2,which is a specific marker for bipotent neuronal progenitors, expressed in cycling interstitial cells that give rise to apical neurons and gastric nematoblasts (i.e. sensory mechanoreceptor precursors). cnox-2 RNAi silencing leads to a dramatic downregulation of hyZic, prdl-a, gscand cnASH, whereas hyCOUP-TF is upregulated. cnox-2indeed acts as an upstream regulator of the neuronal and nematocyte differentiation pathways, as cnox-2(-) hydra display a drastic reduction in apical neurons and gastric nematoblasts, a disorganized apical nervous system and a decreased body size. During head regeneration, the locally restricted de novo neurogenesis that precedes head formation is cnox-2 dependent: cnox-2 expression is induced in neuronal precursors and differentiating neurons that appear in the regenerating tip; cnox-2 RNAi silencing reduces this de novo neurogenesis and delays head formation. Similarly, the disappearance of cnox-2+cells in sf-1 mutants also correlates with head regeneration blockade. Hence in wild-type hydra, head regeneration requires the cnox-2 neurogenic function. When neurogenesis is missing, an alternative, slower and less efficient, head developmental program is possibly activated.
Collapse
Affiliation(s)
- Marijana Miljkovic-Licina
- Department of Zoology and Animal Biology, University of Geneva, Sciences III, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | | | | | | |
Collapse
|
2
|
|
3
|
Bode HR. The interstitial cell lineage of hydra: a stem cell system that arose early in evolution. J Cell Sci 1996; 109 ( Pt 6):1155-64. [PMID: 8799806 DOI: 10.1242/jcs.109.6.1155] [Citation(s) in RCA: 140] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- H R Bode
- Department of Developmental and Cell Biology, University of California at Irvine 92717-2300, USA.
| |
Collapse
|
4
|
Zhang X, Sarras MP. Cell-extracellular matrix interactions under in vivo conditions during interstitial cell migration in Hydra vulgaris. Development 1994; 120:425-32. [PMID: 8149918 DOI: 10.1242/dev.120.2.425] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Interstitial cell (I-cell) migration in hydra is essential for establishment of the regional cell differentiation pattern in the organism. All previous in vivo studies have indicated that cell migration in hydra is a result of cell-cell interactions and chemotaxic gradients. Recently, in vitro cell adhesion studies indicated that isolated nematocytes could bind to substrata coated with isolated hydra mesoglea, fibronectin and type IV collagen. Under these conditions, nematocytes could be observed to migrate on some of these extracellular matrix components. By modifying previously described hydra grafting techniques, two procedures were developed to test specifically the role of extracellular matrix components during in vivo I-cell migration in hydra. In one approach, the extracellular matrix structure of the apical half of the hydra graft was perturbed using beta-aminopropionitrile and beta-xyloside. In the second approach, grafts were treated with fibronectin, RGDS synthetic peptide and antibody to fibronectin after grafting was performed. In both cases, I-cell migration from the basal half to the apical half of the grafts was quantitatively analyzed. Statistical analysis indicated that beta-aminopropionitrile, fibronectin, RGDS synthetic peptide and antibody to fibronectin all were inhibitory to I-cell migration as compared to their respective controls. beta-xyloside treatment had no effect on interstitial cell migration. These results indicate the potential importance of cell-extracellular matrix interactions during in vivo I-cell migration in hydra.
Collapse
Affiliation(s)
- X Zhang
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City 66160-7400
| | | |
Collapse
|
5
|
De Petrocellis L, Di Marzo V, Gianfrani C, Minei R. Arachidonic acid, protein kinase C activators and bud formation in Hydra vulgaris. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/0742-8413(93)90198-t] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|