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The freshwater cnidarian Hydra was first described in 1702 and has been the object of study for 300 years. Experimental studies of Hydra between 1736 and 1744 culminated in the discovery of asexual reproduction of an animal by budding, the first description of regeneration in an animal, and successful transplantation of tissue between animals. Today, Hydra(More)
The finding that the metazoan hypoxic response is regulated by oxygen-dependent posttranslational hydroxylations, which regulate the activity and lifetime of hypoxia-inducible factor (HIF), has raised the question of whether other hydroxylases are involved in the regulation of gene expression. We reveal that the splicing factor U2 small nuclear(More)
Many of the major pathways that govern early development in higher animals have been identified in cnidarians, including the Wnt, TGFbeta and tyrosine kinase signaling pathways. We show here that Notch signaling is also conserved in these early metazoans. We describe the Hydra Notch receptor (HvNotch) and provide evidence for the conservation of the Notch(More)
Apoptosis is a normal process by which cells die and are eliminated from tissue by phagocytosis [1]. It is involved in regulating cell numbers in adult tissues and in eliminating 'excess' cells during embryogenesis and development. Apoptosis is mediated by activation of caspases, which then cleave a variety of cellular substrates and thereby cause the(More)
Programmed cell death occurs in most, if not all life forms. It is used to sculpt tissue during embryogenesis, to remove damaged cells, to protect against pathogen infection and to regulate cell numbers and tissue homeostasis. In animals cell death often occurs by a morphologically and biochemically conserved process called apoptosis. A novel group of(More)
BACKGROUND Apoptotic cell death plays an essential part in embryogenesis, development and maintenance of tissue homeostasis in metazoan animals. The culmination of apoptosis in vivo is the phagocytosis of cellular corpses. One morphological characteristic of cells undergoing apoptosis is loss of plasma membrane phospholipid asymmetry and exposure of(More)
Hydra is one of the simplest metazoans and thus an important model organism for studies on the evolution of developmental mechanisms in multi-cellular animals. In Hydra apoptosis is involved in the regulation of cell numbers in response to feeding, in regeneration and in the removal of non-self cells. It also participates in the maintenance of cellular(More)
BACKGROUND The transcriptional activation function of the p53 tumour suppressor protein is induced by DNA damage and results in growth arrest and/or apoptotic responses. A key component of this response is the dramatic rise in p53 protein concentration resulting from an increase in the protein's stability. Very recently, it has been suggested that(More)
Hydra is a member of the ancient metazoan phylum Cnidaria and is an especially well investigated model organism for questions of the evolutionary origin of metazoan processes. Apoptosis in Hydra is important for the regulation of cellular homeostasis under different conditions of nutrient supply. The molecular mechanisms leading to apoptosis in Hydra are(More)
Boundary formation is an important mechanism of development and has been studied in a number of bilaterian model organisms where it is often controlled by Notch, FGF and Wnt signalling. Tissue boundaries are also formed in simple pre-bilaterian animals. The boundary between parent and bud during asexual reproduction in the fresh water polyp Hydra vulgaris(More)