Totipotent migratory stem cells in a hydroid

Abstract

Hydroids, members of the most ancient eumetazoan phylum, the Cnidaria, harbor multipotent, migratory stem cells lodged in interstitial spaces of epithelial cells and are therefore referred to as interstitial cells or i-cells. According to traditional understanding, based on studies in Hydra, these i-cells give rise to several cell types such as stinging cells, nerve cells, and germ cells, but not to ectodermal and endodermal epithelial cells; these are considered to constitute separate cell lineages. We show here that, in Hydractinia, the developmental potential of these migratory stem cells is wider than previously anticipated. We eliminated the i-cells from subcloned wild-type animals and subsequently introduced i-cells from mutant clones and vice versa. The mutant donors and the wild-type recipients differed in their sex, growth pattern, and morphology. With time, the recipient underwent a complete conversion into the phenotype and genotype of the donor. Thus, under these experimental conditions the interstitial stem cells of Hydractinia exhibit totipotency.

A polymorphic, thrombospondin domain-containing lectin is an oocyte marker in Hydractinia: implications for germ cell specification and sex determination

“…Intersexuality, expressed as single oocytes in functional male gonads, has been reported to be a rare genetic mutation in this species (Hauenschild, 1954), or be the result of allogeneic stem cell invasion of the opposite sex following natural or experimental grafting of male and female histocompatible colonies (Müller, 1967;Müller, 1964;Müller et al, 2004). Our results, using laboratory reared offspring from field-sampled animals and therefore non-chimeric, show that intersexuality is actually quite common in males, at least in the Sylt population.…”

“…Rhamnospondin, in contrast, also contains the combination of TSP1 repeats and galactose binding lectin domains, but the overall structure of CEL is different. CEL, therefore, has a unique structure that has not been reported previously, but primarily located in the epithelial interstices of the gastrovascular system of the adults, called stolons (Müller et al, 2004). I-cells can migrate into newly growing parts of the colony where they differentiate into somatic and germ cells.…”

Hydractinia, a pioneering model for stem cell biology and reprogramming somatic cells to pluripotency

“…Most observations and investigations on stem cells in Cnidaria have been made in Hydra (reviewed by Bode, 1996;Bosch, 2007Bosch, , 2009Bosch et al, 2010;Watanabe et al, 2009;David 2012;Hobmayer 2012 in this issue) and in Hydractinia (Weismann, 1883;Hoffmann and Kroiher, 2001;Müller et al, 2004a;Teo et al, 2006;Rebscher et al, 2008;Künzel et al, 2010;Millane et al, 2011). The stem cells are also known as interstitial cells (i-cells) as they reside in interstitial spaces at the bases of the epithelia (Weismann, 1883).…”

“…5C). Interstitial stem cells can be labelled with bromodeoxyuridine (BrdU) and tracked during migration and differentiation Teragawa and Bode, 1990;Müller et al, 2004a). By using transgene technologies in Cnidaria (Miljkovicet al, 2002;Böttger et al, 2002;Wittlieb et al, 2006, Kalthurin et al, 2007Künzel et al, 2010), the origin, migratory behaviour, multiplication and differentiation of i-cells can now be traced in living animals.…”

Scleractinian coral cell proliferation is reduced in primary culture of suspended multicellular aggregates compared to polyps

“…Within the phylum Cnidaria, this method is commonly used in hydrozoans, for example in the marine species Hydractinia echinata and Clytia hemisphaerica, in short-term pulse (5 mM BrdU for 30 min to a few hours)-chase assays to detect mitotic activity and cellular self-renewal (Müller et al 2004;Denker et al 2008). In adult colonies of scleractinian corals the BrdU labeling method has recently been used, at much lower concentrations and longer exposure periods, to investigate cell proliferation activity in aquariumbased studies.…”