The hydroid <i>Hydractinia</i>: a versatile, informative cnidarian representative

Frank, Uri; Leitz, Thomas; Müller, Werner A.

doi:10.1002/bies.1137

Cited by 98 publications

(57 citation statements)

References 46 publications

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“…In mature colonies, CEL expression resumed but was restricted to only few cells. A Hydractinia colony is mainly composed of two polyp types, feeding polyps (gastrozooids) and sexual polyps (gonozooids), both emerging from the gastrovascular network, the stolons (Frank et al, 2001). Sexual polyps do not feed but contain the gonads.…”

Section: Analysis Of Cel Spatial Expression By In Situ Hybridizationmentioning

confidence: 99%

“…Two North Atlantic sibling species, H. echinata and H. symbiolongicarpus have been studied since decades, mainly in the context of development and allorecognition (Frank et al, 2001). Hydractinia's stem cells, called interstitial cells or i-cells, are pluripotent and are repeated carbohydrate recognition domains (CRD) of about 95 amino acid residues including eight conserved cysteines (Hosono et al, 1999).…”

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confidence: 99%

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

Mali¹,

Millane²,

Plickert³

et al. 2011

Int. J. Dev. Biol.

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We have identified a novel, multidomain, polymorphic lectin in the marine cnidarian Hydractinia echinata. The gene is expressed in oocytes and was therefore named CEL for cnidarian egg lectin. The predicted protein has an unusual domain architecture, consisting of variable numbers of thrombospondin type 1 domains, flanked by one N-terminal and two C-terminal galactose binding lectin domains. The diversity of the gene's transcripts results from allelic polymorphism as well as alternative splicing. Hydractinia is dioecious and its sex has been reported previously to be genetically determined. We found intersexual colonies that were functional males, but had immature CEL-positive oocytes alongside mature sperm in the same gonads. Intersexuality was observed to be common in one population but not found in others. Hermaphroditic, self-fertile colonies were found in one locality; however, in these cases gonads contained either male or female gametes without mixed ones. Intersexuality that was considered to be a very rare event is apparently a more common phenomenon, at least in some populations. True hermaphroditism also occurs in this species. CEL can be considered as a marker for early oocyte differentiation and may play a role in germ cell specification and sex determination in cnidarians.

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Section: Analysis Of Cel Spatial Expression By In Situ Hybridizationmentioning

confidence: 99%

mentioning

confidence: 99%

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

Mali¹,

Millane²,

Plickert³

et al. 2011

Int. J. Dev. Biol.

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“…The availability of mutants is one of the features fostering the choice of Hydractinia echinata (Cnidaria: Hydrozoa) as a cnidarian model organism in studies on the evolution of genes, developmental mechanisms, and allorecognition (Frank et al, 2001). Hydractinia is a colonial species; the colony consists of hydra-like feeding polyps (gastrozooids) and sexual polyps (gonozooids); these polyps are all interconnected with each other through a network of gastro-vascular channels, termed stolons.…”

Section: Introductionmentioning

confidence: 99%

Patterning a multi-headed mutant in Hydractinia: enhancement of head formation and its phenotypic normalization.

Müller

Teo²,

Möhrlen³

2004

Int. J. Dev. Biol.

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In a mutant strain of Hydractinia (Cnidaria: Hydrozoa), the polyps develop ectopic supernumerary tentacles and heads (hypostomes) after an initial phase of wild-type growth. In order to elucidate the molecular mechanisms implicated in the development of aberrant phenotypes, we tried to enhance or suppress the expressivity of this hypomorphic mutation by exposing subclones to factors supposedly influencing pattern formation. Upon iterated treatment with alsterpaullone, an inhibitor of GSK-3, the formation of additional, ectopic head structures and the budding of new polyps were dramatically accelerated and enhanced. The endogenous stoloninducing factor (SIF) had opposite effects by reducing head forming potential while increasing stolon-forming potential. SIF could be used to rescue extremely aberrant phenotypes. In these mutant colonies, long polyps with multiple heads eventually detach from stolons and lose the ability to regenerate stolons. Upon exposure to SIF, such free-floating multi-headed polyps resumed production of stolons and acquired wild-type morphology. We conclude that a canonical WNT signaling cascade is involved in patterning the body axis of polyps and in the initiation of budding, and that SIF counteracts this signaling system.

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“…Basic knowledge about processes acting downstream of the induction of metamorphosis is available (for review see Frank et al, 2001;Müller and Leitz, 2002). Neurosensory cells transfer internally the external signal via the phosphatidyl-inositol-PKC transduction cascade (Leitz and Müller, 1987).…”

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confidence: 99%