Spatial and Temporal Expression Patterns in Animals

Müller, Werner

doi:10.1002/3527600906.mcb.200500041

Cited by 16 publications

(25 citation statements)

References 16 publications

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“…Stony corals are sometimes found on these spicules (Schulze 1904) suggesting a mutualistic (at least) symbiotic relationship. Recent molecular biological studies have revealed that the siliceous demosponges are provided with the genetic "toolkit" to construct these skeletal elements, the spicules, functional animals being composed of differentiated cells that interact in a tissue-like manner and that allow the formation of a body plan (Müller et al 2004;Müller 2005;Pilcher 2005). M. chuni is a siliceous sponge, belonging to the phylogenetically oldest Poriferan class, the Hexactinellida (Kruse et al 1997).…”

Section: Discussionmentioning

confidence: 99%

Formation of giant spicules in the deep-sea hexactinellid Monorhaphis chuni (Schulze 1904): electron-microscopic and biochemical studies

et al. 2007

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The siliceous sponge Monorhaphis chuni (Hexactinellida) synthesizes the largest biosilica structures on earth (3 m). Scanning electron microscopy has shown that these spicules are regularly composed of concentrically arranged lamellae (width: 3-10 μm). Between 400 and 600 lamellae have been counted in one giant basal spicule. An axial canal (diameter:~2 μm) is located in the center of the spicules; it harbors the axial filament and is surrounded by an axial cylinder (100-150 μm) of electron-dense homogeneous silica. During dissolution of the spicules with hydrofluoric acid, the axial filament is first released followed by the release of a proteinaceous tubule. Two major proteins (150 kDa and 35 kDa) have been visualized, together with a 24-kDa protein that cross-reacts with antibodies against silicatein. The spicules are surrounded by a collagen net, and the existence of a hexactinellidan collagen gene has been demonstrated by cloning it from Aphrocallistes vastus. During the axial growth of the spicules, silicatein or the silicatein-related protein is proposed to become associated with the surface of the spicules and to be finally internalized through the apical opening to associate with the axial filament. Based on the data gathered here, we suggest that, in the Hexactinellida, the growth of the spicules is mediated by silicatein or by a silicatein-related protein, with the orientation of biosilica deposition being controlled by lectin and collagen.

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Section: Discussionmentioning

confidence: 99%

Formation of giant spicules in the deep-sea hexactinellid Monorhaphis chuni (Schulze 1904): electron-microscopic and biochemical studies

et al. 2007

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“…Until now only indirect evidence suggested that arborescent demosponges grow according to a serial modular pattern (Müller, 2005). This conclusion was based on the spicule architecture and morphological observations.…”

Section: Discussionmentioning

confidence: 99%

“…7y). Therefore, the MRI microimages give valuable insight on a molecular base into the growth modules as described (Müller, 2005).…”

Section: Nmr Imagingmentioning

confidence: 99%

“…Therefore, it was postulated that silicic acid is an environmental morphogenetic compound. In concert with the genetic repertoire, e.g., the homeodomain transcription factors and T-box proteins, silicic acid of seawater establishes the oscular/apical-basal axis in sponges (Müller, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…Sponges have only an oscular/apical-basal axis (Müller, 2005); the oscule region can be considered as an organizer, since there organizer-speciWc genes are expressed, such as LIM-homeodomain, Brachyury, Frizzled receptor, noggin, and Iroquois. Especially in branching, arborescent sponges the oscular/apical-basal axis shows discrete identical, repetitive skeleton elements which we called serial modules (Müller, 2005). One module of a sponge with an anisotropic skeleton is composed of longitudinally arranged spicular bundles and is demarcated by tangential, interconnecting zones.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic resonance imaging of the siliceous skeleton of the demosponge Lubomirskia baicalensis

Müller

Kaluzhnaya

Беликов

et al. 2006

Journal of Structural Biology

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The skeletal elements (spicules) of the demosponge Lubomirskia baicalensis were analyzed; they are composed of amorphous, noncrystalline silica, and contain in a central axial canal the axial Wlament which consists of the enzyme silicatein. The axial Wlament, that orients the spicule in its longitudinal axis exists also in the center of the spines which decorate the spicule. During growth of the sponge, new serially arranged modules which are formed from longitudinally arranged spicule bundles are added at the tip of the branches. X-ray analysis revealed that these serial modules are separated from each other by septate zones (annuli). We describe that the longitudinal bundles of spicules of a new module originate from the apex of the earlier module from where they protrude. A cross section through the oscular/apical-basal axis shows that the bundle rays are organized in a concentric and radiate pattern. High resolution magnetic resonance microimaging studies showed that the silica spheres of the spicules in the cone region contain high amounts of 'mobile' water. We conclude that the radiate accretive growth pattern of sponges is initiated in the apical region (cones) by newly growing spicules which are characterized by high amounts of 'mobile' water; subsequently spicule bundles are formed laterally around the cones. 

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Silicate modulates the cross‐talk between osteoblasts (SaOS‐2) and osteoclasts (RAW 264.7 cells): Inhibition of osteoclast growth and differentiation

Schröder

Wang

Wiens

et al. 2012

J of Cellular Biochemistry

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It has been shown that inorganic monomeric and polymeric silica/silicate, in the presence of the biomineralization cocktail, increases the expression of osteoprotegerin (OPG) in osteogenic SaOS-2 sarcoma cells in vitro. In contrast, silicate does not affect the steady-state gene expression level of the osteoclastogenic ligand receptor activator of NF-κB ligand (RANKL). In turn it can be expected that the concentration ratio of the mediators OPG/RANKL increases in the presence of silicate. In addition, silicate enhances the growth potential of SaOS-2 cells in vitro, while it causes no effect on RAW 264.7 cells within a concentration range of 10-100 µM. Applying a co-cultivation assay system, using SaOS-2 cells and RAW 264.7 cells, it is shown that in the presence of 10 µM silicate the number of RAW 264.7 cells in general, and the number of TRAP(+) RAW 264.7 cells in particular markedly decreases. The SaOS-2 cells retain their capacity of differential gene expression of OPG and RANKL in favor of OPG after exposure to silicate. It is concluded that after exposure of the cells to silicate a factor(s) is released from SaOS-2 cells that causes a significant inhibition of osteoclastogenesis of RAW 264.7 cells. It is assumed that it is an increased secretion of the cytokine OPG that is primarily involved in the reduction of the osteoclastogenesis of the RAW 264.7 cells. It is proposed that silicate might have the potential to stimulate osteogenesis in vivo and perhaps to ameliorate osteoporotic disorders.

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Spatial and Temporal Expression Patterns in Animals

Cited by 16 publications

References 16 publications

Formation of giant spicules in the deep-sea hexactinellid Monorhaphis chuni (Schulze 1904): electron-microscopic and biochemical studies

Formation of giant spicules in the deep-sea hexactinellid Monorhaphis chuni (Schulze 1904): electron-microscopic and biochemical studies

Magnetic resonance imaging of the siliceous skeleton of the demosponge Lubomirskia baicalensis

Silicate modulates the cross‐talk between osteoblasts (SaOS‐2) and osteoclasts (RAW 264.7 cells): Inhibition of osteoclast growth and differentiation

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