Extracellular proteins of goldfish optic tectum labeled by intraocular injection of 3H-proline

Thormodsson, Finnbogi R.; Antonian, Edna; Grafstein, Bernice

doi:10.1016/0014-4886(92)90135-d

Cited by 13 publications

(7 citation statements)

References 37 publications

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“…Moreover, the meninges secrete a glycoprotein, ependymin (Shashoua 1991;Hoffmann 1992), which has been implicated in neural regeneration. Increased levels of ependymin synthesis are observed in the regenerating goldfish optic nerve (Thormodsson et al 1992), while the sharpening of the regenerating retinotectal projection is blocked by infusion of ependymin antibodies (Schmidt and Shashoua 1988).…”

Section: Formation Of a Scar?mentioning

confidence: 97%

The meningeal sheath of the regenerating spinal cord of the eel, Anguilla

Dervan

Roberts

2003

Anatomy and Embryology

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We describe here the meningeal sheath that encloses the spinal cord, and the sheath that develops when the cord regenerates after a total transection. This description is derived from electron and light microscopy. The sheath of the uninjured cord was found to be a single structure of two parts: an outer, thin melanocyte layer and an inner, thicker layer of 2 to 10 rows of fibroblasts, closely associated with collagen and elastic fibers. Soon after cord transection, the injured axons re-grow and, together with the reforming central canal, create a bridge that links the transected cord within 8 days of injury. This bridge is covered at first by a rudimentary meningeal sheath, formed of fibroblasts and macrophages, that later progressively thickens and becomes more compact. By about day 20, the fibroblasts are arranged as 16 to 20 loose rows that include bundles of collagen, oriented along the rostro-caudal axis of the cord. Even after 144 days, the meninx, although substantially thicker than normal because of the numerous fibroblast rows (20 to 30), still lacks the melanocyte layer. In cases in which the meninx at the transection site was mechanically and pharmacologically (6-hydroxydopamine) disrupted, bridge formation was essentially unchanged, and axonal regrowth continued; some regrowing axons, however, extruded from the denuded cord. Accordingly, our findings indicate that although the meningeal sheath is not essential for cord regeneration to take place, it may well facilitate recovery by providing mechanical guidance and support to the regrowing axons.

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Section: Formation Of a Scar?mentioning

confidence: 97%

The meningeal sheath of the regenerating spinal cord of the eel, Anguilla

Dervan

Roberts

2003

Anatomy and Embryology

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“…Ependymins, erroneously named after their first immunohistochemical localization in goldfish ependymal zones (Shashoua, 1985), are secretory glycoproteins of the endomeninx (Konigslorfcr et al, 1990;Sterrer et al, 1990;Rinder et al, 1992;Schwarz et al, 1993). Soluble forms represent the predominant constituents of the cerebrospinal fluid (CSF) of some orders of teleost fish (HolTmann, 1992) and a bound form is associated with the extracellular matrix (Thormodsson et al, 1992a;Schwarz et al, 1993). Ependyinins are not well conserved during evolution (Miiller-Schmid et al, 1992 and, thus far, on the basis of structure no homologous proteins have been characterized in mammals.…”

mentioning

confidence: 99%

“…goldfish ependymins bear the L2/HNK-1 epitope (Shashoua et al, 1986) which is also found on various neural cell-adhesion molecules and human natural killer cells (Kunemund et al, 1988). This connection to adhesive processes is interesting with respect to the presumed dual existence of ependymins in a soluble and a bound form (Thormodsson et al, 1992a;Schwarz et al, 1993) which is reminiscent of fibronectin (Yamada, 1982). Since self-assembly of the extracellular matrix is a Ca'+-dependent process (Yurchenco and Schittny, 1990;Paulswn, 1992), association of ependymins with bundles of collagen fibrils (Schwarz et al, 1993) could also be triggered by their Ca'+ binding similar to osteonectitd SPARCBM-40 (Sage et a].. 1989;Maurer et al, 1992).…”

mentioning

confidence: 99%

“…Soluble forms represent the predominant constituents of the cerebrospinal fluid (CSF) of some orders of teleost fish (HolTmann, 1992) and a bound form is associated with the extracellular matrix (Thormodsson et al, 1992a;Schwarz et al, 1993). Ependyinins are not well conserved during evolution (MiillerSchmid et al, 1992(MiillerSchmid et al, , 1993 and, thus far, on the basis of structure no homologous proteins have been characterized in mammals.…”

mentioning

confidence: 99%

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Calcium binding to sialic acids and its effect on the conformation of ependymins

Ganß

Hoffmann

1993

European Journal of Biochemistry

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Soluble ependymins form the predominant protein constituents in the cerebrospinal fluid from many orders of teleost fish. Furthermore, these glycoproteins also exist in a bound form associated with the extracellular matrix. Ependymins are synthesized in meningeal fibroblasts. In goldfish, their synthesis is increased during the regeneration of the optic nerve and they share several characteristics with molecules involved in cell contact phenomena. In this study, we show by a calcium overlay technique that ependymins from goldfish and rainbow trout are able to bind 45Ca2+. However, nearly all of this Ca2+‐binding capacity is lost after digestion with sialidase. Furthermore, circular‐dichroism spectra from FPLC‐purified rainbow trout ependymins have been recorded in the presence and absence of Ca2+. Below 250 nm, the CD spectrum showed a characteristic minimum of ellipticity at 217 nm typical of β structures. This signal is independent of the Ca2+ concentration. In contrast, the complex signal at 250–310 nm mainly decreased with increasing Ca2+ concentration indicating changes in the environment of aromatic side chains.

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“…However, ependymins are also attracting increasing interest because they share several characteristics with glycoproteins involved in cell contact phenomena [1]. For example, in the goldfish, infusion of ependymin antibodies blocks the sharpening of the regenerating retinotectal projection [16], and increased synthesis of ependymins in the optic nerve has been reported during its regeneration [17]. Generally, an anti-adhesive potential of ependymins would be in agreement with their synthesis in the endomeninx, where they could be responsible for a diffuse projection of posthatching retinal axons [1].…”

Section: Introductionmentioning

confidence: 99%

Calcium-Induced Conformational Transition of Trout Ependymins Monitored by Tryptophan Fluorescence

Ganß¹,

Hoffmann²

2009

Open Biochem J

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Ependymins are secretory, calcium-binding sialoproteins which are the predominant constituents of the cerebrospinal fluid of many teleost fish. A bound form of these regeneration-responsive glycoproteins is associated with collagen fibrils of the extracellular matrix. Here, the tryptophan fluorescence of ependymins was monitored at various Ca2+ concentrations. Two distinct states were identified with a relatively sharp transition at about 1 mM Ca2+. In agreement with previous circular dichroism measurements, this strongly supports the hypothesis that a calcium-induced conformational change is important for the interaction of ependymins with components of the extracellular matrix. Such interactions with constituents of various basal laminae would also explain the important roles of piscine ependymins as well as invertebrate and mammalian ependymin-related proteins for cell adhesion processes and cell migration.

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Extracellular proteins of goldfish optic tectum labeled by intraocular injection of 3H-proline

Cited by 13 publications

References 37 publications

The meningeal sheath of the regenerating spinal cord of the eel, Anguilla

The meningeal sheath of the regenerating spinal cord of the eel, Anguilla

Calcium binding to sialic acids and its effect on the conformation of ependymins

Calcium-Induced Conformational Transition of Trout Ependymins Monitored by Tryptophan Fluorescence

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