Biosynthesis and molecular biology of the secretory proteins of the subcommissural organ

Nualart, Francisco; Hein, Silvia

doi:10.1002/1097-0029(20010301)52:5<468::aid-jemt1033>3.0.co;2-u

Cited by 14 publications

(21 citation statements)

References 66 publications

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“…(3) Classical SCO glycoproteins secreted into CSF (i.e. pre-RF or RF proper) has been reported as being Con-A-negative (Hein et al 1993;Nualart and Hein 2001). However, the AFRU-positive CSF compound of 66 kDa has moderate affinity for this lectin, thereby indicating a source different to SCO cells.…”

Section: Csf-soluble Sco Secretory Materialsmentioning

confidence: 99%

“…SCO ependymal cells are specialized in the synthesis and secretion of high-molecular-mass glycoproteins that are released into the cerebrospinal fluid (CSF), where they aggregate to form a threadlike supramolecular structure known as Reissner's fiber (RF; Oksche 1969; E.M. Rodriguez et al 1992Rodriguez et al , 1998A. Meiniel 2001;Nualart and Hein 2001). In the encephalon, the glycoproteins forming the RF can be found in two conformations:…”

Section: Introductionmentioning

confidence: 99%

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Continuous delivery of a monoclonal antibody against Reissner’s fiber into CSF reveals CSF-soluble material immunorelated to the subcommissural organ in early chick embryos

et al. 2006

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The subcommissural organ (SCO) is an ependymal differentiation located in the dorsal midline of the caudal diencephalon under the posterior commissure. SCO cells synthesize and release glycoproteins into the cerebrospinal fluid (CSF) forming a threadlike structure known as Reissner's fiber (RF), which runs caudally along the ventricular cavities and the central canal of the spinal cord. Numerous monoclonal antibodies have been raised against bovine RF and the secretory material of the SCO. For this study, we selected the 4F7 monoclonal antibody based on its cross-reactivity with chick embryo SCO glycoproteins in vivo. E4 chick embryos were injected with 4F7 hybridoma cells or with the purified monoclonal antibody into the ventricular cavity of the optic tectum. The hybridoma cells survived, synthesized and released antibody into the CSF for at least 13 days after the injection. E5 embryos injected with 4F7 antibody displayed precipitates in the CSF comprising both the monoclonal antibody and anti-RF-positive material. Such aggregates were never observed in control embryos injected with other monoclonal antibodies used as controls. Western blot analysis of CSF from E4-E6 embryos revealed several immunoreactive bands to anti-RF (AFRU) antibody. We also found AFRU-positive material bound to the apical surface of the choroid plexus primordia in E5 embryos. These and other ultrastructural evidence suggest the existence of soluble SCO-related molecules in the CSF of early chick embryos.

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Section: Csf-soluble Sco Secretory Materialsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Continuous delivery of a monoclonal antibody against Reissner’s fiber into CSF reveals CSF-soluble material immunorelated to the subcommissural organ in early chick embryos

et al. 2006

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“…It has been postulated that RF is formed by two different protein complexes, one of them containing a 450-kDa glycoprotein (SCOspondin) derived from a precursor form of 540 kDa (Nualart et al 1991). In the last few years, the full sequence of the mRNA encoding for the SCO-spondin precursor has been determined Gobron et al 1996;Nualart et al 1998;Didier et al 2000;Meiniel 2001;Nualart and Hein 2001). Thus, important structural and functional clues to the SCO-spondin polypeptide have been elucidated.…”

Section: Introductionmentioning

confidence: 99%

Bovine floor plate explants secrete SCO-spondin

Guinazu

Richter

Rodríguez

2002

Cell and Tissue Research

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SCO-spondin is a large-molecular mass glycoprotein, secreted by the subcommissural organ (SCO), which has been implicated in neuronal development during ontogeny of the central nervous system. The expression of SCO-spondin is not restricted to the SCO but it also occurs in the floor plate, a key structure participating in neuronal differentiation and patterning of the neural tube. It has been postulated that SCO-spondin detected in the floor plate is released into the lumen of the neural tube, but this new route of secretion of floor plate cells needs to be further substantiated. For this purpose, we standardized long-term organ culture of bovine floor plate and performed morphological, immunological, biochemical, and gene expression analyses. The study of floor plate explants and their conditioned media allowed us to demonstrate that: (1) organ-cultured floor plate cells are actively secretory for up to 25 days; (2) SCO-spondin gene is actively transcribed and translated by the cultured floor plate cells; (3) SCO-spondin is released into the culture medium via the apical cell pole; and (4) upon release, SCO-spondin does not aggregate in the conditioned medium but remains soluble. Furthermore, in the cultured floor plate cells, SCO-spondin may be secreted through a route bypassing the Golgi apparatus.

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“…The SCO is an ancient and phylogenetically conserved structure that is present throughout the vertebrate subphylum (Oksche 1961). SCO ependymal cells are specialized in the synthesis and secretion of highmolecular-mass glycoproteins that are released into the cerebrospinal fluid (CSF), where they aggregate to form a threadlike supramolecular structure known as Reissner's fibre (RF; Oksche 1969;Rodriguez et al 1992Rodriguez et al , 1998Meiniel 2001;Nualart and Hein 2001). Part of the SCO secretion may remain soluble in the CSF, under both physiological and experimental conditions (Irigoin et al 1990;Lehmann et al 1993;Rodriguez et al 1993;HoyoBecerra et al 2006;Vio et al 2008).…”

Section: Introductionmentioning

confidence: 99%

The subcommissural organ and the development of the posterior commissure in chick embryos

et al. 2009

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The subcommissural organ (SCO) is an ependymal differentiation located in the diencephalon under the posterior commissure (PC). SCO-spondin, a glycoprotein released by the SCO, belongs to the thrombospondin superfamily and shares molecular domains with axonal pathfinding molecules. Several lines of evidence suggest a relationship between the SCO and the development of the PC in the chick: (1) their close location to each other, (2) their differentiation at the same developmental stage in the chick, (3) the abnormal PC found in null mutants lacking an SCO and (4) the release by the SCO of SCO-spondin. By application of DiI crystals in the PC of chick embryos, we have identified the neurons that give rise to the PC. Labelling is confined to the magnocellular nucleus of the PC (MNPC). To gain insight into the role of the SCO in PC development, coculture experiments of explants of the MNPC region (MNPCr) from embryos at embryonic day 4 (E4) with SCO explants from E4 or E13 embryos have been performed and the neurite outgrowth from the MNPCr explants has been analysed. In the case of coculture of E4 MNPCr with E4 SCO, the number of neurites growing from the MNPCr is higher at the side facing the SCO. However, when E4 MNPCr and E13 SCO are cocultured, the neurites grow mostly at the side opposite to the SCO. These data suggest that, at early stages of development, the SCO releases some attractive or permissive molecule(s) for the growing of the PC, whereas at later stages, the SCO has a repulsive effect over neurites arising from MNPCr.

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Biosynthesis and molecular biology of the secretory proteins of the subcommissural organ

Cited by 14 publications

References 66 publications

Continuous delivery of a monoclonal antibody against Reissner’s fiber into CSF reveals CSF-soluble material immunorelated to the subcommissural organ in early chick embryos

Continuous delivery of a monoclonal antibody against Reissner’s fiber into CSF reveals CSF-soluble material immunorelated to the subcommissural organ in early chick embryos

Bovine floor plate explants secrete SCO-spondin

The subcommissural organ and the development of the posterior commissure in chick embryos

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