scholarly journals Cell-free translation of messenger RNA for chondroitin sulphate proteoglycan core protein in rat cartilage

1984 ◽  
Vol 217 (1) ◽  
pp. 259-263 ◽  
Author(s):  
B M Vertel ◽  
W B Upholt ◽  
A Dorfman

Total RNA was extracted from the cartilage tissues rat Swarm chondrosarcoma, neonatal-rat breastplate and embryonic-chicken sterna and translated in wheat-germ cell-free reactions. The core protein of the chondroitin sulphate proteoglycan subunit was identified among translation products of rat mRNA by its apparent Mr of 330 000 and by its immunoprecipitation with specific antisera prepared against rat or chicken proteoglycan antigens. The apparent Mr of the rat proteoglycan core protein is 8000-10000 less than that of the equivalent chicken cartilage core-protein product.

1990 ◽  
Vol 272 (1) ◽  
pp. 193-199 ◽  
Author(s):  
M Pacifici

The mechanisms regulating the secretion of proteoglycans and collagens in chondrocytes, in particular those operating at the level of the rough endoplasmic reticulum (RER), are largely unknown. To examine these mechanisms, I studied the effects of acute ascorbate treatment on the secretion of two collagen types (types II and IX) and two proteoglycan types (PG-H and PG-Lb, the major keratan sulphate/chondroitin sulphate proteoglycan and the minor chondroitin sulphate proteoglycan respectively in cartilage) in scorbutic cultures of chick vertebral chondrocytes. I found that the scorbutic chondrocytes synthesized underhydroxylated precursors of types II and IX collagen that were secreted very slowly and accumulated in the RER. When the cultures were treated acutely with ascorbate, both macromolecules underwent hydroxylation within 1-1.5 h of treatment, and began to be secreted at normal high rates starting at about 2 h. Proteoglycan synthesis and secretion, however, remained largely unaffected by ascorbate treatment. Both the half-time of newly synthesized PG-H core protein in the RER and its conversion into completed proteoglycan were unchanged during treatment. Similarly, the overall rates of synthesis and secretion of both PG-H and PG-Lb remained at control levels during treatment. The data indicate that secretion of types II and IX collagen is regulated independently of secretion of PG-H and PG-Lb. This may be mediated by the ability of the RER of the chondrocyte to discriminate between procollagens and proteoglycan core proteins.


1991 ◽  
Vol 277 (1) ◽  
pp. 199-206 ◽  
Author(s):  
D J McQuillan ◽  
D M Findlay ◽  
A M Hocking ◽  
M Yanagishita ◽  
R J Midura ◽  
...  

The proteoglycans synthesized by an osteoblast-like cell line of rat origin (UMR 106-01) were defined after biosynthetic labelling with [35S]sulphate and [3H]glucosamine. Newly synthesized labelled proteoglycans were characterized by differential enzymic digestion in combination with analytical gel filtration and SDS/PAGE. UMR 106-01 cells were found to synthesize three major species of proteoglycan: a large chondroitin sulphate proteoglycan of Mr approximately 1 x 10(6), with a core protein of Mr approximately 350,000-400,000; a small chondroitin sulphate-containing species of Mr approximately 120,000 with a core protein of Mr 43,000; and a heparan sulphate proteoglycan of Mr approximately 150,000, with a core protein of Mr approximately 80,000. Over 70% of the newly synthesized intact proteoglycan species are associated with the cell layer of near-confluent cells; however, accessibility to trypsin digestion suggests an extracellular location. Chemical characteristics of the proteoglycans and preliminary mRNA hybridization indicate that the small chondroitin sulphate proteoglycan is probably PG II (decorin). The large chondroitin sulphate proteoglycan is most likely related to a hyaluronate-aggregating species from fibroblasts (versican), and the heparan sulphate proteoglycan bears striking similarities to cell-membrane-intercalated species described for a number of cell types.


1985 ◽  
Vol 229 (1) ◽  
pp. 63-71 ◽  
Author(s):  
B Smedsrød ◽  
L Kjellén ◽  
H Pertoft

Intravenously administered chondroitin sulphate, chemically labelled by [3H]acetylation of partially deacetylated polysaccharide, was taken up and degraded by the non-parenchymal cells of the liver. Studies using primary monolayer cultures of pure Kupffer cells, liver endothelial cells and parenchymal cells revealed that [3H]chondroitin sulphate was taken up and degraded by the liver endothelial cells only. Binding studies at 4 degrees C with [3H]chondroitin sulphate and 125I-chondroitin sulphate proteoglycan indicated that the glycosaminoglycan and the proteoglycan are recognized by the same binding sites on the liver endothelial cells. The ability of hyaluronic acid to compete with the labelled ligands for binding suggested that the binding site is identical with the recently described hyaluronate receptor on the liver endothelial cells [Smedsrød, Pertoft, Eriksson, Fraser & Laurent (1984) Biochem. J. 223, 617-626]. Fluorescein-labelled chondroitin sulphate proteoglycan accumulated in perinuclear vesicles of the liver endothelial cells, indicating that the proteoglycan is internalized and transported to the lysosomes. The finding that [3H]chondroitin sulphate and 125I-chondroitin sulphate proteoglycan were degraded by the liver endothelial cells to low-molecular-mass radioactive products suggested that both the polysaccharide chain and the core protein were catabolized by the cells.


Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1538 ◽  
Author(s):  
Marta Mellai ◽  
Laura Annovazzi ◽  
Ilaria Bisogno ◽  
Cristiano Corona ◽  
Paola Crociara ◽  
...  

Background: Neuron glial antigen 2 or chondroitin sulphate proteoglycan 4 (NG2/CSPG4) is expressed by immature precursors/progenitor cells and is possibly involved in malignant cell transformation. The aim of this study was to investigate its role on the progression and survival of sixty-one adult gliomas and nine glioblastoma (GB)-derived cell lines. Methods: NG2/CSPG4 protein expression was assessed by immunohistochemistry and immunofluorescence. Genetic and epigenetic alterations were detected by molecular genetic techniques. Results: NG2/CSPG4 was frequently expressed in IDH-mutant/1p19q-codel oligodendrogliomas (59.1%) and IDH-wild type GBs (40%) and rarely expressed in IDH-mutant or IDH-wild type astrocytomas (14.3%). Besides tumor cells, NG2/CSPG4 immunoreactivity was found in the cytoplasm and/or cell membranes of reactive astrocytes and vascular pericytes/endothelial cells. In GB-derived neurospheres, it was variably detected according to the number of passages of the in vitro culture. In GB-derived adherent cells, a diffuse positivity was found in most cells. NG2/CSPG4 expression was significantly associated with EGFR gene amplification (p = 0.0005) and poor prognosis (p = 0.016) in astrocytic tumors. Conclusion: The immunoreactivity of NG2/CSPG4 provides information on the timing of the neoplastic transformation and could have prognostic and therapeutic relevance as a promising tumor-associated antigen for antibody-based immunotherapy in patients with malignant gliomas.


1986 ◽  
Vol 235 (2) ◽  
pp. 469-479 ◽  
Author(s):  
B C Wightman ◽  
E A Weltman ◽  
L A Culp

Proteoglycans on the cell surface play critical roles in the adhesion of fibroblasts to a fibronectin-containing extracellular matrix, including the model mouse cell line Balb/c 3T3. In order to evaluate the biochemistry of these processes, long-term [35S]sulphate-labelled proteoglycans were extracted quantitatively from the adhesion sites of 3T3 cells, after their EGTA-mediated detachment from the substratum, by using an extractant containing 1% octyl glucoside, 1 M-NaCl and 0.5 M-guanidinium chloride (GdnHCl) in buffer with many proteinase inhibitors. Greater than 90% of the material was identified as a large chondroitin sulphate proteoglycan (Kav. = 0.4 on a Sepharose CL2B column), and the remainder was identified as a smaller heparan sulphate proteoglycan; only small amounts of free chains of glycosaminoglycan were observed in these sites. These extracts were fractionated on DEAE-Sepharose columns under two different sets of elution conditions: with acetate buffer (termed DEAE-I) or with acetate buffer supplemented with 8 M-urea (termed DEAE-II). Under DEAE-I conditions about one-half of the material was eluted as a single peak and the remainder required 4 M-GdnHCl in order to recover it from the column; in contrast, greater than 90% of the material was eluted as a single peak from DEAE-II columns. Comparison of the elution of [35S]sulphate-labelled proteoglycan with that of 3H-labelled proteins from these two columns, as well as mixing experiments, indicated that the GdnHCl-sensitive proteoglycans were trapped at the top of columns, partially as a consequence of their association with proteins in these adhesion-site extracts. Affinity chromatography of these proteoglycans on columns of either immobilized platelet factor 4 or immobilized plasma fibronectin revealed that most of the chondroitin sulphate proteoglycan and the heparan sulphate proteoglycan bound to platelet factor 4 but that only the heparan sulphate proteoglycan bound to fibronectin, providing a ready means of separating the two proteoglycan classes. Affinity chromatography on octyl-Sepharose columns to test for hydrophobic domains in their core proteins demonstrated that a high proportion of the heparan sulphate proteoglycan but none of the chondroitin sulphate proteoglycan bound to the hydrophobic matrix. These results are discussed in light of the possible functional importance of the chondroitin sulphate proteoglycan in the detachment of cells from extracellular matrix and in light of previous affinity fractionations of proteoglycans from the substratum-adhesion sites of simian-virus-40-transformed 3T3 cells.


2001 ◽  
Vol 39 (2) ◽  
pp. 99-104 ◽  
Author(s):  
Yoshihiro Abiko ◽  
Michiko Nishimura ◽  
Firoz Rahemtulla ◽  
Itaru Mizoguchi ◽  
Tohru Kaku

1984 ◽  
Vol 221 (3) ◽  
pp. 845-853 ◽  
Author(s):  
B Norling ◽  
B Glimelius ◽  
A Wasteson

A chondroitin sulphate proteoglycan capable of forming large aggregates with hyaluronic acid was identified in cultures of human glial and glioma cells. The glial- cell- and glioma-cell-derived products were mutually indistinguishable and had some basic properties in common with the analogous chondroitin sulphate proteoglycan of cartilage: hydrodynamic size, dependence on a minimal size of hyaluronic acid for recognition, stabilization of aggregates by link protein, and precipitability with antibodies raised against bovine cartilage chondroitin sulphate proteoglycan. However, they differed in some aspects: lower buoyant density, larger, but fewer, chondroitin sulphate side chains, presence of iduronic acid-containing repeating units, and absence (less than 1%) of keratan sulphate. Apparently the major difference between glial/glioma and cartilage chondroitin sulphate proteoglycans relates to the glycan rather than to the protein moiety of the molecule.


Sign in / Sign up

Export Citation Format

Share Document