Proteoglycan biosynthesis by chick embryo retina glial-like cells.
In this report we present biochemical evidence that purified cultures of chick embryo retina glial-like cells actively synthesize heparan sulfate (HS) and chondroitin sulfate/dermatan sulfate (CS/DS) proteoglycans as well as hyaluronic acid. Glial-like cell cultures were metabolically labeled with [3H]glucosamine and 35SO4, and the medium, cell layer, and substratum-bound fractions were analyzed separately. Proteoglycans were characterized according to charge, apparent molecular size, and glycosaminoglycan (GAG) composition and were found to be differentially distributed among the cellular compartments. HS was the predominant GAG overall and was the major species found in the cell layer and substratum-bound fractions. CS/DS was also present in each fraction and comprised the largest proportion of GAGs in the medium. The major GAG-containing material resolved into three different size classes. The first, found in the cell layer and substratum-bound fractions, contained both CS/DS and HS and was of large size. A second, intermediately sized class with a higher CS/DS:HS ratio was found in the medium. The smallest class was found in the cell layer fraction and comprised HS, most likely present as free GAG chains. In addition, each fraction contained hyaluronic acid. Characteristics of these macromolecules differ from those produced by purified cultures of chick embryo retina neurons and photoreceptors in terms of size, compartmental distribution, and presence of hyaluronic acid.
Threlkeld
A
A
Retinal Degenerations Research Center, Wilmer Ophthalmological Institute, Johns Hopkins University, Baltimore, Maryland 21205.
Adler
R
R
Hewitt
A T
AT
D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D002808:Chondroitin Lyases / Q000378:metabolism; D002809:Chondroitin Sulfates / Q000096:biosynthesis; D002845:Chromatography; D002851:Chromatography, High Pressure Liquid; D003871:Dermatan Sulfate / Q000096:biosynthesis; D005944:Glucosamine / Q000378:metabolism; D006025:Glycosaminoglycans / Q000032:analysis; D006497:Heparan Sulfate / Q000096:biosynthesis; D006820:Hyaluronic Acid / Q000096:biosynthesis; D006821:Hyaluronoglucosaminidase / Q000378:metabolism; D008970:Molecular Weight; D009457:Neuroglia / Q000378:metabolism*; D009608:Nitrous Acid; D010206:Papain / Q000378:metabolism; D011509:Proteoglycans / Q000096:biosynthesis*; D012160:Retina / Q000166:cytology / Q000196:embryology*; D013431:Sulfates / Q000378:metabolism; D014018:Tissue Distribution
D002808:Chondroitin Lyases; D002809:Chondroitin Sulfates; D003871:Dermatan Sulfate; D005944:Glucosamine; D006025:Glycosaminoglycans; D006497:Heparan Sulfate; D006820:Hyaluronic Acid; D006821:Hyaluronoglucosaminidase; D009608:Nitrous Acid; D010206:Papain; D011509:Proteoglycans; D013431:Sulfates