J. Biol. Chem., Vol. 262, Issue 8, 3809-3812, 03, 1987
The dermatan sulfate proteoglycans of bovine sclera and their relationship to those of articular cartilage. An immunological and biochemical study
L Coster, LC Rosenberg, M van der Rest and AR Poole
Dermatan sulfate proteoglycans were isolated from adult bovine sclera and
adult bovine articular cartilage. Their immunological relationships were
studied by enzyme-linked immunosorbent assays using polyclonal antibodies
raised against the large and small dermatan sulfate proteoglycans from
sclera and a polyclonal and monoclonal antibody directed against the small
dermatan sulfate proteoglycans from cartilage. The small dermatan sulfate
proteoglycans from sclera and cartilage displayed immunological
cross-reactivity while there was no convincing evidence of shared
epitope(s) with the larger dermatan sulfate proteoglycans, nor did these
larger proteoglycans share any common epitopes with each other. A
hyaluronic acid binding region was detected immunologically on the larger
scleral dermatan sulfate proteoglycan but was absent from the larger
dermatan sulfate proteoglycan of cartilage and both the small dermatan
sulfate proteoglycans. These antibodies were used in immunofluorescence
microscopy to localize the scleral proteoglycans and molecules containing
these epitopes in the eye. The large scleral dermatan sulfate proteoglycan
was restricted to sclera while molecules related to the small scleral and
cartilage proteoglycans were found in the sclera, anterior uveal tract,
iris, and cornea. Amino acid sequencing of the amino-terminal regions of
the core proteins of the small dermatan sulfate proteoglycans from sclera
and articular cartilage showed that all the first 14 amino acids analyzed
were identical and the same as reported earlier for the small bovine skin
and tendon dermatan sulfate proteoglycans. These studies demonstrate that
the larger dermatan sulfate proteoglycans of sclera and cartilage are
chemically unrelated to each other and to the smaller dermatan sulfate
proteoglycans isolated from these tissues. The latter have closely related
core proteins and probably represent a molecule with a widespread
distribution in which the degree of epimerization of glucuronic acid and
iduronic acid varies between tissues.