Changes in perlecan during chondrocyte differentiation in the fetal bovine rib growth plate.
Perlecan is a heparan sulfate proteoglycan present in the growth plate and essential for endochondral ossification. We evaluated the synthesis and structure of perlecan in the different zones of the growth plate. The growth plates from fetal bovine ribs were isolated and sequentially sliced into 1-mm sections containing the hypertrophic zone, lower proliferative zone, upper proliferative zone, intermediate zone, and resting zone, respectively. The slices were then either incubated in culture medium with 35SO4 to measure total sulfated proteoglycan synthesis and perlecan synthesis, extracted for perlecan core protein analysis by Western blot, or extracted for perlecan isolation and subsequent characterization of glycosaminoglycan size and disaccharide composition. 35SO4 incorporation into perlecan was three-fourfold higher in the proliferating/hypertrophic zone than the resting zone. Western blot showed perlecan content was greatest in the lower and upper proliferating zones and that a perlecan fragment lacking portions of the N- and C-terminal domains containing heparan sulfate was also present in all zones. Purified perlecan from the hypertrophic/lower proliferative zone had larger chondroitin sulfate chains and a different composition of CS and HS disaccharides than the perlecan isolated from the resting zone. These results indicate perlecan deposition is increased and is turned over during proliferation to be replaced by a perlecan with a different sulfation pattern.
West
Leigh
L
Center for Research in Skeletal Development and Pediatric Orthopaedics, Shriners Hospitals for Children-Tampa, 12502 Pine Drive, Tampa, Florida 33612, USA.
Govindraj
Prasanthi
P
Koob
Thomas J
TJ
Hassell
John R
JR
D000818:Animals; D015153:Blotting, Western; D002417:Cattle; D002454:Cell Differentiation / Q000502:physiology*; D049109:Cell Proliferation; D019902:Chondrocytes / Q000166:cytology* / Q000378:metabolism; D004247:DNA / Q000032:analysis / Q000096:biosynthesis; D006132:Growth Plate / Q000166:cytology* / Q000196:embryology / Q000378:metabolism; D019812:Heparan Sulfate Proteoglycans / Q000737:chemistry / Q000378:metabolism*; D007124:Immunoenzyme Techniques; D009924:Organ Culture Techniques; D012272:Ribs / Q000196:embryology*; D013431:Sulfates / Q000378:metabolism
D019812:Heparan Sulfate Proteoglycans; D013431:Sulfates; C071927:perlecan; D004247:DNA