Kimata K, Barrach H J, Brown K S, Pennypacker J P
J Biol Chem. 1981 Jul 10;256(13):6961-8.
Mice homozygous for the autosomal recessive gene, cartilage matrix deficiency (cmd/cmd), are characterized by disproportionate dwarfism and cleft palate. The collagen and proteoglycan of fetal limb cartilage was examined by biochemical and immunofluorescent techniques. While a normal amount of type II collagen was found, the amount of proteoglycan was reduced as determined by chemical analysis and incorporation of labeled precursors. Analyses of labeled proteoglycans by glycerol density gradient centrifugation under dissociative conditions and by gel filtration showed that the major high molecular weight proteoglycan characteristic of cartilage was absent, but smaller proteoglycans were present in normal amounts. Antibodies directed against proteoglycan core protein failed to stain the cmd/cmd cartilage while antibodies to type II collagen stained the cartilage without hyaluronidase pretreatment. Addition of beta-D-xyloside, an exogenous substrate for chondroitin sulfate synthesis, and direct assay for beta-D-xylosyltransferase activity indicated that cmd/cmd cartilage cells contained normal levels of the enzymes required for chondroitin sulfate synthesis. The data suggest that cmd/cmd is defective in the synthesis of the cartilage proteoglycan core protein.
常染色体隐性基因软骨基质缺乏（cmd/cmd）的纯合子小鼠表现为不成比例的侏儒症和腭裂。通过生化和免疫荧光技术检查了胎儿肢体软骨的胶原蛋白和蛋白聚糖。虽然发现II型胶原蛋白的量正常，但通过化学分析和标记前体的掺入确定蛋白聚糖的量减少。在解离条件下通过甘油密度梯度离心和凝胶过滤对标记的蛋白聚糖进行分析表明，软骨特有的主要高分子量蛋白聚糖不存在，但较小的蛋白聚糖含量正常。针对蛋白聚糖核心蛋白的抗体未能对cmd/cmd软骨进行染色，而针对II型胶原蛋白的抗体在未进行透明质酸酶预处理的情况下对软骨进行了染色。添加β-D-木糖苷（硫酸软骨素合成的外源底物）并直接测定β-D-木糖基转移酶活性表明，cmd/cmd软骨细胞含有硫酸软骨素合成所需的正常水平的酶。数据表明，cmd/cmd在软骨蛋白聚糖核心蛋白的合成中存在缺陷。
