Partial cDNA sequence encoding a globular domain at the C terminus of the rat cartilage proteoglycan

We have isolated and sequenced a cDNA clone of 872 base pairs from the 3' end of the mRNA for the large cartilage specific proteoglycan from rat. Identification was confirmed by a comparison with published protein sequence. Hybridization analysis shows the presence of an 8-9-kilobase mRNA for this proteoglycan in rat and chick sternal chondrocytes and rat chondrosarcoma cells, but not in RNA from rat fibroblasts, vitamin A-treated chick chondrocytes, chick crop, or bone. The carboxyl portion of the proteoglycan is deduced to terminate in a globular domain, which includes a region homologous to a chick hepatic lectin, and is possibly involved in binding to N-acetylglucosamine. The clone extends into a region where serines are clustered, probably the start of the chondroitin sulfate-rich region.