Analysis of clones from a human cartilage cDNA library provides insight into chondrocyte gene expression and identifies novel candidate genes for the osteochondrodysplasias

To begin to define the gene expression pattern in fetal cartilage and to identify uncharacterized candidate genes for the osteochondrodysplasias, we analyzed clones from a fetal cartilage cDNA library. Sequence analysis of 420 cDNA clones identified 210 clones derived from established genes but, for many of them, expression in cartilage had not been previously reported. Among the established genes were 14 genes known to produce skeletal abnormalities in either humans or mice when mutated. Thirty-two uncharacterized genes and their respective chromosomal positions were also identified. To further understand the expression profile of these genes in fetal cartilage, we constructed a cDNA microarray utilizing the clones. The microarray was used to determine which genes had higher expression in cartilage as compared with dedifferentiated, cultured chondrocytes. Many of the established genes, as well as five of the uncharacterized genes, had increased expression in cartilage, suggesting an important role for these genes in the differentiated state of chondrocytes. These data provide new candidate genes for the osteochondrodysplasias and demonstrate the usefulness of cartilage cDNA microarrays in expanding our understanding of the complexity of fetal cartilage gene expression.