Total RNA isolated from primary chondrocytes or ACVs was reverse transcribed using random hexamers for priming, and RT reactions were subjected to PCR with primers to the indicated genes. RT-PCR products were then resolved on an agarose gel. Water was used as a negative control. For each gene set, lane M contains size markers (100-, 600-, and 1500-bp bands are indicated), lane 1 contains RT-PCR products from chondrocyte RNA, lane 2 contains RT-PCR products from ACVs, and lane 3 shows the products of a PCR reaction using water.