Rapid identification of a novel chondrocyte-specific gene by RNA differential display

Differential display or RNA fingerprinting is a novel approach for the isolation of differentially expressed genes. Here we describe the application of the RNA differential display technique to the analysis of the genes expressed in chick embryonic sternal chondrocytes, fibroblasts and BrdU-treated chondrocytes, which dedifferentiate back to mesenchymal-like phenotype. Parallel display among the genetags allowed us to isolate seven clones with differential expression patterns. Nucleotide sequencing of one of these clones revealed that it is a novel developmentally regulated gene with no significant homology to those reported previously. An RT-PCR analysis, using primers derived from this novel clone, confirmed the presence of the corresponding RNA only in the untreated chondrocytes, and not in the BrdU-treated chondrocytes or fibroblasts. This confirmation of the expression pattern given by the differential display reinforces the reliability of this approach. These results indicate that the differential display analysis provides a rapid and effective way to identify novel differentially expressed genes during chondrogenesis.