cDNA-RDA of genes expressed in fetal and adult lungs identifies factors important in development and function

The identification of genetic factors important in lung development and fun ction will help in understanding the underlying molecular mechanisms of res piratory disease. Representational difference analysis of cDNA (cDNA-RDA) i s a PCR-based subtractive enrichment procedure for the isolation of differe ntially expressed genes. We performed cDNA-RDA and isolated genes expressed more abundantly in fetal and adult lungs. Fifty-four clones potentially re presenting genes with higher transcript levels in the fetal lung were seque nced. Sequence similarity searches indicated that these clones included 12 known genes, a discoidin-like domain-containing gene, six expressed sequenc e tags (ESTs), and one novel sequence. Fifty-six clones potentially represe nting genes expressed more abundantly in the adult lung were also cloned an d sequenced. Of these, 16 known human genes were represented along with two sequences significantly similar to known mouse genes and two novel sequenc es. Several of these known genes are implicated in stress response and lung protection. Thus cDNA-RDA was successfully used to isolate known and novel differentially expressed genes, which putatively play an important role in human lung development.