Cloning oncogenic ras-regulated genes by differential display.

The coordinated regulation of gene expression is a key cellular function that specifies cell characteristics as well as controls normal physiological processes of the organism. Deregulation of this gene expression leads to a variety of abnormal conditions such as cancer. The ras oncogene is one of the most frequently found mutations in various types of human cancer. The mutated Ras protein constitutively elicits multiple mitogenic signals to the nucleus to alter gene expression of target genes that are involved in a broad range of normal cellular functions. Thus the identification of these genes may provide an important tool toward the understanding of these pathogenic processes. As a first step to reveal these processes at the molecular level and to dissect the key pathway employed by oncogenic Ras protein, we have looked for its target genes in rodent model cell lines using the differential display method. Our initial screening has isolated a number of genes either up- or downregulated by oncogenic ras activation. Although the functional analyses of these genes in terms of ras-mediated cell transformation will be the major challenge, differential display has come to be a very efficient tool that helped us move to the next step. In this short report, we focus primarily on the technical aspects of differential display and experimental designs used in this study.