<span>The metabolic activity of a specific region of the living rat brain can be revealed by measurement of Fos protein concentration.
c-Fos is a proto-oncogene that is the homolog of the retroviral oncogene v-fos. It was first discovered in rat fibroblasts as the transforming gene of the FBJ MSV.</span>
D.by causing a change in the protein that forms during translation
