Expression of a cellular oncogene during liver regeneration.

The number of transcripts of the cellular oncogene ras, which is homologous to the transforming gene of Harvey sarcoma virus, increases during liver regeneration in rats. The increase in these transcripts in liver polysomal polyadenylated RNA occurs at the time of activation of DNA synthesis during the regenerative process induced by partial hepatectomy or carbon tetrachloride injury. The number of ras transcripts returns to basal levels within 72 hours. These observations show that transcription of a cellular oncogene increases in a regulated way in a nonneoplastic growth process.