Transcription of protooncogenes during stimulation of normal human B lymphocytes.

Protooncogenes play important roles in the regulation of growth and differentiation of normal cells. In this study we have examined the cell cycle-dependent regulation of transcription of various protooncogenes after stimulation of human peripheral blood B lymphocytes. The transcriptional rate of various genes was determined by means of a nuclear run-on assay. We found that several protooncogenes were transcriptionally activated after stimulation (myc, p53, K-ras, H-ras, sis and ets), but with different kinetics of induction. In contrast, some oncogenes, especially those encoding membrane-associated or cytoplasmatic proteins like abl, rel or mil/raf, were transcribed at a relatively constant rate during the cell cycle.