Specific stimulation of actin gene transcription by epidermal growth factor and cycloheximide.
Stimulation of quiescent AKR-2B mouse embryo cells with epidermal growth factor (EGF) results in a rapid and specific induction of actin mRNA sequences. These mRNAs include those coding for both beta- and gamma-cytoskeletal, but not alpha-skeletal muscle, actin isotypes. Elongation of nascent RNA chains in isolated nuclei (run-off transcription) demonstrates that the mRNA accumulation is preceded by an increase in actin gene transcription. This increase is transient, however, and is followed by a rapid attenuation of transcriptional activity. An inhibitor of protein synthesis, cycloheximide, was also found to induce beta- and gamma-actin mRNA accumulation. Furthermore, the simultaneous addition of EGF and cycloheximide produced a synergistic effect on actin sequences in both steady-state nuclear and polysomal RNA. Run-off transcription experiments demonstrate that this synergistic effect results from an increase in the magnitude and duration of actin gene transcription. It is also specific in that alpha-tubulin gene transcription is not similarly affected. These data suggest the existence of a specific labile repressor of actin gene transcription.
D000199:Actins / Q000235:genetics*; D000818:Animals; D002460:Cell Line; D003513:Cycloheximide / Q000494:pharmacology*; D004622:Embryo, Mammalian; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D005796:Genes / Q000187:drug effects*; D051379:Mice; D008806:Mice, Inbred AKR; D012333:RNA, Messenger / Q000235:genetics / Q000302:isolation & purification; D014158:Transcription, Genetic / Q000187:drug effects*
D000199:Actins; D012333:RNA, Messenger; D004815:Epidermal Growth Factor; D003513:Cycloheximide