we tested the hypothesis that the mitogenic effect of estrogen occurs via activation of the expression of cellular proto-oncogenes by measuring the rate of transcription of 20 proto-oncogenes ( abl , bas , erb-a , erb-b , ets , fms , fos , fps/fes , mos , myb , myc , n-myc , raf , ha-ras , ki-ras , n-ras , rel , sis , src , and b-lym ) in the uterus of ovariectomized rats before and after injection of estrogen . c-onc transcriptional activity was monitored both by an in vitro transcription assay on isolated nuclei ( run-on ) and by analysis of mature mrna . c-fos and c-myc proto-oncogenes were found to respond to estrogen with increased expression : c-fos within 30 min , with a first , sharp peak at 2 h and c-myc within 1.5 h , with a first , broad peak at 4-6 h .
C0007634
cellular
C0007610
nuclei