Rapid induction of the c-jun protooncogene in the avian oviduct by the antiestrogen tamoxifen

C. K. Lau, M. Subramaniam, K. Rasmussen, T. C. Spelsberg

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30 Scopus citations


This report describes a rapid regulation of the expression of the c-jun protooncogene by the antiestrogen tamoxifen (Tam). The c-jun protooncogene codes for an improtant component of the AP-1 transcription factor complex, which regulates the expression of many unlinked genes. Repeated experiments have shown that Tam rapidly increases the steady-state c-jun mRNA levels in the avian oviduct but decreases the levels in the liver. The Tam effects are time- and dose-dependent. These results are supported by other studies that have demonstrated that 17β-estradiol decreases steady-state levels of c-jun protooncogene mRNA in oviducts of animals fully withdrawn from estradiol. The effect of Tam in the avian oviduct is in contrast to the reported effects of Tam on the expression of practically all other genes in the avian oviduct and other animal tissues. Transcription analyses using nuclear runoff experiments with oviduct nuclei demonstrate a decreases in the c-jun gene transcription within minutes after Tam treatment with a return to 75% of control values by 4 hr. The that Tam transiently decreases the transcription of the c-jun gene but increases the steady-state c-jun mRNA levels suggest that Tam must alter both transcriptional and post-transcriptional events. The results support a role of the c-jun protooncogene as a regulatory gene in the cascade model for steriod action whereby steroids rapidly regulate the regulatory genes which in turn regulate many other structural genes.

Original languageEnglish (US)
Pages (from-to)829-833
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number3
StatePublished - 1991


  • Regulatory genes
  • Steroid action
  • Transcription analyses
  • mRNA levels

ASJC Scopus subject areas

  • General


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