Elevation of the thyroid hormone receptor erb A-alpha 2 mRNA in transformed rodent cells is due to increased message stability.

Abstract

Previously, the authors reported an elevation of erb A-alpha 2 mRNAs in transformed rodent cells when compared with their non-transformed counterparts (Cancer Res., 52(1992) 2186-2190). To investigate this phenomenon further the rates of gene transcription and the effects of translation/transcription inhibition on erb A-alpha 2 mRNA expression were examined. The present study found no difference between non-transformed and transformed cells in erb A-alpha 2 gene transcription rate, nor an effect of cycloheximide on erb A-alpha 2 mRNA expression. However, a significant difference was obtained with actinomycin D. With this inhibitor, the half-life of erb A-alpha 2 mRNAs in nontransformed rodent cells was determined to be approximately 8 h. In contrast, the alpha 2 transcripts in their transformed counterparts showed no decay during this period, suggesting that the elevation of erb A-alpha 2 mRNAs in transformed rodent cells was due to increased transcript stability.