Since many lines of evidence suggest that expression of the transforming growth factor-β1 (TGF-β1) gene may be regulated post-transcriptionally, we examined the effect of the 5'-untranslated region (UTR) of this gene on TGF- β1 expression. For this purpose, fragments of the 840-nucleotide highly GC- rich TGF-β1 5'-UTR were inserted into the 5'-UTR of the structural gene for human growth hormone driven by the simian virus 40 early promoter. A portion of the 5'-UTR of TGF-β1 mRNA spanning the sequences from +11 to +147 was shown to inhibit growth hormone expression by as much as 22-fold. This effect was cell-specific; growth hormone production was inhibited in PC-3 human prostate adenocarcinoma and A-549 human lung adenocarcinoma cells, while no effect was seen in rat pheochromocytoma PC12 cells, which show efficient translation of endogenous TGF-β1 mRNA. Computer analysis showed that this region of the 5'-UTR contained a stable secondary stem-loop structure spanning sequences +49 to +76. This stem-loop region alone is sufficient to inhibit expression of the growth hormone gene, suggesting that it plays an important role in post-transcriptional regulation of TGF-β1 gene expression.
|Original language||English (US)|
|Number of pages||6|
|Journal||Journal of Biological Chemistry|
|State||Published - 1992|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology