Abstract
RNA interference (RNAi) provides a powerful method for gene silencing in eukaryotic cells. We report on an RNAi technique-induced Pit-1 gene silencing in a GH-secreting cell line MtT/S using duplexes of 21-nt RNAs. By immunocytochemical analysis, the decrease in Pit-1 immunoreactivity was observed in a fraction of siRNA transfected MtT/S cells, while actin and tubulin showed no change in expression following transfection. Moreover, the double staining of Pit-1 and GH indicated that GH production was reduced only in MtT/S cells in which Pit-1 immunoreactivity was decreased by transfection. These results suggested that functional specific knock-down of Pit-1 was induced by transfection of siRNA. Together with the defects of somatotropic lineage and hypoplastic phenotypes in Snell dwarf mice and the transfection experiments using Pit-1 antisense oligonucleotides, our experiments support the theory that Pit-1 plays a crucial role in GH gene expression in individual cells.
