Modulated cholecystokinin (CCK) mRNA expression is dependent on de novo protein synthesis

The human neuroblastoma cell line SK-N-MC expresses cholecystokinin (CCK) and c-fos mRNA. Levels of CCK and c-fos mRNA expression were studied by nuclear run-off transcription and Northern blot analysis. Addition of foetal calf serum or forskolin to the medium stimulated basal CCK and c-fos mRNA expression. Addition of cycloheximide suppressed the stimulation of CCK mRNA expression, whereas expression of c-fos mRNA was super-induced by the simultaneous addition of cycloheximide and forskolin or foetal calf serum. Western blot analysis revealed that c-fos mRNA is translated into Fos. Expression of c-fos in SK-N-MC cells suggests that Fos may be part of a functional transcription complex and that it may be involved in the regulation of basal and stimulated CCK mRNA expression in SK-N-MC cells.