Real-time analysis of rhythmic gene expression in immortalized suprachiasmatic nucleus cells

Immortalized cells derived from the suprachiasmatic nucleus (SCN) retain many properties of the SCN including the capacity to generate circadian rhythms. Stably transfected SCN2.2 cells expressing the human c- promoter linked to a luciferase reporter gene ( /luc) were examined for evidence of transgene responses to stimuli known to induce c- expression and of endogenous rhythmic variation. Bioluminescence-reported transgene expression was induced in SCN2.2 /luc cells following stimulation with fetal bovine serum or KCl. SCN2.2 /luc cells showed 24 h rhythms of bioluminescence with a 9- to 19-fold difference between peak and minimum levels. These results demonstrate that the regulation of /luc transgene expression in SCN2.2 cells is similar to that of the endogenous c- gene in the SCN.