RNA interference-mediated suppression of Creb and c-Fos expression on Aanat, Creb and c-Fos mRNA levels. Retinal cells were transfected with 50 ng of Creb siRNA, c-Fos siRNA, or lacZ siRNA, and incubated for 24 hours before harvesting for total RNA extraction; forskolin (10μM) was added for the last 6 h. Creb, c-Fos, and Aanat levels were expressed relative to Hprt mRNA with the value of the mock-transfected control set to 1. Values are presented as mean ± SEM; n=5. A. Transfection of siRNA complementary to Creb mRNA led to a significant decrease of Creb (**p<0.001 vs. control). B. Transfection of siRNAs complementary to c-Fos mRNA or Creb mRNA significantly decreased c-Fos transcript level (#p=0.005, *p<0.05). C. Transfection of siRNAs complementary to c-Fos mRNA or Creb mRNA significantly decreased Aanat transcript level (**p<0.001). For further details see Materials and Methods.