Figure 4.

CUP represses an mRNA reporter containing the oskar 3′ UTR. (A–D) S2 cells were transfected with a mixture of three plasmids: one expressing the F-Luc-oskar reporter, another expressing the Renilla luciferase (R-Luc) as a transfection control, and a third expressing GFP or CUP. Additionally, transfection mixtures contained a plasmid expressing GST or Bruno as indicated. (A) Firefly luciferase activity was normalized to Renilla luciferase and set to 100 in control cells (i.e., expressing GFP and GST). (B) F-Luc-oskar mRNA levels were normalized to those of the Renilla mRNA and set to 100 in control cells. Mean values ± standard deviations from three independent experiments are shown. (C) F-Luc activity was normalized to the mRNA levels. (D) Northern blot analysis of RNA samples corresponding to those shown in B. (E–H) S2 cells were transfected with a mixture of three plasmids: one expressing the F-Luc-oskar reporter, another expressing the Renilla luciferase (R-Luc) as a transfection control, and a third expressing MBP or CUP. Additionally, all transfection mixtures contained a plasmid expressing Bruno. Luciferase activity and mRNA levels were analyzed as described in A–D.