Figure 5.

Nucleolar function of F10 and BL6 cells. A: In vitro RNA synthetic activity. Nuclei were purified from F10 and BL6 cells, and examined for RNA synthetic activity. The amount of [³H]UTP incorporated into already initiated and elongating transcripts was measured in the absence (−) or presence (+) of α-amanitin. The data represent the mean ± SD of two experiments. *, P < 0.01 by t-test when compared with the value of F10 cells in each assay condition. B: Evaluation of the translational efficiency of the exogenous Luc gene. F10 and BL6 cells were transfected with the pRL-CMV, pRL-SV40, or pRL-actin. F10 cells were also transfected with pcDNA3 or pcDNA3-Sik-SP together with the pRL-CMV, pRL-SV40, or pRL-actin. After the cells were cultured for 24 hours, they were examined for Luc gene dosage (Southern), and Luc activity (bar graph). Relative Luc activity was calculated as described in the Materials and Methods. *, P < 0.01 by t-test when compared with the values of F10 and pcDNA3-co-transfected F10 cells in each Luc construct.