FIGURE 5.

Quantitative RT-PCR analysis of the splicing of U12-type introns in endogenous genes. Stable L-929 and 3T3-D1 cell lines transfected with either a vector or a U4atac overexpression plasmid were analyzed using primers described in Figure 4. All data were normalized against the U2-type exon signal that was set to 1.0, as described in Materials and Methods. The first four bars (“intron”) in each panel represent the signal either from the unspliced U2- or U12-type introns in the absence or presence of the U4atac overexpression plasmid, as indicated in the figure. The next four bars (“exon”) in each panel show the corresponding data for the spliced U2- and U12-type mRNAs. Note that the y-axis is discontinuous in the Drap1, Ipo4, Psmc4, Gars, and smE panels. Pex16 intron data for L-929 cells has been included as a scaled-up inset because of large differences between the 3T3-D1 and L-929 data. Error bars indicate standard deviation.