FIGURE 3.

Effect of intron inclusion on the expression of indicator genes in four cell lines. 293T, HeLa, NIH3T3, and quail QCl-3 cells were transfected with 200 ng each of a matched intron⁺ or intron⁻ plasmid encoding CAT, β-gal, luc, or SEAP. Cells were also transfected with pCMV/β-gal or pCMV/CAT as an internal control. The fold increase seen upon intron inclusion is indicated, after correction for the internal control. An average of three experiments with SD is indicated.