Effects of Tip110 mutants on pre-mRNA splicing-dependent CAT reporter gene expression. 293T cells were transfected with DM138 (lane 1), DM138 and Rev (lane 2), or DM138, Rev, and Tip110 (lane 3), Tip10 siRNA (lane 4), Tip110s (lane 5), ΔNLS (lane 6), ΔRRM (lane 7), or ΔLSM (lane 8). The cells were harvested 48 h after transfection for CAT assay (a) or Western blot for expression of Tip110 and its mutants (b). The amount of total DNA in all transfections was equalized with pcDNA3 plasmid. A CMVβGal plasmid was included to normalize the transfection variations for CAT assay, while β-actin was included to show equal loading.