FIG. 6.

WW and FF domain-containing CA150 proteins can modulate exon selection. (A) The β-TM minigene was cotransfected with empty vector (mock) or different amounts (1, 2, or 4 μg) of HA-tagged CAΔN expression vector into 8 × 10⁵ HEK 293 cells. Splicing products were amplified by RT-PCR and analyzed by hybridization on blots using the SV40 probe as described previously (31). The SV40 probe cannot distinguish exon 6 or 7 inclusion; therefore, the upper band is labeled as 5-6/7-8-9. The Western blot was probed with anti-HA. (B) Transfection was as in panel A except that a variety of effector proteins as indicated above were tested. The blots were subjected to sequential hybridization with the SV40- and exon 6-specific probe (31), followed by quantitative analysis (bar graph). Averages and standard deviations reflect five independent experiments. (C) The E1A reporter was transfected with effector expression vector as indicated above the blot. The E1A mRNA products were detected by RT-PCR and hybridization (31).