FIGURE 7.

SC35 activates the usage of exon 9A9′ as a 3′-terminal exon through UTE. A, the wild-type minigene driven by the SV40 early promoter was injected into the nucleus of stage VI oocytes into which in vitro transcribed V5-tagged xSC35 RNA (4, 8, and 16 ng) had been previously injected into cytoplasm. V5-tagged xSC35 expression was monitored by Western blotting using a V5 antibody. B, the wild-type (WT) and ΔUTE mutant minigenes were injected into the nucleus of stage VI oocytes into which in vitro transcribed V5-tagged xSC35 RNA had been previously injected into cytoplasm (+) or not (−). A and B, total RNA was subjected to 3′-RACE-PCR using a ³²P-oligonucleotide specific to the SV40 minigene reporter. Quantification was performed on a PhosphorImager to yield the proportion of each product given in the table below. MW, molecular weight markers.