FIGURE 8.
A subclass of SR proteins activate exon 9A9′ splicing through UTE. The wild-type (WT) or ΔUTE mutant constructions were injected into the nucleus of stage VI oocyte alone or in presence of in vitro transcribed RNA encoding V5-tagged SR proteins. A, V5-tagged SR protein expression in cytoplasmic and nuclear fractions was monitored by Western blotting using a V5 antibody. B, total RNA was subjected to 3′-RACE-PCR using a 32P-oligonucleotide specific to the SV40 minigene reporter. The structure of the amplified fragments is indicated on the right. Quantification was performed on a PhosphorImager to yield the proportion of each mRNA given in the table below. ND, not detected.