FIGURE 4.

Isolation of proteins binding to a transcript containing the fibronectin EDA exonic splicing enhancer—EDA or a mutant version—EDAmt. (A) Sequences of EDA and EDAmt RNAs are shown. (B) Standard and (C) RNase-assisted RNA chromatography of EDA and EDAmt transcripts in HeLa nuclear extracts. Bands denoted A and B correspond to SF2/ASF and to hnRNP A2/B1, respectively, whereas bands C and D indicate FUBP1 and FUBP2, respectively. (Bottom) SF2/ASF Western blot analysis of the corresponding RNA chromatograms.