Figure 4.

MKK7 intronic sequences are required for activation-induced skipping of exon 2 and recruit RNA-binding proteins. (A) Schematic of MK7 minigenes. MKK7 sequences are orange, and β-globin sequences are gray. (B) Graph of average fold repression (ratio of included to skipped isoforms in stimulated over unstimulated conditions) as determined by RT–PCR of MKK7 minigenes with minigene-specific primers. (C) UV cross-linking with nuclear extracts from Jurkat T cells (±PMA, 60 h) to radiolabeled in vitro transcribed MKK7 RNAs followed by RNase digestion and resolution on an SDS-PAGE. Note that the +PMA sample for the MKK7 construct was run on the same gel as the −PMA sample but with a spacer lane that has been removed. (D) Immunoprecipitation of UV cross-linking reactions of the intron constructs in C after RNase digestion with the antibodies shown.