HnRNP LL functionally contributes to repression of CD45 exon 4. (A) Schematic of the WT ESS1 exon 4 minigene described previously (Melton et al. 2007) used in Figures 5 and 6. (B) RT–PCR of WT minigene expression following transient cotransfection in JSL1 cells with constructs expressing Flag-hnRNP L, Flag-hnRNP LL, or Flag vector alone. Percent exon 4 skipping is calculated from two to three independent experiments. Standard error in each case is <15% of exon-skipped value. (*) Cryptic product observed variably with reduced cell viability. (C) Total protein extracts from transfections in B blotted for Flag, hnRNP LL, or hnRNP L. (*) The band corresponding to hnRNP LL, lower band is a nonspecific signal observed on occasional blots. (D) RT–PCR of WT minigene expression following transient cotransfection with morpholino oligomers (MO) that block translation of hnRNP L or LL. Percent exon 4 skipping is calculated as in B. (E) Total protein extracts from transfections in D blotted for hnRNP L or LL. (*) The band corresponding to hnRNP LL.
