Figure 5.

JNK induces CELF2 protein expression, which drives activation-induced skipping of MKK7-E2. (A–D, top) Western blot showing mock-treated or knockdown of each MKK7 intron-binding protein left unstimulated or activated with PMA (48 h). n = 3. (Bottom) Graph of endogenous percent MKK7-E2 inclusion as determined by RT–PCR for the corresponding knockdown. (A) HuR knockdown. (B) SRp20 knockdown. (C) hnRNPC knockdown. (D) CELF2 knockdown. (E, top) RT–PCR analysis of MKK7 minigenes that were cotransfected with Flag-CELF2 in HEK293 cells. (Bottom) Corresponding Western blot for CELF2 overexpression. (F) Representative Western blot analysis of proteins that bind MKK7 introns in wild-type Jurkat cells or Jurkat cells depleted of JNK by shRNA grown under unstimulated conditions or activated with PMA (48 h). See also Supplemental Figure S5.