Fig. 7. A JNK inhibitor blocks WNT3a-stimulated LEF/TCF-sensitive transcription. (A,B) F9 cells stably expressing rFZ1 and pTOPFLASH luciferase reporter were transfected with dominant-negative (DN) versions of either RhoA, Rac1 or Cdc42 (A) and either DN-MEKK 1 or DN-MEKK 4 (B) for 24 hours, followed by overnight serum starvation. The cells then were treated with or without WNT3a for 7 hours and luciferase gene reporter assays were performed. (C) Confluent F9 cells stably expressing rFZ1 and pTOPFLASH luciferase reporter were serum-starved overnight and treated with JNK (SP600125, 0.4 µM) or p38 (SB203580, 6 µM) inhibitors for 1 hour, followed by treatment with or without WNT3a for 7 hours. Lysates were collected and a luciferase assay was performed, as described in the Materials and Methods. The data represent mean values±s.e.m. from a single experiment performed in triplicate and are representative of three separate experiments whose results were in strong agreement. **P<0.01; versus –WNT3a control; ^#, P<0.05; ^##, P<0.01 versus +WNT3a control.