Fig. 5. MMP-9 promoter activation by RasV12 is MEK/ERK-dependent but 3ß1-independent. (A) MMP-9 promoter activity: MK^+/+ cells (+/+), MK^–/– cells (–/–) and MK^–/– cells expressing human 3 (3) were grown on LN-5 ECM and transfected with an MMP-9 promoter/luciferase reporter plasmid. 24 hours later, cells were assayed for luciferase expression as described in the text. Normalized luciferase signals are plotted as the percentage of control levels seen in MK^+/+ cells. Data are presented as the mean±s.e.m.; n=3 in two separate experiments. (B) MK^+/+ cells (MK+/+), MK^–/– cells (MK–/–), or MK^–/– cells transfected with 3 (3) grown on LN-5 ECM were infected with adenovirus expressing either HA-tagged RasV12 (Ras) or ß-galactosidase (C); MOI=10. Cells were then transfected with the MMP-9 promoter/luciferase reporter plasmid in the presence or absence of 10 µM U0126, as indicated and assayed for luciferase expression as in A. Normalized luciferase signals are plotted relative to the control levels seen in the absence of U0126, which is set to 1.0 for each cell type (C, –). Data are presented as the mean±s.e.m.; n=3 in two separate experiments.