Fig. 8. Quantification of MT1-MMP and MMP-2 mRNA expression by RPA. (a) There was little to no detectable protected MT1-MMP mRNA in the 1- or 9-day-old Egfr^-/- lungs, while protected mRNA fragments were detected in the control littermate. (b) By contrast, MMP-2 mRNA was protected from degradation using the MMP-2 RNA probe with RNA from wild-type and Egfr^-/- mice. (c) Egf regulates MT1-MMP expression in lung fibroblasts. Fibroblasts were isolated from E12 lungs produced by mating of Egfr^+/- mice. Egfr^-/- and wild-type lung fibroblasts were deprived of serum factors overnight, followed by stimulation with 100 ng of murine Egf or Fgf-2 for 16 hours. Total RNA was then isolated and used for quantification of MT1-MMP mRNA by RPA. Major protected bands were quantified and the amount of increase over baseline are as shown.