Dose effect of antisense PNA on LacZ protein activity and lacZ mRNA abundance. AS19 cells induced with 100 μM IPTG and treated with increasing concentrations of anti-lacZ PNA were harvested at ΔOD550 < 0.1 for LacZ activity and RT-PCR measurements. (A) Relative amounts of LacZ protein (hatched bars) and lacZ mRNA (slashed bars) are shown as mean values from three separate experiments +/- std. Nontreated samples were used as standard and un-induced samples were used to remove background. (B) Nonlinear correlation between LacZ activity and mRNA abundance after treatment with anti-lacZ PNA at increasing concentrations. The average values shown in panel (A) were plotted following log transformation of the LacZ activity data. Linear regression analysis of the plotted data indicates R = 0.974 for the correlation with the two tailed p < 0.001.