TABLE 1.

The effect of reporter mRNA abundance on PRF efficiency

Strain	Reportera	β-Gal activityb	LacZ mRNA abundancec	Corrected β-Gald	% PRF correctede
Wild type	Control	14.24 (± 1.14)	1.88	7.57 (± 0.60)
Wild type	L-A	0.28 (± 0.04)	0.88	0.31 (± 0.05)	4.14 (± 0.74)
upf1Δ	Control	15.88 (± 0.94)	2.54	6.25 (± 0.37)
upf1Δ	L-A	1.14 (± 0.08)	2.80	0.41 (± 0.05)	6.52 (± 0.90)

^alacZ monocistronic reporter plasmids. Control: lacZ in-frame with AUG. L-A: contains L-A derived -1 PRF signal, lacZ in -1 frame with AUG.

^bβ-Galacosidase assays were performed in triplicate on at least three separate occasions.

^cAverage LacZ mRNA abundance calculated as the ratio of LacZ to 5S rRNA signal from two independent experiments.

^dβ-Galacosidase activities were divided by the average LacZ mRNA abundance in each strain.

^e% PRF = (corrected β-Gal L-A/corrected β-Gal control) ·100%.