FIGURE 2.

Effect of the ATP:UTP ratio on UTP-dependent RNA turnover. Mitochondrial vesicles were labeled with [α-³²P]CTP and subsequently incubated in transcription buffer containing 2 mM CTP (-UTP); 2 mM CTP and 2 mM UTP (+UTP); 2 mM CTP and 2 mM ATP (ATP); or 2 mM CTP, 2 mM UTP, and either 1 mM ATP (0.5 A:U); 2 mM ATP (A:U); 4 mM ATP (2A:U); 8 mM ATP (4A:U); or 8 mM GTP (4G:U). After 15 min, incorporation of [α-³²P]CTP into polyadenylated RNAs was measured. Percent polyadenylated RNA remaining as compared to pulse-labeled RNA (X) is plotted. Each point is the average of three experiments, and the error bars represent one standard deviation.