FIG. 3.

Template requirements for TNTase activity. RdRp and TNTase assays performed with HΔ21. The nucleotide substrates used are shown above the autoradiogram. Asterisk (∗) identifies the radiolabeled nucleotide. r3 denotes the presence of GTP, ATP, and UTP in the reactions. The lengths of the reaction products (in nucleotides) are indicated on the side of the autoradiogram. (A) Reactions performed with RNA LE19 are in lanes 1 and 2, while those performed with the puromycin-modified LE19P are in lanes 3 to 6. (B) Comparison of TNTase activity performed with HΔ21, [α-³²P]rCTP, and either an RNA or DNA version of LE19. (C) Autoradiogram of the products from TNTase (lanes 1 and 2) and RNA synthesis (lanes 3 and 4) reactions, untreated (U) or treated with RNase T₁ (T1).