FIG. 4.

Examination of nontemplated nucleotide addition to the template RNA. The names of the proteins used and the most relevant conditions are indicated above the appropriate lanes in the autoradiogram. The term rC*r3 means that the reaction contains all four nucleotides, with CTP being the radiolabel. rC* denotes a reaction performed with only [α-³²P]CTP. The lengths of the products, in nucleotides, are indicated to the left of the autoradiogram. All of the lanes within a panel are from one experiment, but some lanes are juxtaposed to facilitate presentation of the results.