FIG. 4.

Nascent termination products of C102S and D90GR107C Pol III proteins have longer 3′ oligo(U) than C11-WT. (A) Schematic of the [³²P]RNA-DNA hybrid containing a dT₇ terminator. RNA is shown in boldface. (B) Transcription with four NTPs at 25°C using immobilized Pol III-C11-WT (lanes 1 to 4), Pol III-C102S (lanes 5 to 8), and Pol III-D90GR107C (lanes 9 to 12) for the times indicated below the lanes. Lanes 1, 5, and 9 show products using ATP and GTP only (before the addition of four NTPs), as in Fig. 3F. (C) Densitometric scans of the 28- to 38-nt regions of the 10-min time points reflect the distribution of RNAs produced as indicated. The arrow indicates the direction of transcription; the RNA sequence is indicated above, and corresponding template positions as numbered in panel A are below.