Figure 4. Tailing efficiencies of DNA molecules with different lengths that share the same last seven bases.

(a) Tailing kinetics of four shorter molecules. Six FAM-labeled molecules with 70, 140, 280, 560, 840, and 1,120 bp sharing the same 7-bp 3′ sequence were prepared (see Supplementary Fig. S2) and 50 fmols of each (300 fmols in total) were mixed and incubated with MMLV-RT in the presence of dGTP. The reaction products were analyzed, and the size distribution of the tailing products of the four smaller molecules was determined. (b) dCMP stimulates tailing of the 280-bp DNA. In total, 100 fmols of the least efficient substrate DNA with 280 bp was subjected to G-tailing in the absence (left) or presence (right) of 2 mM dCMP. Results are shown as averages of triplicate experiments.