Fig 5. Affinity purification of cDNAs primed with biotinylated RT primers circumvents nonspecific priming during RT.

(A and B) RNA extracted from a high titer stock of cell-free LCMV virions was subjected to standard RT-PCR to detect S segment vRNA using the RT primer S 2865- and PCR primers 1856+ and 2628- (note that the sequence for primer 1856+ is listed in the Methods). In panel (A), three RT conditions were tested. The first RT condition featured a standard RT primer, the second had a biotinylated primer, and the third had no RT primer, as indicated. A portion of each reaction was subjected to affinity purification using streptavidin magnetic beads and then both the input and streptavidin-purified cDNAs were subjected to PCR. In panel (B), two RT conditions were tested: one with a biotinylated RT primer and the other without an RT primer. In an attempt to eliminate nonbiotinylated cDNAs from nonspecifically binding to streptavidin beads, a panel of four wash buffers (the 2X wash buffer from the Dynabeads kilobaseBINDER Kit, a 1X dilution of this buffer alone or containing 0.5% Tween 20, or water containing 0.5% Tween 20) were used during affinity purification. Following affinity purification, the captured cDNAs were subjected to PCR.