Figure 2

cDNA synthesis by mini-Tnt1. (A) Schematics of mini-Tnt1 constructs that were introduced into tobacco protoplasts. LTR sequences are shown as boxes with solid triangles. The thin red lines denote locations of the PBS and PPT. The artificial intron (AI) is depicted by a small black box. Kanamycin-resistant (Kan^r) calli were obtained for each construct and scored by PCR for the loss of the intron in NPTII. Percentage intron loss is the number of Kan^r calli with complementary (c)DNA (as measured by the absence of the intron) divided by the total number of calli scored, multiplied by 100. Exact numbers of events scored are indicated in parentheses below the percentages. (B) Typical results of the PCR screen for intron loss among Kan^r calli. Lane 1 = molecular length markers; lane 2 = PCR results using a control template that has the intron; lane 3 = PCR results using a control template without an intron; lanes 4-10 = PCR results from DNA samples derived from individual Kan^r calli.