Figure 5.

Mass spectra for the detection of C→T variation. Transcriptional sequencing reactions were carried out with intact T7 RNA polymerase using UTPαS instead of UTP. The templates were derivatives of the previously described plasmid pKJ02 (21) containing a T7 promoter. The TTT sequence at the +16 to +18 positions of pKJ02 was changed to CCC and CTC, and the two resulting templates are different only at the +17 position. Only C-specific reactions analyzed by MALDI-TOF MS are shown. The top (N) and middle (M) spectra show the +17C- and +17T-carrying samples, respectively, and the bottom (H) shows a 1:1 mixture of the two samples.