TABLE 2.
Effects of RT mutations on the frequency of tandem repeat deletions
| Enzyme and [dCTP] (μM)a | No. of clones containing deletions of 8-10 nt/total no. of plaques analyzedb | fΔ[8-10nt]c |
|---|---|---|
| WT RT | ||
| 50 | 0/182 | <5.5 × 10−3 |
| 0.1 | 58/146 | 0.397 |
| M230L | ||
| 50 | 0/141 | <7.1 × 10−3 |
| 0.1 | 36/205 | 0.176 |
| M230I | ||
| 50 | 1/224 | 4.5 × 10−3 |
| 0.1 | 18/222 | 0.081 |
Nucleotide concentrations in the assays were either 50 μM each dNTP or 0.1 μM dCTP, 440 μM dTTP, 40 μM dATP, and 20 μM dGTP.
The number of clones harboring deletions of 8 to 10 nt in the target sequence and the total number of plaques were determined from two or three independent experiments. Blue and white plaques were both screened for deletions. The proportion of blue and white plaques analyzed was consistent with the data shown in Table 1. For example, in reactions carried out with the RT with M230I in the presence of a biased [dCTP]/[dTTP] ratio, we analyzed 80 blue plaques and 142 white plaques.
Deletion frequencies (fΔ[8-10nt]) were calculated as the ratio of the number of plaques containing a deletion of 8 to 10 nt to the total number of plaques analyzed. Deletions were identified by nucleotide sequencing. Frequencies obtained in different experiments were within a threefold range.