Figure 4.

(A) Activity and processivity of human telomerase mutants by a modified TRAP assay. Lane 1, 1× CHAPS control; lane 2, RRL without hTR; lane 3, recombinant telomerase activity reconstituted from wild-type hTR; lanes 4–13, recombinant telomerase activity reconstituted from variant telomerase RNAs, Δ1–Δ5 and Sub1–Sub5. For the standard assay conditions see Materials and Methods. The product bands selected for quantitative processivity analysis (Materials and Methods) are indicated by arrows. (B) Processivity of wild-type and mutants telomerases. P₁ represents the processivity of wild-type and mutated telomerases at the first visible telomeric repeat; P₂ is the processivity at the second repeat and so forth. See Materials and Methods for a description of quantitation and calculations performed. Reactions were performed in duplicate and the average processivity and standard deviation for each position were determined and plotted alongside the wild-type values.