FIG. 6.

Reconstitution of P3 base pairing potential in trans restores repeat addition processivity and hTR dimerization to a P3 mutant. (A) Recombinant telomerases were reconstituted in the presence or absence of hTR170, and elongation products were examined using the direct primer extension assay. Repeat addition processivity (R.A.P.) and first telomere repeat DNA synthesis (DNA synth.) values were expressed as percentages of the corresponding values for wild-type (WT) enzyme and are indicated below the gel. n/a, not applicable. (B and C) In vitro dimerization of hTR mixtures. (B) Percent dimer yield for mixtures of hTR mutants was calculated by measuring the combined homo- and heterodimer signal, which was expressed as a percentage of the total signal for monomers and dimers. Mean dimerization values that were significantly different (P < 0.01) from the wild-type (WT) hTR value are indicated by two asterisks. (C) Representative dimerization results. The positions of monomers (one asterisk) and homo- and heterodimers (which comigrated extensively) (collectively identified by two asterisks) are indicated to the right of the gel. DNA Marker V (Roche) was used as a size indicator.