FIGURE 5.

Mutant and wild-type Mtr4p complexes possess robust polyadenylation activity in vitro. Polyadenylation of radiolabeled synthetic initiator tRNA was conducted with purified complexes containing wild-type Mtr4p (MTR4), Mtr4–20p (mtr4-20), or proteins purified from an extract containing no TAP-tag (Mock). Reactions were incubated from 0 to 90 min with (1 mM) or without ATP at 30°C and once stopped by addition of formamide loading dye separated by denaturing polyacrylamide electrophoresis, dried, and detected by autoradiography. (Lane 1) A control reaction with no protein added.