Fig. 1.

Purified Est1 enhances telomerase DNA extension activity in vitro. (A) Recombinant Est1 (1 μg) was resolved on a 12% SDS/PAGE and stained with Coomassie Blue. (B) The Est1 effect on telomerase-mediated DNA extension was tested using extracts prepared from est1Δ yeast with an immobilized 7-base 3′-overhang DNA substrate. The DNA extension reactions were supplemented with BSA or Est1 (1, 2.5, 5, 10, 25, and 50 nM), as marked. To serve as a loading control an end-labeled 27-base primer was added before precipitation of the extension products. The positions of the loading control primer and + 1 extension product are marked.