- Wan, Bingbing;
- Tang, Ting;
- Upton, Heather;
- Shuai, Jin;
- Zhou, Yuanzhe;
- Li, Song;
- Chen, Juan;
- Brunzelle, Joseph S;
- Zeng, Zhixiong;
- Collins, Kathleen;
- Wu, Jian;
- Lei, Ming
Tetrahymena telomerase holoenzyme subunits p75, p45 and p19 form a subcomplex (7-4-1) peripheral to the catalytic core. We report structures of p45 and p19 and reveal them as the Stn1 and Ten1 subunits of the CST complex, which stimulates telomerase complementary-strand synthesis. 7-4-1 binds telomeric single-stranded DNA, and mutant p19 overexpression causes telomere 3'-overhang elongation. We propose that telomerase-tethered Tetrahymena CST coordinates telomere G-strand and C-strand synthesis.