PT  - JOURNAL ARTICLE
AU  - Eric M. Patrick
AU  - Joseph Slivka
AU  - Bramyn Payne
AU  - Matthew J. Comstock
AU  - Jens C. Schmidt
TI  - Mechanism of processive telomerase catalysis revealed by high-resolution optical tweezers
AID  - 10.1101/700294
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 700294
4099  - http://biorxiv.org/content/early/2019/08/23/700294.short
4100  - http://biorxiv.org/content/early/2019/08/23/700294.full
AB  - Telomere maintenance by telomerase is essential for continuous proliferation of human cells and is vital for the survival of stem cells and 90% of cancer cells. To compensate for telomeric DNA lost during DNA replication, telomerase processively adds GGTTAG repeats to chromosome ends by copying the template region within its RNA subunit. Between repeat additions, the RNA template must be recycled. How telomerase remains associated with substrate DNA during this critical translocation step remains unknown. Using a newly developed single-molecule telomerase activity assay utilizing high-resolution optical tweezers, we demonstrate that stable substrate DNA binding at an anchor site within telomerase facilitates the processive synthesis of telomeric repeats. After release of multiple telomeric repeats from telomerase, we observed folding of product DNA into G-quadruplex structures. Our results provide detailed mechanistic insights into telomerase catalysis, a process of critical importance in aging and cancer.