# Investigating telomerase dynamics in live cells at a single-molecule level

> **NIH NIH R01** · SLOAN-KETTERING INST CAN RESEARCH · 2024 · $404,237

## Abstract

Abstract:
 Eukaryotic cells solve the end-replication and end-protection problems through the addition
of telomere sequences to the ends of chromosomes. Proper regulation of telomere length is
critical for genome integrity, regulation of cellular lifespan, aging, and cancer. Over the years,
genetic and biochemical studies have shed an enormous amount of light on how this process is
controlled. However, the cell biology of this process in the crowded nucleus remains poorly
understood, and the timing, dynamics, and spatial coordination of telomere extension are
unknown. To address these gaps in our understanding, we will exploit the MS2 tagging system
and Halo-fluorophore to visualize single molecules of endogenous telomerase in live cells. Here,
we will decipher discrete and critical steps as hTR traffics from Cajal bodies to telomeres.
Contrary to earlier FISH data in fixed cells, our preliminary data using diffraction-limited and
super-resolution imaging modalities combined with single-molecule FISH show that hTR is
broadly distributed throughout the nucleus. At telomeres, we show that following TPP1-driven
recruitment, stable interactions are established between the enzyme and its substrate by
RNA:DNA base pairing. Our goal is to apply photoactivation and photobleaching experiments to
test the role of the catalytic subunit, hTERT, in the gating of hTR between the Cajal bodies and
telomeres. In addition, we will engineer a short telomere to depict telomerase dynamics at
critical telomeres that need to be elongated. Lastly, we will perform a proximity-based labeling
and purification methodology to investigate the factors that control key steps of telomerase
trafficking to short telomeres. All in all, our innovative approach offers a detailed view of the
precise mechanics of telomere extension at physiological timescales and opens many future
avenues for the study of the link between telomere maintenance and aging as well as cancer.

## Key facts

- **NIH application ID:** 10918228
- **Project number:** 5R01GM150229-02
- **Recipient organization:** SLOAN-KETTERING INST CAN RESEARCH
- **Principal Investigator:** Pascal Chartrand
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $404,237
- **Award type:** 5
- **Project period:** 2023-09-01 → 2027-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10918228

## Citation

> US National Institutes of Health, RePORTER application 10918228, Investigating telomerase dynamics in live cells at a single-molecule level (5R01GM150229-02). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10918228. Licensed CC0.

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