Human telomerase reverse transcriptase binds to a pre-organized hTR in vivo exposing its template

Area of Science:

• Molecular Biology
• Biochemistry
• Cell Biology

Background:

• Telomerase is essential for maintaining telomere length.
• Human telomerase comprises telomerase RNA (hTR) and telomerase reverse transcriptase (hTERT).
• Understanding the structural dynamics of hTR and its interaction with hTERT is critical.

Purpose of the Study:

• To investigate the in vivo structure of hTR.
• To determine hTERT-induced conformational changes in hTR within living cells.
• To elucidate the role of hTR structure in hTERT interaction.

Main Methods:

• In vivo dimethyl-sulfate (DMS) chemical probing.
• Analysis of hTR structure and accessibility.
• Assessment of hTR conformation with and without hTERT.

Main Results:

• The pseudoknot and triple helical scaffold of hTR form stably in vivo, independent of hTERT.
• hTR alone can adopt a conformation suitable for hTERT interaction.
• The template region of hTR shows limited accessibility without hTERT but becomes exposed upon hTERT binding.

Conclusions:

• hTR possesses a stable intrinsic structure that can pre-organize for hTERT binding.
• hTERT binding significantly alters hTR conformation, primarily by exposing the template region.
• These findings provide insights into the mechanism of human telomerase assembly and function.