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A molecular switch underlies a human telomerase disease
Luis R Comolli1, Ivan Smirnov, Lifeng Xu
1Departments of Pharmaceutical Chemistry and Biochemistry and Biophysics, University of California, 513 Parnassus Avenue, San Francisco, CA 94143, USA.
Summary
Telomerase RNA pseudoknot mutations cause disease by disrupting its two-state molecular switch function, impacting telomere maintenance and cellular health.
Area of Science:
- Molecular Biology
- Biochemistry
- Genetics
Background:
- Telomerase is essential for telomere maintenance and is linked to cancer.
- Mutations in the telomerase RNA gene cause diseases like dyskeratosis congenita and aplastic anemia.
- These mutations affect a conserved telomerase RNA pseudoknot structure.
Purpose of the Study:
- To investigate the functional, structural, and energetic properties of the telomerase RNA pseudoknot.
- To understand how mutations in the pseudoknot affect telomerase activity.
- To explore the role of the pseudoknot as a molecular switch.
Main Methods:
- In vitro telomerase assays
- Nuclear Magnetic Resonance (NMR) spectroscopy
- UV absorbance melting analyses of model oligonucleotides
- Phylogenetic covariation analysis
Main Results:
- The telomerase RNA pseudoknot exists in two alternative, equally stable states in solution.
- A disease-associated mutation (GC1078 --> AG) abrogates telomerase activity by stabilizing an alternative structure.
- Hyperstabilizing the pseudoknot pairing also decreases telomerase activity.
- Phylogenetic analysis supports the existence of a functional molecular switch.
Conclusions:
- The P2bP3 pseudoknot domain functions as a molecular switch, with interconversion between its two states crucial for telomerase activity.
- Dysfunctional pseudoknot switching due to mutations can lead to impaired telomere maintenance and associated diseases.
- Understanding this molecular switch offers insights into telomere biology and potential therapeutic targets.