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Updated: Feb 10, 2026
09:25
In vitro Reconstitution of the Active T. castaneum Telomerase
Published on: July 14, 2011
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La1: an evolutionarily conserved player in the Arabidopsis telomerase complex
Biorxiv : the Preprint Server for Biology
|February 9, 2026
Summary
Arabidopsis telomerase utilizes the RNA-binding factor AtLa1, essential for its function. This protein interacts with telomerase RNA (AtTR) and may compete with or sequentially bind to AtTR with AtNAP57 during biogenesis.
Area of Science:
- Plant molecular biology
- Telomere biology
- RNA-protein interactions
Background:
- Telomerase ribonucleoprotein (RNP) complexes exhibit divergent biogenesis and protein complements across species.
- While yeast and mammalian telomerase are well-studied, plant telomerase remains less understood.
- Arabidopsis thaliana telomerase previously identified accessory factors AtNAP57 and AtPOT1a, which stimulate processivity.
Purpose of the Study:
- To investigate the protein composition and function of telomerase in Arabidopsis thaliana using quantitative mass spectrometry.
- To identify novel accessory factors involved in Arabidopsis telomerase biogenesis and activity.
- To elucidate the role of AtLa1 in telomerase function and its interaction with telomerase RNA (AtTR).
Main Methods:
- Quantitative mass spectrometry (MS) to analyze purified Arabidopsis telomerase complexes.
- RNA-immunoprecipitation (RNA-IP) assays to confirm in vivo association of AtLa1 with AtTR.
- RNA interference (RNAi) to knockdown AtLa1 expression and assess telomerase activity.
- In vitro binding studies to characterize AtLa1-AtTR interactions.
Main Results:
- Dyskerin (AtNAP57) and AtPOT1a were unexpectedly absent in purified telomerase complexes.
- AtLa1, an RNA-binding factor, was highly enriched and confirmed to associate with AtTR in vivo.
- AtLa1 knockdown significantly diminished telomerase activity, indicating its essential role.
- AtLa1 binds AtTR via its UUU-3'OH and a plant-specific three-way junction (TWJ), a region also involved in AtNAP57 binding.
- AtLa1 did not stimulate telomerase activity in vitro, suggesting a role in an earlier biogenesis step.
Conclusions:
- Arabidopsis telomerase employs AtLa1 as a crucial accessory factor, distinct from previously identified proteins.
- AtLa1's interaction with AtTR and its essentiality suggest a role in telomerase maturation or assembly.
- The data indicate a potential competition or sequential binding between AtLa1 and AtNAP57 for AtTR.
- Arabidopsis telomerase utilizes a combination of accessory factors, offering insights into telomerase evolution and biogenesis mechanisms across eukaryotes.
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