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La1: an evolutionarily conserved player in the Arabidopsis telomerase complex
Chinmay Phadke1, Saundarya K Mishra1, Jiarui Song1
1Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843-2128, USA.
Plant Cell Reports
|August 6, 2026
Summary
Researchers identified AtLa1, a novel protein essential for plant telomerase function and maturation in Arabidopsis. This discovery sheds light on telomerase biogenesis and evolution in plants, distinct from mammals and single-cell organisms.
Area of Science:
- Plant molecular biology
- Telomere biology
- Biochemistry
Background:
- Plant telomerase biogenesis and protein composition remain poorly understood.
- Arabidopsis telomerase involves catalytic subunit TERT, templating RNA TR, and accessory protein AtNAP57.
- La-related proteins function as RNA chaperones in various telomerase complexes.
Purpose of the Study:
- To identify novel protein constituents of Arabidopsis telomerase using quantitative mass spectrometry.
- To elucidate the functional role of newly identified proteins in telomerase activity and telomere maintenance.
- To investigate the interaction of these proteins with telomerase RNA (AtTR) and their implications in telomerase biogenesis.
Main Methods:
- Quantitative mass spectrometry (qMS) to profile Arabidopsis telomerase complex.
- RNA-immunoprecipitation (RNA-IP) assays to confirm protein-RNA interactions.
- RNA interference (RNAi)-mediated knockdown to assess protein function in vivo.
- In vitro binding studies to map protein-RNA interaction sites.
Main Results:
- Quantitative mass spectrometry identified AtLa1, a novel telomerase-associated protein, as a homolog of yeast and ciliate proteins.
- AtLa1 is essential for telomerase function in vivo, as evidenced by diminished telomerase activity upon AtLa1 knockdown.
- In vitro studies showed AtLa1 binds AtTR at a specific three-way junction (TWJ) also recognized by AtNAP57.
Conclusions:
- AtLa1 is a crucial component for Arabidopsis telomerase maturation and function.
- The interaction of AtLa1 and AtNAP57 with AtTR suggests a potential competition or sequential binding during telomerase biogenesis.
- Investigating Arabidopsis telomerase offers insights into the evolution and diverse mechanisms of telomerase biogenesis across different organisms.
Related Concept Videos
02:41Telomeres and Telomerase
In eukaryotic DNA replication, a single-stranded DNA fragment remains at the end of a chromosome after the removal of the final primer. This section of DNA cannot be replicated in the same manner as the rest of the strand because there is no 3’ end to which the newly synthesized DNA can attach. This non-replicated fragment results in gradual loss of the chromosomal DNA during each cell duplication. Additionally, it can induce a DNA damage response by enzymes that recognize single-stranded DNA.
02:41Telomeres and Telomerase
In eukaryotic DNA replication, a single-stranded DNA fragment remains at the end of a chromosome after the removal of the final primer. This section of DNA cannot be replicated in the same manner as the rest of the strand because there is no 3’ end to which the newly synthesized DNA can attach. This non-replicated fragment results in gradual loss of the chromosomal DNA during each cell duplication. Additionally, it can induce a DNA damage response by enzymes that recognize single-stranded DNA.
01:29Replication in Eukaryotes
In eukaryotic cells, DNA replication is highly conserved and tightly regulated. Multiple linear chromosomes must be duplicated with high fidelity before cell division, so there are many proteins that fulfill specialized roles in the replication process. Replication occurs in three phases: initiation, elongation, and termination, and ends with two complete sets of chromosomes in the nucleus.
Many Proteins Orchestrate Replication at the Origin
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02:31Replication in Eukaryotes
Overview
02:35Transcription Elongation Factors
Transcription elongation is a dynamic process that alters depending upon the sequence heterogeneity of the DNA being transcribed. Hence, it is not surprising that the elongation complex's composition also varies along the way while transcribing a gene.
The transcription elongation is regulated via pausing of RNA polymerase on several occasions during transcription. In bacteria, these halts are necessary because the transcription of DNA into mRNA is coupled to the translation of that mRNA into a...
The transcription elongation is regulated via pausing of RNA polymerase on several occasions during transcription. In bacteria, these halts are necessary because the transcription of DNA into mRNA is coupled to the translation of that mRNA into a...
02:35Transcription Elongation Factors
Transcription elongation is a dynamic process that alters depending upon the sequence heterogeneity of the DNA being transcribed. Hence, it is not surprising that the elongation complex's composition also varies along the way while transcribing a gene.
The transcription elongation is regulated via pausing of RNA polymerase on several occasions during transcription. In bacteria, these halts are necessary because the transcription of DNA into mRNA is coupled to the translation of that mRNA into a...
The transcription elongation is regulated via pausing of RNA polymerase on several occasions during transcription. In bacteria, these halts are necessary because the transcription of DNA into mRNA is coupled to the translation of that mRNA into a...