Evolution of the Arabidopsis telomerase RNA

Mark A. Beilstein, Amy E. Brinegar, Dorothy E. Shippen

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

The telomerase reverse transcriptase promotes genome integrity by continually synthesizing a short telomere repeat sequence on chromosome ends. Telomerase is a ribonucleoprotein complex whose integral RNA subunitTER contains a template domain with a sequence complementary to the telomere repeat that is reiteratively copied by the catalytic subunit. Although TER harbors well-conserved secondary structure elements, its nucleotide sequence is highly divergent, even among closely related organisms. Thus, it has been extremely challenging to identify TER orthologs by bioinformatics strategies. Recently, TER was reported in the flowering plant, Arabidopsis thaliana. In contrast to other model organisms, A. thaliana encodes two TER subunits, only one of which is required to maintain telomere tracts in vivo. Here we investigate the evolution of the loci that encode TER in Arabidopsis by comparison to the same locus in its close relatives. We employ a combination of PCR and bioinformatics approaches to identify putative TER loci based on syntenic regions flanking theTERI andTER2 loci of A. thaliana. Unexpectedly, we discovered that the genomic regions encoding the two A. thalianaJEHs occur as a single locus in other Brassicaceae. Moreover, we find striking sequence divergence within the telomere template domain of putativeTERs from Brassicaceae, including some orthologous loci that completely lack a template domain. Finally, evolution of the locus is characterized by lineage-specific events rather than changes shared among closely related species. We conclude that the ArabidopsisTER duplication occurred very recently, and further that changes at this locus in other Brassicaceae indicate the process of TER evolution may be different in plants compared with vertebrates and yeast.

Original languageEnglish (US)
Article numberArticle 188
JournalFrontiers in Genetics
Volume3
Issue numberSEP
DOIs
StatePublished - 2012

Keywords

  • Brassicaceae
  • Gene duplication
  • Phylogenetics
  • TER
  • Telomerase

ASJC Scopus subject areas

  • Molecular Medicine
  • Genetics
  • Genetics(clinical)

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