tRNA ADENOSINE DEAMINASE 3 is required for telomere maintenance in Arabidopsis thaliana
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ORIGINAL ARTICLE
tRNA ADENOSINE DEAMINASE 3 is required for telomere maintenance in Arabidopsis thaliana Sreyashree Bose1 · Ana Victoria Suescún1,2 · Jiarui Song1 · Claudia Castillo‑González1 · Behailu Birhanu Aklilu1,3 · Erica Branham1 · Ryan Lynch1 · Dorothy E. Shippen1,4 Received: 9 July 2020 / Accepted: 4 September 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Key message tRNA Adenosine Deaminase 3 helps to sustain telomere tracts in a telomerase-independent fashion, likely through regulating cellular metabolism. Abstract Telomere length maintenance is influenced by a complex web of chromatin and metabolism-related factors. We previously reported that a lncRNA termed AtTER2 regulates telomerase activity in Arabidopsis thaliana in response to DNA damage. AtTER2 was initially shown to partially overlap with the 5′ UTR of the tRNA ADENOSINE DEAMINASE 3 (TAD3) gene. However, updated genome annotation showed that AtTER2 was completely embedded in TAD3, raising the possibility that phenotypes ascribed to AtTER2 could be derived from TAD3. Here we show through strand-specific RNA-Seq, strandspecific qRT-PCR and bioinformatic analyses that AtTER2 does not encode a stable lncRNA. Further examination of the original tad3 (ter2-1/tad3-1) mutant revealed expression of an antisense transcript driven by a cryptic promoter in the T-DNA. Hence, a new hypomorphic allele of TAD3 (tad3-2) was examined. tad3-2 mutants showed hypersensitivity to DNA damage, but no deregulation of telomerase, suggesting that the telomerase phenotype of tad3-1 mutants reflects an off-target effect. Unexpectedly, however, tad3-2 plants displayed progressive loss of telomeric DNA over successive generations that was not accompanied by alteration of terminal architecture or end protection. The phenotype was exacerbated in plants lacking the telomerase processivity factor POT1a, indicating that TAD3 promotes telomere maintenance through a non-canonical, telomerase-independent pathway. The transcriptome of tad3-2 mutants revealed significant dysregulation of genes involved in auxin signaling and glucosinolate biosynthesis, pathways that intersect the stress response, cell cycle regulation and DNA metabolism. These findings indicate that the TAD3 locus indirectly contributes to telomere length homeostasis by altering the metabolic profile in Arabidopsis. Keywords Telomerase · Telomerase RNA · AtTER2 · Translation · Cell cycle · Auxin Communicated by Günther Hahne. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00299-020-02594-0) contains supplementary material, which is available to authorized users. * Dorothy E. Shippen [email protected] 1
Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA
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Present Address: Facultad de Ciencias, Instituto de Ciencias Ambientales Y Evolutivas, Universidad Austral de Chile, Valdivia, Chile
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KWS Gateway Research Center, LLC, 1005 N Warson Rd, BRDG Park, St. Louis, MO 63132, USA
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Depart
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