| RT-PCR |
telomere shortening |
down-regulated |
N/A |
We show that TER2 is spliced and its 3' end is truncated in vivo to generate a third TER isoform, TER2S. Plants null for TER2 display increased telomerase enzyme activity, while TER2 overexpression inhibits telomere synthesis from TER1 and leads to telomere shortening. These findings argue that TER2 negatively regulates telomerase by sequestering TERT in a nonproductive RNP complex. Introduction of DNA double-strand breaks by zeocin leads to an immediate and specific spike in TER2 and a concomitant decrease in telomerase enzyme activity. This response is not triggered by replication stress or telomere dysfunction and is abrogated in ter2 mutants. We conclude that Arabidopsis telomerase is modulated by TER2, a novel DNA damage induced noncoding RNA that works in concert with the canonical TER to promote genome integrity. (Cifuentes-Rojas et al., 2012) TER2 (GenBank accession no. HQ401285), was also uncovered. TER2 maps to chromosome 5, in the opposite direction and partially overlapping with the 5′ UTR of another unknown protein coding gene, AT5G24670. TER2 also contains 1.5 copies of the Arabidopsis telomere repeat. RT-PCR confirmed that both TER1 and TER2 RNAs were enriched in purified telomerase fractions, in contrast to a U6 snRNA control. (Cifuentes-Rojas et al., 2011) As the essential RNA subunit of telomerase, TER1 is required for telomere maintenance, while TER2 is assembled in distinct RNP complex (es)to modulate telomerase activity in response to DNA damage. (Wang et al., 2014) |
23109676, 21164032, 24398630 |
PLNlncRbase
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