Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

DNA Topoisomerase 1a Promotes RNA-directed DNA Methylation and Histone Lysine 9 Dimethylation at Transposable Elements in Arabidopsis [RNA-Seq]

ABSTRACT: RNA-directed DNA methylation (RdDM) is a transcriptional silencing mechanism mediated by small and long noncoding RNAs produced by the plant-specific RNA polymerases Pol IV and Pol V, respectively. Through a chemical genetics screen with a luciferase-based DNA methylation reporter, LUCL, we found that camptothecin, a compound with anti-cancer properties that targets DNA topoisomerase 1a (TOP1a) was able to de-repress LUCL by reducing its DNA methylation and H3K9 dimethylation (H3K9me2) levels. Further studies with Arabidopsis top1a mutants showed that TOP1a promotes RdDM by facilitating the production of Pol V-dependent long non-coding RNAs, AGONAUTE4 recruitment and H3K9me2 deposition at transposable elements (TEs). 5 small RNA libraries were sequenced

ORGANISM(S): Arabidopsis thaliana

SUBMITTER: Lei Gao

PROVIDER: E-GEOD-50719 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

DNA topoisomerase 1α promotes transcriptional silencing of transposable elements through DNA methylation and histone lysine 9 dimethylation in Arabidopsis.

Dinh Thanh Theresa TT Gao Lei L Liu Xigang X Li Dongming D Li Shengben S Zhao Yuanyuan Y O'Leary Michael M Le Brandon B Schmitz Robert J RJ Manavella Pablo A PA Li Shaofang S Weigel Detlef D Pontes Olga O Ecker Joseph R JR Chen Xuemei X

PLoS genetics 20140703 7

RNA-directed DNA methylation (RdDM) and histone H3 lysine 9 dimethylation (H3K9me2) are related transcriptional silencing mechanisms that target transposable elements (TEs) and repeats to maintain genome stability in plants. RdDM is mediated by small and long noncoding RNAs produced by the plant-specific RNA polymerases Pol IV and Pol V, respectively. Through a chemical genetics screen with a luciferase-based DNA methylation reporter, LUCL, we found that camptothecin, a compound with anti-cancer ...[more]

PMID: 24992598

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Project description:miRNA levels depend on both biogenesis and turnover. The methyltransferase HEN1 stabilizes plant miRNAs, animal piRNAs, and siRNAs in both kingdoms via 3' terminal methylation. Loss of HEN1 in plants results in non-templated oligo-uridylation and accelerated degradation of miRNAs. In hen1 mutants from Arabidopsis and rice, we found that the patterns of miRNA truncation and uridylation differ substantially among miRNA families, but such patterns for the same miRNA are conserved between species. miR166 and miR163 are truncated predominantly to ~17 and ~16 nt, and subsequently recover via uridylation to approximately their original sizes, 21 and 24 nt, suggesting that in these cases miRNA truncation triggers uridylation. miR171 is untruncated but uridylated to 22 nt in hen1 mutants, gaining the ability to trigger production of phased, secondary siRNAs. Truncated and tailed variants were bound by ARGONAUTE1 (AGO1) in hen1, implying that these events occur while miRNAs are still bound by AGO1. Unexpectedly, a portion of miR158 in wildtype remains unmethylated and thus subject to uridylation and destabilization, suggesting that plants naturally utilize miRNA methylation to modulate miRNA accumulation. Our results suggest that the AGO1-containing RISC complex may undergo programming to reflect each bound miRNA, determining a defined, distinct decay destiny. In this analysis, we sequenced sRNAs from two hen1 mutant alleles in Arabidopsis and three hen1 alleles in rice. In Arabidopsis, the strong hen1-1 allele in the Landsberg erecta (Ler) ecotype is the first hen1 mutant and emerged from an enhancer screen in the hua1-1/hua2-1 background, and hen1-8 in the Columbia (Col) background is a weak allele. In rice, WAVY LEAF1 (WAF1) is the ortholog of Arabidopsis HEN1, and two mutant alleles waf1-1 and waf1-2 each bear a single-base substitution leading to a premature stop codon in the second exon and a non-functional splicing site of the fourth intron, respectively. We identified a third mutant allele of the rice HEN1 gene (Oshen1-3 from the Korean (POSTEC) rice T-DNA mutant population).

Dataset Information

DNA Topoisomerase 1a Promotes RNA-directed DNA Methylation and Histone Lysine 9 Dimethylation at Transposable Elements in Arabidopsis [RNA-Seq]

Publications

DNA topoisomerase 1α promotes transcriptional silencing of transposable elements through DNA methylation and histone lysine 9 dimethylation in Arabidopsis.

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