Arabidopsis thaliana
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA145305 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:RNA silencing is a mechanism for regulating gene expression at the transcriptional and post-transcriptional levels. Its functions include regulating endogenous gene expression and protecting the cell against viruses and invading transposable elements (TEs). A key component of the mechanism is small RNAs (sRNAs) of 21-24 nucleotides (nt) in length, which direct the silencing machinery in a sequence specific manner to target nucleic acids. sRNAs of 24 nt are involved in methylation of cytosine residues of target loci in three sequence contexts (CG, CHG and CHH), referred to as RNA-directed DNA methylation (RdDM). We previously demonstrated that 24 nt sRNAs are mobile from shoot to root in Arabidopsis thaliana. In this study we demonstrated that methylation of thousands of loci in root tissues is dependent upon mobile sRNAs from the shoot. Furthermore, we found that mobile sRNA-dependent DNA methylation occurs predominantly in non-CG contexts. These findings were made using base-resolution next generation sequencing approaches and genome wide analyses. Specific classes of short TEs are the predominant targets of mobile sRNA-dependent DNA methylation; classes typically found in gene-rich euchromatic regions. Mobile sRNA-regulated genes were also identified. Mechanistically, we demonstrate that mobile sRNA-dependent non-CG methylation is largely independent of the CMT2/3 RdDM pathway but dependent upon the DRM1/DRM2 RdDM pathway. This is in contrast to non-mobile sRNA-dependent DNA methylation, which predominantly depends upon the CMT2/3 RdDM pathway. These data are complementary to the small RNA sequencing data from Arabidopsis root grafts described in Molnar et al (Science, 2010 May 14;328(5980):872-5).
2016-01-04 | E-MTAB-3473 | biostudies-arrayexpress
Project description:RNA-directed DNA methylation (RdDM) is a small interfering RNA (siRNA)-mediated epigenetic modification that contributes to transposon silencing in plants. RdDM requires a complex transcriptional machinery that includes specialized RNA polymerases, named Pol IV and Pol V, as well as chromatin remodelling proteins, transcription factors, RNA binding proteins, and other plant-specific proteins whose functions are not yet clarified. In Arabidopsis thaliana, DICER-LIKE3 and members of the ARGONAUTE4 group of AROGONAUTE (AGO) proteins are involved, respectively, in generating and using 24-nt siRNAs that trigger methylation and transcriptional gene silencing (TGS) of homologous promoter sequences. AGO proteins act in silencing effector complexes by anchoring the 3â and 5â ends of the guide siRNAs at their N-terminal PAZ domain and MID domain, respectively. In addition, many AGO proteins cleave complementary target RNAs through an endonuclease (âslicerâ) activity in their C-terminal PIWI domain. AGO4 is the main AGO protein implicated in the RdDM pathway. Here we report the identification of the related AGO6 in a forward genetic screen for mutants defective in RdDM and TGS in shoot and root apical meristems in Arabidopsis thaliana. The identification of AGO6, and not AGO4, in our screen is consistent with the primary expression of AGO6 in shoot and root growing points and the preferential association of Pol V with AGO6. Examination of siRNA abundance in the trasngenic wild type plant (contains trigger and silencer transgenes) and the ago6-4 mutant.
2011-12-01 | E-GEOD-28537 | biostudies-arrayexpress
Project description:RNA-directed DNA methylation (RdDM) is a small interfering RNA (siRNA)-mediated epigenetic modification that contributes to transposon silencing in plants. RdDM requires a complex transcriptional machinery that includes specialized RNA polymerases, named Pol IV and Pol V, as well as chromatin remodelling proteins, transcription factors, RNA binding proteins, and other plant-specific proteins whose functions are not yet clarified. In Arabidopsis thaliana, DICER-LIKE3 and members of the ARGONAUTE4 group of AROGONAUTE (AGO) proteins are involved, respectively, in generating and using 24-nt siRNAs that trigger methylation and transcriptional gene silencing (TGS) of homologous promoter sequences. AGO proteins act in silencing effector complexes by anchoring the 3â and 5â ends of the guide siRNAs at their N-terminal PAZ domain and MID domain, respectively. In addition, many AGO proteins cleave complementary target RNAs through an endonuclease (âslicerâ) activity in their C-terminal PIWI domain. AGO4 is the main AGO protein implicated in the RdDM pathway. Here we report the identification of the related AGO6 in a forward genetic screen for mutants defective in RdDM and TGS in shoot and root apical meristems in Arabidopsis thaliana. The identification of AGO6, and not AGO4, in our screen is consistent with the primary expression of AGO6 in shoot and root growing points and the preferential association of Pol V with AGO6.
2011-12-01 | GSE28537 | GEO
Project description:We grafted Transcriptional Gene Silencing (TGS)-inducing wild type Arabidopsis and a mutant that is compromised in 24 nucleotide (nt) small RNA (sRNA) production onto a wild type reporter line. We observed that 21-24 nt sRNAs were transmitted across a graft union yet only the 24 nt sRNAs directed RNA-dependent DNA methylation (RdDM) and TGS of a transgene promoter in meristematic cells. Analysis of sRNAs associated with mobile TGS by deep sequencing, biological replicates. 10 unique samples, 5 biological replicates.
2011-10-23 | E-GEOD-31651 | biostudies-arrayexpress
Project description:In maize, 24-nt phased, secondary small interfering RNAs (phasiRNAs) are abundant in meiotic stage anthers, but their distribution and functions are not precisely known. Using laser capture microdissection we analyzed tapetal cells, meiocytes, and other somatic cells at several stages of anther development to establish the timing of 24-PHAS precursor transcripts and the 24-nt phasiRNA products. By integrating RNA and small RNA (sRNA) profiling plus single-molecule and sRNA FISH (smFISH or sRNA-FISH) spatial detection, we demonstrate that the tapetum is the primary site of 24-PHAS precursor and Dcl5 transcripts and the resulting 24-nt phasiRNAs. Interestingly, 24-nt phasiRNAs accumulate in all cell types, with the highest levels in meiocytes, followed by tapetum. Our data support the conclusion that 24-nt phasiRNAs are mobile from tapetum to meiocytes and to other somatic cells. We discuss possible roles for 24-nt phasiRNAs in anther cell types.
2022-03-23 | GSE182588 | GEO
Project description:A silencing signal in plants with an RNA specificity determinant moves through plasmodesmata and the phloem. To identify the mobile RNA we grafted Arabidopsis thaliana shoots to roots that would be a recipient for the silencing signal. Using high throughput sequencing as a sensitive detection method and mutants to block small RNA (sRNA) biogenesis in either source or recipient tissue, we detected endogenous and transgene specific sRNA that moved across the graft union. Surprisingly we found that the mobile endogenous sRNAs account for a substantial proportion of the sRNA in roots and we provide evidence that 24nt mobile sRNAs direct epigenetic modifications in the genome of the recipient cells. Mobile sRNA thus represents a mechanism for transmitting the specification of epigenetic modification and could affect genome defence and responses to external stimuli that have persistent effects in plants. Keywords: Small RNA Analysis, Epigenetics 34 unique samples, 15 Biological Replicates
2010-03-24 | E-GEOD-20663 | biostudies-arrayexpress
Project description:Secondary metabolites are involved in the plant stress response. Among these are scopolin and its active form scopoletin, which are coumarin derivatives associated with reactive oxygen species scavenging and pathogen defence. Here we show that in Arabidopsis thaliana, scopolin accumulation can be induced in the root by osmotic stress and in the leaf by low temperature stress. A genetic screen for altered scopolin levels in Arabidopsis thaliana identified a mutant compromised for scopolin accumulation in response to stress; the lesion was present in a homologue of THO1, the product of which contributes to the THO/TREX complex. The THO/TREX complex contributes to RNA silencing, supposedly by trafficking precursors of small RNAs. Mutants carrying defective THO and RDR6 genes were impaired with respect to scopolin accumulation in response to stress, suggesting a mechanism based on RNA silencing like the transacting small interfering RNA pathway which requires THO/TREX and RDR6 function.
2018-02-05 | MTBLS389 | MetaboLights
Project description:A silencing signal in plants with an RNA specificity determinant moves through plasmodesmata and the phloem. To identify the mobile RNA we grafted Arabidopsis thaliana shoots to roots that would be a recipient for the silencing signal. Using high throughput sequencing as a sensitive detection method and mutants to block small RNA (sRNA) biogenesis in either source or recipient tissue, we detected endogenous and transgene specific sRNA that moved across the graft union. Surprisingly we found that the mobile endogenous sRNAs account for a substantial proportion of the sRNA in roots and we provide evidence that 24nt mobile sRNAs direct epigenetic modifications in the genome of the recipient cells. Mobile sRNA thus represents a mechanism for transmitting the specification of epigenetic modification and could affect genome defence and responses to external stimuli that have persistent effects in plants. Keywords: Small RNA Analysis, Epigenetics
2010-03-24 | GSE20663 | GEO
Project description:Transposable elements (TEs) comprise a substantial portion of many eukaryotic genomes and are typically transcriptionally silenced. RNA–dependent RNA polymerase 2 (RDR2) is a component of the RNA–directed DNA methylation (RdDM) silencing pathway. In maize, loss of mediator of paramutation1 (mop1) encoded RDR2 function results in reactivation of transcriptionally silenced Mu transposons and a substantial reduction in the accumulation of 24 nt short-interfering RNAs (siRNAs) that recruit RNA silencing components. An RNA–seq experiment conducted on shoot apical meristems (SAMs) revealed that, as expected based on a model in which RDR2 generates 24 nt siRNAs that suppress expression, most differentially expressed DNA TEs (78%) were up-regulated in the mop1 mutant. In contrast, most differentially expressed retrotransposons (68%) were down-regulated. This striking difference suggests that distinct silencing mechanisms are applied to different silencing templates. In addition, 6,000 genes (24% of analyzed genes), including nearly 80% (286/361) of genes in chromatin modification pathways, were differentially expressed. Overall, two-thirds of differentially regulated genes were down-regulated in the mop1 mutant. This finding suggests that RDR2 plays a significant role in regulating the expression of not only transposons, but also of genes. A re-analysis of existing small RNA data identified both RDR2–sensitive and RDR2–resistant species of 24 nt siRNAs that we hypothesize may at least partially explain the complex changes in the expression of genes and transposons observed in the mop1 mutant.
2009-11-20 | GSE16789 | GEO
Project description:Transitive silencing of mobile small RNAs in Arabidopsis Pollen
| PRJNA281937 | ENA