Similar Datasets
Project description:RNA-directed DNA methylation (RdDM) plays an essential role in transposable element (TE) silencing in plants. In the Arabidopsis RdDM pathway, the DDR complex containing DRD1, DMS3, and RDM1, is necessary for recruiting Pol V to transcribe scaffold RNA. Although the role of DDR is known, the mechanism by which the DDR complex is regulated remains unexplored. Here, we demonstrate that the Anaphase Promoting Complex/Cyclosome (APC/C) monitors the assembly of the DDR complex by targeting DMS3 for degradation. We show that a subset of Pol V-dependent RdDM loci are de-repressed in apc/c mutants, accompanied by defective recruitment and transcription of Pol V. APC/C targets DMS3 for ubiquitination and degradation in a D box-dependent manner, and the D-box-mutated DMS3 fails to complement the dms3 mutant. Competitive binding assays shows that the dosage of DMS3 is critical for the assembly of the DDR complex, and in vivo gel filtration analysis shows that the assembly of both DDR and Pol V is compromised in the apc8 mutant. These findings uncover a safeguard role of APC/C-mediated DMS3 degradation in the assembly of the DDR complex, and provide a direct link between selective protein degradation and RdDM.
2019-01-31 | GSE106970 | GEO
Project description:RNA-directed DNA methylation (RdDM) plays an essential role in transposable element (TE) silencing in plants. In the Arabidopsis RdDM pathway, the DDR complex containing DRD1, DMS3, and RDM1, is necessary for recruiting Pol V to transcribe scaffold RNA. Although the role of DDR is known, the mechanism by which the DDR complex is regulated remains unexplored. Here, we demonstrate that the Anaphase Promoting Complex/Cyclosome (APC/C) monitors the assembly of the DDR complex by targeting DMS3 for degradation. We show that a subset of Pol V-dependent RdDM loci are de-repressed in apc/c mutants, accompanied by defective recruitment and transcription of Pol V. APC/C targets DMS3 for ubiquitination and degradation in a D box-dependent manner, and the D-box-mutated DMS3 fails to complement the dms3 mutant. Competitive binding assays shows that the dosage of DMS3 is critical for the assembly of the DDR complex, and in vivo gel filtration analysis shows that the assembly of both DDR and Pol V is compromised in the apc8 mutant. These findings uncover a safeguard role of APC/C-mediated DMS3 degradation in the assembly of the DDR complex, and provide a direct link between selective protein degradation and RdDM.
2019-01-31 | GSE106971 | GEO
Project description:The Anaphase Promoting Complex/Cyclosome degrades DMS3 to maintain RNA-directed DNA Methylation in Arabidopsis
| PRJNA418691 | ENA
Project description:The Anaphase Promoting Complex/Cyclosome degrades DMS3 to maintain RNA-directed DNA Methylation in Arabidopsis [lncRNA-seq]
| PRJNA418706 | ENA
Project description:The Anaphase Promoting Complex/Cyclosome degrades DMS3 to maintain RNA-directed DNA Methylation in Arabidopsis [small RNA-seq]
| PRJNA418705 | ENA
Project description:In plants, double-stranded RNA that is processed to short RNAs approximately 21-24 nt in length can trigger two types of epigenetic gene silencing. Posttranscriptional gene silencing, which is related to RNA interference in animals and quelling in fungi, involves targeted elimination of homologous mRNA in the cytoplasm. RNA-directed DNA methylation involves de novo methylation of almost all cytosine residues within a region of RNA-DNA sequence identity. RNA-directed DNA methylation is presumed to be responsible for the methylation observed in protein coding regions of posttranscriptionally silenced genes. Moreover, a type of transcriptional gene silencing and de novo methylation of homologous promoters in trans can occur if a double-stranded RNA contains promoter sequences. Although RNA-directed DNA methylation has been described so far only in plants, there is increasing evidence that RNA can also target genome modifications in other organisms. To understand how RNA directs methylation to identical DNA sequences and how changes in chromatin configuration contribute to initiating or maintaining DNA methylation induced by RNA, a promoter double-stranded RNA-mediated transcriptional gene silencing system has been established in Arabidopsis. A genetic analysis of this system is helping to unravel the relationships among RNA signals, DNA methylation, and chromatin structure.
| S-EPMC139914 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below.
2012-05-26 | GSE36148 | GEO
Project description:Faithful chromosome segregation is required for both mitotic and meiotic cell divisions and is regulated by multiple mechanisms including the anaphase-promoting complex/cyclosome (APC/C), which is the largest known E3 ubiquitin-ligase complex and has been implicated in regulating chromosome segregation in both mitosis and meiosis in animals. However, the role of the APC/C during plant meiosis remains largely unknown. Here, we show that Arabidopsis APC8 is required for male meiosis. We used a combination of genetic analyses, cytology and immunolocalisation to define the function of AtAPC8 in male meiosis. Meiocytes from apc8-1 plants exhibit several meiotic defects including improper alignment of bivalents at metaphase I, unequal chromosome segregation during anaphase II, and subsequent formation of polyads. Immunolocalisation using an antitubulin antibody showed that APC8 is required for normal spindle morphology. We also observed mitotic defects in apc8-1, including abnormal sister chromatid segregation and microtubule morphology. Our results demonstrate that Arabidopsis APC/C is required for meiotic chromosome segregation and that APC/C-mediated regulation of meiotic chromosome segregation is a conserved mechanism among eukaryotes.
| S-EPMC6771777 | biostudies-literature
Project description:RNA-directed DNA methylation (RdDM) is an important de novo DNA methylation pathway in plants. Small interfering RNAs (siRNAs) generated by Dicers from RNA polymerase IV (Pol IV) transcripts are thought to guide sequence-specific DNA methylation. To gain insight into the mechanism of RdDM, we performed whole-genome bisulfite sequencing of a collection of Arabidopsis mutants, including plants deficient in Pol IV (nrpd1) or Dicer (dcl1/2/3/4) activity. Unexpectedly, of the RdDM target loci that required Pol IV and/or Pol V, only 16% were fully dependent on Dicer activity. DNA methylation was partly or completely independent of Dicer activity at the remaining Pol IV- and/or Pol V-dependent loci, despite the loss of 24-nt siRNAs. Instead, DNA methylation levels correlated with the accumulation of Pol IV-dependent 25-50 nt RNAs at most loci in Dicer mutant plants. Our results suggest that RdDM in plants is largely guided by a previously unappreciated class of Dicer-independent non-coding RNAs, and that siRNAs are required to maintain DNA methylation at only a subset of loci.
| S-EPMC4816133 | biostudies-literature
Project description:During RNA-directed DNA methylation (RdDM), the DDR complex, composed of DRD1, DMS3, and RDM1, is responsible for recruiting DNA polymerase V (Pol V) to silence transposable elements (TEs) in plants. However, how the DDR complex is regulated remains unexplored. Here, we show that the anaphase-promoting complex/cyclosome (APC/C) regulates the assembly of the DDR complex by targeting DMS3 for degradation. We found that a substantial set of RdDM loci was commonly de-repressed in apc/c and pol v mutants, and that the defects in RdDM activity resulted from up-regulated DMS3 protein levels, which finally caused reduced Pol V recruitment. DMS3 was ubiquitinated by APC/C for degradation in a D box-dependent manner. Competitive binding assays and gel filtration analyses showed that a proper level of DMS3 is critical for the assembly of the DDR complex. Consistent with the importance of the level of DMS3, overaccumulation of DMS3 caused defective RdDM activity, phenocopying the apc/c and dms3 mutants. Moreover, DMS3 is expressed in a cell cycle-dependent manner. Collectively, these findings provide direct evidence as to how the assembly of the DDR complex is regulated and uncover a safeguarding role of APC/C in the regulation of RdDM activity.
| S-EPMC6397581 | biostudies-literature