Project description:The Arabidopsis thaliana multi-subunit RNA Polymerase IV largest subunit DeCL domain was functionally assessed with an NRPD1 DeCL domain deletion construct.
Project description:The Arabidopsis thaliana multi-subunit RNA Polymerase IV largest subunit DeCL domain was functionally assessed with an NRPD1 DeCL domain deletion construct.
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.
Project description:Assessment of the Pol IV largest subunit, NRPD1, DeCL domain deletion construct to rescue Pol IV-dependent DNA methylation in the nrpd1-3 mutant (Bisulfite-Seq).
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.
Project description:RNA polymerase II (Pol II) was immunoprecipitated from Arabidopsis thaliana seedlings, using antibodies that specifically recognize: 1) C’ terminal Domain (CTD), 2) CTD Serine 5 Phosphorylation and 3) CTD Serine 2 Phosphorylation. Proteins that co-immunoprecipitate with different Pol II pools were analysed.
Project description:The plant-specific DNA-dependent RNA polymerase V (Pol V) evolved from Pol II to function in an RNA-directed DNA methylation pathway. Here, we have identified targets of Pol V in Arabidopsis thaliana on a genome-wide scale using ChIP-seq of NRPE1, the largest catalytic subunit of Pol V. We found that Pol V is enriched at promoters and evolutionarily recent transposons. This localization pattern is highly correlated with Pol V-dependent DNA methylation and small RNA accumulation. We also show that genome-wide association of Pol V with chromatin is dependent on all members of a putative chromatin-remodeling complex termed DDR. Our study presents the first genome-wide view of Pol V occupancy and sheds light on the mechanistic basis of Pol V localization. Furthermore, these findings suggest a role for Pol V and RNA-directed DNA methylation in genome surveillance and in responding to genome evolution. For wild type plants (ecotype Columbia) and nrpe1 mutants whole-genome small RNA (sRNA-seq) and bisulfite sequencing (BS-seq) was performed. In addition whole genome chromatin immunoprecipitation (ChIP-seq) was performed on wild type (ecotype Columbia) plants as a negative control with experimentals consiting of wild type plants carrying a C-terminally epitope tagged (2XFLAG) NRPE1, as well as the NRPE1-FLAG construct in drd1, dms3, and rdm1 mutant backgrounds.
Project description:We report genome-wide detection of long noncoding RNA (lncRNA) generate by Pol V in transcriptional gene silencing in Arabidopsis thaliana. We further show that most of these transcripts are bound by AGO4. RNA immunoprecipitation followed by high-throughput sequencing (RIP-seq) RNA immunoprecipitation with an anti-AGO4 antibody was performed in one biological replicate and included Col-0, nrpe1, and ago4-1; RNA immunoprecipitation with an anti-NRPE1 (largest subunit of Pol V) was performed in two replicates; replicate 1 included Col-0 and nrpe1, replicated two included Col-0, nrpe1, ago4-1, and idn2-1
Project description:Assessment of the Pol IV largest subunit, NRPD1, DeCL domain deletion construct to rescue Pol IV-dependent siRNAs in the nrpd1-3 mutant (sRNA).
