Project description:Post-transcriptional gene silence (PTGS) is employed in plants to shut down transgenes, invading viral genes and a certain group of endogenous genes. Meanwhile, it is not clear how the risk of expansive PTGS from endogenous genes featured by transitive siRNA production is minimized. Here we demonstrate two essential components of the SKI complex in cytoplasmic 3’-5’ mRNA decay pathway, SKI2 and SKI3, function as negative regulators of transgene PTGS in Arabidopsis. The ski2 mutants manifested severe synthetic phenotypes with a 5’-3’ exoribonuclease mutant, ein5, which were substantially suppressed by the PTGS mutants, rdr6 and ago1. RDR6 is essential for the altered gene expression in ein5 ski2 on a transcriptome-wide scale. mRNA-seq approach was used to investigate the physiological relevance veiled by the myriad developmental phenotypes in Col-0 (C), ein5-1 (e), ski2-3 (s), ein5-1 ski2-3 (es), rdr6-11 (r) and rdr6-11 ein5-1 ski2-3 (res). A number of endogenous genes, including many miRNA target genes, manifest transitive 21-22 nt siRNA production and compromised gene expression in ein5 ski2 in an RDR6-dependent manner. Taken together, our study brings to light a dual-safeguard system in preventing the expansive siRNA production by the 5’-3’ and 3’-5’ cytoplasmic mRNA decay pathways.
Project description:Next-generation Illumina sequencing technology was used to analyze small RNA associated with post-transcriptional gene silencing induced by intron-spliced hairpin RNA (ihpRNA) in Arabidopsis. The experimental induction of RNA silencing in plants often involves expression of transgenes encoding inverted repeat (IR) sequences to produce abundant dsRNAs that are processed into small RNAs (sRNAs). These sRNAs are key mediators of post-transcriptional gene silencing (PTGS) and determine the specificity of the inhibition of gene expression. Despite its broad utility as a research tool, IR-PTGS is only a partially understood mechanism of RNA silencing in plants. We generated four sets of 60 Arabidopsis plants, each containing IR transgenes expressing different configurations of uidA and CHALCONE SYNTHASE (CHS) gene fragments. The levels of PTGS were dependent on the orientation and position of the fragment in the IR construct. To investigate these differences, we characterized the sRNA profiles by Illumina sequencing of seven libraries generated from transgenic families showing different levels of IR-PTGS. Mapping of sRNA sequences to their corresponding transgene-derived and endogenous transcripts identified distinctive patterns of differential sRNA accumulation. Analyses of these patterns and peaks revealed similarities among sRNAs associated with IR-PTGS and endogenous sRNAs linked to uncapped mRNA decay. We also found unexpected associations between sRNA accumulation and the presence of predicted open reading frames in the trigger sequence. Our observations provide new guidelines for designing constructs to increase the efficiency of IR-PTGS. In addition, strong IR-PTGS affected the prevalence of endogenous sRNAs, which has implications for the use of PTGS for experimental or applied purposes.
Project description:FERONIA (FER) is a plasma membrane-localized receptor-like kinase (RLK) that belongs to the Catharantus roseus RLK1-like (CrRLK1L) subfamily. FER serves as a potential cell wall sensor that regulates multiple phytohormones, including ABA, JA, SA, BR, auxin, and ethyl, but the underlying regulatory mechanisms are still largely unknown. To further understand how FER regulates downstream signaling pathway, we performed FER-interacting proteins via immunoprecipitation-mass spectrometry (IP-MS) assay generated from FER-GFP transgenic plants.
Project description:Post-transcriptional gene silence (PTGS) is employed in plants to shut down transgenes, invading viral genes and a certain group of endogenous genes. Meanwhile, it is not clear how the risk of expansive PTGS from endogenous genes featured by transitive siRNA production is minimized. Here we demonstrate two essential components of the SKI complex in cytoplasmic 3 -5 mRNA decay pathway, SKI2 and SKI3, function as negative regulators of transgene PTGS in Arabidopsis. The ski2 mutants manifested severe synthetic phenotypes with a 5 -3 exoribonuclease mutant, ein5, which were substantially suppressed by the PTGS mutants, rdr6 and ago1. RDR6 is essential for the altered gene expression in ein5 ski2 on a transcriptome-wide scale. mRNA-seq approach was used to investigate the physiological relevance veiled by the myriad developmental phenotypes in Col-0 (C), ein5-1 (e), ski2-3 (s), ein5-1 ski2-3 (es), rdr6-11 (r) and rdr6-11 ein5-1 ski2-3 (res). A number of endogenous genes, including many miRNA target genes, manifest transitive 21-22 nt siRNA production and compromised gene expression in ein5 ski2 in an RDR6-dependent manner. Taken together, our study brings to light a dual-safeguard system in preventing the expansive siRNA production by the 5 -3 and 3 -5 cytoplasmic mRNA decay pathways. In this experiment, we did three replicates in sequencing that help increase the power in identify the differentially represented genes.The sequencing depth was also increased. Therefore we identified more siRNA-generating loci than that in previous study (GSE52408) (441 vs. 200 loci).
Project description:The hormone abscisic acid (ABA) regulates many plant stress responses and plant development by activating a complex gene regulatory network. This time series experiment was designed to unravel the architecture and dynamics of the ABA gene regulatory network.
Project description:Post-transcriptional gene silence (PTGS) is employed in plants to shut down transgenes, invading viral genes and a certain group of endogenous genes. Meanwhile, it is not clear how the risk of expansive PTGS from endogenous genes featured by transitive siRNA production is minimized. Here we demonstrate two essential components of the SKI complex in cytoplasmic 3 -5 mRNA decay pathway, SKI2 and SKI3, function as negative regulators of transgene PTGS in Arabidopsis. The ski2 mutants manifested severe synthetic phenotypes with a 5 -3 exoribonuclease mutant, ein5, which were substantially suppressed by the PTGS mutants, rdr6 and ago1. RDR6 is essential for the altered gene expression in ein5 ski2 on a transcriptome-wide scale. mRNA-seq approach was used to investigate the physiological relevance veiled by the myriad developmental phenotypes in Col-0 (C), ein5-1 (e), ski2-3 (s), ein5-1 ski2-3 (es), rdr6-11 (r) and rdr6-11 ein5-1 ski2-3 (res). A number of endogenous genes, including many miRNA target genes, manifest transitive 21-22 nt siRNA production and compromised gene expression in ein5 ski2 in an RDR6-dependent manner. Taken together, our study brings to light a dual-safeguard system in preventing the expansive siRNA production by the 5 -3 and 3 -5 cytoplasmic mRNA decay pathways. In this experiment, we did three replicates in sequencing that help increase the power in identify the differentially represented genes.The sequencing depth was also increased. Therefore we identified more siRNA-generating loci than that in previous study (GSE52408) (441 vs. 200 loci). Examination of small RNA profiles in 4 genotypes with 3 biological replicates each.
Project description:The hormone abscisic acid (ABA) regulates many plant stress responses and plant development by activating a complex gene regulatory network. This time series experiment was designed to unravel the architecture and dynamics of the ABA gene regulatory network.
Project description:Analyses of endogenous rna substrates of xrn and exosome and ptgs pathways Integrating RNA Quality Control and RNA Silencing Pathways
Project description:The signaling pathway of the phytohormone abscisic acid (ABA) regulates responses towards abiotic stress such as drought and high osmotic conditions. The multitude of functionally redundant components involved in ABA signaling, poses a major challenge for elucidating the largely unresolved response selectivity. We decided rebuilding single linear ABA signaling pathways in yeast for combinatoric permutation of ABA receptors and coreceptors, as well as the response-mediating SnRK2 protein kinases and their targeted transcription factors to drive luciferase expression in a heterologous host. We show that SnRK2s differ in the regulation by ABA receptor complexes, affect ABA responsiveness of the pathway, and differ in their transactivation activity but have similar preferences for ABA-responsive transcription factors. SnRK2s thought to act ABA-independently and known to be activated under osmotic stress in plants were regulated by ABA receptor complexes in yeast and competed with ABA receptor components in an ABA-dependent manner in plant tissue. The study reveals the suitability of the yeast system for analysis of ABA signaling factors and allowing the future dissection of ligand-receptor specificities in a functional response pathway. The analysis provides new insights into SnRK2 regulation indicating that four SnRK2 members of the osmotic stress response are tightly embedded into the ABA signaling pathway.