Endoplasmic reticulum as a hub organizing the activities of microRNAs and a subset of endogenous siRNAs in Arabidopsis
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ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE82041 | GEO | 2016/12/23
SECONDARY ACCESSION(S): PRJNA323733
REPOSITORIES: GEO
Similar Datasets
Project description:The endoplasmic reticulum (ER) was implicated as the site of microRNA (miRNA)-mediated translation repression in plants. Here, we examined the ER- and rough ER-associated small RNAome, transcriptome and translatome. We found that almost all cellular transcripts were present on membrane-bound polysomes (MBPs), and miRNAs were enriched in membranes and on MBPs. miRNAs were recruited to membranes by their effector protein AGO1, whereas AGO1 associated with membranes and, partly ribosomes, in an RNA-independent manner. Most strikingly, 22 ntmiRNA isoformsand a set of 22 ntsiRNAs, were enriched in the membrane fraction and onMBPs, where they trigger phasedsecondary siRNAproduction from target transcripts. Loss of membrane association of the 22 nt small RNAs resulted in the loss of phasing in secondary siRNA production.These findings point to the ER as a hub that hosts and organizes endogenous small RNAs in plants.
2016-12-23 | GSE82040 | GEO
Project description:The endoplasmic reticulum (ER) was implicated as the site of microRNA (miRNA)-mediated translation repression in plants. Here, we examined the ER- and rough ER-associated small RNAome, transcriptome and translatome. We found that almost all cellular transcripts were present on membrane-bound polysomes (MBPs), and miRNAs were enriched in membranes and on MBPs. miRNAs were recruited to membranes by their effector protein AGO1, whereas AGO1 associated with membranes and, partly ribosomes, in an RNA-independent manner. Most strikingly, 22 ntmiRNA isoformsand a set of 22 ntsiRNAs, were enriched in the membrane fraction and onMBPs, where they trigger phasedsecondary siRNAproduction from target transcripts. Loss of membrane association of the 22 nt small RNAs resulted in the loss of phasing in secondary siRNA production.These findings point to the ER as a hub that hosts and organizes endogenous small RNAs in plants.
2016-12-23 | GSE82039 | GEO
Project description:Endoplasmic reticulum (ER) was implicated as the site of microRNA (miRNA)-mediated translational repression in plants. Here, we examined the ER- and rough ER- associated small RNAome, transcriptome and translatome. We found that nearly all cellular transcripts were present on membrane-bound polysomes (MBPs), and miRNAs and a small set of endogenous siRNAs were particularly enriched on MBPs. The MBP- enriched miRNAs and siRNAs associated with, and were recruited to membranes by, their effector protein ARGONAUTE1 (AGO1). AGO1 associated with ER in a partly RNA-independent manner. Reduced membrane association of 22-nt miRNAs, which trigger the biogenesis of phased, secondary siRNAs (phasiRNAs) from their target transcripts, was accompanied by decreased production or loss of phasing of phasiRNAs. The phasiRNA precursor transcripts, previously thought to be noncoding, were associated with MBPs in a manner that supported phasiRNA production. These findings point to the ER as a hub that hosts and organizes endogenous small RNAs in plants.
2016-12-27 | GSE92922 | GEO
Project description:Endoplasmic reticulum as a hub organizing the activities of microRNAs and a subset of endogenous siRNAs in Arabidopsis
| PRJNA323733 | ENA
Project description:Translation inhibition is a major but poorly understood mode of action of microRNAs (miRNAs) in plants and animals. In particular, the subcellular location where this process takes place is unknown. Here, we show that the translation inhibition, but not the mRNA cleavage activity, of Arabidopsis miRNAs requires ALTERED MERISTEM PROGRAM1 (AMP1). AMP1 encodes an integral membrane protein associated with endoplasmic reticulum (ER) and ARGONAUTE1, the miRNA effector and a peripheral ER membrane protein. Large differences in polysome association of miRNA target RNAs are found between wild-type and the amp1 mutant for membrane-bound, but not total, polysomes. This, together with AMP1-independent recruitment of miRNA target transcripts to membrane fractions, shows that miRNAs inhibit the translation of target RNAs on the ER. This study demonstrates that translation inhibition is an important activity of plant miRNAs, reveals the subcellular location of this activity, and uncovers a previously unknown function of the ER.
| S-EPMC3694718 | biostudies-literature
Project description:Vertebrate mRNAs are frequently targeted for post-transcriptional repression by microRNAs (miRNAs) through mechanisms involving pairing of 3' UTR seed matches to bases at the 5' end of miRNAs. Through analysis of expression array data following miRNA or siRNA overexpression or inhibition, we found that mRNA fold change increases multiplicatively (i.e., log-additively) with seed match count and that a single 8 mer seed match mediates down-regulation comparable to two 7 mer seed matches. We identified several targeting determinants that enhance seed match-associated mRNA repression, including the presence of adenosine opposite miRNA base 1 and of adenosine or uridine opposite miRNA base 9, independent of complementarity to the siRNA/miRNA. Increased sequence conservation in the approximately 50 bases 5' and 3' of the seed match and increased AU content 3' of the seed match were each independently associated with increased mRNA down-regulation. All of these determinants are enriched in the vicinity of conserved miRNA seed matches, supporting their activity in endogenous miRNA targeting. Together, our results enable improved siRNA off-target prediction, allow integrated ranking of conserved and nonconserved miRNA targets, and show that targeting by endogenous and exogenous miRNAs/siRNAs involves similar or identical determinants.
| S-EPMC2040081 | biostudies-literature
Project description:Noncanonical microRNAs (miRNAs) and endogenous small interfering RNAs (endo-siRNAs) are key gene regulators in eukaryotes. Noncanonical miRNAs, which bypass part of the canonical miRNA biogenesis pathway, can originate from a variety of genomic loci, which include small nucleolar RNAs (snoRNAs), transfer RNAs (tRNAs) and introns, whereas endo-siRNAs can arise from repetitive elements, some of which are transposable. The roles of noncanonical miRNAs and endo-siRNAs in complex diseases have yet to be characterized. To investigate their potential expression and function in psoriasis, we carried out a comprehensive, genome-wide search for noncanonical miRNAs and endo-siRNAs in small RNA deep-sequencing data sets from normal and psoriatic human skin. By analyzing more than 670 million qualified reads from 67 small RNA libraries, we identified 21 novel, noncanonical miRNAs (3 snoRNA-derived and 2 tRNA-derived miRNAs and 16 miRtrons) and 39 novel endo-siRNAs that were expressed in skin. The expression of four novel small RNAs was validated by qRT-PCR in human skin, and their Argonaute association was confirmed by co-immunoprecipitation of ectopic small RNAs in HEK293 cells. Fifteen noncanonical miRNAs or endo-siRNAs were significantly differentially expressed in psoriatic-involved versus normal skin, including an Alu-short interspersed element-derived siRNA which was 17-fold up-regulated in psoriatic-involved skin. These and other differentially expressed small noncoding RNAs may function as regulators of gene expression in skin and potentially play a role in psoriasis pathogenesis.
| S-EPMC3554200 | biostudies-literature
Project description:MicroRNA (miRNA) and endogenous small interfering RNA (endo-siRNA) are two essential classes of small noncoding RNAs (sncRNAs) in eukaryotes. The class of miRNA is diverse and there exist noncanonical miRNAs that bypass the canonical miRNA biogenesis pathway. In order to identify noncanonical miRNAs and endo-siRNAs responding to virus infection and study their potential function, we sequenced small-RNA species from cells lytically infected with murine gammaherpesvirus 68 (MHV68). In addition to three novel canonical miRNAs in mouse, two antisense miRNAs in virus and 25 novel noncanonical miRNAs, including miRNAs derived from transfer RNAs, small nucleolar RNAs and introns, in the host were identified. These noncanonical miRNAs exhibited features distinct from that of canonical miRNAs in lengths of hairpins, base pairings and first nucleotide preference. Many of the novel miRNAs are conserved in mammals. Besides several known murine endo-siRNAs detected by the sequencing profiling, a novel locus in the mouse genome was identified to produce endo-siRNAs. This novel endo-siRNA locus is comprised of two tandem inverted B4 short interspersed nuclear elements (SINEs). Unexpectedly, the SINE-derived endo-siRNAs were found in a variety of sequencing data and virus-infected cells. Moreover, a murine miRNA was up-regulated more than 35 fold in infected than in mock-treated cells. The putative targets of the viral and the up-regulated murine miRNAs were potentially involved in processes of gene transcription and protein phosphorylation, and localized to membranes, suggesting their potential role in manipulating the host basal immune system during lytic infection. Our results extended the number of noncanonical miRNAs in mammals and shed new light on their potential functions of lytic infection of MHV68.
| S-EPMC3482243 | biostudies-literature
Project description:BackgroundSmall endogenous non-coding RNAs (sncRNAs) such as small interfering RNA (siRNA), microRNA and other small RNA transcripts are derived from distinct loci in the genome and play critical roles in RNA-mediated gene silencing mechanisms in plants and metazoa. They are approximately 22 nucleotides long; regulate mRNA stability through perfect or imperfect match to the targets. The biological activities of sncRNAs have been related to many biological events, from resistance to microbe infections to cellular differentiation. The development of the zoonotic parasite Schistosoma japonicum parasite includes multiple steps of morphological alterations and biological differentiations, which provide a unique model for studies on the functions of small RNAs. Characterization of the genome-wide transcription of the sncRNAs will be a major step in understanding of the parasite biology. The objective of this study is to investigate the transcriptional profile and potential function of the small non-coding RNAs in the development of S. japanicum.ResultsThe endogenous siRNAs were found mainly derived from transposable elements (TE) or transposons and the natural antisense transcripts (NAT). In contrast to other organisms, the TE-derived siRNAs in S. japonicum were more predominant than other sncRNAs including microRNAs (miRNAs). Further, there were distinct length and 3'end variations in the sncRNAs, which were associated with the developmental differentiation of the parasite. Among the identified miRNA transcripts, there were 38 unique to S. japonicum and 16 that belonged to 13 miRNA families are common to other metazoan lineages. These miRNAs were either ubiquitously expressed, or they exhibited specific expression patterns related to the developmental stages or sex. Genes that encoded miRNAs are mainly located in clusters within the genome of S. japonicum. However, genes within one cluster could be differentially transcribed, which suggested that individual genes might be regulated by distinct mechanisms during parasite development.ConclusionsMany miRNA and endogenous siRNA transcripts were identified in S. japonicum and the amount of siRNA was at least 4.4 and 1.6 times more than that of miRNA in both schistosomulum and adult worm stages respectively. SiRNAs are mainly derived from transposable elements (or transposons); while natural antisense transcripts (NAT)-derived siRNAs were much less. A majority of miRNA transcripts identified in the parasite were species-specific and the expression of certain miRNAs was found developmentally regulated. Both miRNA and siRNAs are potentially important regulators in the development of schistosomal parasites.
| S-EPMC2820009 | biostudies-literature
Project description:Endoplasmic reticulum-associated degradation (ERAD) represents a principle quality control (QC) mechanism to clear misfolded proteins in the ER; however, its physiological significance and the nature of endogenous ERAD substrates remain largely unknown. Here we discover that IRE1alpha, the sensor of unfolded protein response (UPR), is a bona fide substrate of the Sel1L-Hrd1 ERAD complex. Mechanistically, ERAD-mediated IRE1alpha degradation occurs in a Bip-dependent manner under basal conditions and is attenuated in response to ER stress. Both intramembrane hydrophilic residues of IRE1alpha and lectin protein OS9 are required for IRE1alpha degradation. ERAD deficiency causes IRE1alpha protein stabilization, accumulation and mild activation both in vitro and in vivo, leading to cellular hypersensitivity to ER stress and inflammation. Furthermore, though enterocyte-specific Sel1L-knockout mice (Sel1LÎ?IEC) are viable and appear normal, they are more susceptible to experimental colitis in an IRE1alpha-dependent but CHOP-independent manner. Collectively, these results demonstrate that Sel1L-Hrd1 ERAD serves a distinct, essential function in restraint of IRE1alpha signaling in vivo by managing its protein turnover. Colon epithelium of wild type and enterocyte-specific Sel1L knockout mice were subjected to gene expression analysis.
2015-11-04 | E-GEOD-70563 | biostudies-arrayexpress