Inducible Systemic RNA Silencing in<i>Caenorhabditis elegans</i>

Timmons, Lisa; Tabara, Hiroaki; Mello, Craig C.; Fire, Andrew

doi:10.1091/mbc.e03-01-0858

Cited by 135 publications

(116 citation statements)

References 61 publications

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“…Parent (P0) and progeny (F1) RNAi experiments (Table S3) were performed using RNAi E. coli clones for endogenous genes from the Ahringer library (55). Feeding RNAi and soaking animals in gfp-dsRNA are expected to cause similar silencing (56). RNAi clones and bacteria expressing gfp-dsRNA provided by the Hamza laboratory, University of Maryland, College Park, MD.…”

Section: Methodsmentioning

confidence: 99%

Extracellular RNA is transported from one generation to the next in Caenorhabditis elegans

Marre

Traver

Jose

2016

Proc. Natl. Acad. Sci. U.S.A.

110

144

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Experiences during the lifetime of an animal have been proposed to have consequences for subsequent generations. Although it is unclear how such intergenerational transfer of information occurs, RNAs found extracellularly in animals are candidate molecules that can transfer gene-specific regulatory information from one generation to the next because they can enter cells and regulate gene expression. In support of this idea, when double-stranded RNA (dsRNA) is introduced into some animals, the dsRNA can silence genes of matching sequence and the silencing can persist in progeny. Such persistent gene silencing is thought to result from sequencespecific interaction of the RNA within parents to generate chromatin modifications, DNA methylation, and/or secondary RNAs, which are then inherited by progeny. Here, we show that dsRNA can be directly transferred between generations in the worm Caenorhabditis elegans. Intergenerational transfer of dsRNA occurs even in animals that lack any DNA of matching sequence, and dsRNA that reaches progeny can spread between cells to cause gene silencing. Surprisingly, extracellular dsRNA can also reach progeny without entry into the cytosol, presumably within intracellular vesicles. Fluorescently labeled dsRNA is imported from extracellular space into oocytes along with yolk and accumulates in punctate structures within embryos. Subsequent entry into the cytosol of early embryos causes gene silencing in progeny. These results demonstrate the transport of extracellular RNA from one generation to the next to regulate gene expression in an animal and thus suggest a mechanism for the transmission of experience-dependent effects between generations.circulating RNA | parental RNAi | epigenetics | transgenerational inheritance | endocytosis

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Section: Methodsmentioning

confidence: 99%

Extracellular RNA is transported from one generation to the next in Caenorhabditis elegans

Marre

Traver

Jose

2016

Proc. Natl. Acad. Sci. U.S.A.

110

144

View full text Add to dashboard Cite

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“…It is unclear whether dsRNA enters cells through passive, non-specific mechanisms, or whether there is an active mechanism that controls entry. Genetic analysis to identify genes involved in systemic spread of dsRNA in C. elegans isolated several mutants unable to distribute an ingested dsRNA signal from the gut throughout the body 8,10,11 . One of these, SID-1 (also known as RSD-8) is a putative transmembrane protein required for systemic spread 8 .…”

Section: Introductionmentioning

confidence: 99%

The endocytic pathway mediates cell entry of dsRNA to induce RNAi silencing

et al. 2006

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Many metazoan cells can take up exogenous double-stranded (ds) RNA and use it to initiate an RNA silencing response, however, the mechanism for this uptake is ill-defined. Here, we identify the pathway for dsRNA uptake in Drosophila melanogaster S2 cells. Biochemical and cell biological analyses, and a genome-wide screen for components of the dsRNA-uptake machinery, indicated that dsRNA is taken up by an active process involving receptor-mediated endocytosis. Pharmacological inhibition of endocytic pathways disrupted exogenous dsRNA entry and the induction of gene silencing. This dsRNA uptake mechanism seems to be evolutionarily conserved, as knockdown of orthologues in Caenorhabditis elegans inactivated the RNA interference response in worms. Thus, this entry pathway is required for systemic RNA silencing in whole organisms. In Drosophila cells, pharmacological evidence suggests that dsRNA entry is mediated by pattern-recognition receptors. The possible role of these receptors in dsRNA entry may link RNA interference (RNAi) silencing to other innate immune responses.RNAi is a highly conserved dsRNA-guided mechanism that mediates sequence-specific gene silencing 1 . A number of animal cells can naturally take up exogenous dsRNA and use it to initiate RNAi silencing 2,3 . In some organisms, such as Drosophila, certain cells can efficiently take up dsRNA but seem to be unable to transmit this dsRNA to other cells in the body 4 . dsRNA uptake without further transmission to other cells has also been reported for some mammalian cell types [5][6][7] . Other organisms (such as C. elegans or juvenile grasshoppers) can both take up dsRNA and spread it systemically to elicit an RNAi response throughout the entire animal 8,9 . The mechanisms of uptake and spread of dsRNA are poorly understood. It is unclear whether dsRNA enters cells through passive, non-specific mechanisms, or whether there is an active mechanism that controls entry. Genetic analysis to identify genes involved in systemic spread of dsRNA in C. elegans isolated several mutants unable to distribute an ingested dsRNA signal from the gut throughout the body 8,10,11 . One of these, SID-1 (also known as RSD-8) is a putative transmembrane protein required for systemic spread 8 . When expressed ectopically in Drosophila cells, SID-1 enhanced the RNAi response observed at low dsRNA 5Correspondence should be addressed to R.A. (e-mail: Raul.Andino@UCSF.edu). 3 Current address: Canada Research Chair in Innate Immunity, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Canada 4 These authors contributed equally to this work.Note: Supplementary Information is available on the Nature Cell Biology website. COMPETING FINANCIAL INTERESTSThe authors declare that they have no competing financial interests. concentrations 12 , raising the possibility that SID-1 may function as a channel on the cell surface for uptake of dsRNA. However, endogenous sid-1 homologues have not been found in the Drosophila genome, yet Drosophila S2 cells...

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“…The former ORF was sequenced and inserted appropriately into the L4440 double promoter vector (Timmons et al, 2003) to generate a apy-1 double-strand RNA (dsRNA) expression plasmid (L4440-apy-1) for RNAi assays and into the plasmid pRS426 (Mumberg et al, 1995) to obtain p426-apy-1 for heterologous expression into yeast gda1 mutant cells.…”

Section: Characterization and Heterologous Expression Of Apy-1mentioning

confidence: 99%

APY-1, a NovelCaenorhabditis elegansApyrase Involved in Unfolded Protein Response Signalling and Stress Responses

Uccelletti

Pascoli

Farina

et al. 2008

MBoC

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Protein glycosylation modulates a wide variety of intracellular events and dysfunction of the glycosylation pathway has been reported in a variety of human pathologies. Endo-apyrases have been suggested to have critical roles in protein glycosylation and sugar metabolism. However, deciphering the physiological relevance of Endo-apyrases activity has actually proved difficult, owing to their complexity and the functional redundancy within the family. We report here that a UDP/GDPase, homologous to the human apyrase Scan-1, is present in the membranes of Caenorhabditis elegans, encoded by the ORF F08C6.6 and hereinafter-named APY-1. We showed that ER stress induced by tunicamycin or high temperature resulted in increased transcription of apy-1. This increase was not observed in C. elegans mutants defective in ire-1 or atf-6, demonstrating the requirement of both ER stress sensors for up-regulation of apy-1. Depletion of APY-1 resulted in constitutively activated unfolded protein response. Defects in the pharynx and impaired organization of thin fibers in muscle cells were observed in adult worms depleted of APY-1. Some of the apy-1(RNAi) phenotypes are suggestive of premature aging, because these animals also showed accumulation of lipofuscin and reduced lifespan that was not dependent on the functioning of DAF-2, the receptor of the insulin/IGF-1 signaling pathway. INTRODUCTIONFrom observations on human diseases and mutant mice, it has become clear that glycosylation plays a major role in metazoan development (Schachter, 2004). Given the numerous physiological roles of glycoproteins, which encompass many aspects of normal cellular function and survival, the structures of glycan moieties vary markedly providing the chemical diversity required to fulfill the vast range of their biological tasks. The diversity of natural sugar structures is ultimately derived from the activities of the enzymes responsible for sugar attachment, namely glycosyltransferases, which determine the feasibility of natural product enzymatic glycodiversification. Lumenal ecto-nucleoside triand diphosphohydrolases (E-NTPDases) of the secretory pathway of eukaryotes hydrolyzes the nucleoside diphosphates (NDPs) generated by glycosyltransferases. The resulting nucleoside monophosphates (NMPs) are weaker inhibitors of glycosyltransferases than NDPs. NMPs also serve as antiporters in the transport of nucleotide-sugars from the cytosol to the lumen of the endoplasmic reticulum (ER) and Golgi apparatus. Glycosylation plays an important role in the biogenesis of secreted and transmembrane proteins and an elaborate mechanism ensure that only properly folded and assembled proteins exit the ER, a process termed "quality control."However, The ER's capacity to process proteins is relatively limited and the stress caused by accumulation of unfolded and misfolded proteins (ER stress) contributes to a number of important human diseases (Zhang and Kaufman, 2006). Cells respond to ER stress by activating the unfolded protein response (UPR), which limits new pr...

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Inducible Systemic RNA Silencing inCaenorhabditis elegans

Cited by 135 publications

References 61 publications

Extracellular RNA is transported from one generation to the next in Caenorhabditis elegans

Extracellular RNA is transported from one generation to the next in Caenorhabditis elegans

The endocytic pathway mediates cell entry of dsRNA to induce RNAi silencing

APY-1, a NovelCaenorhabditis elegansApyrase Involved in Unfolded Protein Response Signalling and Stress Responses

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