Fertile Hypomorphic <i>ARGONAUTE</i> (<i>ago1</i>) Mutants Impaired in Post-Transcriptional Gene Silencing and Virus Resistance

Morel, Jean-Benoît; Godon, Christian; Mourrain, Philippe; Béclin, Christophe; Boutet, Stéphanie; Feuerbach, Frank; Proux, Florence; Vaucheret, Hervé

doi:10.1105/tpc.010358

Cited by 588 publications

(592 citation statements)

References 42 publications

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“…For example, mutations in DDM1, MET1, NRPD1a, and RDR2 have a strong impact on TGS and a weak impact on PTGS (Morel et al 2000;Herr et al 2005). Reciprocally, AGO1 has a strong impact on PTGS and a weak impact on the taming of some transposons by TGS (Morel et al 2002;Lippman et al 2003). These results suggest that dsRNA-mediated TGS and PTGS likely result from the diversiWcation of an ancient common mechanism.…”

Section: Introductionmentioning

confidence: 93%

A single transgene locus triggers both transcriptional and post-transcriptional silencing through double-stranded RNA production

Mourrain

Blokland

Kooter

et al. 2006

Planta

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Silencing of a target locus by an unlinked silencing locus can result from transcription inhibition (transcriptional gene silencing; TGS) or mRNA degradation (post-transcriptional gene silencing; PTGS), owing to the production of double-stranded RNA (dsRNA) corresponding to promoter or transcribed sequences, respectively. The involvement of distinct cellular components in each process suggests that dsRNA-induced TGS and PTGS likely result from the diversiWcation of an ancient common mechanism. However, a strict comparison of TGS and PTGS has been diYcult to achieve because it generally relies on the analysis of distinct silencing loci. We describe a single transgene locus that triggers both TGS and PTGS, owing to the production of dsRNA corresponding to promoter and transcribed sequences of diVerent target genes. We describe mutants and epigenetic variants derived from this locus and propose a model for the production of dsRNA. Also, we show that PTGS, but not TGS, is graft-transmissible, which together with the sensitivity of PTGS, but not TGS, to RNA viruses that replicate in the cytoplasm, suggest that the nuclear compartmentalization of TGS is responsible for cell-autonomy. In contrast, we contribute local and systemic traYcking of silencing signals and sensitivity to viruses to the cytoplasmic steps of PTGS and to ampliWcation steps that require high levels of target mRNAs.

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Section: Introductionmentioning

confidence: 93%

A single transgene locus triggers both transcriptional and post-transcriptional silencing through double-stranded RNA production

Mourrain

Blokland

Kooter

et al. 2006

Planta

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“…Interestingly, the emu mutation enhanced the slightly altered phyllotaxy of ago1-27 inflorescences, wherein the internode length is more random than that in wild-type plants, resulting in multiple fruits emanating from the same node ( Fig. 4O,P ;Morel et al 2002;Smith et al 2009). Taken together, these data suggest that EMU may be involved in assuring proper miRNA action.…”

Section: Genetic Interactions Between Emu and Mirna Mutantsmentioning

confidence: 99%

Characterization of EMU, the Arabidopsis homolog of the yeast THO complex member HPR1

Furumizu¹,

Tsukaya²,

Komeda³

2010

RNA

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Diverse and precise control is essential for eukaryotic gene expression. This is accomplished through the recruitment of a myriad of proteins to a nascent messenger RNA (mRNA) to mediate modifications, such as capping, splicing, 39-end processing, and export. Despite being important for every cell, however, the mechanism by which the formation of diverse messenger ribonucleoprotein (mRNP) particles contributes to maintaining intricate systems in the multicellular organism remains incompletely defined. We identified and characterized a mutant gene named erecta mRNA under-expressed (emu) that leads to the defective mRNA accumulation of ERECTA, a developmental regulator in the model plant Arabidopsis thaliana. EMU encodes a protein homologous to a component of the THO complex that is required for the generation of functional mRNPs. Further analysis suggested that EMU is genetically associated with SERRATE, HYPONASTIC LEAVES1, and ARGONAUTE1, which are required for proper RNA maturation or action. Furthermore, mutations in another THO-related gene led to embryonic lethality. These findings support the presence and importance of the THO-related complex in plants as well as yeast and vertebrates.

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“…For example, Arabidopsis thaliana contains the genes SGS2/SDE1, SGS3, SDE3 and AGO1, which are all involved in RNA silencing [128]. Arabidopsis mutants defective in any of these genes were hypersensitive to CMV (Cucumber mosaic virus), but were equally susceptible to five other viruses as non-mutant plants [10,31,40,107]. However, tobacco and Arabidopsis plants mutant for a gene related to SGS2/SDE1, which, unlike SGS2/SDE1, is induced by viral infection, were more susceptible to both tobacco mosaic virus and PVX [3,40,138,140].…”

Section: Function In Plant Immune Systemsmentioning

confidence: 99%

Diversity, evolution, and therapeutic applications of small RNAs in prokaryotic and eukaryotic immune systems

Cooper

Overstreet

2014

Physics of Life Reviews

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Recent evidence supports that prokaryotes exhibit adaptive immunity in the form of CRISPR (Clustered Regularly Interspersed Short Palindromic Repeats) and Cas (CRISPR associated proteins). The CRISPR-Cas system confers resistance to exogenous genetic elements such as phages and plasmids by allowing for the recognition and silencing of these genetic elements. Moreover, CRISPR-Cas serves as a memory of past exposures. This suggests that the evolution of the immune system has counterparts among the prokaryotes, not exclusively among eukaryotes. Mathematical models have been proposed which simulate the evolutionary patterns of CRISPR, however large gaps in our understanding of CRISPR-Cas function and evolution still exist. The CRISPR-Cas system is analogous to small RNAs involved in resistance mechanisms throughout the tree of life, and a deeper understanding of the evolution of small RNA pathways is necessary before the relationship between these convergent systems is to be determined. Presented in this review are novel RNAi therapies based on CRISPR-Cas analogs and the potential for future therapies based on CRISPR-Cas system components.

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Fertile Hypomorphic ARGONAUTE (ago1) Mutants Impaired in Post-Transcriptional Gene Silencing and Virus Resistance

Cited by 588 publications

References 42 publications

A single transgene locus triggers both transcriptional and post-transcriptional silencing through double-stranded RNA production

A single transgene locus triggers both transcriptional and post-transcriptional silencing through double-stranded RNA production

Characterization of EMU, the Arabidopsis homolog of the yeast THO complex member HPR1

Diversity, evolution, and therapeutic applications of small RNAs in prokaryotic and eukaryotic immune systems

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