RDE-1 slicer activity is required only for passenger-strand cleavage during RNAi in Caenorhabditis elegans

Steiner, Florian; Okihara, Kristy L.; Hoogstrate, Suzanne W.; Sijen, Titia; Ketting, René F.

doi:10.1038/nsmb.1541

Cited by 73 publications

(66 citation statements)

References 37 publications

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“…Why do only some Argonaute proteins possess endonuclease activity, despite containing crucial conserved amino acids? Two recent publications have reported that Argonaute proteins might have different cleavage preferences: whereas only human AGO2 cleaves complementary target mRNAs through an RNAi-like mechanism, both AGO1 and AGO2 can cleave the passenger strand of an siRNA duplex (Steiner et al, 2009;Wang, B. et al, 2009). However, further work will be necessary to confirm these initial observations.…”

Section: Perspectivesmentioning

confidence: 99%

Argonaute proteins at a glance

Ender

Meister

2010

Journal of Cell Science

178

125

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Section: Perspectivesmentioning

confidence: 99%

Argonaute proteins at a glance

Ender

Meister

2010

Journal of Cell Science

178

125

View full text Add to dashboard Cite

“…Genetic studies indicate that antiviral RNAi in C. elegans requires the genes essential for RNAi induced by exogenous dsRNA (12)(13)(14)(15)(16)(17). These include Dicer-1 and dsRNA-binding protein RDE-4 (RNA interference-deficient 4), involved in the biogenesis of primary siRNAs predominantly 23 nt in length, and Argonaute protein RDE-1 (RNA interference-deficient 1) and RNA-dependent RNA polymerase RRF-1, required for the production of secondary siRNAs (18)(19)(20)(21)(22). Worm secondary siRNAs are 22-nt singlestranded RNAs with G as the 5′-terminal nt and antisense to the target mRNA, and are often referred as 22G RNAs (23)(24)(25).…”

mentioning

confidence: 99%

Homologous RIG-I–like helicase proteins direct RNAi-mediated antiviral immunity in C. elegans by distinct mechanisms

Guo

Zhang

Wang

et al. 2013

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

128

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RNAi-mediated antiviral immunity in Caenorhabditis elegans requires Dicer-related helicase 1 (DRH-1), which encodes the helicase and C-terminal domains homologous to the mammalian retinoic acid inducible gene I (RIG-I)-like helicase (RLH) family of cytosolic immune receptors. Here we show that the antiviral function of DRH-1 requires the RIG-I homologous domains as well as its wormspecific N-terminal domain. We also demonstrate that the helicase and C-terminal domains encoded by either worm DRH-2 or human RIG-I can functionally replace the corresponding domains of DRH-1 to mediate antiviral RNAi in C. elegans. Notably, substitutions in a three-residue motif of the C-terminal regulatory domain of RIG-I that physically interacts with viral double-stranded RNA abolish the antiviral activity of C-terminal regulatory domains of both RIG-I and DRH-1 in C. elegans. Genetic analysis revealed an essential role for both DRH-1 and DRH-3 in C. elegans antiviral RNAi targeting a natural viral pathogen. However, Northern blot and small RNA deep sequencing analyses indicate that DRH-1 acts to enhance production of viral primary siRNAs, whereas DRH-3 regulates antiviral RNAi by participating in the biogenesis of secondary siRNAs after Dicer-dependent production of primary siRNAs. We propose that DRH-1 facilitates the acquisition of viral double-stranded RNA by the worm dicing complex for the subsequent processing into primary siRNAs. The strong parallel for the antiviral function of RLHs in worms and mammals suggests that detection of viral doublestranded RNA may activate completely unrelated effector mechanisms or, alternatively, that the mammalian RLHs have a conserved activity to stimulate production of viral siRNAs for antiviral immunity by an RNAi effector mechanism.I nnate immunity refers to ancient host defense systems that act immediately after pathogen attack and are under the control of germline-encoded immune receptors. Pathogen sensing by several classes of immune receptors such as retinoic acid inducible gene I (RIG-I)-like cytosolic sensors in mammals leads to the transcriptional activation of effector genes in the nucleus (1). In contrast, detection of viral double-stranded RNA (dsRNA) by Dicer endonucleases is associated with the production of small interfering RNAs (siRNAs), which subsequently direct sequencespecific antiviral immunity through RNA interference (RNAi) (2-5). Antiviral RNAi is a major antiviral defense mechanism in fungi, plants, insects, and nematodes, so that suppression of the defense by a virus-encoded suppressor of RNAi is essential to establish infection (6-8). Although the RNAi machinery is highly conserved in mammals, conclusive evidence for a natural antiviral role of RNAi in mammals is not available (9).The nematode Caenorhabditis elegans has recently emerged as a small-animal model for innate immunity studies (10, 11). Genetic studies indicate that antiviral RNAi in C. elegans requires the genes essential for RNAi induced by exogenous dsRNA (12-17). These include Dicer-1 and dsRNA-bind...

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“…There are >20 C. elegans Argonaute proteins (Yigit et al 2006). Although RDE-1 possesses the DDH motif, the RNase H activity of RDE-1 is not required for triggering the silencing response at the target mRNA level (Steiner et al 2009). The secondary Argonautes (WAGOs) are required for silencing, but most of them lack the conserved DDH motif, suggesting that they may trigger target mRNA degradation by mechanisms other than RNase H-mediated cleavage (Yigit et al 2006).…”

mentioning

confidence: 99%

The RDE-10/RDE-11 complex triggers RNAi-induced mRNA degradation by association with target mRNA in C. elegans

Yang

Zhang²,

Vallandingham³

et al. 2012

Genes Dev.

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The molecular mechanisms for target mRNA degradation in Caenorhabditis elegans undergoing RNAi are not fully understood. Using a combination of genetic, proteomic, and biochemical approaches, we report a divergent RDE-10/RDE-11 complex that is required for RNAi in C. elegans. Genetic analysis indicates that the RDE-10/ RDE-11 complex acts in parallel to nuclear RNAi. Association of the complex with target mRNA is dependent on RDE-1 but not RRF-1, suggesting that target mRNA recognition depends on primary but not secondary siRNA. Furthermore, RDE-11 is required for mRNA degradation subsequent to target engagement. Deep sequencing reveals a fivefold decrease in secondary siRNA abundance in rde-10 and rde-11 mutant animals, while primary siRNA and microRNA biogenesis is normal. Therefore, the RDE-10/RDE-11 complex is critical for amplifying the exogenous RNAi response. Our work uncovers an essential output of the RNAi pathway in C. elegans.

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RDE-1 slicer activity is required only for passenger-strand cleavage during RNAi in Caenorhabditis elegans

Cited by 73 publications

References 37 publications

Argonaute proteins at a glance

Argonaute proteins at a glance

Homologous RIG-I–like helicase proteins direct RNAi-mediated antiviral immunity in C. elegans by distinct mechanisms

The RDE-10/RDE-11 complex triggers RNAi-induced mRNA degradation by association with target mRNA in C. elegans

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