Viral protein inhibits RISC activity by argonaute binding through conserved WG/GW motifs.
RNA silencing is an evolutionarily conserved sequence-specific gene-inactivation system that also functions as an antiviral mechanism in higher plants and insects. To overcome antiviral RNA silencing, viruses express silencing-suppressor proteins. These viral proteins can target one or more key poin...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2010-01-01
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| Series: | PLoS Pathogens |
| Online Access: | http://europepmc.org/articles/PMC2904775?pdf=render |
| _version_ | 1818556398569521152 |
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| author | Ana Giner Lóránt Lakatos Meritxell García-Chapa Juan José López-Moya József Burgyán |
| author_facet | Ana Giner Lóránt Lakatos Meritxell García-Chapa Juan José López-Moya József Burgyán |
| author_sort | Ana Giner |
| collection | DOAJ |
| description | RNA silencing is an evolutionarily conserved sequence-specific gene-inactivation system that also functions as an antiviral mechanism in higher plants and insects. To overcome antiviral RNA silencing, viruses express silencing-suppressor proteins. These viral proteins can target one or more key points in the silencing machinery. Here we show that in Sweet potato mild mottle virus (SPMMV, type member of the Ipomovirus genus, family Potyviridae), the role of silencing suppressor is played by the P1 protein (the largest serine protease among all known potyvirids) despite the presence in its genome of an HC-Pro protein, which, in potyviruses, acts as the suppressor. Using in vivo studies we have demonstrated that SPMMV P1 inhibits si/miRNA-programmed RISC activity. Inhibition of RISC activity occurs by binding P1 to mature high molecular weight RISC, as we have shown by immunoprecipitation. Our results revealed that P1 targets Argonaute1 (AGO1), the catalytic unit of RISC, and that suppressor/binding activities are localized at the N-terminal half of P1. In this region three WG/GW motifs were found resembling the AGO-binding linear peptide motif conserved in metazoans and plants. Site-directed mutagenesis proved that these three motifs are absolutely required for both binding and suppression of AGO1 function. In contrast to other viral silencing suppressors analyzed so far P1 inhibits both existing and de novo formed AGO1 containing RISC complexes. Thus P1 represents a novel RNA silencing suppressor mechanism. The discovery of the molecular bases of P1 mediated silencing suppression may help to get better insight into the function and assembly of the poorly explored multiprotein containing RISC. |
| first_indexed | 2024-12-13T23:46:50Z |
| format | Article |
| id | doaj.art-edf47b20c2c649b09d127f272b3c0b27 |
| institution | Directory Open Access Journal |
| issn | 1553-7366 1553-7374 |
| language | English |
| last_indexed | 2024-12-13T23:46:50Z |
| publishDate | 2010-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS Pathogens |
| spelling | doaj.art-edf47b20c2c649b09d127f272b3c0b272022-12-21T23:26:56ZengPublic Library of Science (PLoS)PLoS Pathogens1553-73661553-73742010-01-0167e100099610.1371/journal.ppat.1000996Viral protein inhibits RISC activity by argonaute binding through conserved WG/GW motifs.Ana GinerLóránt LakatosMeritxell García-ChapaJuan José López-MoyaJózsef BurgyánRNA silencing is an evolutionarily conserved sequence-specific gene-inactivation system that also functions as an antiviral mechanism in higher plants and insects. To overcome antiviral RNA silencing, viruses express silencing-suppressor proteins. These viral proteins can target one or more key points in the silencing machinery. Here we show that in Sweet potato mild mottle virus (SPMMV, type member of the Ipomovirus genus, family Potyviridae), the role of silencing suppressor is played by the P1 protein (the largest serine protease among all known potyvirids) despite the presence in its genome of an HC-Pro protein, which, in potyviruses, acts as the suppressor. Using in vivo studies we have demonstrated that SPMMV P1 inhibits si/miRNA-programmed RISC activity. Inhibition of RISC activity occurs by binding P1 to mature high molecular weight RISC, as we have shown by immunoprecipitation. Our results revealed that P1 targets Argonaute1 (AGO1), the catalytic unit of RISC, and that suppressor/binding activities are localized at the N-terminal half of P1. In this region three WG/GW motifs were found resembling the AGO-binding linear peptide motif conserved in metazoans and plants. Site-directed mutagenesis proved that these three motifs are absolutely required for both binding and suppression of AGO1 function. In contrast to other viral silencing suppressors analyzed so far P1 inhibits both existing and de novo formed AGO1 containing RISC complexes. Thus P1 represents a novel RNA silencing suppressor mechanism. The discovery of the molecular bases of P1 mediated silencing suppression may help to get better insight into the function and assembly of the poorly explored multiprotein containing RISC.http://europepmc.org/articles/PMC2904775?pdf=render |
| spellingShingle | Ana Giner Lóránt Lakatos Meritxell García-Chapa Juan José López-Moya József Burgyán Viral protein inhibits RISC activity by argonaute binding through conserved WG/GW motifs. PLoS Pathogens |
| title | Viral protein inhibits RISC activity by argonaute binding through conserved WG/GW motifs. |
| title_full | Viral protein inhibits RISC activity by argonaute binding through conserved WG/GW motifs. |
| title_fullStr | Viral protein inhibits RISC activity by argonaute binding through conserved WG/GW motifs. |
| title_full_unstemmed | Viral protein inhibits RISC activity by argonaute binding through conserved WG/GW motifs. |
| title_short | Viral protein inhibits RISC activity by argonaute binding through conserved WG/GW motifs. |
| title_sort | viral protein inhibits risc activity by argonaute binding through conserved wg gw motifs |
| url | http://europepmc.org/articles/PMC2904775?pdf=render |
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