An Ascovirus-Encoded RNase III Autoregulates Its Expression and Suppresses RNA Interference-Mediated Gene Silencing

Hussain, Mazhar; Abraham, Alexander M.; Asgari, Sassan

doi:10.1128/jvi.02362-09

Cited by 44 publications

(55 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For the most part, these VSRs are structurally unrelated to each other, and antagonize antiviral RNAi at multiple levels, either binding, sequestering, and degrading long dsRNAs or siRNA duplexes or antagonizing the catalytic activity of AGO2 (20,21,(23)(24)(25)(26). Extensive characterization of the Lepidopteran large DNA viruses has identified a range of VSAs, targeting another prominent antiviral pathway.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Cytokine Diedel and a viral homologue suppress the IMD pathway in Drosophila

Lamiable

Kellenberger

Kemp

et al. 2016

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

111

View full text Add to dashboard Cite

Viruses are obligatory intracellular parasites that suffer strong evolutionary pressure from the host immune system. Rapidly evolving viral genomes can adapt to this pressure by acquiring genes that counteract host defense mechanisms. For example, many vertebrate DNA viruses have hijacked cellular genes encoding cytokines or cytokine receptors to disrupt host cell communication. Insect viruses express suppressors of RNA interference or apoptosis, highlighting the importance of these cell intrinsic antiviral mechanisms in invertebrates. Here, we report the identification and characterization of a family of proteins encoded by insect DNA viruses that are homologous to a 12-kDa circulating protein encoded by the virus-induced Drosophila gene diedel (die). We show that die mutant flies have shortened lifespan and succumb more rapidly than controls when infected with Sindbis virus. This reduced viability is associated with deregulated activation of the immune deficiency (IMD) pathway of host defense and can be rescued by mutations in the genes encoding the homolog of IKKγ or IMD itself. Our results reveal an endogenous pathway that is exploited by insect viruses to modulate NF-κB signaling and promote fly survival during the antiviral response.

show abstract

Section: Resultsmentioning

confidence: 99%

“…inhibitors of RNAi or apoptosis (known as VSRs or VSAs, for viral suppressors of RNAi or apotosis, respectively), attesting to the restrictive pressures exerted by these host antiviral mechanisms in insects (20)(21)(22)(23)(24)(25)(26).…”

Section: Significancementioning

confidence: 99%

Cytokine Diedel and a viral homologue suppress the IMD pathway in Drosophila

Lamiable

Kellenberger

Kemp

et al. 2016

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

111

View full text Add to dashboard Cite

show abstract

“…In this case the build-up of an efficient antiviral silencing complex is prevented by endonuclease activity of RNase3 that cleaves the 21 À 24 nt vsiRNAs into 14 bp products rendering them inactive (Cuellar et al, 2009;Kreuze et al, 2005). Insect infecting Heliothis virescens ascovirus3e orf27 (RNase3 enzyme) suppressor works in analogous manner: it competes with Dcr-2 for dsRNAs and degrades dsRNAs and siRNAs (Hussain et al, 2010).…”

Section: Blocking Initiation Of Antiviral Responsementioning

confidence: 97%

viral silencing suppressors: Tools forged to fine-tune host-pathogen coexistence

2015

View full text Add to dashboard Cite

RNA silencing is a homology-dependent gene inactivation mechanism that regulates a wide range of biological processes including antiviral defense. To deal with host antiviral responses viruses evolved mechanisms to avoid or counteract this, most notably through expression of viral suppressors of RNA silencing. Besides working as silencing suppressors, these proteins may also fulfill other functions during infection. In many cases the interplay between the suppressor function and other "unrelated" functions remains elusive. We will present host factors implicated in antiviral pathways and summarize the current status of knowledge about the diverse viral suppressors' strategies acting at various steps of antiviral silencing in plants. Besides, we will consider the multi-functionality of these versatile proteins and related biochemical processes in which they may be involved in fine-tuning the plant-virus interaction. Finally, we will present the current applications and discuss perspectives of the use of these proteins in molecular biology and biotechnology.

show abstract

“…This pathway has been implicated as a mechanism of defense against invasive nucleic acids from viruses or from mobile genetic elements, and has been conclusively shown to regulate gene expression in virtually all eukaryotic organisms (Fire, 2007;Hussain et al, 2010;Huvenne and Smagghe, 2010;Scott et al, 2013;Terenius et al, 2011).…”

Section: Introductionmentioning

confidence: 99%