The importance of innate immunity to rotaviruses is exemplified by the range of strategies evolved by rotaviruses to interfere with the IFN response. We showed previously that rotaviruses block gene expression induced by type I and II IFNs, through a mechanism allowing activation of signal transducer and activator of transcription (STAT) 1 and STAT2 but preventing their nuclear accumulation. This normally occurs through activated STAT1/2 dimerization, enabling an interaction with importin α5 that mediates transport into the nucleus. In rotavirus-infected cells, STAT1/2 inhibition may limit the antiviral actions of IFN produced early in infection. Here we further analysed the block to STAT1/2 nuclear accumulation, showing that activated STAT1 accumulates in the cytoplasm in rotavirus-infected cells. STAT1/2 nuclear accumulation was inhibited by rotavirus even in the presence of the nuclear export inhibitor Leptomycin B, demonstrating that enhanced nuclear export is not involved in STAT1/2 cytoplasmic retention. The ability to inhibit STAT nuclear translocation was completely conserved amongst the group A rotaviruses tested, including a divergent avian strain. Analysis of mutant rotaviruses indicated that residues after amino acid 47 of NSP1 are dispensable for STAT inhibition. Furthermore, expression of any of the 12 Rhesus monkey rotavirus proteins did not inhibit IFN-stimulated STAT1 nuclear translocation. Finally, co-immunoprecipitation experiments from transfected epithelial cells showed that STAT1/2 binds importin α5 normally following rotavirus infection. These findings demonstrate that rotavirus probably employs a novel strategy to inhibit IFN-induced STAT signalling, which acts after STAT activation and binding to the nuclear import machinery.
ArnoldM. M., BarroM., PattonJ. T.2013a; Rotavirus NSP1 mediates degradation of interferon regulatory factors through targeting of the dimerization domain. J Virol 87:9813–9821 [View Article][PubMed]
ArnoldM. M., SenA., GreenbergH. B., PattonJ. T.2013b; The battle between rotavirus and its host for control of the interferon signaling pathway. PLoS Pathog 9:e1003064 [View Article][PubMed]
BarroM., PattonJ. T.2005; Rotavirus nonstructural protein 1 subverts innate immune response by inducing degradation of IFN regulatory factor 3. Proc Natl Acad Sci U S A 102:4114–4119 [View Article][PubMed]
BarroM., PattonJ. T.2007; Rotavirus NSP1 inhibits expression of type I interferon by antagonizing the function of interferon regulatory factors IRF3, IRF5, and IRF7. J Virol 81:4473–4481 [View Article][PubMed]
ChenW., CalvoP. A., MalideD., GibbsJ., SchubertU., BacikI., BastaS., O’NeillR., SchickliJ.other authors2001; A novel influenza A virus mitochondrial protein that induces cell death. Nat Med 7:1306–1312 [View Article][PubMed]
CoulsonB. S., TursiJ. M., McAdamW. J., BishopR. F.1986; Derivation of neutralizing monoclonal antibodies to human rotaviruses and evidence that an immunodominant neutralization site is shared between serotypes 1 and 3. Virology 154:302–312 [View Article][PubMed]
CoulsonB. S., UnicombL. E., PitsonG. A., BishopR. F.1987; Simple and specific enzyme immunoassay using monoclonal antibodies for serotyping human rotaviruses. J Clin Microbiol 25:509–515[PubMed]
GraffJ. W., EwenJ., EttayebiK., HardyM. E.2007; Zinc-binding domain of rotavirus NSP1 is required for proteasome-dependent degradation of IRF3 and autoregulatory NSP1 stability. J Gen Virol 88:613–620 [View Article][PubMed]
GrahamK. L., HalaszP., TanY., HewishM. J., TakadaY., MackowE. R., RobinsonM. K., CoulsonB. S.2003; Integrin-using rotaviruses bind α2β1 integrin α2 I domain via VP4 DGE sequence and recognize alphaXbeta2 and alphaVbeta3 by using VP7 during cell entry. J Virol 77:9969–9978 [View Article][PubMed]
HagmaierK., StockN., PreciousB., ChildsK., WangL. F., GoodbournS., RandallR. E.2007; Mapuera virus, a rubulavirus that inhibits interferon signalling in a wide variety of mammalian cells without degrading STATs. J Gen Virol 88:956–966 [View Article][PubMed]
HuangJ. A., NageshaH. S., SnodgrassD. R., HolmesI. H.1992; Molecular and serological analyses of two bovine rotaviruses (B-11 and B-60) causing calf scours in Australia. J Clin Microbiol 30:85–92[PubMed]
JaggerB. W., WiseH. M., KashJ. C., WaltersK. A., WillsN. M., XiaoY. L., DunfeeR. L., SchwartzmanL. M., OzinskyA.other authors2012; An overlapping protein-coding region in influenza A virus segment 3 modulates the host response. Science 337:199–204 [View Article][PubMed]
KoolD. A., MatsuiS. M., GreenbergH. B., HolmesI. H.1992; Isolation and characterization of a novel reassortant between avian Ty-1 and simian RRV rotaviruses. J Virol 66:6836–6839[PubMed]
LondriganS. L., HewishM. J., ThomsonM. J., SandersG. M., MustafaH., CoulsonB. S.2000; Growth of rotaviruses in continuous human and monkey cell lines that vary in their expression of integrins. J Gen Virol 81:2203–2213[PubMed]
McBrideK. M., McDonaldC., ReichN. C.2000; Nuclear export signal located within the DNA-binding domain of the STAT1 transcription factor. EMBO J 19:6196–6206 [View Article][PubMed]
MeyerT., MargA., LemkeP., WiesnerB., VinkemeierU.2003; DNA binding controls inactivation and nuclear accumulation of the transcription factor Stat1. Genes Dev 17:1992–2005 [View Article][PubMed]
RamachandranA., HorvathC. M.2009; Paramyxovirus disruption of interferon signal transduction: STATus report. J Interferon Cytokine Res 29:531–537 [View Article][PubMed]
RandallR. E., GoodbournS.2008; Interferons and viruses: an interplay between induction, signalling, antiviral responses and virus countermeasures. J Gen Virol 89:1–47 [View Article][PubMed]
SekimotoT., ImamotoN., NakajimaK., HiranoT., YonedaY.1997; Extracellular signal-dependent nuclear import of Stat1 is mediated by nuclear pore-targeting complex formation with NPI-1, but not Rch1. EMBO J 16:7067–7077 [View Article][PubMed]
StirzakerS. C., WhitfeldP. L., ChristieD. L., BellamyA. R., BothG. W.1987; Processing of rotavirus glycoprotein VP7: implications for the retention of the protein in the endoplasmic reticulum. J Cell Biol 105:2897–2903 [View Article][PubMed]
TaniguchiK., KojimaK., UrasawaS.1996; Nondefective rotavirus mutants with an NSP1 gene which has a deletion of 500 nucleotides, including a cysteine-rich zinc finger motif-encoding region (nucleotides 156 to 248), or which has a nonsense codon at nucleotides 153–155. J Virol 70:4125–4130[PubMed]
Torres-VegaM. A., GonzálezR. A., DuarteM., PoncetD., LópezS., AriasC. F.2000; The C-terminal domain of rotavirus NSP5 is essential for its multimerization, hyperphosphorylation and interaction with NSP6. J Gen Virol 81:821–830[PubMed]
TrojnarE., OttoP., JohneR.2009; The first complete genome sequence of a chicken group A rotavirus indicates independent evolution of mammalian and avian strains. Virology 386:325–333 [View Article][PubMed]
VidyA., El BougriniJ., Chelbi-AlixM. K., BlondelD.2007; The nucleocytoplasmic rabies virus P protein counteracts interferon signaling by inhibiting both nuclear accumulation and DNA binding of STAT1. J Virol 81:4255–4263 [View Article][PubMed]