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PubMed2003

Two distinct mechanisms ensure transcriptional polarity in double-stranded RNA bacteriophages.

In most double-stranded RNA (dsRNA) viruses, RNA transcription occurs inside a polymerase (Pol) complex particle, which contains an RNA-dependent RNA Pol subunit as a minor component. Only plus- but not minus-sense copies of genomic segments are produced during this reaction. In the case of phi6, a dsRNA bacteriophage from the Cystoviridae family, isolated Pol synthesizes predominantly plus strands using virus-specific dsRNAs in vitro, thus suggesting that Pol template preferences determine the transcriptional polarity. Here, we dissect transcription reactions catalyzed by Pol complexes and Pol subunits of two other cystoviruses, phi8 and phi13. While both Pol complexes synthesize exclusively plus strands over a wide range of conditions, isolated Pol subunits can be stimulated by Mn(2+) to produce minus-sense copies on phi13 dsRNA templates. Importantly, all three Pol subunits become more prone to the native-like plus-strand synthesis when the dsRNA templates (including phi13 dsRNA) are activated by denaturation before the reaction. Based on these and earlier observations, we propose a model of transcriptional polarity in Cystoviridae controlled on two independent levels: Pol affinity to plus-strand initiation sites and accessibility of these sites to the Pol in a single-stranded form.

Bacteriophages↗
PubMed1971

Mechanism of reovirus double-stranded ribonucleic acid synthesis in vivo and in vitro.

The complementary strands of reovirus double-stranded ribonucleic acid (ds RNA) are synthesized sequentially in vivo and in vitro. In both cases, preformed plus strands serve as templates for the synthesis of the complementary minus strands. The in vitro synthesis of dsRNA is catalyzed by a large particulate fraction from reovirus-infected cells. Treatment of this fraction with chymotrypsin or with detergents which solubilize cellular membranes does not alter its capacity to synthesize dsRNA. The enzyme or enzymes responsible for dsRNA synthesis remain sedimentable at 10,000 x g after these enzyme or detergent treatments, indicating their particulate nature. Pretreatment of this fraction with ribonuclease, however, abolishes its ability to catalyze dsRNA synthesis, emphasizing the single-stranded nature of the template and its location in a structure permeable to ribonuclease. In contrast, the newly formed dsRNA is resistant to ribonuclease digestion at low salt concentrations and hence is thought to reside within a ribonuclease-impermeable structure.

Animals↗
PubMed1991

Functional expression and RNA binding analysis of the interferon-induced, double-stranded RNA-activated, 68,000-Mr protein kinase in a cell-free system.

Eukaryotic viruses have devised numerous strategies to downregulate activity of the interferon-induced, double-stranded (dsRNA)-activated protein kinase (referred to as p68 on the basis of its Mr of 68,000 in human cells). Viruses must exert this control to avoid extensive phosphorylation of the alpha subunit of eukaryotic initiation factor 2 (eIF-2) by p68 and the resultant negative effects on protein synthesis initiation. To begin to define the molecular mechanisms underlying this regulation, we optimized expression of p68 in an in vitro transcription-translation system utilizing the full-length cDNA clone. The in vitro-expressed kinase was autophosphorylated in response to dsRNAs and heparin in a manner similar to that for the native p68 provided that the kinase inhibitor, 2-aminopurine, was present during the in vitro translation reaction. Further, the activated kinase efficiently phosphorylated its natural substrate, the alpha subunit of eIF-2. Binding experiments revealed that the expressed kinase complexed with the dsRNA activator, reovirus dsRNA, as well as the adenovirus-encoded inhibitor, VAI RNA. Interestingly, both the reovirus RNAs and VAI RNA also complexed with protein kinase molecules that lacked the carboxyl terminus and all catalytic domains. Deletion analysis confirmed that the p68 amino terminus contained critical determinants for reovirus dsRNA and VAI RNA binding. Further, reovirus dsRNA efficiently bound to, but failed to activate, p68 kinase molecules containing a single amino acid substitution in the invariant lysine 295 present in catalytic domain II. Taken together, these data demonstrate that this expression system permits a detailed mutagenic analysis of the regions of p68 required for interaction with virus-encoded activators and repressors.

Adenoviridae↗
PubMed2004

Nucleocytoplasmic shuttling of JAZ, a new cargo protein for exportin-5.

Exportin-5 is a nuclear export receptor for certain classes of double-stranded RNA (dsRNA), including pre-micro-RNAs, viral hairpin RNAs, and some tRNAs. It can also export the RNA binding proteins ILF3 and elongation factor EF1A. However, the rules that determine which RNA binding proteins are exportin-5 cargoes remain unclear. JAZ possesses an unusual dsRNA binding domain consisting of multiple C2H2 zinc fingers. We found that JAZ binds to exportin-5 in a Ran-GTP- and dsRNA-dependent manner. Exportin-5 stimulates JAZ shuttling, and gene silencing of exportin-5 reduces shuttling. Recombinant exportin-5 also stimulates nuclear export of JAZ in permeabilized cells. JAZ also binds to ILF3, and surprisingly, this interaction is RNA independent, even though it requires the dsRNA binding domains of ILF3. Exportin-5, JAZ, and ILF3 can form a heteromeric complex with Ran-GTP and dsRNA, and JAZ increases ILF3 binding to exportin-5. JAZ does not contain a classical nuclear localization signal, and in digitonin-permeabilized cells, nuclear accumulation of JAZ does not require energy or cytosol. Nonetheless, low temperatures prevent JAZ import, suggesting that nuclear entry does not occur via simple diffusion. Together, these data suggest that JAZ is exported by exportin-5 but translocates back into nuclei by a facilitated diffusion mechanism.

Active Transport, Cell Nucleus↗
PubMed1988

Distinct binding sites for zinc and double-stranded RNA in the reovirus outer capsid protein sigma 3.

By atomic absorption analysis, we determined that the reovirus outer capsid protein sigma 3, which binds double-stranded RNA (dsRNA), is a zinc metalloprotein. Using Northwestern blots and a novel zinc blotting technique, we localized the zinc- and dsRNA-binding activities of sigma 3 to distinct V8 protease-generated fragments. Zinc-binding activity was contained within an amino-terminal fragment that contained a transcription factor IIIA-like zinc-binding sequence, and dsRNA-binding activity was associated with a carboxy-terminal fragment. By these techniques, new zinc- and dsRNA-binding activities were also detected in reovirus core proteins. A sequence similarity was observed between the catalytic site of the picornavirus proteases and the transcription factor IIIA-like zinc-binding site within sigma 3. We suggest that the zinc- and dsRNA-binding activities of sigma 3 may be important for its proposed regulatory effects on viral and host cell transcription and translation.

Amino Acid Sequence↗
PubMed1998

Antisense RNA: function and fate of duplex RNA in cells of higher eukaryotes.

There is ample evidence that cells of higher eukaryotes express double-stranded RNA molecules (dsRNAs) either naturally or as the result of viral infection or aberrant, bidirectional transcriptional readthrough. These duplex molecules can exist in either the cytoplasmic or nuclear compartments. Cells have evolved distinct ways of responding to dsRNAs, depending on the nature and location of the duplexes. Since dsRNA molecules are not thought to exist naturally within the cytoplasm, dsRNA in this compartment is most often associated with viral infections. Cells have evolved defensive strategies against such molecules, primarily involving the interferon response pathway. Nuclear dsRNA, however, does not induce interferons and may play an important posttranscriptional regulatory role. Nuclear dsRNA appears to be the substrate for enzymes which deaminate adenosine residues to inosine residues within the polynucleotide structure, resulting in partial or full unwinding. Extensively modified RNAs are either rapidly degraded or retained within the nucleus, whereas transcripts with few modifications may be transported to the cytoplasm, where they serve to produce altered proteins. This review summarizes our current knowledge about the function and fate of dsRNA in cells of higher eukaryotes and its potential manipulation as a research and therapeutic tool.

Animals↗
PubMed1978

Apparent absence of symmetrical transcription in Tetrahymena mitochondria.

Transcription in Tetrahymena pyriformis mitochondria has been examined for whether or not symmetrical transcription occurs. A ribonuclease A digestion in high-ionic strength was used as a test for the presence of double-stranded RNA (dsRNA) either before or after self-annealing. This test was applied to RNA prepared using pulse lengths of from 1 to 30 min. If symmetrical transcription occurred, then the amount of dsRNA should have varied inversely with pulse length. There was no evidence for the presence of dsRNA other than a ribonuclease-resistant core. A search was also made among the largest transcripts present (greater than 26S) since this region of a sucrose gradient is enriched in symmetrical transcripts in HeLa cells. Again none were found. In order to allow for possible rapid processing as the reason for the failure to find dsRNA, total cellular RNA was extracted as quickly as possible, and the ribonuclease digest analyzed by Sephadex chromatography. No large pieces of dsRNA were found.

Animals↗
PubMedDate not supplied

Two basic motifs of reovirus sigma 3 protein are involved in double-stranded RNA binding.

It has been reported that the sigma 3 protein of reovirus can exert an inhibitory effect on the cellular double-stranded RNA (dsRNA) activated protein kinase. Activation of this kinase is thought to be a general mechanism mediating a cellular antiviral response. This enzyme can also be activated upon transfection, resulting in translational inhibition of plasmid-encoded mRNAs. sigma 3 has an affinity for dsRNA postulated to be responsible for antikinase activity. In the present study, site-directed mutagenesis was performed on two basic regions previously suggested as dsRNA-binding motifs and the mutant sigma 3 proteins were then expressed in COS cells. These experiments revealed that both motifs are involved in sigma 3 attachment to RNA. Expression of the mutants lacking RNA-binding capability is stimulated by coexpression of another dsRNA-binding protein, the E3L vaccinia virus protein. These results support a model in which the attachment to dsRNA is directly responsible for the trans-stimulating effect of sigma 3 on expression of cotransfected genes.

Amino Acid Sequence↗
PubMed2004

Effects of double-stranded RNA in Metarhizium anisopliae var. acridum and Paecilomyces fumosoroseus on protease activities, conidia production, and virulence.

Isogenic strains (with and without dsRNA) of the entomogenous fungi Metarhizium anisopliae var. acridum and Paecilomyces fumosoroseus were investigated for correlation between the presence of dsRNA and the production of cuticle-degrading proteases that play an important role in host parasitism, total secreted protein, and conidia production. Similar levels of cuticle-degrading subtilisin-like (Pr1) protease were observed for isogenic strains of M. anisopliae var. acridum after growth in medium supplemented with the cuticle of the grasshopper Rhammatocerus schistocercoides. Similarly, no statistical differences were observed for protease production, detected using the chromogenic substrate azocasein. For P. fumosoroseus isogenic strains, no significant differences in protease activity were observed after growth in the presence of either Euschistus heros or Nezara viridula (Hemiptera: Pentatomidae) cuticle. Similarly, no statistical differences were observed in virulence against E. heros. A comparison of mean conidia production showed a significantly higher production in the dsRNA-free isogenic strains of M. anisopliae var. acridum. Although, for most of the fungal phenotypes analysed, no overt effects were associated with the presence of these dsRNA infections, the reduction in conidia production by the isogenic strains of M. anisopliae var. acridum with dsRNA suggested that it may not be entirely accurate to describe these infections as latent.

Animals↗
PubMed2002

Double-stranded RNA causes airway hyperreactivity and neuronal M2 muscarinic receptor dysfunction.

Viral infection causes dysfunction of inhibitory M2 muscarinic receptors (M2Rs) on parasympathetic nerves, leading to airway hyperreactivity. The mechanisms of M2R dysfunction are incompletely understood. Double-stranded RNA (dsRNA), a product of viral replication, promotes the expression of interferons. Interferon-gamma decreases M2R gene expression in cultured airway parasympathetic neurons. In this study, guinea pigs were treated with dsRNA (1 mg/kg ip) on 2 consecutive days. Twenty-four hours later, anesthetized guinea pigs had dysfunctional M2Rs and were hyperresponsive to electrical stimulation of the vagus nerves, in the absence of inflammation. DsRNA did not affect either cholinesterase or the function of postjunctional M3 muscarinic receptors on smooth muscle. M2Rs on the nerves supplying the heart were also dysfunctional, but M2Rs on the heart muscle itself functioned normally. Thus dsRNA causes increased bronchoconstriction and bradycardia via increased release of ACh from the vagus nerves because of loss of M2R function on parasympathetic nerves in the lungs and heart. Production of dsRNA may be a mechanism by which viruses cause dysfunction of neuronal M2Rs and airway hyperreactivity.

Animals↗
PubMed2004

Synergistic activation of innate immunity by double-stranded RNA and CpG DNA promotes enhanced antitumor activity.

Double-stranded RNA (dsRNA) and unmethylated CpG sequences in DNA are pathogen-associated molecular patterns of viruses and bacteria that activate innate immunity. To examine whether dsRNA and CpG DNA could combine to provide enhanced stimulation of innate immune cells, murine macrophages were stimulated with poly-rI:rC (pIC), a dsRNA analog, and CpG-containing oligodeoxynucleotides (CpG-ODN). Combined treatments demonstrated synergy in nitric oxide, interleukin (IL)-12, tumor necrosis factor alpha, and IL-6 production. Studies using neutralizing antibodies for type I interferons (IFNs), IFN-alpha and IFN-beta, indicated that nitric oxide synthase synergism is mediated by paracrine/autocrine effects of IFN-beta. In contrast, enhanced cytokine production occurred independent of type I IFN and was maintained in macrophages from IFN-alpha/beta receptor knockout mice. Cotransfection of human Toll-like receptors 3 and 9 (receptors for dsRNA and CpG DNA, respectively) into 293T cells supported synergistic activation of an IL-8 promoter reporter construct by pIC, indicating interaction of the signaling pathways in driving the synergy response. In vivo stimulation of mice with pIC and CpG-ODN demonstrated synergy for serum IL-6 and IL-12p40 levels that correlated with an enhanced antitumor effect against established B16-F10 experimental pulmonary metastases. Treatment of tumor-bearing mice with pIC and CpG-ODN in combination resulted in enhanced nitric oxide synthase expression in lung tissue and enhanced up-regulation of class I major histocompatibility complex on splenic dendritic cells relative to treatments with either agent alone. In conclusion, the combined detection of viral pathogen-associated molecular patterns, i.e., dsRNA and CpG DNA, may mimic definitive viral recognition, resulting in an enhanced innate immune response that could be used for tumor vaccination or immunotherapy.

Animals↗
PubMed1980

Flow cytometric analysis of double-stranded RNA content distributions.

A staining procedure is described for quantitative analysis of cellular RNA content distributions by flow cytometry (FCM). Cells were fixed in ethanol, treated with DNAse and stained with propidium iodide. FCM analysis showed that more than 90% of the fluorescence resulted from the double-stranded RNA (dsRNA) bound fluorochrome. The dsRNA content distributions were measured in HeLa S3 cells in culture 24-120 hr after plating, in L1210 ascitic leukemic cells 1-7 days after transplantation, and in regenerating bone marrow 3-7 days after injection of cyclophosphamide. In all three cell populations, maximal dsRNA content was observed during the period of most active cell proliferation, as determined by the S-phase index derived from the DNA histograms. In the dsRNA distributions in L1210 leukemia cell populations 1-2 days after transplantation, two separate peaks were evident, representing weakly fluorescent, presumably nontumor cells, and intensively fluorescent tumor cells. The amount of dsRNA-bound fluorochrome was significantly greater in L1210 cells than in normal and regenerating bone marrow cells and also greater in spontaneous thymic lymphoma cells than in normal thymic cells.

Animals↗
PubMed2001

Role of double-stranded RNA-dependent protein kinase in mediating hypersensitivity of Fanconi anemia complementation group C cells to interferon gamma, tumor necrosis factor-alpha, and double-stranded RNA.

Hematopoietic cells bearing inactivating mutations of Fanconi anemia group C (FANCC) are excessively apoptotic and demonstrate hypersensitivity not only to cross-linking agents but also to interferon gamma (IFN-gamma) and tumor necrosis factor-alpha. Seeking essential signaling pathways for this phenotype, this study quantified constitutive and induced RNA-dependent protein kinase (PKR) activation in Fanconi anemia cells of the C complementation group (FA-C). PKR was constitutively phosphorylated and exhibited an increased binding affinity for double-stranded RNA (dsRNA) in FANCC(-/-) cells. FANCC(-/-) cells were hypersensitive to both dsRNA and the combination of dsRNA and IFN-gamma in that these agents induced a higher fraction of apoptosis in FANCC(-/-) cells than in normal cells. Overexpression of wild-type PKR-sensitized FANCC(-/-) cells to apoptosis induced by IFN-gamma and dsRNA. Conversely, inhibition of PKR function by enforced expression of a dominant-negative inhibitory mutant of PKR (PKRDelta6) substantially reduced the IFN and dsRNA hypersensitivity of FANCC(-/-) cells. Two PKR target molecules, IkappaB-alpha and IRF-1, were not differentially activated in FANCC(-/-) cells, but enforced expression of a nonphosphorylatable form of eukaryotic translation initiation factor-2alpha reversed the PKR-mediated block of messenger RNA translation and partially abrogated the PKR-mediated apoptosis in FANCC(-/-) cells. Because no evidence was found of a PKR/FANCC complex in normal cells, it was concluded that an essential function of FANCC is to suppress, indirectly, the activity of PKR and that FANCC inactivation results in IFN hypersensitivity, at least in part, because this function of FANCC is abrogated.

Animals↗
PubMed2003

Disruption of vitellogenin gene function in adult honeybees by intra-abdominal injection of double-stranded RNA.

BACKGROUND: The ability to manipulate the genetic networks underlying the physiological and behavioural repertoires of the adult honeybee worker (Apis mellifera) is likely to deepen our understanding of issues such as learning and memory generation, ageing, and the regulatory anatomy of social systems in proximate as well as evolutionary terms. Here we assess two methods for probing gene function by RNA interference (RNAi) in adult honeybees. RESULTS: The vitellogenin gene was chosen as target because its expression is unlikely to have a phenotypic effect until the adult stage in bees. This allowed us to introduce dsRNA in preblastoderm eggs without affecting gene function during development. Of workers reared from eggs injected with dsRNA derived from a 504 bp stretch of the vitellogenin coding sequence, 15% had strongly reduced levels of vitellogenin mRNA. When dsRNA was introduced by intra-abdominal injection in newly emerged bees, almost all individuals (96%) showed the mutant phenotype. An RNA-fragment with an apparent size similar to the template dsRNA was still present in this group after 15 days. CONCLUSION: Injection of dsRNA in eggs at the preblastoderm stage seems to allow disruption of gene function in all developmental stages. To dissect gene function in the adult stage, the intra-abdominal injection technique seems superior to egg injection as it gives a much higher penetrance, it is much simpler, and it makes it possible to address genes that are also expressed in the embryonic, larval or pupal stages.

Abdomen↗
PubMed2003

Nuclear factor-kappaB translocation mediates double-stranded ribonucleic acid-induced NIT-1 beta-cell apoptosis and up-regulates caspase-12 and tumor necrosis factor receptor-associated ligand (TRAIL).

The mechanism of induction of apoptosis by double-stranded RNA (dsRNA) is not fully characterized. The dsRNA is normally present in extremely low quantities in cells, but following infection with RNA viruses, large quantities of the dsRNA viral replicative intermediate may be produced triggering the antiviral response as well as cell death. In this report, transfection of polyinosinic-polycytidylic acid [poly(I:C)] into NIT 1 cells has been used as a model of intracellular dsRNA-induced beta-cell apoptosis. At 18 h post transfection, 45% of the cells were apoptotic as indicated by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL) staining, and this was accompanied by an increase in nuclear factor kappaB (NF-kappaB) p50/p65 nuclear translocation and cleavage of caspases 3 and 8. The NF-kappaB inhibitor peptide, SN50, significantly reduced caspase-3 activity and the percentage of TUNEL-positive cells, substantiating a role for NF-kappaB in inducing intracellular dsRNA-mediated apoptosis. Concomitantly, RNA-dependent protein kinase activity was observed at 3 h post transfection along with phosphorylation and degradation of inhibitory kappaB-alpha. Expression of TRAIL (TNF-related apoptosis-inducing ligand), Fas, IL-15, and caspase-12 mRNAs was up-regulated in the presence of poly(I:C) but not when SN50 was also added. In contrast, there was no change detected in Fas, Fas-associated death domain, Bcl-2, Bcl-xl, Bax, p53, or XIAP(X-linked inhibitor of apoptosis protein) expression up to 12 h after poly(I:C) transfection. In addition, caspase-12 was cleaved, and phosphorylation of eukaryotic initiation factor 2alpha occurred, suggesting that an endoplasmic reticulum stress pathway was involved in addition to NF-kappaB induction of an extrinsic pathway, possibly mediated by TNF-related apoptosis-inducing ligand.

Animals↗
PubMed2003

Gene silencing in Caenorhabditis elegans by transitive RNA interference.

When a cell is exposed to double-stranded RNA (dsRNA), mRNA from the homologous gene is selectively degraded by a process called RNA interference (RNAi). Here, we provide evidence that dsRNA is amplified in Caenorhabditis elegans to ensure a robust RNAi response. Our data suggest a model in which mRNA targeted by RNAi functions as a template for 5' to 3' synthesis of new dsRNA (termed transitive RNAi). Strikingly, the effect is nonautonomous: dsRNA targeted to a gene expressed in one cell type can lead to transitive RNAi-mediated silencing of a second gene expressed in a distinct cell type. These data suggest dsRNA synthesized in vivo can mediate systemic RNAi.

Animals↗
PubMed2005

Receptor tyrosine phosphatases guide vertebrate motor axons during development.

Receptor-type protein tyrosine phosphatases (RPTPs) are required for appropriate growth of axons during nervous system development in Drosophila. In the vertebrate, type IIa RPTPs [protein tyrosine phosphatase (PTP)-delta, PTP-sigma, and LAR (leukocyte common-antigen-related)] and the type III RPTP, PTP receptor type O (PTPRO), have been implicated in the regulation of axon growth, but their roles in developmental axon guidance are unclear. PTPRO, PTP-delta, and PTP-sigma are each expressed in chick motor neurons during the period of axonogenesis. To examine potential roles of RPTPs in axon growth and guidance in vivo, we used double-stranded RNA (dsRNA) interference combined with in ovo electroporation to knock down RPTP expression levels in the embryonic chick lumbar spinal cord. Although most branches of the developing limb nerves appeared grossly normal, a dorsal nerve identified as the anterior iliotibialis was clearly affected by dsRNA knock-down of RPTPs. In experimental embryos treated with dsRNA targeting PTP-delta, PTP-sigma, or PTPRO, this nerve showed abnormal fasciculation, was reduced in size, or was missing entirely; interference with PTPRO produced the most severe phenotypes. Control embryos electroporated with vehicle, or with dsRNA targeting choline acetyltransferase or axonin-1, did not exhibit this phenotype. Surprisingly, embryos electroporated with dsRNA targeting PTP-delta together with PTPRO, or all three RPTPs combined, had less severe phenotypes than embryos treated with PTPRO alone. This result suggests that competition between type IIa and type III RPTPs can regulate motor axon outgrowth, consistent with findings in Drosophila. Our results indicate that RPTPs, and especially PTPRO, are required for axon growth and guidance in the developing vertebrate limb.

Amino Acids↗
PubMed2005

Interferon induction by viruses. XXV. Adenoviruses as inducers of interferon in developmentally aged primary chicken embryo cells.

Chicken embryonic cells (CEC) are nonpermissive hosts for the replication of human adenoviruses, yet they respond to infection by producing interferon (IFN). The nature of the IFN inducer moiety in these viruses has been elusive since its initial study by Ilona Béládi and colleagues some 40 years ago. We tested the hypothesis that viral dsRNA was the IFN inducer molecule--for two reasons: (i) dsRNA has been identified as a potent inducer of IFN, and (ii) developmentally mature CEC cells as cultured in vitro can develop a hyper-responsive state to dsRNA such that a single molecule of dsRNA per cell constitutes the threshold of detection. Furthermore, the number of particles in a virus population capable of inducing-IFN, irrespective of their replication capacity, can be quantified through the analysis of dose (multiplicity)-response (IFN yield) curves, thus allowing a determination of the number particles in virus populations that possess the capacity to induce IFN. This study demonstrates that type 5 wild type adenovirus (Ad5) and mutants dl312, dl334, and ts19 induce from 8,000 to 80,000 IFN U per 10(7) CEC. UV irradiation showed that transcription of about 20-50% of the Ad5 genome was required to produce the IFN inducer moiety. The ratio of IFN-inducing particles to plaque-forming particles (IFP : PFP) was as low as 1:6, indicating that only a small fraction of the total particles in a virus population ever function as IFP. We conclude that adenovirus dsRNA produced during symmetric transcription of some regions of the viral genome, coupled with fine-tuning of the IFN-induction pathway, account for the IFN-inducing capacity of adenoviruses in the non-permissive chicken cell.

Adenoviruses, Human↗