scholarly journals Characterisation of the nucleic acid binding features of the PRRSV 7ap and its ability to induce antinuclear antibodies

2017 ◽  
Vol 65 (1) ◽  
pp. 124-134 ◽  
Author(s):  
Ferenc Olasz ◽  
Béla Dénes ◽  
Ádám Bálint ◽  
Tibor Magyar ◽  
Sándor Belák ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Antinuclear Antibodies ◽  
Respiratory Syndrome Virus ◽  
Type I ◽  
Nucleic Acid Binding ◽  
Reading Frame ◽  
Nucleocapsid Gene ◽  
Dna Binding Properties ◽  
Alternative Open Reading Frame ◽  
Net Positive Charge

A short alternative open reading frame named ORF7a has recently been discovered within the nucleocapsid gene of the porcine reproductive and respiratory syndrome virus (PRRSV) genome. Proteins (7ap) translated from the ORF7a of two divergent strains — a type I and a type II — are able to completely reduce the motility of nucleic acids at relatively high molar charge ratios in gel retardation assays indicating strong dsDNA- and ssRNA-binding capability. Conserved RNA- and DNA-binding properties suggest that nucleic acid binding is a functional property of the divergent 7aps, and not an arbitrary consequence of their net positive charge. Sera from Hu7ap-immunised pigs and mice did not react with Hu7ap or Hu7ap-GFP; however, antinuclear antibodies were detected in the sera of the immunised animals, suggesting an ability of Hu7ap to interact with or mimic autoantigenic macromolecules.

scholarly journals Cellular nucleic acid–binding protein is essential for type I interferon–mediated immunity to RNA virus infection

2021 ◽  
Vol 118 (26) ◽  
pp. e2100383118
Author(s):  
Yongzhi Chen ◽  
Xuqiu Lei ◽  
Zhaozhao Jiang ◽  
Katherine A. Fitzgerald
Keyword(s):  
Gene Expression ◽  
Nucleic Acid ◽  
Virus Infection ◽  
Rna Virus ◽  
Innate Immune ◽  
Type I ◽  
Type I Ifn ◽  
Nucleic Acid Binding ◽  
Nucleic Acid Binding Protein ◽  
Acid Binding Protein

Type I interferons (IFNs) are innate immune cytokines required to establish cellular host defense. Precise control of IFN gene expression is crucial to maintaining immune homeostasis. Here, we demonstrated that cellular nucleic acid–binding protein (CNBP) was required for the production of type I IFNs in response to RNA virus infection. CNBP deficiency markedly impaired IFN production in macrophages and dendritic cells that were infected with a panel of RNA viruses or stimulated with synthetic double-stranded RNA. Furthermore, CNBP-deficient mice were more susceptible to influenza virus infection than were wild-type mice. Mechanistically, CNBP was phosphorylated and translocated to the nucleus, where it directly binds to the promoter of IFNb in response to RNA virus infection. Furthermore, CNBP controlled the recruitment of IFN regulatory factor (IRF) 3 and IRF7 to IFN promoters for the maximal induction of IFNb gene expression. These studies reveal a previously unrecognized role for CNBP as a transcriptional regulator of type I IFN genes engaged downstream of RNA virus–mediated innate immune signaling, which provides an additional layer of control for IRF3- and IRF7-dependent type I IFN gene expression and the antiviral innate immune response.

scholarly journals Immunological and biochemical characterisation of 7ap, a short protein translated from an alternative frame of ORF7 of PRRSV

2016 ◽  
Vol 64 (2) ◽  
pp. 273-287 ◽  
Author(s):  
Ferenc Olasz ◽  
Béla Dénes ◽  
Ádám Bálint ◽  
Tibor Magyar ◽  
Sándor Belák ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Respiratory Syndrome Virus ◽  
Reading Frame ◽  
Nucleocapsid Gene ◽  
Cellular Processes ◽  
Protein Gel ◽  
Cellular Localisation ◽  
Biochemical Characterisation ◽  
Green Fluorescent ◽  
Substantial Heterogeneity

Sequence analysis revealed a short alternative open reading frame (ORF) named ORF7a within the nucleocapsid gene of genetically divergent porcine reproductive and respiratory syndrome virus (PRRSV) genomes. Alignment of the corresponding protein sequences (named 7ap) revealed substantial heterogeneity among 7aps of different genotypes, though all of them are predicted to be positively charged. Green fluorescent protein and FLAG fusion constructs of ORF7a of the HU-14432/2011 PRRSV demonstrated that 7ap is expressed. 7ap of HU- 14432/2011 (Hu7ap) was synthesised chemically, and ELISA experiments revealed that Hu7ap binds strongly to mammalian IgGs. Protein-protein gel retardation assays and complement fixation inhibition suggest that 7aps bind to the CH2 domain of the IgG(Fc) fragment. Cellular localisation and immunological characteristics of PRRSV 7ap may indicate multiple functions including nuclear and cytoplasmic over-tuning of normal cellular processes and immunosuppression.

Sites of Nucleic Acid Binding in Type I−IV Intermediate Filament Subunit Proteins†

Biochemistry ◽  
2001 ◽  
Vol 40 (34) ◽  
pp. 10342-10349 ◽  
Author(s):  
Qiang Wang ◽  
Genrich V. Tolstonog ◽  
Robert Shoeman ◽  
Peter Traub
Keyword(s):  
Nucleic Acid ◽  
Intermediate Filament ◽  
Type I ◽  
Nucleic Acid Binding

scholarly journals Dependence of RIG-I Nucleic Acid-Binding and ATP Hydrolysis on Activation of Type I Interferon Response

2016 ◽  
Vol 16 (4) ◽  
pp. 249 ◽  
Author(s):  
Yu Mi Baek ◽  
Soojin Yoon ◽  
Yeo Eun Hwang ◽  
Dong-Eun Kim
Keyword(s):  
Nucleic Acid ◽  
Atp Hydrolysis ◽  
Type I Interferon ◽  
Interferon Response ◽  
Type I ◽  
Nucleic Acid Binding

scholarly journals Cyclic Guanosine Monophosphate–Adenosine Monophosphate Synthase (cGAS), a Multifaceted Platform of Intracellular DNA Sensing

2021 ◽  
Vol 12 ◽  
Author(s):  
Eloi R. Verrier ◽  
Christelle Langevin
Keyword(s):  
Nucleic Acid ◽  
Current Knowledge ◽  
Adenosine Monophosphate ◽  
Cyclic Guanosine Monophosphate ◽  
Innate Immune ◽  
Guanosine Monophosphate ◽  
Type I ◽  
Nucleic Acid Binding ◽  
Sting Pathway ◽  
Molecular Patterns

Innate immune pathways are the first line of cellular defense against pathogen infections ranging from bacteria to Metazoa. These pathways are activated following the recognition of pathogen associated molecular patterns (PAMPs) by membrane and cytosolic pattern recognition receptors. In addition, some of these cellular sensors can also recognize endogenous danger-associated molecular patterns (DAMPs) arising from damaged or dying cells and triggering innate immune responses. Among the cytosolic nucleic acid sensors, the cyclic guanosine monophosphate–adenosine monophosphate (cGAMP) synthase (cGAS) plays an essential role in the activation of the type I interferon (IFNs) response and the production of pro-inflammatory cytokines. Indeed, upon nucleic acid binding, cGAS synthesizes cGAMP, a second messenger mediating the activation of the STING signaling pathway. The functional conservation of the cGAS-STING pathway during evolution highlights its importance in host cellular surveillance against pathogen infections. Apart from their functions in immunity, cGAS and STING also play major roles in nuclear functions and tumor development. Therefore, cGAS-STING is now considered as an attractive target to identify novel biomarkers and design therapeutics for auto-inflammatory and autoimmune disorders as well as infectious diseases and cancer. Here, we review the current knowledge about the structure of cGAS and the evolution from bacteria to Metazoa and present its main functions in defense against pathogens and cancer, in connection with STING. The advantages and limitations of in vivo models relevant for studying the cGAS-STING pathway will be discussed for the notion of species specificity and in the context of their integration into therapeutic screening assays targeting cGAG and/or STING.

scholarly journals Cross-species analysis of viral nucleic acid interacting proteins identifies TAOKs as innate immune regulators

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Friederike L. Pennemann ◽  
Assel Mussabekova ◽  
Christian Urban ◽  
Alexey Stukalov ◽  
Line Lykke Andersen ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Nucleic Acids ◽  
Functional Characterization ◽  
Genetic Material ◽  
Type I ◽  
Nucleic Acid Binding ◽  
Virus Growth ◽  
Interferon Stimulated Genes ◽  
Nucleic Acid Binding Proteins ◽  
Species Specific

AbstractThe cell intrinsic antiviral response of multicellular organisms developed over millions of years and critically relies on the ability to sense and eliminate viral nucleic acids. Here we use an affinity proteomics approach in evolutionary distant species (human, mouse and fly) to identify proteins that are conserved in their ability to associate with diverse viral nucleic acids. This approach shows a core of orthologous proteins targeting viral genetic material and species-specific interactions. Functional characterization of the influence of 181 candidates on replication of 6 distinct viruses in human cells and flies identifies 128 nucleic acid binding proteins with an impact on virus growth. We identify the family of TAO kinases (TAOK1, −2 and −3) as dsRNA-interacting antiviral proteins and show their requirement for type-I interferon induction. Depletion of TAO kinases in mammals or flies leads to an impaired response to virus infection characterized by a reduced induction of interferon stimulated genes in mammals and impaired expression of srg1 and diedel in flies. Overall, our study shows a larger set of proteins able to mediate the interaction between viral genetic material and host factors than anticipated so far, attesting to the ancestral roots of innate immunity and to the lineage-specific pressures exerted by viruses.

scholarly journals Autosomal dominant retinitis pigmentosa mutations in inosine 5′-monophosphate dehydrogenase type I disrupt nucleic acid binding

2005 ◽  
Vol 390 (1) ◽  
pp. 41-47 ◽  
Author(s):  
Sarah E. Mortimer ◽  
Lizbeth Hedstrom
Keyword(s):  
Enzyme Activity ◽  
Nucleic Acid ◽  
Retinitis Pigmentosa ◽  
Autosomal Dominant ◽  
Functional Assay ◽  
Type I ◽  
Guanine Nucleotide ◽  
Nucleic Acid Binding ◽  
Autosomal Dominant Retinitis Pigmentosa ◽  
Monophosphate Dehydrogenase

Two mutations of IMPDH1 (inosine 5′-monophosphate dehydrogenase type I), R224P and D226N, have recently been found to cause adRP (autosomal dominant retinitis pigmentosa). IMPDH1 catalyses the rate-limiting step in guanine nucleotide biosynthesis and also binds single-stranded nucleic acids. In the present paper, we report the biochemical characterization of the adRP-linked mutations, R224P and D226N, and a potentially pathogenic mutation, V268I. The adRP-linked mutations have no effect on enzyme activity, protein stability or protein aggregation. These results suggest strongly that the mutations do not affect enzyme activity in vivo and thus do not perturb the guanine nucleotide pool. The R224P mutation changes the distribution of enzyme between the nucleus and cytoplasm. This effect was not observed with the D226N mutation, so the relevance of this observation to disease is unclear. In contrast, both mutations decrease the affinity of nucleic acid binding and both fail to co-immunoprecipitate RNA. These observations suggest that nucleic acid binding provides a functional assay for adRP pathogenicity. The putative adRP-linked mutation V268I also disrupts nucleic acid binding, which suggests that this mutation is indeed pathogenic.

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