Since hemagglutinin (HA) and non-structural 1 (NS1) proteins are relevant in respect of adaptive and innate immune responses, the present study was aimed at establishing the intra-host genetic heterogeneity of HA and NS1 genes, applying ultra-deep pyrosequencing (UDPS) to nasopharyngeal swabs (NPS) from patients with confirmed influenza A(H1N1)pdm09 infection.
Here, we demonstrate that UAP56 also co-localizes with the influenza A viral NS1 protein, which counteracts host cell innate immune responses stimulated by virus infection.
These results revealed a novel mechanism by which the NS1 protein of the 2009 pandemic H1N1 suppresses NLRP3 inflammasome activation.<b>IMPORTANCE</b> Influenza A virus (IAV) infection activates the NLRP3 inflammasome, resulting in the production of IL-1β, which contributes to the host innate immune response.
Allele B NS1 proteins from corresponding subtypes of influenza A viruses are weak in this inhibition, despite significant levels of expression of each NS1 protein in human A549 cells.
These changes occur at the ends of highly transcribed genes, where global inhibition of transcription termination by IAVNS1 protein causes readthrough transcription for hundreds of kilobases.
The study has demonstrated, for the first time, the expression of nonstructural 1 (NS1) protein of influenza A virus H5N1 on the cell wall of Lactobacillus casei using the pSGANC332 expression plasmid.
Rational characterization of virulence and host-adaptive markers in the multifunctional influenza A virus NS1 protein is hindered by a lack of comprehensive knowledge about NS1-host protein protein interfaces.
In a BSL3+ laboratory, viruses were generated that possessed either the 1918 NS1 gene alone or the entire 1918 NS segment in a background of influenza A/WSN/33 (H1N1), a mouse-adapted virus derived from a human influenza strain first isolated in 1933.
Indeed, a number of mammalian VSRs have been described, of which the most prominent is the influenza A virus (IAV) NS1 protein, which has not only been reported to inhibit RNAi in plants and insects but also to prevent the production of viral siRNAs in IAV-infected human cells.
The present study used a clone of the NS1 gene from avian influenza A/Jiangsu/1/2007 and observed the localization of the NS1 protein and cytochrome <i>c</i> release from mitochondria and the change of mitochondrial membrane potential (MMP) in lung cancer cells.
The fact that influenza A and influenza B virus NS1 proteins bind to NS1-I suggests that this cellular protein plays a role in the influenza virus life cycle.
Strains of the 2009 H1N1 pandemic influenza A virus could be divided into two categories based on the V123I mutation in the NS1 gene: G1 (characterized as 123 Val) and G2 (characterized as 123 Ile).
Our results indicate that the NS1 protein of bat influenza A-like viruses is less efficient than the NS1 protein of its conventional influenza A virus NS1 counterpart in antagonizing the IFN response and that this deficiency can be overcome by the influenza virus PB2 protein.<b>IMPORTANCE</b> Significant gaps in our understanding of the basic features of the recently discovered bat influenza A-like viruses HL17NL10 and HL18NL11 remain.
Most significantly, a virus containing the 1918 pandemic NS1 gene was more efficient at blocking the expression of IFN-regulated genes than its parental influenza A/WSN/33 virus.
Here we show that the interaction between NS1 protein of influenza A/Shantou/602/06 (H3N2) and nucleolin, a ubiquitous protein of nucleolus repressed RNA Pol I-dependent transcription via establishing hyper-methylation in the UCE of rRNA gene promoter.
Thus, we identify the NS1 protein as a potential trigger of the epigenetic deregulation of JAK-STAT signaling suppressors and illustrate a novel mechanism underlying the regulation of host immunity during IAV infection.