tetano
Editor, Senior Moderator
J Virol. 2013 Jan 2. [Epub ahead of print]
Identification of the N-terminal domain of influenza PA responsible for the suppression of host protein synthesis.
Desmet EA, Bussey KA, Stone R, Takimoto T.
Source
Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642 USA.
Abstract
Cellular protein synthesis is suppressed during influenza virus infection, allowing for preferential production of viral proteins. To explore the impact of polymerase subunits on protein synthesis, we co-expressed eGFP or luciferase together with each polymerase component or NS1 of A/California/04/2009 (Cal) and found that PA has a significant impact on the expression of eGFP and luciferase. Comparison of the suppressive activity on co-expressed proteins between various strains revealed that avian virus or avian-origin PAs have much stronger activity than human-origin PAs, such as the one from A/WSN/33 (WSN). Protein synthesis data suggested that reduced expression of co-expressed proteins is not due to PA's reported proteolytic activity. A recombinant WSN containing Cal PA showed enhanced host protein synthesis shutoff and induction of apoptosis. Further characterization of the PA fragment indicates that the N-terminal domain (PANt), which includes the endonuclease active site, is sufficient to suppress co-transfected gene expression. By characterizing various chimeric PANt, we found that multiple regions of PA, mainly the helix α4 and the flexible loop of amino acids 51-74, affect the activity. The suppressive effect of PANt cDNA was mainly due to PA-X, which was expressed by ribosomal frameshifting. In both Cal and WSN viruses, PA-X showed a stronger effect than the corresponding PANt, suggesting that the unique C-terminal sequences of PA-X also play a role in suppressing co-transfected gene expression. Our data indicate strain variations in PA gene products, which play a major role in suppression of host protein synthesis.
PMID:
23283952
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/23283952
Identification of the N-terminal domain of influenza PA responsible for the suppression of host protein synthesis.
Desmet EA, Bussey KA, Stone R, Takimoto T.
Source
Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642 USA.
Abstract
Cellular protein synthesis is suppressed during influenza virus infection, allowing for preferential production of viral proteins. To explore the impact of polymerase subunits on protein synthesis, we co-expressed eGFP or luciferase together with each polymerase component or NS1 of A/California/04/2009 (Cal) and found that PA has a significant impact on the expression of eGFP and luciferase. Comparison of the suppressive activity on co-expressed proteins between various strains revealed that avian virus or avian-origin PAs have much stronger activity than human-origin PAs, such as the one from A/WSN/33 (WSN). Protein synthesis data suggested that reduced expression of co-expressed proteins is not due to PA's reported proteolytic activity. A recombinant WSN containing Cal PA showed enhanced host protein synthesis shutoff and induction of apoptosis. Further characterization of the PA fragment indicates that the N-terminal domain (PANt), which includes the endonuclease active site, is sufficient to suppress co-transfected gene expression. By characterizing various chimeric PANt, we found that multiple regions of PA, mainly the helix α4 and the flexible loop of amino acids 51-74, affect the activity. The suppressive effect of PANt cDNA was mainly due to PA-X, which was expressed by ribosomal frameshifting. In both Cal and WSN viruses, PA-X showed a stronger effect than the corresponding PANt, suggesting that the unique C-terminal sequences of PA-X also play a role in suppressing co-transfected gene expression. Our data indicate strain variations in PA gene products, which play a major role in suppression of host protein synthesis.
PMID:
23283952
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/23283952