TY - JOUR
T1 - Effects of influenza A virus NS1 protein on protein expression
T2 - The NS1 protein enhances translation and is not required for shutoff of host protein synthesis
AU - Salvatore, Mirella
AU - Basler, Christopher F.
AU - Parisien, Jean Patrick
AU - Horvath, Curt M.
AU - Bourmakina, Svetlana
AU - Zheng, Hongyong
AU - Muster, Thomas
AU - Palese, Peter
AU - García-Sastre, Adolfo
PY - 2002
Y1 - 2002
N2 - The influenza A virus NS1 protein, a virus-encoded alpha/beta interferon (IFN-α/β) antagonist, appears to be a key regulator of protein expression in infected cells. We now show that NS1 protein expression results in enhancement of reporter gene activity from transfected plasmids. This effect appears to be mediated at the translational level, and it is reminiscent of the activity of the adenoviral virus-associated I (VAI) RNA, a known inhibitor of the antiviral, IFN-induced, PKR protein. To study the effects of the NS1 protein on viral and cellular protein synthesis during influenza A virus infection, we used recombinant influenza viruses lacking the NS1 gene (delNS1) or expressing truncated NS1 proteins. Our results demonstrate that the NS1 protein is required for efficient virai protein synthesis in COS-7 cells. This activity maps to the amino-terminal domain of the NS1 protein, since cells infected with wild-type virus or with a mutant virus expressing a truncated NS1 protein - lacking approximately half of its carboxy-terminal end - showed similar kinetics of viral and cellular protein expression. Interestingly, no major differences in host cell protein synthesis shutoff or in viral protein expression were found among NS1 mutant viruses in Vero cells. Thus, another virai component(s) different from the NS1 protein is responsible for the inhibition of host protein synthesis during viral infection. In contrast to the earlier proposal suggesting that the NS1 protein regulates the levels of spliced M2 mRNA, no effects on M2 protein accumulation were seen in Vero cells infected with delNS1 virus.
AB - The influenza A virus NS1 protein, a virus-encoded alpha/beta interferon (IFN-α/β) antagonist, appears to be a key regulator of protein expression in infected cells. We now show that NS1 protein expression results in enhancement of reporter gene activity from transfected plasmids. This effect appears to be mediated at the translational level, and it is reminiscent of the activity of the adenoviral virus-associated I (VAI) RNA, a known inhibitor of the antiviral, IFN-induced, PKR protein. To study the effects of the NS1 protein on viral and cellular protein synthesis during influenza A virus infection, we used recombinant influenza viruses lacking the NS1 gene (delNS1) or expressing truncated NS1 proteins. Our results demonstrate that the NS1 protein is required for efficient virai protein synthesis in COS-7 cells. This activity maps to the amino-terminal domain of the NS1 protein, since cells infected with wild-type virus or with a mutant virus expressing a truncated NS1 protein - lacking approximately half of its carboxy-terminal end - showed similar kinetics of viral and cellular protein expression. Interestingly, no major differences in host cell protein synthesis shutoff or in viral protein expression were found among NS1 mutant viruses in Vero cells. Thus, another virai component(s) different from the NS1 protein is responsible for the inhibition of host protein synthesis during viral infection. In contrast to the earlier proposal suggesting that the NS1 protein regulates the levels of spliced M2 mRNA, no effects on M2 protein accumulation were seen in Vero cells infected with delNS1 virus.
UR - http://www.scopus.com/inward/record.url?scp=0036147256&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0036147256&partnerID=8YFLogxK
U2 - 10.1128/JVI.76.3.1206-1212.2002
DO - 10.1128/JVI.76.3.1206-1212.2002
M3 - Article
C2 - 11773396
AN - SCOPUS:0036147256
SN - 0022-538X
VL - 76
SP - 1206
EP - 1212
JO - Journal of virology
JF - Journal of virology
IS - 3
ER -