Additional Evidence That the Polymerase Subunits Contribute to the Viral Replication and the Virulence of H5N1 Avian Influenza Virus Isolates in Mice.
Genetically similar H5N1 viruses circulating in the avian reservoir exhibit different levels of pathogenicity in mice. In this study, we characterized two highly pathogenic H5N1 avian isolates--A/Hunan/316/2005 (HN05), which is highly pathogenic in mice, and A/Hubei/489/2004 (HB04), which is nonpathogenic. In mammalian cells, HN05 replicates more efficiently than HB04, although both viruses have similar growth kinetics in avian cells. We used reverse genetics to generate recombinant H5N1 strains containing genes from HN05 and HB04 and examined their virulence. HN05 genes encoding the polymerase complex determine pathogenicity and viral replication ability both in vitro and in vivo. The PB2 subunit plays an important role in enhancing viral replication, and the PB1 and PA subunits contribute mainly to pathogenicity in mice. These results can be used to elucidate host-range expansion and the molecular basis of the high virulence of H5N1 viruses in mammalian species.
State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
Xiao
X
Qu
State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
Longfei
L
Ding
State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
Zhenqiao
Z
Qin
State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
Jianguo
J
Wu
State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
Zishu
Z
Pan
D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D002645:Chickens / Q000821:virology; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D005260:Female; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000254:growth & development / Q000302:isolation & purification / Q000472:pathogenicity* / Q000502:physiology*; D008810:Mice, Inbred C57BL; D009976:Orthomyxoviridae Infections / Q000201:enzymology* / Q000821:virology*; D021122:Protein Subunits / Q000378:metabolism*; D016865:Reassortant Viruses / Q000472:pathogenicity; D011995:Recombination, Genetic / Q000235:genetics; D012261:Ribonucleoproteins / Q000378:metabolism; D014774:Virulence; D014779:Virus Replication
D000596:Amino Acids; D021122:Protein Subunits; D012261:Ribonucleoproteins; D012321:DNA-Directed RNA Polymerases