The N-terminal region of the PA subunit of the RNA polymerase of influenza A/HongKong/156/97 (H5N1) influences promoter binding.
BACKGROUND
The RNA polymerase of influenza virus is a heterotrimeric complex of PB1, PB2 and PA subunits which cooperate in the transcription and replication of the viral genome. Previous research has shown that the N-terminal region of the PA subunit of influenza A/WSN/33 (H1N1) virus is involved in promoter binding.


RESULTS
Here we extend our studies of the influenza RNA polymerase to that of influenza strains A/HongKong/156/97 (H5N1) and A/Vietnam/1194/04 (H5N1). Both H5N1 strains, originally isolated from patients in 1997 and 2004, showed significantly higher polymerase activity compared with two classical human strains, A/WSN/33 (H1N1) and A/NT/60/68 (H3N2) in vitro. This increased polymerase activity correlated with enhanced promoter binding. The N-terminal region of the PA subunit was the major determinant of this enhanced promoter activity.


CONCLUSIONS
Overall we suggest that the N-terminal region of the PA subunit of two recent H5N1 strains can influence promoter binding and we speculate this may be a factor in their virulence.
Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
Takahito
T
Kashiwagi
Bo Wah
BW
Leung
Tao
T
Deng
Hualan
H
Chen
George G
GG
Brownlee
D000818:Animals; D002642:Chick Embryo / Q000166:cytology / Q000821:virology; D002645:Chickens; D003432:Cross-Linking Reagents; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000201:enzymology* / Q000235:genetics; D007668:Kidney / Q000166:cytology / Q000821:virology; D011401:Promoter Regions, Genetic / Q000502:physiology*; D012367:RNA, Viral / Q000378:metabolism*; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D014466:Ultraviolet Rays; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication
D003432:Cross-Linking Reagents; C061290:PA protein, influenza viruses; D012367:RNA, Viral; D012261:Ribonucleoproteins; D014764:Viral Proteins; D012324:RNA-Dependent RNA Polymerase; D012321:DNA-Directed RNA Polymerases