Comparison of RNP activities containing hybrid polymerases between H5N1 strains and human strains in vivo.

<p>Polymerase subunits of human strains of A/WSN/1933 (H1N1) (<b>W</b>), A/Kurume/K0910/2009 (H1N1) (S) and A/NT/60/1968 (H3N2) (N) were replaced with the corresponding subunits of A/HongKong/156/1997 (H5N1) (H) (left 3 panels) or A/Vietnam/1194/2004 (H5N1) (V) (right 3 panels). The RNP was reconstituted in 293T cells by transfection of plasmids expressing various combinations of polymerase subunits, and WSN derived NP and vNA. Total RNA was extracted 30 h posttransfection. Transcript products of viral mRNA, cRNA and vRNA were measured by primer extension and its positions are indicated on the right. The expected size of mRNA, cRNA, vRNA and 5S rRNA as an internal control are 169–177 nt, 160 nt, 129 nt and 100 nt, respectively.