Figure 2.

Eukaryotic HATs acetylated NP in vitro. A, the recombinant protein of NP derived from E. coli was acetylated by PCAF and GCN5, but not by the nuclear extract or by P300/CBP. Histone H1 was used as the positive control for acetylation. B, acetylation levels on the recombinant protein of the NP depended on incubation duration with the enzymes. The extra bands, from contamination of E. coli proteins, are indicated by blank arrowheads. C, RNP purified from virions of A/Puerto Rico/8/34 (PR8, H1N1) was incubated with PCAF and GCN5. NP constructing RNP was acetylated by PCAF and GCN5. Autoacetylation on the partial recombinant proteins of PCAF and GCN5 was also detected around the mass of 20 kDa. Arrowheads show the bands of NP. Upper and lower pictures of both panels show the results of Coomassie Brilliant Blue (CBB) staining and autoradiography, respectively.