FIGURE 7. 3D models of influenza virus PA, AD-C209 and AD-C244+4 proteins, and selected docking models. A/C : several AD-C209 and AD-C244+4 proteins clustered on the PA model, B/D : single - AD-C209:PA and AD-C244+4:PA models, E: chemical bounds between viral PA and C244+4 proteins defined with PDBsum algorithm.
Among the docking patterns generated by using both the AD-C209 and the AD-C244+4 protein models, there are lots of matches showing an interaction between the carboxy-terminal end of the C14orf166 and PA, which is similar to the models shown in Figure 6. This result increased the interaction possibility of human C14orf166 and influenza A virus PA proteins with these regions in cells. Among these docking models, one of the PA:C244+4 interaction models, which is prominent in terms of binding properties, and the chemical bonds of interaction defined by the PDBsum algorithm are given in Figure 7C. In the evaluation made with the algorithm, fourteen hydrogen bonds and three salt bridges were detected in the interaction area between these two proteins.
Effect of C14orf166 over-expression on a viral RdRP enzyme in mammalian cells
It is known that the C14orf166 protein has a positive regulatory effect on influenza A virus replication. In this study, since it is associated with viral RdRP PA subunit, the effects of the over-expression of the C14orf166 protein on human (WSN) and avian (DkPen) type virus RdRP enzymes were investigated in HEK293 cells using minireplicon models. The results showed an average increase of 70% in the WSN-type virus polymerase enzyme (Figure 8). On the other hand, the C14orf166 over-expression stimulated the DkPen RdRP activity at a slightly lower than that of the WSN type. This result suggested that the C14orf166 protein may affect the viral RdRP activity at differ levels depending on the virus type.