PHOSPHORYLATION OF TICK-BORNE ENCEPHALITIS-VIRUS NS5 PROTEIN

The largest tick-borne encephalitis virus (TBEV) non-structural protei n NS5 (100 kDa) is believed to be involved in RNA replication. The pro tein is phosphorylated in infected cell extracts in the presence of [g amma-P-32]ATP, as shown by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis using monoclonal antibodies raised against TBEV NS5 protein. Radioactive labeling of NS 5 in cellular extracts at an early stage post-infection is higher than at 24 h post-infection. Incubation of immunoprecipitates of NS5 prote in with [gamma-P-32]ATP in the presence of Mg2+ resulted in the phosph orylation of TBEV NS5 protein and of immunoglobulins. Phosphoamino aci d analysis demonstrated that NS5 contains phosphoserine, but not phosp hothreonine, or phosphotyrosine. (C) 1997 Elsevier Science B.V.