ACIDIC DOMAIN OF THE PHOSPHOPROTEIN (P) OF VESICULAR STOMATITIS-VIRUSDIFFERENTIALLY INTERACTS WITH HOMOLOGOUS AND HETEROLOGOUS NUCLEOCAPSID PROTEIN (N)

The homologous and heterologous interactions between the nucleocapsid protein N and the phospho-protein P of New Jersey and Indiana serotype s of vesicular stomatitis virus were studied. SP6 derived N and P mRNA s were cotranslated in rabbit reticulocyte lysate and the complexes fo rmed thereof were analyzed by 7.5% nondenaturing polyacrylamide gel el ectrophoresis. P protein of VSV(NJ) has two binding sites for homologo us N protein: One located within the C-terminal 11 amino acids (within domain III) is responsible for the formation of five specific complex es while the other site, which spans the acidic domain I, is necessary for the formation of the sixth complex only. In contrast, P(IND) does not form the sixth complex when interacted with homologous N protein. Interestingly, P(NJ) forms only complexes 1 to 5 when it interacts wi th N(IND). The above results suggest that the complex 6 formation or d omain I interacting site is NJ-serotype specific. Two chimeric P prote ins were made using heterologous domains I and II/III of the P protein s of both serotypes. The soluble interaction of the chimeric proteins with the N protein supported the observed serotype specific interactio ns. The chimeric P proteins bound with equal efficiency with N-RNA tem plate of both serotypes. These results strongly suggest that the acidi c domain I of the P protein differentially interacts with homologous a nd heterologous N proteins. The biological significance of these findi ngs is discussed.