The role of phosphorylation and core protein V in adenovirus assembly

The role of phosphorylation and the minor core protein V in adenovirus type 2 assembly was examined. Comparison of the phosphoprotein composition of top components (TC), young virions and mature virions of wild-type and assembly mutants showed specific changes related to virus assembly and maturation. TC were identified as precursors of young virions which contain two molecular weight forms of core protein V, one of which is phosphorylated. Conversion of TC into young virions by DNA encapsidation resulted in the loss of the unphosphorylated form of protein V, and subsequent maturation to old virions resulted in the dephosphorylation of the core protein. This last step is blocked by the tsl mutation which inactivates the viral endoproteinase.