Knock-out of the nuclear localization in pp65 protein of Cytomegalovirus: biologic and immunologic effects

The CMVpp65 protein contains 2 bipartite nuclear localization signals (NLS) at 415-438aa and 537-561aa near the carboxy terminus of CMVpp65 and a phosphate binding site related to kinase activity at lysine-436. A mutation of pp65 having K436N (CMVpp65mII) and further deletion of aa537-561 resulted in a novel protein (pp65mIINLSKO) that is kinase-less and has markedly reduced nuclear localization. The purpose of this report was to study the biologic characterization of this protein and its immunogenicity compared to native pp65.Using RNA microarray analysis, expression of the CMVpp65mIINLSKO had less effect on cell cycle pathways than did the native CMVpp65 and a greater effect on cell surface signalling pathways involving immune activity. It is concluded that the removal of the primary NLS motif from pp65 does not impair its immunogenicity and may actually be advantageous in the design of a vaccine.

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Zaia JA, Li X, Franck AE, Wu X, Thao L, Gallez-Hawkins G