To study the properties of MPyV minor capsid proteins, and extent and character of cytotoxicity induced by them, several plasmids for individual production of VP2, VP3 and their EGFP fusion variants were constructed. Minor protein localisation in mouse cells, cell death and the presence of apoptosis markers during their transient expression as well as during the infection cycle of wt MPyV and mutated MPyV lacking both minor proteins were analysed.