[1] Univ Cologne, Inst Virol, Fac Med, Furst Puckler Str 56, D-50935 Cologne, Germany
[2] Univ Cologne, Univ Hosp Cologne, Furst Puckler Str 56, D-50935 Cologne, Germany
[3] Czech Acad Sci, Dept Biol Cell Nucleus, Inst Mol Genet, Prague, Czech Republic
[4] Charles Univ Prague, Fac Sci, Vinicna Microscopy Core Facil, Prague, Czech Republic