Activation of the Mitochondrial Apoptotic Signaling Platform during Rubella Virus Infection

Claus, Claudia; Manssen, Lena; Hübner, Denise; Roßmark, Sarah; Bothe, Viktoria; Petzold, Alice; Große, Claudia; Reins, Mareen; Mankertz, Annette; Frey, Teryl K.; Liebert, Uwe G.

Viruses 2015, 7, page-page Finally, the intracellular distribution of cyclophilin A (CypA), which is involved in apoptotic processes and acts as a host factor for several viruses [24] , was investigated. Immunofluorescence analysis was performed after permeabilization with two different detergents. Triton X-100 partially dissolves the nuclear membrane, while Tween 20 enables staining of mainly cytoplasmic proteins. Figure 7A highlights that after permeabilization with Tween 20, hardly any differences between mock-and RV-infected Vero cells and Vero cells after overnight incubation with 0.003% hydrogen peroxide are noticeable. This is in contrast to permeabilization with Triton X-100, which shows a clear shift of CypA from a cytoplasmic to a nuclear localization ( Figure 7B(12) ). However, as compared to the mock-infected control, only a slight shift of CypA to the nucleus can be speculated after infection with RV ( Figure 7B (4) and 7B (8)). In conclusion, during RV infection, nuclear translocation of Cyp40, but not of CypA, is detectable. Figure 7 . Impact of RV infection on intracellular distribution of cyclophilin A. Immunofluorescence analysis was performed with anti-CypA antibody (shown in red) and anti-E1 antibody (shown in green) for RV-and mock-infected Vero cells (3 dpi). Nuclear DNA is shown in blue. Pink colour indicates overlap areas. As a control, overnight incubation with 0.003% hydrogen peroxide (H2O2) was included. After fixation with 2% (w/v) paraformealdehyde, cells were permeabilized with 0.1% TritonX-100 (A) or with 0.3% Tween 20 (B). Arrows point to representative cells with a clear shift of CypA to the nucleus. Scale bar, 10 μm.