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.

After assessment of the mPTP opening, intracellular distribution of AIF was documented after its overexpression. At 2 hpi, mock-and RV-infected Vero cells were transfected with a plasmid encoding AIF-TagRFP (red fluorescent protein). At 48 h post-infection and post-transfection, distribution of AIF-TagRFP was analyzed. Upon RV infection, AIF-TagRFP can be found in mitochondria, as expected, and as it was oberserved in mock-infected cells ( Figure 3A ). However, in contrast to the mock infection, AIF-TagRFP can also be found in the nucleus and especially in areas of condensed chromatin (Figure 3Aa-d) . In some cases, nuclear counterstaining with Hoechst bisbenzamide was hardly traceable (Figure 3Ad ). However, Western blot analysis with anti-AIF antibody revealed no detectable change in AIF concentration in the mitochondria-enriched fraction derived at 3 dpi from RV-infected Vero cells as compared to the one obtained from mock-infected cells ( Figure 3B ). This indicates that only a minor portion of mitochondrial AIF translocates towards the nucleus during RV infection.