Redistribution of cellular organelles in T40-AV-infected astrocytes. Double-label immunofluorescence staining with MitoTracker (Mit) for mitochondria and β-tubulin (Tub) before (A) or after (B) 8 hr of T40-AV infection, for Mit and tau (C), as well as for Mit with GFP (D) 8 hr after infection. Double-label immunofluorescence staining of calnexin (Cal, E-H), a marker for ER, and MG160 (I-N), a marker for the GA, in astrocytes before (A, E, I, K) or after (B, C, F, G, J, L-N) infection with T40-AV or with GFP-AV (D, H). Mitochondria (green) and ER (green) spread over the whole cytoplasm and reached the distal ends of MTs in astrocytes before infection (A, E) and with GFP-AV infection (D, H), whereas the mitochondria and ER accumulated in the vicinity of the nucleus 8 hr after T40-AV infection (B, C, F, G), even in the cells showing preserved MT networks (B, F) and expressing small amounts of tau (C, G). However, the collapse of the ER did not lead to changes in the expression level of calnexin (O). D has a high red pseudocolor fluorescent signal attributable to the expression of GFP. The GA was clearly stained with the anti-MG160 antibody in non-infected astrocytes (I), in which the staining appeared in the anastomotic reticulum and extended to a considerable distance (K). GA staining distinctly decreased 8 hr after T40-AV infection (J), and fragmentation of the GA occurred, as shown in higher magnification (M). This fragmentation of the GA was observed as early as 4 hr after T40-AV infection (L). Double immunostaining for MG160 (red) and tau (17026; green) indicated the relationship between the loss of GA and the expression of tau (N): cells with higher expression levels of tau lost their GA (N, arrowheads), and cells with lower expression levels of tau had some GA remaining (N, arrow). Western blot analysis showed decreased expression of MG160 (O), which is consistent with the immunofluorescence staining. Mit, MitoTracker; Cal, calnexin; Tub, tubulin. Scale bars, 10 μm.