Figure 7

Morphological changes in WT MCMV and ∆M25 mutant infected cells and in cells transfected with M25 expression plasmids. (a) NIH 3T3 cells were infected with WT MCMV or the ∆M25 mutant or were mock infected. Cells were fixed at the indicated time points, labelled with TRITC-phalloidin and analyzed by confocal microscopy. Positive staining of actin appears black or dark grey. Infected cells are distinguished by virus-driven GFP expression. Size bars, 10 µm. (b) Diameters of the infected cells (treated as indicated in (a)) were determined. (c,d) NIH3T3 cells were either mock transfected or transfected with plasmids pM25l, pM25s and control plasmids encoding the viral proteins M44 or M82 or E.coli ß-galactosidase (lacZ). After 24 h cells were fixed, labeled with Alexa Fluor 488 phalloidin, and antibodies directed against GAPDH and the myc epitope, and examined by confocal microscopy. Transfected cells were identified by the myc signal. Size bars, 10 µm. (c) Cell diameters as determined 24 h after transfection. Bars represent medians. Statistical significance was tested using the Kruskal-Wallis test followed by Dunn’s post hoc test. ***P < 0.001; **P < 0.01. (d) Representative images of cell cultures transfected with M25l, M25s or M44 plasmids. Phalloidin (actin) staining is depicted in the top row and merged signals of phalloidin, GAPDH and myc labeling are shown below. Transfected cells (myc + signal in green) are indicated by arrows.