A virulent strain of MeV induces and exploits autophagy.

<p>(A) CD150-stably-expressing GFP-LC3-HeLa were infected with Ed-MeV at MOI 1 or with the virulent strain of MeV G954 (G954-MeV) at MOI 1. Autophagy was monitored by the numeration of GFP+ autophagosomes 1.5 h p.i.. (B) CD150-transfected GFP-LC3-HeLa cells were infected with Ed-MeV at MOI 1 or with the virulent strain of G954-MeV at MOI 0.1. Autophagy was monitored by the numeration of GFP+ autophagosomes 24 h p.i in infected cells detected by staining for the viral nucleoprotein N (MeV-N). (C) CD150-stably-expressing HeLa cells were infected with G954-MeV (MOI 1). At the indicated time points, cellular p62 expression was determined by western blot. Representative results are shown and are accompanied by a graph representing the intensity of p62 over actin expression normalized to the control condition (non infected). Error bars, mean ± SD of two independent experiments. (D) CD150-transfected HeLa cells were infected with G954-MeV (MOI 0.1). 24 h p.i., cellular p62 expression was determined by western blot. Representative results are shown and are accompanied by a graph representing the intensity of p62 over actin expression normalized to the control condition (non infected). (E) CD150-transfected mRFP-GFP-LC3 HeLa cells were infected with G954-MeV (MOI 0.1) or treated with 250 nM Rapa or 75 µm CQ during 2 h. 24 h p.i., the autophagic vesicles were analysed as in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1003599#ppat-1003599-g004" target="_blank">figure 4D</a>. (F) CD150-transfected GFP-LC3-HeLa cells were infected with G954-MeV or UV-treated G954-MeV (MOI 0.1). 24 h post infection, the number of GFP+ vesicles per cell was assessed by confocal microscopy. (G) HeLa cells were co-transfected with a vector encoding for the H protein of KA-MeV (a CD150-dependent strain) and one encoding for the F protein of Ed-MeV. Autophagy was determined as in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1003599#ppat-1003599-g003" target="_blank">figure 3C</a>. (H) CD150-transfected HeLa cells were treated with the indicated si-RNA for 48 h and infected with G954-MeV (MOI 0.1). Two days post infection, infectious viral particles were titrated by plaque assay. For each experiment (except for (C)), error bars, mean ± SD of three independent experiments. Student's t test; ***p<0.005; **p<0.01; *p<0.05; #p>0.05.