Figure 10.

GRA24 triggers up-regulated expression of the host transcription factors Egr-1 and c-FOS. (A) Heatmap representation of host transcription factors up-regulated in a GRA24-dependent fashion in BMDM infected by the aforementioned strains. Egr-1 and c-FOS are indicated in red. (B) IFA of GRA24-dependent induction of Egr-1 (red) in uninfected (u.i.) or infected (24 h) HFF by the indicated strains. Images are representative of at least four experiments. Bar, 20 µm. (C) Cellular fractionation of J774 cells left uninfected (u.i.) or infected (24 h) by the indicated strains. Cytoplasmic (C) and nuclear (N) fractions were analyzed by Western blotting using indicated antibodies. TBP (host-specific) and toxofilin (parasite-specific) are shown as loading controls. Data are representative of three experiments. (D) Western blot analysis of nuclear fractions of 293-TRex cell line expressing GRA24-HF using indicated antibodies. Cells were either left untreated (− Tet) or treated (+ Tet) with 1 µg/ml tetracycline for 20 h. AcH4 was used to assess host nuclear protein enrichment. Data are representative of three experiments. (E) IFA showing the serine 32 phosphorylation status of c-FOS (in red) in serum-starved confluent HFF left uninfected (u.i.) or after 24 h of infection by RHku80, RHku80 Δgra24, and RHku80 Δgra24, GRA24⁺ parasites. Images are representative of two experiments. Bar, 20 µm.