FIG 4.

c-Myc is transcriptionally regulated in Toxoplasma-infected cells. (A) RAW 264.7 macrophages were infected with Toxoplasma RH parasites at an MOI of 3 [Toxo (24hpi)], or treated with syringe-lysed uninfected HFF cultures (Mock), in duplicate. At 24 hpi, RNA was prepared from each culture and analyzed by hybridization to microarrays. The graph depicts the fold increase in c-Myc mRNA abundance relative to mock-treated cells. (B) Cells expressing a reporter containing the fusion of the c-Myc promoter with a luciferase coding region (Luc) were infected with Toxoplasma (Toxo) at an MOI of 0.1 or 1 or Neospora (Neo) at an MOI of 1 or were treated with 20% FBS (FBS) as a positive control for c-Myc induction. Infected cells were lysed 20 hpi, and lysates were analyzed for luminescence upon addition of luciferin substrate. All values are relative to mock-infected samples. Statistical analysis was done by unpaired t test; a double asterisk (**) indicates P < 0.005.