Figure 4. The heat shock response is virus-specific and Hsf-dependent in vivo.

Female wild-type flies (a, b, c) or Hsf ⁴ mutant flies (d) were infected with (a, d) DCV, (b) CrPV or (c) IIV-6. The expression levels of the genes encoding heat shock proteins and Heat shock factor (Hsf) were analysed by RT-qPCR at the indicated time points (a, b, c), and at 24h for DCV in panel d. Expression of the gene of interest was normalized to the housekeeping gene Ribosomal Protein 49 and presented as fold change relative to mock infection. Data are mean and s.d. of three independent experiments. Student’s t-tests were used to compare virus-infected samples to mock infections (*P < 0.05, **P < 0.01, ***P < 0.0001). Dotted lines mark the threshold of 2-fold change.