cDNA derived from cells that were mock-infected or inoculated with 1000 particles/cell of entry-defective DgB, DgD and DgH virions was used for real-time PCR analysis. Primers were designed, using the Primer3 software [23] , to anneal at 60uC, with a minimum product melting temperature of 80uC (Table S2) . Reactions were set-up with cDNA corresponding to 100 ng total RNA, primers (70 nM), and 10 ml SYBR Green PCR master mix (Abgene) made to a total volume of 20 ml with nuclease-free dH 2 O. A Corbett Rotorgene 3000 was used to determine the levels of SYBR green fluorescence over 40 cycles. Samples were denatured for 10 minutes at 95uC, annealed at 60uC for 30 seconds, with extension of the primer product at 72uC for 40 seconds then a final 80uC step for 20 seconds that removes background fluorescence from primer-dimers. A melt curve analysis was produced at the end of the cycling to ensure the specificity of PCR product amplification and associated SYBR green fluorescence. Relative gene expression levels between mockinoculated and inoculated cells were calculated using the Pfaffl method with potential variations in cDNA quantity between samples normalised to the transcript for ribosomal protein L13a (RPL13a) [24] . Serial dilutions of PCR product across 8 logs were used to determine the efficiency of PCR amplification for each primer set under the above conditions so that the relative quantitation could be adjusted as defined by the Pfaffl method.