Fig. 4. Expression levels of X-linked genes are reduced in males deficient in SCF function. To generate control individuals (carrying only GAL4) or RNAi-induced individuals (carrying both GAL4 and UAS-IRscf), the Act5C-GAL4 driver was crossed to yw or yw; [UAS-IRscf] (line 2-1) at 25°C. The effect of SCF reduction on the expression levels of the X-linked genes (Zw, Sgs4, Pgd, BR-C, Gs2 and mRpL16) and the autosomal genes (Dspt4, Rp49, blue and trio) was examined by quantitative RT-PCR. The level of transcripts from each gene was normalized to an internal standard (ß1-tubulin) and then individuals deficient in SCF function via RNAi were compared with control individuals. Relative level of mRNA means the ratio of values relative to the value of the control female; error bars represent s.d. of at least three different samples.