Fig. 4. CAGGcAG contributes to pre-cellular blastoderm scute function. (A) Schematic of the sc X-chromosome signal element (XSE) transgene. TAGteam sequences in the promoter region are indicated by colored symbols. (B) XSE activity of the indicated transgene based on its ability to rescue sc^null mutant females. Viability of sc^M6/sc^M6 females was measured relative to that of their sc^M6/+ sisters (n>140 per line) from the cross sc^M6w/Binsinscy X sc^M6w/Y; P{sisB w^+mC}/+ at 25°C. ^a Values from Wrischnik et al. (Wrischnik et al., 2003). Extant representative lines from the previous study were tested in parallel with the new transgenes to confirm that the comparison was valid.