pUAST consists of five tandemly arrayed optimized GAL4 binding sites followed by the hsp70 TATA box and transcriptional start , a polylinker containing unique restriction sites for EcoRI, BglII, NotI, Xho, KpnI and XbaI and the SV40 small T intron and polyadenylation site. These features are included in a P-element vector (pCaSpeR3)containing the P element ends (P3' and P5') and the white gene which acts as a marker for successful incorporation into the Drosophila genome. More information: Brand and Perimon (1993) Development 118 401-415 P element-based vector for Gal4-regulated expression of genes in Drosophila.