FIGURE 2 The function of UASGAL sequences was confirmed in reporter gene assays in which promoter activity was determined by the activity of β-galactosidase (produced by the bacterial lacZ gene). As shown in these five assays (1 is the wild-type), deletion or mutation of UASGAL elements, but not other areas close to the promoter, resulted in decreased promoter activity (β-galactosidase level).