Targeted gain-of-function screening inDrosophilausingGAL4-UASand random transposon insertions

Abstract

SummaryAlterations in the activity level or temporal expression of key signalling genes elicit profound patterning effects during development. Consequently, gain-of-function genetic schemes that overexpress or misexpress such loci can identify novel candidates for functions essential for a developmental process.GAL4-Upstream Activating Sequence(UAS)-targeted regulation of gene expression inDrosophilahas allowed rapid analyses of coding sequences for potential roles in specific tissues at particular developmental stages.GAL4has also been combined with randomly mobilized transposons capable ofUAS-directed misexpression or overexpression of flanking sequences. This combination has produced a genetic screening system that can uncover novel loci refractory to standard loss of function genetic approaches, such as redundant genes. Available libraries of strains with sequenced insertion sites can allow direct correlation of phenotypes to genetic function. These techniques have also been applied to genetic interaction screening, where aGAL4driver andUAS-regulated insertion collection are combined with an extant mutant genotype. In this article, we summarize studies that have utilizedGAL4-UASoverexpression or misexpression of random loci to screen for candidates involved in specific developmental processes.