The gene search system: its application to functional genomics in Drosophila melanogaster.

In Drosophila melanogaster, gain-of-function mutagenesis utilizing the GAL4-UAS system has been established, allowing identification of genes that may not be easily detectable by loss-of-function screening approaches. The conditional features of misexpression systems are especially useful for studying late-stage biological processes, such as those involving adult behavior or lifespan. The gene search system, incorporating a bidirectional misexpression vector, was used to screen for genes critical for longevity determination. We have identified several genes whose misexpression in adulthood extends the fly's lifespan. Phenotypic characterization of fly lines carrying a mis-expression vector, in conjunction with obtaining information about the genomic insertion sites, creates valuable resources for the systematic functional genomics in Drosophila.