Paternally and maternally transmitted GAL4 transcripts contribute to UAS transgene expression in early Drosophila...

The GAL4/UAS binary system with its recent modifications provides a powerful tool to study gene function in Drosophila enabling control over the timing, tissue specificity, and magnitude of gene expression. GAL4 expression during early embryonic stages has been well determined for certain driver lines, but for some of the commonly used in Drosophila research it is unknown, or partially determined. By monitoring the developmental kinetics of GAL4 expression and transgene transcription, we show that particular GAL4 drivers transiently direct ectopic expression of UAS-linked transgenes at early stages of embryogenesis in a GAL4- dependent manner via a mechanism that involves parental transmission of Gal4 transcripts.