Further Development 3.25: The GAL4-UAS System

Targeted expression of the Pax6 gene in a Drosophila non-eye imaginal disc. (A) A strain of Drosophila was constructed wherein the gene for the yeast GAL4 transcription factor was placed downstream from an enhancer sequence that normally stimulates gene expression in the imaginal discs for mouthparts. If the embryo also contains a transgene that places GAL4-binding sites upstream of the Pax6 gene, the Pax6 gene will be expressed in whichever imaginal disc the GAL4 protein is made. (B) Drosophila ommatidia (compound eyes) emerging from the mouthparts of a fruit fly in which the Pax6 gene was expressed in the labial (jaw) discs.

Targeted expression of the Pax6 gene in a Drosophila non-eye imaginal disc. (A) A strain of Drosophila was constructed wherein the gene for the yeast GAL4 transcription factor was placed downstream from an enhancer sequence that normally stimulates gene expression in the imaginal discs for mouthparts. If the embryo also contains a transgene that places GAL4-binding sites upstream of the Pax6 gene, the Pax6 gene will be expressed in whichever imaginal disc the GAL4 protein is made. (B) Drosophila ommatidia (compound eyes) emerging from the mouthparts of a fruit fly in which the Pax6 gene was expressed in the labial (jaw) discs.

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