Design an experiment that uses enhancer trapping to drive the expression of a gene of interest

Question

What will be an ideal response?

Answer 1

Enhancer trap constructs include a reporter gene that is fused to a weak promoter that, by itself, is insufficient to drive expression of the reporter gene. The construct also requires a mobile element, typically a P element, which allows this basal transcription unit to be inserted into the genome. When the reporter gene is integrated near an enhancer region, the enhancer is "trapped" and the reporter gene is expressed, which allows you to identify spatial regulation by enhancers.
In E. coli, a common enhancer trap is P[lacZ], while yeast often uses a P[GAL4] enhancer trap. Enhancer trapping also uses a visible marker to help with easy identification of new insertions.
For example, the white gene, which is responsible for wild-type red eye color in Drosophila, is disrupted by an insertion event, creating a white-eyed phenotype. Drosophila also has the benefit
of having a large number of readily available fly stocks containing GAL4 insertions, which act as the "drivers." Using one of these stocks, plus a second fly stock containing a UAS DNA sequence followed by your gene of interest, you can simply cross these two lines of flies. This eliminates the need to directly clone transgenic flies with the enhancer linked to your gene and saves a lot of time and resources, making enhancer trapping a relatively easy process.