Chapter 16, Problem 5P

You have synthesized an “enhancerless” GFP reporter gene in which the jellyfish GFP gene is placed downstream of a basal promoter that functions in mice. You will now fuse this enhancerless reporter to the three types of sequences listed below (x–z).

a.	Which of the three types of sequences would you use for which of the three listed purposes (i–iii)? In each case, explain how the particular fusion would address the particular use.

Types of sequences fused to the reporter:

x.	random mouse genome sequences
y.	known mouse kidney-specific enhancer
z.	fragments of genomic DNA surrounding the transcribed part of a mouse gene

Uses:

i.	to identify a genes’ enhancer(s)
ii.	to express GFP tissue-specifically
iii.	to identify genes expressed in neurons
b.	Which of the sequences (x–z) would you fuse to a particular mouse gene of interest in order to express the protein product of the gene “ectopically”, that is, in a tissue in which the gene is not usually expressed? Why might you want to do this experiment in the first place?