You are a scientist, trying to work out the biological basis for learning and memory, and things havent been progressing so well lately. You decie its time to stop simply observing animals in mazes, and do some manipulitave experimentation. Luckily your lab is full of fruit flies and the lab down the hall has a source of radioactive cesium isotope that's great for inducing mutations in DNA. You can also borrow some mice from the genetic engineers and developmental biologists at the medical center. You figure you can change the genes which code for any protein that could contribute to the cellular machinery underlying learning and memory. Or you could just create random mutant strains, find mutants that affect learning and memory , and then go back to find what those mutant genes are. But first you must figure out:

At the same time another one of your grad students has generated a seperate mutant strain that he calls "Rutabaga". These flies are dumb too, but this time the student notices a decrease in neuronal cAMP levels in these flies. What protein could Rutabaga code for? How could both increasing and decreasing cAMP levels make flies less able to learn?