And finally, our gene of the month is Swiss Cheese. As regular listeners might have come to expect, Swiss Cheese is the name of a gene mutation in fruit flies, first described in 1979. The flies start out life just fine as larvae, but then their nerve cells start to break down in the pupa and adult stages. Adult flies with a faulty Swiss Cheese gene have a characteristic pattern of holes in their brains, like their namesake food. Researchers now know that the protein encoded by Swiss Cheese is involved in controlling how supporting cells, called glial cells, wrap around nerve cells to protect them. In mutant flies, the glial cells are overactive, wrapping round the nerve cells too much and causing them to die.
Thereís a similar protein in yeast and worms, and also in mammals, where itís known as neuropathy target esterase, or NTE. Getting rid of this protein in the brain of mice leads to a similar holey appearance as in the flies, while mice lacking the gene altogether die in the womb as the placenta doesnít form properly. In humans, faults in NTE are responsible for a type of hereditary motor neurone disease, and itís also the main target of organophosphate pesticide chemicals. But the actual function of Swiss Cheese, or NTE, still needs to be completely figured out, and researchers are working to fill in the, err, holes.