Soon after the discovery of nerve growth factor (NGF), researchers injected newborn mice with rabbit antiserum (i.e. serum that contains antibodies) against NGF. They observed massive nerve cell death compared to appropriate control injections. Up to 99% of the neurons in some parts of the developing peripheral nervous system died after about a week of daily injections. These results suggest that ...
A) NGF signaling sensitizes developing nerve cells to apoptotic signals.
B) developing neurons undergo apoptosis in the presence of rabbit proteins.
C) developing neurons require NGF for apoptosis.
D) developing neurons undergo cell death in the absence of NGF.
E) NGF signaling is sufficient for survival of the developing neurons.

Question

Quizplus · Accepted Answer

The antiserum injection results in the perturbation of NGF function, which is similar to knocking-down NGF using genetic techniques. The increase in cell death after injection suggests that NGF is important for nerve cell survival. We now know that the cells undergo apoptosis in the absence of the survival factor.

Soon After the Discovery of Nerve Growth Factor (NGF), Researchers