Mice that are homozygous for a knockout of the gene for the kinesin motor
protein KIF1B die at birth. Heterozygous knockouts survive, but suffer from a
disease that is similar to some human neurological disorders. Which of the
following differences between neurons and most other cells could explain this
phenotype?
A. Nerve cells are longer than most other cells.
B. Nerve cells don't divide as often as other cells.
C. Unlike other cells, nerve cells contain many microtubules
that are not attached to a centrosome.
D. Most microtubules in nerve cells are bundled together by
either MAP2 or tau.
E. Most microtubules in neurons are less stable than
microtubules in other cell types.
