If cells that have started mitosis are treated with nocodazole, a drug that depolymerizes microtubules, what would you expect to happen? Where would you expect Mad2 protein to be localized?
A) The cells would arrest in prometaphase; Mad2 would be localized to the spindle poles.
B) The cells would arrest in telophase; Mad2 would be localized to the spindle poles.
C) The cells would immediately enter anaphase, finish mitosis, and enter G₁; Mad2 would be localized to the spindle poles.
D) The cells would arrest in prometaphase; Mad2 would be localized to almost all kinetochores.
E) The cells would arrest in telophase; Mad2 would be localized to almost all kinetochores.

Question

Quizplus · Accepted Answer

A cell treated with nocodazole fails to assemble a functional spindle, and therefore arrests in prometaphase with the chromosomes left unattached. Mad2 is recruited to unattached kinetochores and activates the spindle assembly checkpoint, preventing the onset of anaphase.

If Cells That Have Started Mitosis Are Treated with Nocodazole