Which of the following results provided evidence of a discrete nuclear localization signal somewhere on the nucleoplasmin protein?

A. The nucleoplasmin protein was small and easily slipped through the nuclear pore complex

B. After cleavage of the nucleoplasmin protein, only the tail segments appeared in the nucleus

C. Removing the tail from the nucleoplasmin protein allowed the core segment to enter the nucleus

D. The SRP bound only to the tail of the nucleoplasmin protein, not the core segment

Option B, After cleavage of the nucleoplasmin protein, only the tail segments appeared in the nucleus

Explanation:

Cleaving of nuclear localization signals occurs before the transportation into the nucleus. Before that it is responsible for sending nuclear protein continuously after every cell division leaving very little protein in the cytoplasm. Once the cleaving occurs, the nuclear localization signals, no more protein can be transmitted thereby leaving very little protein tail segments in the nucleus. Also the signal sequences on the proteins are removed once they are trans located.

Hence, option B is correct