Nucleoplasmin is a nuclear protein. This protein was divided into two segments and linked to the same large cytoplasmic protein,
generating two fusion proteins. After injecting these fusion proteins into a cell, one of the proteins was found in the nucleus and the other in the cytoplasm. Which of the following conclusions can be drawn from these results? a) Nucleoplasmin does not have a nuclear localization signal. b) One of the fusion proteins entered the nucleus by passive transport c) The cytoplasmic protein contains a nuclear localization signal. d) Only one of the two fusion proteins possesses a nuclear localization signal. e) Nucleoplasmin regulates its own destruction in a cell
The correct answer is option d) "Only one of the two fusion proteins possesses a nuclear localization signal".
Explanation:
A nuclear localization signal or sequence (NLS) serves as an amino acidic tag that is recognized by the cell, and the cells responds by importing the protein into the nucleus. In this example a protein was divided into two segments and was used to generate two fusion proteins. Since only one of the two proteins was found in the nucleus, we can conclude that only one of the two fusion proteins possesses a nuclear localization signal.
