This transcription factor was found to be downregulated in breast cancer cells. Careful sequence analysis reveals the following sequence in the N-terminus of this protein (the positions of the amino acids are indicated): Pro(1)-Pro(2)-Val (3)-Ala(4)-Arg(5)-Lys(6)-Lys(7)-Arg (8)-Lys(9)-Lys(10)-Lys(11)-Tyr(12)- Ile(13) . A construct in which amino acids 1-10 are deleted does not localize to the nucleus. However, when you fuse amino acids 1-10 to GFP, GFP remains in the cytosol.

Which of the following statements best describes the conclusion that you would draw from this experiment?
amino acids 1-10 are necessary but not sufficient to direct the protein's import into the nucleus
amino acids 1-10 are necessary and sufficient to target the protein into the nucleus
amino acids 1-10 are necessary for nuclear import of this protein because this domain associates with the GEF for the small GTPase Ran
amino acids 1-10 are sufficient for the nuclear import of this protein
amino acids 1-10 are necessary for nuclear import because they interact with the Ran GTPase