You are conducting a yeast two-hybrid experiment to discover proteins that interact with a particular protein of interest (protein X).Which of the following would be a useful step in this process?
A) Fuse X to the HIS3 promoter.
B) Fuse X to a DNA binding domain.
C) Fuse X to the complete HIS3 gene.
D) Purify X from recombinant yeast.
E) Fuse X to the complete Gal4 gene.

Question

Quizplus · Accepted Answer

Fusion of protein X to a DNA binding domain (such as Gal4) allows it to serve as the bait in the yeast two-hybrid system to identify protein-protein interactions. This choice is ideal for identifying proteins that bind to protein X. Fusion of X to the HIS3 promoter or complete HIS3 gene would not be useful for this purpose, as they are involved in the selection of positive yeast colonies rather than identifying interacting proteins. Purification of X would not help in identifying novel protein interactors, as it only identifies the protein itself. Fusion to the complete Gal4 gene is not necessary, as fusion to just the DNA binding domain is sufficient.

You Are Conducting a Yeast Two-Hybrid Experiment to Discover Proteins