Chapter 16, Problem 21P

A modification of the $\text{two-hybrid}$ system, called the $\text{one-hybrid}$ system, is used for identifying proteins that can bind specific DNA sequences. In this method, the DNA sequence to be tested, the bait, is fused to a TATA box to drive expression of a reporter gene. The reporter gene is often chosen to complement a mutant phenotype; for example, a HIS gene may be used in a ${\text{his}}^{\text{–}}$ mutant yeast strain. A cDNA library is constructed with the cDNA sequences translationally fused to the $\text{GAL4}$ activation domain and transformed into this yeast strain. Diagram how $\text{trans-acting}$ proteins that bind to $\text{cis-acting}$ regulatory sequences can be identified using a $\text{one-hybrid}$ screen.