Similar to the domain swapping experiments discussed in chapter 19, you create either truncated versions or hybrid versions of proteins containing domains from the eukaryotic activator gal4 and/or the bacterial repressor lexa. the ability of these altered proteins to activate transcription is assayed using a reporter construct engineered by placing either the lexa or gal4 dna-binding site upstream of the lacz gene. which scenario leads to expression of the lacz gene in s. cerevisiae?

(a) a hybrid protein containing the lexa dna-binding domain fused to the gal4-activating domain is tested using a reporter that contains the lexa-binding site upstream of lacz.
(b) a truncated protein made using only the gal4 dna-binding domain is tested using a reporter that contains the lexa binding site upstream of lacz.
(c) a truncated protein made using only the gal4-activating region is tested using a reporter that contains the gal4-binding site upstream of lacz.
(d) a hybrid protein containing the lexa dna-binding domain fused to the gal4-activating region is tested using a reporter that contains the gal4-binding site upstream of lacz.