Question

(0 GAL4 GAL1 LexA-GAL4

Answer 1

Yeast strain Gal 4LexA & Gal 4 LexA-Gal 4 &Gal 4 UAS binds GAL4 No UAS/no binding lexAop binds LexA-Gal4

EXPLANATION: An enhancer increases the probabilities and rates of transcription of a gene, for this problem it would be necessary LacZ transcription, otherwise all strains will express it no matter which reporter sequences were transfected.

Box 1: If we introduce the plasmid that contains an enhancer DNA domain (UAS) to which the protein GAL4 binds and that later stimulates the binding of transcription factor on GAL1 promoter sequence to transcript LacZ, then as strain 1 expresses GAL 4, there will be transcription

Box2: Again there will be transcription of Lac Z as there is endogenous expression of GAL 4 in strain 2.

Box3: Yes, as there is expression of GAL4 in strain 3 as well.

Boxes 4-6: No expression in any of them as there is no enhancer sequence, no matter if the strain expresses GAL 4.

Boxe 7-9: As only the complex LexA-Gal4 can bind the enhancer sequence only the strain 3, that expresses this complex will be the one expression Lac Z.