Lecture 38: Eukaryotic gene expression: GAL4
1. Describe the regulatory mechanisms that allow the budding yeast, Saccharomyces cerevisiae to turn on genes for galactose utilization when galactose is available.
2. The GAL4 binding site in yeast is commonly referred to as an upstream activating sequence (UAS). Does it satisfy all of the criteria of an enhancer site? Explain your answer.
3. Describe the sequence of events that results in expression of the genes that are needed for galactose utilization in yeast. Be sure to identify the regulatory protein that galactose interacts with and the way in which it triggers the gene expression process.
4. What are three major types of transcription factors (classified in terms of their DNA-binding domains).
5. What two types of domains must a protein have to be a transcription factor? Discuss the relative specificity of each.
6. What role does the GAL80 protein play in the control of galactose utilization genes in budding yeast?
7. What effect would you expect from a mutation in the GAL4 protein that rendered it incapable of binding to the GAL80 protein?
8. What effect would you expect from a mutation in the GAL80 protein that rendered it incapable of binding galactose?
9. Describe three distinctly different examples of gene amplification.
10. What is meant by the term alternative splicing and what is its biological and genetic significance?
11. What is the importance of controlling the relative stabilities of mRNA molecules coding for different proteins?
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