DEPARTMENT OF BIOCHEMISTRY, GENETICS AND MICROBIOLOGY DIVISION OF GENETICS GTS351 Semester test 2

Question 2 [7] Coupling is an important principle underlying eukaryotic gene expression. Formulate a definition of coupling and briefly discuss how histone modifications and the process of transcriptional elongation are coupled to premRNA splicing and polyadenylation. Your answer must relate to coupling itself – you will not get marks for discussing the processes of splicing or polyadenylation in general Question 3 [5] Answer the questions about steroid hormone receptors that follow. Refer to Fig. 3 depicting wild type estrogen and glucocorticoid nuclear steroid hormone receptors. Fig. 3. Schematic representation of estrogen hormone receptor and glucocorticoid receptor protein. AD, activation domain; DBD, DNA-binding domain. The set of genes regulated by the wild type protein is indicated on the right. 3.1. For each of the following domain swaps, explain how the glucocorticoid hormone receptor’s regulatory function will likely change through each modification: 3.1.1. Replacing the DNA binding domain of the glucocorticoid receptor with that of the estrogen receptor. 3.1.2. Replacing the hormone-binding domain of the glucocorticoid receptor with that of the estrogen receptor 3.1.3. Deletion of the hormone-binding domain of the glucocorticoid receptor. 3.2. Propose how the wild type glucocorticoid receptor activates gene expression.