Imagine you are investigating the case of a young man who seems not to respond t
ID: 100624 • Letter: I
Question
Imagine you are investigating the case of a young man who seems not to respond to stressful situations the same way most people do. In research studies, most people respond to videos depicting frightening situations with several measurable changes in their physiology. Each of these changes in physiology results from a change in the level of expression of one of our genes. Cortisol, our primary stress hormone, causes these changes in expression in all the relevant genes. While this particular young man has almost the same reaction as everyone else does to the videos, there is one particular aspect of the physiological response he does not exhibit. Please describe a gene mutation that could be responsible for this young man’s condition. 6. If you had a loss of function mutation in the methylated DNA binding protein MECP2, what pattern of activity (if any) would you expect to see in your imprinted genes? How does this differ (if it does) from the pattern of activity you are supposed to have in these genes? 7. If an interfering RNA interfered with the production of the transformer (Tra) protein in Drosophila (fruitflies), what ratio of male to female fruitflies would you expect to see? Why?
Explanation / Answer
1. Cortisol binds to albumin of blood during stress response. The young man is not expressing stress while watching the video that is because it has high level of cortisol hormone. That may occurs by somatic mutations in PRKACA (protein kinase A (PKA) catalytic subunit), gain-of-function mutations in CTNNB1 (-catenin) or GNAS. Therefore, there is gain of function mutation for high production of cortisol.
2. The loss of function for Methylated CpG Binding Protein 2 (MeCP2) for lesser cortisol production or impede action of its function is not possible. That is because MeCP2 has a wide range of functions including repression of gene expression, compaction of unmethylated chromatin, RNA splicing, and large-scale chromatin looping. Therefore, it is not possible for single hormone, the defection in MeCP2 will cause serious health problem.
3. If an interfering RNA interfered the production Tra protein, there only male drosophila would produce because female production needs Tra2 protein production, which occurs by RNA splicing.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.