Concept explainers
The gene that encodes the enzyme called tyrosine hydroxylase is known to be activated by the CREB protein. Tyrosine hydroxylase is expressed in nerve cells and is involved in the synthesis of catecholamine, a neurotransmitter. The exposure of cells to adrenaline normally up-regulates the transcription of the tyrosine hydroxylase gene. A mutant cell was identified in which the tyrosine hydroxylase gene was not up-regulated when exposed to adrenaline. List all the possible mutations that could explain this defect. How would you explain the defect if only the tyrosine hydroxylase gene was not up-regulated by the CREB protein, whereas other genes having CREs were properly up-regulated in response to adrenaline in the mutant cell?
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Genetics: Analysis and Principles
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- The diagram below shows a closeup of regulatory proteins binding to one of the UASG elements near the GAL7, GALI0, and GALI genes, which code for the protein products needed for yeast to use the sugar galactose. The red triangle symbolizes an "effector" molecule that binds to Gal80p. In this hypothesis (which has since been shown to be incorrect), what could be happening to Gal80p when it is bound to the effector molecule that causes it to change its position and uncover the Gal4p transcriptional activation domain. Hint: think about what effector molecules do upon binding to proteins such as the the Lac repressor protein or the CAP protein. Galactose absent, glucose absent Gal80p. _Activation domain Gal4p dimer -Binding domain UASG Galactose present, glucose absent Activation domain Gal80p- Binding domain UASG For the toolbar, press ALT+F10 (PC) or ALT+FN+F10 (Mac).arrow_forwardPhorbol esters have been observed to induce the transcription of AP-1–influenced genes. Explain how this processcould occur. What are the consequences of AP-1 transcription? What role does intermittent exposure to phorbol estershave on an individual’s health?arrow_forwardwhich of the following correctly describes how protein kinase A can activate genes? A: nuclear protein kinase A is activated by cAMP to phosphorylate general transcription factors B: cytosolic protein kinase A is activated by cAMP to release the catalytic subunits, which move into the nucleus and phosphorylate CREB C: cytosolic protein kinase A is activated by cAMP to release the catalytic subunits, which move into the nucleus and phosphorylate general transcription factors D: G protein-coupled receptors may be desensitized by serine phosphorylationarrow_forward
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