Examination of the histone modifications around a gene reveals an abundance of histone H3 with lysine 27 modified with three methyl groups. Does this suggest that this gene is activated or repressed? How would your answer change if many lysine 27 residues were modified with acetyl groups?

Examination of the histone modifications around a gene reveals an abundance of histone H3 with lysine 27 modified with three methyl groups. Does this suggest that this gene is activated or repressed? How would your answer change if many lysine 27 residues were modified with acetyl groups?

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Description: Examination of the histone modifications around a gene reveals an abundance of histone H3 with lysine 27 modified with three methyl groups. Does this suggest that this gene is activated or repressed? How would your answer change if many lysine 27 res

Human Heredity: Principles and Issues (MindTap Course List)

11th Edition

ISBN:9781305251052

Author:Michael Cummings

Publisher:Michael Cummings

Chapter10: From Proteins To Phenotypes

Section: Chapter Questions

Problem 21QP: Transcriptional regulators are proteins that bind to promoters (the 5-flanking regions of genes) to...

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Transcriptional regulators are proteins that bind to promoters (the 5-flanking regions of genes) to regulate their transcription. Assume that a particular transcription regulator normally promotes transcription of gene X, a transport protein. If a mutation makes this regulator gene nonfunctional, would the resulting phenotype be similar to a mutation in gene X itself? Why or why not?
Examination of the histone modifications of a gene reveals an abundance of histone H3 with lysine 27 modified with a single methyl group. Does this suggest that this gene is activated or repressed? How would your answer change if many lysine 27 residues were modified with three methyl groups each?
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In the first figure of “DNMT3L Connects Unmethylated Lysine 4 of Histone H3 to de novo Methylation of DNA,” the authors determined that the DNMT3L protein interacts with several histone proteins. Using Figure a and b (from that paper), explain how each of the 4 histones interact with DNMT3L.
What are histone proteins, and how are their DNA binding properties regulated. Indicate if there are any modification(s) that comes on and off that regulates how tightly or loosely the Histone proteins are bound to DNA.
ATM is a kinase that phosphorylates histone H2AX in response to double-stranded DNA breaks. Which of the following scenarios would most quickly regulate ATM activity in the cell? a) Adding silencing methyl groups to cytosines in the Atm gene b) Modifying the histone code for the Atm gene c) Increasing expression of a miRNA specific for the Atm mRNA d) Activating an E3 ubiquitin ligase specific for the ATM protein
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When an injury occurs to the skin, the epithelial cells near the wound are signaled to react (by proliferating, migrating, and/or differentiating) to restore the skin in the wound. To investigate the healing process, researchers removed a small area of epithelial cells from the skin of mice, causing a wound. The researchers monitored the acetylation status of histone H4 at lysines K5, K8, and K16 on days 1, 4 and 9 after the wound was made. Cells in three regions were studied (see Figure A below): Normal epithelial cells not directly near the wound Epithelial cells adjacent to the wound The cells repopulating/repairing the wound (referred to as an “epithelial tongue” early in the process and “closed wound” later in the process) The percent of cells that were positive for H4 acetylation was recorded. The bar graph in Figure B below shows data for Days 4 and 9 for cells examined in the wound. While this experiment focused on mice, we may be able to apply the results to…
If histones are acetylated on a lysine amino acid (an epigenomic mark), are genes in this region likely to be expressed or not? Briefly, in a sentence or two, explain your answer. (Hint: In your answer explain what the DNA and chromatin structure would look like in regions with the acetylation compared to regions without).
What condition must be fulfilled in order for histone modification to be considered an epigenetic phenomenon? Does DNA methylation meet that criterion? Explain.
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