Chapter 18, Problem 23
Amino acids are classified as positively charged, negatively charged, or electrically neutral.
How does acetylation of lysine affect its interaction with DNA, and how is this related to the activation of gene expression?
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From the data in Table 19.3, draw up a list of histone H3 modifications associated with gene activation. Then draw up a list of H3 modifications associated with repression.
If not, how can you reconcile these differences?
Amino acids are classified as positively charged, negatively charged, or electrically neutral.
Which category includes lysine?
Amino acids are classified as positively charged, negatively charged, or electrically neutral.
How does this property of lysine allow it to interact with DNA?
A particular type of anemia in humans, called β-thalassemia, results from a severe reduction or absence of the normal β-globin chain of hemoglobin. However, the γ-globin chain, normally only expressed during fetal development, can functionally substitute for β-globin. A variety of studies have explored the use of the nucleoside 5-azacytidine for the expression of γ-globin in adult patients with β-thalassemia.
Explain why this drug may also have some adverse side effects.
A particular type of anemia in humans, called β-thalassemia, results from a severe reduction or absence of the normal β-globin chain of hemoglobin. However, the γ-globin chain, normally only expressed during fetal development, can functionally substitute for β-globin. A variety of studies have explored the use of the nucleoside 5-azacytidine for the expression of γ-globin in adult patients with β-thalassemia.
How might 5-azacytidine lead to expression of γ-globin in adult patients?
Methylation of H3K9 by itself silences genes, but if H3K4 and H4K20 are also methylated, the combination of modifications stimulates transcription. What conclusions can you draw about this?