13. Gene Regulation in Eukaryotes

How are mutations in histone acetylation (HAT) genes linked to cancer?

A developmental disorder in humans called spina bifida is a neural tube defect linked to a maternal diet low in folate during pregnancy.

Should researchers be looking for mutant alleles of genes that control formation and differentiation of the neural tube?

A developmental disorder in humans called spina bifida is a neural tube defect linked to a maternal diet low in folate during pregnancy.

Does this exclude genetic mutations as a cause of this condition?

A developmental disorder in humans called spina bifida is a neural tube defect linked to a maternal diet low in folate during pregnancy.

What does this suggest about the cause of spina bifida?

Trace the relationship between the methylation status of the glucocorticoid receptor gene and the behavioral response to stress.

Because the degree of DNA methylation appears to be a relatively reliable genetic marker for some forms of cancer, researchers have explored the possibility of altering DNA methylation as a form of cancer therapy. Initial studies indicate that while hypomethylation suppresses the formation of some tumors, other tumors thrive. Why would one expect different cancers to respond differently to either hypomethylation or hypermethylation therapies?

Prader–Willi syndrome (PWS) is a genetic disorder with a clinical profile of obesity, intellectual disability, and short stature. It can be caused in several ways. Most common is a deletion on the paternal copy of chromosome 15, but it can also be caused by an epigenetic imprinting disorder and uniparental disomy, an event in which the affected child receives two copies of the maternal chromosome 15. A child with PWS comes to your clinic for a diagnosis of the molecular basis for this condition. The gel below shows the results of testing with short tandem repeats (STRs) from the region of chromosome 15 associated with the disorder.

Based on your interpretation of the data, what is the cause of PWS in this case? Explain your reasoning. 

Prader–Willi syndrome (PWS) is a genetic disorder with a clinical profile of obesity, intellectual disability, and short stature. It can be caused in several ways. Most common is a deletion on the paternal copy of chromosome 15, but it can also be caused by an epigenetic imprinting disorder and uniparental disomy, an event in which the affected child receives two copies of the maternal chromosome 15. A child with PWS comes to your clinic for a diagnosis of the molecular basis for this condition. The gel below shows the results of testing with short tandem repeats (STRs) from the region of chromosome 15 associated with the disorder.

Is this case caused by a deletion in the paternal copy of chromosome 15? Explain.

From the following table, 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?

From the following table, draw up a list of histone H3 modifications associated with gene activation. Then draw up a list of H3 modifications associated with repression.

Are these overlaps explained by different modifications?

From the following table, draw up a list of histone H3 modifications associated with gene activation. Then draw up a list of H3 modifications associated with repression.

Are there any overlaps on the lists?

Microbiologists describe the processes of transcription and translation as 'coupled' in bacteria. This term indicates that a bacterial mRNA can be undergoing transcription at the same moment it is also undergoing translation. Is coupling of transcription and translation possible in single-celled eukaryotes such as yeast? Why or why not?

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?

Amino acids are classified as positively charged, negatively charged, or electrically neutral.

How does this property of lysine allow it to interact with DNA?

Amino acids are classified as positively charged, negatively charged, or electrically neutral.

Which category includes lysine?