Deck 19: Epigenetic Regulation in Eukaryotes

Question 1

In terms of overall methylation,what is the most accurate way to describe the genomes of cancer cells?

A)A few types of cancers are have hypomethylated genomes,but it is not common in most types of cancers.
B)Cancer cells have an overall hypermethylated genome compared to healthy cells.
C)A few types of cancers are have hypermethylated genomes,but it is not common in most types of cancers.
D)Cancer cells have equivalent methylated genomes compared to healthy cells.
E)Cancer cells have an overall hypomethylated genome compared to healthy cells.

Answer 1

E

Question 2

Different modification of the histone have different effects on gene expression.For instance,the ninth amino acid of histone 3 is a lysine H3K9)can be acetylated once or methylated up to three times.Which of the following is true regarding H3K9 modification?

A)If H3K9 has two methyl groups,then the gene will be activated.
B)If H3K9 has three methyl groups,then the gene will be repressed.
C)If H3K9 is acetylated,then the gene will be repressed.
D)If H3K9 has three methyl groups,it is maximally activated compared to only having one methyl group.
E)If H3K9 has a single methyl group,then the gene will be repressed.

Answer 2

B

Question 3

Long noncoding RNAs that partially overlap protein- coding genes and are transcribed in the opposite direction are best classified as________ .

A)bidirectional lncRNA genes
B)antisense lncRNA genes
C)microRNAs
D)piwi interacting RNAs
E)intronic lncRNA genes

Answer 3

antisense lncRNA genes

Question 4

In terms of epigenetics,how the promoter would be described for a gene that is not expressed in lung tissue but is expressed in heart tissue?

A)The promoters should appear the same in both types of cells,but the mRNA produced would be hypermethylated more in lung cells compared to heart cells.
B)In lung cells,the cytosines of the promoter would be hypermethylated,and would be hypomethylated in heart cells.
C)In lung cells,the guanines in the promoter would be hypomethylated,but would be hypermethylated in heart cells.
D)In lung cells,the cytosines of the promoter would be hypomethylated,and would be hypermethylated in heart cells.
E)In lung cells,the guanines in the promoter would be hypermethylated,and would be hypomethylated in heart cells.

Question 5

What is the name of the DNA region that controls the expression of a cluster of genes through methylation?

A)epimutations
B)insulators
C)imprinting control regions
D)enhancers
E)promoters

Question 6

Which of the following genotypes would most likely lead to a low birth weight and a small placenta?

A)Igf2+/Igf2+ where neither maternal nor paternal allele is mutated.
B)Igf2+/Igf2- but only in female progeny as the Igf2 gene is on the X- chromosome.
C)Igf2+/Igf2- where the mutated Igf2- allele comes from the maternal source.
D)Igf2+/Igf2- and it doesn't matter which parental source the mutated Igf2- comes from.
E)Igf2+/Igf2- where the mutated Igf2- allele comes from the paternal source.

Question 7

The sum of histone modifications and their interactions is called the________ .

A)genetic code
B)transcription code
C)protein code
D)expression code
E)histone code

Question 8

Prader- Willi PW)and Angelman syndromes AS)are imprinting disorders of the same region on chromosome 15.Normally,the genes associated with PW are________ imprinted silenced ,and the one gene associated with AS is________ imprinted silenced .

A)maternally; randomly
B)randomly; paternally
C)paternally; maternally
D)paternally; paternally
E)maternally; paternally

Question 9

Which of the following statements is the most accurate in regards to mice pups who receive less maternal nurturing?

A)As adults their brains are heavily mutated.
B)As adults they are more likely to nurture their offspring.
C)As adults they have high levels of glucocorticoid receptor expression.
D)As adults they have increased promoter methylation.
E)As adults they have increased ability to adapt to stress.

Question 10

Which DNA methyltransferase DNMT)is important in maintaining DNA methylation patterns during DNA replication?

A)DNMT1
B)DNMT3a
C)DNMT2
D)DNMT3b
E)DNMT 1 and DNMT3a

Question 11

In humans,the number of genes that are imprinted is less than 1%.These imprinted genes are usually associated with________ .

A)DNA replication
B)brain function
C)growth regulation
D)metabolic pathways
E)apoptosis

Question 12

Compare and contrast DNMT1,DNMT3a,and DNMT3b in regards to what they do,when they act,and how they affect gene transcription.

Question 13

Which of the following is the most common place to find DNA methylation?

A)on guanines when adjacent to cytosines
B)on guanines when adjacent to other guanines
C)on cytosines when adjacent to guanines
D)on cytosines when they are base paired to guanines
E)on cytosines when adjacent to other cytosines

Question 14

A particular small noncoding RNA that is linked to spermatogenesis is most likely classified as what kind of noncoding RNA?

A)short interfering RNAs
B)bidirectional lncRNAs
C)microRNAs
D)piwi- interacting RNAs
E)antisense lncRNAs

Question 15

Which of the following statements is most true regarding X- inactivation?

A)X- inactivation is caused primarily by the expression of several small noncoding RNAs sncRNA .
B)When a cell divides,the inactive X- chromosome remains inactive in the newly formed cell.
C)X- chromosomes that remain active are called Barr bodies.
D)X- inactivation is more common in males than females.
E)X- inactivation results in repressing the expression of approximately 75% of the genes on the X- chromosome.

Question 16

About 5% of those with Rubinstein- Taybi syndrome develops cancer as a result to decreased gene expression.This is directly linked to abnormal histone modification caused by a dysfunctional enzyme.What enzyme is this?

A)DNA methyltransferase DMT
B)BRCA1
C)histone deacetyltransferase HDAC
D)histone acetylase HAT
E)No enzyme could cause this as cancer is caused only by direct DNA mutations.

Question 17

All of the following are epigenetic mechanisms,EXCEPT ________ .

A)changing gene expression by changing the nucleotide sequence through mutation
B)changing gene expression by adding and removing chemical groups to histone proteins
C)changing gene expression by the use of long noncoding RNAs
D)changing gene expression by the use of small noncoding RNAs
E)changing gene expression by adding and removing methyl groups to DNA

Question 18

Which of the following is an example of genomic imprinting in humans?

A)One of the two X- chromosomes in females is randomly expressed and the other is repressed.
B)A random pattern of autosomal allele inactivation is observed.
C)Human males have only one Y- chromosome and one X- chromosome.
D)The maternal and paternal alleles of a gene pair are both expressed.
E)In some allele pairs,only the paternal sourced allele is expressed,and in others,only the maternal sourced allele is expressed.

Question 19

List the three major epigenetic mechanisms.

Question 20

________is the study of phenomena and mechanisms that cause chromosome- associated heritable changes to gene expression that are not dependent on changes in DNA sequence.

A)Mutagenesis
B)Transmission genetics
C)Epigenetics
D)Preformation
E)Population genetics

Question 21

Explain the roles of XIST and TSIX during X- inactivation in females.

Question 22

Using the histone code different histone modifications follow a particular nomenclature.Describe the histone with this code: H3K27me3 and what is the effect of this histone modification?

Question 23

Consider the genes IGF2 and H19 and the imprinting control region ICR)between them.If the paternal ICR region was mutated in such a way that it could not be methylated but the maternal ICR was not mutated,how would that effect growth? In your explanation describe the expression of IGF2 and H19 from both the maternal and paternal alleles.

Question 24

Is there a risk for epigenetic linked diseases in using artificial reproductive technologies ART)such as in vitro
fertilization?

Question 25

Even though cancer genomes are overall hypomethylated,explain why some genes are hypermethylated in cancer cells.

Question 26

Based on rat studies that show how maternal nurturing helps offspring respond better to stress propose a model to help explain why human children who are abused have a higher suicide rate.

Question 27

The data from the NIH Roadmap Epigenomics Project are classified into which five categories?

Question 28

Explain how HATs and HDACs can lead to the formation of cancer.

Question 29

Describe the four types of long noncoding RNAs lncRNA).

Question 30

What are the two goals of the NIH Roadmap Epigenomics Project?