Cycle 11 Workshop

Question 1

Explain:

The meaning of epigenetics

Answer 1

• “Epi-“ = “on top”
• “Genetics” = “genomic sequence”
• Tells us that it is something on top of our genomic sequence

Question 2

Define:

Epigenetics

Answer 2

The study of changes in gene expression caused by mechanisms other than changes in the underlying DNA sequence

Question 3

What is “on top” in epigenome?

Answer 3

Tags
* Methyl, acetyl groups
* Yellow blobs on top of genomic sequence

Question 4

Differentiate between genome and epigenome

Answer 4

• Genome: Consists of the DNA sequence
• Epigenome: All the tags on top of the DNA sequence

Question 5

True or False:

Tags are placed randomly on genome

Answer 5

False, tags are put on specific places?

Question 6

1. Where are methyl tags placed?
2. Where are acetyl tags placed?

Answer 6

1. SPECIFIC cytosine, part of DNA
2. SPECIFIC lysine, part of histones

Question 7

1. What is cytosine?
2. What is lysine?

Answer 7

1. A nucleobase
2. An amino acid (K, for short)

Question 8

True or False:

Epigenetic tags are dynamic

Answer 8

True, they can be turned on and off

Question 9

What does tagging in epigenome do?

Answer 9

Controls gene expression
* Like the edits in an essay
* Can tell you how to read the essay

Question 10

What is turning on/off the epigenome tags?

Answer 10

Your life experiences

Question 11

Define:

Behavioural genetics

Answer 11

The study of how epigenetic alterations induced by experience and environmental stress may affect animal behaviour

Question 12

True or False:

People undergoing similar life experiences have different epigenomes

Answer 12

False, they have similar epigenomes

Question 13

Why is DNA negatively charged?

Answer 13

Phosphate backbone

Question 13

Can monozygotic twins have different epigenomes?

Answer 13

Yes, they have the same genomes but can have different epigenomes

Question 14

What are histones positively charged?

Answer 14

Contains amino acid lysine

Question 15

True or False:

There is an attraction between histones and DNA

Answer 15

True

Question 16

What is it called when eukaryotic DNA and histone protein attract?

Answer 16

Nucleosome

Question 17

How is it determined if a gene is transcribed?

Answer 17

How tightly DNA is wrapped around the Histone Proteins

Question 18

Compare:

Euchromatin vs. Heterochromatin

Answer 18

Euchromatin
* Open form
* CAN transcribe

Heterchromatin
* Closed form
* CANNOT transcribe

Question 19

Where do methylation patterns occur?

Answer 19

Only occurs on the cytosine at CpG regions

Question 20

State enzymes involved in methylation and what results from it

Answer 20

• DNA Methyltransferase (DNMT)
• DNMT3A, DNMT3B for de novo DNA
• DNMT1 for maintenance
• INACTIVATES transcription

Question 21

State the enzymes involved in demethylation and what results from it

Answer 21

• Ten-Eleven Translocation (TET)
• ACTIVATES transcription

Question 22

True or False:

Tags are inheritable

Answer 22

True

Question 23

What does transgenerational epigenetic inheritance imply?

Answer 23

Means that tags are stable, they are maintained

Question 24

# True or False: Newly synthesized strands are initially methylated

Answer 24

False, they are initially unmethylated

Question 25

# Describe: DNA methylation process

Answer 25

1. DNMT3A and DNMT3B add methyl groups to de novo (new) DNA 2. Newly synthesized strand has non-methylated cytosines but the parent strands maintain the same methylation pattern as before replication began 3. DNMT1 recognizes hemi-methylated DNA and does methylation maintenance (methylate the cytosines in the new strand

Question 26

What is the the purpose of DNMT1?

Answer 26

Recognizes hemi-methylated sites at CpG islands

Question 27

State the enzymes involved in acetylation and what results from it

Answer 27

* Histone Acetyltransferases (HATs) * Euchromatin (open) * INCREASES transcription

Question 28

State the enzymes involved in deacetylation and what results from it

Answer 28

* Histone Deacetylases (HDACs) * Heterochromatin (close) * DECREASES transcription

Question 29

# True or False: Adding an Acetyl group to Lysine changes Lysine's charge from positive to negative

Answer 29

False, it changes the charge from positive to neutral

Question 30

What do HATs do?

Answer 30

* Acetylate lysine residues to remove positive charges * Reduces affinity between DNA and histones * Promoter is more accessible to RNA polymerase and transcription factors

Question 31

# Define: Epigenetic drift

Answer 31

Describes how the epigenome changes as we age * E.x. Twins will have the same genome at birth, but as they grow, their epigenomes will begin to differ depending on each of their lifestyles

Question 32

# True or False: Epigenome is incredibly sensitive to envrionmental stimuli

Answer 32

True

Question 33

Do early life experiences lead to inheritable, long term epigenetic effects on gene expression? Or does life experiences later in life?

Answer 33

Early in life

Question 34

What do DNMT inhibitor drugs do?

Answer 34

* Prevents DNA methylation * Allows for expression of certain genes

Question 35

How can epigenetics be utilizaed in cancer treatment?

Answer 35

* Some tumor suppressor genes in cancer cells are hypermethylated * DNMT inhibitor inhibits methylation * Thus activates tmour suppressor gene

Question 36

How do we edit epigenome with precision?

Answer 36

CRISPR with dead Cas9

Question 37

# Describe: CRISPR in epigenetics

Answer 37

* Dead Cas9 (dCas9), which can't cut DNA is used * Guide RNA recruited to target by Cas9 * dCas9 is fused to epigenetic enzyme * Results in either demethylation or methylation at targeted sites

Question 38

What produces your epigenetic clock?

Answer 38

Methylome

Question 39

What does the epigenetic clock do?

Answer 39

Used a biomarker for diseases Tells you probability that you will develop a specific disease

Question 40

# Define: Chronological age

Answer 40

Calendar age (years since birth)

Question 41

# Define: Biological age

Answer 41

Influenced by your epigenome

Question 42

# Define: Epigenetic age acceleration

Answer 42

Biological age is older than chronological age (body ages faster due to epigenome)

Question 43

# True or False: Epigenetics are more correlated with health than SNPs are

Answer 43

True