Epigenetic Phenomena

Question 1

What epigenetic change happens at CpG islands?

Answer 1

methylation of cytosines

Question 2

Where are CpG islands often found?

Answer 2

close to 5’ end

Question 3

How do CpG islands relate to the expression pattern of neighboring genes?

Answer 3

CpG methlyation can shut down expression of neighboring genes

Question 4

Hypomethylation can reactivate what sort of elements?

Answer 4

transposable elements

Question 5

What enzymes introduce de novo DNA methylation?

Answer 5

DNMT 3a and 3b

Question 6

What enzyme maintains DNA methylation?

Answer 6

DNMT1

Question 7

What is the function of methylcytosine binding proteins?

Answer 7

shutdown txn by binding to metyhlated cytosines

Question 8

What proteins can MBPs directly associate with?

Answer 8

HDACs

Question 9

At what terminus do modifications of histone proteins occur?

Answer 9

N-terminus

Question 10

Methylated histones bind to what protein?

Answer 10

HP1

Question 11

HP1 proteins can bind what?

Answer 11

histone methylases

Question 12

What are chromatin barriers also known as? What is their function?

Answer 12

where cytosine methylation stops

to inhibit gene activity

Question 13

What is the function of imprinting?

Answer 13

to mark whether a chromosome has come from the mother or the father

Question 14

When does imprinting take place?

Answer 14

gametogenesis

Question 15

What is the function of XIST?

Answer 15

to inactivate the X-chromosome

Question 16

What is uniparental disomy?

Answer 16

when an individual only has maternally or paternally imprinted homologues

Question 17

What disease is an example of uniparental disomy?

Answer 17

Beckwith-Wiedemann Syndrome

Question 18

What chromosome is affected in Beckwith Wiedeman syndrome?

Answer 18

both homologues of chromosome 11 are inherited from the father

Question 19

What receptor is overexpressed in BWS?

Answer 19

insulin-like growth factor 2

Question 20

Prader Willi Syndrome results from what?

Answer 20

deletion on parental chromosome 15

Question 21

What disease results from a deletion on maternal chromosome 15?

Answer 21

Angleman

Question 22

Antibodies against what are produced during systemic lupus erythematosus? What cells are belived to be involved?

Answer 22

nuclear components

T cells

Question 23

The activity of what protein is reduced during SLE in T cells?

Answer 23

DNMT1

Question 24

HDAC inhibitors are used during what disease?

Answer 24

chronic lymphocytic leukemia

Question 25

DNMT inhibitors are used in what disease?

Answer 25

acute myeloid leukemia

Question 26

Name a DNMT inhibitor

Answer 26

5-azacytidine

Question 27

Where is epigenetic information stored?

Answer 27

methylation pattern of cytosine and covalent modification of histones

Question 28

What do writers do?

Answer 28

methylate cytosine

Question 29

What do copiers do?

Answer 29

copy methylation pattern from an old strand to a new strand of DNA

Question 30

What action do readers perform?

Answer 30

recognize methylated DNA and initiate silencing of affected chromosome regions

Question 31

What section of DNA is composed of methylated cytosines? What does this do?

Answer 31

CpG dinucleotide repeats silences that gene

Question 32

What three types of genes are often silenced by CpG dinucleotide repeats?

Answer 32

highly repetitive DNA, telomeres, centromeres

Question 33

Where are CpG island often found? Are they methylated?

Answer 33

5' UTR of genes no

Question 34

What will hypomethylation often do to transposable elements?

Answer 34

reactivate them

Question 35

How is de novo methylation introduced into an unmethylated strand of DNA?

Answer 35

DNMT 3a and 3b

Question 36

What enzyme is responsible for maintaining the pattern of methylation in DNA?

Answer 36

DNMT1

Question 37

Which strand, parent or daughter, is methylated?

Answer 37

parent

Question 38

What protein binds methylated cytosines? What is the function of this protein?

Answer 38

methylcytosine binding proteins (MBPs) to repress txn

Question 39

What is the function of H2Az?

Answer 39

increase txn of adjacent genes

Question 40

What proteins do methylated histones bind to?

Answer 40

HP1

Question 41

What happens to histones after they become de-acetylated?

Answer 41

they are often methylated

Question 42

What is the function of HP1 proteins?

Answer 42

HP1 binds to methylated histones

Question 43

What is the function of a boundary element?

Answer 43

to impede the spread of histone methylation

Question 44

What are boundary elements also known as?

Answer 44

chromatin barriers

Question 45

What are the functions of boundary elements?

Answer 45

separating active and inactive chromosomal regions

Question 46

What two biological processes are influenced by imprinting?

Answer 46

Development and maturation of gametes

Question 47

How does imprinting affect development?

Answer 47

cell-type differentiation

Question 48

What does imprinting do to DNA?

Answer 48

silences it

Question 49

When does imprinting take place?

Answer 49

gametogenesis

Question 50

Is the parent of origin re-written? When?

Answer 50

yes during gametogenesis

Question 51

How does the XIST relate to imprinting?

Answer 51

XIST designates which x-chromosome is to be inactivated

Question 52

What happens to the XIST on the x-chromosome to be inactivated?

Answer 52

it is transcribed

Question 53

What is uniparental disomy?

Answer 53

when an individual only has maternally or paternally inherited homologues of a chromosome

Question 54

Beckwith-Wiedemann Syndrome arises from what type of chromosomal aberration?

Answer 54

uniparental disomy

Question 55

How does Beckwith-Wiedemann Syndrome arise?

Answer 55

inherit two paternal homologues of chromosome 11

Question 56

Beckwith-Wiedemann Syndrome features an abundance of what receptor?

Answer 56

insulin-like growth factor 2

Question 57

Prader-Willi and Anglemann syndrome both feature what kind of aberration on what chromosome?

Answer 57

deletions on chromosome 15

Question 58

If the deletion is on maternal chromosome 15, what disease arises?

Answer 58

Anglemann

Question 59

If the deletion is on paternal chromosome 15, what disease arises?

Answer 59

Prader-Willi

Question 60

During systemic lupus erythematosus, antibodies against what are created?

Answer 60

nuclear components

Question 61

What type of immune cells are involved in SLE?

Answer 61

T-cells

Question 62

HDAC inhibitors have proven useful in what diseases?

Answer 62

chronic lymphocytic leukemia

Question 63

What does 5-azacytidine inhibit?

Answer 63

DNMT1

Question 64

Inhibition of DNMT causes what to the genome?

Answer 64

hypomethylation

Question 65

5-azacytidine has been approved in the treatment of what disease?

Answer 65

acute myeloid leukemia

Question 66

What is the role of imprinting?

Answer 66

to mark a chromosome as either paternal or maternal in origin

Question 67

When does imprinting take place?

Answer 67

gametogenesis

Question 68

What two syndromes are caused by deletions on chromosome 15?

Answer 68

Anglemann and Prader-willi

Question 69

Deletion of paternal 15 = ?

Answer 69

Prader willi

Question 70

Deletion of maternal 15 = ?

Answer 70

Anglemann

Question 71

HDAC inhibitors are effective against?

Answer 71

chronic lymphocytic leukemia

Question 72

Name a DNMT inhibitor

Answer 72

5-azacytidine

Question 73

What does 5-azacytidine do?

Answer 73

cause hypomethylation of the genome

Question 74

What has 5-azacytidine been approved for the use of?

Answer 74

acute myeloid leukemia

Question 75

What is the XIST gene?

Answer 75

X-chromosome inactivating specific transcript

Question 76

Where is XIST located?

Answer 76

X-chromosome inactivating center (XIC)

Question 77

What causes Lupus?

Answer 77

epigenetic changes in T cells

Question 78

Regarding T-cell genome, what do SLE patients show?

Answer 78

global hypomethylation

Question 79

Treating patients with what kind of drugs causes SLE-like symptoms?

Answer 79

DNMT inhibitors (5-azacytidine)