Epigenetic Phenomena Flashcards Preview

Biochem V > Epigenetic Phenomena > Flashcards

Flashcards in Epigenetic Phenomena Deck (79):
1

What epigenetic change happens at CpG islands?

methylation of cytosines

2

Where are CpG islands often found?

close to 5' end

3

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

CpG methlyation can shut down expression of neighboring genes

4

Hypomethylation can reactivate what sort of elements?

transposable elements

5

What enzymes introduce de novo DNA methylation?

DNMT 3a and 3b

6

What enzyme maintains DNA methylation?

DNMT1

7

What is the function of methylcytosine binding proteins?

shutdown txn by binding to metyhlated cytosines

8

What proteins can MBPs directly associate with?

HDACs

9

At what terminus do modifications of histone proteins occur?

N-terminus

10

Methylated histones bind to what protein?

HP1

11

HP1 proteins can bind what?

histone methylases

12

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

where cytosine methylation stops

to inhibit gene activity

13

What is the function of imprinting?

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

14

When does imprinting take place?

gametogenesis

15

What is the function of XIST?

to inactivate the X-chromosome

16

What is uniparental disomy?

when an individual only has maternally or paternally imprinted homologues

17

What disease is an example of uniparental disomy?

Beckwith-Wiedemann Syndrome

18

What chromosome is affected in Beckwith Wiedeman syndrome?

both homologues of chromosome 11 are inherited from the father

19

What receptor is overexpressed in BWS?

insulin-like growth factor 2

20

Prader Willi Syndrome results from what?

deletion on parental chromosome 15

21

What disease results from a deletion on maternal chromosome 15?

Angleman

22

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

nuclear components

T cells

23

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

DNMT1

24

HDAC inhibitors are used during what disease?

chronic lymphocytic leukemia

25

DNMT inhibitors are used in what disease?

acute myeloid leukemia

26

Name a DNMT inhibitor

5-azacytidine

27

Where is epigenetic information stored?

methylation pattern of cytosine and covalent modification of histones

28

What do writers do?

methylate cytosine

29

What do copiers do?

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

30

What action do readers perform?

recognize methylated DNA and initiate silencing of affected chromosome regions

31

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

CpG dinucleotide repeats

silences that gene

32

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

highly repetitive DNA, telomeres, centromeres

33

Where are CpG island often found? Are they methylated?

5' UTR of genes

no

34

What will hypomethylation often do to transposable elements?

reactivate them

35

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

DNMT 3a and 3b

36

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

DNMT1

37

Which strand, parent or daughter, is methylated?

parent

38

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

methylcytosine binding proteins (MBPs)

to repress txn

39

What is the function of H2Az?

increase txn of adjacent genes

40

What proteins do methylated histones bind to?

HP1

41

What happens to histones after they become de-acetylated?

they are often methylated

42

What is the function of HP1 proteins?

HP1 binds to methylated histones

43

What is the function of a boundary element?

to impede the spread of histone methylation

44

What are boundary elements also known as?

chromatin barriers

45

What are the functions of boundary elements?

separating active and inactive chromosomal regions

46

What two biological processes are influenced by imprinting?

Development and maturation of gametes

47

How does imprinting affect development?

cell-type differentiation

48

What does imprinting do to DNA?

silences it

49

When does imprinting take place?

gametogenesis

50

Is the parent of origin re-written? When?

yes

during gametogenesis

51

How does the XIST relate to imprinting?

XIST designates which x-chromosome is to be inactivated

52

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

it is transcribed

53

What is uniparental disomy?

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

54

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

uniparental disomy

55

How does Beckwith-Wiedemann Syndrome arise?

inherit two paternal homologues of chromosome 11

56

Beckwith-Wiedemann Syndrome features an abundance of what receptor?

insulin-like growth factor 2

57

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

deletions on chromosome 15

58

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

Anglemann

59

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

Prader-Willi

60

During systemic lupus erythematosus, antibodies against what are created?

nuclear components

61

What type of immune cells are involved in SLE?

T-cells

62

HDAC inhibitors have proven useful in what diseases?

chronic lymphocytic leukemia

63

What does 5-azacytidine inhibit?

DNMT1

64

Inhibition of DNMT causes what to the genome?

hypomethylation

65

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

acute myeloid leukemia

66

What is the role of imprinting?

to mark a chromosome as either paternal or maternal in origin

67

When does imprinting take place?

gametogenesis

68

What two syndromes are caused by deletions on chromosome 15?

Anglemann and Prader-willi

69

Deletion of paternal 15 = ?

Prader willi

70

Deletion of maternal 15 = ?

Anglemann

71

HDAC inhibitors are effective against?

chronic lymphocytic leukemia

72

Name a DNMT inhibitor

5-azacytidine

73

What does 5-azacytidine do?

cause hypomethylation of the genome

74

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

acute myeloid leukemia

75

What is the XIST gene?

X-chromosome inactivating specific transcript

76

Where is XIST located?

X-chromosome inactivating center (XIC)

77

What causes Lupus?

epigenetic changes in T cells

78

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

global hypomethylation

79

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

DNMT inhibitors (5-azacytidine)