Epigenetic Phenomena Flashcards Preview

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Flashcards in Epigenetic Phenomena Deck (36):
1

epigenetics

study of stable, heritable changes in gene expression taht do not inolve changes in DNA sequence

2

regulation of gene expression by epigenetics mechanisms is important for what

-imprinting during development an dgametogensis
-inactivation of X chromosome
-progression of cancer

3

what do we use as writers of epigenetic information

enzymes that methylate cytosine bases

4

what do we use as copiers of epigenetic info

enzymes that copy methylation pattern from old DNA over a new strand

5

what do we use as readers for epigenetic info

enzymes that recognize methylated stretches of DNA and initated sileicning of affected chromsomal regions.

6

what usually gets silenced by methylation

highly repetitvie DNA
telomeres
centromeres

7

where are clusters of CpG dinucleotide repeats found

CpG islands close to 5' region of genes

8

what happens if CpG islands get methylation

shuts down expression of neighboring genes

9

what happens if you ahve hypomethylation of genome

expression of genes in normally silent regions of genome

10

hypomethylation can also reactivate waht

transposable elements in normally genomic regions

11

how is the pattern of DNA methylation maintained

mitosis by DNA methyltransferase DNMT1

12

what does DNA polymerase do during DNA replication in the S phase of cell cycle

synthesizes a non-methylated strand on the methyalted template strand

13

how is the non-methylated strand methylated

by DNMT1

14

after DNA has been methylated what happens

repression of transtion by binding MBPs

15

waht do MBPs interact with

repressors of trasncription
HDACs

16

HDACs favors what

binding of histoones to DNA, leading to chromatin condensation

17

what modifications are on histones

acetylation
methylation
phosphoryaltion
ubiquination

18

what happens when you have acetylation of histones

decreases their binding affinity to DNA

19

what happens when you ahve deacetylation of histones

increases binding affinity, silences transcritpion

20

what do methylated histones bind to

HP1 proteins

21

chromosome inaction by cytosine methylation is what kind of process

self-propagating

22

imprinting of genomic regions is important in what 2 biological processes

development
matuation of gametes

23

what imprinting happens during development

cell-type specific imprint is establism

24

what imprint happens during maturation of gametes

parent of origin specific imprint is imposed on chromosomes

25

what happens to the parent of origin specific imprint during gametogenesis

it gets erased and rewritten - so you reprogram your chromosomes to make them look like yours

26

inacivation of x chromsome proceeds via waht

imprinting

27

how is X chromosome inactivated

DNA and histones are on it are methylated, shutting down expression

28

uniparental disomy

individual only has materal or pateranl imprinted homologues of chromsome

29

example of uniparental disomy

beckwith-wiedemann

30

what causes BWS

child inherits both homologues of potion of chromosome 11 from dad

31

symptoms of BWS

kideny, adrenal, liver problems, severe hypoglycemia

32

what causes prader willi

deletion on paternal chromosome 15

33

what causes angelman

deletion on maternal chromosome 15

34

hypermethylation often causes

loss of gene function

35

hypomethylation often causes waht

genomic instability

36

what causes SLE

genome o fT cells is hypomethylated, activity of DNMT1 reduced