Epigentics

Question 1

What are the two important criteria of epigenetic changes?

Answer 1

Clonal and Revesible

Question 2

What are the changes in DNA sequence that are done by epigenetic?

Answer 2

NO CHANGE IN SEQUENCE

Question 3

How is the maternal and paternal alleles activity different in epigenetic in contrast to genetics?

Answer 3

Epigenetic - Paternal or Maternal

Genetics - Both on or Both off

Question 4

Epigenetic modifications can be _______ by offsprings.

Answer 4

Epigenetic modifications can be Inherited by offsprings.

Question 5

What are the examples for environmental factors that change the epigenome?

Answer 5

Infection, Smoking, Aging, Pollution, Dietary components

Question 6

Transcriptional Epigenetic mechanisms

Answer 6

DNA methylation

Chromatin Modeling

Question 7

Post-transcriptional epigenetic general mechanism-

Answer 7

NcRNA

Question 8

Post translational epigenetic general mechanism -

Answer 8

Histone Modification

Question 9

What are the targets of DNA Methylation?

Answer 9

CpG Islands

Question 10

What are the 3 important DNA methylation enzymes?

Answer 10

DNMT1 - Maintenance of methyltransferases

DNMT3A and DNMT3B - De-Novo methylatransferases

Question 11

Hypomethylated DNA - Consequence?

Answer 11

Genome Instability - Mutation or rearrangements

Question 12

Hypermethylated DNA - Consequence?

Answer 12

Promoter Silencing

Question 13

Deamination of Methylated DNA - Consequence?

Answer 13

Mutation - mCpG to TpG

Question 14

Methylated DNA with UV light radiation- Consequence?

Answer 14

Increased chance for UV-induced mutations

Question 15

Methylated DNA with carcinogens presence- Consequence?

Answer 15

Carcinogen induced mutation - bind easily to the mCpG

Question 16

PTMs of Histones

Answer 16

Acetylated
Methylation
Phosphorylation
Ubiquitinated

Question 17

What is the consequences possible from PTMs of Histones?

Answer 17

Accessibility of Chromatin changes

Question 18

What are the important targets of Histone modifications? AAs

Answer 18

K - Lysin

R - Arginine

Question 19

What are the different groups of Histone modifying proteins?

Answer 19

Erasers
Writers
Readers

Question 20

Histone code Hypothesis

Answer 20

Different combinations of histone modifications (especially next to promotor) may be very specific to the transcriptional state of that gene.

Question 21

Chromatin states

Answer 21

Active, Permissive, Repressed, Inactivated

Question 22

What are the two basic kinds of epigenetic ncRNA?

Answer 22

Long ncRNA - >200 nt

Short ncRNA - < 200 nt

Question 23

RNA interference (short ncRNA) - Prevention of Translation

Answer 23

Gene inactivation (Post-transcriptional, Dicer, RdRP) may be due to endogenous virus, transposing and retroviruses

Question 24

MicroRNA (short ncRNA) - Prevention of Translation

Answer 24

20-23 long RNA with RISC navigation to the gene is leading to mRNA degradation or inhibition of translation depending on the complementary match quality.

Question 25

LncRNA are causing prevention of (2) -

Answer 25

Transcription | Translation

Question 26

What is possible for a regulation mechanism of LncRNA with Protein?

Answer 26

All levels of gene expression regulation

Question 27

X chromosome inactivation - dose compensation

Answer 27

Equalize the expression of genes between members of different biological sexes. Barr body generation.

Question 28

XIST

Answer 28

X-inactivated specific transcript | A Long ncRNA transcribed from the X chromosome to be silenced by the same XIST

Question 29

Steps of Barr body formation

Answer 29

``` XIST expression Histone modification Late DNA replication MacroH2A incorporation DNA Methylation ```

Question 30

Types of X chromosome inactivations (XCIs)

Answer 30

Random XCI - healthy normal Skewed fortunate XCI- mostly normal Skewed unfortunate XCI - mostly mutant Male XCI - only mutant

Question 31

What is the process that allows for chromosome counting and choice of XCI?

Answer 31

Cell Division

Question 32

Autoimmunity and XCI - The connection

Answer 32

Thymocytes XCI could cause skewed expression of X linked antigens - T cell maturation alteration.

Question 33

Genomic imprinting

Answer 33

Non-equivalent expression of genes on parent of origin

Question 34

Gynogenote and Androgenote

Answer 34

Total maternal and paternal forms of fertilized egg not viable for implantation

Question 35

Prader- Willi Syndrome - causes

Answer 35

Maternal UPD Paternal deletion of 15q11-13 Wrong imprinting

Question 36

Angelman Syndrome - Causes

Answer 36

Paternal UPD Maternal deletion of 15q11-13 Wrong imprinting UBE3A mutation

Question 37

What are the imprinted genes number normal?

Answer 37

Around 100

Question 38

What is the function of the imprinted genes?

Answer 38

Growth or, and Behavior

Question 39

What are the paternal and maternal genes aim in imprinting in relation to growth (different for each)?

Answer 39

Maternal - silence growth promoting genes | Paternal - silence growth reducing genes

Question 40

What are the species that present gnomic imprinting ?

Answer 40

Mammals only

Question 41

Loss of imprinting

Answer 41

Instead of mono-allelic expression, abnormally biallelic expression or total silencing in cancer!