Epigenetic gene regulation

Question 1

Theories as to why genomic imprinting exists?

Answer 1

Genetic conflict, Dosage compensation, placental development, prevention of parthenogenesis

Question 2

What is genetic conflict?

Answer 2

Maternal and paternal genome seem to compete for maternal resources

Question 3

What is parthenogenesis?

Answer 3

Asexual reproduction where a female can produce a fertilised egg

Question 4

What are generally the function of imprinted genes?

Answer 4

Foetal growth regulation, metabolism regulation and behavioural regulation

Question 5

What is maternal foetal interaction?

Answer 5

Imprinted genes in the baby produce products that alter maternal resource allocation

Question 6

Examples of outcomes of maternal foetal interaction?

Answer 6

Altered transport capacity of placenta

Question 7

How does a foetus signal to the mother?

Answer 7

Producing fetal/placental hormones that modify the mothers metabolism

Question 8

Effect on mothers of a mutation in Peg3 gene?

Answer 8

Poor mother–> it is the “maternal care gene” mothers wont make nests, are indifferent to offspring. It also affects milk release in mice

Question 9

What is BAT?

Answer 9

Brown adipose tissue

Question 10

What is the haig hypothesis?

Answer 10

Mothers know that the offspring that they are carrying is theirs, but fathers arent sure if the offspring is theirs-> paternal genes are there to compete against other paternal genes to ensure that their foetus grows faster and outcompetes other potential offspring–> promotes taking of maternal resources. Mother thinks ab future pregnancies and so doesn’t want to use all materna resources

Question 11

Issue with haig parental conflict hypothesis?

Answer 11

Little proof

Question 12

Coadaptation theory of imprinting?

Answer 12

Imprinted genes act co-adaptively to optimize foetal development as well as optimising maternal provisioning and nurturing.–> paternally expressed genes are expressed in both the placenta and the hypothalamus

Question 13

Role of paternally expressed genes in haig parental conflict hypothesis?

Answer 13

Growth promoting

Question 14

Role of maternally expressed genes in haig parental conflict hypothesis?

Answer 14

Growth inhibiting

Question 15

Lighter coloured square in a TAG meaning?

Answer 15

Lower frequency of interaction between those two regions

Question 16

Overall, what does H19 regulate?

Answer 16

Growth restriction

Question 17

Three overall classes of things that are needed for epigenetic mechanisms to work properly?

Answer 17

Writers, readers, erasers

Question 18

What is an epigenetic writer?

Answer 18

Enzyme that establishes the epigenetic mark

Question 19

What is an epigenetic reader?

Answer 19

The molecules that respond to the epigenetic marks

Question 20

What is an epigenetic eraser?

Answer 20

Things that can remove epigenetic marks

Question 21

What are writers for DNA methylation?

Answer 21

DMNTs and TET enzymes

Question 22

What are writers for histone acetylation?

Answer 22

HATs (histone acetyl transferases)

Question 23

What are the erasers for histone deacetylation?

Answer 23

HDACs (histone deacetylases)

Question 24

Effect of acetylating histones?

Answer 24

Opens chromatin conformation, more easy for DNA to be bound to

Question 25

Effect of deacetylasing histones?

Answer 25

More closed chromatin conformation--> DNA is harder to access

Question 26

How does noncoding RNA help with histone acetylation?

Answer 26

Acts as a scaffold

Question 27

Where do HDACs and HATs bind?

Answer 27

Histones

Question 28

What are HDACs and HATs recruited by?

Answer 28

TFs, noncoding RNAs

Question 29

What are readers of histone acetylation called?

Answer 29

Bromodomain proteins (BRD)

Question 30

What do BRDs promote the assembly of?

Answer 30

Transcriptional complexes

Question 31

What can BRDS recruit?

Answer 31

Components involved in growth (+ve or -ve)

Question 32

What is the usual effect of DNA methylation on TFs?

Answer 32

DNA methylation usually repels TFs

Question 33

What are methyl binding proteins (MBD proteins)?

Answer 33

Proteins that can bind to methylated DNA and act as a suppressive protein

Question 34

Effect of MBDs?

Answer 34

They can prevent the TF from binding instead of the methylation

Question 35

How do MBDs prevent TFs from binding?

Answer 35

MBD can occupy the promoter region

Question 36

What kind of protein is MeCP2?

Answer 36

MBD

Question 37

What can MeCP2 do other than bind methylated DNA?

Answer 37

Recruits silencing factors (e.g. histone deacetylases, chromatin remodelers), act as a splicing regulatory regions

Question 38

Effect of MeCP2 binding to methylated exon?

Answer 38

Exon is included in the mature mRNA when it otherwise wouldn't have been

Question 39

Which chromosome is the MeCP2 gene on?

Answer 39

X

Question 40

What disease does MeCP2 gene mutations cause?

Answer 40

Rett Syndrome

Question 41

Why is epigenetic a good target for medicines?

Answer 41

Dont need to go into the genome, just tweak how it is being used