Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Molecular basis of disease > Epigenetics > Flashcards

Epigenetics Flashcards

1
Q

What is FGR and how frequent is it?

A

Occurs in around 5% of all pregnancies
FGR is Fetal Growth Restriction when a babys growth slows or stops in utero.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are the three causes of FGR?

A

chromosomal defects
placental insufficiency
enviroment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what enviromental factors can lead to FGR?

A
  • multiple gestation (twins, triplets)
  • smoking
  • alcohol or abusing drugs
  • maternal illness or infections
  • nutrition
  • stress
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what can FGR lead to?

A
  • babies can be stillborn
  • at risk of developing lifelong disabilities (cerebral palsy)
  • risk of developing non-communicable diseases in adult hood
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What do smaller babies have a higher risk of non-communicable disease wise?

A
  • hypertension
  • raised serum cholesterol
    -impaired glucose tolerance
  • type 2 diabetes
  • obesity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

name a study conducted to see baby weight compared to a disease?

A
  • mortality from coronary heart disease before 65 years in 15,726 men and women in hertfordshire compared to baby weight
  • correlation between smaller babies and cornonary heart disease in later life
  • due to weaker hearts as smaller
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the Dutch Hunger Winter?

A

In 1944/45 food supplies were cut off to a city in Holland. So had around 500 calories a day. Pregnant women were exposed to the famine and therefore led to smaller babies and the offspring developed cardiovascular disease and diabetes.
- altered enzymes in blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is a gene?

A

a nucleotide sequence required to direct protein synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

whats the pathway of an oocyte to a blastocyst?

A

oocyte
zygote
2-cell
4-cell
8-cell
morula
blastocyst (epiblast)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what two things will a blastocyst differentiate into?

A

fetus propa or placenta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are the 5 steps of formation of a blastocyst?

A

1) maturation
2) fertilisation
3) cleavage
4) compaction
5) caviation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what initiates de novo transcription?

A

during early cleavage, the embryonic genome is gradually switched on to initiate de novo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what regulate early on embryo development?

A

mRNA’s maternally inherited from the oocyte

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are epigenetics

A

the study of heritable changes in gene activity that occur without a change in the DNA sequence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what determines how tightly packed the DNA is within the chromosomes?

A

Histones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are epigenetic modifiers?

A

enzymes that catalyse the addition or removal of epigenetic tags

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is the epigenome?

A

the genome-wide epigentic state
all of the epigenetic modifications within the cells genome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

how many pregnancies does FGR occur in

A

5%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what are epigenetic tags?

A

DNA methylation
changes to the protein structure of the histones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what are the three most studied epigenetic mechanisms?

A

1) chemical modifications of DNA (methylation)
2) Post translation modifications of histone tails
3) histone variants

21
Q

what base does DNA methylation normally occur?

A

cytosine but only if next to the base guanine (CpG)

22
Q

what catalyses the methylation of cytosine?

A

DNA methyltransferase (Dnmt)

23
Q

what types of DNA methyltransferases are there and what are they for?

A

De-novo methylation is by Dnmt3a and Dnmt3b to set up the DNA pattern
Maintenance methylation (maintains cell division after markers attached to DNA) Dnmt1

24
Q

what is the Tet enzyme?

A

undergoes oxidation reaction to convert 5-mc into 5-hmc (adds hydroxy to methylated cytosine)
can also with DNA repair ezymes convert 5-hmc to cytosine

25
Q

what can demthylated cytosine also be turned into ?

A

thymine

26
Q

what do CpGs allow for ?

A

when methylated they allow for silencing of large regions of the genome

27
Q

what are CpG islands?

A

clustered of CpGs normally in promoter or enhancer around 7% are clustered

28
Q

what sort of cytosines are found in GRE?

A

non-methylated so rna poilymerase can make direct contact with the promoter

29
Q

what are imprinted genes?

A

genes which are methylated throughout development and they need to be methylated to control their function

30
Q

what is x inactivation?

A

due to methylation when we’ve got two X chromosomes in the female, methylation switches off the X chromosome we’re not using

31
Q

what part does methylation play in cancer?

A

methylation of the gene promoter on the site of protective genes that may protect against cell replication in cancer (can have faulty methylation)

32
Q

in terms of gene expression what is DNA methylation at CpG islands important for?

A
  • Cell-specific differences in transcription
  • Developmental differences in transcription
  • Genomic imprinting
33
Q

what two processes occur where DNA methylation is critical?

A
  • variable in different tissues and involved in regulating tissue-specificc gene expression patterns
  • permanently ‘imprinted’ therefore maintained and memorised in (nearly) all tissues
34
Q

what is disturbed methylation patterns?

A

involved in many human diseases (cancer, growth defects and behavioural disorders)

35
Q

what is erased in primordial germ cells?

A

methylation marks

36
Q

what happens in terms of methylation when fertilisation occurs?

A

demethylation of the entire genome occurs
methylation marks are removed in a pattern as the cell can distinguish between paternal and maternal which causes this process to happne in different rates

37
Q

when does remethylation occur?

A

at the blastocyst stage in a cell-type specific manner (ICM vs TE) (Inner Cell Mass vs trifecta )

38
Q

what happens during global methylation?

A

during a preimplantation embryo
- somatic and placental methylation is established
- imprinted genes withstand this fluctuation

39
Q

what can effect inutero DNA methylation

A
  • intrinsic factors
  • enviromental factors
40
Q

In imprinting what is the difference between paternal and maternal in genes?

A
  • genes that promote fetal and placental growth are maternally imprinted
  • genes that inhibit fetal and placental growth are paternally imprinted
41
Q

what is maternal imprinting due to ?

A

it limits the use of maternal resources (making sure uterus and nutrients favour the mother - paternal is opposite)

42
Q

define imprinting

A

is a process that leads to heritable silencing of a gene on one of the parental chromosomes

43
Q

what is IGF2 and why is it important?

A

Insulin-like growth factor 2 gene
- matches placental nutrient supply to fetal demand
- altered IGF2 is related to FGR

44
Q

Describe the process of IGF2 maternal

A

insulator binds maternal unmethylated ICR1, H19 gene is expressed and this blocks IGF2 expression

45
Q

decribe the process of IGF2 paternal

A

paternal methylation at ICR1 prevents CTCF binding and therefore IGF2 is expressed

46
Q

what is the importance of IGF2?

A

it is a major fetal growth factor involved in differentiation, organogenesis and metabolic regulation

47
Q

what happens if IGF2 is not methylated in the paternal copy? due to loss of imprinting at the IGF2/ICR1/H19 domain

A

causes silver-russell syndrome and therefore prenatal growth failure

48
Q

what is higher umbilical cord RXRA gene promoter methylation associated with according to Godfrey, et al.Diabetes 2011?

A
  • associated with low maternal early pregnancy carbohydrate intake and with greater childhood adiposity age 9 years

Molecular basis of disease (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions