Basics of gene regulation during development and cell differentiation Flashcards

1
Q

How many histones make up a nucleosome?

A

8

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2
Q

What is special about CpG parts in the genome regarding methylation?

A

If the C on one strand is methylated the C on the other strand (bound to the G) will also be methylated

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3
Q

How does methylation affect TFs?

A

It changes the consensus binding sites so some TFs wont recognise the consensus binding site

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4
Q

Which AAs can be phosphorylated?

A

Serine, threonine, tyrosine

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5
Q

What kind of mark is K4 trimethylation?

A

An active mark

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6
Q

What can methylated DNA do regarding histone methylation?

A

It can recruit enzymes that can methylate DNA

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7
Q

Which histone tail modifications result in an open chromatin conformation?

A

K4 and K16 acetylation

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8
Q

What kind of mark is acetylation of histones?

A

Active

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9
Q

What kind of histone methylation is an active mark?

A

K4 trimethylation

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10
Q

What do pioneer TFs do first?

A

Crawl along closed chromatin and search for a recognition sequence

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11
Q

What do pioneer TFs do once bound?

A

Displace the histones, opening the chromatin

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12
Q

What are some examples of pioneer TFs?

A

OCT4, MYG, SOX2, KLF4

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13
Q

What do OCT4, MYG, SOX2, KLF4 play a big role in?

A

Reprogramming the fertilised oocyte into an embryo

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14
Q

What are bivalent epigenetic features?

A

active and inactive marks on the same gene

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15
Q

What kind of cells have bivalent epigenetic features?

A

Stem cells

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16
Q

What is a result of bivalent epigenetic features?

A

silent but poised for activation

17
Q

What kind of mark is K27 trimethylation?

A

Weak silencing

18
Q

What is different between each cell at the 4 cell stage?

A

Their epigenetic state

19
Q

Where is DNA methylation concentrated?

A

Around the centromere and telomeres

20
Q

What is methylation used for near the centromere and telomere?

A

Sructural support

21
Q

What is methylation used for in areas of the chromosome that arent the centromere or telomere?

A

Gene silencing

22
Q

What are the two pronuclei?

A

The nucleus of the sperm and egg cells

23
Q

What happens to the two pronuclei before they fuse?

A

They lose all of their epigenetic marks

24
Q

What is the role of the TET enzyme?

A

Demethylating DNA

25
Q

What do TET enzymes turn methylated cytosines into?

A

hydroxymethylated cytosines (5HMC)

26
Q
A