Brainscape's Knowledge GenomeTM

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


See full index

CMB2001 > Chromatin remodelling and transcriptional repression > Flashcards

Chromatin remodelling and transcriptional repression Flashcards

1
Q

what enzymes are responsible for ‘Writing’ in the histone code

A
  • Histone acetyl transferases
  • Histone methyl transferases
  • Kinases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what enzymes are responsible for ‘Erasing’ in the histone code

A
  • Histone deacetylases
  • Demethylases
  • Phosphatases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what enzymes are responsible for ‘Reading’ in the histone code

A
  • Bromodomain proteins
  • Chromodomain proteins
  • PWWP proteins
  • PhD
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Cells have multiple remodelling complexes, all have what?

A

Snf2-related ATPase

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

name all 4 members of the SWI2/SNF2 ATPase Superfamily

A
  • SWI2/SNF2 superfamily
  • ISWI subfamily
  • CHD/Mi2 Subfamily
  • Ino80 subfamily
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

how are the 4 distint subfamily characterised

A

additional domains and architecture of the ATPase domain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What additional domain does SWI2/SNF2 have

A

Bromo

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

What additional domain does ISWI have

A

SANT

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

What additional domain does CHD/Mi2 have

A

Chromo + DNA binding

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

How is Ino80 subfamily characterised ?

A

it has two ATPase domain and no additional domain

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

ATP-dependent Chromatin remodelling causes _

A

Sliding, unwrapping, eviction, spacing & histone variant exchange

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

what is the catalytic subunit of SWI/SNF

A

Snf2 (or Swi2)

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

in the presence of DNA or nucleosome, SWI/SNF hydrolyses _ ATP molecules per minute

A

1000

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

what other enzyme is Snf2 related two

A

DNA helicases

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

what is the hypothesised mechanism for Snf2

A

Thought to be a molecular motor that that uses the energy from ATP hydrolysis to track along DNA and induce torsion

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

how does Snf2 affect chromatin

A

disrupts histone-DNA interaction and movement of the nucleosome

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

which two enzymes regulate the same genes in yeast

A

SWI/SNF and the GCN5 HAT

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

HATs and ATP-dependent remodellers are commonly recruited to the same _

A

promoters

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

what is Snf2 help tether it to acetylated nucleosomes

A

Bromodomains

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

H_ & A_ function co-operatively

A

HATs & ATP-dependent remodellers

21
Q

Yeast SWI/SNF regulates _ in genral transcripton and _ in cell cycle

A
  • regulates expression of 5% of 6000 Y genes
  • Regulates 25% of genes expressed at the end of mitosis
22
Q

In terms of general transcription, Human SWI/SNF needs a number of what

A

transcriptional factors -glucocorticoid and retinoid receptor, heat shock factor and MyoD

23
Q

what role does Human SWI/SNF play in the cell cycle

A

control the cycle via interaction with Rb & cyclin E

24
Q

what role does Human SWI/SNF play in the development

A

deletion results in embryonic lethality

25
Q

what role does Human SWI/SNF play in the tumour suppresion

A

mutations are associated with a variety of
tumour types

26
Q

what are the chromatin modifying factors involved in transcriptional repression

A
  • Histone Deacetylases (HDACs)
  • ATP-dependent Remodellers
  • Histone Methylases (heterochromatin)
27
Q

where active regions of the genome are hyperacetylated, repressed regions are

A

hypoacetylated

28
Q

HDACs function as _

A

co-repressors

29
Q

How many major groups of HDACs are there

A

4

30
Q

What are the groups which contain classical HDACs and what are they dependent on

A

Class I,II,IV
Zinc

31
Q

how does Class III of HDACs differ from the others

A

Sir2 family, they require NAD as a co-factor

32
Q

give an example of of a HDAC Co-Repressor Complexes which is conserved in yeast and mammals

A

SIN3 Co-Repressor

33
Q

give an example of an ATP-dependent remodellers which commonly mediate transcriptional repression

A

The NuRD complex which belong to the Mi2/CHD family

34
Q

what are the two basic types of chromatin

A

Euchromatin & Heterochromatin

35
Q

describes Euchromatin

A

gene rich and with the potential to be transcribed

36
Q

describes heterochromatin

A

gene poor, repetitive regions, transcriptional silencing

37
Q

what are the biochemical features of heterochromatin

A

1) Hypoacetylation
2) Specific Histone H3 methylation (e.g. Lys9 & Lys27
3) Association of specific silencing factors

38
Q

Heterochromatin Protein 1 is a _ protein

A

Chromodomain

39
Q

Chromodomains often recognise and bind to which residue

A

methylated lysine

40
Q

The chromodomain of HP1 is specific for _

A

H3 Lys9me2/3

41
Q

Binding of HP1 is though to _

A

compact nucleosomal array and act as platform for the recruitment of further activities that prevent recruitment/activity of RNA pol II

42
Q

What can be used to analyse heterohromatin

A

reporter silencing assay using fisson yeast

43
Q

describe the experiment used for analysis of heterochromatin

A

Normal wild type - ade6 gene expressed white colonies
Silencing reporter strain - ade6 silence express red colonies (result from build up of a red pigment which is an adenine biosynthetic intermediate

44
Q

A mutation in gene encoding a component of heterochromatin can caused what colour colonies in Heterochromatin Analysis

A

White/pink as ade6 silencing alleviated

45
Q

what is X-chromosome inactivation

A

Female have 2 X chromosome, one of which is inactivated, this equalises the number of X-linked genes expressed in males and females

46
Q

what is the condensed structure that is seen in the nucleus of inactivated X-chrm

A

Barr Body (assembled into a specific form of heterochromatin)

47
Q

How does Inactive X (Xi) form

A
  • Xist is inactive by Tsix during early development
    -later in development Xist is upregulated which inactive Tsix
  • Xist coats chromosome and recruits H3K27 methylase, it goes on to recruit further silencing factors
48
Q

what is the difference between inactive X (Xi) and active X (Xa)

A

Xa doesn’t have Xist unregulated and there for isn’t covered and doesn’t recruit silencing factors during late development

CMB2001 (11 decks)

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