Brainscape's Knowledge GenomeTM

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


See full index

L3 Gene Regulation > Week 5 L4: ds DNA repair > Flashcards

Week 5 L4: ds DNA repair Flashcards

1
Q

What are the 3 mechanisms for ds repair?

A

non-homologous end-joining
Single-strand annealing
Homologous recombination

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

What is the best pathway for repair?

A

homologous recombination

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

What are the flaws with non-homologous recombination and single-stranded annealing?

A

Can result with deletion in that region.

local change sin DNA.

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

What are the oncogenic markers in homologous recombination?

A

BRACA-1 BRACA-2

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

What is a feature of BRACA-1?

A

Has an affinity for various branch DNA species.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why are the changes to DNA not too important?

A

happens in somatic cells not germline cells.

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

What is the key protein in NHEJ?

A

Ku protein

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

What are the features of Ku?

A

heterodimer of 2 subunits
70/80 kD
Mediates the interaction between the 2 broken ends, acts like a splint.

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

What is the enzyme that carries out the ligation in NHEJ?

A

DNA ligase IV with XRCC4

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

Does Ku dimer make specific contacts to DNA?

A

NO

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

How does Ku bind to DNA?

A

non-specific contacts to DNA. acts like a basket to hold DNA. DNA held in splint to align broken ends

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

How can a mismatch occur in DNA bases?

A
  • Errors in DNA repair
  • From homologous recombination (2 seq being recombined are not 100% identical) in heteroduplex location there will be non-watson crick pairs.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is confusing about mismatch pairs?

A

How do we know what base is the original???

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

How do we tell parental vs newly-replicated DNA?

A

The dam methyltransferase methylate’s Bases.
when the DNA is replicated, the new bases transiently are not subject to Dam methylation. transiently a hemi-methylatd site

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

What enzyme methylates DNA?

A

dam methyltransferase

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

What can you call the newly synthesised stand?

A

hemi-methylated site

17
Q

What do we call the mismatch correction mechanism and what strand does it act upon?

A

methyl-directed mismatch correction.

on unmethylated strand

18
Q

Where are the dam sites located?

A

usually up to a kbp away from the mismatch.

19
Q

What are the first 3 proteins involved in methyl-directed mismatch correction?

A

MutS, MutH, MutL

20
Q

What is the function of MutS?

A

mismatch recognition acts as a MUTS2 dimer

21
Q

What is the function of MutH?

A

latent endonuclease, binds at dam site

22
Q

What is the function of MutL?

A

latent ATPase

mediates MutS-MutL interaction

23
Q

What activates the endonuclease activity of MutH?

A

the communication of S+L to H at the dam site

24
Q

What does H do when activated?

A

cleaves the unmethylated strand

25
Q

What is the role of the exonuclease?

A

removes DNA to allow DNA synthesis of strand to allow Pol III an ligase to repair DNA

26
Q

What are the protein’s which bind to Mismatch in DNA?

HUMANS

A

recognition: complex of MSH2 and GTPB (MSH6 in yeast)

Followed by of MLH1-PMS2 (PMS1 in yeast)

27
Q

What do mutations in the mismatch recognition site lead to?

A

HUMAN CANCER
HPNCC syndrome
germline mutations in hMSG2 and hMLH1

28
Q

What is the key protein (regulator) for upregulation of genes for DNA repair?

A

LexA

29
Q

What happens to LexA in the presence of RecA?

A

LexA cuts itself so it is no longer a repressor but a non-repressor and the repair genes are no longer repressed. upregulated

30
Q

What is the coordinated response to DNA damage called?

A

SOS response of E.coli

31
Q

What is indicative that DNA damage has occurred?

A

RecA filament

32
Q

What genes does LexA repress? (regulate)

A

umuC, UvrA, UvrB, ruvA, runB

33
Q

What are the whole cell responses to DNA damage in EUK?

A

activate repair
transcriptional regulation
cell cycle control
apoptosis or senescene

34
Q

What is the key tumour suppressor protein which coordinates the response to DNA damage?

A

p53

coordinated within cell cycle

35
Q

What is the last resort of p53?

A

APOPTOSIS

L3 Gene Regulation (14 decks)

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