Brainscape's Knowledge GenomeTM

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


See full index

Molecular Neuroscience > Mechanisms of brain function 2 > Flashcards

Mechanisms of brain function 2 Flashcards

0
Q

what is in situ hybridisation ?

A

using specific anti-sense probe that is labelled and binds to mRNA - using an electron microscope you can determine what is expressing it
good for spatial awareness but not as good for quantification

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

what techniques can be used to determine if mRNA is expressed ?

A

in situ hybridisation

northern blot

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

what is a northern blot ?

A

it enables precise quantification of the amount of mRNA expressed by cells
you need to run a control gene which is expressed at the same level in all the cells you are testing to enable normalisation of the mRNA results

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

what is the problem with northern blot and PCR ?

A

they dont provide spatial resolution

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

what happens to the levels of REST as the hours after ischaemia increase ?

A

the levels of REST mRNA goes up

- ischaemia causes induction of the gene

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

what happens if you have one seizure ?

A

you are more likely to have another seizure because it alters genes in the brain

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

describe the nature of DNA in our cells

A

DNA is a double helix wrapped around histone proteins to form nucleosomes
nucleosomes wrap up very tightly so they are small enough (30nm) to fit into chromosomes

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

what 2 things are important in gene expression ?

A
  • sequence of DNA is important
  • histone and nucleosomes involved in packaging -the packaging makes DNA quite inaccessible for DNA polymerase therefore you get marks on these histones which changes the way the nucleosomes packages them together
    e. g acetylation- some of the lyseine residues on the proteins become acetylated - lyseine is postively charged so its thought to interact quite tightly with DNA. CREB removes the charge to loosen the chromatin and this makes the DNA more accessible by TF
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

why is the sequence of DNA important ?

A

it determines which TF binds to which genes - these TF bind to genes to encourage or prevent other TF binding

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

what is CREB ?

A

transcription factor
binds to DNA as a homodimer or heterodimer
recognises a specific DNA sequence known as cAMP response element CRE
phosphorylation of CREB allows the binding of CBP- creb binding protein
CBP modifies chromatin to enhance gene transcription
100s of CREB target genes

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

what does CBP do ?

A

it enhances gene transcription because it is the enzyme that acetylates lyseines

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

what is the main barrier of transcription ?

A

chromatin because it is soo tightly packed

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

how can we investigate the role of CREB ?

A

homologous recombination in embryonic stem cells

  • gene knock out
  • gene knock in
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what does CREB do ?

A

it binds to cyclic AMP response element

- if you taken this element and stick it to a gene you can make that gene responsive to cAMP

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

what is homologous recombination ?

A

it modifies a specific gene in the genome

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

what do mouse mutants show about CRE sites in genes?

A

they show that CRE sites in genes are important for increased mRNA

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

what is BDNF gene important for ?

A

important in neuronal growth and development

17
Q

what is BDNF and how many promoters does it have ?

A

peptide that is secreted and binds to cell surface of neurons
- it has 4 different promoters

18
Q

what happens when CREB binds to cAMP response element ?

A

CBP bins to CREB and there are also many other TF which also bind for gene regulation and these other factors also interact with CBP

19
Q

what happened when the CREB binding site was deleted from the BDNF gene ?

A

this caused the BDNF gene to be no longer responsive to CREB
- the cAMP response element was deleted so CREB wont bind so CREB role could be determined in terms of BDNF expression

20
Q

what is another alternative to measuring mRNA levels ?

A

quantitative reverse transcriptase PCR

21
Q

what gene can the BDNF mRNA levels be normalised to ?

A

beta-tubulin mRNA levels

22
Q

what happens to the BDNF gene lacking CRE?

A

it is not induced by neuronal activity like normal

  • when promoter 4 was mutated it caused no induction
  • when just promoter 1,2 and 3 promoters were looked at there was a reduced induction of the BDNF gene
23
Q

what is an example of a reporter gene ?

A

beta galactosidase

24
Q

what is reporter gene ?

A

its a gene that we have a marker for so the gene can be monitored

25
Q

if the transcription level of the lacZ gene is regulated by CREB what can we determine from this ?

A

we can use the levels of lacZ as an indicator of the function of CREB
- to do this we need to make transgenic mice using pronuclei injection

26
Q

what does pronuclei microinjection produce?

A

conventional transgenic mice - these are easier and quicker to produce

27
Q

what is pronuclei microinjection ?

A

it is the injection of the foreign DNA directly into the mouse egg just after fertilisation

28
Q

what is immunohistochemistry equivalent to ?

A

it is the protein equivalent of in situ hybridisation

29
Q

what is the difference between immunohistochemistry and immunocytochemistry ?

A 
immunihistochemistry= uses tissue
immunocytochemistry = uses individual cells
30
Q

what happens to CRE mediated expression in response to training and give an example

A

it increases
in an experiment you want to cause the mouse to associate sound with having a shock= paired conditioning
after training them with this there is greater expression of CRE in CA1 so youve increased the fear response

31
Q

in an experiment to test association of shock with sound, APV was used to block NMDA receptors. What happens?

A

it causes the loss of the ability of the trained mouse to associate the sounds with the shock therefore this identifies NMDA receptors as being important for this response
- it is not proof bbut it shows good correlation

32
Q

what happens when the CRE regulatory element is removed from BDNF?

A

BDNF mRNA expression does not increase in response to neuronal activity

33
Q

what happens when a reporter gene is introduce into a mouse that contains CRE?

A

the mRNA expression of this reporter gene increases in response to neuronal activity

34
Q

what is CRE thought to be important for ?

A

its thought to be important for increased mRNA levels

35
Q

how can the effects of CREB be proved ?

A

by taking CREB away and seeing what happens to BDNF

36
Q

what was seen in mice lacking CREB ?

A

they showed reduced memory in response to a water maze
in fear training the knockout mice have reduced repsonse in fear memory when the time after training is increased, they are not particualrly different to wild type mice after 30mins to an hour but theey have a reduced memory 2 hours after an 24hours after

37
Q

what is CREB activity regulated by ?

A

by phosphorylation

38
Q

what does long term potentiation require ?

A

requires new mRNA synthesis

39
Q

what is the CREB required for ?

A

memory

40
Q

how many genes can CREB potentially regulated ?

A

6302 genes

Molecular Neuroscience (12 decks)

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