New Imaging Techniques 1 Flashcards

1
Q

Optogenetics

A

uses light to control cell and animal behaviour

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2
Q

who coined name for optogenetics?

A

Karl Diesseroth in 2006

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3
Q

phototaxis

A

algae swim to or away from light

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4
Q

2 properties of algal photoxis protein channelrhodopsin

A

fluorescent and an ion channel

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5
Q

channelrhodopsin in response to blue light

A

channel opens, sodium and calcium in, nerve depolarises and fire AP

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6
Q

what is halorhodopsin?

A

light gated chloride pump found in archae

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7
Q

what activates halorhodopsin?

A

yellow light - chloride in, hyperpolarise, silence AP

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8
Q

Briefly how does optogenetics work?

A

Light sensitive protein from algae
take gene for this protein
insert DNA into specific neurons in brain
neurons fire by shining bluelight

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9
Q

Optogenetics - spatial and temporal resolutions

A

very high spatial - single cell/synapse

high temporal - msec

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10
Q

Opto-XRs

A

opsin receptor chimeras

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11
Q

What allows chimeric GPCR receptors?

A

common structure-function relationships

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12
Q

Making Opto-XRs

A

Replace intracellular loops of bovine rhodopsin with specific adrenergic or serotonin receptors

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13
Q

advantage of Opto-XRs

A

optically activate intracellular pathways recruited by these receptors eg cAMP and IP3 pathways

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14
Q

What can enhance the specificity of optogenetics?

A

pharmaoclogy

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15
Q

what is phototropin 1?

A

blue light (BL) receptor in plants which shows BL dependent kinase activation

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16
Q

What do psychiatric diseases disturb which is a limitation to optogenetics?

A

intracellular pathways requiring protein-protein interactions

17
Q

BL on phototropin 1

A

BL excited LOV2 activates kinase domains

induces protein-protein dimerisations, subsecond and subcellular resolution

18
Q

Application for light mediated intracellular protein-protein interactions

A

phototropin 1

19
Q

What can be used as a light switchable transgene for control of gene expression

A

Lighton uses light dimerisation property of vivid

20
Q

vivid

A

light oxygen voltage domain containing protein in circadian clock systems
forms light switchable gene-promoter system

21
Q

How to use Light on/vivid

A

binds promoter after BL exposure
rapidly initiate transcription of target transgene
precise spatiotemporal control of genes in a cell type types specific fashion

22
Q

2 therapeutic uses of optogenetics

A

pain

vision

23
Q

pain - optogenetics

A

light sensitive opsins in nociceptor nerve endings
blue light - react to pain, yellow light blocks
also blocks pain perception in chronic pain

24
Q

vision - optogenetics

A

channel rhodopsin to transfect RGC blinded by retinitis pigmentosa
active light responsive ganglion cells

25
Cajal
nobel prize 1906, silver nitrate staining in histology nervous system structure discovered synapses and growth cones
26
connectome project
map entire connections of human brain | started 2010
27
brainbow and connectome project
markers to differentiate between same types of cells | brainbow generated array of fluorescent markers which label each neuron
28
which system does brainbow use?
cre loxP
29
where is cre from?
bacteriophage P1
30
how many fluorescent transgenes does brainbow use?
3/4
31
RGC projection
thalamus to cortex
32
1st week of life - how many RGC inputs does 1 thalamic cell recieve? by week 3? what is this called?
20 to 1 1 to 1 activity dependent synapse withdrawl
33
brainbow and RGC synapse withdrawl
clusters of retinal terminal - label each cell complex retinothalamic synapses synapses not withdrawn - convergence persists on thalamic relay cells