CSB332H1 Lecture Notes - Lecture 18: Neurofibrillary Tangle, Nucleus Basalis Of Meynert, Spatial Disorientation
14 May 2018
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Lecture 18(b): Extracellular Vesicles & Alzheimer’s Disease
Arc Gene:
• In the distant path, our genome was invaded with a virus that left remnants of itself within our
DNA; all our neurons have a copy of this DNA and is found conserved almost everywhere in
evolution – this virus seemed to help us remember things better
o Contextual conditioning (fear memory) is associated with LTP and leads to the
increase expression of Arc gene during learning – detected by catFISH
Experiment #1:
• When Arc gene is introduced into bacterial cells, they began to express Arc protein
o Arc protein: (1) clumped together (2) began to form viral capsids
§ Viral capsids transports the viral genetic information to infect other cells
ð Arc is associated with learning and packages its mRNA into a viral-like capsid which mirror
viral capsids seen in nature; in their physical and behavioral properties
Experiment #2:
• Repeated stimulation of motor neurons in Drosophila release EVs that contain high
concentration of Arc mRNA
o EVs were able to ‘infect’ nearby muscle cells – transfer Arc mRNA to other cells
Why Do We Care?
• Mouse neurons lacking the Arc gene (Arc-knockout) were grown in petri dishes filled with
Arc-containing vesicles or Arc capsids alone
o Vesicles and capsids were taken up by the neurons and used the Arc mRNA to produce
Arc protein themselves
• Furthermore, it was seen that the expression of Arc increased as a neuron was stimulated
ð Since this can be used to ‘deliver’ mRNA etc… it can be important in how disease spreads
(Alzheimer’s Disease) and can be used for therapy
o It can also be regulated in release in; increase stimulation = increase Arc
Document Summary
In the distant path, our genome was invaded with a virus that left remnants of itself within our. Experiment #1: when arc gene is introduced into bacterial cells, they began to express arc protein, arc protein: (1) clumped together (2) began to form viral capsids. Viral capsids transports the viral genetic information to infect other cells. Arc is associated with learning and packages its mrna into a viral-like capsid which mirror viral capsids seen in nature; in their physical and behavioral properties. Experiment #2: repeated stimulation of motor neurons in drosophila release evs that contain high concentration of arc mrna, evs were able to infect" nearby muscle cells transfer arc mrna to other cells. Why do we care: mouse neurons lacking the arc gene (arc-knockout) were grown in petri dishes filled with. Arc-containing vesicles or arc capsids alone: vesicles and capsids were taken up by the neurons and used the arc mrna to produce.
