Cell Proliferation in neural tube

Question 1

why do cells proliferate at ventricular zone?

Answer 1

local paracrine signaling factors tell cell to proliferate

Question 2

how do cells get outside of neural tube?

Answer 2

radial glial cells
-grow along with neural tube
-neurons climb up radial glia

Question 3

Do NCAM, n-cadherin, and L1 promote neuronal migration along radial glial cells?
Experiment 1: function blocking antibodies

Answer 3

-anti-NCAM
-anti-n-cadherin
-anti-L1
Resulted in no effect, neurons still migrate

Functional redundancy: all function blocking Ab together-> no effect

Question 4

Experiment 2:

Answer 4

-anything necessary for embryonic neuronal cell membrane that is necessary for neuronal glial cell interaction?
-looking for function blocking Ab that block adhesion event
-results: something is responsible for adhesion, but not NCAM, n-cadherin or L1

Question 5

Experiment 3:
(draw)

Answer 5

astrotactin was the only protein present in the supernatant that only binded to embryonic membrane proteins

Question 6

Experiment 4: is astrotactin necessary for migration of neurons along radial glia?

Answer 6

-add anti-astrotactin Ab
-results: lots of inhibition of astrotaction, little binding neuron to radial glia
-astrotaction is NECESARY for for adhesion

Question 7

Is astrotactin sufficient?

Answer 7

astrotactin knockout
-resulted in decrease association btwn neurons and glia
-decrease rate of neuronal migration

did not eliminate it ->functional redundancy

Question 8

Question 1: is n-cadherin present in developing mouse cerebellum?

Answer 8

yes

Question 9

Question 2: is astrotactin physically associated with n-cad in developing mouse cerebellum?

Answer 9

-co-immunoprecipiation with anti-astrotactin Ab
- they are associated bc the Ab drags n-cad into the pellet, making it visible on the co-immunoprecipitation

Question 10

Question 3: cells expressing astrotactin and n-cad associate with eachother?

Answer 10

-yes

Question 11

Question 4: where are astrotactin and n-cad located?

Answer 11

-double label immunoflurecence
-they are located in the cerebellum at the right time

Question 12

Question 5: is n-cad necessary for neuronal cell migration along glial cells?

Answer 12

-N-cad KO in neurons and radial glia (separately): reduction in migration
-N-cad KO in neurons and radial glia (together): large reduction in migration