Exam 1: Chapter 3 Flashcards
Neurogenesis in vertebrate starts in
neural tube
Interkinetic Nuclear Migration
Some slides during cell phase
M/G towards ventricular zone, S phase towards outside
G1
control mechanism for S phase or no S phase
Multipotent cells
progenitor can make many things
1 progenitor
5 neurons
30 glia
3H thymidine birth dating
weak signal over time, replace with BrDU
autoradiography
pyramidal>granuale
cortex inside out
old > new
What tell us what cells we want
growth factors
Invariant time table
motor neurons develop at same time period
Division trends
inside out large (inner) > small (outer) Old > new pyramidal/pukinje > granule Layer 6 > Layer 1
Q fraction
quite cell cycle, what fraction leaves cell cycle, goes up as we go along
Expansion phase
low Q fraction
Neurogenic phase
high Q fraction
Why does overall length of cell cycle increase
Lengthen G1 due to growth factor # progeny generated by v zone is lowered
___ controls proliferation
cyclins, which are intrinsic
control if cell responds to extrinsic
When cyclin pairs with cdk (kinase)
phosphorylates Rb
Rb mutation
uncontrolled proliferation of retinal cells
E2F
transcription factor
Cell cycle is inhibited by proteins
p27kip/p21
cdkIs
Stop signal for cell cycle
TGF-beta
lower Q fraction
thick cortex, lower cdkIs
higher Q fraction
thin cortex, high cdkIs
Forebrain develops from
prosomeres
Dorsoventral patterning in neural tube
shh, BMP, wnt
Cerebral cortex patterns
Emx, Pax, FGF
___ promotes granule in cerebellum
Shh
purkinje make shh. signal to granule cells
Radial Glia growth factor
GGF
Neural growth factor
NT3, FGF2 (neurotrophins)
Oligo growth factor
NT3, PDGF, IGF1
Astrocyte growth factor
EGF, CNTF, BMP
CNTF + BMP2 –> GFAP
How to make astrocytes
CNTP –> phosphorylates STAT3 –> uptake GFAP/S100
BMP helps
Hes genes repress neural
How do we make sure no astrocytes before neurons?
early unresponsive to CNTF
promotor GFAP methylated so STAT3 can’t bind
Proneural TRANSCRIPTION facotrs
Mash1, neurogenin, Olig1/2
We don’t have Ac-S, but we do have
Mash
Block notch
premature differentiation of neurons
Increase Hes-1
increase S phase
How to make oligodendrocytes
ventral part of spinal cord
Nkx2.2 + Oligo1/2
How to make motor neuron
Neurog2 + oligo1/2
KO oligo 1/2
MN don’t develop either
Radial glia/apical progenitors
new neurons migrate along them
asymmetrical division
Cajal-Retizus cells
tell migrating cells where to stop
stellate shaped
located in superficial marginal zone
IPCs/basal progenitors
continue divisions after ventricular zone
at SVZ, symmetric divide for neurons
What did noctor’s GFP expressing studies reveal?
Radial glia ARE neuronal progenitors
Most neurons in cortex are
pyramidal glutamate
GABA stellate neurons
made in medial ganglionic eminence (MGE)
make internenurons/basal ganglia
not energy efficient, but novel
Cerebellar cortex: purkinje
made in V zone
from cerebellar plate
Cerebellar cortex: granuale
mad in rhombic lip
form external granule layer
____ glia guide granule cells
Bergmann glia
Cerebellum: How to
1) purkinje
2) FGC (External Granule Layer)- use Bergmann glia
3) pukinjie –> Shh –> EGL
4) EGC –> Reelin –> Purkinje
What moves purkinje so granule can pass through?
Reelin
What allows granule cells to adhere to Bergmann glia
Astrotactin
KO Reelin,
lose organization
Reeler Mutant
decrease purkinje, not single layer
decrease granule cells, stay in EGL layer
outside in cortex
What makes Reelin?
Cajal-Retzius cells
Reelin stop/go mechanism
Dab1: migrate granuale
Cul5: inhibits Dab1, but slower, so stop and go signal
Does where reelin located matter?
pathways within cell, don’t need it in right place for migration, thought it helps
Amphibian neurogenesis post-embryonic
growth of retina confined to periphery Ciliary marginal zone (CMZ) primitive to periphery retinal progenitor cells, next to mature retina Caudal shift
Nottlebohm’s birds
males large HVC spring
Female add testosterone, increase in size
3H-thymidine and testosterone
- increase labeled neurons in HVc
- same # neurons in ventricular zone
- new neurons make in VZ but migrated
Kemperman
Environment enrichment = hippocampal neurogenesis
Goud
Learning/memory associated with hippocampal neurogenesis
stress= fewer hippocampal neurons
antidepressants increase neurogenesis
SVZ –> hippocampal, cerebellum, olfactory
What cells use chain migration
olfactory
all SVZ, no radial glia, migrate by sliding on each other
