Lecture 20: Neurogenesis 1

Question 1

What happens when C cells (transient amplifying cells) are exposed to epidermal growth factor?

Answer 1

revert back to B cells (radial glia-like cell)

Question 2

What happens when intermediate progenitor cells (IPCs) are exposed to Mash1?

Answer 2

become O cells (oligodendrocytes)

Question 3

What is Mash1?

Answer 3

proneural protein belonging to the neurogenin family, promotes cell fate commitment

Question 4

What is nestin?

Answer 4

acronym for neuroectodermal stem cell marker, type VI intermediate filament protein
expressed in RLG cells

Question 5

What is vimentin?

Answer 5

type III intermediate filament protein expressed on mesenchymal cells

Question 6

What is GFAP?

Answer 6

glia fibrillary acidic protein expressed on glia (most astrocytes)

Question 7

What is DCX?

Answer 7

doublecortin, microtubule-associated protein, expressed by neural precursor cells and immature neurons

Question 8

What is NeuN?

Answer 8

neuronal nuclear antigen (also called Fox- 3) marker for mature neurons

Question 9

What is calretinin / calbindin?

Answer 9

calcium binding protein used as a marker of mature neurons

Question 10

How are interneurons formed?

Answer 10

quiescent radial glia-like cell -> transient amplifying cell -> neuroblast -> migrating neuroblast and immature neuron -> interneurons

Question 11

How are neurons formed?

Answer 11

radial glia-like cell -> progenitor cells -> neuroblast -> immature neuron -> neuron

Question 12

What is Sox 2?

Answer 12

transcription factor playing key roles in mammalian development

Question 13

What is MCM2?

Answer 13

minichromosome maintenance complex component 2, marker of progenitor cells and neuroblasts

Question 14

What is neurogenesis?

Answer 14

the process by which new neurons are formed in the brain

Question 15

When does neurogenesis occur?

Answer 15

not only occurs during brain development in utero and early postnatal period but also in adulthood

Question 16

Where does neurogenesis occur in adulthood?

Answer 16

in the subventricular zone and dentate gyrus of the hippocampus

Question 17

What are new neurons derived from?

Answer 17

radial glia-like cells located in specialised niches within the brain

Question 18

In the dentate gyrus of the hippocampus what types of cells express nestin?

Answer 18

quiescent radial glia-like cells

Question 19

What type of cells in the dentate gyrus express calretinin?

Answer 19

mature neurons

Question 20

What type of cells in the dentate gyrus express calretinin?

Answer 20

mature neurons

Question 21

What is the median turnover rate of neurons within a renewing subpopulation?

Answer 21

1.75% per year during adulthood which corresponds to approximately 700 new neurons per day in each hippocampus (same in men and women)

Question 22

What is the role of Klf9?

Answer 22

functions as a negative regulator of dendritic
spines of hippocampal neurons in vitro and in vivo -> therefore overexpression of Klf9 would reduce the number of dendritic spines

Question 23

What did overexpression of Klf9 result in?

Answer 23

eliminated a subset of dendritic spines of mature dentate gyrus cells (DGCs) and decreases their activity
enhanced integration of adult-born DGCs
activated neural stem cells without affecting
olfactory bulb neurogenesis

Question 24

What did restoration of Klf9 expression to physiological levels result in?

Answer 24

restored dendritic spines and reverted levels of neurogenesis to steady state

Question 25

What does elimination of spines in mature DGCs result in?

Answer 25

increased survival of adult-born DGCs

Question 26

What does enhanced integration of adult-born DGCs result in?

Answer 26

re-organises adult-born DGC local afferent connectivity and promotes global remapping in the DG

Question 27

What did rejuvenation of the DG by enhancing integration of adult-born DGCs result in?

Answer 27

enhanced memory precision