L2 - ES cells 1

Question 1

List the properties of ES cells

Answer 1

Can from all germ layer derivative
Come from ICM 
Non-transformed 
Indef prolif potential - immortal 
Stable diploid karyotype
Clonogenic 
Permissive to genetic manipulation

Question 2

What is a feeder layer?

Answer 2

A carpet of fibroblasts that are alive but not proliferating. The provide the necessary factors for SC self renewal

Question 3

Which pathways does LIF act on and what is it’s effect?

Answer 3

JAK/STAT pathway - activates to promote self renewal

ERK1/2 (MAPK pathway) - inhib to stop prolif/diff

Question 4

Is LIF sufficient to stop diff in serum free media?

Answer 4

No - cells need BMP found in serum to stop diff. BMP acts via smad to block entry into endoderm lineages. LIF stops entry into meso/ecto lineage

Question 5

What are the main differences in mouse and human ES cells?

Answer 5

Mouse 
- Dome 
- 2i (GSKb and ERK1/2) and LIF 
Human
- Flat 
- FGF2 and activin

Question 6

Does the formation of the human and mouse epiblast happen at the same time?

Answer 6

No. Mouse is post-implantation and human is pre-implantation

Question 7

What are the two types of ES cells and how do they differ?

Answer 7

ICM-LIKE (naive)
- mESC and NHSM hESC 
- Dome colonies 
- Oct4 distal enhancer 
- LIF-dependent 
EPIBLAST-LIKE 
- mEpiSC and hESC
- Flat colonies 
- Oct4 prox enhancer 
- Activin/FGF2 dependent

Question 8

Why are naive cells important?

Answer 8

Allow fundamental understanding of pluripotency
Easier to genetically modify
Have provided confirmation of human-mouse chimera