Lecture 3 - Embryonic Stem Cell Differentiation

Question 1

Are embryonic stem cells capable of asymmetric cell division?

Answer 1

There is no evidence that ES cells can asymmetrically divide.

Question 2

Mechanism of differentiation:

[BMP, LIF, FGF]

Answer 2

• BMP not limiting
• LIF cannot fully block differentiation
• BMP diverts fate
• FGF required

Question 3

Problems with differentiation:

Answer 3

• Heterogeneity (Not all cells become neural at the same time, efficiency is never 100%, cell types differentiated to vary)
• Full mechanism still unknown

Question 4

Endoderm differentiation:

Answer 4

Endoderm is one of the three primary germ layers in the very early embryo.
Target cell types: Hepatocytes, β-cells, lung cells…

Question 5

General Concepts of Embryonic Stem Cell Differentiation:

Answer 5

Evidence suggests that ES cells differentiate in steps similar to normal development

Specialization is gradual
Germ Layer -> Tissue -> Patterning -> Organ -> Cell Type

Initial differentiation steps are fast

• Pluripotency lost rapidly (First one or two days)
• Early lineage markers arise within first week

Mature cells types are slow to emerge (some cases > 3 weeks)