L1 - Genes and Cell Behaviour

Question 1

What causes a restriction in potency?

Answer 1

Previously thought to be due to gene loss

Now proven to be due to differential gene activity

Question 2

Development is progressive

Answer 2

Cells gradually become committed to their fates

Question 3

How can gene expression in differentiating cells be changed?

Answer 3

Gene expression in cell 1 can be controlled by factors in cell 1
- Cell intrinsic/cell autonomous mechanisms
Gene expression in cell 1 can be controlled by factors in cell 2
- Cell extrinsic/cell non-autonomous mechanisms

Question 4

How is mammalian differentiation brought about?

Answer 4

Almost all achieved by systemic, sequential changes in gene expression brought about by interactions between nucleus and changing cytoplasmic environment
Need to understand why tissue cells do not express, all of the time, all the potentialities inherent in their genome

Question 5

What are enhancer elements?

Answer 5

Activate transcription
Far from the RNA polymerase binding site
Silencer – turn of transcription

Question 6

What are transcription factors?

Answer 6

Usually act as a complex with other proteins

Regulation of gene expression with smaller number of transcription factors

Question 7

Gene regulation

Answer 7

DNA triplet code 
mRNA 
Protein 
Cell assembly and cell function 
Network assembly and network function 
Outputs – brain, CNS, PNS, behaviour, mind

Question 8

What is differentiation?

Answer 8

The process by which cells become different from each other and acquire specialised properties

Question 9

What is differentiation governed by?

Answer 9

Governed by changes in gene expression which dictate the repertoire of protein synthesized

• Extrinsic factors - morphogens
• Intrinsic factors - transcription factors

Question 10

Proteins expressed dictate whether the cell can proliferate and migrate

Answer 10

Dictate cell type, shape, ability to form circuits, receptors complement and neurotransmitter