Wk3 Control of cell differentiation

Question 1

What are key cellular processes?

Answer 1

Cell division - expansion
Cell death - elimination
Cell differentiation - specialisation

Question 2

What can a zygote differentiate into?

Answer 2

Muscle cells
Neurones
Sperm
Blood cells

Question 3

What can peripheral blood differentiate into?

Answer 3

Red cell, platelet, lymphocyte

Platelet ==> monocyte, neutrophil, eosinophil, basophil

Question 4

What are defined stages of differentiation?

Answer 4

Maintenance
Expansion
Differentiation

Question 5

Pluripotent stem cells

Answer 5

Can become any cell - gene expression keeps reducing number of options for cells before becoming fully specialised

Question 6

What makes cells different from one another?

Answer 6

• distinct functional roles
• different proteins

Proteins defining cell type features
Metabolic proteins
Structural proteins
Regulatory proteins

Question 7

Control of red blood cell and platelet differentiation

Answer 7

Erythroblast —> reticulocyte —> RBC

• a/b globins
• carbonic anhydrase: blood cells maintaining PH
• spectrin- protein specific to RBCs
• anion transporter - across membranes

Megakaryoblast—> megakaryocyte —> platelet

• thrombin receptor
• collagen receptors
• fibrinogen receptors
• granule proteins

Question 8

How to become a protein from gene?

Answer 8

1. Make primary messenger RNA copies (transcription)

2. MRNA exported from nucleus and translated into a protein in a ribosome

Question 9

What does RNA polymerase do?

Answer 9

Pulls DNA apart to form RNA - gene promoter

Question 10

What is the erythropoietin cycle?

Answer 10

Epo 
Bones
- stimulates stem cells
- rbc progenito 
RBCs
- increased O2 in carrying
- negative feedback on epo
Low O2 in proximal tube

Question 11

What does epo do?

Answer 11

Gene regulatory protein is activated and binds to regulatory DNA (regulated cascade of signals from extra cellular signals)

Provoking activating of a gene to produce another protein that binds to other regulatory regions

Epo binding to receptor:

• signalling cascade
• RBC genes turned on

Question 12

Summary of cell differentiation

Answer 12

Cell differentiation is essential:
- during development
- continuously in the adult
Differentiation occurs in multiple steps:
- from a stem cell
- through intermediate progenitors (expansion)
- to the fully mature cell

Cell phenotype is dictated it’s constituent proteins

Question 13

Protein expression summary

Answer 13

Protein expression is largely controlled by changes in gene description

The control of gene expression involves:

• multiple transcriptional regulators
• some are controlled by extra-cellular signals