Lecture 7

Question 1

What is a proto-oncogene?

Give an example

Answer 1

It is a normal gene that can become an oncogene due to mutations or upregulation of it’s expression. Int1 is a proto-oncogene

Question 2

TRUE OR FALSE

Wingless is a homolog of Int1?

Answer 2

TRUE

Question 3

What is the role of a tumour suppressor gene?

Answer 3

Tumour suppressor genes normally act to inhibit pathways, which when overactivated, cause the formation of tumours

Question 4

Why is overactivation of WNT signalling a problem in terms of tissue specific stem cells?

Answer 4

Wnt signalling can promote stem cell self-renewal. Uncontrolled self renewal is a hallmark of oncogenesis.

Question 5

Where in the crypt (of the gut) is Wnt signalling activated and what is it’s role?

Answer 5

The cells in the base of the crypt. It acts to promote self-renewal of the crypt stem cells in the niche.