Tumour Suppressor Genes

Question 1

Activation of oncogenes may cause what to the cell cycle?

Answer 1

Overactivate it

Question 2

What would happen if tumour cells fused w/ normal cells (hybrid cells) were injected into a host?

Answer 2

Tumour will not form

Tumour phenotypes = not dominant

Question 3

Where do retinoblastoma tumour cells arise from?

Answer 3

RPE (retinal pigment epithelial) cells = A stem cell precursor from the cone cells

Question 4

What’s the difference between bilateral and unilateral retinoblastoma?

Answer 4

Bilateral = both eyes affected
Unilateral = 1 eye affected

Question 5

At what point of the cell cycle is Rb dephosphorylated?

Answer 5

M/G1

Question 6

At what point of the cell cycle is Rb hyperphosphorylated?

Answer 6

R point (G1 phase)

Question 7

Rb usually binds to what transcription factor?

Answer 7

E2F

Question 8

Is the mutated Rb gene dominant or recessive?

Answer 8

Recessive

Question 9

What possible processes that could lead to the 2nd mutation of Rb (loss of heterozygosity)?

Answer 9

Mitotic recombination
Gene conversion
Loss of chromosomal region (DNA repair)
Loss of entire chromosome (nondisjunction)