Lecture 9

Question 1

Retinoblastoma

Answer 1

Cancer of the retinoblast (genes of the eyes)
Types:
Familial: inherit one bad gene, get 2nd bad RB gene via somatic mutation or LOH
Sporadic: get 1st bad gene via somatic mutation, get 2nd via somatic mutation or LOH

Question 2

Cell Fusion Experiments

Answer 2

Learned that some tumor forming genes are dominant (oncogenes) and some are recessive (tumor suppressor genes)

Question 3

Rb Protein pt. I

Answer 3

Properties: 105kDa, phosphoprotein, its phosphorylation varies throughout the cell cycle
Interaction with DNA Tumor Viruses: E1A, E7, and large T antigen bind to Rb protein and block its function

Question 4

Rb Protein pt. II

Answer 4

Function: to bind E2F transcription factor and prevent E2F from binding to DNA
Function regulation: hypophosphorylated Rb binds E2F while hyperphosphorylated Rb releases E2F

Question 5

CDK4/6

Answer 5

Hypophosphorylates Rb
Regulated by Cyclin D levels

Question 6

CDK2

Answer 6

Hyperphosphorylates Rb
Regulated by Cyclin E levels

Question 7

P(INK48)

Answer 7

Inhibits CDK4/6 activity and slows hypophosphorylation of Rb proteins
Binds TGIF-B to its receptor on cell surface, increasing expression of P(INK48)

Question 8

Cell Cycle Clock Regulation Disruption

Answer 8

Deletion of Rb protein
Deletion of P(INK48)
Over expression of E2F
Infection with HPV