Rb-1 Anti-oncogene

Question 1

Rb-1

Answer 1

Anti-oncogene essential for normal development
Acts through protein-protein interactions with TF E2F
Binds to E2F and inhibits transcription of GPG
-by HDAC and HMT —> closed chromatin structure
Normal cell: Rb1 is phosphorylated (no interaction with E2F)

Question 2

E2F

Answer 2

Stimulates growth promoting genes (c-myc)

Question 3

Uncontrolled growth of GPG if

Answer 3

Rb1 gene deleted

Rb1 binds an oncogene —> releasing it from E2F

Question 4

Rb1 and polymerase interactions

Answer 4

Pol 1 TF —> prevents mediated transcription of rRNA
Pol 2 TF E2F —> blocks transcription of pol II dependent genes
Pol III TF TFIIIB —> blocks tRNA and 5S rRNA transcription

Question 5

Interaction of p53 and Rb1

Answer 5

Through p21 (CDK) keeps Rb1 unphosphorylated
- inhibits Cell growth

Question 6

Some leukemias

Answer 6

Deletion of chromosome 13 and loss of miRNA genes = cancer

Question 7

Some ovarian cancers

Answer 7

miRNAs are down regulated (due to closed chromatin structure)

Question 8

Altered miRNA transcription

Answer 8

Transcription activated by p53 and repressed by c-myc