Lecture 15 (nuclear oncoproteins)

Question 1

Examples of nuclear oncoproteins

Answer 1

Jun, Fos, ATF, Maf, CREB

Question 2

What is the viral ErbA oncogene?

Answer 2

A gag fusion protein

Question 3

What is ErbA?

Answer 3

Thyroid hormone receptor

Question 4

What does ErbA do?

Answer 4

Blocks differentiation of erythroblasts to erythrocytes

Question 5

Does ErbA cause transformation?

Answer 5

Not by itself, but it enhances the ability of ErbB to cause transformation

Question 6

Can the ErbA oncogene still bind the thyroid response element?

Answer 6

Yes, but has lost the ability to bind the thyroid hormone

Question 7

ErbA has sequence homology to…

Answer 7

steroid hormone receptors (particularly DNA binding region)

Question 8

Jun oncogene was isolated in __

Answer 8

ASV-17 virus

Question 9

Fos oncogene was isolated in __

Answer 9

FBJ-MuSV

Question 10

What transcriptional regulator do both jun and fos show sequence homology to?

Answer 10

GCN4

Question 11

Jun and Fos form a complex which binds DNA called the __ complex

Answer 11

AP-1

Question 12

What region of the AP-1 complex links proteins?

Answer 12

Leucine zipper region

Question 13

Jun dimerisation

Answer 13

can dimerise with itself or with fos

Question 14

True or False: Fos alone does not form dimers nor bind DNA.

Answer 14

True

Question 15

Which are more effective: jun/fos heterodimers or jun homodimers?

Answer 15

jun/fos heterodimers

Question 16

The classical AP-1 complex comprises __ and __

Answer 16

c-jun and c-fos

Question 17

Jun and fos transcriptional activators act in response to which two pathways?

Answer 17

PKC and Ras

Question 18

MAPK phosphorylating c-jun increases the ability of c-jun to…

Answer 18

interact with c-fos

Question 19

How can AP-1 activity be regulated?

Answer 19

by dimer composition, transcription, PTM, interactions with other proteins

Question 20

True or False: AP-1 has both oncogenic and anti-oncogenic effects.

Answer 20

True

Question 21

__ is upregulated by AP-1, increasing cell growth and proliferation

Answer 21

EGFR

Question 22

Functions of myc

Answer 22

• regulate gene transcription
• cell cycle progression
• cooperate with Ras mutations
• involved in chromosomal translocation in some cancers

Question 23

Myc proteins are localised in the __

Answer 23

nucleus

Question 24

Myc transcription factor functions as a __

Answer 24

complex/heterodimer

Question 25

Which signalling pathway leads to the upregulation of c-myc?

Answer 25

Oestrogen

Question 26

Myc shows homology to…

Answer 26

DNA binding regions of GCN4, fos & jun

Question 27

Myc associates with the __ protein

Answer 27

max

Question 28

How does the myc/max complex regulate transcription?

Answer 28

by binding to CACGTG sequences

Question 29

Myc/max interaction is regulated by __

Answer 29

phosphorylation

Question 30

Important event in development of Burkitt’s lymphoma in subtropical Africa

Answer 30

myc translocating into the immunoglobulin locus