Viral Oncogenesis

Question 1

what is the process of developing tumors

Answer 1

oncogenesis

Question 2

what is the main family of DNA viruses that may contain oncogenesis viruses

Answer 2

Herpes

Question 3

what is the main family of RNA viruses that may contain oncogenic viruses

Answer 3

Retroviruses

Question 4

when do DNA viruses produce tumors

Answer 4

during non-productive infections

Question 5

true or false:
oncogenes from DNA viruses do not have cell homologs meaning they take the DNA from their cellular hosts

Answer 5

false
they do not have cell homologs meaning these DNA sequences are unique to viruses and are not derived from the host

Question 6

what is any genetic element associated with cancer induction

Answer 6

oncogene

Question 7

what are the 2 main groups of oncogenes

Answer 7

C-oncogenes
V-oncogenes

Question 8

what are way viruses can cause cancer in a host

Answer 8

1) disregulation (up or down) of a C-oncogene
2) expression of a V-oncogene

Question 9

which mechanism of oncogenecity is the direct path

Answer 9

V-oncogenes

Question 10

which mechanism of oncogenecity is an indirect path

Answer 10

C-oncogenes

Question 11

which oncogene is responsible for the introduction of new ‘transforming gene’ into the cell

Answer 11

V-oncogene

Question 12

which oncogene is responsible for the alteration of expression of pre-existing cellular genes

Answer 12

C-oncogenes

Question 13

what are the outcomes of oncogenecity

Answer 13

-loss of normal growth regulation processes
-affection of DNA repair mechanisms
-genetic instability

Question 14

which oncogene exists in normal cells and are involved in regulation of cell growth, division / differentiation, ect.

Answer 14

C-oncogenes

Question 15

what are some malfunctions proto-oncogenes can cause

Answer 15

-overproduction of growth factors
-no longer requiring growth factor binding
-factors always having to bind to their target gene promotor
-stimulation no longer needed to start growth / replication

Question 16

what are the ways in which a C-oncogene can activate/ insert into a DNA strand

Answer 16

insertional mutagenesis
transposition
gene amplification
mutation

Question 17

true or false
there is no way for a virus to downregulate a cell

Answer 17

false
viruses can downregulate tumor suppressor genes such as P53 and retinoblastoma

Question 18

what is the function of P53 and retinoblastoma

Answer 18

control the cell cycle through apoptosis and genomic stability

Question 19

which oncogene resembles and acts as a growth factor receptor and hormone receptor

Answer 19

V-oncogene

Question 20

what normally controls V-oncogenes

Answer 20

LTRs

Question 21

what is the purpose / job of an LTR

Answer 21

it acts as strong promotor

Question 22

what are some mutations V-oncogenes may undergo

Answer 22

deletions
rearrangements for protein interactions

Question 23

what are the 2 mechanisms of retrovirus replication

Answer 23

replication defective
replication competent

Question 24

which retrovirus replication does not have all necessary genes because they are carrying a V-onc instead

Answer 24

replication defective retrovirus

Question 25

what is need with the replication defective virus to help the V-onc

Answer 25

coinfection with a second virus that will provide the missing product

Question 26

which retrovirus replication can complete their infectious cycle because they are carrying all necessary genes in their genomes

Answer 26

replication competent retroviruses

Question 27

true or false: replication defective retroviruses will often need a replication competent retrovirus to assist

Answer 27

true

Question 28

true or false: retrovirus v-oncogenes are essential for replication

Answer 28

false they need help to replicate

Question 29

what are the mechanisms in which retroviruses produce tumors

Answer 29

transducing cis-activation trans-activating

Question 30

what does can cause dysregulation of an oncogene (up or down)

Answer 30

replication competent cis-activation of a c-oncogene

Question 31

what can only cause up regulation due to high levels of v-oncogene expression

Answer 31

replication defective transduction