Viral Oncogenesis Flashcards
what is the process of developing tumors
oncogenesis
what is the main family of DNA viruses that may contain oncogenesis viruses
Herpes
what is the main family of RNA viruses that may contain oncogenic viruses
Retroviruses
when do DNA viruses produce tumors
during non-productive infections
true or false:
oncogenes from DNA viruses do not have cell homologs meaning they take the DNA from their cellular hosts
false
they do not have cell homologs meaning these DNA sequences are unique to viruses and are not derived from the host
what is any genetic element associated with cancer induction
oncogene
what are the 2 main groups of oncogenes
C-oncogenes
V-oncogenes
what are way viruses can cause cancer in a host
1) disregulation (up or down) of a C-oncogene
2) expression of a V-oncogene
which mechanism of oncogenecity is the direct path
V-oncogenes
which mechanism of oncogenecity is an indirect path
C-oncogenes
which oncogene is responsible for the introduction of new ‘transforming gene’ into the cell
V-oncogene
which oncogene is responsible for the alteration of expression of pre-existing cellular genes
C-oncogenes
what are the outcomes of oncogenecity
-loss of normal growth regulation processes
-affection of DNA repair mechanisms
-genetic instability
which oncogene exists in normal cells and are involved in regulation of cell growth, division / differentiation, ect.
C-oncogenes
what are some malfunctions proto-oncogenes can cause
-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
what are the ways in which a C-oncogene can activate/ insert into a DNA strand
insertional mutagenesis
transposition
gene amplification
mutation
true or false
there is no way for a virus to downregulate a cell
false
viruses can downregulate tumor suppressor genes such as P53 and retinoblastoma
what is the function of P53 and retinoblastoma
control the cell cycle through apoptosis and genomic stability
which oncogene resembles and acts as a growth factor receptor and hormone receptor
V-oncogene
what normally controls V-oncogenes
LTRs
what is the purpose / job of an LTR
it acts as strong promotor
what are some mutations V-oncogenes may undergo
deletions
rearrangements for protein interactions
what are the 2 mechanisms of retrovirus replication
replication defective
replication competent
which retrovirus replication does not have all necessary genes because they are carrying a V-onc instead
replication defective retrovirus
what is need with the replication defective virus to help the V-onc
coinfection with a second virus that will provide the missing product
which retrovirus replication can complete their infectious cycle because they are carrying all necessary genes in their genomes
replication competent retroviruses
true or false:
replication defective retroviruses will often need a replication competent retrovirus to assist
true
true or false:
retrovirus v-oncogenes are essential for replication
false
they need help to replicate
what are the mechanisms in which retroviruses produce tumors
transducing
cis-activation
trans-activating
what does can cause dysregulation of an oncogene (up or down)
replication competent
cis-activation of a c-oncogene
what can only cause up regulation due to high levels of v-oncogene expression
replication defective
transduction
