Non-cytocidal changes in virus infected cells

Question 1

cell transformation

Answer 1

changing of normal cell into caner cell

Question 2

neoplasia

Answer 2

descriptive term that denotes an abnormal tissue overgrowth that may be either localized or disseminated

Question 3

oncology

Answer 3

study of neoplasia and neoplasms

Question 4

benign neoplasm

Answer 4

growth produced by abnormal cell proliferation that remains localized and does not invade adjacent tissue

Question 5

malignant neoplasm

Answer 5

locally invasive and may also spread to other parts of the body (metastasis)

Question 6

oncogenic viruses

Answer 6

viruses that cause or give rise to tumors

Question 7

neoplasms

Answer 7

(tumors) arise as a consequence of dysregulated growth of cells derived from a single, genetically altered progenitor cell.

Question 8

metastasis

Answer 8

spread of cancer cells from the part of the body here it started (the primary site) to other parts of the body

Question 9

proto-oncogenes

Answer 9

encode proteins that function in normal cellular growth and differentiation

Question 10

tumor-suppressor gene

Answer 10

plays a role in keeping cell division in check . encodes proteins that regulate and inhibit uncontrolled growth

Question 11

Rb protein

Answer 11

alternates between the phosphorylated state and unphosphorylated.

Question 12

what phosphorylates Rb protein

Answer 12

cyclin dependent kinases (CDKs)

Question 13

E2F

Answer 13

binds to unphosphorylated Rb protien= prevents its activity and therefore not allowing cell division to proceed from G1 to S phase
binds to phosphorylated Rb protein= releases E2F from its inhibition and allows the cell cycle to proceed

Question 14

P16

Answer 14

blocks CDK thereby preventing phosphorylation of Rb protein

Question 15

p53

Answer 15

activates the DNA repair system and stops the cell cycle at G1 checkpoint (before DNA replication) if it is not repairable it triggers apoptosis

Question 16

oncogenic viruses

Answer 16

generally have a viral DNA genome integrated into host genome, however some can replicate in sync with host genome but are not integrated

Question 17

productive infection in permissive cells

Answer 17

the virus completes its replication cycle, resulting in cell lysis

Question 18

non-productive infection in non-permissive cells

Answer 18

virus transforms the well without completing its replication cycle. viral genome is integrated into the cellular DNA, complete genome persists as an autonomously replicating plasmid (episome). host cell becomes cancerous

Question 19

papillomavirus-induced malignant cancer

Answer 19

the viral DNA is integrated into that of the host. thus, integration probably is necessary for malignant transformation

Question 20

E6 &E7

Answer 20

viral oncogenes that remain intact and cause malignant transformation
E6- blocks p53
E7 blocks Rb protein—E2F is free—cells divide

Question 21

E1A

Answer 21

in adenovirus: inhibits Rb

Question 22

E1B

Answer 22

in adenovirus: blocks p53

Question 23

acutely transforming retrovirus

Answer 23

steals proto-oncogene from host. converts proto-oncogene into oncogene, then attacks a new host cell where it can cause cancer. RNA enters host —cDNA by reverse transcriptase, DNA integrated into host genome, steals proto-oncogene from host, no longer under regulatory control—> viral mutation rapidly

Question 24

slowly transforming retrovirus

Answer 24

sits on the regulatory portion of the gene of the host that regulates the proto-oncogene activity there by disruption the activity of the proto-oncogene causing cell proliferation and cancer

Question 25

promotor

Answer 25

DNA sequence at which DNA-dep RNA polymerase binds to initiate transcription

Question 26

enhancer

Answer 26

a transcriptional regulatory sequence located some distance from the promotor; it increases the rate of initiation of transcription

Question 27

5 types of tumor antigens

Answer 27

1. excessive amounts of normal proteins (prostate specific antigens)
2. oncogen antigens (FLV, FSV, ex. FOCMA)
3. abnormal proteins due to mutation
4. onco-fetal antigens (normally regress)
5. testis/cancer antigen (specific to male germ-line)

Question 28

what are tumor antigens

Answer 28

immune system recognizes these abnormal antigens as foreign and tries to destroy the tumor cell, the antigens are not properly presented to cells of the immune system

Question 29

FOCMA

Answer 29

a tumor antigen; feline oncornavirus membrane- associated antigen; presented on cell surface of these infected cells