Retroviruses

Question 1

Alpha Oncoviruses

Answer 1

Rous Sarcoma virus, Avian leukosis virus

Question 2

Beta Oncoviruses

Answer 2

Murine mammary tumor virus

Question 3

Gamma Oncoviruses

Answer 3

Murine leukemia virus, Feline leukemia virus

Question 4

Delta Oncoviruses

Answer 4

Human T-cell lymphotropic virus, Bovine leukemia virus

Question 5

Lentiviruses

Answer 5

HIV, Simian IV, Feline IV

Question 6

Human Endogenous Retrovirus

Answer 6

From persistant infxn fo ancient retroviruses in germline cells
K & W are active, may cause disease

Question 7

Gag proteins

Answer 7

form the capsid and include matrix, capsid, nucleocapsid and (sometimes) protease proteins

Question 8

Pol proteins

Answer 8

reverse transcriptase, ribonuclease (degrades RNA in RNA:DNA duplex) and integrase

Question 9

Long terminal repeats

Answer 9

Strong promoter/enhancer cis elements required for reverse txn, gene txn, important for splicing

Question 10

Retrovirus/HIV Life Cycle

Answer 10

Env binds CD4, CCR5, CXCR4 = entry
Cellular tRNA binds = primer
5’ end viral RNA degraded by RNase H act of RT as - strand DNA synthesized
+ strand synth & RNase H act of RT removes primer RNAs
RT extend - strand & sequences bordered by both
Final linear DNA formed and incorporated into host

Question 11

AIDS defining cancers

Answer 11

Kaposi, NHL, cervical

Question 12

Human T-cell Lymphotropic Virus

Answer 12

Delta-retrovirus that infects human T-cells and cause T-cell leukemias/lymphomas and tropical spastic paraparesis/HTLV-1- associted myelopahty, uvetitis
Southern Japan, Caribbean countries, South America, Africa, Iran
Transmission: blood, sex, breast feeding

Question 13

Adult T-cell leukemia/lymphoma

Answer 13

Enlargement of peripheral lymph nodes, skin lesion, lytic bone lesions, hypercalcemia, hepatsplenomeg, opp infxn“flower” T cells
Acute: 60%, 6 mon, hyperCa, lymphocytosis, pulm & skin
Chronic: 20%, 1-2 yr, normal Ca
Smoldering: minimal

Question 14

HTLV-1 assoc. myelopathy

Answer 14

Aka tropical spastic paraparesis
Chronic progressively paralytic disease 
Demyelination of nerves of spinal cord
Females, antibodies in blood/CSF
Tx = corticosteroids

Question 15

HIV diagnostics

Answer 15

ELISA 1st, Western blot confirms

Both detect HIV antibody

Question 16

Cytopathic Effects

Answer 16

Cause bubbling up of cells - evidence of infectious virus