Retrovirus, Aids and tumor virus

Question 1

in 1970 Baltimore and Temin discovered what

Answer 1

reverse transcriptase

Question 2

in 1981 Gallo and associates discovered HTLV 1 the first what

Answer 2

HTLV 1 the first retrovirus in humans

Question 3

70 and 80s the ______ risk group begin dying of opportunistic infections defining a new disease of ____

Answer 3

the 4H club

AIDS

Question 4

theory of HIV origin

Answer 4

HIV evolved from simian virus in Africa and spread through human mobility
theory SIV to HIV2 to HIV1

Question 5

initial infection of HIV in humans seemed to occur when

Answer 5

1930ish

Question 6

retrovirus quick facts

Answer 6

retroviruses large diverse group
unique replication cycle
many are benign causing little impact on host cell
others cause significant disease and cancer

Question 7

two subfamilies of retrovirus

Answer 7

orthoretrovinnae

spumavirinae

Question 8

what genus causes ASLV and RSv

Answer 8

alpharetrovirus

Question 9

what genus causes MMTV

Answer 9

betaretrovirus

Question 10

what genus causes MLV

Answer 10

gammaretrovirus

Question 11

what genus causes HTLV1, HTLV 2, HTLV 5

Answer 11

deltaretrovirus

Question 12

what genus causes HIV 1 and HIV 2

Answer 12

lentivirus

Question 13

do spumaviruses causes disease in humans?

Answer 13

NO, they make foamy instructors inside of cells

Question 14

retrovirus biology including family, genome, virion, replication location

Answer 14

family: retroviridae
genome: +ssRNA
virion: enveloped
REPLICATES IN NUCLEUS

Question 15

where does retrovirus replicate

Answer 15

IN THE NUCLEUS AN EXCEPTION

Question 16

is the genome of thE retrovirus diploid or haploid

Answer 16

diploid: identical copies

Question 17

describe the proteins of retrovirus

Answer 17

reverse transcriptase- to go from RNA to DNA
integrase- inserts retrovirus into host genome DNA
protease
SP 120 and sp41 - proteins for attachment

Question 18

what is the most common retrovirus nucleocapsid structure and location

Answer 18

D type cylindrical nucleus centrally located

Question 19

what do simple retroviruses encode

Answer 19

The Gag, Pro, Pol, and Env genes

Question 20

what do complex retroviruses encode

Answer 20

Gag, Pro, Pol, Env and other genes including rev, new, lt., tat

Question 21

where does retrovirus replicate

Answer 21

nucleus!!

Question 22

explain the retrovirus replication cycle

Answer 22

attachment, entry, reverse transciptase changes sRNA genome to dsDNA
the dsDNA is then integrated into host dan making a provirus
transcription occurs from provirus
translation occurs, assembly, release and then maturation which includes protease activity

Question 23

retrovirus biology transcription description

Answer 23

uses reverse transcriptase to go from RNA to DNA. initiates once nucleocapsid is in cytoplasm needs high levels of NTPs
infection does NOT occur if reverse transcriptase can not occur

Question 24

what prevents reverse transcriptase in retrovirus

Answer 24

low NTP levels

Question 25

what has to occur for retrovirus infection to progress

Answer 25

reverse transcriptase has to occur for retrovirus infection to progress

Question 26

when is reverse transcriptase silent

Answer 26

when copies between genomes are identical

Question 27

how is retrovirus genomes integrated into host genome

Answer 27

through access of host nucleus, access during mitosis which means host cells must be dividing (but can infect non dividing cells through importation) 3 end processing of dsDNA attack target DNA nick created host repair - viral genome deficiencies can be fixed by host repair system

Question 28

can retrovirus genome be corrected once integrated into host genome? if so how?

Answer 28

yes, host cells repair systems are used to fix the retrovirus genome

Question 29

how can retrovirus infect non dividing cells? explain this concept

Answer 29

thru importation - mechanism is unknown

Question 30

is integration of virus DNA permanent

Answer 30

YES

Question 31

can retrovirus DNA be passed on to offspring

Answer 31

YES, provirus can be integrated in germ line and is called endogenous once this happens

Question 32

can integration cause cancer

Answer 32

yes

Question 33

name the integration identified oncogenes

Answer 33

transcription factors, secreted growth factors, growth factor receptors, cell signal transduction pathways

Question 34

do retroviruses make defected viruses during replication? what other virus does this commonly

Answer 34

Yes, many defective viruses are made, missing at least one protein can carry oncogenic properties Rabies often defective

Question 35

What does a defective retrovirus require to make progeny

Answer 35

a complementary infection

Question 36

quick facts about retrovirus and infections in humans

Answer 36

many are benign, usually not cytopathic, do cause viremia elicit a immune response but host can live normal lifes, virus is never eliminated

Question 37

name 3 groups of retrovirus

Answer 37

slow retrovirus cytopathic retrovirus acute transforming viruses

Question 38

describe slow retrovirus

Answer 38

Eg: leukemia high level mutagenesis results in tumors

Question 39

cytopathic retroviruses

Answer 39

minority of retrovirus | cause tissue damage directly

Question 40

acute transforming viruses

Answer 40

induce rapid tumor formation carry host genes (mitogenic, antiapoptotic) often replication defective bc host gene replace essential viral genes

Question 41

Describe the biology of HTLV including family

Answer 41

four distinct types 1, 2, 3, 4 deltaretrovirus first isolated in patient with cutaneous T cell lymphoma in late 70s millions affected worldwide

Question 42

Describe HTLV transmission

Answer 42

person to person, drug users, blood, sex (less efficient) mother to child via breastfeeding in host highly cell associated, primary spread through contact between infected and naive cells