Retrovirus, Aids and tumor virus Flashcards Preview

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Flashcards in Retrovirus, Aids and tumor virus Deck (42):
1

in 1970 Baltimore and Temin discovered what

reverse transcriptase

2

in 1981 Gallo and associates discovered HTLV 1 the first what

HTLV 1 the first retrovirus in humans

3

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

the 4H club
AIDS

4

theory of HIV origin

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

5

initial infection of HIV in humans seemed to occur when

1930ish

6

retrovirus quick facts

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

7

two subfamilies of retrovirus

orthoretrovinnae
spumavirinae

8

what genus causes ASLV and RSv

alpharetrovirus

9

what genus causes MMTV

betaretrovirus

10

what genus causes MLV

gammaretrovirus

11

what genus causes HTLV1, HTLV 2, HTLV 5

deltaretrovirus

12

what genus causes HIV 1 and HIV 2

lentivirus

13

do spumaviruses causes disease in humans?

NO, they make foamy instructors inside of cells

14

retrovirus biology including family, genome, virion, replication location

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

15

where does retrovirus replicate

IN THE NUCLEUS AN EXCEPTION

16

is the genome of thE retrovirus diploid or haploid

diploid: identical copies

17

describe the proteins of retrovirus

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

18

what is the most common retrovirus nucleocapsid structure and location

D type cylindrical nucleus centrally located

19

what do simple retroviruses encode

The Gag, Pro, Pol, and Env genes

20

what do complex retroviruses encode

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

21

where does retrovirus replicate

nucleus!!

22

explain the retrovirus replication cycle

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

23

retrovirus biology transcription description

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

24

what prevents reverse transcriptase in retrovirus

low NTP levels

25

what has to occur for retrovirus infection to progress

reverse transcriptase has to occur for retrovirus infection to progress

26

when is reverse transcriptase silent

when copies between genomes are identical

27

how is retrovirus genomes integrated into host genome

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

28

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

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

29

how can retrovirus infect non dividing cells? explain this concept

thru importation - mechanism is unknown

30

is integration of virus DNA permanent

YES

31

can retrovirus DNA be passed on to offspring

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

32

can integration cause cancer

yes

33

name the integration identified oncogenes

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

34

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

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

35

What does a defective retrovirus require to make progeny

a complementary infection

36

quick facts about retrovirus and infections in humans

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

37

name 3 groups of retrovirus

slow retrovirus
cytopathic retrovirus
acute transforming viruses

38

describe slow retrovirus

Eg: leukemia
high level mutagenesis
results in tumors

39

cytopathic retroviruses

minority of retrovirus
cause tissue damage directly

40

acute transforming viruses

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

41

Describe the biology of HTLV including family

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

42

Describe HTLV transmission

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