Lec 10 - HIV Flashcards

1
Q

what is a lentivirus

A

chronic and deadly diseases characterized by long incubation periods

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2
Q

how did HIV-1

A

immunodeficiency virus from chimpanzees and gorillas
at some point jumped the species barrier
so is zoonotic virus

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3
Q

what is HIV-2

A

restricted to west africa
- slightly more benign than 1
- could still progress to aids
less transmiss
slower progress

HIV 2 binds less efficiently than HIV 1 with the receptor molecule CD4 on the cell surface.

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4
Q

why HIV cant be completely sterilised

A

both 1 and 2 embed their genome into the host genome as a provirus

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5
Q

what 2 diseases became common in the 1980s

A

Kaposi’s sarcoma
Pneumocystis pneumonia

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6
Q

why were haemophilliacs starting to get similar diseases in the 1980s

A

these were people getting regular blood transfusions to aid blood clotting = connection was made that it may be blood borne

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7
Q

where in the world do most live with HIV

A

eastern and southern africa

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8
Q

name the immunodominant glycoprotein that studs the virus

A

gp120

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8
Q

what is the receptor cell that gp120 binds to

A

CD4 cell

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9
Q

what protein is the capsid made from

A

p24 protein

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9
Q

what allows the p24 capsid protein to be stbailised

A

thousands of water molecules

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10
Q

how many open reading frames does hiv 1 have

A

9

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11
Q

why might alternative RNA splicing be needed in HIV1

A

needed to liberate the overlapping reading frames to be expressed

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12
Q

3 key polyproteins in HIV1

A

gag
pol
env

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13
Q

which 2 polyproteins overlap

A

gag and pol
(will either produce gag on its own OR gag and pol together,
never pol on its own)

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14
Q

what is products of gag

A

matrix
capsid
nucleocapsid

15
Q

what is products of pol

A

key enzymes:
reverse transriptase
integrase
protease

16
Q

what does the protease allow

A

cleavage of the pol and gag encoded polyproteins

17
Q

what is products of env

A

gp160
which is cleaved into Gp120 and Gp41
why tf 41 and not 40 doesnt make sense

18
Q

what is LTR portion of genome

A

LTR regions contain the promoters that trigger transcription
Viral and host trancription factors can bind here

19
Q

6 accessory proteins

A

TAT
REV
NEF
VIF
VPU
VPR

20
Q

what does TAT do

A

Trans Activated Transcription:
- binds to a sequence downstream of LTR and stimulates transcription
ALSO
- can be secreted and taken up by non-infected cells where it upregulate CCR5 and CCrX4

21
Q

what is REV

A

Regulator of Virion’s protein expression
- when REV high = RNA translated for protein synthesis
- when REV low = full length genomic RNA made available for packaging (prevents splicing so it all stays togehter)

22
Q

what is VPU

A

viral protein U
= plays a role in release of virus through plasma membrane

23
Q

what is VPR

A

viral protein R
- promotes entry of viral DNA (cDNA) into nucleus

24
Q

what process allows NEF to anchor to plasma membrane

A

myristolation

25
Q

what does NEF do

A

Negative Regulatory Factor
- binds to the CD4 causing it to be endocytosed and destroyed in lysosomes = prevents super-infection of cells
AND
- prevents MHC Class 1 being presented on the plasma membrane

26
Q

what is Apobec3g

A

a cell’s innate viral protection enzyme
= a cytosine deaminase
C–>U in viral cDNA
causing hypermutation

27
Q

what does VIF do

A

polyubiquinates ApoBec3G
causing it to be degraded in proteosomes

28
Q
A