Retroviral transcriptional factors

Question 1

What alleles does the Friend strain of MLV have?

Answer 1

N-tropic infects NIH-Swiss mice
B-tropic infects Balc/c mice

Question 2

What is Fv1

Answer 2

Friend virus susceptibility factor-1

Question 3

What are the alleles of Fv1

Answer 3

Fv1-N and Fv2-N

Question 4

When is Fv1 restriction blocked

Answer 4

Before reverse transcription

Question 5

How does Fv1 block retrovirus replication

Answer 5

Binds CA, leads to a single amino acid change in CA thus altering tropism

Question 6

What does PEG do?

Answer 6

Fuse membranes

Question 7

Is it a positive or negative factor that prevents HIV replication

Answer 7

Negative

Question 8

What experiment proved that there is a negative factor preventing HIV replication in non-human primates?

Answer 8

Cell fusion experiment

Question 9

What is TRIM5-alpha

Answer 9

HIV-1 restriction factor

Question 10

Structure of TRIM5-alpha

Answer 10

Ring and B-box for auto-ubiquininylation
Coiled coil for dimerisation
SPRY domain for binding to CA

Question 11

What mutation of capsid prevents TRIM5-alpha block

Answer 11

Arg to Glu

Question 12

What does TRIM5-alpha do to HIV?

Answer 12

Targets capsid for proteasomal degradation forming a net around a capsid

Question 13

What types of TRIM5-alpha blocks HIV-1

Answer 13

Rhesus and African Green monkey

Question 14

What type of TRIM5-alpha doesn’t block HIV-1 and why

Answer 14

Human, SPRY mutation preventing interaction with HIV-1 CA

Question 15

What is Vif

Answer 15

A HIV cytoplasmic protein affecting virus particel maturation, binding to virion RNA in cytoplasm incorporated into virions

Question 16

What does Vif counteract

Answer 16

Cellular antiviral factor, APOBEC3G

Question 17

What gene do non-permissive cells express>

Answer 17

APOBEC3G, in cells like primary human T cells

Question 18

Without Vif what protein is incorporated into virus particles?

Answer 18

APOBEC3G

Question 19

What does APOBEC3G do?

Answer 19

Convert cytosines to uracil driving hypermutation, uracil in DNA leads to degradation via base exicision

Question 20

How does Vir block action of APOBEC3G?

Answer 20

Vif binds to APOBEC3G and recruits’ ubiquitin ligase complex leading to degradation by proteasome.

Question 21

Function of Vpu

Answer 21

Binds to and induces degradation of CD4 by ubiquitin-proteasome pathway - allows Env to escape trapping in the ER

Question 22

What does Vpu interact with?

Answer 22

Tetherin and directs uniquitin-dependent degradation

Question 23

In HIV-1, O, N and P what can’t Vpu antagonise?

Answer 23

Tetherin

Question 24

In cpz or gor what protein targets tetherin?

Answer 24

Neg

Question 25

What is SAHMD1 expression induced by

Answer 25

Inteferon treatment

Question 26

Where is SAHMD1 highly expressed?

Answer 26

Myeloid cells like macrophages

Question 27

What type of HIV does SAHMD1 block

Answer 27

HIV-1

Question 28

What is SAHMD1 targetted by?

Answer 28

Targets for HIV-2 Vpx protein. Vpx binds SAMHD1 and induces proteasomal degradation.

Question 29

What protein is mutated in Aicardi-Goutiere Syndrome?

Answer 29

SAMHD1

Question 30

Whare are SERINC3 and 5

Answer 30

TM proteins that aid in incorporating serine into lipids

Question 31

What does Nef prevent

Answer 31

Incorporating SERINC3/5 into virus, endosomal targetting

Question 32

What is the function of NONO (controversial)

Answer 32

Nuclear capsid sensor which detects when capsid enters nucleus.

Question 33

Why is NONO controversial?

Answer 33

We don’t know if capsid even enters the nucleus.