30. Retroviruses 2

Question 1

why are retroviruses considered a genetic disease?

Answer 1

bc of provirus

Question 2

organization of Gag protein

Answer 2

1. MA
2. CA
3. NC
4. p6

Question 3

what is p6?

Answer 3

2 spacer peptides

Question 4

where does viral protease cleave on Gag?

Answer 4

cleaves between MA, CA, NC, and P6

Question 5

what part of matrix protein is required for membrane binding?

Answer 5

N-terminal myristyl group

Question 6

what 2 parts of nucleocapsid bind RNA?

Answer 6

highly basic N-terminus and Zn fingers

Question 7

binding of Gag to HIV RNA may promote:

Answer 7

binding of Gag to HIV RNA may promote Gag-Gag interaction

Question 8

3 additional roles of nucleocapsid protein besides binding RNA

Answer 8

1. unwinds tRNA primer and places it onto pbs
2. facilitates processive DNA synthesis
3. interacts with Vpr which is involved in pre-integration complex

Question 9

why is RNA in the core as a dimer?

Answer 9

allows replicative and survival advantage

Question 10

why does dimer of RNA allow survival advantage?

Answer 10

there’s an extra template when one gets damaged

Question 11

role of p6

Answer 11

binds host factors involved in membrane curvature for binding

Question 12

what happens if you mutate p6?

Answer 12

virus doesn’t bud off and gets stuck at the membrane

Question 13

what mediates membrane curvature by binding p6?

Answer 13

ESCRT mediates membrane curvature and binds p6

Question 14

3 requirements for infectious virus

Answer 14

1. correct order of cleavage
2. correct genome packaging (dimerization)
3. viral protein proportions

Question 15

3 models for retrovirus uncoating

Answer 15

1. uncoats in cytoplasm
2. uncoats at nuclear pore
3. uncoats inside nuclear pore

Question 16

which model for uncoating is correct?

Answer 16

unknown –> may be combo of all 3

Question 16

is all retrovirus RNA spliced?

Answer 16

no –> some is spliced, some is not

Question 16

which mRNAs are more spliced?

Answer 16

auxillary proteins