Retrovirus

What are characteristics of Retroviruses?

• A.

  Can squire host genes

• B.

  Can insert into the germline of a host

• C.

  Can be used as a vector for foreign gene

• D.

  Source of reverse transcriptase

• E.

  All of the above

Retroviruses are primarily vertebrate viruses as well as insects and mollusks

• A.

  True

• B.

  False

Attachment with Retroviruses requires CD4 and a co-receptor called __________

How does Retrovirus attach/fuse with cells?

• A.

  Envelope protein is cleaved by cellular proteases

• B.

  SV stands for Surface Virus

• C.

  TM stands for Transmembrane Protein

• D.

  SV binds to CCr5 and CD4

• E.

  TM binds to CCR5

• F.

  Fusion peptide inserts into membrane

Reverse transcription produces double stranded DNA copy from an RNA genome

• A.

  True

• B.

  False

Uses 3' OH as primer for DNA synthesis

• A.

  True

• B.

  False

Uses tRNA on PB as a primer

• A.

  True

• B.

  False

After the primer binds to the PB on the 5' end, the 3' end of newly synthesized DNA gets extended starting at the U5 region and then....

• A.

  TRNA-DNA hybrid transfers to other end of template

• B.

  The R regions base pair

• C.

  All RNA gets degraded

After the 3' end is extended, all of the RNA template has been removed by RNAse H

• A.

  True

• B.

  False

PP is a piece of RNA that gets left behind and is used primer for reverse transcriptase.

• A.

  True

• B.

  False

The PB on each end base pair to one another and form a circular molecule, with the 3' end being extended by the reverse transcriptase until you are left with a final double stranded DNA molecule

• A.

  True

• B.

  False

Why is there extra sequence added on to each end (the LTR)?

• A.

  To serve as a promoter

• B.

  To ensure all genes inside that region gets transcribed

• C.

  To integrate into the host

What is used to cut host DNA and insert the dsDNA into the cut site?

What is the promoter for transcription?

Polymerase can bind to both U3 regions

• A.

  True

• B.

  False

One pre-mRNA can be made into:

• A.

  Translated directly: gag & pol

• B.

  Spliced: gag & pol + other proteins

• C.

  Spliced: gag & pol only

• D.

  Genomic RNA: packaged into virus particles

A ribosomal frameshift is needed for gag expression

• A.

  True

• B.

  False

The gag polyprotein contains:

• A.

  MA: matrix protein

• B.

  CA: capsid protein

• C.

  NC: nuclecapsid protein

• D.

  POL: polymerase

• E.

  IN: integrase

The pol polyprotein contains:

• A.

  MA: matrix protein

• B.

  CA: capsid protein

• C.

  NC: nuclecapsid protein

• D.

  POL: polymerase

• E.

  IN: integrase

• F.

  PRO: protease

How is the virus released?

• A.

  Budding through outer membrane

• B.

  Lyses the cell

• C.

  Creates a pore