Retroviruses (Dr. Yoshimura)

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Retroviruses (Dr. Yoshimura)
2012-09-05 12:12:19

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  1. Which 2 human retroviruses cause immunodeficiency?
    • HIV I
    • HIV II
  2. Which 2 human retroviruses cause cancer and how are they usually transmistted?
    • HTLV I
    • HTLV II
    • Transmissted via sex, breastfeeding and contaminated blood
  3. What is the flow of genetic information in a retrovirus?
    RNA > DNA > RNA
  4. What is genome of a retrovirus?
  5. Match the following.

    1. Alpharetroviruses
    2. Betaretrovirus
    3. Deltaretrovirus
    4. Gammaretrovirus
    5. Epsilonretrovirus
    6. Lentivirus
    7. Spumavirus

    A. Chimpanzee foamy virus
    B. HTLV I and II
    C. HIV
    D. Walleye dermal sarcoma virus
    E. Avian leukosis
    F. Feline leukema virus
    G. Mouse mammary tumor virus
    • 1. E
    • 2. G
    • 3. B
    • 4. F
    • 5. D
    • 6. C
    • 7. A
  6. Retrovirus virion morphology
    Shape? Envelop/Non-envelope? Capsid shape? Viral proteins?
    • Shape?
    • Spherical
    • Envelop/Non-envelope?
    • Yes
    • Capsid shape?
    • Icosahedral
    • Viral proteins?
    • SU
    • TM
    • MA
    • CA
    • NC
    • RT
    • PR
    • IN
  7. True or False. Retrovirus have a both a simple and complex RNA genome.
  8. Describe the simple RNA genome of retroviruses.
    Contains gag (CA, NC, MA), pol (PR, RT, IN) and env (SU, TM) genes
  9. Describe the complex RNA genome of retroviruses.
    Contains gag (CA, NC, MA), pol (PR, RT, IN) and env (SU, TM) genes, in addition to vif, tat, vpr, vpu, rev and nef genes.
  10. What is the replication cycle of retroviruses?
    virus binds to CD4 receptor and co-receptor on CD4+ T cell > fuses then penetrates and invades cell > viral RNA is transcripted via reverse transcriptase > dsDNA is produced > ligation > integration into host DNA > transcription of host DNA with viral genes > ssRNA (viral mRNA + progeny RNA) > translation of viral proteins > assembly of nucleocapsid > budding and release
  11. What are the 3 types of retroviral RNA that are transcribed upon infection of the host?
    • Unspliced RNA - viral genome, structural proteins
    • Single-spliced mRNA - Env polyprotein
    • Multiple-spliced mRNA - regulatory proteins, accessory proteins
  12. True of false. Retroviral transformation is defined as unstable, heritable change in the growth control of cells.
    False, Retroviral transformation is defined as stable, heritable change in the growth control of cells.
  13. What are the 2 major mechanisms of retroviral transformation?
    • Transduction of an oncogene
    • Insertional mutagenesis - provirus integration that is adjacent to a cellular proto-oncogene