POXVIRUS

1. The 'Almost-Organism'
   1. The first virus seen (light microscope)
   2. Extremely complex
      1. Multi-layered
      2. Even contains what might be considered a glycocalyx
   3. Almost total parasites
   4. Extremely narrow host ranges
   5. Widely distributed among animals (entomopox, mousepox, rabbitpox, smallpoxŠ)

2. 'Life Cycle'
   1. Gross Anatomy
      1. Ovoid shape (400x240x200 nm); 4x10⁹ dal (5000 S)
      2. dsDNA: 1.22x10⁸ dal (185 kbp = 150-200 genes [approx. 1/40 of E. coli genome]); single covalently linked circle (unique to virions)
      3. DNA-polymerase has many sequence homologies to those of Herpes and AV
      4. "Burst size" = 10,000 (actually leak out); Latent period = about 15 hrs.
      5. Joklik is one of the main researchers (Duke)
      6. Core contains a number of enzymes ready to work
         1. Poly(A)polymerase
         2. mRNA guanylyltransferase
         3. mRNA (guanine-7-)methyltransferase
         4. mRNA (ribose-2'-)methyltransferase
         5. RNA-dependent nucleoside triphosphatases
         6. DNases
         7. Protein kinase (phosphorylates serine and threonine)
         8. anti-nickase (ligase)
   2. Replication Cycle
      1. Autonomous (besides all dsDNA viruses kill eukaryotic cells)
         1. Everything takes place in the cytoplasm
         2. Proof of autonomy in enucleated cells produced by cytochalasin treatment
      2. Face life in a way that RNA viruses do as they do not make use of host nuclear enzymes
      3. Of the progeny components, DNA synthesis occurs first
         1. Early genes of DNase-resistant, partially packaged, parent DNA are transcribed
         2. Early functions are thymidine kinase, DNA polymerase, ligase and DNase.
      4. Late components are products of the progeny DNA's
         1. Genomes are uncoated
         2. Somehow there is blockage of translation of early enzymes.

3. Engineering Tool
   1. Vaccinia: a vector of genes
   2. AIDS genes

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