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Viral Genetics

Viral Genetics. Hsiao-Sheng Liu 劉校生 國立成功大學微生物暨免疫學研究所. The objectives. What kind of genetic changes are detected in viruses? The effects of viral genetic changes on viral virulence The application of viral mutants. What kind of genetic changes are detected in the virus?. A. Mutation

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Viral Genetics

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  1. Viral Genetics Hsiao-Sheng Liu劉校生國立成功大學微生物暨免疫學研究所

  2. The objectives • What kind of genetic changes are detected in viruses? • The effects of viral genetic changes on viral virulence • The application of viral mutants

  3. What kind of genetic changes are detected in the virus?

  4. A.Mutation Poor fidelity of viral polymerase: RNA-dependent RNA polymerase; RNA virus lack of genetic error-checking mechanism (one error per 1x10 nucleotides) Rapid replication rate 3

  5. A.Mutation B. Recombination (Reassortment)

  6. HA NA HA NA Attenuated virus Violent virus Hemagglutinin HA NA Neuraminidase Lipid bilayer Ribonucleoprotein Matrix protein Recombinant virus

  7. Antigen drift: gene mutation • Antigen shift: gene recombination

  8. Antigen Antigen

  9. NP: nucleoprotein Mutation Recombination

  10. Mutation Recombination (Reassortment) C. Transcapsidation: Phenotype of A and genome of B D. Marker rescue

  11. An example of viral genetic changes: SARS

  12. Molecular analyses by RT-PCR: @ A 405 nucleotide segment of the coronavirus polymerase gene was amplified.

  13. From Times

  14. What kind of viral mutants may be generated?

  15. Mutants • Lethal mutant • Plaque mutant • Host-range mutant • Attenuated mutant • Temperature sensitive mutant

  16. What is the application of viral mutants? Vaccine Understanding a mutated virus is the first step to find a vaccine

  17. Why the virus is used for gene therapy?

  18. 1. Rapidly amplified in appropriate cell 2. Deliver the gene without producing infectious virus

  19. What viruses are used for gene therapy?

  20. Virus-mediated gene transfer in mammalian cells 1. Retrovirus 2. Adenovirus 3. Adenovirus-associated virus 4. Herpes simplex virus

  21. What is the defective virus?

  22. A. Defective Interfering viral particle (DI) B. Pseudovirion: Virus particle contains host nucleic acid

  23. Web site for virology • General virology: www.tulane.edu/~dmsander/garryfavweb.html • Taxonomy of viruses: life.anu.edu.au/viruses/Ictv/index.html • Infectious diseases: www.gen.emory.edu/medweb/medweb.id.html

  24. Genetic change between viral particles

  25. H1N1 H5N1

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