Viral multiplication strategies

Viral multiplication strategies - reverse transcriptase...

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Viral multiplication strategies - Subsequent events - biosynthesis of viral components, maturation, and release - vary greatly among different groups of animal viruses (Tortora et al. Table 13.4) = For DNA viruses, the genome must migrate into the nucleus before the genes can be expressed (Tortora et al., Figure 13.15) = For RNA viruses, gene expression can occur in the cytoplasm (Tortora et al. Figure 13.17) · If the virion genome is plus strand RNA, it can serve directly as a messenger RNA and be translated into viral proteins by the host cell's ribosome · If the virion genome is minus strand RNA, it must be transcribed by a viral RNAdependend RNA polymerase (which must be brought in with the genome) = In one group of RNA viruses, the retroviruses (of which HIV-1 and HIV-2 are the best known), the nucleotide sequence of the viral genome is copied as DNA by a viral
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Unformatted text preview: reverse transcriptase (Tortora et al., Figure 13.19) The reverse-transcribed DNA is then integrated into a host chromosome as a provirus The provirus genes can then be transcribed to provide viral mRNAs and virion genomes Alternatively, the provirus can remain latent the way the a prophage does Sometimes, integration of the provirus can cause malignant transformation of the host cell = Different RNA viruses employ a variety of (often very complicated) multiplication strategies- In contrast to phage release, release of animal virus virions does not always kill the host cell (although the cell usually dies anyway due to damage accumulated during the multiplication cycle) = Many enveloped viruses are released by budding (Tortora et al., Figure 13.20) = Naked viruses are more likely to be released by lysis of the host cell...
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