Virus and genes

Hota-Mitchell, S., Clarke, M.W., Podesta, R.B. and Dekaban, C.A. (1 999) Recombinant vaccinia viruses and gene gun vectors expressing the large subunit of Schistosoma mansoni calpain used in a murine immunization-challenge model. Vaccine 1 7, 1 338-1354. 

Answers to many basic problems of biology—nature of growth, mechanism of duplication of viruses and genes, action of enzymes, mechanism of physiological activity of drags, hormones, and vitamins, structure and action of nerve and brain tissue— may lie in knowledge of molecular structure and intermolecvlar reactions. 

Viruses and Genes. Viruses exhibit the three fundamental properties of genes In host cells they replicate identically, i.e., the virus multiplies they express some characteristic—in this case the symptom of a disease and they may undergo mutation. Mutants differ, among other things, in the symptoms that they cause and in the constitution of viral protein. Mutants have also been developed artificially (e.g., with nitrous acid cf. Section 4). 

Pauling (65) expresses the foregoing conclusion in other words. He says that a specific type of molecular structure may be the basis of growth, the mechanism of reproduction of viruses and genes, the action of enzymes, the mechanism of the physiological activity of drugs, hormones, and vitamins, and the structure and action of nerve and brain tissue. To these activities of tissues determined by molecular structure, we may add muscular action (55,75), protoplasmic streaming (51,82), and certain metabolic activities of the cell (71) and the body as a whole (75). 

Palese, P, and Roizman, B., 1996. Genetic engineering of viruses and of virus vectors A preface. Proceedings of the National Academy of Sciences U.S.A. 93 11287-11425. A preface to a. series of papers from a colloquium on genetic engineering and mediods in gene dierapy. 

Figure 36-11. The integration of a circuiar genome from a virus (with genes A, B, and C) into the DNA moie-cuie of a host (with genes 1 and 2) and the consequent ordering of the genes.

Kieffer TL, Finucane MM, Nettles RE, Quinn TC, Broman KW, Ray SC, Persaud D, SUiciano RF (2004) Genotypic analysis of HIV-1 drug resistance at the limit of detection virus production without evolution in treated adults with undetectable HIV loads. J Infect Dis 189(8) 1452-1465 Kinoshita S, Su L, Amano M, Timmerman LA, Kaneshima H, Nolan GP (1997) The T cell activation factor NF-ATc positively regulates HIV-1 replication and gene expression in T cells. Immunity 6(3) 235-244... 

The genes of the inducible and the constitutively expressed forms of NOS have been cloned and expressed. The expression of inducible NOS in the brain tissue of animals with experimentally induced neurological disorders (boma disease virus and rabies virus in rats), herpes simplex virus (mice) and experimental allergic encephalitis (in rats) suggests that NO produced by induced NOS may be a toxic fector in the pathogenesis of neurological diseases (Koprowski et /., 1993). 

Wang, J., and Baltimore, D. (1983). Cellular RNA homologous to the Abelson murine leukemia virus transforming gene expression and relationship to the viral sequence. Mol. Cell. Biol. 3 773-779. 

Chalifour, L. E., Wirak, D. O., Hansen, U., Wassarman, P. M., and DePamphilis, M. L. (1987). Cis- and trans-acting sequences required for expression of simian virus 40 genes in mouse oocytes. Genes Dev. 1 1096-1106. 

Several enveloped viruses, and some physical gene transfer techniques such as electroporation, deliver the nucleic acid into the cell by direct crossing of the cell membrane. Lipid-based, enveloped systems can do this by a physiological, selfsealing membrane fusion process, avoiding physical damage of the cell membrane. For cationic lipid-mediated delivery of siRNA, most material is taken up by endo-cytotic processes. Recently, direct transfer into the cytosol has been demonstrated to be the bioactive delivery principle for certain siRNA lipid formulations [151]. 

Lee, J.H., Baker, T.J., Mahal, L.K., Zabner, J., Bertozzi, C.R., Wiemer, D.F., and Welsh, M.J. (1999) Engineering novel cell surface receptors for virus-mediated gene transfer./. Biol. Chem. 274, 21878. 

A number of additional viral types may also prove useful as vectors in the practice of gene therapy. Chief amongst these are the adenoviruses. Adeno-associated virus, the herpes virus, and a number of other viruses, are also being considered (Table 14.2). 

Additional viruses that may prove of some use as future viral vectors include adeno-associated virus and herpes virus. Adeno-associated virus is a very small, single-stranded DNA virus its genome consists of only two genes. It does not have the ability to replicate autonomously and can do so only in the presence of a co-infecting adenovirus (or other selected viruses). 

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