RECOMBINANT ADENOVIRUS-MEDIATED EXPRESSION IN NERVOUS SYSTEM OF GENES CODING FOR ION CHANNELS AND OTHER MOLECULES INVOLVED IN SYNAPTIC FUNCTION

Publisher Summary Recombinant (and thus nonreplicating) adenovirus is at present the gene transfer vector of choice for introducing genes of interest into postmitotic neurons in vitro, in slice cultures, and in vivo. The per-cell efficiency can be close to 100%. By controlling the multiplicity of infection and by choice of a suitable promoter, the level of expression can be controlled. Expression can persist for weeks under favorable conditions. Cytotoxic effects are sometimes a problem, but usually are not severe. Adenovirions enter the cells by a complex pathway, usually by initial attachment to an integrin, followed by endocytosis into endosomes. The viral DNA is transported to the nucleus where it exists as a linear molecule of approximately 36-40 kb, with a covalently attached protein at each end. This protein presumably contributes to nuclease resistance of the DNA and thus to the persistence of expression. In proliferating cells, the DNA is diluted during cell division. Transgenic mice, either deleted in (i.e., “knockouts”) or overexpressing a gene of interest, are an attractive tool for studying effects of genes in neurobiology. The recombinant adenovirus system can be established in a somewhat shorter period of time than can a transgenic mouse. If an introduced gene has a lethal embryonic phenotype, the adenovirus system is much more convenient for studying the adult phenotype. On the other hand, the volume of tissue in vivo that can be infected with adenovirus is limited by the number of injections and volume per injection that an animal will tolerate, because the virus does not spread appreciably through the extracellular space. Therefore, for a nonsecreted molecule such as a receptor or an ion channel, the broad region of expression achieved with transgenic mice cannot be duplicated by adenovirus.