Homologous Recombination in the Replicative Cycle of Adenoviruses and Its Relationship to DNA Replication

The observation that adenovirus genomes can undergo genetic recombination is almost a quarter of a century old (Williams and Ustacelebi 1971; Takemori 1972; Ensinger and Ginsberg 1972), yet despite its early discovery and its rapid exploitation as a tool for mapping mutations and for creating new genotypes (reviewed in Ginsberg and Young 1977; Young et al. 1984b), the mechanisms underlying it are not well understood at the molecular and biochemical levels. Such an understanding, however, can be expected to shed light not only on the specific features peculiar to adenovirus recombination itself, but also on the more general characteristics of the repair and recombinational capacities of the cell. These cellular aspects are of considerable current theoretical and practical interest, because of recent advances both in uncovering the molecular basis of genetic defects in DNA repair in mammalian cells and in the techniques of gene targeting by homologous recombination in order to investigate mammalian development and differentiation. As with many other fundamental biological phenomena, the study of adenovirus recombination can be expected to yield valuable insights into the normal capacities of the cell.