Generation of recombinant adenovirus using the Escherichia coli BJ5183 recombination system

One of the most time-consuming steps in the generation of adenoviral vectors is the construction of recombinant plasmids. This chapter describes a detailed method for the rapid construction of adenoviral vectors. The method described here uses homologous recombination machinery of Escherichia coli BJ5183 to construct plasmids used in generation of adenoviral vectors. With this method, no ligation steps are involved in generating the plasmids, and any region of the adenoviral genome can be easily modified. Briefly, the full-length adenoviral genome flanked by unique restriction enzyme sites is first cloned into a bacterial plasmid. Next, the region of the viral genome to be modified is subcloned into a bacterial shuttle plasmid, and the desired changes are introduced by molecular biology techniques. The modified viral DNA fragment is gel-purified and cotransformed with the full-length plasmid, linearized in the targeted region, into BJ5183 cells. Homologous recombination in E. coli generates plasmids containing the modified adenoviral genome. Recombinant virus is generated following release of the viral DNA sequences from the plasmid backbone and transfection into a producer cell line. With this method, homogeneous recombinant adenoviruses can be obtained without plaque purification.