A simple technique for the rescue of early region I mutations into infectious human adenovirus type 5

WJ McGrory, DS Bautista, FL Graham - Virology, 1988 - Elsevier
WJ McGrory, DS Bautista, FL Graham
Virology, 1988Elsevier
Abstract Early region 1 (E1) of the human adenoviruses has many intriguing properties
which have prompted numerous mutational studies to help delineate and characterize the
domains responsible for these functions. In mutational analyses being done currently, the El
region is usually cloned into a bacterial plasmid where it is mutated and then the altered El
sequences are “rescued” back into infectious virus. The most frequently used rescue
procedures are somewhat tedious, requiring the purification and fractionation of linear viral …
Abstract
Early region 1 (E1) of the human adenoviruses has many intriguing properties which have prompted numerous mutational studies to help delineate and characterize the domains responsible for these functions. In mutational analyses being done currently, the El region is usually cloned into a bacterial plasmid where it is mutated and then the altered El sequences are “rescued” back into infectious virus. The most frequently used rescue procedures are somewhat tedious, requiring the purification and fractionation of linear viral DNA or DNA fragments, and often involve the screening of numerous plaque isolates. Several observations we have made recently on the properties of adenovirus DNA in infected cells and on infectious plasmids in transfected cells led us to design a new approach for rescuing E1 mutations into infectious viral genomes. We constructed a plasmid, pJM17, containing the entire Ad5 DNA molecule, with an insert in the El region that exceeds the packaging constraints of the adenovirus capsid. Following transfection of pJM17 into 293 cells the plasmid DNA is able to replicate but cannot be packaged into infectious virions. In contrast cotransfection of 293 cells with pJM17 plus an E1-containing plasmid carrying mutated sequences produces recombinant virions at high efficiencies. Neither plasmid needs to be linearized prior to cotransfection. The technique eliminates the need to purify and manipulate infectious virion DNA and since no unique restriction sites are needed, both ElA and E1 B mutants as well as foreign gene inserts in the E1 region can be easily rescued into virus.
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