This vector uses a bidirectional U6 promoter to express 2 small hairpin RNA sequences that can silence the expression of 2 genes simultaneously. Two short cDNAs that include sequences from the target genes are ligated into insertion sites at each end of the promoter.?The cDNAs are constructed by annealing compementary oligonucleotides to one another.?Each oligonucleotide is designed with a 4-base overhang at its 5'-end.?The overhangs complement vector sequences that remain after digestion with a pair of restriction enzymes that are unique to each insertion site.?The other features of the plasmid facilitate rapid conversion to an adenovirus vector using the SpeAd procedure.

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