摘要 |
DNA constructs are provided employing intronically positioned expression, systems, where one of the genes is a dominant gene, usually amplifiable, and the other gene encodes a sequence of interest. Higher levels of co-expression are achieved than when the genese are ligated in tandem. Specifically, the gene of interest is inserted into the intron of a DHFR minigene, the construct transformed into a mammalian cell and the resulting transformants stressed with progressively increasing levels of methotrexate. Substantially increasing levels of co-expression are achieved with increasing levels of methotrexate.
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