Abstract |
A very flexible and tightly regulatable expression system has been constructed. It uses the principle of invertible promoters [Podhajska et al., Gene 40 (1985) 163-168]. Here, we describe the construction of a plasmid that provides the integrase, which causes promoter inversion in a tightly regulated fashion, as well as modified plasmids carrying the invertible module. The way the integrase is provided on a separate plasmid closely mimicks expression of the integrase from a lambda lysogen. Thus, the flexibility of the original system is considerably extended by making it strain-independent without compromising the tight regulation. We present the expression of a single-chain T-cell receptor fragment as an example of application, in order to illustrate the properties of this expression system.
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