| 摘要 |
A method for potentiating a host cell for sensitivity to a heterologous polynucleotide comprises providing a population of host cells, wherein the cells comprise a heterologous polynucleotide, a first promoter regulating the expression of the heterologous polynucleotide, and a replicable genetic element comprising a second polynucleotide encoding a repressor of the first promoter, a reporter gene under the control of a second promoter, expression of which provides a detectable label, and an origin of replication, wherein the replicable genetic element is subject to loss by the host cells, thus resulting in heterogeneously labeled colonies when the host cells are cultured; mutagenizing the population of host cells; growing colonies of the mutagenized host cells under conditions wherein the heterologous polynucleotide, the repressor, and the reporter are all expressed; and identifying a colony of mutagenized host cells that is homogeneously labeled.
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