Screening for Highly Active Plasmid Promoters via Fusion to /?-Galactosidase Gene
نویسندگان
چکیده
A plasmid containing promoter-deleted inactive /?-galactosidase gene [1] was used to select promoters of the pEP121 plasmid [2]. Colonies of cells harboring reactivated /?-galactosidase gene were identified by their red color on McConkey plates. The quantitative amounts of /?-galactosidase produced in each clone were estimated by assaying enzyme activity and by measuring the specific /?-galactosidase protein following fractionation of total cells’ proteins on polyacrylamide gel. A wide range of enzyme activities was observed. The most active promoter isolated was shown to promote /?-galactosidase production more efficiently, compared with the original /?-galactosidase promoter, amounting to 20% of all cell proteins. Such highly active promoters may be utilized in the future, to promote expression of cloned genes in bacteria.
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