General Lab Information

Technologies Available for License

2014-019: Improved T7 Cloning and Expression Vectors

Invention: 2014-019

Patent Status: U.S. Patent Number 11,618,899 was issued on April 4, 2023

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Transcription of cloned genes by T7 RNA polymerase and translation of the mRNA directed by the highly efficient upstream sequence of the T7 major capsid protein (tg10), has been highly successful in producing a wide range of proteins in E. coli. However, T7 RNA polymerase is so active and tg10 so efficient that basal expression in the uninduced cell can produce enough target protein to prevent establishment of an inducible expression strain if the target protein is sufficiently toxic to the host cell. Several improvements have reduced basal levels of target protein in uninduced cells, thereby stabilizing expression strains and allowing a wider range of proteins to be produced. Despite these improvements, even in these better vectors or expression strains, some target proteins are toxic enough that inducible strains for producing them are unstable and can be maintained only with special care or are so toxic that inducible expression strains cannot be established at all. Therefore there is a need to develop simple better T7 expression systems that prevents basal expression of the target protein completely. The technology describes T7 expression vectors that completely prevent basal expression of the target proteins.


Describes vectors that can be used to reduce basal expression to levels where even strains for expressing proteins highly stressful to the host cell can be maintained and induced. In addition, using asymmetric ligation these vectors can be used to simultaneously clone two or three coding sequences for co-expression of the cloned proteins.


These vectors not only prevent basal expression of the target protein completely but also allow one to co-express two or three target proteins.

Applications and Industries

These vectors can be used to express toxic proteins either by themselves or co-expressed with other proteins.

Journal Publication & Intellectual Property