NUCLEIC ACID CONSTRUCTS FOR SIMULTANEOUS GENE ACTIVATION

Herein are reported novel DNA constructs and methods using the same. The current invention uses a deliberate arrangement of non-productive/inactive promoters and genes on coding and template strands of DNA molecules, which are converted into their active form by the interaction with a site-specific recombinase. In more detail, the DNA element according to the current invention is non-functional with respect to the expression of the contained first and second genes. By being non-functional with respect to the expression of the first and second gene, the DNA element according to the invention can be integrated into genome of a cell without the risk that the comprised structural genes are expressed already directly after the integration. The genes are only expressed once a recombinase recognizing and functional with the recombination recognition sequences of the DNA element is activated or introduced into the cell. Thereby, a recombinase mediated cassette inversion (RMCI) between the first and second mutated recombinase recognition sequences in the genomically integrated DNA element of the invention is initiated. The RMCI results in an inversion of that part of the DNA element according to the invention that is located between the two mutant recombinase recognition sequences. Thereby the first promoter becomes operably linked to the first gene and the second promoter becomes operably linked to the second gene. Only thereafter, the first and second genes are transcribed and the respective encoded proteins are expressed. Thus, the DNA element according to the current invention is especially useful in the simultaneous activation of two genes within a cell.