AAV with CAG promoter driven Cre Inducible Venus

This AAV expresses DIO-Venus driven by an ubiquitous CAG promoter.

The roughly 1.8Kb CAG promoter (also known as CBA promoter or CAGGS promoter) is a strong synthetic promoter frequently used to drive high levels of gene expression in mammalian cells. The CAG promoter is composed of the following regulatory elements: (C) cytomegalovirus (CMV) early enhancer element; (A) the promoter region, the first exon, and the first intron of chicken beta-Actin gene, and (G) the splice acceptor of the rabbit beta-Globin gene. Like the EF1a promoter, the CAG promoter is commonly used as an alternative for the CMV promoter, from which the expression is decreased due to methylation/silencing. In many cell types tested, the CAG and EF1a promoters give much higher levels of expression than other commonly used cellular promoters such as the UBC and PGK promoters.

In the DIO scenario, the transgene of interest is inserted in reverse orientation relative to the 5' promoter and is flanked by oppositely oriented loxP and lox2272 sites. In the absence of Cre expression, the transgene will not be produced. In the presence of Cre expression, the transgene will be "FLip-EXchanged" or FLEXed, leading to expression of the transgene. This is due to a permanent Cre-mediated recombination/inversion of the flanked transgene. This arrangement is called DIO (double-floxed inverse ORF), Cre-ON, Flex-rev (reverse), Flex-ON/FlexON, or DIO-AAV/AAV-DIO (double-floxed inverse ORF in AAV).