AAV with ALB(1.9) promoter driven Cre Inducible EGFP

This AAV expresses DIO-EGFP driven by a liver ALB(1.9) promoter.

The ALB(1.9) is a synthetic promoter of ~1.9 Kb. It is based on the human Albumin promoter as well as several other regulatory elements. This synthetic promoter gives an extremely high level of long-term, liver-specific transgene expression that is 100-100 fold greater than that of the CMV promoter. For short-term (1-2 weeks post-injection into mouse liver), ALB(1.9) gives comparable expression relative to that of the CMV promoter. However, the expression level of the CMV promoter decreases 100-1000 fold from its peak level within 10-20 weeks of DNA administration whereas the ALB(1.9) promoter sustains its initial high level of expression for over 1 year. Compared to the regular ALB promoter, which is also commonly used for liver-specific transgene expression, the expression level from ALB(1.9) is about 10-100 fold greater.

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).