This AAV is a fLuc construct driven by the 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.

Firefly luciferase (fLuc) is an oxidative enzyme used in bioluminescence and is distinct from a photoprotein. In the luciferase reaction, light is emitted when luciferase acts on the appropriate luciferin substrate. Photon emission can be detected by a light-sensitive apparatus such as a luminometer or modified optical microscope. Firefly luciferase is commonly used as a reporter to assess the transcriptional activity in cells.