Adeno-Associated Virus serotype 9 (AAV9) is one of the most promising serotypes for gene therapy applications. AAV9 transduces a wide range of tissue types, including cardiac and skeletal muscle, liver, pancreas, and eye tissue. AAV8 and AAV9 have recently been used to correct disease-causing mutations and improve muscle function in mouse models of Duchenne muscular dystrophy. AAV9 has significantly lower seroprevalence in the human population than other AAV serotypes, making AAV9 a desirable candidate for therapeutic applications.These AAV particles constitutively express the firefly (Photinus pyralis) luciferase and mCherry genes connected via a T2A linker, under the control of a CMV promoter. The T2A self-cleaving peptide (derived from Thosea asigna virus 2A) leads to the efficient cleavage of the transcript and expression of luciferase and mCherry as two separate proteins.