Dynamic activation of rAAV transgene expression by a small molecule that recruits endogenous transcriptional machinery

The silencing of adeno-associated virus (AAV) vectors over time poses a challenge to the development of effective gene therapies. Here, we describe a bioorthogonal platform for tuning AAV expression, enabling the controlled activation of viral transgenes after transduction. This platform uses a small, synthetic DNA binding protein embedded in the AAV genome coupled with a heterobifunctional small molecule that recruits endogenous transcriptional machinery to chemically induce transgene expression in a dose-dependent and reversible manner. In human cells, this strategy successfully activates AAV expression across different viral serotypes, cassette configurations, and transgene payloads. Epigenomic analysis reveals that this technology facilitates direct and specific recruitment of the transcriptional regulator BRD4 to AAV genomes. Our results demonstrate that the expression of native AAV genomes can be tuned through chemically induced proximity (CIP), opening the possibility of a new class of AAV vectors that can be dynamically potentiated. Overall design: CUT&RUN in AAV-infected U2OS cells for BRD4, H3K27ac, and H3K9ac with and without treatment of C207.