AAV5-CMV-mCherry

The use of adeno-associated viruses (AAVs) in gene therapy has led to efforts to identify low-prevalence serotypes that are able to evade existing immunity. Unlike other common serotypes that have been identified as culture contaminants, AAV serotype 5 (AAV-5) was originally isolated from human lesions. The increasing number of identified serotypes allows the construction of an AAV phylogenetic tree, which may reveal some candidate viruses that are worthy of further study. AAV-5 is highly variable compared to all other serotypes and is more distantly related to other parvoviruses. Serological studies have shown that 30% to 60% of the human population is seropositive for AAV-5. Therefore, this prevalent and highly variable AAV may have special properties that are worthy of study.

The genome structure of AAV-5 is similar to other serotypes. The single-stranded viral genome is connected at both ends by inverted terminal repeats (ITRs) and contains two major genes, Rep and Cap, which encode replication and capsid proteins, respectively. However, studies on specific biological properties of AAV-5 have elucidated its properties that are different from other AAVs. For example, AAV-5 has differences in transcription and RNA processing, involving alternative polyadenylation and distance-dependent RNA processing. Several unique transcripts are produced in the AAV-5 genome, such as functional truncated versions of viral replication proteins. In addition, in contrast to other serotypes, transcription of the AAV-5 capsid protein does not require Rep expression. Thus, both the genomic sequence and potential biological properties of AAV-5 are highly diverse.