Electron tomography of HEK293T cells using scanning electron microscope-based scanning transmission electron microscopy

Subcellular distribution of the rAAV genome depends on genome structure

Many studies have been conducted on the transduction efficiency of recombinant adeno-associated virus (rAAV) depending on the serotype and genome structure, such as single-stranded (ss) and self-complementary (sc). To understand the variation in therapeutic efficacy, we focused on investigating subcellular distribution of viral genome depending on rAAV genome structure. It is critical to ascertain the location of the virus within the host cell after the entry because a larger amount of the viral genome placed in the nucleus facilitates viral genome replication by utilizing the host cell's system, thereby enhancing the therapeutic outcome. In this sense, tracking the location of the virus within the host cell's organelles can inform a new strategy to improve therapeutic efficacy. Therefore, we attempted to stain only the viral genome with APEX2 and DAB chemicals specifically, and the distribution of the viral genome was examined by transmission electron microscopy (TEM). Consequently, when the two types of rAAV were transduced for 6 h, scAAV2 tended to be more located in the lysosome and nucleus compared to ssAAV2.