Figure 2.

The life cycle of HBoV-1 infection. Diagrams of the cilia and junction molecules are used to represent a ciliated airway epithelial cell. The entry of HBoV-1 into cells is mediated by receptor-mediated endocytosis, followed by intracellular trafficking, and binding to an unidentified viral receptor that is expressed on both apical (ciliated) and basal cells, as illustrated (Steps 1–3). Invasion of the nucleus by the virus after it escapes from the late endosome (Step 4). The viral genome’s uncoated ssDNA is transformed into replicative form dsDNA in the nucleus, where it produces viral NS proteins and BocaSR (Steps 5–8). The viral DNA then continues to replicate in the nucleus (Steps 12–16), produces viral NS and capsid proteins (Steps 9–11), and packages its genome into an empty capsid (Steps 12–16). (Steps 16–18). Eventually, the virus developed. Based on HBoV-1 research and references from other parvoviruses, which are described in the text, the HBoV-1 infection cycle in the ciliated epithelial cell is depicted.