HBoV1 transcription map. HBoV1 transcription map. The ssDNA genome of HBoV1 is shown in negative polarity. The transcription and posttranscriptional units are depicted to scale, including the P5 promoter, 5′ splice donor sites (D1, D1′, D2, and D3), 3′ splice acceptor sites (A1, A1′, A2, and A3), the internal proximal polyadenylation site [(pA)p], and the distal polyadenylation site [(pA)d], which are functional when the ssDNA genome is converted to a dsDNA form. The left- and right-end hairpin structures of the genome (LEH and REH, respectively) are diagrammed. Six groups of HBoV1 mRNA transcripts detected during infection, which have either a long form of mRNA (RxL) that reads through the (pA)p site or a short form of mRNA (RxS) that is polyadenylated at the (pA)p site, are shown below the diagrammed genome. R1 mRNA has a minor species (R1m) that is unspliced at the central small intron (D3-A3). Major ORFs are depicted as colored boxes with the nucleotide and amino acid of the start codon and the stop codon indicated. Proteins expressed from each mRNA species are indicated beside their respective mRNAs with molecular masses in kilodaltons detected during infection. Jianming Qiu et al. Clin. Microbiol. Rev. 2017; doi:10.1128/CMR.00040-16