Development of infectious recombinant BK virus

The polyomavirus, BK virus (BKV) infects the majority of humans early in life, establishing persistent asymptomatic infections in immunocompetent individuals. The small size and non-redundant nature of the viral genome presents a challenge in developing recombinant BKV (rBKV). A strategy is described for engineering rBKV by fusing sequences coding for foreign polypeptides via the self-processing 2A peptide in frame to the BKV agnoprotein or VP2 capsid protein genes. This novel approach aims to minimize alterations to native BKV polypeptide sequences and expression, potentially allowing maintenance of viral viability. To test this concept, a panel of rBKV was constructed that express either enhanced green fluorescent protein (EGFP), or different forms of the HIV-1 Gag polypeptide under control of the native BKV late transcriptional unit, and with appropriate self-processing. Although most of these rBKV proved to have stability issues, such approaches may have utility as reporter viruses or as gene delivery vectors.

► We describe a strategy for engineering rBKV.
► Foreign sequences are fused via the self-processing 2A peptide in frame to the agnoprotein or VP2 genes.
► Expression of inserted genes under control of the BKV late promoter.