Figure 1: Schematic representation of the JCV genome organization. The circular, double-stranded DNA genome is ~5.2 kb in size and is divided into the early coding region and the late coding region, transcribed in opposite directions from a common noncoding control region (NCCR). Early genes include large T antigen (T-Ag), small t antigen (t-Ag), T′135, T′136, and T′165. Late genes include VP1, VP2, VP3, and agnoprotein.