JC VIRUS REGULATORY REGION REARRANGEMENTS AND GENOTYPES IN PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATHY - 2 INDEPENDENT ASPECTS OF VIRUS VARIATION

JC virus (JCV) causes the central demyelinating disease progressive mu ltifocal leukoencephalopathy (PML), JCV strains excreted in the urine are distinguishable from those in PML tissue by the configuration of t heir regulatory region to the right of ori: the archetypal regulatory region, 267 nucleotides long, is rearranged in PML tissue by deletion and duplication, Within the coding region JCV shows variations as a re sult of virus evolution. Four major genotypes are distinguishable of w hich Type 1 is based in Europe and Type 2 in Asia. Here, the regulator y region rearrangements and the viral genotypes of 29 JCV strains from PML brain were determined. Rearrangement patterns and genotypes were not associated, In general, deletions occurred before duplications, bu t exceptions to this rule exist. Each configuration of the 29 rearrang ed regulatory regions was unique and could be derived directly from th e non-rearranged, archetypal form.