Five complete genomes of JC virus type 3 from Africans and African Americans.

The central demyelinating disease progressive multifocal leukoencephalopathy (PML) is caused by the human polyomavirus JC virus (JCV). JCV evolved as geographically based genotypes of which Type 3 is an African variant first characterized in HIV-1 positive patients from Tanzania. This study reports the complete sequence of five JCV Type 3 strains. The entire JCV genome was PCR amplified from urine specimens of three African and two African-American individuals. The African consensus sequence was compared to the Type 1 and Type 2 prototype strains, JCV (Mad-1) and JCV(GS/B), respectively. Type 3 differed in 2.2% of its coding region genome from JCV (Mad-1) and in 1.3% from JCV(GS/B). Within the coding region the sequence variation among the three types was higher in the capsid protein VP1 and in the regulatory protein large T antigen than in the agnoprotein or in VP2/3. Notable Type 3-specific changes were located at sites adjacent to the zinc finger motif and near the major donor and acceptor splice junctions of large T antigen. Four of the five urinary Type 3 strains had an unrearranged, archetypal regulatory region. African strain #309 showed a 10-bp deletion at a location similar to that previously described for #307 from Tanzania. The African-American Type 3 strain #312 was closely related to the African consensus sequence. The complete genome of a urinary JCV strain from another African-American male, previously reported as a possible Type 5, showed a sequence difference of only 0.52% from the Tanzanian consensus and has been reclassified as a subtype of Type 3.