1. Comparison of infectious JC virus DNAs cloned from human brain
B W Grinnell, B L Padgett, D L Walker J Virol. 1983 Jan;45(1):299-308. doi: 10.1128/JVI.45.1.299-308.1983.
We cloned JC virus DNA obtained directly from brain tissue of 10 cases of progressive multifocal leukoencephalopathy and compared DNAs by restriction endonuclease mapping. Before cloning, each DNA preparation was homogeneous with respect to restriction patterns, but with the cloned DNAs we found variability in three regions of the genome among DNAs from different cases. There was a region of hypervariability between 0.67 and 0.725 map units; no two DNAs were exactly alike in this region. We determined that the origin of DNA replication also was in this region at 0.69 +/- 0.02 map units. In 4 of the 10 DNAs examined there was a deletion of approximately 75 base pairs between 0.14 and 0.235 map units, the region presumed to contain the codons for the C-terminal ends of the structural protein Vpl and for T antigen. JC virus DNA from these same four cases had an additional HincII-HpaI site at 0.895 map units in the presumptive Vp3 and Vp2 coding regions. Overall, no two JC virus genomes were identical although all were from fatal central nervous system infections and were infectious in vitro. Our restriction patterns suggest that there are two subtypes of JC virus circulating in the population.
2. Analysis of JC virus DNA purified directly from human progressive multifocal leukoencephalopathy brains
F Rentier-Delrue, A Lubiniecki, P M Howley J Virol. 1981 May;38(2):761-9. doi: 10.1128/JVI.38.2.761-769.1981.
Human polyomavirus JC DNA was purified directly from the diseased brain tissue of two patients with progressive multifocal leukoencephalopathy (PML) by a method employing differential salt precipitation (B. Hirt, J. Mol. Biol. 26:365-369, 1967). Each of the viral genomes (JC-NIH-1 and JC-NIH-2) was molecularly cloned intact in Escherichia coli, using pBR322, at their unique EcoRI (0.00 map unit) and BamHI (0.51 map unit) sites. The JC-NIH-1 genome was approximately 50 base pairs larger and the JC-NIH-2 genome was approximately 50 base pairs smaller than the prototype human polyomavirus JC (Mad-1) DNA. Analysis of the restriction endonuclease cleavage fragments of these two DNAs and the human polyomavirus JC (Mad-1) DNA revealed only slight differences which mapped in a region of the genome extending from 0.67 to 0.74 map unit. From previous homology studies, this region of variance corresponds to the noncoding region to the late side of the origin of DNA replication.
3. Naturally occurring and passage-induced variation in the genome of JC virus
B W Grinnell, J D Martin, B L Padgett, D L Walker Prog Clin Biol Res. 1983;105:61-77.
We have examined both the naturally occurring and passage-induced variation in the genome of the human polyomavirus, JCV. JCV DNA was extracted directly from diseased brain tissue of ten cases of progressive multifocal leukoencephalopathy (PML) and the DNA population from any one case was homogeneous with respect to length and restriction endonuclease cleavage patterns. However, a comparison of cloned JCV DNAs revealed that the viral DNAs derived from different cases of PML were not identical. We identified a hypervariable region near the origin of DNA replication, and we demonstrated that there are two genetically distinguishable subtypes of the virus. After growth in vitro, the DNA from certain isolates of JCV became heterogeneous in size. Deletions of up to 12% of the genome occurred after as few a three low multiplicity passages in human glial cells. Most of the deletions mapped within the region presumed to code for T antigen. In addition, we examined the physical properties of JCV from brain and, as expected, they were typical of the polyomavirus genus.
