Full-length sequence analysis of subacute sclerosing panencephalitis (SSPE) virus, a mutant of measles virus, isolated from brain tissues of a patient shortly after onset of SSPE.
Subacute sclerosing panencephalitis (SSPE) virus, a measles virus (MeV) mutant, was isolated from brain tissues of a patient shortly after the clinical onset, and the entire viral genome was sequenced. The virus, named SSPE-Kobe-1, formed syncytia on B95a and Vero/SLAM cells without producing cell-free infectious virus particles, which is characteristic of SSPE virus. Phylogenetic analysis classified SSPE-Kobe-1 into genotype D3. When compared with an MeV field isolate of the same genotype (Ich-B strain), SSPE-Kobe-1 exhibited mutation rates of 0.8-1.6% at the nucleotide level in each of the proteincoding regions of the viral genome. It is noteworthy that the mutation rate of the M gene (1.2%) of SSPE-Kobe-1 was considerably lower than for other SSPE virus strains reported so far, but that the majority of the mutations (75%) were the uridine-to-cytidine biased hypermutation characteristic of the SSPE virus M gene. At the amino acid level, the viral proteins, such as N, P, C, V, M, F, H and L proteins, had point-mutations on 3, 7, 1, 4, 3, 9, 8 and 14 residues, respectively, compared with the Ich-B strain. In addition, the F and H proteins had mutated C-termini due to single-point mutations near or at the stop codons. Two of the three mutations in the M protein were Leu-to-Pro mutations, which are likely to affect the conformation and, therefore, the function of the protein. Because of the relatively small number of mutations, SSPE-Kobe-1 would be a useful tool to study genetic evolution of SSPE virus.
Hotta
Hak
H
Division of Microbiology, Kobe University Graduate School of Medicine, Kobe, Japan. hotta@kobe-u.ac.jp
Nihei
Kenji
K
Abe
Yu-ichi
Y
Kato
Seiichi
S
Jiang
Da-Peng
DP
Nagano-Fujii
Motoko
M
Sada
Kiyonao
K
D000595:Amino Acid Sequence; D001483:Base Sequence; D001921:Brain / Q000821:virology*; D002675:Child, Preschool; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D013190:SSPE Virus / Q000235:genetics*; D013344:Subacute Sclerosing Panencephalitis / Q000821:virology*