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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
Author(s) -
Hotta Hak,
Nihei Kenji,
Abe Yuichi,
Kato Seiichi,
Jiang DaPeng,
NaganoFujii Motoko,
Sada Kiyonao
Publication year - 2006
Publication title -
microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0385-5600
DOI - 10.1111/j.1348-0421.2006.tb03822.x
Subject(s) - subacute sclerosing panencephalitis , measles virus , virology , biology , virus , mutation , point mutation , mutant , stop codon , gene , morbillivirus , coding region , somatic hypermutation , paramyxoviridae , genetics , measles , viral disease , antibody , b cell , vaccination
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 protein‐coding 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.