The matrix gene expression of subacute sclerosing panencephalitis (SSPE) virus (Osaka-1 strain): A comparison of two sibling viruses isolated from different lobes of an SSPE brain
M. Ayata et al., The matrix gene expression of subacute sclerosing panencephalitis (SSPE) virus (Osaka-1 strain): A comparison of two sibling viruses isolated from different lobes of an SSPE brain, MICROB IMMU, 42(11), 1998, pp. 773-780
The Fr/V and Oc/V sibling viruses of the Osaka-1 strain of the subacute scl
erosing panencephalitis (SSPE) virus were defective in cell-free virus prod
uction. By radioimmunoprecipitation assay, the matrix (M) protein was not d
etected in cells persistently infected with the Osaka-1 strain. This undete
ctable expression was consistent with the selective reduction of antibody r
esponse to the M protein in the patient from whom the Osaka-1 strain was is
olated. The sequence of the M gene, however, predicted that the protein cou
ld be synthesized because the translational start and stop codons for the p
rotein were not altered, Northern blot hybridization demonstrated the selec
tive defect of the monocistronic mRNAs for the M protein and the phosphopro
tein (P) together with the dominant presence of the P-M bicistronic mRNA, T
his absence of the hi mRNA was further confirmed by primer extension analys
is. Therefore, the undetectable expression of the M protein in the infected
cells was proved to be caused by a transcriptional defect, The two sibling
viruses, isolated from remote portions of an SSPE brain, were indistinguis
hable in their viral characters, including the M gene sequences, which indi
cates the possibility of clonal expansion of the strain in the brain.