Molecular genetics of subactute sclerosing panencephalitis (SSPE) virus

(1)对SSPE病毒Yamagata-1株进行了基因分析。测定了M、NP、H和F基因的完整碱基序列以及L和P基因的部分序列。(2)NP-L的双顺反子mRNA在cDNA文库中表达最丰富。该基因可分为两种类型，一种是NP基因865 bp，L基因1293 bp，另一种是NP基因187 bp，L基因1192 bp。这种双顺反子mRNA迄今尚未报道。(3)发现对应于SSPE病毒HA的外包膜突起的末端的羧基末端的氨基酸序列与特异性结合烟碱乙酰胆碱的长神经毒素的活性结构域具有高度的同源性。该结构域与SSPE病毒和麻疹病毒的HA抗原性交叉反应。此外，SSPE患者对该结构域具有显著高滴度的抗体。因此，HA的该表位被认为在病毒在脑中的跨突触传播中起重要作用。

(1) Gene analysis of SSPE virus, Yamagata-1 strain, was conducted. The entire base sequences of M, NP, H, and F genes as well as part of the sequences of L and P genes were determined.(2) Di-cistronic mRNA of NP-L was most abundantly observed in cDNA library. It was classified into two types; the one consisting of 865 bp of NP and 1293 bp of L, and the other consisting of 187 bp of NP and 1192 bp of L. Such di-cistronic mRNA has not been reported thus far.(3) The amino acid sequence of the carboxy terminus corresponding to the end of the outer envelope projection of HA of SSPE virus was found to have a high degree of homology with the active domain of long neurotoxin which specifically binds to the nicotini acetylcholine.receptor. This domain was shown to cross-react with HA of SSPE virus and of measles virus antigenically. In addition, SSPE patients had significantly high titers of antibody to this domain. Thus, this epitope of HA is considered to play an important role in the transsynaptic spreading of the virus in the brain.