Jayasuriya A K, Nibert M L, Fields B N
Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115.
Virology. 1988 Apr;163(2):591-602. doi: 10.1016/0042-6822(88)90300-5.
The nucleotide sequence of the M2 gene segment of the mammalian reovirus prototype strain, type 3 Dearing, was determined from a cloned full-length cDNA copy of the viral double-stranded RNA segment. The gene comprises 2203 nucleotides and has a single long open reading frame that spans bases 30 through 2154 and encodes the 708 amino acid outer capsid protein mu 1. Aminoterminal sequence analysis of mu 1C, the proteolytically cleaved form of mu 1 that is found in purified reovirions, has identified the site of mu 1 to mu 1C cleavage between residues 42 and 43 in the mu 1 sequence. Aminoterminal sequence analysis of delta, the proteolytically cleaved product of mu 1C that is found in chymotrypsin-generated intermediate subviral particles, has indicated that the mu 1C to delta cleavage occurs near the carboxyterminus of mu 1C. Lastly, stoichiometric determinations using new sequence information have suggested that approximately equimolar amounts of mu 1C and the other major outer capsid component sigma 3 are present in virions. The data presented in this study should be useful for understanding the molecular basis of the functions of the mu 1 protein in reovirus entry into cells and in pathogenesis in the host animal.
从病毒双链RNA片段的克隆全长cDNA拷贝中确定了哺乳动物呼肠孤病毒原型株3型迪林（type 3 Dearing）M2基因片段的核苷酸序列。该基因由2203个核苷酸组成，有一个单一的长开放阅读框，跨度为第30至2154个碱基，编码708个氨基酸的外衣壳蛋白μ1。对μ1C（在纯化的呼肠孤病毒中发现的经蛋白水解切割的μ1形式）的氨基末端序列分析，确定了μ1序列中第42和43位残基之间μ1至μ1C的切割位点。对δ（在胰凝乳蛋白酶产生的中间亚病毒颗粒中发现的μ1C的蛋白水解切割产物）的氨基末端序列分析表明，μ1C至δ的切割发生在μ1C的羧基末端附近。最后，利用新的序列信息进行的化学计量测定表明，病毒粒子中μ1C和另一种主要外衣壳成分σ3的含量大致等摩尔。本研究中呈现的数据应有助于理解μ1蛋白在呼肠孤病毒进入细胞以及在宿主动物发病机制中的功能的分子基础。
