The sequences of the reovirus serotype 1, 2, and 3 L1 genome segments and analysis of the mode of divergence of the reovirus serotypes.
The sequences of the reovirus serotype 1, 2, and 3 L1 genome segments and analysis of the mode of divergence of the reovirus serotypes.
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DOI：
10.1016/0042-6822(89)90055-x
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发表时间：
1989-03
期刊：
影响因子：
3.7
通讯作者：
Jon R. Wiener;W. Joklik
中科院分区：
文献类型：
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作者：
Jon R. Wiener;W. Joklik
我们报道了呼肠孤病毒血清3型株Dearing的L1基因组片段序列，该片段编码次要核心成分蛋白λ3。它长3854 *，有一个长长的开放阅读框，从19号位置开始，长度为1267个密码子。蛋白质λ3与任何其他蛋白质没有明显的相关性，也不具有指示公认的特化功能的基序。我们还对呼肠孤病毒血清型1和血清型2的L1基因组片段进行了测序。血清1型和3型L1基因组片段相关性极近；只有154个错配（4.1%），其中80%在第三碱基密码子位置，因此这两个λ3蛋白的相关性为98.3%（1267个错配中只有22个）。血清2型L1基因组片段与血清1型和3型基因组片段的相关性仅为75%，血清2型λ3蛋白与血清1型和3型λ3蛋白的相关性为92%。我们还分析了呼肠孤病毒基因组片段进化成三种血清型的分化模式。似乎早在血清型1和血清型3分化之前，血清型2就从血清型13前体分离出来了。在所有的情况下，第三个碱基密码子的位置在不同的基因组片段已经偏离约80%的随机性。第一和第二碱基密码子位置的差异要小得多，而且程度不同，这可能取决于每种蛋白质在不显著丧失功能的情况下接受变化的能力。对于血清型1和血清型3的分离，各种基因组的差异程度在一个非常大的范围内变化。S1基因组片段再次出现了最广泛的分化，第一、第二和第三碱基密码子位置的分化程度分别约为50%、35%和75%。对于其他7个基因组片段，我们研究的第三碱基密码子位置差异程度分别为56,53,48,29,22,13和6%，而第一和第二碱基密码子位置差异的范围分别为不超过6%至2%和3%至不到1%。对这些模式最可能的解释是，各种基因组片段在进化过程中的不同时间分离为今天的血清型1和血清型3相关形式，这些祖先是基因组片段重组，其存活率与同源基因组片段集相同或更高。
We report the sequence of the L1 genome segment of reovirus serotype 3 strain Dearing, which encodes the minor core component protein λ3. It is 3854 by long, with a long open reading frame starting at position 19 that is 1267 codons long. Protein λ3 is not detectably related to any other protein, nor does it appear to possess motifs indicative of recognized specialized functions. We have also sequenced the L1 genome segments of reovirus serotypes 1 and 2. The serotype 1 and 3 L1 genome segments are extremely closely related; there are only 154 mismatches (4.1%), 80% of which are in third base codon positions, so that these two λ3 proteins are 98.3% related (only 22 mismatches out of 1267). The serotype 2 L1 genome segment is only 75% related to the serotype 1 and 3 genome segments, and the serotype 2 λ3 protein is 92% related to the serotype 1 and 3 λ3 proteins. We have also analyzed the divergence patterns by which the various reovirus genome segments evolved into the three serotype forms. It appears that serotype 2 separated from the serotype 1 3 precursor long before serotypes 1 and 3 themselves diverged. In all cases the third base codon positions in the various genome segments have diverged about 80% toward randomness. The first and second base codon positions have diverged much less and to varying degree, depending, presumably, on each protein's ability to accept changes without significant loss of function. For the separation into the serotype 1 and 3 forms, the extent of divergence of the various genome varies over a very wide range. The S1 genome segments have again diverged most extensively, the extent of divergence in the first, second, and third base codon positions being about 50, 35 and 75%, respectively. For seven other genome segments that we examined the extent of third base codon position divergence is 56, 53, 48, 29, 22, 13, and 6%, whereas first and second base codon position divergence ranges from no more than 6 to 2 and 3 to less than 1%, respectively. The most likely explanation of these patterns is that the separation of the various genome segments into the present-day serotype 1 and 3 associated forms occurred at different times during evolution, from progenitors that were genome segment reassortants with survival rates as high as or higher than those of homologous genome segment sets.