SEQUENCE DIVERSITY WITHIN THE REOVIRUS S2 GENE - REOVIRUS GENES REASSORT IN NATURE, AND THEIR TERMINI ARE PREDICTED TO FORM A PANHANDLE MOTIF
SEQUENCE DIVERSITY WITHIN THE REOVIRUS S2 GENE - REOVIRUS GENES REASSORT IN NATURE, AND THEIR TERMINI ARE PREDICTED TO FORM A PANHANDLE MOTIF
复制标题
DOI：
10.1128/jvi.68.2.750-756.1994
复制
发表时间：
1994-02-01
影响因子：
5.4
通讯作者：
DERMODY, TS
中科院分区：
文献类型：
--
作者：
CHAPPELL, JD;GORAL, MI;DERMODY, TS
为了更好地了解哺乳动物呼肠孤病毒的遗传多样性，我们测定了9株呼肠孤病毒的S2核苷酸和推导的sigma 2氨基酸序列，并将其与3种呼肠孤病毒血清型的原型株的序列进行了比较。S2基因和Sigma 2蛋白在所研究的4株1型、1株2型和7株3型毒株中高度保守。基于12株呼肠孤病毒S2核苷酸序列的系统发育分析表明，S2基因的多样性与病毒血清型无关。此外，我们还发现7株3型毒株的S1和S2基因核苷酸序列构建的系统发育树之间存在明显的拓扑差异。这些结果表明呼肠孤病毒ST和S2基因具有不同的进化历史，从而为呼肠孤病毒基因在自然界中的侧向转移提供了系统发育证据。在同义位置分析12西格玛2编码的S2核苷酸序列的变异性时，我们发现与其他西格玛2编码区相比，5‘端约60个核苷酸和3’端约30个核苷酸明显保守。对RNA二级结构的预测表明，更保守的S2序列参与了双链RNA延伸区域的形成，该区域被一对茎环打断。在12个推导的sigma-2氨基酸序列中，只有11%的氨基酸发生了替换。这一发现表明，对sigma 2结构或功能的限制，可能部分是因为它在病毒核心中的位置，限制了该蛋白质的序列多样性。
To better understand genetic diversity within mammalian reoviruses, we determined S2 nucleotide and deduced sigma 2 amino acid sequences of nine reovirus strains and compared these sequences with those of prototype strains of the three reovirus serotypes. The S2 gene and sigma 2 protein are highly conserved among the four type 1, one type 2, and seven type 3 strains studied. Phylogenetic analyses based on S2 nucleotide sequences of the 12 reovirus strains indicate that diversity within the S2 gene is independent of viral serotype. Additionally, we found marked topological differences between phylogenetic trees generated from S1 and S2 gene nucleotide sequences of the seven type 3 strains. These results demonstrate that reovirus ST and S2 genes have distinct evolutionary histories, thus providing phylogenetic evidence for lateral transfer of reovirus genes in nature. When variability among the 12 sigma 2-encoding S2 nucleotide sequences was analyzed at synonymous positions, we found that approximately 60 nucleotides at the 5' terminus and 30 nucleotides al the 3' terminus were markedly conserved in comparison with other sigma 2-encoding regions of S2. Predictions of RNA secondary structures indicate that the more conserved S2 sequences participate in the formation of an extended region of duplex RNA interrupted by a pair of stem-loops. Among the 12 deduced sigma 2 amino acid sequences examined, substitutions were observed at only 11% of amino acid positions. This finding suggests that constraints on the structure or function of sigma 2, perhaps in part because of its location in the virion core, have limited sequence diversity within this protein.