Nature of the 3'-terminal sequences of the plus and minus strands of the S1 gene of reovirus serotypes 1, 2 and 3.
Nature of the 3'-terminal sequences of the plus and minus strands of the S1 gene of reovirus serotypes 1, 2 and 3.
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呼肠孤病毒血清型 1、2 和 3 的 S1 基因正链和负链 3 末端序列的性质。
DOI：
10.1016/0042-6822(80)90154-3
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发表时间：
1980
期刊：
影响因子：
3.7
通讯作者：
Joklik,WK
中科院分区：
文献类型：
--
作者：
Li,JK;Keene,JD;Scheible,PP;Joklik,WK
对呼肠孤病毒血清型1、2、3的S1基因正、负链3′端进行了测序。S1基因编码多肽σ1，这是一种分子量约为45000的蛋白，可产生主要的中和抗体，是细胞附着蛋白血凝素，是呼肠孤病毒毒力、组织亲和性和致病性的主要决定因素。它是所有呼肠孤病毒蛋白中最具类型特异性的；因此，对编码它的基因的检查应该最好地揭示它的哪些序列是保守的（恒定的），哪些可能是变化的。呼肠孤病毒血清型1、2和3的S1基因正链的3 '末端具有广泛的同源性。它们共享前20或21个核苷酸中的16个，包括末端序列UCAUC-3 '，以及在残基40附近含有终止密码子的额外5个残基区域。S1基因另一端（包含正链5′端）的同源性程度较低；所有s1 +链具有相同的序列5'-GCUAUU，血清型1和2 s1 +链具有额外的CGC。接下来的序列没有同源性，直到第一个起始密码子分别在残基14、14或13处遇到。由三个S1基因编码的前20到30个氨基酸没有可检测到的同源性，尽管它们表现出相似程度的疏水性。三个sl +链表现出有趣的二级结构特征。在两端的100个残基内很少有稳定的发夹；血清型2的sl +链中有一个这样的发夹，它可能具有一定的稳定性（- 13.0 kcal），包含三个相内终止密码子，但这种结构在血清型1和3的sl +链中不存在。在所有三种sl +链的5 ‘和3 ’末端附近（但不是直接在那里）存在互补区域，可以想象这可能允许环状化（- 15.0 kcal）。此外，血清型1和2（而不是3）的sl +链在其5 ‘端附近具有一个序列，该序列与紧接在18s核糖体RNA 3 ’端附近的序列互补。这些研究表明，尽管S1基因编码一种非常类型特异性的蛋白质，但在呼肠孤病毒血清型1、2和3中存在的三种形式的S1基因在其末端具有相当大的同源区域。这些区域可能是核糖体、RNA聚合酶（转录酶和复制酶）和衣壳化的识别信号。
The 3′-terminal regions of the plus and minus strands of the S1 genes of serotypes 1, 2, and 3 of reovirus were sequenced. The S1 gene codes for polypeptide σ1, a protein with a MW of about 45,000 that elicits the principal neutralizing antibody and is the hemagglutinin, the cell attachment protein, and the primary determinant of reovirus virulence, tissue tropism, and pathogenicity. It is the most type specific of all reovirus proteins; examination of the gene that encodes it should therefore best reveal which of its sequences are conserved (constant) and which may be varied. The 3′-termini of the plus strands of the S1 genes of reovirus serotypes 1, 2, and 3 share extensive homology. They share 16 of the first 20 or 21 nucleotides including the terminal sequence UCAUC-3′, as well as an additional 5-residue region near residue 40 that contains a termination codon. The extent of homology at the other end of the S1 gene (that which contains the 5′-ends of the plus strands) is less extensive; all plus strands possess the same sequence 5'-GCUAUU and serotypes 1 and 2 s1 plus strands share an additional CGC. There follows a sequence with no homology until the first initiation codon is encountered at residue 14, 14, or 13, respectively. The first 20 to 30 amino acids encoded by the three S1 genes show no detectable homology, although they exhibit a similar degree of hydrophobicity. The three sl plus strands exhibit interesting secondary structure features. Few stable hairpins are present within 100 residues of either terminus; one such hairpin in the sl plus strand of serotype 2 that may possess some stability (−13.0 kcal) encompasses three in-phase termination codons, but this structure is not present in the sl plus strands of serotypes 1 and 3. There are regions of complementarity near (but not directly at) the 5′- and 3′-termini of all three species of sl plus strands that may conceivably permit circularization (−15.0 kcal). Further, the sl plus strands of serotypes 1 and 2, but not 3, possess a sequence near their 5′-terminus that is complementary to a sequence immediately adjacent to the 3′-terminus of 18 S ribosomal RNA. These studies indicate that although the S1 gene codes for a very type-specific protein, the three forms of it that are present in reovirus serotypes 1, 2, and 3 nevertheless possess considerable regions of homology at their termini. These regions probably function as recognition signals for ribosomes, RNA polymerase (transcriptase and replicase), and encapsidation.