Identification of defects in the neuraminidase gene of four temperature-sensitive mutants of A/WSN/33 influenza virus.
Identification of defects in the neuraminidase gene of four temperature-sensitive mutants of A/WSN/33 influenza virus.
复制标题
A/WSN/33 流感病毒四种温度敏感突变体神经氨酸酶基因缺陷的鉴定。
DOI：
10.1016/0042-6822(86)90432-0
复制
发表时间：
1986
期刊：
影响因子：
3.7
通讯作者：
Nayak,DP
中科院分区：
文献类型：
--
作者：
Bos,TJ;Nayak,DP
四种流感（A/WSN/33）突变体，对神经氨酸酶（NA）温度敏感（ts）（Sugiuraet al.，1972年，1975年）。在非允许温度（39.5°）下，所有四种ts突变体都表现出酶活性和向细胞表面转运的缺陷。当温度降至允许温度（33°）时，酶活性和向细胞表面的转运均恢复，表明突变缺陷是可逆的。NA基因的TS突变体，其回复突变体和野生型WSN病毒的比较序列分析表明，在每种情况下，单点突变引起的氨基酸取代与TS缺陷。每个点突变的位置时，映射在三维结构的NA变化。然而，所有四个氨基酸取代均位于头部区域的β折叠链中。在每个突变体NA中发现了对TS表型不重要的其他几个氨基酸变化。非必要的变化位于柄区或头部的环状结构中，但在β折叠链中没有。由于酶的活性和运输的NA在所有四个突变体的影响，我们建议，突变表型是由整体构象的变化，而不是在唾液酸结合位点的局部变化。
Four influenza (A/WSN/33) mutants, temperature sensitive (ts) for neuraminidase (NA) (Sugiuraet al., 1972, 1975) were analyzed. All four ts mutants were found to be defective at the nonpermissive temperature (39.5°) both in enzymatic activity and in transport to the cell surface. Upon shift down to the permissive temperature (33°), enzymatic activity and transport to the cell surface were both restored suggesting that the mutational defect is reversible. Comparative sequence analysis of the NA gene from ts mutants, their revertants and wild type WSN viruses revealed that in each case single point mutations causing amino acid substitutions were associated with the ts defect. The positions of each point mutation when mapped in the three-dimensional structure of NA varied. However, all four amino acid substitutions were located in β-sheet strands of the head region. Several other amino acid changes not essential for the ts phenotype were found in each mutant NA. The nonessential changes were localized either in the stalk region or in the loop structures of the head, but none in the β-sheet strands. Because both enzymatic activity and transport of NA were affected in all four mutants, we propose that the mutational phenotype is caused by a change in overall conformation rather than a localized change in the sialic acid binding site.