Elevating fitness after a horizontal gene exchange in bacteriophage φX174
Elevating fitness after a horizontal gene exchange in bacteriophage φX174
复制标题
噬菌体水平基因交换后提高适应性 ÏX174
DOI：
10.1016/j.virol.2016.10.029
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发表时间：
2017
期刊：
影响因子：
3.7
通讯作者：
Fane, Bentley A.
中科院分区：
文献类型：
--
作者：
Doore, Sarah M.;Schweers, Nicholas J.;Fane, Bentley A.
在一项早期研究中，通过将编码主要刺突蛋白的噬菌体 G4 G 基因放入 φX174 基因组中，研究了基于蛋白质的水平基因转移障碍。外源 G 蛋白促进旁路组装反应，导致致命表型。经过三次靶向遗传选择后，两种外源刺突蛋白之一被有效地整合到 φX174 系统中：完整的 G4 或重组 G4/φX174 蛋白（94% G4:6% φX174）。然而，应变适应度非常低。在这项研究中，对嵌合体进行了表征并进行了实验进化。组装效率低下是低适应性的主要原因：因此，影响组装的突变恢复了适应性。祖先和进化菌株的刺突蛋白偏好是在外来蛋白和 φX174 G 蛋白之间的竞争实验中确定的。在适应之前，两种 G 蛋白都被整合到病毒粒子中；此后，外来蛋白质受到强烈青睐。因此，先前的抑制性蛋白质成为组装过程中的首选底物。
In an earlier study, protein-based barriers to horizontal gene transfer were investigated by placing the bacteriophage G4 G gene, encoding the major spike protein, into the φX174 genome. The foreign G protein promoted off-pathway assembly reactions, resulting in a lethal phenotype. After three targeted genetic selections, one of two foreign spike proteins was productively integrated into the φX174 system: the complete G4 or a recombinant G4/φX174 protein (94% G4:6% φX174). However, strain fitness was very low. In this study, the chimeras were characterized and experimentally evolved. Inefficient assembly was the primary contributor to low fitness: accordingly, mutations affecting assembly restored fitness. The spike protein preference of the ancestral and evolved strains was determined in competition experiments between the foreign and φX174 G proteins. Before adaptation, both G proteins were incorporated into virions; afterwards, the foreign proteins were strongly preferred. Thus, a previously inhibitory protein became the preferred substrate during assembly.