Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
Structure. 2010 Dec 8;18(12):1579-86. doi: 10.1016/j.str.2010.10.005.
We applied whole-cell electron cryotomography to the archaeon Sulfolobus infected by Sulfolobus turreted icosahedral virus (STIV), which belongs to the PRD1-Adeno lineage of dsDNA viruses. STIV infection induced the formation of pyramid-like protrusions with sharply defined facets on the cell surface. They had a thicker cross-section than the cytoplasmic membrane and did not contain an exterior surface protein layer (S-layer). Intrapyramidal bodies often occupied the volume of the pyramids. Mature virions, procapsids without genome cores, and partially assembled particles were identified, suggesting that the capsid and inner membrane coassemble in the cytoplasm to form a procapsid. A two-class reconstruction using a maximum likelihood algorithm demonstrated that no dramatic capsid transformation occurred upon DNA packaging. Virions tended to form tightly packed clusters or quasicrystalline arrays while procapsids mostly scattered outside or on the edges of the clusters. The study revealed vivid images of STIV assembly, maturation, and particle distribution in cell.
我们应用全细胞电子晶体学研究了感染了火球菌病毒（STIV）的火球菌，火球菌病毒属于双链 DNA 病毒的 PRD1-Adeno 谱系。STIV 感染诱导细胞表面形成金字塔形突起，具有明显的面。它们的横截面比细胞质膜厚，并且不含有外表面蛋白层（S-层）。在金字塔内经常有内聚体占据空间。鉴定出成熟的病毒粒子、没有基因组核心的原衣壳和部分组装的颗粒，表明衣壳和内膜在细胞质中共同组装形成原衣壳。使用最大似然算法的双类重建表明，在 DNA 包装过程中没有发生明显的衣壳转化。病毒粒子倾向于形成紧密堆积的簇或准晶阵列，而原衣壳大多散布在簇的外部或边缘。该研究揭示了 STIV 在细胞内组装、成熟和颗粒分布的生动图像。
