Morphogenesis of sandfly fever viruses (Bunyaviridae family)
Morphogenesis of sandfly fever viruses (Bunyaviridae family)
复制标题
白蛉热病毒（布尼亚病毒科）的形态发生
DOI：
10.1016/0042-6822(82)90118-0
复制
发表时间：
1982
期刊：
影响因子：
3.7
通讯作者：
D. Pifat
中科院分区：
文献类型：
--
作者：
Jonathan F Smith;D. Pifat
白蛉热病毒形态发生中发生的事件已通过薄片电子显微镜和病毒特异性多肽与受感染细胞膜的关联分析进行了检查。研究人员对两种具有代表性的白蛉热病毒——卡里马巴德病毒（KV）和蓬塔托罗病毒（PTV）进行了研究，它们在病毒体结构（通过负染色监测）和形态发生（在受感染的 Vero 细胞薄片中观察到）方面似乎无法区分。对纯化的、戊二醛固定的病毒粒子进行钼酸铵负染色，显示其基本上为球形颗粒，直径为 87 nm，其中表面蛋白被构建成紧密堆积的中空圆柱形亚基，直径为 10-11 nm，长度为 9-10 nm。这些表面单元位于 7 纳米膜双层的外围，该双层膜围绕着可变电子密度的核。正如在受感染细胞的薄切片中所见，这些颗粒的组装在感染后 12 小时首次检测到，仅发生在光滑膜囊泡中，并且主要发生在高尔基体池中或附近的膜上。通过将修饰的膜片段连续卷入（出芽）到这些囊泡的内腔中，形成形态成熟的颗粒。病毒核糖核蛋白（RNP）在细胞质中未观察到游离状态，但在这些囊泡的细胞质面凝结在对侧（腔）面可观察到病毒刺突结构的区域。在囊泡膜或其他膜的相邻部分上观察不到 RNP 和刺突结构，这些膜不直接参与出芽病毒粒子的组装。对从受感染细胞制备的未分级膜囊泡中的病毒多肽进行分析表明，KV 特异性包膜和核衣壳蛋白迅速与膜结合，而非结构多肽仅在细胞质级分中发现。这些囊泡的胰凝乳蛋白酶处理表明至少一种病毒糖蛋白被插入到细胞膜中，使得其大约12%的序列保留在细胞质膜表面。该序列的蛋白水解去除产生了可免疫沉淀的糖基化片段，该片段通过其在囊泡内的定向而免受进一步的蛋白水解。这些形态学和生化数据已用于构建这些病毒的组装模型。病毒颗粒通过胞吐作用从受感染的细胞中释放出来，该过程似乎不会导致病毒抗原对细胞表面膜的显着修饰。
The events occurring in the morphogenesis of sandfly fever viruses have been examined by thin-section electron microscopy and by an analysis of the association of virus-specific polypeptides with membranes of infected cells. Two representative sandfly fever viruses have been studied, Karimabad virus (KV) and Punta Toro virus (PTV), which appeared indistinguishable both in terms of virion structure, as monitored by negative staining, and morphogenesis, as observed in thin sections of infected Vero cells. Ammonium molybdate negative staining of purified, glutaraldehyde-fixed virions revealed essentially spherical particles, 87 nm in diameter, in which the surface proteins were constructed into closely packed, hollow, cylindrical subunits measuring 10–11 nm in diameter and 9–10 nm in length. These surface units are located peripherally to a 7-nm membrane bilayer which surrounds a nucleoid of variable electron density. As seen in thin sections of infected cells, the assembly of these particles was first detected at 12 hr after infection, occurred exclusively at smooth membrane vesicles, and predominantly at membranes in, or adjacent to, Golgi cisternae. Morphologically mature particles were formed by continuous involution (budding) of modified membrane segments into the lumen of these vesicles. Viral ribonucleoprotein (RNP), which was not observed free in the cytoplasm, condensed at the cytoplasmic face of these vesicles at areas at which viral spike structures could be observed at the contralateral (luminal) face. Neither RNP nor spike structures could be observed on adjacent sections of the vesicular membrane, or other membranes, which were not directly involved in the assembly of a budding virion. Analysis of the viral polypeptides in unfractionated membrane vesicles prepared from infected cells demonstrated that KV-specific envelope and nucleocapsid proteins rapidly became membrane bound, whereas a nonstructural polypeptide was found only in cytoplasmic fractions. Chymotrypsin treatment of these vesicles has indicated that at least one viral glycoprotein is inserted into cellular membranes such that approximately 12% of its sequence remains at the cytoplasmic membrane face. Proteolytic removal of this sequence generated an immunoprecipitable, glycosylated fragment which was protected from further proteolysis by its orientation within the vesicle. These morphologic and biochemical data have been used to construct a model for the assembly of these viruses. Virus particles are released from infected cells by exocytosis, a process which does not appear to result in significant modification of cell surface membranes with viral antigens.
影响因子：
56.9
作者：
ROTHMAN, JE
通讯作者：
ROTHMAN, JE