Babiss L E, Luftig R B, Weatherbee J A, Weihing R R, Ray U R, Fields B N
J Virol. 1979 Jun;30(3):863-74. doi: 10.1128/JVI.30.3.863-874.1979.
Utilizing negative-stain electron microscopy in which similar concentrations of reovirus types 1 and 3 are incubated with a carbon support film containing chick brain, rabbit brain, or HeLa cell microtubules, 81% of the type 1 and 56% of type 3 exhibited an association with the apparent "edge" of the microtubule. This implies that there is a high level of specific affinity for type 1 but not for type 3 to microtubules, since it has previously been determined that only 50% of randomly associated particles would be associated with the edge. The high edge binding of reovirus type 1 is virtually independent of the origin of microtubule, or of whether microtubules or virus has been initially adhered to the support film. On the other hand, reovirus type 1-specific antiserum reduced the edge binding or reovirus type 1 to 45%, whereas type 3 specific antiserum caused no less (within the variability of the assay) of the edge binding of reovirus type 1 to microtubules (76% edge bound). High edge binding of reovirus type 1 to microtubules is correlated with the presence of type 1 or sigma 1 polypeptide. This minor outer capsid polypeptide is encoded in the S1 double-stranded RNA segment and is the viral hemagglutinin and neutralization antigen. Recombinant reovirus clones containing the S1 double-stranded RNA segment of type 1 (80 and 802) show about 85% edge binding, as compared to a value of 42% for clones and the S1 gene of type 3 (204. Electron microscopy of purified reovirus types 1 and 3 by negative staining reveals that type 1 and 802 capsomers are distinctly visualized, whereas those of type 3 and 204 appear diffuse. Thus, the greater in vitro binding of type 1 to microtubules may reflect an increased accessibility of certain of its outer capsomers, and thereby, sigma 1 polypeptides to microtubules. Examination of its outer sections of reovirus type 1- and 3-infected cells at 24 to 48 h postinfection at 31 degrees C showed that about eight times as many viral factoris in type 1-infected cells exhibited an extensive association of virus particles with microtubules, as compared to viral factories of type 3-infected cells. Thus, both in vivo and in vitro there appears to be a greater specificity for the association of reovirus type 1 particles with microtubules, as compared to reovirus type 3 particles.
利用负染电子显微镜技术，将相似浓度的1型和3型呼肠孤病毒与含有鸡脑、兔脑或HeLa细胞微管的碳支持膜一起孵育，结果显示，1型病毒中有81%、3型病毒中有56%与微管的明显“边缘”存在关联。这意味着1型病毒对微管具有高度的特异性亲和力，而3型病毒则不然，因为此前已确定，随机结合的颗粒中只有50%会与边缘结合。1型呼肠孤病毒的高边缘结合几乎与微管的来源无关，也与微管或病毒最初是否附着在支持膜上无关。另一方面，1型呼肠孤病毒特异性抗血清将1型呼肠孤病毒的边缘结合率降低至45%，而3型特异性抗血清对1型呼肠孤病毒与微管的边缘结合率（边缘结合率为76%）在检测的变异性范围内没有降低。1型呼肠孤病毒与微管的高边缘结合与1型或σ1多肽的存在相关。这种次要的外衣壳多肽由S1双链RNA片段编码，是病毒血凝素和中和抗原。含有1型S1双链RNA片段的重组呼肠孤病毒克隆（80和802）显示约85%的边缘结合率，相比之下，含有3型（204）S1基因的克隆的边缘结合率为42%。通过负染对纯化的1型和3型呼肠孤病毒进行电子显微镜观察发现，1型和802的衣壳粒清晰可见，而3型和204的衣壳粒则显得模糊。因此，1型病毒在体外与微管的更强结合可能反映了其某些外衣壳粒以及σ1多肽与微管的可及性增加。在31℃感染后24至48小时对1型和3型呼肠孤病毒感染细胞的外部区域进行检查发现，与3型感染细胞的病毒工厂相比，1型感染细胞中约有八倍之多的病毒工厂显示病毒颗粒与微管存在广泛关联。因此，与3型呼肠孤病毒颗粒相比，1型呼肠孤病毒颗粒在体内和体外与微管的结合似乎都具有更高的特异性。
