Kawakami Shigeki, Watanabe Yuichiro, Beachy Roger N
Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, MO 63132, USA.
Proc Natl Acad Sci U S A. 2004 Apr 20;101(16):6291-6. doi: 10.1073/pnas.0401221101. Epub 2004 Apr 12.
Plant viruses encode movement proteins (MPs) that facilitate cell-cell transport of infection through plasmodesmata. Intracellular and intercellular spread of virus replication complexes (VRCs) of tobacco mosaic virus was followed in intact leaf tissue from 12 to 36 h post infection (hpi) by using confocal microscopy. From 12 hpi, VRCs in primary infected cells were associated with cortical endoplasmic reticulum, and at 14 hpi, exhibited high intracellular mobility ( approximately 160 nm/sec); mobility was slowed between 14 and 16 hpi ( approximately 40 nm/sec), and by 18 hpi, VRCs were stationary, adjacent to plasmodesmata. VRCs traversed the plasmodesmata between 18 and 20 hpi. The process of formation and movement of VRCs was repeated in adjacent cells in 3-4 h vs. 20 h from primary infected cells. The rapid intracellular movement of the VRCs and the spread to adjacent cells was blocked by inhibitors of filamentous actin and myosin, but not by inhibitors of microtubules. We propose a model whereby cell-cell spread of tobamovirus infection is accomplished by subviral replication complexes that initiate TMV replication immediately after entry to adjacent cells.
植物病毒编码运动蛋白（MPs），这些蛋白有助于病毒感染通过胞间连丝进行细胞间运输。通过共聚焦显微镜观察了烟草花叶病毒的病毒复制复合体（VRCs）在感染后12至36小时（hpi）完整叶片组织中的细胞内和细胞间传播情况。在感染后12小时，初次感染细胞中的VRCs与皮质内质网相关联，在14 hpi时，表现出较高的细胞内移动性（约160 nm/秒）；在14至16 hpi之间移动性减慢（约40 nm/秒），到18 hpi时，VRCs静止，靠近胞间连丝。VRCs在18至20 hpi之间穿过胞间连丝。与初次感染细胞相比，VRCs的形成和移动过程在相邻细胞中以3 - 4小时的间隔重复进行，而不是20小时。VRCs的快速细胞内移动以及向相邻细胞的传播被丝状肌动蛋白和肌球蛋白的抑制剂阻断，但未被微管抑制剂阻断。我们提出了一个模型，即烟草花叶病毒感染的细胞间传播是由亚病毒复制复合体完成的，这些复合体在进入相邻细胞后立即启动TMV复制。
