Bosse Jens B, Hogue Ian B, Feric Marina, Thiberge Stephan Y, Sodeik Beate, Brangwynne Clifford P, Enquist Lynn W
Department of Molecular Biology, Princeton University, Princeton, NJ 08544; Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544;
Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544;
Proc Natl Acad Sci U S A. 2015 Oct 20;112(42):E5725-33. doi: 10.1073/pnas.1513876112. Epub 2015 Oct 5.
The nuclear chromatin structure confines the movement of large macromolecular complexes to interchromatin corrals. Herpesvirus capsids of approximately 125 nm assemble in the nucleoplasm and must reach the nuclear membranes for egress. Previous studies concluded that nuclear herpesvirus capsid motility is active, directed, and based on nuclear filamentous actin, suggesting that large nuclear complexes need metabolic energy to escape nuclear entrapment. However, this hypothesis has recently been challenged. Commonly used microscopy techniques do not allow the imaging of rapid nuclear particle motility with sufficient spatiotemporal resolution. Here, we use a rotating, oblique light sheet, which we dubbed a ring-sheet, to image and track viral capsids with high temporal and spatial resolution. We do not find any evidence for directed transport. Instead, infection with different herpesviruses induced an enlargement of interchromatin domains and allowed particles to diffuse unrestricted over longer distances, thereby facilitating nuclear egress for a larger fraction of capsids.
核染色质结构将大型大分子复合物的运动限制在染色质间的围栏内。大约125纳米的疱疹病毒衣壳在核质中组装，必须到达核膜才能出芽。先前的研究得出结论，核内疱疹病毒衣壳的运动是活跃的、有方向的，且基于核丝状肌动蛋白，这表明大型核复合物需要代谢能量来逃离核内的束缚。然而，这一假设最近受到了挑战。常用的显微镜技术无法以足够的时空分辨率对快速的核颗粒运动进行成像。在这里，我们使用一种旋转的倾斜光片，我们将其称为环形光片，以高时空分辨率对病毒衣壳进行成像和追踪。我们没有发现任何定向运输的证据。相反，感染不同的疱疹病毒会导致染色质间结构域扩大，并使颗粒能够在更长的距离上不受限制地扩散，从而促进更大比例的衣壳从核内逸出。
