Hirabayashi Ai, Muramoto Yukiko, Takenaga Toru, Tsunoda Yugo, Wakazaki Mayumi, Sato Mayuko, Fujita-Fujiharu Yoko, Nomura Norimichi, Yamauchi Koji, Onishi Chiho, Nakano Masahiro, Toyooka Kiminori, Noda Takeshi
Laboratory of Ultrastructural Virology, Institute for Life and Medical Sciences, Kyoto University, Kyoto, Kyoto Prefecture, Japan.
CREST, Japan Science and Technology Agency, Kawaguchi, Saitama Prefecture, Japan.
mBio. 2025 Jan 8;16(1):e0333124. doi: 10.1128/mbio.03331-24. Epub 2024 Nov 29.
SARS-CoV-2 undergoes budding within the lumen of the endoplasmic reticulum-Golgi intermediate compartment (ERGIC), and the progeny virions are delivered to the cell surface via vesicular transport. However, the molecular mechanisms remain poorly understood. Using three-dimensional electron microscopic analysis, such as array tomography and electron tomography, we found that virion-transporting vesicles possessed protein coats on their membrane and demonstrated that the protein coat was coatomer complex I (COPI). During the later stages of SARS-CoV-2 infection, we observed a notable alteration in the distribution of COPI and ERGIC throughout the cytoplasm, suggesting their potential involvement in virus replication. Depletion of COPB2, a key component of COPI, led to the confinement of SARS-CoV-2 progeny virions within the ERGIC at the perinuclear region. While the expression levels of viral proteins within cells were comparable, this depletion significantly reduced the efficiency of virion release, leading to the significant reduction of viral replication. Hence, our findings suggest COPI as a critical player in facilitating the transport of SARS-CoV-2 progeny virions from the ERGIC. Thus, COPI could be a promising target for the development of antivirals against SARS-CoV-2.
SARS-CoV-2 virions are synthesized within the ERGIC and are transported to the cell surface via vesicular transport for release. However, the precise mechanisms remain unclear. Through various electron microscopic techniques, we identified the presence of COPI on virion-transporting vesicles. Alterations in the distribution of COPI and ERGIC in SARS-CoV-2 infected cells are evident, suggesting their involvement in virus replication. When COPB2, a component of COPI, is depleted, progeny virions become trapped within the ERGIC, leading to a reduction in the efficiency of virion release. These findings highlight COPI's crucial role in mediating SARS-CoV-2 vesicular transport from the ERGIC and suggest it as a potential antiviral target.
严重急性呼吸综合征冠状病毒2（SARS-CoV-2）在内质网-高尔基体中间腔室（ERGIC）的腔内出芽，子代病毒粒子通过囊泡运输被递送至细胞表面。然而，其分子机制仍知之甚少。通过使用三维电子显微镜分析，如阵列断层扫描和电子断层扫描，我们发现病毒粒子运输囊泡在其膜上具有蛋白质衣被，并证明该蛋白质衣被是衣被蛋白复合物I（COPI）。在SARS-CoV-2感染的后期，我们观察到COPI和ERGIC在整个细胞质中的分布有显著改变，表明它们可能参与病毒复制。COPI的关键成分COPB2的缺失导致SARS-CoV-2子代病毒粒子被困在核周区域的ERGIC内。虽然细胞内病毒蛋白的表达水平相当，但这种缺失显著降低了病毒粒子释放的效率，导致病毒复制显著减少。因此，我们的研究结果表明COPI是促进SARS-CoV-2子代病毒粒子从ERGIC运输的关键因素。因此，COPI可能是开发抗SARS-CoV-2抗病毒药物的一个有前景的靶点。
SARS-CoV-2病毒粒子在ERGIC内合成，并通过囊泡运输被转运到细胞表面以释放。然而，确切机制仍不清楚。通过各种电子显微镜技术，我们确定了在病毒粒子运输囊泡上存在COPI。在SARS-CoV-2感染的细胞中，COPI和ERGIC的分布明显改变，表明它们参与病毒复制。当COPI的成分COPB2缺失时，子代病毒粒子被困在ERGIC内，导致病毒粒子释放效率降低。这些发现突出了COPI在介导SARS-CoV-2从ERGIC的囊泡运输中的关键作用，并表明它是一个潜在的抗病毒靶点。
