Dinoflagellate nucleus contains an extensive endomembrane network, the nuclear net
Dinoflagellate nucleus contains an extensive endomembrane network, the nuclear net
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DOI：
10.1038/s41598-018-37065-w
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发表时间：
2019-01-29
影响因子：
4.6
通讯作者：
Leander, Brian S.
中科院分区：
文献类型：
--
作者：
Gavelis, Gregory S.;Herranz, Maria;Leander, Brian S.
甲藻是海洋中最常见的真核细胞之一，但具有非常不寻常的细胞核。许多表现出一种封闭的有丝分裂（二核分裂）形式，其中核膜（NE）内陷形成一个或多个跨核隧道。染色单体不是直接接触纺锤体，而是与 NE 上的膜动粒结合。为了更好地了解这些独特的有丝分裂特征，我们使用聚焦离子束扫描电子显微镜 (FIB-SEM) 结合高压冷冻、冷冻替代、TEM 和共聚焦显微镜以 3D 方式重建了 Polykrikos kofoidii 的核结构。我们发现 P. kofoidii 拥有六个核通道，这些核通道与迄今为止未被注意到的网状膜网络相连。这些膜状延伸将六个隧道互连起来，同时在整个细胞核中分支形成一个“核网”。据我们所知，核网是细胞核内描述的最复杂的内膜结构。我们的研究结果证明了断层扫描方法在检测 3D 膜网络方面的实用性，并表明 Polykrikos kofoidii 以及其他甲藻中的核复杂性被低估了。
Dinoflagellates are some of the most common eukaryotic cells in the ocean, but have very unusual nuclei. Many exhibit a form of closed mitosis (dinomitosis) wherein the nuclear envelope (NE) invaginates to form one or more trans-nuclear tunnels. Rather than contact spindles directly, the chromatids then bind to membrane-based kinetochores on the NE. To better understand these unique mitotic features, we reconstructed the nuclear architecture of Polykrikos kofoidii in 3D using focused ion beam scanning electron microscopy (FIB-SEM) in conjunction with high-pressure freezing, freeze-substitution, TEM, and confocal microscopy. We found that P. kofoidii possessed six nuclear tunnels, which were continuous with a reticulating network of membranes that has thus far gone unnoticed. These membranous extensions interconnect the six tunnels while ramifying throughout the nucleus to form a "nuclear net." To our knowledge, the nuclear net is the most elaborate endomembrane structure described within a nucleus. Our findings demonstrate the utility of tomographic approaches for detecting 3D membrane networks and show that nuclear complexity has been underestimated in Polykrikos kofoidii and, potentially, in other dinoflagellates.