核仁膜（NE）装配缺陷会导致染色体断裂、癌症和衰老。然而，关于NE装配机制及其与核病理学之间的关系的主要问题仍未解决。特别是，细胞如何从完全不同的细胞类型特异性内质网（ER）形态高效地组装NE尚不清楚。在这里，我们确定了一种NE组装机制，“膜渗透”，它定义了人类细胞中另一种NE组装机制“侧面膜片扩张”的一端。膜浸润涉及通过有丝分裂肌动蛋白丝将ER管或小片段招募到染色质表面。侧面膜片扩张涉及大型ER膜无需肌动蛋白的包裹外周染色质，然后在纺锤体内延伸到染色质上。我们提出了一种“管片连续体”模型，解释了从任何起始ER形态高效NE装配、细胞类型特异性核孔复合物（NPC）装配模式以及“微核”NPC装配缺陷的义务性。版权所有©2023作者。Elsevier Inc.保留所有权利。

Nuclear envelope (NE) assembly defects cause chromosome fragmentation, cancer, and aging. However, major questions about the mechanism of NE assembly and its relationship to nuclear pathology are unresolved. In particular, how cells efficiently assemble the NE starting from vastly different, cell type-specific endoplasmic reticulum (ER) morphologies is unclear. Here, we identify a NE assembly mechanism, "membrane infiltration," that defines one end of a continuum with another NE assembly mechanism, "lateral sheet expansion," in human cells. Membrane infiltration involves the recruitment of ER tubules or small sheets to the chromatin surface by mitotic actin filaments. Lateral sheet expansion involves actin-independent envelopment of peripheral chromatin by large ER sheets that then extend over chromatin within the spindle. We propose a "tubule-sheet continuum" model that explains the efficient NE assembly from any starting ER morphology, the cell type-specific patterns of nuclear pore complex (NPC) assembly, and the obligatory NPC assembly defect of micronuclei.Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.