Nuclear envelope (NE) budding is a recently described phenomenon wherein large macromolecular complexes are packaged inside the nucleus and extruded through the nuclear membranes. Although a general outline of the cellular events occurring during NE budding is now in place, little is yet known about the molecular machinery and mechanisms underlying the physical aspects of NE bud formation. Using a multidisciplinary approach, we identify Wash, its regulatory complex (SHRC), capping protein and Arp2/3 as new molecular components involved in the physical aspects of NE bud formation in a Drosophila model system. Interestingly, Wash affects NE budding in two ways: indirectly through general nuclear lamina disruption via an SHRC-independent interaction with Lamin B leading to inefficient NE bud formation, and directly by blocking NE bud formation along with its SHRC, capping protein and Arp2/3. In addition to NE budding emerging as an important cellular process, it shares many similarities with herpesvirus nuclear egress mechanisms, suggesting new avenues for exploration in both normal and disease biology.

核膜（NE）出芽是最近描述的一种现象，其中大的大分子复合物包装在细胞核内并通过核膜挤出。尽管现在已经有了 NE 出芽过程中发生的细胞事件的总体轮廓，但人们对 NE 芽形成的物理方面的分子机制和机制知之甚少。使用多学科方法，我们将 Wash、其调节复合物 (SHRC)、加帽蛋白和 Arp2/3 确定为参与果蝇模型系统中 NE 芽形成的物理方面的新分子成分。有趣的是，Wash 以两种方式影响 NE 出芽：间接通过一般核纤层破坏，通过与核纤层蛋白 B 的不依赖于 SHRC 的相互作用导致 NE 芽形成效率低下，以及直接通过阻断 NE 芽形成及其 SHRC、加帽蛋白和 Arp2/3 。除了NE出芽作为一个重要的细胞过程而出现之外，它与疱疹病毒核排出机制有许多相似之处，这表明了正常和疾病生物学探索的新途径。