Ewald A, Hofbauer S, Dabauvalle M C, Lourim D
Department of Cell and Developmental Biology, Theodor Boveri Institute, University of Würzburg, Germany.
Eur J Cell Biol. 1997 Jul;73(3):259-69.
Annulate lamellae (AL) are cytoplasmic structures containing pore complexes similar in composition and morphology to nuclear envelope pore complexes. We have tested the ability of Xenopus egg extract to support nuclear membrane and pore complex formation when chromatin is added to extract only after annulate lamellae had been allowed to assemble (preincubated extract). We have observed that preassembly of AL does not inhibit the formation of a double membrane surrounding sperm chromatin. However, these double membranes are often distended, do not support accumulation of karyophilic proteins, and do not possess immunologically or morphologically identifiable pore complexes. We have demonstrated that nuclear pore complex assembly and function can be rescued by adding isolated egg vesicles to the preincubated extract. Our data support the conclusion that multiple vesicle populations are utilized in the formation of a nuclear envelope, including: vesicle population(s) which are common to pore formation in nuclear envelopes and annulate lamellae, and vesicle population(s) which seem to be preferentially utilized for nuclear membrane assembly.
环孔片层（AL）是一种细胞质结构，其包含的孔复合体在组成和形态上与核膜孔复合体相似。我们测试了非洲爪蟾卵提取物在仅在环孔片层组装完成后（预孵育提取物）才向提取物中添加染色质时支持核膜和孔复合体形成的能力。我们观察到，环孔片层的预组装并不抑制围绕精子染色质的双层膜的形成。然而，这些双层膜常常膨胀，不支持亲核蛋白的积累，并且不具有免疫或形态学上可识别的孔复合体。我们已经证明，通过向预孵育提取物中添加分离的卵囊泡，可以挽救核孔复合体的组装和功能。我们的数据支持这样的结论，即多种囊泡群体被用于核膜的形成，包括：在核膜和环孔片层的孔形成中常见的囊泡群体，以及似乎优先用于核膜组装的囊泡群体。
