Olins A L, Buendia B, Herrmann H, Lichter P, Olins D E
Foundation for Blood Research, 69 US Route One, Scarborough, Maine, 04070-0190, USA.
Exp Cell Res. 1998 Nov 25;245(1):91-104. doi: 10.1006/excr.1998.4210.
Exposure of the human leukemic cell line (HL-60) to 1 microM retinoic acid (RA) induces in vitro granulopoiesis, including the development of lobulated nuclei. Ultrastructural studies, presented here, demonstrate the formation of extensive quantities of nuclear envelope-limited chromatin sheets (ELCS), in addition to nuclear lobulation, following treatment with RA. ELCS contain DNA, as shown by the Feulgen-like electron microscope stain osmium ammine-B. Lamin B was demonstrated in ELCS by immunoelectron microscopy with colloidal gold-labeled antibody. Formation of ELCS occurred in Bcl2-overexpressing HL-60 cell sublines with suppressed apoptotic cell death, indicating separable mechanisms for ELCS formation and apoptosis. Immunofluorescent and immunoblotting procedures demonstrated modulations in the amounts and distribution of nuclear envelope-associated components. Total amounts of lamins A/C and cytoplasmic vimentin were reduced by RA treatment. The amounts of lamin B, lamin B receptor (LBR), and lamina-associated polypeptide 2 (LAP2) did not exhibit significant quantitative changes, but acquired heterogeneous staining patterns on the nuclear envelope. RA induced the appearance of low-molecular-weight LBR-related proteins. This study demonstrated the parallel induction of lobulated nuclei and of ELCS and the modulation of nuclear envelope components following exposure of HL-60 to retinoic acid.
将人白血病细胞系（HL-60）暴露于1微摩尔视黄酸（RA）可在体外诱导粒细胞生成，包括分叶核的形成。本文所展示的超微结构研究表明，在用RA处理后，除了核分叶外，还形成了大量核膜限制的染色质片层（ELCS）。如用类福尔根电子显微镜染色锇氨-B所示，ELCS含有DNA。通过用胶体金标记抗体的免疫电子显微镜在ELCS中证实了核纤层蛋白B。ELCS的形成发生在过表达Bcl2且凋亡细胞死亡受到抑制的HL-60细胞亚系中，这表明ELCS形成和凋亡的机制是可分离的。免疫荧光和免疫印迹程序证明了核膜相关成分的数量和分布发生了变化。RA处理使核纤层蛋白A/C和细胞质波形蛋白的总量减少。核纤层蛋白B、核纤层蛋白B受体（LBR）和核纤层相关多肽2（LAP2）的数量没有表现出显著的定量变化，但在核膜上获得了异质性染色模式。RA诱导了低分子量LBR相关蛋白的出现。本研究证明了HL-60暴露于视黄酸后分叶核和ELCS的平行诱导以及核膜成分的调节。
