Cytoskeletal distribution and function during the maturation and enucleation of mammalian erythroblasts.
Cytoskeletal distribution and function during the maturation and enucleation of mammalian erythroblasts.
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DOI：
10.1083/jcb.109.6.3005
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发表时间：
1989-12
影响因子：
7.8
通讯作者：
Bondurant, M C
中科院分区：
文献类型：
--
作者：
Koury, S T;Koury, M J;Bondurant, M C
我们使用感染了引起贫血的弗兰德病毒株（FVA细胞）的小鼠脾红细胞作为体外模型来研究红细胞成熟和去核过程中的细胞骨架元素。 FVA 细胞能够在体外悬浮培养物中去核，这表明去核的发生不需要与细胞外基质或辅助细胞的结合。经历去核的 FVA 细胞的形态几乎与体内去核的有红细胞相同。细胞核被分离到细胞的一侧，然后似乎被夹断，导致细胞核和网织红细胞挤出。挤出的细胞核被完整的质膜包围，并且几乎没有与之相关的细胞质。新形成的网织红细胞形状不规则，呈空泡状，包含所有细胞质细胞器。在成熟过程中检查了几种细胞骨架蛋白的空间分布。发现血影蛋白在成熟的所有阶段都与 FVA 细胞的质膜相关，但在去核过程中完全分离到早期的网织红细胞中。微管在未成熟的 FVA 细胞的细胞核周围形成笼子，主要存在于去核细胞的初期网织红细胞中。网织红细胞偶尔含有微管，但微管蛋白的普遍弥散分布更为常见。在FVA细胞成熟过程中的任何时候都无法检测到Vimentin。在最不成熟的成红细胞中，丝状肌动蛋白（F-肌动蛋白）在细胞表面呈斑片状分布，但随着细胞成熟，可以检测到 F-肌动蛋白束。发现 F-肌动蛋白集中在去核红细胞中的挤出核和初期网织红细胞之间。新形成的网织红细胞表现出点状肌动蛋白荧光，而挤出的细胞核缺乏 F-肌动蛋白。向 FVA 细胞培养物中添加秋水仙碱、长春花碱或紫杉醇不会影响去核。相反，细胞松弛素 D 引起去核的完全抑制，可以通过洗掉细胞松弛素 D 来逆转这种抑制。这些结果表明，F-肌动蛋白在去核中发挥作用，而微管完全不存在或聚合微管数量过多并不影响去核。
We have used murine splenic erythrolasts infected with the anemia- inducing strain of Friend virus (FVA cells), as an in vitro model to study cytoskeletal elements during erythroid maturation and enucleation. FVA cells are capable of enucleating in suspension culture in vitro, indicating that associations with an extracellular matrix or accessory cells are not required for enucleation to occur. The morphology of FVA cells undergoing enucleation is nearly identical to erythroblasts enucleating in vivo. The nucleus is segregated to one side of the cell and then appears to be pinched off resulting in an extruded nucleus and reticulocyte. The extruded nucleus is surrounded by an intact plasma membrane and has little cytoplasm associated with it. Newly formed reticulocytes have an irregular shape, are vacuolated and contain all cytoplasmic organelles. The spatial distribution of several cytoskeletal proteins was examined during the maturation process. Spectrin was found associated with the plasma membrane of FVA cells at all stages of maturation but was segregated entirely to the incipient reticulocyte during enucleation. Microtubules formed cages around nuclei in immature FVA cells and were found primarily in the incipient reticulocyte in cells undergoing enucleation. Reticulocytes occasionally contained microtubules, but a generalized diffuse distribution of tubulin was more common. Vimentin could not be detected at any time in FVA cell maturation. Filamentous actin (F-actin) had a patchy distribution at the cell surface in the most immature erythroblasts, but F-actin bundles could be detected as the cells matured. F-actin was found concentrated between the extruding nucleus and incipient reticulocyte in enucleating erythroblasts. Newly formed reticulocytes exhibited punctate actin fluorescence whereas extruded nuclei lacked F-actin. Addition of colchicine, vinblastine, or taxol to cultures of FVA cells did not affect enucleation. In contrast, cytochalasin D caused a complete inhibition of enucleation that could be reversed by washing out the cytochalasin D. These results demonstrate that F-actin plays a role in enucleation while the complete absence of microtubules or excessive numbers of polymerized microtubules do not affect enucleation.