Bladon T, Brasch K, Brown D L, Setterfield G
Department of Biology, Carleton University, Ottawa, Ont., Canada.
Biochem Cell Biol. 1988 Jan;66(1):40-53. doi: 10.1139/o88-006.
A major component of nuclear change in concanavalin-A-stimulated bovine lymphocytes is a severalfold increase in interchromatinic volume, which coincides with nuclear swelling and extensive structural remodelling. Large-scale ultrastructural changes in isolated nuclei and nuclear matrices (NM) reflect those occurring within nuclei in situ during mitogenesis. While nonchromatinic nuclear material embedded within nuclease- and salt-extracted whole cells closely resembled in situ interchromatinic matrices, large NM isolated in solution shrank after chromatin was extracted. Numerous perinuclear filaments persisted throughout NM isolation and cytoskeletal proteins were identified in two-dimensional (2-D) gels of such preparations. Taken together these data indicated that the lymphocyte cytoskeleton is likely continuous with the nuclear matrix and could play a role in maintaining nuclear organization. A wide range of lymphocyte NM proteins were resolved in 2-D gels. Significant changes in protein composition coincided with nuclear structural remodelling. Lamin B was prominent at each stage of nuclear development, whereas lamins A and C were only found in stimulated lymphocyte matrices. Lymphoblast NM contained more large basic proteins. Progressively increasing polypeptide complexity of these NM arose by de novo protein synthesis and posttranslational modifications throughout concanavalin A stimulation. NM from stimulated lymphocytes also contained more ribonucleoproteins, possibly indicating the presence of significant amounts of transcriptional material.
伴刀豆球蛋白A刺激的牛淋巴细胞中核变化的一个主要成分是染色质间体积增加数倍，这与核肿胀和广泛的结构重塑同时发生。分离的细胞核和核基质（NM）中的大规模超微结构变化反映了有丝分裂发生过程中原位细胞核内发生的变化。虽然核酸酶和盐提取的全细胞中嵌入的非染色质核物质与原位染色质间基质非常相似，但在提取染色质后，溶液中分离出的大型核基质会收缩。在整个核基质分离过程中，许多核周细丝持续存在，并且在此类制剂的二维（2-D）凝胶中鉴定出了细胞骨架蛋白。综合这些数据表明，淋巴细胞细胞骨架可能与核基质连续，并可能在维持核组织中发挥作用。在二维凝胶中解析出了多种淋巴细胞核基质蛋白。蛋白质组成的显著变化与核结构重塑同时发生。核纤层蛋白B在核发育的每个阶段都很突出，而核纤层蛋白A和C仅在受刺激的淋巴细胞基质中发现。成淋巴细胞核基质含有更多的大碱性蛋白。在伴刀豆球蛋白A刺激的整个过程中，这些核基质的多肽复杂性通过从头合成蛋白质和翻译后修饰逐渐增加。来自受刺激淋巴细胞的核基质也含有更多的核糖核蛋白，这可能表明存在大量转录物质。
