Setterfield G, Hall R, Bladon T, Little J, Kaplan J G
J Ultrastruct Res. 1983 Mar;82(3):264-82. doi: 10.1016/s0022-5320(83)80014-8.
Nuclei of lymphocytes stimulated in vitro with concanavalin A (Con A) were classified into three morphotypes: I--unstimulated; II--partially stimulated; III--fully stimulated, lymphoblastic nuclei. During the Con A-induced change from morphotype I to III nuclear volume increased up to sixfold, due to a near 10-fold increase in the interchromatinic region. At the same time, condensed chromatin rose in volume by only about 1.5-fold and became disaggregated in to small clumps. Regressive EDTA-uranyl staining demonstrated a large increase in interchromatinic fibrillar material in morphotypes II and III. Nuclear matrices isolated from stimulated murine lymphocytes showed structures comparable to the interchromatinic region of the morphotypes. The Con A-stimulated change in nuclear structure preceded onset of DNA replication and was unaffected by hydroxyurea or cytosine arabinoside. Cycloheximide blocked the structural change, even when given 20 hr after Con A. Autoradiography after [3H]leucine showed incorporation of label in the interchromatinic region of morphotype II and III nuclei, much of which remained stable during a 48-hr chase period. Nuclear structural activation was inhibited by alpha-amanitin but a significant stable nuclear RNA fraction was not detected. We conclude that an important event in lymphocyte activation is extensive synthesis of stable proteinaceous interchromatinic matrix which may be involved in chromatin remodeling and DNA replication and/or transcription.
用刀豆球蛋白A（Con A）体外刺激淋巴细胞的细胞核可分为三种形态类型：I型——未刺激型；II型——部分刺激型；III型——完全刺激型，即淋巴母细胞核。在Con A诱导的从形态类型I到III的转变过程中，核体积增加至六倍，这是由于染色质间区域增加了近10倍。与此同时，凝聚的染色质体积仅增加约1.5倍，并分散成小团块。回归性EDTA-铀染色显示，形态类型II和III的染色质间纤维物质大量增加。从受刺激的小鼠淋巴细胞中分离出的核基质显示出与形态类型的染色质间区域相当的结构。Con A刺激引起的核结构变化先于DNA复制开始，且不受羟基脲或阿糖胞苷的影响。放线菌酮即使在Con A作用20小时后给予也能阻断结构变化。[3H]亮氨酸放射自显影显示，标记物掺入形态类型II和III细胞核的染色质间区域，其中大部分在48小时的追踪期内保持稳定。核结构激活受到α-鹅膏蕈碱的抑制，但未检测到显著的稳定核RNA组分。我们得出结论，淋巴细胞激活中的一个重要事件是稳定的蛋白质性染色质间基质的大量合成，其可能参与染色质重塑以及DNA复制和/或转录。
