Membrane-associated inhibitor of DNA synthesis in senescent human diploid fibroblasts: characterization and comparison to quiescent cell inhibitor.
Membrane-associated inhibitor of DNA synthesis in senescent human diploid fibroblasts: characterization and comparison to quiescent cell inhibitor.
复制标题
衰老人二倍体成纤维细胞中 DNA 合成的膜相关抑制剂：表征以及与静止细胞抑制剂的比较。
DOI：
10.1073/pnas.83.23.9030
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发表时间：
1986
影响因子：
11.1
通讯作者：
Atkins,L
中科院分区：
文献类型：
--
作者：
Stein,GH;Atkins,L
从衰老的人二倍体成纤维细胞（HDF）制备的细胞膜，当加入到复制年轻HDF的培养基中时，抑制进入S期35%。这种膜相关抑制活性（i）对胰蛋白酶、热和高碘酸盐敏感，这表明该抑制剂是一种糖蛋白，（ii）不能抑制猴病毒40转化的HDF中的DNA合成，这表明并非所有类型的细胞均对该抑制剂敏感。静止的年轻HDF也具有DNA合成的表面膜相关抑制剂。衰老HDF和静止HDF抑制剂活性的比较表明，它们可能具有相同的化学和物理性质以及相同的比活性，但它们的调节不同。静止的年轻HDF的抑制活性在用新鲜的含血清培养基再喂养后20小时内被消除，而衰老HDF的抑制活性保持不变。静止的旧HDF（剩余2或3个群体倍增）对血清表现出中等反应，约三分之二的抑制活性消失。刺激后20-24小时处于S期的细胞分数（年轻HDF中为37%，老年HDF中为24%，衰老HDF中为0%）与抑制剂水平成反比。这表明，衰老HDF不能进入S期可能与不能中和血清刺激引起的抑制活性有关。静止期年轻HDF的抑制活性消失发生在G1期晚期。因此，抑制剂可能在确定这些细胞中G 0至S期转变的长度方面发挥作用。
Cell membranes prepared from senescent human diploid fibroblasts (HDF) inhibited entry into S phase by 35% when added to the medium of replicating young HDF. This membrane-associated inhibitory activity was (i) sensitive to trypsin, heat, and periodate, which suggests that the inhibitor is a glycoprotein, and (ii) not able to inhibit DNA synthesis in simian virus 40-transformed HDF, which indicates that not all types of cells are sensitive to this inhibitor. Quiescent young HDF also have a surface membrane-associated inhibitor of DNA synthesis. A comparison of the senescent HDF and quiescent HDF inhibitor activities indicates that they may have the same chemical and physical nature and the same specific activity, but their regulation is different. The inhibitory activity of quiescent young HDF is abolished within 20 hr after refeeding with fresh serum-containing medium, whereas that of senescent HDF remains unchanged. Quiescent old HDF (two or three population doublings remaining) exhibit an intermediate response to serum with approximately two-thirds of the inhibitory activity abolished. The fraction of cells in S phase at 20-24 hr post-stimulation (37% in young HDF, 24% in old HDF, and 0% in senescent HDF) is inversely proportional to inhibitor levels. This suggests that inability to neutralize the inhibitory activity in response to serum stimulation could be involved in the inability of senescent HDF to enter S phase. Disappearance of the inhibitory activity from quiescent young HDF occurs late in G1 phase. Thus, the inhibitor may play a role in determining the length of the G0 to S phase transition in these cells.