ACTINOMYCIN BINDING PROPERTIES OF STIMULATED HUMAN LYMPHOCYTES
ACTINOMYCIN BINDING PROPERTIES OF STIMULATED HUMAN LYMPHOCYTES
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DOI：
10.1016/0014-4827(69)90032-9
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发表时间：
1969-01-01
影响因子：
3.7
通讯作者：
BOLUND, L
中科院分区：
文献类型：
--
作者：
RINGERTZ, NR;DARZYNKIEWICZ, Z;BOLUND, L
在培养的人淋巴细胞中，只有一小部分细胞能结合标记的放线菌素D（~ 3 H-AMD），并能将~ 3 H-尿苷转化为RNA。向这种培养物中加入植物血凝素（PHA）可显著增加细胞结合3 H-AMD和合成RNA的频率。能结合3 H-AMD的细胞频率与合成RNA的细胞频率之间存在密切的平行关系。在短时间内，RNA合成速率与单个细胞结合的3 H-AMD量之间也存在良好的相关性。然而，在后期阶段，几乎所有的原始细胞都显示出中等的AMD结合，但标记尿苷的掺入非常强。如果在标记后，在没有放线菌素的情况下继续孵育，则细胞中几乎没有3 H-AMD丢失。用未标记的AMD孵育4 h后去除结合的3 H-AMD，对照细胞和PHA刺激的细胞中的3 H-AMD没有明显的丢失，说明结合在活细胞上的AMD的量可能只占DNA中潜在结合位点总数的很小一部分。动力学研究表明，至少有两种不同类型的结合：一种是早期的快速结合，另一种是缓慢的结合。PHA刺激的细胞和对照细胞在快速结合类型方面不同，但在较慢的结合形式方面没有差异。这表明，快速类型的结合反映了多大的一部分染色质可用于转录。
In cultures of human lymphocytes only a small percentage of the cells is capable of binding labelled actinomycin D (3H-AMD), and of incorporating3H-uridine into RNA. Addition of phytohaemagglutinin (PHA) to such cultures markedly increases the frequency of cells binding3H-AMD and of cells synthesizing RNA. There is a close parallelism between the frequency of cells capable of binding3H-AMD and the frequency of cells synthesizing RNA. For a short period of time there is also a good correlation between the rate of RNA synthesis and the amount of3H-AMD bound by individual cells. At later stages, however, practically all blast cells show a moderate AMD-binding, but a very strong incorporation of labelled uridine.Little3H-AMD is lost from the cells if, after the labelling, the incubation is continued in the absence of actinomycin. Attempts to remove bound3H-AMD by postincubation with unlabelled AMD for time periods up to 4 h did not result in any marked loss of3H-AMD from control cells and PHA stimulated cells.It is pointed out that the quantity of AMD bound to living cells probably only represents a very small fraction of the total number of potential binding sites in the DNA. This fraction appears to vary depending on the functional state of the chromatin.Kinetic studies suggest that there are at least two different types of binding: one early and rapid form of binding and a second, slow, form of binding. The PHA-stimulated and the control cells differ with respect to the rapid type of binding but not with respect to the slower form of binding. It is suggested that the rapid type of binding reflects how large a portion of the chromatin is available for transcription.