Hormonal regulation of transcription of rDNA: glucocorticoid effects upon initiation and elongation in vitro.
Hormonal regulation of transcription of rDNA: glucocorticoid effects upon initiation and elongation in vitro.
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rDNA 转录的激素调节：糖皮质激素对体外起始和延伸的影响。
DOI：
10.1093/nar/13.9.3357
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发表时间：
1985
影响因子：
14.9
通讯作者：
ThompsonJr,EA
中科院分区：
文献类型：
--
作者：
Cavanaugh,AH;ThompsonJr,EA
使用对照P1798细胞和用0.1 μM地塞米松处理24小时的细胞的提取物，检查了克隆小鼠rDNA转录的各种参数。来自任一来源的高度纯化的RNA聚合酶I以约30个核苷酸/秒的速率催化核苷酸基转移（延伸）。提取物从处理过的细胞能够形成稳定的，preinitiation复合物。稳定复合物形成的速率在来自对照和经酶处理的细胞的提取物中相同。然而，转录的起始并不发生在提取物中从酶处理的细胞。通过加入部分纯化的RNA聚合酶I起始因子（命名为TFIC），可以恢复这些提取物中的起始。数据表明，RNA聚合酶I的起始是一个多步骤的过程。第一步涉及稳定的，preinitiation复合物的形成，证明了一些群体。起始本身需要额外的蛋白质TFIC。糖皮质激素和可能的其他促有丝分裂剂通过影响TFIC的量或活性来调节rDNA的转录。
Various parameters of transcription of cloned mouse rDNA have been examined using extracts from control P1798 cells and from cells treated 24h with 0.1 μM dexamethasone. Highly purified RNA polymerase I from either source catalyzes nucleotidyl transfer (elongation) at a rate of approximately 30 nucleotides/sec. Extracts from hormone-treated cells are capable of forming stable, preinitiation complexes. The rates of stable complex formation are the same in extracts from control and hormone-treated cells. Nevertheless, initiation of transcription does not occur in extracts from hormone-treated cells. Initiation in such extracts may be restored by the addition of a partially purified RNA polymerase I initiation factor, designated TFIC. The data indicate that initiation by RNA polymerase I is a multi-step process. The first step involves the formation of stable, preinitiation complexes, as demonstrated by a number of groups. Initiation,per se, requires an additional protein, TFIC. Glucocorticoids and perhaps other mitogenic agents regulate transcription of rDNA by influencing the amount or activity of TFIC.