Specific transcription of mouse ribosomal DNA in a cell-free system that mimics control in vivo.
Specific transcription of mouse ribosomal DNA in a cell-free system that mimics control in vivo.
复制标题
小鼠核糖体 DNA 在模拟体内控制的无细胞系统中的特异性转录。
DOI：
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发表时间：
1981
影响因子：
11.1
通讯作者：
I. Grummt
中科院分区：
文献类型：
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作者：
I. Grummt
来自小鼠的克隆核糖体 DNA (rDNA) 包含 45S pre-rRNA 转录起始位点和 5' 侧翼序列，已被用作体外转录系统的模板。在存在快速生长的艾利希腹水细胞提取物的情况下，RNA 聚合酶 I 在纯化的 rDNA 区域（45S rRNA 的 5' 末端已定位）中特异性启动。这通过对从截短的模板合成的径流转录本的长度进行电泳分析、通过S1核酸酶图谱以及通过体外产物的杂交分析来证明。粗提物促进小鼠 rDNA 忠实转录的能力与细胞的增殖率相关。只有从呈指数增长的小鼠细胞制备的提取物才含有小鼠核糖体基因忠实转录所需的因子。来自非生长或缓慢生长的小鼠细胞的提取物显示出很少的活性。因此，无细胞系统在某种程度上反映了细胞的 rRNA 合成活性，并且对于鉴定和纯化参与 rDNA 特异性读出的各种因子很有价值，并且可能在核糖体基因转录的调节中发挥核心作用。
Cloned ribosomal DNA (rDNA) from mouse, which contains the initiation site of 45S pre-rRNA transcription and 5' flanking sequences, has been used as the template in an in vitro transcription system. In the presence of extracts from rapidly growing Ehrlich ascites cells, RNA polymerase I initiates specifically in that region of purified rDNA where the 5' end of 45S rRNA has been mapped. This is shown by electrophoretic analysis of the length of run-off transcripts synthesized from truncated templates, by S1 nuclease mapping, and by hybridization analysis of the in vitro products. The ability of the crude extracts to promote faithful transcription of mouse rDNA correlates with the proliferation rate of the cells. Only extracts prepared from exponentially growing mouse cells contain the factor(s) required for the faithful transcription of mouse ribosomal genes. Extracts from nongrowing or slowly growing mouse cells show very little activity. Thus, the cell-free system somehow reflects the rRNA synthetic activity of the cell and will prove valuable for the identification and purification of the various factors that are involved in the specific read-out of rDNA and may play a central role in the regulation of transcription of the ribosomal genes.