IN-VIVO TRANSCRIPTIONAL PAUSING AND CAP FORMATION ON 3 DROSOPHILA HEAT-SHOCK GENES
IN-VIVO TRANSCRIPTIONAL PAUSING AND CAP FORMATION ON 3 DROSOPHILA HEAT-SHOCK GENES
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DOI：
10.1073/pnas.90.17.7923
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发表时间：
1993-09-01
影响因子：
11.1
通讯作者：
LIS, JT
中科院分区：
文献类型：
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作者：
RASMUSSEN, EB;LIS, JT
许多真核基因的调节发生在转录延伸水平上。例如，在黑腹果蝇的未诱导 hsp70 基因上，RNA 聚合酶 II 复合物已启动转录，但在延伸早期暂停。在这项研究中，我们使用顺磁粒子介导的终止连续转录本选择技术，以高分辨率检查了 hsp70 和两个小热休克基因（hsp27 和 hsp26）的暂停。该技术提供了每个转录单元内 RNA 聚合酶分布的精确信息。它还详细介绍了延伸转录本上 5' 帽形成的进展。对于每个基因，我们发现聚合酶暂停在相对较窄的启动子近端区域。这些区域一般约为 20 个核苷酸宽，两个优选的暂停位置间隔大约 10 个核苷酸或大约螺旋一圈。当转录本长度达到 20 到 30 个核苷酸时，就会发生大部分加帽。有趣的是，在这里检查的三个基因中，延伸暂停和 5' 帽形成似乎基本上是一致的。
The regulation of many eukaryotic genes occurs at the level of transcriptional elongation. On the uninduced hsp70 gene of Drosophila melanogaster, for example, an RNA polymerase II complex has initiated transcription but has paused early in elongation. In this study, we examine pausing on hsp70 and two of the small heat shock genes (hsp27 and hsp26) at high resolution, using a technique that utilizes paramagnetic particle-mediated selection of terminated run-on transcripts. This technique provides precise information on the distribution of RNA polymerase within each transcription unit. It also details the progression of 5' cap formation on the elongating transcripts. For each gene, we find polymerases paused over a relatively narrow promoter-proximal region. The regions are generally around 20 nucleotides wide, with two preferred pausing positions spaced roughly 10 nucleotides apart or about one turn of the helix. The bulk of capping occurs as transcripts pass between 20 and 30 nucleotides in length. Interestingly, in the three genes examined here, elongational pausing and 5' cap formation appear largely coincident.