ORGANIZATION OF TRANSCRIPTIONAL SIGNALS IN PLASMIDS PBR322 AND PACYC184
ORGANIZATION OF TRANSCRIPTIONAL SIGNALS IN PLASMIDS PBR322 AND PACYC184
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DOI：
10.1073/pnas.78.1.167
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发表时间：
1981-01-01
期刊：
影响因子：
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通讯作者：
BUJARD, H
中科院分区：
文献类型：
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作者：
STUBER, D;BUJARD, H
电子显微镜分析的体外转录复合物的pBR 322和PACYC 184揭示了五个和六个主要的转录单位，分别在这两个质粒载体。这些单位以不同的效率转录，这取决于单个启动子的强度，在pBR 322中差异高达10倍。一个最有趣的信号安排被发现在四环素抗性区的开始，其中两个部分重叠的启动子（P1和P2）启动转录反向。而P2已知促进四环素抗性并被HindIII切割失活，P1能够转录整合在该位点的DNA，并可能有助于pBR 322中β-内酰胺酶基因的表达。在pACYC 184中，除了P1、P2和cat（氯霉素抗性）启动子（P5）之外，两个起始位点（P3和P4）被定位在似乎是插入序列1的一部分的区域中。转录信号的地图允许更可预测地利用这些克隆工具，也允许重新解释早期的克隆结果。
Electron microscopic analysis of in vitro transcriptional complexes of pBR322 and pACYC184 revealed five and six major transcriptional units, respectively, in these two plasmid vectors. These units are transcribed with various efficiencies, depending upon the individual promoter strengths, which differ in pBR322 up to 10-fold. A most interesting signal arrangement was found at the beginning of the tetracycline resistance region, where two partially overlapping promoters (P1 and P2) initiate transcription crosswise in opposite directions. Whereas P2 is known to promote tetracycline resistance and to be inactivated by HindIII cleavage, P1 is able to transcribe DNA integrated at that site and probably contributes to the expression of the beta-lactamase gene in pBR322. In pACYC184, besides P1, P2, and the cat (chloramphenicol resistance) promoter (P5), two initiation sites (P3 and P4) were mapped in a region that appears to be part of insertion sequence 1. The maps of transcription signals permit a more predictable utilization of these cloning vehicles and also allow the reinterpretation of earlier cloning results.