首页> 外文期刊>Plasmid: An International Journal Devoted to Extrachromosomal Gene Systems >lambda p(o), a promoter for oop RNA synthesis, has a role in replication of plasmids derived from bacteriophage lambda
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lambda p(o), a promoter for oop RNA synthesis, has a role in replication of plasmids derived from bacteriophage lambda

机译:λp(o),oop RNA合成的启动子,在复制噬菌体λ的质粒中发挥作用

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Transcription initiated at the bacteriophage lambdap(o) promoter gives a short RNA, called oop RNA. Early studies led to a proposal that this transcript plays a role in the initiation of lambda DNA replication. In fact, the p. promoter is located in the lambda replication region and it was suggested that oop RNA may be a primer for replication proceeding leftward from orilambda. However, since in vitro experiments demonstrated that primers for a DNA replication are produced by the dnaG gene product (DnaG primase) and subsequent in vivo studies indicated that oop RNA is an antisense RNA for the lambda cell gene expression, the above-mentioned hypothesis has fallen into oblivion. Nevertheless, here we demonstrate that the p(o) promoter plays a role in lambda DNA replication, indeed. We found that lambda, plasmids bearing a mutation that inactivates po occur in Escherichia coli cells in a copy number significantly lower than wild-type lambda plasmids. Amplification of kpo plasmids during the relaxed response was less efficient relative to kpo plasmids suggesting less frequent initiation of replication from orilambda in the absence of transcription from p(o). This suggestion was confirmed by measurement of incorporation of [H-3]thymidine into lambda plasmid DNA during pulse-labeling experiments. Therefore, we propose that transcription from the p(o) promoter stimulates replication initiation at orilambda as suggested a long time ago, however, contrary to that suggestion, we assume that the process of p(o)-initiated transcription per se but not the transcription product (oop RNA) might play a role at early steps of lambda DNA replication. (C) 2002 Elsevier Science (USA). All rights reserved. [References: 32]
机译:在噬菌体lambdap(o)启动子上启动的转录产生了一个短RNA,称为oop RNA。早期的研究提出了一个建议,即该转录本在λDNA复制的启动中起一定作用。实际上,p。启动子位于λ复制区,提示oop RNA可能是从orilambda向左进行复制的引物。但是,由于体外实验表明由dnaG基因产物(DnaG primase)产生了用于DNA复制的引物,随后的体内研究表明oop RNA是用于lambda细胞基因表达的反义RNA,因此上述假设具有被遗忘。尽管如此,在这里我们证明p(o)启动子确实在λDNA复制中起作用。我们发现,带有使po失活的突变的lambda质粒出现在大肠杆菌细胞中,其拷贝数明显低于野生型lambda质粒。相对于kpo质粒,松弛反应期间kpo质粒的扩增效率较低,这表明在不存在p(o)转录的情况下,从orilambda复制的起始频率较低。通过在脉冲标记实验中测量[H-3]胸苷掺入λ质粒DNA中可以证实这一建议。因此,我们建议从p(o)启动子转录可刺激orilambda的复制起始,正如很久以前所建议的,但是,与该建议相反,我们假设p(o)启动的转录过程本身而不是p(o)启动的过程。转录产物(oop RNA)可能在λDNA复制的早期阶段起作用。 (C)2002 Elsevier Science(美国)。版权所有。 [参考:32]

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