CONTROL OF TRANSCRIPTION TERMINATION IN E. COLI

大肠杆菌噬菌体 lambda 染色体上的转录终止被抑制 由病毒N蛋白。 阻断 N 作用的宿主突变（nus、groN） 也影响细菌染色体上的转录终止。 我们发现 nusB 突变体在转录核糖体 RNA 方面存在缺陷；我们是 选择具有此缺陷的其他大肠杆菌突变体。 我们设计了一个 新颖的 lambda 向量来执行此选择，并验证 这些突变体的转录终止受到影响。 其他改变转录终止的大肠杆菌突变已被 被分离为 nusAl 表型的抑制子。 一种这样的抑制器 似乎位于基因“u”中，该基因编码 21 kd 蛋白质，位于 参与 mRNA 翻译的一组基因。 我们希望确定 “u”产品的性质，并询问它是否充当之间的联系 转录和翻译。 λ 噬菌体不会在噬菌体溶原性大肠杆菌上繁殖 HK022。 这种排除是由于 HK022 前噬菌体功能 Nun 发挥作用 作为新的转录终止因子。 Nun 与 Nus 因子相互作用 引发 lambda 螺母位点的过早终止。

Transcription termination on the coliphage lambda chromosome is suppressed by the viral N protein. Host mutations which block N action (nus, groN) also affect transcription termination on the bacterial chromosome. We find that nusB mutants are defective in transcribing ribosomal RNA; we are selecting additional E. coli mutants with this defect. We have designed a novel lambda vector to perform this selection, and to verify that transcription termination is affected in these mutants. Other E. coli mutations that alter transcription termination have been isolated as suppressors of the nusAl phenotype. One such suppressor appears to lie in gene "u", which encodes a 21 kd protein and is located in a cluster of genes involved in mRNA translation. We wish to determine the nature of the "u" product, and to ask if it serves as a link between transcription and translation. Bacteriophage lambda does not propagate on E. coli lysogenic for phage HK022. This exclusion is due to a HK022 prophage function, Nun, which acts as a new transcription termination factor. Nun interacts with Nus factors to provoke premature termination at the lambda nut sites.