Filser M, Merrick M, Cannon F
Mol Gen Genet. 1983;191(3):485-91. doi: 10.1007/BF00425767.
A total of nine regulatory mutations in the nifLA operon of Klebsiella pneumoniae were cloned in the high copy-number plasmid vector pACYC184. The regulatory phenotypes of the resultant clones were then correlated with their restriction maps and their ability to synthesise nifL and nifA polypeptides in vivo. One mutation, nifL2401, was identified as a 400 bp. deletion within the nifL gene. This mutation was non-polar and caused a Nif+ phenotype which showed escape from repression by oxygen and low levels of fixed nitrogen. Identification of this deletion allows the first definitive allocation of a mutation with this phenotype to the nifL gene and provides further evidence for the role of the nifL gene product in nif-specific repression.
总共九个肺炎克雷伯氏菌nifLA操纵子中的调控突变被克隆到高拷贝数质粒载体pACYC184中。然后将所得克隆的调控表型与其限制酶切图谱以及它们在体内合成nifL和nifA多肽的能力相关联。一个突变，nifL2401，被鉴定为nifL基因内400 bp的缺失。该突变是非极性的，导致Nif+表型，表现出对氧气和低水平固定氮的阻遏逃逸。该缺失的鉴定首次明确地将具有这种表型的突变定位到nifL基因，并为nifL基因产物在nif特异性阻遏中的作用提供了进一步的证据。
