Merrick M, Filser M, Dixon R, Elmerich C, Sibold L, Houmard J
J Gen Microbiol. 1980 Apr;117(2):509-20. doi: 10.1099/00221287-117-2-509.
The transposons Tn5, Tn7 and Tn10 and bacteriophage Mu have been used to derive insertion mutations in the Klebsiella pneumoniae nif gene cluster. A large number of deletion mutants have been derived by imprecise excision of insertion mutations and these deletions have been used to construct a fine-structure map of the nif cluster. Comparison of this genetic map with a physical map of the nif cluster derived by Reidel et al. (1979) showed a very good correlation between genetic and physical mapping methods. A new complementation group, designated nifU, has been identified and mapped between nifN and nifS. Polarity studies on the 14 nif cistrons now identified suggests that they are organized in at least seven transcriptional units and that all the multicistronic units are transcribed in the same direction.
转座子Tn5、Tn7和Tn10以及噬菌体Mu已被用于在肺炎克雷伯菌固氮基因簇中产生插入突变。通过对插入突变进行不准确切除，已获得大量缺失突变体，这些缺失已被用于构建固氮基因簇的精细结构图。将此遗传图谱与赖德尔等人（1979年）绘制的固氮基因簇物理图谱进行比较，结果表明遗传图谱法和物理图谱法之间具有很好的相关性。现已鉴定出一个新的互补群，命名为nifU，定位于nifN和nifS之间。对目前已确定的14个固氮顺反子进行的极性研究表明，它们至少被组织在7个转录单元中，并且所有多顺反子单元都按相同方向转录。
