RT Journal Article SR Electronic(1) A1 Merrick, Mike A1 Filser, Mechthild A1 Dixon, Ray A1 Elmerich, Claudine A1 Sibold, Lionel A1 Houmard, JeanYR 1980 T1 The Use of Translocatable Genetic Elements to Construct a Fine-structure Map of the Klebsiella pneumoniae Nitrogen Fixation (nif) Gene Cluster JF Microbiology, VO 117 IS 2 SP 509 OP 520 DO https://doi.org/10.1099/00221287-117-2-509 PB Microbiology Society, SN 1465-2080, AB 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., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-117-2-509