Biomaterial Database

Directed transposon Tn5 mutagenesis and complementation analysis of Rhizobium meliloti symbiotic nitrogen fixation genes. 1982

G B Ruvkun, and V Sundaresan, and F M Ausubel

An 18 kb region adjacent to and surrounding the genes for nitrogenase (nif) was cloned from the genome of the symbiotic nitrogen-fixing species Rhizobium meliloti. A total of 31 Tn5 insertions in the nif region were constructed and assayed for their effect on symbiotic nitrogen fixation (Fix phenotype). Fix- insertions were found in two clusters, one 6.3 kb region not containing essential symbiotic genes. The locations of at least three transcription units containing Fix genes were deduced from complementation analysis between genomic nif::Tn5 insertions and nif::Tn5 insertions on mobilizable cloning vectors. The locations of R. meliloti genes nifH, nifD and nifK, which code for the single subunit of the nitrogenase Fe protein and for the two subunits of the nitrogenase MoFe protein respectively, were determined by DNA hybridization to cloned Klebsiella pneumoniae nif genes and by comparison of partial R. meliloti DNA sequences with K. pneumoniae nif gene sequences. R. meliloti nifH, D and K are located in the 6.3 kb fix-::Tn5 cluster and are transcribed in the order nifH, nifD, nifK, which is the same order as in K. pneumoniae.

UI	MeSH Term	Description	Entries
D007711	Klebsiella pneumoniae	Gram-negative, non-motile, capsulated, gas-producing rods found widely in nature and associated with urinary and respiratory infections in humans.	Bacillus pneumoniae,Bacterium pneumoniae crouposae,Hyalococcus pneumoniae,Klebsiella pneumoniae aerogenes,Klebsiella rhinoscleromatis
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D009591	Nitrogenase	An enzyme system that catalyzes the fixing of nitrogen in soil bacteria and blue-green algae (CYANOBACTERIA). EC 1.18.6.1.	Dinitrogenase,Vanadium Nitrogenase,Nitrogenase, Vanadium
D009693	Nucleic Acid Hybridization	Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)	Genomic Hybridization,Acid Hybridization, Nucleic,Acid Hybridizations, Nucleic,Genomic Hybridizations,Hybridization, Genomic,Hybridization, Nucleic Acid,Hybridizations, Genomic,Hybridizations, Nucleic Acid,Nucleic Acid Hybridizations
D010088	Oxidoreductases	The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)	Dehydrogenases,Oxidases,Oxidoreductase,Reductases,Dehydrogenase,Oxidase,Reductase
D003001	Cloning, Molecular	The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.	Molecular Cloning
D004251	DNA Transposable Elements	Discrete segments of DNA which can excise and reintegrate to another site in the genome. Most are inactive, i.e., have not been found to exist outside the integrated state. DNA transposable elements include bacterial IS (insertion sequence) elements, Tn elements, the maize controlling elements Ac and Ds, Drosophila P, gypsy, and pogo elements, the human Tigger elements and the Tc and mariner elements which are found throughout the animal kingdom.	DNA Insertion Elements,DNA Transposons,IS Elements,Insertion Sequence Elements,Tn Elements,Transposable Elements,Elements, Insertion Sequence,Sequence Elements, Insertion,DNA Insertion Element,DNA Transposable Element,DNA Transposon,Element, DNA Insertion,Element, DNA Transposable,Element, IS,Element, Insertion Sequence,Element, Tn,Element, Transposable,Elements, DNA Insertion,Elements, DNA Transposable,Elements, IS,Elements, Tn,Elements, Transposable,IS Element,Insertion Element, DNA,Insertion Elements, DNA,Insertion Sequence Element,Sequence Element, Insertion,Tn Element,Transposable Element,Transposable Element, DNA,Transposable Elements, DNA,Transposon, DNA,Transposons, DNA
D004274	DNA, Recombinant	Biologically active DNA which has been formed by the in vitro joining of segments of DNA from different sources. It includes the recombination joint or edge of a heteroduplex region where two recombining DNA molecules are connected.	Genes, Spliced,Recombinant DNA,Spliced Gene,Recombinant DNA Research,Recombination Joint,DNA Research, Recombinant,Gene, Spliced,Joint, Recombination,Research, Recombinant DNA,Spliced Genes
D005796	Genes	A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.	Cistron,Gene,Genetic Materials,Cistrons,Genetic Material,Material, Genetic,Materials, Genetic
D005816	Genetic Complementation Test	A test used to determine whether or not complementation (compensation in the form of dominance) will occur in a cell with a given mutant phenotype when another mutant genome, encoding the same mutant phenotype, is introduced into that cell.	Allelism Test,Cis Test,Cis-Trans Test,Complementation Test,Trans Test,Allelism Tests,Cis Tests,Cis Trans Test,Cis-Trans Tests,Complementation Test, Genetic,Complementation Tests,Complementation Tests, Genetic,Genetic Complementation Tests,Trans Tests