Linked Life Data

1840615

Source:http://linkedlifedata.com/resource/pubmed/id/1840615

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1992-2-11
pubmed:databankReference
pubmed:abstractText
In Rhizobium meliloti, expression of the nodulation genes (nod and nol genes) is under both positive and negative controls. These genes are activated by the products of the three related nodD genes, in conjunction with signal molecules from the host plants. We showed that negative regulation is mediated by a repressor protein, binding to the overlapping nodD1 and nodA as well as to the nodD2 promoters. The encoding gene, termed nolR, was identified and cloned from strain 41. By subcloning, deletion and Tn5 mutagenesis, a region of 594 base-pairs was found to be necessary and sufficient for repressor production in strains of R. meliloti lacking the repressor or in Escherichia coli. Sequence analysis revealed that nolR encodes a 13,349 Da protein, which is in agreement with the molecular weight of the NolR protein, determined after purification by affinity chromatography, utilizing long synthetic DNA multimers of the 21 base-pair conserved repressor-binding sequence. Our data suggest that the native NolR binds to the operator site in dimeric form. The NolR contains a helix-turn-helix motif, which shows homology to the DNA-binding sequences of numerous prokaryotic regulatory proteins such as the repressor XylR or the activator NodD and other members of the LysR family. Comparison of the putative DNA-binding helix-turn-helix motifs of a large number of regulatory proteins pointed to a number of novel regularities in this sequence. Hybridizations with an internal nolR fragment showed that sequences homologous to the nolR gene are present in all R. meliloti isolates tested, even in those that do not produce the repressor. In another species, such as Rhizobium leguminosarum, where NodD is autoregulated, however, such sequences were not detected.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0022-2836
pubmed:author
pubmed:issnType
Print
pubmed:day
20
pubmed:volume
222
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
885-96
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:1840615-Amino Acid Sequence, pubmed-meshheading:1840615-Bacterial Proteins, pubmed-meshheading:1840615-Base Sequence, pubmed-meshheading:1840615-Chromatography, Affinity, pubmed-meshheading:1840615-Chromosome Deletion, pubmed-meshheading:1840615-Cloning, Molecular, pubmed-meshheading:1840615-DNA, Bacterial, pubmed-meshheading:1840615-Escherichia coli, pubmed-meshheading:1840615-Gene Expression Regulation, Bacterial, pubmed-meshheading:1840615-Genes, Bacterial, pubmed-meshheading:1840615-Genes, Regulator, pubmed-meshheading:1840615-Genotype, pubmed-meshheading:1840615-Molecular Sequence Data, pubmed-meshheading:1840615-Mutagenesis, Insertional, pubmed-meshheading:1840615-Nucleic Acid Hybridization, pubmed-meshheading:1840615-Plasmids, pubmed-meshheading:1840615-Promoter Regions, Genetic, pubmed-meshheading:1840615-Recombinant Proteins, pubmed-meshheading:1840615-Repressor Proteins, pubmed-meshheading:1840615-Restriction Mapping, pubmed-meshheading:1840615-Sequence Homology, Nucleic Acid, pubmed-meshheading:1840615-Sinorhizobium meliloti
pubmed:year
1991
pubmed:articleTitle
Identification of NolR, a negative transacting factor controlling the nod regulon in Rhizobium meliloti.
pubmed:affiliation
Centre National de la Recherche Scientifique, Institut des Sciences Végétales, Gif-sur-Yvette, France.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't