Disease relevance of nodC

• E. coli strains, harboring nodA and/or nodB, did not produce Nod metabolites, whereas the strain expressing nodC produced chitooligosaccharides [1].
• We have analysed the metabolites which are produced in vivo and in vitro by Rhizobium strains which express the single nodA, nodB and nodC genes or combinations of the three [2].
• The deduced NodC protein was the longest of the rhizobia except Bradyrhizobium japonicum [3].
• In 1992 a second group reported a failure to find any evidence of functional complementation of various rhizobial nod mutants by Frankia DNA (nodA, nodB and nodC) [4].
• The genetic elements studied were: ISRm3, an insertion element from Sinorhizobium meliloti; pSB 102, a broad host range mer plasmid; the Rhizobium nodC gene (carried on pSym) and plasmid replication origins repCI and repCII [5].

High impact information on nodC

• Both fusions show differences in expression when borne on inc-P vectors as compared to when located on the pSym megaplasmid. nodD expression from vector-borne copies of the nod segment and response of nodC to plant exudate appear to require additional loci on the megaplasmid [6].
• Degenerate primers were designed based upon an alignment of the amino acid sequences of Streptococcus pyogenes HasA, Xenopus laevis DG42, and Rhizobium meliloti NodC [7].
• Intracellular expression of NodC, encoding a chitin synthase, also reduced nod gene expression [8].
• The nodC genes from rhizobia encode an N-acetylglucosaminyl transferase (chitin synthase) involved in the formation of lipo-chito-oligosaccharide Nod factors that initiate root nodule morphogenesis in legume plants [9].
• We propose that this hydrophobic region contains three transmembrane spans, such that the C-terminus of NodC is located in the periplasm [9].

Chemical compound and disease context of nodC

• Inoculation with genistein-induced Bradyrhizobium japonicum strain 532C and USDA3 also increased (45)Ca(2+) uptake; whereas, inoculation with strain Bj-168, a nodC-mutant incapable of producing LCO, did not [10].
• Homology of Rhizobium meliloti NodC to polysaccharide polymerizing enzymes [11].
• ExoN was found to show strong homology to a UDP-glucose pyrophosphorylase from Acetobacter xylinum, whereas ExoO displayed weak homologies to the NodC proteins from R. meliloti and R. loti [12].

Biological context of nodC

• The DNA sequence of this region has been determined and three open reading frames were identified: genes corresponding to these open reading frames have been called nodA, nodB and nodC and are transcribed in that order [13].
• Rhizobial strains isolated from nodules of several host plant genera were sequenced at three loci: symbiotic nodulation genes (nodB and nodC), the chromosomal housekeeping locus glutamine synthetase II (GSII), and a portion of the 16S rRNA gene [14].
• The nodD1 gene product activates expression of the nodABC operon, as measured by a nodC-lacZ fusion or by transcript analysis, in the presence of crude seed or plant wash or the inducer, luteolin [15].
• Nucleotide sequence of Rhizobium loti nodC [16].
• Phylogeny of Sym plasmids of rhizobia by PCR-based sequencing of a nodC segment [17].

Anatomical context of nodC

• In view of biochemical data characterizing NodC as an outer membrane protein with a large extracellular domain, the pattern of immunolabeling on thin sections suggests that NodC is produced on free cytoplasmic ribosomes prior to assembly in the membrane [18].
• Such a model is incompatible with previous reports suggesting that NodC spans both inner and other membranes [9].

Associations of nodC with chemical compounds

• Using translational fusions of lacZ to nodC, nodS, and nodU, the expression of these genes was shown to be inducible by the isoflavone daidzein and depended on transcription from a DNA region farther upstream [19].
• The basic structure of the Nod signal, an acylated oligomer of N-acetylglucosamine, is synthesized through the action of NodA, NodB, and NodC [20].
• Transcription of nodD2 and nodD3 was constitutive. nodC of R. leguminosarum biovar phaseoli was activated by each of the nodD genes of that biovar in the absence of inducers but expression was enhanced in cells grown with bean exudate or the flavonoids genistein or naringenin [21].
• In the chromosomal nodC::lacZ fusion Bj110-573, nodC gene expression was induced by genistein 2.7-fold more in N-starved young cultures than in nonstarved ones [22].
• We show here that one gene, nodC, shows striking similarity to genes encoding proteins known to be involved in polysaccharide synthesis in yeast and bacteria, specifically chitin and cellulose synthases, as well as a protein with unknown function in Xenopus embryos, DG42 [11].

Other interactions of nodC

• The 3' end of nodC overlapped the 5' end of nodS by 71 nucleotides [19].
• We report here that expression of nolX is differentially responsive to a panel of flavonoids, and that the most potent inducers are also the most active inducers of nodC, a conventional, nod box-associated gene [23].

Analytical, diagnostic and therapeutic context of nodC

• Use of nodulation pattern, stress tolerance, nodC gene amplification, RAPD-PCR and RFLP-16S rDNA analysis to discriminate genotypes of Rhizobium leguminosarum biovar viciae [24].
• Using thin-layer chromatography, high-performance liquid chromatography, and mass spectrometry, we show that in this system R. leguminosarum bv. viciae NodC protein directs the synthesis of chitinpentaose, chitintetraose, chitintriose, and two as yet unidentified modified chitin oligosaccharides [25].

References