Is the fur gene of Rhizobium leguminosarum essential?
Using primers corresponding to conserved regions of the bacterial regulatory gene fur, a homologue of this gene from the genome of Rhizobium leguminosarum biovar viciae, the nitrogen-fixing symbiont of peas, was isolated and sequenced. The fur gene is normally expressed constitutively, independent of the presence of Fe in the medium, but in one Rhizobium strain it was transcribed at a low level. Attempts to isolate a fur knockout mutant failed, suggesting that the gene is essential for free-living growth. In other bacteria, certain fur mutations confer manganese resistance; however, none of the manganese-resistant mutants of R. leguminosarum which we isolated was corrected by the cloned fur gene. When the cloned R. leguminosarum fur gene was introduced into a fur mutant of Escherichia coli, it caused some Fe-dependent reduction in the amount of siderophore, indicating that it can function heterologously.
de Luca
N G
NG
School of Biological Sciences, University of East Anglia, Norwich, UK.
Wexler
M
M
Pereira
M J
MJ
Yeoman
K H
KH
Johnston
A W
AW
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D004269:DNA, Bacterial / Q000235:genetics; D004352:Drug Resistance, Microbial / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D007501:Iron / Q000378:metabolism; D008345:Manganese / Q000494:pharmacology; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction / Q000379:methods; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D016961:Rhizobium leguminosarum / Q000235:genetics* / Q000254:growth & development; D017422:Sequence Analysis, DNA
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012097:Repressor Proteins; C068477:ferric uptake regulating proteins, bacterial; D008345:Manganese; D007501:Iron