Disease relevance of gyrB

• DNA sequence and transcription of the region upstream of the E. coli gyrB gene [1].
• Nucleotide sequence of the Staphylococcus aureus gyrB-gyrA locus encoding the DNA gyrase A and B proteins [2].
• Phage production in one gyrA mutant was severely reduced, but it was only delayed and slightly reduced in other gyrA and gyrB mutants [3].
• The amino acid sequences deduced from gyrA and gyrB displayed 89 and 86% identity, respectively, with the DNA gyrase from Mycobacterium tuberculosis, and 67 and 65% identity, respectively, with that from Streptomyces coelicolor [4].
• High-level fluoroquinolone resistance in a Salmonella typhimurium isolate due to alterations in both gyrA and gyrB genes [5].

High impact information on gyrB

• A parA-containing plasmid localized to similar sites, i.e. close to the poles and at mid-cell, thus indicating that the plasmid co-localizes with ParM [6].
• Thus, our data indicate that parA is a true partitioning system that mediates pairing of plasmids at mid-cell and subsequently moves them to the cell poles before cell division [6].
• Modulation of transcription by DNA supercoiling: a deletion analysis of the Escherichia coli gyrA and gyrB promoters [7].
• We cloned the acrB gene, which has been identified as a mutation of the gyrB gene, and found a double point mutation altering two consecutive amino acids (S759R/R760C) in the COOH-terminal region of the gyrase B subunit [8].
• These results revealed that the acrB mutation is related to the inhibitory mechanism of acriflavine; and the acriflavine sensitivity of the mutant, at least in vitro, is caused mainly by reduction of the enzyme activity [8].

Chemical compound and disease context of gyrB

• Fusions of the Escherichia coli gyrA and gyrB control regions to the galactokinase gene are inducible by coumermycin treatment [9].
• Enoxacin inhibits growth of Escherichia coli K12 strains primarily by binding to the GyrA subunit of DNA gyrase (topoisomerase II); strains with gyrA, but not gyrB, mutations are less susceptible to the bactericidal effects of this agent [10].
• Nalidixic acid-resistant mutations of the gyrB gene of Escherichia coli [11].
• Expression and analysis of two gyrB genes from the novobiocin producer, Streptomyces sphaeroides [12].
• gyrB mutations which confer coumarin resistance also affect DNA supercoiling and ATP hydrolysis by Escherichia coli DNA gyrase [13].

Biological context of gyrB

• By S1 mapping, we have located a transcription start point 31 base pairs upstream of gyrB [1].
• Thus, the organization of the ORFs from ORF44 to ORF638 resembles the organization of genes in the rpmH-gyrB region of the E. coli chromosome [14].
• DNA gyrase on the bacterial chromosome. Oxolinic acid-induced DNA cleavage in the dnaA-gyrB region [15].
• In strains carrying these gyrA or gyrB mutations, pBR322 plasmid DNA exhibited altered levels of supercoiling [3].
• S. aureus recF, gyrB, and gyrA genes are closely spaced, occupy the same reading frame, and may be coordinately expressed [2].

Anatomical context of gyrB

• Immunofluorescence studies using an antibody against parA protein revealed that the subcellular location of parA protein is the nucleus in cultured tobacco mesophyll protoplasts, while conventional GSTs' including the parB product were primarily located in the cytoplasm [16].

Associations of gyrB with chemical compounds

• In quinolone-susceptible cells (top+ gyr+) as well as in topA mutants and in gyrB mutants, plasmid DNA was relaxed after the addition of ciprofloxacin [17].
• This indicates tha mutations in the gyrB gene are responsible for nalidixic acid resistance [11].
• Novobiocin resistance-conferring mutations in S. aureus, H. influenzae, and S. pneumoniae were found in gyrB, and these mutants showed little or no cross-resistance to VRT-125853 or VRT-752586 and vice versa [18].
• In each case, a single point mutation in the gyrB gene converted Arg-133 to Gly or Ile [19].
• In contrast, the only gyrB mutation that conferred a relatively high level of NAL resistance also determined enhanced susceptibility to quinolones with a piperazinyl substituent at C7 position of the quinolone ring (amphoteric quinolones) [20].

Other interactions of gyrB

• At higher osmolarity most compensatory mutations, as expected, are in the gyrA and gyrB genes [21].
• We have determined the sequence of a 1498 base-pair region in E. coli that extends from within dnaN through recF and into the gyrB gene [1].
• The low level of transcription coming to the end of recF, and the highest activity of the gyrB promoter, as well as results obtained with several gyrB::lacZ translational fusions, support the conclusion that gyrB is predominantly expressed from its own promoter under standard growth conditions [22].
• In this paper we describe fusions of both the gyrA and gyrB 5' sequences to the E. coli galactokinase gene [9].
• The relative abundance of 88 proteins was measured in extracts from three strains of Escherichia coli K-12 that are isogenic except for the topA and gyrB genes [23].

Analytical, diagnostic and therapeutic context of gyrB

• We have determined the sequence of the E. coli gyrB gene, using a new sequencing approach in which transposition from a mini-Mu plasmid into the DNA provides random start points for dideoxynucleotide sequence analysis [24].
• Phylogenetic analysis of about 200 strains of Salmonella, Shigella, and Escherichia coli was carried out using the nucleotide sequence of the gene for DNA gyrase B (gyrB), which was determined by directly sequencing PCR fragments [25].
• Confocal laser scanning microscopy of tobacco BY-2 cells showed that the parA product was confined to the nucleus, but was excluded from the nucleolus [16].
• Northern blot analysis revealed that pcpA is expressed during the exponential phase of growth of pneumococci as a monocistronic transcript of about 2.3 kb [26].

References