Disease relevance of pyrF

• Nucleotide sequence and characterization of the pyrF operon of Escherichia coli K12 [1].
• Localization of stx, a determinant essential for high-level production of shiga toxin by Shigella dysenteriae serotype 1, near pyrF and generation of stx transposon mutants [2].
• The pyrF gene, encoding OMPdecase, was isolated from a chromosomal library of Pseudomonas aeruginosa PAO1 by screening for complementation of an Escherichia coli and a P. aeruginosa pyrF mutant [3].

High impact information on pyrF

• Active recombinant antibody fragments (Fabs) were selected from a combinatorial cDNA library by complementation of a pyrF strain of Escherichia coli and growth of the library-expressing cells on pyrimidine-free medium [4].
• From a large population of strains of Escherichia coli carrying shear fragments of yeast (Saccharomyces cerevisiae) DNA attached by in vitro recombination to the plasmid vector pMB9, two hybrid plasmids were selected that relieve the pyrimidine requirement of nonreverting pyrF mutants of E. coli [5].
• Inspection of the nucleotide sequence indicates that pyrF gene expression is not regulated by an attenuation control mechanism similar to that described for the pyrBI operon or pyrE gene [1].
• The level of pyrF transcription and OMP decarboxylase synthesis was found to be coordinately derepressed by pyrimidine limitation, indicating that regulation of pyrF gene expression occurs at the transcriptional level [1].
• The pyrF gene of Escherichia coli K12, which encodes the pyrimidine biosynthetic enzyme orotidine-5'-monophosphate (OMP) decarboxylase, is part of an operon that includes a downstream gene designated orfF [1].

Chemical compound and disease context of pyrF

• Stx- mutants of an Stx+ E. coli transductant were generated by random in vivo insertion mutagenesis with a Tn10 derivative transposon, Tn-mini-kan, followed by P1 cotransduction of the kanamycin resistance and PyrF+ markers into a pyrF Stx+ E. coli K-12 recipient [2].

Biological context of pyrF

• The primary transcriptional initiation site is 51 base pairs upstream of the pyrF structural gene [1].
• Complementation of E. coli pyrD, pyrF and pyrE mutants was obtained with a L. plantarum genomic DNA library [6].
• By integrating an F'lac episome into the lac part of the fusions and determining the direction of chromosomal transfer from the resultant Hfr strains, the direction of pyrC transcription was found to be counter-clockwise, while pyrD and pyrF were found to be transcribed in a clockwise direction [7].
• Genetic analysis of these mutants by Hfr conjugation and P1 transduction indicates that the structural gene (rnb) for ribonuclease II is located near the pyrF gene (28 min on the E. coli genetic map of Bachmann, Low and Taylor (1976)), and the most probable gene order is tyrT-trp-pyrF-rnb [8].
• A gene that specifies high-level Shiga toxin production is thus located near pyrF on the chromosome of S. dysenteriae 1 [2].

Associations of pyrF with chemical compounds

• Two of the genes are the well-known pyr genes pyrDb and pyrF, encoding dihydroorotate dehydrogenase and orotidine monophosphate decarboxylase, respectively [9].
• It is linked to pyrF and trp with the order pyrF-trp-gdh [10].
• The mutant strains were deficient in the ability to synthesize either adenine (ade2 and ade5), uracil (ura1, encoding orotidine-5'-phosphate decarboxylase; OMPdecase), tryptophan (trp1, encoding indole-3-glycerol phosphate synthetase; IGPS) or para aminobenzoic acid (pab1) [11].

Other interactions of pyrF

• We have developed an E.coli strain with a non-reverting allele of pyrF that is also suitable for cloning (recA-, hsdR-) [12].
• The Escherichia coli pyrC, pyrD and pyrF genes were cloned on multicopy plasmids derived from pBR322 and analysed by means of restriction endonucleases [7].
• Both ftsZ and pyrF from T. acidophilum were expressed in Escherichia coli and formed functional proteins [13].

Analytical, diagnostic and therapeutic context of pyrF

• The pyrF gene was amplified by polymerase chain reaction, overexpressed in the pT7-7/E. coli BL21(DE3) system and purified to near electrophoretic homogeneity by anion exchange chromatography [3].
• Using blue Sepharose affinity chromatography, we purified orotidine-5'-phosphate decarboxylase over 600-fold, to near homogeneity, from strains of Escherichia coli harboring the cloned pyrF gene on the multicopy plasmid pDK26 [14].

References