Disease relevance of galE

• Construction of defined galE mutants of Salmonella for use as vaccines [1].
• The gene, which encodes UDP-galactose 4-epimerase, shows homology to the galE genes of Escherichia coli, Neisseria gonorrhoeae, Rhizobium meliloti, and other gram-negative bacteria [2].
• Bacteriophage U3 was used to isolate galE mutations in HC2142 (a mutant exhibiting reduced response to capR control) [3].
• We suggest that coupling the operon's constitutive promoter to the galE gene fulfills a physiological requirement for constitutive UDPgalactose 4-epimerase expression in Streptomyces [4].
• The promoter region of the rrnB ribosomal RNA gene of Escherichia coli has been ligated within the epimerase gene (galE) of the galactose operon in a lambda phage vector [5].

High impact information on galE

• Our constructions ensured either that there was no upstream translation, or that translation (initiated at the galE ribosome binding site) stopped upstream of, or at the normal position (the T7 gene 1.3 stop codon) with respect to, the transcriptional terminator; or else downstream of both this stop codon and the terminator [6].
• Characterization of two mutations in the Escherichia coli galE gene inactivating the second galactose operator and comparative studies of repressor binding [7].
• This promoter directs transcription of the galT, galE, and galK genes [4].
• The second promoter, galP2, is located within the operon just upstream of the galE gene [4].
• The biological interconversion of galactose and glucose takes place only by way of the Leloir pathway and requires the three enzymes galactokinase, galactose-1-P uridylyltransferase, and UDP-galactose 4-epimerase [8].

Chemical compound and disease context of galE

• The galM protein was homologous to the mutarotase of Acinetobacter calcoaceticus, whereas the galE protein was homologous to UDPglucose 4-epimerase of Escherichia coli and Streptomyces lividans [9].
• Efficient incorporation of galactose into lipopolysaccharide by Escherichia coli K-12 strains with polar galE mutations [10].
• Using hydroxylamine mutagenesis in vitro, mutations were introduced into a short DNA fragment containing the two overlapping promoters of the Escherichia coli galactose operon and the start of the first gal gene, galE [11].
• The resultant phages were allowed to infect to E. coli C (galE), and the lacZ mutant plaques were dominantly selected on a plate containing phenyl-beta-D-galactoside [12].
• A fusion enzyme consisting of UDP-galactose 4-epimerase and galactose-1-P uridylyltransferase with an intervening Ala3 linker was constructed by in-frame fusion of E. coli gene galT to the 3'-terminus of the E. coli gene galE that had been extended with the coding sequence for three alanine residues, all contained within a high-expression plasmid [13].

Biological context of galE

• This galE deletion was recombined into the chromosomal gal operons of S. typhimurium and Salmonella typhi Ty2 [1].
• We constructed a plasmid that contained a defined 0.4-kilobase deletion in the galE but still expressed galT and galK activities from the gal promoter [1].
• Recovery of the wild-type phenotype for the galE mutant was obtained either by genetic complementation or by addition of galactose to the growth medium [14].
• The nucleotide sequence of the galE gene was determined [2].
• P1 transduction was used to cross these mutants with a set of galE gene deletion [3].

Anatomical context of galE

• This symmetry could result in a ribonucleic acid stem-loop structure, blocking the attachment of ribosomes at the Shine-Dalgarno sequence of galE [15].
• Furthermore, infection experiments in vitro indicate that the galE mutants exhibit unaltered intergonococcal adhesion as well as adhesion to, and invasion of, epithelial cells [16].

Associations of galE with chemical compounds

• The resulting strains were vigorous, nonreverting galE mutants that were sensitive to galactose-induced lysis at 0.2 mM galactose [1].
• Subsequently, the galE mutant cells elicited host defense reactions, and they were not stained by fluorescein isothiocyanate-labelled lectin, which efficiently binds to amylovoran capsules of E. amylovora [2].
• We conclude that the absence of a homolog for rfbC precludes the existence of a functional dTDP-rhamnose biosynthesis pathway in the gonococcal strains examined and that these genes are only maintained in N. gonorrhoeae either because of the presence of the galE gene or because of another as yet unrecognized function [17].
• Disruption of the galE gene resulted in poor growth, undetectable intracellular levels of UDP-galactose, and elimination of EPS production in strain NIZO B40 when cells were grown in media with glucose as the sole carbon source [18].
• These galE mutants provided a convenient and specific way to radiolabel lipopolysaccharide [10].

Other interactions of galE

• We describe the molecular cloning of the gal operon of Salmonella typhimurium LT2 and the localization of the gal promoter and the genes galE, galT, and galK [1].
• Cre was provided by the thermosensitive plasmid pJW168, which was transformed into the Anb(R) host at 30 degrees C, and was subsequently eliminated at 42 degrees C. Thus the Anb(R) marker was removed, whereas the lacZ or galE gene remained interrupted by the retained loxP site [19].
• Functional analysis of the Lactococcus lactis galU and galE genes and their impact on sugar nucleotide and exopolysaccharide biosynthesis [18].
• Comparison with sequence databases identified candidate genes for four glycosyl transferases, an O-acetyl transferase, an O-unit flippase, and an O-antigen polymerase, as well as copies of galE and gnd [20].
• The remaining reading frames had homology to galE, rol, and gsk [21].

Analytical, diagnostic and therapeutic context of galE

• Disruption of the galE gene resulted in a deficiency in cell separation along with the appearance of a long-chain phenotype when cells were grown on glucose as the sole carbon source [14].
• Aberrant lipopolysaccharide (LPS) production in the galE mutant Ty21a has resulted in more isoforms of OmpC and subsequently led to anomalous mobility in SDS-PAGE [22].
• A polymerase chain reaction (PCR) protocol was developed that could specifically amplify a 497-bp region of the UDP-galactose 4-epimerase (galE) gene sequence in campylobacters responsible for triggering the onset of GBS [23].
• Neutron activation analysis of UDP-galactose 4-epimerase from Escherichia coli for 53 metals shows that the enzyme does not contain any of these metals at significant levels [24].
• The circular dichroism spectra of E. coli UDP-galactose-4-epimerase in its native (epimerase-NAD+) and reduced (epimerase-NADH.UMP) forms between 190 and 400 nm are presented [25].

References