Disease relevance of gpt

• The membrane-bound protein EIICB(Glc) encoded by the ptsG gene is the major glucose transporter in Escherichia coli [1].
• More than 55 kilobases of chromosomal DNA of Salmonella typhimurium LT2, including the gpt, proA, ataA, and newD genes, were cloned in plasmid vector pULB113 [2].
• After recovery of lambdaEG10 phage, point mutations in the gpt gene and deletions in the red/gam genes are identified by 6-thioguanine and Spi(-) selection, respectively [3].
• In this model, about 10 copies of lambdaEG10 DNA carrying the gpt gene of E. coli and the red/gam genes of lambda phage are integrated per haploid genome of Sprague-Dawley rats at position 4q24-q31 [3].
• Both galK and gpt were thus expressed under the control of vaccinia virus transcriptional units, and the enzymatic activities were measured in the same cell extract with a filter-binding assay [4].

High impact information on gpt

• SgrS, whose expression is induced in response to phosphosugar stress, act on the ptsG mRNA encoding a major glucose transporter, while RyhB, whose expression is induced in response to Fe depletion, acts on several mRNAs encoding Fe-binding proteins [5].
• We conclude that the membrane-targeting property of IICB(Glc) protein rather than the particular nucleotide or amino acid sequence is required for the efficient degradation of ptsG mRNA in response to metabolic stress [6].
• The destabilization of ptsG-crp mRNA was largely eliminated by frameshift mutations in the transmembrane region [6].
• This down-regulation of ptsG is not exerted at the transcriptional level [7].
• Expression of the glucose transporter gene, ptsG, is regulated at the mRNA degradation step in response to glycolytic flux in Escherichia coli [7].

Chemical compound and disease context of gpt

• Thus, the gpt gene is only one of at least two genes responsible for guanine PRTase activity in E. coli [8].
• The mouse cells carry the Escherichia coli xanthine (guanine) phosphoribosyltransferase (gpt) gene in a retroviral shuttle vector integrated into chromosomal DNA in a proviral form [9].
• We describe the mutagenesis of the IRSI-US5 region of the human cytomegalovirus genome, demonstrating the potential of the E. coli guanosine phosphoribosyl transferase (gpt) gene as a selectable marker for insertion and deletion mutagenesis of high passage (AD169, Towne) as well as low passage (Toledo) strains of virus [10].
• One ORF (termed gpt) encoded a protein of 154 amino acids showing significant amino acid sequence similarity to purine phosphoribosyltransferases, such as xanthine-guanine phosphoribosyltransferase of Escherichia coli and human hypoxanthine phosphoribosyltransferase [11].
• Mutagenic specificity of N-methyl-N'-nitro-N-nitrosoguanidine in the gpt gene on a chromosome of Chinese hamster ovary cells and of Escherichia coli cells [12].

Biological context of gpt

• The yeeI mutants exhibited increased generation times during growth on glucose, reduced transport of methyl-alpha-d-glucopyranoside, a substrate of EIICB(Glc), reduced induction of a ptsG-lacZ operon fusion, and reduced catabolite repression in lactose/glucose diauxic growth experiments [1].
• Recombinant MVs expressing the Escherichia coli lacZ gene were constructed in vitro by transfection of MV-infected rabbit cells with a transfer expression vector, and isolated under growth conditions selecting for transient expression of the E. coli gpt gene [13].
• To examine the kinetics of MF, ENU was administered (50 mg/kg/day for 5 successive days) and gpt MFs in the liver were determined 7, 21, 35, and 70 days after the last injection [3].
• To direct the expression of gpt within this vector, a vaccinia virus promoter region was isolated from the HindIII-F fragment of the genome and inserted 5' to gpt coding sequence [4].
• To test the generation of vector viruses, an insertion plasmid was constructed that contains F11L-specific sequences for homologous recombination, the E. coli lacZ and gpt genes as transient selectable marker, and the vaccinia virus early/late promoter P7.5 for transcriptional control of target gene expression [14].

Anatomical context of gpt

• Cell lines that expressed the gpt gene were isolated, and it was found that these cells contained a single integrated copy of the vector in a proviral form [15].
• Cells with spontaneous mutations in the gpt gene were selected as resistant to 6-thioguanine and then were fused with COS cells for recovery of the mutant genes [9].
• When tested by transfection into fibroblasts, no rearrangements were detected and the presence of the barrier initiation codon was sufficient to completely abolish gpt expression in these cells [16].
• Myeloma, hybridoma, and thymoma cell lines have been successfully transfected for the Escherichia coli xanthine-guanine phosphoribosyltransferase gene (gpt) by using the plasmid vector pSV2-gpt [17].
• We have developed a system to study mutations that affect xanthine-guanine phosphoribosyltransferase gene (gpt) expression in hypoxanthine-guanine phosphoribosyltransferase-deficient CHO cells that have been transformed by the plasmid vector pSV2gpt [18].

Associations of gpt with chemical compounds

• Similarly, cells transfected with gpt controlled by the Drosophila 70 000 mol. wt. heat-shock (hsp 70) promoter show regulated guanine incorporation when heat shocked [19].
• Previous studies in this laboratory had generated a large panel of xanthine guanine phosphoribosyl-transferase (EC 2.4.2.22)-negative mutant lines that possess single-base mutations within the gpt coding sequence [20].
• Thioxanthine is toxic for mammalian cells transformed by the dominant selectable marker gpt [21].
• Recombinant viruses containing the gpt insertion were isolated by selection for growth in the presence of mycophenolic acid [22].
• A polyhistidine sequence is available at the 3' end of the cassette to facilitate chromatographic purification of protein. neo and gpt genes were included in some vectors to serve as selectable markers, and the dhfr gene was included in one to achieve gene amplification in mammalian cells [23].

Other interactions of gpt

• The protein fusions were generated by progressively deleting ptsG from its 3' end and ligating the truncated gene to lacZ and 'phoA lacking promoter and leader sequences [24].
• Two other genes, phoE and gpt, which map closely to the proBA genes in E. coli, were also found to be in close proximity to the proBA genes of V. parahaemolyticus [25].

Analytical, diagnostic and therapeutic context of gpt

• The gpt gene was amplified from chromosomal DNA by use of the polymerase chain reaction (PCR), and the amplified DNA sequenced directly by the dideoxy method [26].
• Southern blot hybridization analyses revealed that most XPRT mutant cell lines which arose following treatment with EMS (20/22) or ICR 191 (20/24) exhibited no alterations of the gpt locus detectable by this technique [27].
• Both northern blot and S1 analyses demonstrate that the mutation dramatically accelerates the degradation of ptsG mRNA [7].
• Xanthine phosphoribosyltransferase from Leishmania donovani. Molecular cloning, biochemical characterization, and genetic analysis [28].
• Crystallization and preliminary X-ray crystallographic studies of Escherichia coli xanthine phosphoribosyltransferase [29].

References