Glutamate-1-semiadhyde aminotransferase (GSAT) is an enzyme in the upstream biosynthetic pathway of uroporphyrinogen III that is the substrate of uroporphyrinogen III methyltransferase (UPMT), a novel red fluorescent protein. In order to detect the effect of overexpression of GSAT with UPMT on the fluorescent intensity in Escherichia coli, we amplified maize upmt gene by PCR and inserted into the first cistron of pET Duet-1 plasmid to create the vector pETU. The expressed UPMT was fused histidine tag at N terminus. We also amplified E. coli hemL gene encoding GSAT by PCR reaction, eliminated Nco I site within the hemL gene by site-directed mutagenesis and subcloned into pET-51b plasmid. The resultant hemL gene was inserted the second cistron of pETU plasmid to produce the vector pETeGU. The expressed GSAT has the extra Strep-TagII at N terminus. Compared to overexpression upmt gene alone, coexpression both genes did not resulted in the remarkable change in either the amount of the UPMT, as estimated by western blot analysis, or the constitution of red fluorescent materials, as shown by UV/visible light scanning analysis, but increased cellular level of the fluorescent material trimethylpyrrocorphin with the specific absorption at 354 nm. The red fluorescence emitted by the colonies cooverexpressing both enzymes completely disappeared after treated by 2 mmol/L gabaculine, the GSAT inhibitor, suggested that the recombinant GSAT may increase the cellular level of uroporphyrinogen III, and thus enhanced the red fluorescence of the E. coli cells conferred by the recombinant UPMT.
Escherichia coli ; genetics ; metabolism ; Genes, Plant ; Genetic Vectors ; genetics ; Intramolecular Transferases ; biosynthesis ; genetics ; Luminescent Proteins ; biosynthesis ; genetics ; Methyltransferases ; biosynthesis ; genetics ; Mutagenesis, Site-Directed ; Recombinant Proteins ; biosynthesis ; genetics ; Zea mays ; genetics

BACKGROUND: Multidrug-resistant Enterobacteriaceae is a worldwide problem. Although various resistance mechanisms have been recognized with increasing frequency, only a few cases of triple resistance of extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae have been reported. This study was designed to evaluate the coexistence of qnr (qnrA, qnrB, and qnrS) and 16S rRNA methylase (armA, rmtA, rmtB, and rmtC) in ESBL-producing K. pneumoniae. METHODS: We tested 44 isolates of ESBL-producing K. pneumoniae at Chungnam National University Hospital from March to September 2006. Antimicrobial susceptibilities were tested by broth microdilution method, and transconjugation test was performed using E. coli J53 with azide resistance. Search for qnr (qnrA, qnrB, and qnrS) and 16S rRNA methylase (armA, rmtA, rmtB, and rmtC) genes was conducted by PCR amplification, and the genotypes were determined by direct nucleotide sequence analysis of the amplified products. Epidemiologic study was performed by Enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR). RESULTS: All ESBL-positive strains produced qnrB; however, armA was detected in 68.2%. The coproduction rate of qnrB and armA in ESBL-producing K. pneumoniae was 68.2%. Two types (A and B) were dominant in ERIC-PCR results. CONCLUSIONS: K. pneumoniae producing qnrB, armA, and ESBL are spreading widely.
Bacterial Proteins/biosynthesis/*genetics ; Disk Diffusion Antimicrobial Tests ; Drug Resistance, Bacterial/genetics ; Humans ; Klebsiella Infections/microbiology ; Klebsiella pneumoniae/drug effects/*genetics/isolation & purification ; Methyltransferases/biosynthesis/*genetics ; beta-Lactamases/biosynthesis/drug effects/*genetics

Arabidopsis AtPRMT10 is a plant-specific type I protein arginine methyltransferase that can asymmetrically dimethylate arginine 3 of histone H4 with auto-methylation activity. Mutations of AtPRMT10 derepress FLOWERING LOCUS C (FLC) expression resulting in a late-flowering phenotype. Here, to further investigate the biochemical characteristics of AtPRMT10, we analyzed a series of mutated forms of the AtPRMT10 protein. We demonstrate that the conserved "VLD" residues and "double-E loop" are essential for enzymatic activity of AtPRMT10. In addition, we show that Arg54 and Cys259 of AtPRMT10, two residues unreported in animals, are also important for its enzymatic activity. We find that Arg13 of AtPRMT10 is the auto-methylation site. However, substitution of Arg13 to Lys13 does not affect its enzymatic activity. In vivo complementation assays reveal that plants expressing AtPRMT10 with VLD-AAA, E143Q or E152Q mutations retain high levels of FLC expression and fail to rescue the late-flowering phenotype of atprmt10 plants. Taken together, we conclude that the methyltransferase activity of AtPRMT10 is essential for repressing FLC expression and promoting flowering in Arabidopsis.
Arabidopsis ; enzymology ; Arabidopsis Proteins ; biosynthesis ; genetics ; metabolism ; Enzyme Activation ; Flowers ; genetics ; growth & development ; metabolism ; Genetic Loci ; genetics ; MADS Domain Proteins ; biosynthesis ; genetics ; metabolism ; Methyltransferases ; genetics ; metabolism ; Phenotype ; Recombinant Proteins ; genetics ; metabolism ; Time Factors

BACKGROUND: This study was designed to characterize urinary isolates of Escherichia coli that produce extended-spectrum beta-lactamases (ESBLs) and to determine the prevalence of other antimicrobial resistance genes. METHODS: A total of 264 non-duplicate clinical isolates of E. coli were recovered from urine specimens in a tertiary-care hospital in Busan in 2005. Antimicrobial susceptibility was determined by disk diffusion and agar dilution methods, ESBL production was confirmed using the double-disk synergy (DDS) test, and antimicrobial resistance genes were detected by direct sequencing of PCR amplification products. E. coli isolates were classified into four phylogenetic biotypes according to the presence of chuA, yjaA, and TSPE4. RESULTS: DDS testing detected ESBLs in 27 (10.2%) of the 264 isolates. The most common type of ESBL was CTX-M-15 (N=14), followed by CTX-M-3 (N=8) and CTX-M-14 (N=6). All of the ESBL-producing isolates were resistant to ciprofloxacin. PCR experiments detected genes encoding DHA-1 and CMY-10 AmpC beta-lactamases in one and two isolates, respectively. Also isolated were 5 isolates harboring 16S rRNA methylases, 2 isolates harboring Qnr, and 19 isolates harboring AAC(6')-Ib-cr. Most ESBL-producing isolates clustered within phylogenetic groups B2 (N=14) and D (N=7). CONCLUSION: CTX-M enzymes were the dominant type of ESBLs in urinary isolates of E. coli, and ESBL-producing isolates frequently contained other antimicrobial resistance genes. More than half of the urinary E. coli isolates harboring CTX-M enzymes were within the phylogenetic group B2.
Bacterial Proteins/biosynthesis/*genetics ; Bacteriuria/microbiology ; Ciprofloxacin/pharmacology ; Disk Diffusion Antimicrobial Tests ; Drug Resistance, Multiple, Bacterial/*genetics ; Escherichia coli/*drug effects/enzymology/isolation & purification ; Humans ; Methyltransferases/genetics ; Phylogeny ; beta-Lactamases/biosynthesis/*genetics

The study was purposed to investigate the effect of arsenic trioxide (As(2)O(3))- induced p16 gene demethylation by a sensitive and specific PCR-based method (nested-methylation specific PCR, n-MSP) and DNA sequencing for rapid analysis of the promoter demethylation status, and to explore the possible mechanism of the p16 gene demethylation in human multiple myeloma U266 cells induced by As(2)O(3). The methylation status of the p16 gene in U266 cell line before and after treatment with As(2)O(3) was detected by the nested-methylation specific PCR and DNA sequencing, the mRNA of p16, DNA methyltransferase (DNMT 1, DNMT3A and 3B) gene were determined by RT-PCR, and the induced growth inhibition of U266 cell was assayed by growth curve, MTT and CFU; the DNA content of U266 cells was analyzed by flow cytometry after being exposed to As(2)O(3). The results showed that (1) all cytosines in CpG dinucleotides in untreated U266 cell not were changed, while all cytosines in treated U266 cells with As(2)O(3) had been converted to thymidine. (2) p16 gene was not expressed in U266 cell line after methylation. As compared with the beta-actin, the expression of U266 cell p16 gene mRNA was increased to (0.22 +/- 0.10), (0.59 +/- 0.11), (0.68 +/- 0.09) after exposed to 0.5 micromol/L, 1.0 micromol/L and 2.0 micromol/L As(2)O(3) for 72 hours respectively. (3) As(2)O(3) could significantly down-regulate DNA methyltransferase 1 (DNMT 1), DNMT3A and DNMT3B gene at mRNA level in a dose-dependent manner. (4) U266 cells line grew slowly and arrested at G(0) - G(1) phase after treatment with three different concentrations of As(2)O(3). It is concluded that As(2)O(3) can activate and up-regulate the expression of p16 gene which inhibits the proliferation of U266 cell through inducing the G(0) - G(1) arrest by demethylation or/and by inhibiting DNMT 1, DNMT3A and 3B gene.
Antineoplastic Agents ; pharmacology ; Arsenicals ; pharmacology ; Base Sequence ; Cell Line, Tumor ; Cyclin-Dependent Kinase Inhibitor p16 ; biosynthesis ; genetics ; DNA (Cytosine-5-)-Methyltransferase 1 ; DNA (Cytosine-5-)-Methyltransferases ; biosynthesis ; genetics ; DNA Methylation ; drug effects ; Genes, p16 ; Humans ; Molecular Sequence Data ; Multiple Myeloma ; genetics ; metabolism ; pathology ; Oxides ; pharmacology ; Polymerase Chain Reaction ; methods ; Promoter Regions, Genetic ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Transcription, Genetic ; drug effects

To investigate the relationship between the expression of DNMT and clinical prognosis in adult patients with acute leukemia (AL), the mRNA expressions of DNMT, p15(INK4B), mdr1 were measured in 72 AL patients and 20 normal controls by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR); the ratio of p15 CpG land methylation was measured in 56 AL patients and 14 normal controls by methylation-specific PCR (MSP-PCR). The results showed that all three DNMT mRNA expressions in AL patients were significantly higher than that in normal controls (P < 0.01). When the internal control was changed into PCNA, a kind of cell proliferation marker gene, the difference still showed a statistic significance. All three DNMT genes were significantly expressed and positively correlated with AL patients, showing high synergistic expression, and there was a negative correlation between the levels of p15, mdr1 gene expression and DNMT. The complete remission (CR) rate in AL patients with the positive expression of all DNMT genes was significantly higher than that of AL patients with partially positive or negative expression (P < 0.01) of DNMT genes. In 56 AL patients, the P15I(NK4B) was completely methylated in 55.4% (31 of 56), partly methylated in 21.4% (12 of 56) and all 14 cases of normal controls were not methylated. It is concluded that DNMT genes are abnormally high expressed in adult AL patients, which lead to methylation-silence of tumor suppressor genes by CpG land hypermethylation, the AL patients with high expression of DNMT are more sensitive to chemotherapy, which may be a good prognostic factor for AL patients.
ATP Binding Cassette Transporter, Sub-Family B ; ATP-Binding Cassette, Sub-Family B, Member 1 ; genetics ; Acute Disease ; Adult ; Cyclin-Dependent Kinase Inhibitor p15 ; genetics ; DNA (Cytosine-5-)-Methyltransferase 1 ; DNA (Cytosine-5-)-Methyltransferases ; biosynthesis ; genetics ; Female ; Gene Expression Regulation, Leukemic ; Humans ; Leukemia ; genetics ; pathology ; Male ; Prognosis ; Proliferating Cell Nuclear Antigen ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Reverse Transcriptase Polymerase Chain Reaction

BACKGROUND: Members of the Acinetobacter calcoaceticus-baumannii (Acb) complex are important opportunistic bacterial pathogens and present significant therapeutic challenges in the treatment of nosocomial infections. In the present study, we investigated the integrons and various genes involved in resistance to carbapenems, aminoglycosides, and fluoroquinolones in 56 imipenem-nonsusceptible Acb complex isolates. METHODS: This study included 44 imipenem-nonsusceptible A. baumannii, 10 Acinetobacter genomic species 3, and 2 Acinetobacter genomic species 13TU strains isolated in Daejeon, Korea. The minimum inhibitory concentrations (MICs) were determined by Etest. PCR and DNA sequencing were used to identify the genes that potentially contribute to each resistance phenotype. RESULTS: All A. baumannii isolates harbored the blaOXA-51-like gene, and 21 isolates (47.7%) co-produced OXA-23. However, isolates of Acinetobacter genomic species 3 and 13TU only contained blaIMP-1 or blaVIM-2. Most Acb complex isolates (94.6%) harbored class 1 integrons, armA, and/or aminoglycoside-modifying enzymes (AMEs). Of particular note was the fact that armA and aph(3')-Ia were only detected in A. baumannii isolates, which were highly resistant to amikacin (MIC50> or =256) and gentamicin (MIC50> or =1,024). In all 44 A. baumannii isolates, resistance to fluoroquinolones was conferred by sense mutations in the gyrA and parC. However, sense mutations in parC were not found in Acinetobacter genomic species 3 or 13TU isolates. CONCLUSIONS: Several differences in carbapenem, aminoglycoside, and fluoroquinolone resistance gene content were detected among Acb complex isolates. However, most Acb complex isolates (87.5%) possessed integrons, carbapenemases, AMEs, and mutations in gyrA. The co-occurrence of several resistance determinants may present a significant threat.
Acinetobacter Infections/microbiology ; Acinetobacter baumannii/*genetics/isolation & purification ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; DNA Gyrase/genetics ; DNA, Bacterial/chemistry/genetics ; Drug Resistance, Bacterial/*genetics ; Humans ; Imipenem/*pharmacology ; Integrons/genetics ; Methyltransferases/genetics ; Microbial Sensitivity Tests ; Mutation ; Polymerase Chain Reaction ; Republic of Korea ; Sequence Analysis, DNA ; beta-Lactamases/biosynthesis/genetics

OBJECTIVEThis study was designed to clarify the significance of DNA methylation in the expression of runt-related transcription factor 3 (Runx3) gene.

METHODSReverse transcription-PCR (RT-PCR) was used to measure the expression level of Runx3 mRNA in paired samples of primary gastric cancer and corresponding non-cancerous gastric mucosa, taken from surgical specimens of 70 gastric cancer patients. Western blot was used to detect the protein expression level of Runx3 gene. The promoter methylation status of Runx3 gene was detected by methylation specific PCR (MSP). Furthermore, RT-PCR was used to mesure the expression of DNA methyltransferase 1 (Dnmtl) mRNA . The correlation of Runx3 expression and methylation with Dnmt1 mRNA expression was analyzed.

RESULTSThe mRNA expression level of Runx3 gene was significantly lower in gastric cancer than that in the matched normal gastric mucosa (0.5740 +/- 0.3580 vs. 1.7250 +/- 0.4080, P < 0.05), and the Runx3 protein expression level in gastric cancer was also significantly lower than that in the matched normal gastric mucosa (P < 0.05). Promoter hypermethylation of Runx3 gene was detected in 50.0% (28/56) of the gastric cancer samples, which resulted in a reduced expression of Runx3 mRNA. It was found that the mRNA expression level of Dnmt1 gene was significantly higher in the gastric cancer tissues with methylated Runx3 gene than that in the ones without. There was a significant correlation of Runx3 gene methylation with increased expression of Dnmtl mRNA (r = 0.64, P < 0.05).

CONCLUSIONThe promoter hypermethylation may be one of the predominant inactivation mechanisms of the runt-related transcription factor 3 gene, and may be associated with carcinogenesis of human gastric cancer. Reduced Runx3 expression in gastric cancer may be partially correlated with a high level of DNA methyltransferase 1.

Adenocarcinoma ; genetics ; metabolism ; Adult ; Aged ; Core Binding Factor Alpha 3 Subunit ; genetics ; metabolism ; DNA (Cytosine-5-)-Methyltransferase 1 ; DNA (Cytosine-5-)-Methyltransferases ; biosynthesis ; genetics ; DNA Methylation ; Down-Regulation ; Female ; Gene Expression Regulation, Neoplastic ; Humans ; Male ; Middle Aged ; Promoter Regions, Genetic ; RNA, Messenger ; metabolism ; Stomach Neoplasms ; genetics ; metabolism ; Young Adult