The Arabidopsis thaliana glutathione S-transferases zeta class (AtGSTZ) is a multi-functional enzyme, which plays important role in cellular metabolism and environmental purification. Error-prone PCR and cycles of DNA shuffling were used to construct a mutagenesis library of AtGSTZ. The screening of the resultant libraries was carried out by a pH indicator dye-based colorimetric assay. Nine mutants which enhanced the dichloroacetic acid dechlorination activity were obtained. Among them, NN23 contained 25 amino acid substitutions with the activity improving 120%, whereas NN20 contained 24 amino acid substitutions with the activity improving 102%. EC1 contained 2 amino acid substitutions with the activity improving 47%. The rest 6 mutants contained one amino acid substitution with their activity increasing from 9% to 60%. The enzymatic characterization showed that all the evolved enzymes increased their catalytic efficiencies towards dichloroacetic acid and binding affinity towards glutathione whereas some of them increased the renaturability. However there is no obvious change in their thermostability. Based on these data, functional residues related to catalysis and refolding of AtGSTZ were discussed.

Objective To investigate the effects of methylated CpG islands in the promoter region on the expression of killer cell immunoglobulin-like receptor 3DL1 (KIR3DL1).Methods Three voluntary unpaid blood donors carrying high expression allele KIR 3DL1*01502 and three donors carrying low expres-sion allele KIR3DL1*005 were recruited in this study .The nucleotide sequences and the methylated CpG islands in the promoter regions of KIR 3DL1*01502 allele and KIR3DL1*005 allele were analyzed .The NK cells expressing KIR3DL1*01502 and KIR3DL1*005 were respectively treated with 5-aza for the dem-ethylation of CpG islands within the promoters .The expression of KIR3DL1 protein on the surface of NK cells was measured with flow cytometer .Results Two differences at nucleotide sites -65 and -269 were detected within the promoter regions of KIR3DL1*01502 and KIR3DL1*005, resulting in two distinct CpG islands.The CpG islands within the promoter of KIR 3DL1*01502 allele were highly methylated .The ex-pression of KIR3DL1 protein on NK cells which carried KIR 3DL1*01502 allele was significantly increased after the demethylation of CpG islands .However , the treatment of demethylation had no significant effects on the expression KIR3DL1 protein on NK cells harboring KIR3DL1*005 allele.Conclusion The methylated CpG islands within the promoter of KIR 3DL1*01502 allele affected the antigen expression on the surface of NK cells.Different KIR3DL1 alleles might show different mechanisms in regulating antigen expression .

Objective To construct a prokaryotic expression system for major histocompatibility complex class Ⅰ chain-related gene B ( MICB) and to establish an ELISA method for the detection of anti-MICB antibodies in patients with kidney transplantation. Methods The MICB cDNA fragments were ob-tained by RT-PCR with a pair of specific primers. The MICB cDNA and the prokaryotic expression vector pET-28a were digested by two restriction enzymes and ligated to construct the recombinant expression plas-mid pET-28a-MICB. The transformed E. coli BL21 DE3 strains carrying recombinant expression plasmid were induced by IPTG to express MICB protein. The expressed recombinant proteins were identified by Western blot assay and purified by Ni-NTA Spin column. The purified proteins were coupled to ELISA for the detection of anti-MICB antibodies in patients with kidney transplantation. Results Three common MICB fragments contained the exons 2 and 3 were obtained. The recombinant proteins were expressed in E. coli BL21 DE3 strains carrying pET-28a-MICB and successfully purified by the Ni-NTA Spin column. Results of the Western blot assay confirmed that the obtained proteins were the target proteins. The ELISA method was successfully established and used for the detection of anti-MICB antibodies in 24 patients with kidney trans-plantation. The absorbance values indicated that the sensitivities of three recombinant MICB proteins were different. Conclusion The expression system for MICB gene was successfully constructed. The established ELISA for the detection of anti-MICB antibodies would pave the way for further investigation on the correla-tions between MICB protein and transplantation immunity.

OBJECTIVETo establish a polymerase chain reaction sequencing-based typing (PCR SBT) method for HLA-DPB1 exons 2 and 3, and to analyze their polymorphisms.

METHODSBased on the sequences of HLA-DPB1 loci, locus-specific primers were designed and applied to amplify the target sequences encompassing the entire exons 2 and 3 of HLA-DPB1. The amplification products were digested by enzymes and directly sequenced in both directions. The genotype was assigned by Assign 3.5+ SBT software.

RESULTSSpecific target fragment was obtained with the PCR amplification, and good quality electropherogram was derived by direct sequencing. Among 242 individuals from Zhejiang Han population, 18 HLA-DPB1 alleles were detected. Alleles with a frequency of > 0.05 have included DPB1*05:01:01/135:01 (0.4112), DPB1*02:01:02 (0.1901), DPB1*04:01:01 (0.1136) and DPB1*02:02 (0.0620). A novel HLA-DPB1*168:01 allele has also been identified. Nine polymorphism sites were founded in the exon 3 region, which included a new SNP site 517 A>T.

CONCLUSIONThe PCR-SBT method for exons 2 and 3 of HLA-DPB1 is reliable, which allowed detection of polymorphisms in exon 3 of the HLA-DPB1 gene.

Alleles ; Exons ; HLA-DP beta-Chains ; genetics ; Humans ; Polymerase Chain Reaction ; Polymorphism, Genetic

OBJECTIVETo explore the function of a novel nonsense mutation c.1476G>A of ITGB3 gene using an in vitro expression system.

METHODSAn eukaryotic expression vector containing ITGB3 c.1476G>A cDNA was generated by site-directed mutagenesis and transformed into E.coli. Plasmid DNA was extracted and sequenced to confirm the target mutations. Wild-type and mutant recombination plasmids were transfected into Chinese hamster ovarian cancer (CHO) cells by nonliposome method, and the stable expression cells were harvested by G418 screening. The ITGB3 gene mRNA transcription and GPIIIa expression level in CHO cells were detected with real-time quantitative PCR, Western blotting and flow cytometry, respectively.

RESULTSThe eukaryotic expression vectors of wild ITGB3 cDNA and c.1476G>A mutant were successfully constructed. CHO cells with stable expression were obtained after transfection and screening. Compared with the wild-type transfected cells, the amount of CD61 antigen expression was 37% and mRNA transcription level was only 6% in the mutant-transfected cells. Full length GPIIIa protein was found only in the stably wild-type-transfected cells, but not in mutant-transfected cells by Western blotting analysis.

CONCLUSIONThe ITGB3 c.1476G>A mutation can decrease the transcription level and further affect GPIIIa synthesis and CD61 antigen expression.

Animals ; Base Sequence ; Blood Platelets ; cytology ; metabolism ; CHO Cells ; Cloning, Molecular ; Codon, Nonsense ; genetics ; Cricetinae ; Cricetulus ; Humans ; Integrin beta3 ; genetics ; metabolism ; Molecular Sequence Data ; Plasmids ; genetics ; metabolism ; Point Mutation

OBJECTIVETo generate recombinant GPⅢa as an alternative source for HPA-1a antigen and combine it with Luminex xMAP beads for the detection of HPA-1a-specific alloantibody.

METHODSThe full coding region of ITGB3 gene was amplified and ligated with pcDNA3.1. The recombinant plasmid was transfected into CHO cells, and those with stable expression were screened with G418. Expressed protein was identified and coupled with Luminex xMAP beads, which were then reacted with sera samples. Subsequently, phycoerythrin-labeled anti-species IgG antibody was added to the reaction wells and the median fluorescence was determined on a Luminex-100 analyzer.

RESULTSDNA sequencing confirmed that the cloned ITGB3 gene was HPA-1aa. The recombinant GPⅢa was coupled with Luminex xMAP beads. The sensitivity of Luminex beads assay to detect HPA-1a antibody was dilution 1/32 (3.125 U/mL). The Luminex beads assay could specifically identify the HPA-1a antibody from the test sera, and the results were consistent with that of monoclonal antibody-specific immobilization of platelet antigens (MAIPA) technology. Cross-reactivity was not observed with the samples containing HLA, ABO and other HPA antibodies (HPA-3a and HPA-5b). The results illustrated that to detect HPA antibody with Luminex xMAP beads technology is feasible.

CONCLUSIONRecombinant GPⅢa was successfully obtained and used to establish a Luminex technology-based method for the detection of HPA antibodies.

Animals ; Antigens, Human Platelet ; immunology ; Autoantibodies ; immunology ; Base Sequence ; Blotting, Western ; CHO Cells ; Cricetinae ; Cricetulus ; Humans ; Immunoassay ; methods ; Integrin beta3 ; genetics ; immunology ; metabolism ; Microspheres ; Recombinant Proteins ; immunology ; metabolism ; Reproducibility of Results

OBJECTIVETo explore the effect of α -1,2 fucosyltransferase (FUT1) gene 682A> G and 547_552delAG mutations on the expression of FUT1 mRNA and activity of α -1,2 fucosyltransferase.

METHODSRecombinant expression vectors of FUT1 682A> G and FUT1 547_552delAG were constructed and transfected into COS-7 cells for stable expression screening. Expression of FUT1 mRNA was determined using real-time quantitative PCR. The activity of FUT1 was measured with high-performance liquid chromatography.

RESULTSStably transfected COS-7 cells with wild type FUT1, FUT1 682A> G and FUT1 547_552delAG were respectively obtained. The FUT1 mRNA level of transfected cells with 682A> G and 547_552delAG recombination vectors have measured 101.69% and 102.79% compared with that of wild type FUT1 transfected cells. A specific protein band with about 46 kD was confirmed in the 682A> G transfected cell lysates by SDS-PAGE electrophoresis and Western blotting with 6× His Tag antibody. Similar protein was not identified in the 547_552delAG cells lysates. Enzymes activity of FUT1 682A> G has measured 61.01% compared with wild type FUT1 protein, whilst the activity of FUT1 547_557delAG was completely abolished.

CONCLUSIONFUT1 682A> G and 547_552delAG mutations do not affect the transcript efficiency, although various mutations have different impact on the enzyme's activity.

Animals ; Base Sequence ; Blotting, Western ; COS Cells ; Cercopithecus aethiops ; Chromatography, High Pressure Liquid ; DNA Mutational Analysis ; Fucosyltransferases ; genetics ; metabolism ; Humans ; Mutation ; Recombinant Proteins ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVETo develop a method for separating the human leukocyte antigen (HLA)-A, -B and -C haploid using biotinylated probes and streptavidin magnetic beads in order to solve ambiguous HLA genotyping results.

METHODSBased on sequence information of HLA alleles from the IMGT/HLA database, the 5-biotinylated probes were designed. The probe was mixed and extended with corresponding genomic DNA, and incubated with streptavidin magnetic beads, which could form a streptavidin magnetic beads-biotin-probe DNA complex. The unique DNA haploid binding to corresponding probe was isolated after washes and elution. The separated haploid genomic DNA was used as template for HLA-A, -B and -C loci amplification and sequencing analysis.

RESULTSAmong the 12 HLA-A probes, 19 HLA-B probes and 13 HLA-C probes, DNA sequencing has confirmed that 9 HLA-A probes, 9 HLA-B probes and 5 HLA-C probes could successfully separate the haploid from genomic DNA samples.

CONCLUSIONThe developed method for HLA-A, -B and -C haploid separation is reliable, which can solve certain ambiguity and improve the accuracy of HLA genotyping.

Genotype ; HLA-A Antigens ; genetics ; HLA-B Antigens ; genetics ; HLA-C Antigens ; genetics ; Haploidy ; Humans ; Molecular Probe Techniques ; instrumentation ; Polymerase Chain Reaction ; instrumentation ; methods ; Streptavidin ; chemistry

OBJECTIVE: To study the distribution of KIR3DL2 alleles among ethnic Han Chinese from Zhejiang. METHODS: Genomic DNA was extracted by using a magnetic bead method. The full sequence of the KIR3DL2 gene was amplified with four pairs by PCR primers. The coding regions of 208 unrelated ethnic Han Chinese blood donors were analyzed using a BigDye Terminator v3.1 Sequencing Kit. The genotypes were assigned based on the nucleotide polymorphism of the KIR3DL2 gene. RESULTS: Among the 208 samples, 133 were KIR3DL2 heterozygotes and 75 were homozygotes. Forty six KIR3DL2 genotypes were detected. Respectively, 70, 33 and 23 individuals were found to have a KIR3DL2*00201/KIR3DL2*00201, KIR3DL2*00201/KIR3DL2*00701, and KIR3DL2*00201/KIR3DL2*01001 genotype. Twenty-two KIR3DL2 alleles were discovered, and the frequencies of KIR3DL2*00201, KIR3DL2*00701 and KIR3DL2*01001 were 57.45%, 13.46% and 9.13%, respectively. CONCLUSION The distribution of KIR3DL2 alleles among ethnic Han Chinese in Zhejiang has been determined and fits the criteria for genetic polymorphism.
Alleles ; China ; Ethnic Groups ; Gene Frequency ; Humans ; Polymorphism, Genetic ; Receptors, KIR3DL2