Age-related NADH oxidase (arNOX = ENOX3) proteins are superoxide-generating cell surface oxidases that increase in activity with age beginning at about 30 y. A soluble and truncated exfoliated form of the activity is ...Age-related NADH oxidase (arNOX = ENOX3) proteins are superoxide-generating cell surface oxidases that increase in activity with age beginning at about 30 y. A soluble and truncated exfoliated form of the activity is present in blood and other body fluids. The activity was purified to apparent homogeneity from human urine and resolved by 2-D gel electrophoresis into a series of 24 to 32 kDa components of low isoelectric point. The purified proteins were resistant both to N-terminal sequencing and trypsin cleavage. Cleavage with pepsin revealed peptides corresponding to the TM9 family of transmembrane proteins. Peptide antisera raised to all five members of the human TM9 family sequentially blocked the arNOX activity of human saliva and sera. The soluble truncated N-terminus of the human homolog TM9SF4 was expressed in bacteria. The recombinant protein was characterized biochemically and exhibited ar-NOX activity. The findings identify five arNOX isoforms each of which correspond to one of the five known TM9 family members. The exfoliated soluble arNOX forms are derived from the 24 to 32 kDa N-termini exposed to the cell’s exterior at the cell surface. Each of the shed forms contain putative functional motifs characteristic of ECTO-NOX (ENOX) proteins despite only minimal sequence identity. Our findings identify arNOX as having functional characteristics of ENOX proteins and the TM9 superfamily of proteins as the genetic origins of the five known arNOX isoforms present in human sera, plasma and other body fluids1.展开更多
AIM: To develop and optimize cDNA representational difference analysis (cDNA RDA) method and to identify and clone garlic up-regulated genes in human gastric cancer (HGC) cells. METHODS: We performed cDNA RDA method b...AIM: To develop and optimize cDNA representational difference analysis (cDNA RDA) method and to identify and clone garlic up-regulated genes in human gastric cancer (HGC) cells. METHODS: We performed cDNA RDA method by using abundant double-stranded cDNA messages provided by two self-constructed cDNA libraries (Allitridi-treated and paternal HGC cell line BGC823 cells cDNA libraries respectively). Bam H I and Xho I restriction sites harbored in the library vector were used to select representations. Northern and Slot blots analyses were employed to identify the obtained difference products. RESULTS: Fragments released from the cDNA library vector after restriction endonuclease digestion acted as good marker indicating the appropriate digestion degree for library DNA. Two novel expressed sequence tags (ESTs) and a recombinant gene were obtained. Slot blots result showed a 8-fold increase of glia-derived nexin/protease nexin 1 (GDN/PN1) gene expression level and 4-fold increase of hepatitis B virus x-interacting protein (XIP) mRNA level in BGC823 cells after Allitridi treatment for 72h. CONCLUSION: Elevated levels of GDN/PN1 and XIP mRNAs induced by Allitridi provide valuable molecular evidence for elucidating the garlic's efficacies against neurodegenerative and inflammatory diseases. Isolation of a recombinant gene and two novel ESTs further show cDNA RDA based on cDNA libraries to be a powerful method with high specificity and reproducibility in cloning differentially expressed genes.展开更多
AIM: Using bacterial, yeast, or mammalian cell expressing a human drug metabolism enzyme would seem good way to study drug metabolism-related problems. Human cytochrome P-450 2C9(CYP2C9) is a polymorphic enzyme respon...AIM: Using bacterial, yeast, or mammalian cell expressing a human drug metabolism enzyme would seem good way to study drug metabolism-related problems. Human cytochrome P-450 2C9(CYP2C9) is a polymorphic enzyme responsible for the metabolism of a large number of clinically important drugs. It ranks among the most important drug metabolizing enzymes in humans. In order to provide a sufficient amount of the enzyme for drug metabolic research, the CYP2C9 cDNA was cloned and expressed stably in CHL cells. METHODS: After extraction of total RNA from human liver tissue, the human CYP2C9 cDNA was amplified with reverse transcription-polymerase chain reaction (RT-PCR), and cloned into cloning vector pGEM-T. The cDNA fragment was identified by DNA sequencing and subcloned into a mammalian expression vector pREP9. A transgenic cell line was established by transfecting the recombinant vector of pREP9-CYP2C9 into CHL cells. The enzyme activity of CYP2C9 catalyzing oxidation of tolbutamide to hydroxy tolbutamide in S9 fraction of the cell was determined by high performance liquid chromatography(HPLC). RESULTS: The amino acid sequence predicted from the cDNA segment was identical to that of CYP2C9*1, the wild type CYP2C9. However, there were two base differences, i.e. 21T】C, 1146C】T, but the encoding amino acid sequence was the same, L7, P382. The S9 fraction of the established cell line metabolizes tolbutamide to hydroxy tolbutamide; tolbutamide hydroxylase activity was found to be 0.465 +/- 0.109 micromol.min(-1).g(-1) S9 protein or 8.62 +/- 2.02mol.min(-1).mol(-1) CYP, but was undetectable in parental CHL cell. CONCLUSION: The cDNA of human CYP2C9 was successfully cloned and a cell line of CHL- CYP2C9, efficiently expressing the protein of CYP2C9, was established.展开更多
The nucleotide sequence deduced from the amino acid sequence of the scorpion insectotoxin AaIT was chemically synthesized and was expressed in Escherichia coli. The authenticity of this in vitro expressed peptide was ...The nucleotide sequence deduced from the amino acid sequence of the scorpion insectotoxin AaIT was chemically synthesized and was expressed in Escherichia coli. The authenticity of this in vitro expressed peptide was confirmed by N-terminal peptide sequencing. Two groups of bioassays, artificial diet incorporation assay and contact insecticidal effect assay, were carried out separately to verify the toxicity of this recombinant toxin. At the end of a 24 h experimental period, more than 60% of the testing diamondback moth (Plutella xylostella) larvae were killed in both groups with LC50 value of 18.4 microM and 0.70 microM respectively. Cytotoxicity assay using cultured Sf9 insect cells and MCF-7 human cells demonstrated that the toxin AaIT had specific toxicity against insect cells but not human cells. Only 0.13 microM recombinant toxin was needed to kill 50% of cultured insect cells while as much as 1.3 microM toxin had absolutely no effect on human cells. Insect cells produced obvious intrusions from their plasma membrane before broken up. We infer that toxin AaIT bind to a putative sodium channel in these insect cells and open the channel persistently, which would result in Na+ influx and finally cause destruction of insect cells.展开更多
AIM： To establish a simplified method for generating peptide-major histocompatibility complex （MHC） class I tetramers.METHODS： cDNAs encoding the extracellular domain of human lymphocyte antigen （HLA）-A＊0201 he...AIM： To establish a simplified method for generating peptide-major histocompatibility complex （MHC） class I tetramers.METHODS： cDNAs encoding the extracellular domain of human lymphocyte antigen （HLA）-A＊0201 heavy chain （A2） and β2-microglobulin （132m） from total RNA extracted from leukocytes of HLA-A2＋ donors were doned into separate expression vectors by reverse transcription-polymerase chain reaction. The recombinant A2 and 132m proteins were expressed in ~/a oo/i^uain BL21（DE3） and recovered from the inclusion body fraction. Soluble A2 proteins loaded with specific antigen peptides were refolded by dilution from the heavy chain in the presence of light chain 132m and HLA-A2-restricted peptide antigens. The refolded A2 monomers were biotinylated with a commercial biotinylation enzyme （BirA） and purified by low pressure anion exchange chromatography on a Q-Sepharose （fast flow） column.The tetramers were then formed by mixing A2 monomers with streptavidin-PE in a molar ratio of 4：1. Flow cytometry was used to confirm the expected tetramer staining of CD8^＋ T cells.RESULTS： Recombinant genes for HLA-A＊0201 heavy chain （A2） fused to a BirA substrate peptide （A2-BSP） and mature β2m from HLA-A2＋ donor leukocytes were successfully doned and highly expressed in E. coli, Two soluble monomeric A2-peptide complexes were reconstituted from A2-BSP in the presence of 132m and peptides loaded with either human cytomegalovirus pp65495-503 peptide （NLVPMVATV,NLV; designated as A2-NLV） or influenza virus matrix protein Mp58-66 peptide （GILGFVFTL, GIL; designated as A2-GIL）. Refolded A2-NLV or A2-GIL monomers were biotinylated and highly purified by single step anion exchange column chromatography. The tetramers were then formed by mixing the biotinylated A2-NLV or A2-GIL monomers with streptavidin-PE, leading to more than 80% multiplicationas revealed by SDS-PAGE under non-reducing, unboiled conditions. Flow cytometry revealed that these tetramers could specifically bind to CD8^＋ T cells from a HLA-A2^＋ donor,but failed to bind to those from a HLA-A2- donor.CONCLUSION： The procedure is simple and efficient for generating peptide-MHC tetramers.展开更多
OBJECTIVE: To clone the full length of renal cell carcinoma (RCC) related novel gene GYLZ-RCC18 and study its function. METHODS: SMART RACE technology was used to clone the full length of GYLZ-RCC18. RT-PCR was used t...OBJECTIVE: To clone the full length of renal cell carcinoma (RCC) related novel gene GYLZ-RCC18 and study its function. METHODS: SMART RACE technology was used to clone the full length of GYLZ-RCC18. RT-PCR was used to detect its expression in renal cell carcinoma tissue at different stages and grades. We transfected the antisense oligonucleotide of GYLZ-RCC18 to renal cell carcinoma cell line, GRC-1, and analyzed proliferation activity, growth rate, apoptosis, and mortality changes. RESULTS: The full length of GYLZ-RCC18 (GenBank accession number: BE825133) cDNA was about 3.5 kb. GYLZ-RCC18 had a higher expression in higher grades and stages of renal cell carcinoma than in lower ones. The expression of GYLZ-RCC18 in renal cell carcinoma was much higher than in normal kidney. After the transfection of GYLZ-RCC18 antisense oligonucleotide, the mortality of GRC-1 increased significantly, while proliferative activity and growth rate were substantially inhibited at the same time. The antisense oligonucleotide induced apoptosis of GRC-1 through the entire observation time. CONCLUSION: GYLZ-RCC18 is an important novel gene related to renal cell carcinoma. Overexpression of this gene results in higher growth and proliferative activity and has an antiapoptosis effect on renal cell carcinoma cells. Transfection of the antisense oligonucleotide may inhibit the generation and development of renal cell carcinoma.展开更多
文摘Age-related NADH oxidase (arNOX = ENOX3) proteins are superoxide-generating cell surface oxidases that increase in activity with age beginning at about 30 y. A soluble and truncated exfoliated form of the activity is present in blood and other body fluids. The activity was purified to apparent homogeneity from human urine and resolved by 2-D gel electrophoresis into a series of 24 to 32 kDa components of low isoelectric point. The purified proteins were resistant both to N-terminal sequencing and trypsin cleavage. Cleavage with pepsin revealed peptides corresponding to the TM9 family of transmembrane proteins. Peptide antisera raised to all five members of the human TM9 family sequentially blocked the arNOX activity of human saliva and sera. The soluble truncated N-terminus of the human homolog TM9SF4 was expressed in bacteria. The recombinant protein was characterized biochemically and exhibited ar-NOX activity. The findings identify five arNOX isoforms each of which correspond to one of the five known TM9 family members. The exfoliated soluble arNOX forms are derived from the 24 to 32 kDa N-termini exposed to the cell’s exterior at the cell surface. Each of the shed forms contain putative functional motifs characteristic of ECTO-NOX (ENOX) proteins despite only minimal sequence identity. Our findings identify arNOX as having functional characteristics of ENOX proteins and the TM9 superfamily of proteins as the genetic origins of the five known arNOX isoforms present in human sera, plasma and other body fluids1.
基金the Natural Scientific Foundation of China (NSFC3962526)National High-Technology Project-863 (102-10-01-04)
文摘AIM: To develop and optimize cDNA representational difference analysis (cDNA RDA) method and to identify and clone garlic up-regulated genes in human gastric cancer (HGC) cells. METHODS: We performed cDNA RDA method by using abundant double-stranded cDNA messages provided by two self-constructed cDNA libraries (Allitridi-treated and paternal HGC cell line BGC823 cells cDNA libraries respectively). Bam H I and Xho I restriction sites harbored in the library vector were used to select representations. Northern and Slot blots analyses were employed to identify the obtained difference products. RESULTS: Fragments released from the cDNA library vector after restriction endonuclease digestion acted as good marker indicating the appropriate digestion degree for library DNA. Two novel expressed sequence tags (ESTs) and a recombinant gene were obtained. Slot blots result showed a 8-fold increase of glia-derived nexin/protease nexin 1 (GDN/PN1) gene expression level and 4-fold increase of hepatitis B virus x-interacting protein (XIP) mRNA level in BGC823 cells after Allitridi treatment for 72h. CONCLUSION: Elevated levels of GDN/PN1 and XIP mRNAs induced by Allitridi provide valuable molecular evidence for elucidating the garlic's efficacies against neurodegenerative and inflammatory diseases. Isolation of a recombinant gene and two novel ESTs further show cDNA RDA based on cDNA libraries to be a powerful method with high specificity and reproducibility in cloning differentially expressed genes.
基金National Natural Science Foundation of China,No.39770868Natural Science Foundation of Zhejiang Province,No.397490
文摘AIM: Using bacterial, yeast, or mammalian cell expressing a human drug metabolism enzyme would seem good way to study drug metabolism-related problems. Human cytochrome P-450 2C9(CYP2C9) is a polymorphic enzyme responsible for the metabolism of a large number of clinically important drugs. It ranks among the most important drug metabolizing enzymes in humans. In order to provide a sufficient amount of the enzyme for drug metabolic research, the CYP2C9 cDNA was cloned and expressed stably in CHL cells. METHODS: After extraction of total RNA from human liver tissue, the human CYP2C9 cDNA was amplified with reverse transcription-polymerase chain reaction (RT-PCR), and cloned into cloning vector pGEM-T. The cDNA fragment was identified by DNA sequencing and subcloned into a mammalian expression vector pREP9. A transgenic cell line was established by transfecting the recombinant vector of pREP9-CYP2C9 into CHL cells. The enzyme activity of CYP2C9 catalyzing oxidation of tolbutamide to hydroxy tolbutamide in S9 fraction of the cell was determined by high performance liquid chromatography(HPLC). RESULTS: The amino acid sequence predicted from the cDNA segment was identical to that of CYP2C9*1, the wild type CYP2C9. However, there were two base differences, i.e. 21T】C, 1146C】T, but the encoding amino acid sequence was the same, L7, P382. The S9 fraction of the established cell line metabolizes tolbutamide to hydroxy tolbutamide; tolbutamide hydroxylase activity was found to be 0.465 +/- 0.109 micromol.min(-1).g(-1) S9 protein or 8.62 +/- 2.02mol.min(-1).mol(-1) CYP, but was undetectable in parental CHL cell. CONCLUSION: The cDNA of human CYP2C9 was successfully cloned and a cell line of CHL- CYP2C9, efficiently expressing the protein of CYP2C9, was established.
基金This work was supported by a grant from 863High Technology Program,Chinese Ministry of Sci-ence and Technology
文摘The nucleotide sequence deduced from the amino acid sequence of the scorpion insectotoxin AaIT was chemically synthesized and was expressed in Escherichia coli. The authenticity of this in vitro expressed peptide was confirmed by N-terminal peptide sequencing. Two groups of bioassays, artificial diet incorporation assay and contact insecticidal effect assay, were carried out separately to verify the toxicity of this recombinant toxin. At the end of a 24 h experimental period, more than 60% of the testing diamondback moth (Plutella xylostella) larvae were killed in both groups with LC50 value of 18.4 microM and 0.70 microM respectively. Cytotoxicity assay using cultured Sf9 insect cells and MCF-7 human cells demonstrated that the toxin AaIT had specific toxicity against insect cells but not human cells. Only 0.13 microM recombinant toxin was needed to kill 50% of cultured insect cells while as much as 1.3 microM toxin had absolutely no effect on human cells. Insect cells produced obvious intrusions from their plasma membrane before broken up. We infer that toxin AaIT bind to a putative sodium channel in these insect cells and open the channel persistently, which would result in Na+ influx and finally cause destruction of insect cells.
基金Supported by the National Natural Science Foundation of China, No. 30230350 and No. 30371651Major State Basic Research Development Program of China, 973 Program, No. G2000057006
文摘AIM： To establish a simplified method for generating peptide-major histocompatibility complex （MHC） class I tetramers.METHODS： cDNAs encoding the extracellular domain of human lymphocyte antigen （HLA）-A＊0201 heavy chain （A2） and β2-microglobulin （132m） from total RNA extracted from leukocytes of HLA-A2＋ donors were doned into separate expression vectors by reverse transcription-polymerase chain reaction. The recombinant A2 and 132m proteins were expressed in ~/a oo/i^uain BL21（DE3） and recovered from the inclusion body fraction. Soluble A2 proteins loaded with specific antigen peptides were refolded by dilution from the heavy chain in the presence of light chain 132m and HLA-A2-restricted peptide antigens. The refolded A2 monomers were biotinylated with a commercial biotinylation enzyme （BirA） and purified by low pressure anion exchange chromatography on a Q-Sepharose （fast flow） column.The tetramers were then formed by mixing A2 monomers with streptavidin-PE in a molar ratio of 4：1. Flow cytometry was used to confirm the expected tetramer staining of CD8^＋ T cells.RESULTS： Recombinant genes for HLA-A＊0201 heavy chain （A2） fused to a BirA substrate peptide （A2-BSP） and mature β2m from HLA-A2＋ donor leukocytes were successfully doned and highly expressed in E. coli, Two soluble monomeric A2-peptide complexes were reconstituted from A2-BSP in the presence of 132m and peptides loaded with either human cytomegalovirus pp65495-503 peptide （NLVPMVATV,NLV; designated as A2-NLV） or influenza virus matrix protein Mp58-66 peptide （GILGFVFTL, GIL; designated as A2-GIL）. Refolded A2-NLV or A2-GIL monomers were biotinylated and highly purified by single step anion exchange column chromatography. The tetramers were then formed by mixing the biotinylated A2-NLV or A2-GIL monomers with streptavidin-PE, leading to more than 80% multiplicationas revealed by SDS-PAGE under non-reducing, unboiled conditions. Flow cytometry revealed that these tetramers could specifically bind to CD8^＋ T cells from a HLA-A2^＋ donor,but failed to bind to those from a HLA-A2- donor.CONCLUSION： The procedure is simple and efficient for generating peptide-MHC tetramers.
基金ThisprojectwassupportedbyagrantfromtheNationalNaturalScienceFoundationofChina (No 3 9870 841)
文摘OBJECTIVE: To clone the full length of renal cell carcinoma (RCC) related novel gene GYLZ-RCC18 and study its function. METHODS: SMART RACE technology was used to clone the full length of GYLZ-RCC18. RT-PCR was used to detect its expression in renal cell carcinoma tissue at different stages and grades. We transfected the antisense oligonucleotide of GYLZ-RCC18 to renal cell carcinoma cell line, GRC-1, and analyzed proliferation activity, growth rate, apoptosis, and mortality changes. RESULTS: The full length of GYLZ-RCC18 (GenBank accession number: BE825133) cDNA was about 3.5 kb. GYLZ-RCC18 had a higher expression in higher grades and stages of renal cell carcinoma than in lower ones. The expression of GYLZ-RCC18 in renal cell carcinoma was much higher than in normal kidney. After the transfection of GYLZ-RCC18 antisense oligonucleotide, the mortality of GRC-1 increased significantly, while proliferative activity and growth rate were substantially inhibited at the same time. The antisense oligonucleotide induced apoptosis of GRC-1 through the entire observation time. CONCLUSION: GYLZ-RCC18 is an important novel gene related to renal cell carcinoma. Overexpression of this gene results in higher growth and proliferative activity and has an antiapoptosis effect on renal cell carcinoma cells. Transfection of the antisense oligonucleotide may inhibit the generation and development of renal cell carcinoma.
