We have identified 14 S _locus glycoprotein (SLG)_related protein kinase genes in a 323 kb contig of rice (Oryza sativa L.) chromosome 4 and we detected the transcription pattern of this gene cluster by reverse tra...We have identified 14 S _locus glycoprotein (SLG)_related protein kinase genes in a 323 kb contig of rice (Oryza sativa L.) chromosome 4 and we detected the transcription pattern of this gene cluster by reverse transcription_polymerase reaction (RT_PCR). RT_PCR results revealed that nine putative genes were transcribed in rice and these genes had the different expression patterns: two genes are expressed predominantly in reproductive tissues while the other seven genes are expressed in both reproductive and vegetative tissues. Analysis of the predicted amino acid sequences demonstrated that the extracellular receptor domains are highly homologous to SLG of Brassica, whereas the cytoplasmic kinase domains contain conserved amino acids present in serine/threonine kinases.展开更多
AIM: To investigate the biological function of complete S protein and to look for proteins interacting with complete S protein in hepatocytes. METHODS: We constructed bait plasmid expressing complete S protein of HBV ...AIM: To investigate the biological function of complete S protein and to look for proteins interacting with complete S protein in hepatocytes. METHODS: We constructed bait plasmid expressing complete S protein of HBV by cloning the gene of complete S protein into pGBKT7, then the recombinant plasmid DNA was transformed into yeast AH109 (a type). The transformed yeast AH109 was mated with yeast Y187 (α type) containing liver cDNA library plasmid in 2×YPDA medium. Diploid yeast was plated on synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) containing X-α-gal for selection and screening. After extracting and sequencing of plasmids from positive (blue) colonies, we underwent sequence analysis by bioinformatics. RESULTS: Nineteen colonies were selected and sequenced. Among them, five colonies were Homo sapiens solute carrier family 25, member 23 (SLC25A23), one was Homo sapiens calrer.iculin, one was human serum albumin (ALB) gene, one was Homo sapiens metallothionein 2A, two were Homo sapiens betaine-homocysteine methyltransferase, three were Homo sapiens Na+ and H+coupled amino acid transport system N, one was Homo sapiens CD81 antigen (target of anti-proliferative antibody 1) (CD81), three were Homo sapiens diazepam binding inhibitor, two colonies were new genes with unknown function. CONCLUSION: The yeast-two hybrid system is an effective method for identifying hepatocyte proteins interacting with complete S protein of HBV. The complete S protein may bind to different proteins i.e., its multiple functions in vivo.展开更多
AIM: To investigate the transactivating effect of complete S protein of hepatitis B virus (HBV) and to construct a subtractive cDNA library of genes transactivated by complete S protein of HBV by suppression subtracti...AIM: To investigate the transactivating effect of complete S protein of hepatitis B virus (HBV) and to construct a subtractive cDNA library of genes transactivated by complete S protein of HBV by suppression subtractive hybridization (SSH) technique and to clone genes associated with its transactivation activity, and to pave the way for elucidating the pathogenesis of hepatitis B virus infection. METHODS: pcDNA3.1(-)-complete S containing full-length HBV S gene was constructed by insertion of HBV complete S gene into BamH I/Kpn I sites. HepG2 cells were cotransfected with pcDNA3.1(-)-complete S and pSV-lacZ. After 48 h, cells were collected and detected for the expression of β-galactosidase (β-gal). Suppression subtractive hybridization and bioinformatics techniques were used. The mRNA of HepG2 cells transfected with pcDNA3.Incomplete S and pcDNA3.1(-) empty vector was isolated, and detected for the expression of complete S protein by reverse transcription polymerase chain reaction (RT-PCR) method, and cDNA was synthesized. After digestion with restriction enzyme RsaI, cDNA fragments were obtained. Tester cDNA was then divided into two groups and ligated to the specific adaptors 1 and 2, respectively. After tester cDNA had been hybridized with driver cDNA twice and underwent nested PCR twice, amplified cDNA fragments were subcloned into pGEM-Teasy vectors to set up the subtractive library. Amplification of the library was carried out within E. coli strain DH5α. The cDNA was sequenced and analyzed in GenBank with BLAST search after polymerase chain reaction (PCR) amplification. RESULTS: The complete S mRNA could be detected by RT-PCR in HepG2 cells transfected with the pcDNA3.1(-)-complete S. The activity of β-gal in HepG2 cells transfected with the pcDNA3.1(-)-complete s was 6.9 times higher than that of control plasmid. The subtractive library of genes transactivated by HBV complete S protein was constructed successfully. The amplified library contains 86 positive clones. Colony PCR showed that 86 clones contained DNA inserts of 200-1 000 bp, respectively. Sequence analysis was performed in 35 clones randomly, and the full length sequences were obtained with bioinformatics method and searched for homologous DNA sequence from GenBank, altogether 33 coding sequences were obtained. These cDNA sequences might be target genes transactivated by complete S protein of HBV. Moreover, two unknown genes were discovered, full length coding sequences were obtained by bioinformatics techniques, one of them was named complete S transactivated protein 1 (CSTP1) and registered in GenBank (AY553877). CONCLUSION: The complete S gene of HBV has a transactivating effect on SV40 early promoter. A subtractive cDNA library of genes transactivated by HBV complete S protein using SSH technique has been constructed successfully. The obtained sequences may be target genes transactivated by HBV complete S protein among which some genes coding proteins are involved in cell cycle regulation, metabolism, immunity, signal transduction, cell apoptosis and formation mechanism of hepatic carcinoma.展开更多
The present study aims to define the role of postsynaptic density (PSD)-95 in the regulation of dopamine (DA) receptor function. We found that PSD-95 physically associates with either D1 or D2 DA receptors in co-t...The present study aims to define the role of postsynaptic density (PSD)-95 in the regulation of dopamine (DA) receptor function. We found that PSD-95 physically associates with either D1 or D2 DA receptors in co-transfected HEK-293 cells. Stimulation of DA receptors altered the association between D1 receptor and PSD-95 in a time-depen- dent manner. Functional assays indicated that PSD-95 co-expression did not affect DI receptor-stimulated cAMP pro- duction, Gs-protein activation or receptor desensitization. However, PSD-95 accelerated the recovery of internalized membrane receptors by promoting receptor recycling, thus resulting in enhanced resensitization of internalized D1 receptors. Our results provide a novel mechanism for regulating DA receptor recycling that may play an important role in postsynaptic DA functional modulation and synaptic neuroplasticity.展开更多
Objective: To investigate the time course of serum S-100 concentrations of patients with acute cerebral infarction,and their relation with the clinical data and the prognosis. Methods: Serum S-100 levels were serially...Objective: To investigate the time course of serum S-100 concentrations of patients with acute cerebral infarction,and their relation with the clinical data and the prognosis. Methods: Serum S-100 levels were serially determined in 36 patients with acute cerebral infarction within 12 h, at 24 h and day 2, 3, 4, 5, 7 and 10 after acute cerebral infarction and in 20 age- and sex-matched control subjects. An S-100 content assay was performed using a two-site radioimmunoassay technique. The clinical status was assessed using NIH Stroke Scale. The functional deficit at 4 weeks after acute cerebral infarction was scored using the modified Rankin scale. A cranial computed tomography was performed initially. Results: Elevated concentrations of S-100 (>0.2 μg/L) were observed in 29 of 36 patients with acute cerebral infarction,but none of the control subjects. The S-100 peak levels were at day 2 and 3 after acute cerebral infarction and were significantly high in those patients with severe neurological deficit at admission, with extensive infarction or with space-occupying effect of ischemic edema as compared with the rest of the populations. Conclusion: Serum S-100 level assay can be used as a peripheral marker of ischemic brain damage, and may be helpful for evaluation of therapeutic effects in acute ischemic stroke.展开更多
AIM: To express the complete PreS region of HBV in E.coli with good solubility and stability, and to establish an effective method for purification of the recombinant PreS protein. METHODS: The complete PreS region (P...AIM: To express the complete PreS region of HBV in E.coli with good solubility and stability, and to establish an effective method for purification of the recombinant PreS protein. METHODS: The complete PreS region (PreS1 and PreS2) was fused into a series of tags including glutathione S-transferase (GST), dihydrofolate reductase (DHFR), maltose binding protein (MBP), 6× histidine, chitin binding domain (CBD), and thioredoxin, respectively. Expression of recombinant PreS fusion proteins was examined by SDS-PAGE analysis and confirmed by Western blot. Two fusion proteins, thio-PreS, and PreS-CBD, with desirable solubility and stability, were subjected to affinity purification and further characterization. RESULTS: Recombinant PreS fusion proteins could be synthesized with good yields in E.coli. However, most of these proteins except for thio-PreS and PreS-CBD were vulnerable to degradation or insoluble as revealed by SDS-PAGE and Western blot. Thio-PreS could be purified by affinity chromatography with nickel-chelating sepharose as the matrix. However, some impurities were also co-purified. A simple freeze-thaw treatment yielded most of the thio-PreS proteins in solution while the impurities were in the precipitate. Purified thio-PreS protein was capable of inhibiting the binding of HBV virion to a specific monoclonal antibody against an epitope within the PreS1 domain. CONCLUSION: Increased solubility and stability of the complete PreS region synthesized in E.coli can be achieved by fusion with the thioredoxin or the CBD tag. A simple yet highly effective method has been established for the purification of the thio-PreS protein. Purified thio-PreS protein likely assumes a native conformation, which makes it an ideal candidate for studying the structure of the PreS region as well as for screening antivirals.展开更多
Objective: To study the anti-angiogenesis effect of melittin on human hepatoma Mock/MHCC97-H cells by regulatingthe expression of cathepsin S (CatS) in vivo. Methods: Models of in situ transplantation tumor of Moc...Objective: To study the anti-angiogenesis effect of melittin on human hepatoma Mock/MHCC97-H cells by regulatingthe expression of cathepsin S (CatS) in vivo. Methods: Models of in situ transplantation tumor of Mock/MHCC97-Hcells and silencing cathepsin shRNA-CatS/ MHCC97-H cells in nude mice were established. The model mice wererandomly divided into four groups. In the A1 group, the mice were inoculated with shRNA-CatS/MHCC97-H cells andtreated with melittin. In the A2 group, the mice were inoculated with shRNA-CatS/MHCC97-H cells and treated withsaline. In the B1 group, the mice were inoculated with Mock/MHCC97-H cells and treated with melittin. In the B2 group,the mice were inoculated with Mock/MHCC97-H cells and treated with saline. The A1 and B1 group were injected withmelittin (80 mg/kg) intraperitoneally every day. The A2 and B2 group were injected with 0.2 mL normal salineintraperitoneally every day. After administration for 25 days, the animals were sacrificed. The tumor size and weight innude mice in each group were recorded. The expression of CD34 protein in the xenograft tumor tissues was detected byimmunohistochemistry. The expression of Cat S, VEGF-A, p-VEGFR2, Ras, Raf, p-Raf, MEK1, p-MEK1, ERK1/2 andp-ERK1/2 proteins were detected by western blot. Results: The B1 group had significantly smaller tumor volumes andlower tumor weights than the B2 group (both P 〈 0.001). There was no significant difference between the A1 group andA2 group in tumor volumes and weights. The number of CD34-positive microvessels in the B2 group was significantlyhigher than that in the A2 group (P 〈 0.001). The number of CD34-positive microvessels in the B1 group wassignificantly lesser than that in the A1 group (P 〈 0.001). Most strikingly, in the model featuring inoculation ofMock/MHCC97-H cells, CatS, VEGF-A, p-VEGFR2, Ras, Raf, p-Raf, MEK1, p-MEK1, ERK1/2 and p-ERK1/2expression were inhibited when treated with melittin. However, in the model featuring the inoculation ofshRNA-CatS/MHCC97-H cells, no such effects were observed with similar treatments. Conclusion: Melittin can inhibitthe growth of tumors and angiogenesis by blocking the CatS-VEGf-A signaling pathway.展开更多
Objective To elucidate the effect of interleukin-1β (IL- 1β) on human growth hormone (hGH) gene expression in a rat somatotropic pituitary cell line MtT/S. Methods Stably transfected MtT/S cells were firstly es...Objective To elucidate the effect of interleukin-1β (IL- 1β) on human growth hormone (hGH) gene expression in a rat somatotropic pituitary cell line MtT/S. Methods Stably transfected MtT/S cells were firstly established by transfecting 484-Lucl plasmid which contained hGH gene promoter --484 to +30 bp and luciferase reporter gene. The effect of IL-1β on hGH gene expression was determined by assaying the luciferase activities. RT-PCR method was also used to determine whether IL-1 recepor mRNA was expressed in MtT/S cells. Results The 10^3 U/mL IL-1β stimulated secretion and synthesis of GH, and promoted the 5'-promoter activity of GH gene in stably transfected MtT/SGL cells with the action of 1.38 times above the control. Among inhibitors of signaling transduction pathways, mitogen-activated protein kinase kinase (MAPKK/MEK) inhibitor PD98059 (40 μmol/L) and p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 (5 μmol/L) completely blocked the stimulatory effect of IL-1μ, and phosphatidylinositol-3-kinase (PI3-K) inhibitor LY294002 partly abolished the effect of IL-1μ. Western blot analysis further confirmed the activation of phosphorylated MEK and p38 MAPK in MtT/SGL cells. Neither over-expression of Pit- 1 nor inhibition of Pit- 1 expression affected induction of hGH promoter activity by IL-1μ. A series of deletion constructs of hGH promoter were created to identify the DNA sequence that mediated the effect of IL-1β, and results showed that the stimulatory effect of IL-1β was abolished following deletion of the --196 to -- 132 bp fragment. Conclusions IL-1β promotes GH secretion and synthesis in rat MtT/S somatotroph cells. The stimulatory effect of IL-1β on hGH gene promoter appears to require the activation of MEK, p38 MAPK, PI3-K, and a fragment of promoter sequence that spans the -196 to -132 bp of the gene, but it may be unlinked with Pit-1 protein.展开更多
Adjuvant chemotherapy by S-1 following gastrectomy is considered standard treatment in Japan.Analysis of follow-up data have proved the effi cacy of S-1 admin-istration,and that hematological adverse events were relat...Adjuvant chemotherapy by S-1 following gastrectomy is considered standard treatment in Japan.Analysis of follow-up data have proved the effi cacy of S-1 admin-istration,and that hematological adverse events were relatively rare.Pyrimidine anti-metabolites,including S-1,have shown relatively lower risks for secondary hematological malignancies in comparison to alkylat-ing agents and topoisomerase-Ⅱ inhibitors.We here report a case of therapy-related leukemia after S-1 administration.A patient who had received S-1as the sole adjuvant chemotherapy was diagnosed with acute erythroid leukemia.To the best of our knowledge,our patient represents the fi rst report of S-1 induced acute leukemia.展开更多
Objective Primary malignant melanomas of the liver are exceedingly rare.Only 19 cases have been reported in the literature worldwide.In this report,we describe our pathological findings and review the literature in or...Objective Primary malignant melanomas of the liver are exceedingly rare.Only 19 cases have been reported in the literature worldwide.In this report,we describe our pathological findings and review the literature in order to improve our understanding of the disease and prevent misdiagnosis,as well as provide evidence for its treatment and prognosis.Methods We present a case of an isolated malignant melanoma of the liver in a 61-year-old male Chinese patient.Results Comprehensive dermatological and ophthalmological examinations did not reveal any evidence of a primary cutaneous or ocular lesion.Similarly,serial physical examinations,auxiliary examinations,and bone scans did not demonstrate any other lesions in the brain,respiratory tract,and gastrointestinal tract.Microscopic examination of the resected specimen revealed malignant melanoma,which was confirmed by immunohistochemical staining for S-100 protein(+),ki67(30%+),EMA(+),CD10(+),and HMB-45(++).Conclusion Primary malignant melanoma may occur in the liver,and should be considered when the histopathological appearance is atypical of other hepatic neoplasms.The diagnostic criteria for hepatic malignant melanoma depend mainly on the clinical,radiographic,and histopathological findings.Pathomorphology and immumohistochemical staining can be utilized to confirm the diagnosis.展开更多
文摘We have identified 14 S _locus glycoprotein (SLG)_related protein kinase genes in a 323 kb contig of rice (Oryza sativa L.) chromosome 4 and we detected the transcription pattern of this gene cluster by reverse transcription_polymerase reaction (RT_PCR). RT_PCR results revealed that nine putative genes were transcribed in rice and these genes had the different expression patterns: two genes are expressed predominantly in reproductive tissues while the other seven genes are expressed in both reproductive and vegetative tissues. Analysis of the predicted amino acid sequences demonstrated that the extracellular receptor domains are highly homologous to SLG of Brassica, whereas the cytoplasmic kinase domains contain conserved amino acids present in serine/threonine kinases.
基金Supported by the National Natural Science Foundation of China, No. C03011402, No. C30070690the Science and Technique Foundation of PLA during the 9th Five-year plan period, No. 98D063 the Launching Foundation for Students Studying Abroad of PLA, No. 98H038 the Youth Science and Technique Foundation of PLA during the 10lh Five-year plan period, No. 01Q138and the Science & Technique Foundation of PLA during the 10th Five-year plan period, No. 01MB135
文摘AIM: To investigate the biological function of complete S protein and to look for proteins interacting with complete S protein in hepatocytes. METHODS: We constructed bait plasmid expressing complete S protein of HBV by cloning the gene of complete S protein into pGBKT7, then the recombinant plasmid DNA was transformed into yeast AH109 (a type). The transformed yeast AH109 was mated with yeast Y187 (α type) containing liver cDNA library plasmid in 2×YPDA medium. Diploid yeast was plated on synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) containing X-α-gal for selection and screening. After extracting and sequencing of plasmids from positive (blue) colonies, we underwent sequence analysis by bioinformatics. RESULTS: Nineteen colonies were selected and sequenced. Among them, five colonies were Homo sapiens solute carrier family 25, member 23 (SLC25A23), one was Homo sapiens calrer.iculin, one was human serum albumin (ALB) gene, one was Homo sapiens metallothionein 2A, two were Homo sapiens betaine-homocysteine methyltransferase, three were Homo sapiens Na+ and H+coupled amino acid transport system N, one was Homo sapiens CD81 antigen (target of anti-proliferative antibody 1) (CD81), three were Homo sapiens diazepam binding inhibitor, two colonies were new genes with unknown function. CONCLUSION: The yeast-two hybrid system is an effective method for identifying hepatocyte proteins interacting with complete S protein of HBV. The complete S protein may bind to different proteins i.e., its multiple functions in vivo.
基金Supported by the National Natural Science Foundation of China, No. C03011402, No. C30070690 the Science and Technique Foundation of PLA during the 9th Five-year Plan period, No. 98D063the Launching Foundation for Students Studying Abroad of PLA, No. 98H038the Youth Science and Technique Foundation of PLA during the 10th Five-year plan period, No. 01Q138the Science and Technique Foundation of PLA during the 10th Five-year Plan period, No. 01MB135
文摘AIM: To investigate the transactivating effect of complete S protein of hepatitis B virus (HBV) and to construct a subtractive cDNA library of genes transactivated by complete S protein of HBV by suppression subtractive hybridization (SSH) technique and to clone genes associated with its transactivation activity, and to pave the way for elucidating the pathogenesis of hepatitis B virus infection. METHODS: pcDNA3.1(-)-complete S containing full-length HBV S gene was constructed by insertion of HBV complete S gene into BamH I/Kpn I sites. HepG2 cells were cotransfected with pcDNA3.1(-)-complete S and pSV-lacZ. After 48 h, cells were collected and detected for the expression of β-galactosidase (β-gal). Suppression subtractive hybridization and bioinformatics techniques were used. The mRNA of HepG2 cells transfected with pcDNA3.Incomplete S and pcDNA3.1(-) empty vector was isolated, and detected for the expression of complete S protein by reverse transcription polymerase chain reaction (RT-PCR) method, and cDNA was synthesized. After digestion with restriction enzyme RsaI, cDNA fragments were obtained. Tester cDNA was then divided into two groups and ligated to the specific adaptors 1 and 2, respectively. After tester cDNA had been hybridized with driver cDNA twice and underwent nested PCR twice, amplified cDNA fragments were subcloned into pGEM-Teasy vectors to set up the subtractive library. Amplification of the library was carried out within E. coli strain DH5α. The cDNA was sequenced and analyzed in GenBank with BLAST search after polymerase chain reaction (PCR) amplification. RESULTS: The complete S mRNA could be detected by RT-PCR in HepG2 cells transfected with the pcDNA3.1(-)-complete S. The activity of β-gal in HepG2 cells transfected with the pcDNA3.1(-)-complete s was 6.9 times higher than that of control plasmid. The subtractive library of genes transactivated by HBV complete S protein was constructed successfully. The amplified library contains 86 positive clones. Colony PCR showed that 86 clones contained DNA inserts of 200-1 000 bp, respectively. Sequence analysis was performed in 35 clones randomly, and the full length sequences were obtained with bioinformatics method and searched for homologous DNA sequence from GenBank, altogether 33 coding sequences were obtained. These cDNA sequences might be target genes transactivated by complete S protein of HBV. Moreover, two unknown genes were discovered, full length coding sequences were obtained by bioinformatics techniques, one of them was named complete S transactivated protein 1 (CSTP1) and registered in GenBank (AY553877). CONCLUSION: The complete S gene of HBV has a transactivating effect on SV40 early promoter. A subtractive cDNA library of genes transactivated by HBV complete S protein using SSH technique has been constructed successfully. The obtained sequences may be target genes transactivated by HBV complete S protein among which some genes coding proteins are involved in cell cycle regulation, metabolism, immunity, signal transduction, cell apoptosis and formation mechanism of hepatic carcinoma.
基金Acknowledgments We thank Dr Morgan Sheng (Harvard University, USA) for providing the cDNA construct for PSD-95. This study was sup- ported by the Natural Science Foundation of China (30770662, 30825042) Hi-Tech Research and Development Program of China (2007AA02Z163), National Basic Research Program (2009CB2200) to XZ, and funding from the National Institutes of Health (REY016754A) and the American Heart Association (0665201Y) to JZ. Part of this work was conducted in a facility constructed with support from Research Facilities Improvement Program Grant C06-RR-12088-01 from the National Center for Research Resources.
文摘The present study aims to define the role of postsynaptic density (PSD)-95 in the regulation of dopamine (DA) receptor function. We found that PSD-95 physically associates with either D1 or D2 DA receptors in co-transfected HEK-293 cells. Stimulation of DA receptors altered the association between D1 receptor and PSD-95 in a time-depen- dent manner. Functional assays indicated that PSD-95 co-expression did not affect DI receptor-stimulated cAMP pro- duction, Gs-protein activation or receptor desensitization. However, PSD-95 accelerated the recovery of internalized membrane receptors by promoting receptor recycling, thus resulting in enhanced resensitization of internalized D1 receptors. Our results provide a novel mechanism for regulating DA receptor recycling that may play an important role in postsynaptic DA functional modulation and synaptic neuroplasticity.
文摘Objective: To investigate the time course of serum S-100 concentrations of patients with acute cerebral infarction,and their relation with the clinical data and the prognosis. Methods: Serum S-100 levels were serially determined in 36 patients with acute cerebral infarction within 12 h, at 24 h and day 2, 3, 4, 5, 7 and 10 after acute cerebral infarction and in 20 age- and sex-matched control subjects. An S-100 content assay was performed using a two-site radioimmunoassay technique. The clinical status was assessed using NIH Stroke Scale. The functional deficit at 4 weeks after acute cerebral infarction was scored using the modified Rankin scale. A cranial computed tomography was performed initially. Results: Elevated concentrations of S-100 (>0.2 μg/L) were observed in 29 of 36 patients with acute cerebral infarction,but none of the control subjects. The S-100 peak levels were at day 2 and 3 after acute cerebral infarction and were significantly high in those patients with severe neurological deficit at admission, with extensive infarction or with space-occupying effect of ischemic edema as compared with the rest of the populations. Conclusion: Serum S-100 level assay can be used as a peripheral marker of ischemic brain damage, and may be helpful for evaluation of therapeutic effects in acute ischemic stroke.
基金Supported by the Basic Research Program from Ministry of Science and Technology of China, No. G1999054105special funds for Sino-France Center for Life Science and Genome Research from Chinese Academy of Sciences and Pasteur Institute in France
文摘AIM: To express the complete PreS region of HBV in E.coli with good solubility and stability, and to establish an effective method for purification of the recombinant PreS protein. METHODS: The complete PreS region (PreS1 and PreS2) was fused into a series of tags including glutathione S-transferase (GST), dihydrofolate reductase (DHFR), maltose binding protein (MBP), 6× histidine, chitin binding domain (CBD), and thioredoxin, respectively. Expression of recombinant PreS fusion proteins was examined by SDS-PAGE analysis and confirmed by Western blot. Two fusion proteins, thio-PreS, and PreS-CBD, with desirable solubility and stability, were subjected to affinity purification and further characterization. RESULTS: Recombinant PreS fusion proteins could be synthesized with good yields in E.coli. However, most of these proteins except for thio-PreS and PreS-CBD were vulnerable to degradation or insoluble as revealed by SDS-PAGE and Western blot. Thio-PreS could be purified by affinity chromatography with nickel-chelating sepharose as the matrix. However, some impurities were also co-purified. A simple freeze-thaw treatment yielded most of the thio-PreS proteins in solution while the impurities were in the precipitate. Purified thio-PreS protein was capable of inhibiting the binding of HBV virion to a specific monoclonal antibody against an epitope within the PreS1 domain. CONCLUSION: Increased solubility and stability of the complete PreS region synthesized in E.coli can be achieved by fusion with the thioredoxin or the CBD tag. A simple yet highly effective method has been established for the purification of the thio-PreS protein. Purified thio-PreS protein likely assumes a native conformation, which makes it an ideal candidate for studying the structure of the PreS region as well as for screening antivirals.
基金This work was supported by grants from the National Science Foundation of China (No. 81360372).
文摘Objective: To study the anti-angiogenesis effect of melittin on human hepatoma Mock/MHCC97-H cells by regulatingthe expression of cathepsin S (CatS) in vivo. Methods: Models of in situ transplantation tumor of Mock/MHCC97-Hcells and silencing cathepsin shRNA-CatS/ MHCC97-H cells in nude mice were established. The model mice wererandomly divided into four groups. In the A1 group, the mice were inoculated with shRNA-CatS/MHCC97-H cells andtreated with melittin. In the A2 group, the mice were inoculated with shRNA-CatS/MHCC97-H cells and treated withsaline. In the B1 group, the mice were inoculated with Mock/MHCC97-H cells and treated with melittin. In the B2 group,the mice were inoculated with Mock/MHCC97-H cells and treated with saline. The A1 and B1 group were injected withmelittin (80 mg/kg) intraperitoneally every day. The A2 and B2 group were injected with 0.2 mL normal salineintraperitoneally every day. After administration for 25 days, the animals were sacrificed. The tumor size and weight innude mice in each group were recorded. The expression of CD34 protein in the xenograft tumor tissues was detected byimmunohistochemistry. The expression of Cat S, VEGF-A, p-VEGFR2, Ras, Raf, p-Raf, MEK1, p-MEK1, ERK1/2 andp-ERK1/2 proteins were detected by western blot. Results: The B1 group had significantly smaller tumor volumes andlower tumor weights than the B2 group (both P 〈 0.001). There was no significant difference between the A1 group andA2 group in tumor volumes and weights. The number of CD34-positive microvessels in the B2 group was significantlyhigher than that in the A2 group (P 〈 0.001). The number of CD34-positive microvessels in the B1 group wassignificantly lesser than that in the A1 group (P 〈 0.001). Most strikingly, in the model featuring inoculation ofMock/MHCC97-H cells, CatS, VEGF-A, p-VEGFR2, Ras, Raf, p-Raf, MEK1, p-MEK1, ERK1/2 and p-ERK1/2expression were inhibited when treated with melittin. However, in the model featuring the inoculation ofshRNA-CatS/MHCC97-H cells, no such effects were observed with similar treatments. Conclusion: Melittin can inhibitthe growth of tumors and angiogenesis by blocking the CatS-VEGf-A signaling pathway.
文摘Objective To elucidate the effect of interleukin-1β (IL- 1β) on human growth hormone (hGH) gene expression in a rat somatotropic pituitary cell line MtT/S. Methods Stably transfected MtT/S cells were firstly established by transfecting 484-Lucl plasmid which contained hGH gene promoter --484 to +30 bp and luciferase reporter gene. The effect of IL-1β on hGH gene expression was determined by assaying the luciferase activities. RT-PCR method was also used to determine whether IL-1 recepor mRNA was expressed in MtT/S cells. Results The 10^3 U/mL IL-1β stimulated secretion and synthesis of GH, and promoted the 5'-promoter activity of GH gene in stably transfected MtT/SGL cells with the action of 1.38 times above the control. Among inhibitors of signaling transduction pathways, mitogen-activated protein kinase kinase (MAPKK/MEK) inhibitor PD98059 (40 μmol/L) and p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 (5 μmol/L) completely blocked the stimulatory effect of IL-1μ, and phosphatidylinositol-3-kinase (PI3-K) inhibitor LY294002 partly abolished the effect of IL-1μ. Western blot analysis further confirmed the activation of phosphorylated MEK and p38 MAPK in MtT/SGL cells. Neither over-expression of Pit- 1 nor inhibition of Pit- 1 expression affected induction of hGH promoter activity by IL-1μ. A series of deletion constructs of hGH promoter were created to identify the DNA sequence that mediated the effect of IL-1β, and results showed that the stimulatory effect of IL-1β was abolished following deletion of the --196 to -- 132 bp fragment. Conclusions IL-1β promotes GH secretion and synthesis in rat MtT/S somatotroph cells. The stimulatory effect of IL-1β on hGH gene promoter appears to require the activation of MEK, p38 MAPK, PI3-K, and a fragment of promoter sequence that spans the -196 to -132 bp of the gene, but it may be unlinked with Pit-1 protein.
文摘Adjuvant chemotherapy by S-1 following gastrectomy is considered standard treatment in Japan.Analysis of follow-up data have proved the effi cacy of S-1 admin-istration,and that hematological adverse events were relatively rare.Pyrimidine anti-metabolites,including S-1,have shown relatively lower risks for secondary hematological malignancies in comparison to alkylat-ing agents and topoisomerase-Ⅱ inhibitors.We here report a case of therapy-related leukemia after S-1 administration.A patient who had received S-1as the sole adjuvant chemotherapy was diagnosed with acute erythroid leukemia.To the best of our knowledge,our patient represents the fi rst report of S-1 induced acute leukemia.
文摘Objective Primary malignant melanomas of the liver are exceedingly rare.Only 19 cases have been reported in the literature worldwide.In this report,we describe our pathological findings and review the literature in order to improve our understanding of the disease and prevent misdiagnosis,as well as provide evidence for its treatment and prognosis.Methods We present a case of an isolated malignant melanoma of the liver in a 61-year-old male Chinese patient.Results Comprehensive dermatological and ophthalmological examinations did not reveal any evidence of a primary cutaneous or ocular lesion.Similarly,serial physical examinations,auxiliary examinations,and bone scans did not demonstrate any other lesions in the brain,respiratory tract,and gastrointestinal tract.Microscopic examination of the resected specimen revealed malignant melanoma,which was confirmed by immunohistochemical staining for S-100 protein(+),ki67(30%+),EMA(+),CD10(+),and HMB-45(++).Conclusion Primary malignant melanoma may occur in the liver,and should be considered when the histopathological appearance is atypical of other hepatic neoplasms.The diagnostic criteria for hepatic malignant melanoma depend mainly on the clinical,radiographic,and histopathological findings.Pathomorphology and immumohistochemical staining can be utilized to confirm the diagnosis.