Gene clone and functional identification of sterol glycosyltransferases from Paris polyphylla var. yunnanensis / 中国中药杂志

In this study, the authors cloned a glycosyltransferase gene PpUGT2 from Paris polyphylla var. yunnanensis with the ORF length of 1 773 bp and encoding 590 amino acids. The phylogenetic tree revealed that PpUGT2 belonged to the UGT80A subfamily and was named as UGT80A49 by the UDP-glycosyltransferase(UGT) Nomenclature Committee. The expression vector pET28a-PpUGT2 was constructed, and enzyme catalytic reaction in vitro was conducted via inducing protein expression and extraction. With UDP-glucose as sugar donor and diosgenin and pennogenin as substrates, the protein was found with the ability to catalyze the C-3 hydroxyl β-glycosylation of diosgenin and pennogenin. To further explore its catalytic characteristic, 15 substrates including steroids and triterpenes were selected and PpUGT2 showed its activity towards the C-17 position of sterol testosterone with UDP-glucose as sugar donor. Homology modelling and molecule docking of PpUGT2 with substrates predicted the key residues interacting with ligands. The re-levant residues of PpUGT2-ligand binding model were scanned to calculate the corresponding mutants, and the optimized mutants were obtained according to the changes in binding affinity of the ligand with protein and the surrounding residues within 5.0 Å of ligands, which had reference value for design of the mutants. This study laid a foundation for further exploring the biosynthetic pathway of polyphyllin as well as the structure of sterol glycosyltransferases.

Progress of Basic and Clinical Research on Mucin-type O-Glycosylation and Colorectal Cancer / 胃肠病学

O⁃glycosylation is a common post⁃translational modification of mucins, widely present in both normal and tumor cells. In colorectal cancer (CRC) cells, there is a varying degree of dysregulation in O ⁃ glycosylation ⁃ related glycosyltransferases, molecular chaperones, and surface Tn antigen, sTn antigen, and T antigen. These dysregulations play a distinctive role in the occurrence and development of CRC, including invasion and metastasis, abnormal apoptosis and proliferation, immune escape, etc. They are extensively studied as novel tumor biomarkers and potential therapeutic targets. This article provides a comprehensive review of progress of research on mucin⁃type O⁃glycosylation and its relevance to the occurrence and development of CRC and its clinical application.

Unraveling the serial glycosylation in the biosynthesis of steroidal saponins in the medicinal plant Paris polyphylla and their antifungal action

Sugar-sugar glycosyltransferases play important roles in constructing complex and bioactive saponins. Here, we characterized a series of UDP-glycosyltransferases responsible for biosynthesizing the branched sugar chain of bioactive steroidal saponins from a widely known medicinal plant Paris polyphylla var. yunnanensis. Among them, a 2'-O-rhamnosyltransferase and three 6'-O-glucosyltrasferases catalyzed a cascade of glycosylation to produce steroidal diglycosides and triglycosides, respectively. These UDP-glycosyltransferases showed astonishing substrate promiscuity, resulting in the generation of a panel of 24 terpenoid glycosides including 15 previously undescribed compounds. A mutant library containing 44 variants was constructed based on the identification of critical residues by molecular docking simulations and protein model alignments, and a mutant UGT91AH1Y187A with increased catalytic efficiency was obtained. The steroidal saponins exhibited remarkable antifungal activity against four widespread strains of human pathogenic fungi attributed to ergosterol-dependent damage of fungal cell membranes, and 2'-O-rhamnosylation appeared to correlate with strong antifungal effects. The findings elucidated the biosynthetic machinery for their production of steroidal saponins and revealed their potential as new antifungal agents.

Research Progress on Relationship Between ABO Blood Group and Gastric Cancer / 胃肠病学

Gastric cancer is the most commonly seen gastrointestinal tumor in China. The risk factors of gastric cancer include regional environment, diet and living factors, Helicobacter pylori infection, precancerous lesions, heredity, etc. Studies have shown that ABO blood group system, as a genetic marker, has a certain relationship with the occurrence and development of gastric cancer. Since the relationship between type A blood and gastric cancer was first proposed in the 1950s, a large number of studies on blood type and gastric cancer have been carried out, but the results are not consistent. This article reviewed the research progress on relationship between ABO blood group and gastric cancer and its mechanisms.

Association between the alteration of serum N-glycan profile and the change of glycosyltransferase expression in liver tissue in patients with hepatitis B virus-related hepatocellular carcinoma / 临床肝胆病杂志

ObjectiveTo investigate the potential mechanism of serum N-glycan alterations in patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) by measuring serum N-glycan profile and comparing glycosyltransferase gene expression between HCC tissue and adjacent tissue. MethodsThe samples of HCC tissue, adjacent tissue, and normal liver tissue were collected from 34 patients with HBV-related HCC who were admitted to Chinese PLA General Hospital, and serum samples were also collected. Among these 34 patients, 8 were randomly selected and their serum samples were established as HCC experimental group, and the serum samples of 20 healthy adults were established as control group. DNA sequencer-aided fluorophore-assisted carbohydrate electrophoresis was used to analyze serum N-glycan profile in the HCC experimental group and the control group. Quantitative real-time PCR was used to measure the mRNA expression of 8 glycosyltransferase genes (FUT3, FUT4, FUT6, FUT7, FUT8, Gn-TIII, Gn-TIVa, and Gn-TV) in the HCC tissue and adjacent tissue of 34 patients with HBV-related HCC, and Western blot was used to measure the expression of corresponding proteins. The independent samples t-test was used for comparison of continuous data between two groups. ResultsCompared with the control group, the HCC experimental group had a significant increase in the abundance of N-glycan peak9 (NA3Fb) in serum(t=-2.514,P＜0.05). There were significant differences in the mRNA expression of FUT8, Gn-TIVa, and Gn-TV between HCC tissue and adjacent tissue, and the mRNA and protein expression levels of FUT8 and Gn-TV in HCC tissue were significantly higher than those in adjacent tissue (FUT8 mRNA: 1.50±0.34 vs 0.65±0.11, t=-2.354，P=0.022; Gn-TV mRNA: 3.57±0.64 vs 1.33±016, t=-3.384,P=0001; FUT8 protein: 0.70±0.11 vs 0.083±0.017, t=9.555,P=0.001; Gn-TV protein: 1.33±0.19 vs 0.60±0.15, t=5.097,P=0.007). The mRNA expression level of Gn-TIVa in HCC tissue was significantly higher than that in adjacent tissue (2.90±0.47 vs 1.68±0.19, t=-2.403,P=0.019), but there was no significant difference in the protein expression level of Gn-TIVa between HCC tissue and adjacent tissue (052±0.24 vs 0.24±0.11,t=1.833, P=0.141). The changes of glycosyltransferase gene expression in HCC tissue were consistent with the alteration of serum N-glycan profile. ConclusionSerum N-glycan alterations in patients with HBV-related HCC may be closely associated with the upregulated expression of the glycosyltransferase genes FUT8, Gn-TIVa, and Gn-TV in HCC tissue.

Full-length Cloning and Protein Expression Analysis of Glycosyltransferases Gene SaUGT1/SaUGT2 in Sorbus aucuparia / 中国实验方剂学杂志

Objective: To obtain the glycosyltransferase gene involved in modification reaction of phytoalexin from Sorbus pohuashanensis suspension cell,and conduct sequence analysis and prokaryotic expression analysis. Method: Based on the transcriptome data,specific primers were designed to obtain 2 cDNA sequences of SaUGTs genes,construct prokaryotic expression vector HIS-MBP-pET28a-SaUGTs and induce the expression of recombinant SaUGTs protein. Result: SaUGT1 and SaUGT2 sequences were cloned and obtained from glycosyltransferases,then bioinformatic analysis of the sequence and prokaryotic expression analysis were conducted. SaUGT1 gene contained 1 458 bp open reading frame (ORF),encoding a polypeptide of 485 amino acids,with a relative molecular weight of 54.27 kDa and theoretical isoelectric point (pI) of 5.50.SaUGT2 gene contained 1 431 bp ORF,encoding a polypeptide of 476 amino acids,with a relative molecular weight of 53.49 kDa and theoretical pI of 5.63. Bioinformatics analysis indicated that SaUGT1 and SaUGT2 protein had no signal peptide,and the conserved domains of glycosyltransferase family were detected. Phylogenetic results showed that SaUGT1 and SaUGT2 proteins had the closest relationship with the UGT85 family of A. thaliana. Differential expression analysis revealed that the relative expression levels of SaUGT1 and SaUGT2 were increased significantly after being induced by yeast extract (YE), with the highest expression level found at 24 h and 12 h. The recombinant SaUGT1 and SaUGT2 proteins were successfully expressed in Escherichia coli DE3 cells and finally,the recombinant SaUGT1 and SaUGT2 proteins were purified through Ni2+ affinity chromatography. Conclusion: The glycosyltransferase gene was cloned from the S. aucuparia for the first time,and the prokaryotic expression vector was successfully constructed,laying foundation for further study of the function of this gene.

Structural diversity and biological importance of ABO, H, Lewis and secretor histo-blood group carbohydrates

ABSTRACT ABO, H, secretor and Lewis histo-blood system genes control the expression of part of the carbohydrate repertoire present in areas of the body occupied by microorganisms. These carbohydrates, besides having great structural diversity, act as potential receptors for pathogenic and non-pathogenic microorganisms influencing susceptibility and resistance to infection and illness. Despite the knowledge of some structural variability of these carbohydrate antigens and their polymorphic levels of expression in tissue and exocrine secretions, little is known about their biological importance and potential applications in medicine. This review highlights the structural diversity, the biological importance and potential applications of ABO, H, Lewis and secretor histo-blood carbohydrates.

Glycosylation and biomarkers in primary liver cancer / 中华检验医学杂志

Primary liver cancer (PLC) is the second leading cause of cancer death in China,and is one of the most serious threats to people's health.Early diagnosis and treatment can significantly improve the prognosis of PLC.Abnormal glycosylation is reported to be closely related to the genesis and development of malignant tumors.With the advent of modern proteomic and glycomic methodologies,several alterations in fucosylation,sialylation,and glycan branching have been observed in serum of patients with PLC.Altered glycosylation profiles,glycosyltransferases and glycosylated proteins could be screened and used as potential serum markers for early diagnosis,progression monitoring and prognosis evaluation of PLC.

Construction of a glycoengineering yeast overexpressing N-glycosyltransferase / 军事医学

Objective To obtain a strain of glycoengineering yeast with higher N-glycosylation efficiency by overexpressing N-glycosyltransferase.Methods Through the selecting marker URA3 gene, a new glycoengineering yeast strain named 4-32-STT3D was constructed, which could overexpress the Leishmania major N-glycosyltransferase staurosporine and temperature sensitivity3 D subunit(STT3D) under the control of an inducible alcohol oxidase 1(AOX1) promoter.We analyzed the N-glycosylation status of anti-human epidermal growth factor receptor 2 ( HER2 ) antibody and granulocyte macrophage colony stimulating factor (GM-CSF) expressed in 4-32-STT3D using SDS-PAGE,Western blotting and peptide-N-asparigineamidase F(PNGase F).Finally the effect of STT3D on the growth rate of glycoengineering yeast was detected.Results SDS-PAGE showed that anti-HER2 antibody expressed in 4-32-HL had two components:the first one with a relative molecular mass 55 ×103 was glycosylated,while the second one with 50 ×103 was non-glycosylated,but anti-HER2 antibody expressed in 4-32-HL-STT3D had the component of 55 ×103 only without any non-glycosylated 50 ×103 .The above components became 50 ×103 with the digestion of PNGaseF.All of them proved to be antibodies by Western blotting.As a report protein,GM-CSF expressed in 4-32-GM-CSF had two components: 22 ×103 and 20 ×103, while in 4-32-GM-CSF-STT3D there was only one with 22 ×103 .All these components became 18 ×103 with the digestion of PNGase F.Statistical analysis showed that without induction,STT3D had no effect on the growth rate of glycoengineering yeast, while great effect was observed when STT3D was induced.Conclusion Glycoengineering yeast with the overexpression of N-glycosyltransferase has higher N-glycosylation efficiency.

Metastasis and drug resistance of human hepatocarcinoma cells mediated by glycogenes and N-glycans / 国际肿瘤学杂志

Objective To identify the relationship among glycogenes,N-glycans and hepatocarcinoma metastasis and drug resistance by studying the differential expressions of glycogenes and N-glycans in MHCC97-H and MHCC97-L human hepatocarcinoma cell lines,and to confirm the novel target of hepatocarcinoma metastasis and anti-tumor therapy.Methods Real-time PCR was used to quantitatively analyze glycogenes and fluorescein isothiocyanate (FITC)-lectin was used to analyze glycans characteristics.RNA interference approach was used to interfere the glycogenes,and the invasive ability in vitro and drug susceptibility of MHCC97-H cells were detected before and after interference.Modification of N-glycosylation (tunicamycin and PNGase F treatment) was done,and the invasiveness in vitro,tumorigenicity in vivo and drug susceptibility of MHCC97-H cells were detected before and after modification.Results The expressions of glycogenes and glycans were different in MHCC97-H cells and MHCC97-L cells.The silence of MGAT5 in MHCC97-H cells inhibited invasion ability and increased sensitivity to 5-fluorouracil in vitro(t =7.312,P ＜ 0.05).Modification of N-glycosylation decreased MHCC997-H cells invasion ability in vitro and tumorigenicity in vivo and increased sensitivity to 5-fluorouracil.Conclusion The differential expressions of glycogens and N-glycans in human hepatocarcinoma cell lines correlate with tumor invasion and drug resistance,and they are expected to be novel targets of tumor chemotherapy.

Effect of ART 1 gene silencing by RNA interference on the proliferation of mouse colon carcinoma cells and its possible mechanism / 肿瘤

Objective: To investigate the effect of ART 1 (arginine-specific adenosinediphosphateribosyltransferase 1) gene silencing by shRNA (short hairpin RNA) interference on the proliferation ability of mouse colon cancer CT26 cells, and to explore its possible mechanism. Methods: It was confirmed that ART1 expression existed in CT26 cells by immunofluorescence assay. Lentivirus of ART1-shRNA was infected into mouse colon carcinoma CT26 cells. The CT26 cells uninfected or infected with a negative NC-shRNA (control-shRNA) served as the controls. The expression of ART1 mRNA was detected by RTPCR, and the expressions of ART1, RhoA, c-myc, and c-fos proteins were examined by Western blotting. The cell proliferation in each group was measured by CCK8 (cell counting kit-8) assay. Results: It was determined that ART1 expression existed in the CT26 cells. Lentivirus of ART1-shRNA or NC-shRNA was infected into CT26 cells successfully, and the CT26 cell line with stable low-expression of ART1 was successfully established. Compared with CT26 cells infected with NC-shRNA lentivirus or those were un-infected, the expression of ART1 mRNA was significantly reduced in CT26 cells infected with ART1- shRNA lentivirus (P < 0.01), and the protein expression levels of ART1, RhoA, c-myc, and c-fos were all obviously decreased (P < 0.01). The inhibition rate of cell proliferation of CT26 cells infected with ART1-shRNA lentivirus was markedly increased compared with the control groups (P < 0.01). Conclusion: RNA interference targeting ART 1 gene can inhibit the proliferation ability of mouse colon carcinoma CT26 cells. This effect probably associates with the down-regulation of the expressions of RhoA and its downstream effectors c-myc and c-fos after silencing the expression of ART 1 gene. Copyright © 2012 by TUMOR.

Transcriptional Regulation of Proteoglycans and Glycosaminoglycan Chain-synthesizing Glycosyltransferases by UV Irradiation in Cultured Human Dermal Fibroblasts

Various kinds of glycosaminoglycans (GAGs) and proteoglycans (PGs) have been known to be involved in structural and space-filling functions, as well as many physiological regulations in skin. To investigate ultraviolet (UV) radiation-mediated regulation of GAGs and PGs in cultured human dermal fibroblasts, transcriptional changes of many types of PGs and GAG chain-synthesizing enzymes at 18 hr after 75 mJ/cm2 of UV irradiation were examined using quantitative real-time polymerase chain reaction methods. Hyaluronic acid synthase (HAS)-1, -2, and -3 and hyaluronidase-2 mRNA expressions were significantly increased by UV irradiation. Expressions of lumican, fibromodulin, osteoglycin, syndecan-2, perlecan, agrin, versican, decorin, and biglycan were significantly decreased by UV irradiation, while syndecan-1 was increased. Expressions of GAG chain-synthesizing glycosyltransferases, xylosyltransferase-1, beta1,3-glucuronyltransferase-1, beta1,4-galactosyltransferase-2, -4, exostosin-1, chondroitin polymerizing factor, and chondroitin sulfate synthase-3 were significantly reduced, whereas those of beta1,3-galactosyltransferase-6, beta1,4-galactosyltransferase-3, -7, beta-1,3-N-acetylglucosaminyltran sferase-2, and -7 were increased by UV irradiation. Heparanase-1 mRNA expression was increased, but that of heparanase-2 was reduced by UV irradiation. Time-course investigation of representative genes showed consistent results. In conclusion, UV irradiation may increase hyaluronic acid production through HAS induction, and decrease other GAG productions through downregulation of PG core proteins and GAG chain-synthesizing glycosyltransferases in cultured human dermal fibroblasts.

Un caso de grupo sanguíneo raro: fenotipo p / A rare blood group: p phenotype

Un individuo con un fenotipo eritrocitario raro carece de uno o varios antígenos presentes en la mayor parte de la población de pertenencia. Cuando presenta el anticuerpo correspondiente, se pueden producir complicaciones perinatales, transfusionales y/o transplantológicas. Se presenta el caso de una embarazada aloinmunizada derivada a nuestro servicio en la semana 12 de su tercera gesta para su evaluación y seguimiento. El diagnóstico inmunohematológico le asignó el excepcional fenotipo "p" (aproximadamente 1/200 000 individuos), asociado con una mayor tasa de abortos espontáneos y a reacciones transfusionales graves cuando se transfunden unidades incompatibles. El estudio del gen A4GALT demostró la presencia de la mutación c.752C > T en doble dosis. Esta mutación lleva a un cambio de una prolina por una leucina en el residuo 251 de la 4-α-galactosiltransferasa. Por parto inducido por sufrimiento fetal, nace a las 36 semanas una bebé con prueba de antiglobulina (Coombs) directa negativa, eluido reactivo, con ictericia que requirió luminoterapia. Una semana después el neonato fue externado sin secuelas aparentes. Posteriormente, a raíz de una cirugía inminente y la improbabilidad de encontrar sangre compatible, se elaboró un plan para cubrir las posibles demandas. Este caso pone en evidencia la necesidad de contar a nivel nacional con un laboratorio de referencia de inmunohematología y un banco de sangre de grupos raros, que permita resolver con celeridad situaciones que requieran transfundir a estos individuos.

A rare blood group is usually defined as the absence of a high prevalence antigen or the absence of several antigens within a single blood group system. These individuals may develop clinically significant red cell antibodies to the high incidence red cell antigens they lack. A 33-year-old alloimmunized woman was referred to our center at the 12th week of her third pregnancy for evaluation and follow up. The laboratory work-up grouped her as belonging to "p" phenotype, associated with difficulties to find compatible blood for transfusion and a high incidence of recurrent miscarriage. At 36 weeks, a baby girl was born by induced labor due to fetal suffering. With a negative direct antiglobulin test but a positive elution test, she was in the neonatology ward for one week receiving luminotherapy. Homozygosity for a missense mutation at position 752 (c.752C > T) in the A4GALT gene was found to be responsible for the p phenotype. This mutation changes a proline to a leucine at codon 251 of the 4-α-galactosyltransferase. Recently, due to an imminent chirurgical intervention and the impossibility to have compatible blood available for transfusion, an autologous donation plan was designed to satisfy probable demand. This case showed the need for blood bank facilities capable to respond satisfactorily to these situations in Argentina. This would facilitate the storage of cryopreserved blood from individuals with rare blood groups for homologous use or to develop rare blood donors programs.

Glucanos extracelulares bacterianos: estructura, biosíntesis y función / Extreacellular bacterial glucans: structure, biosynthesis and function

La caries dental es una de las enfermedades más frecuentes en el ser humano. En su etiología multifactorial, desempeñan un papel importante determinadas bacterias cariogénicas, que en interacción con la superficie del diente promueven su desmineralización. Dentro de los mecanismos mediadores de la adhesión bacteriana, se encuentra la producción de polisacáridos extracelulares bacterianos. En particular los glucanos sintetizados por las glucosiltransferasas, no solo permiten la adherencia, sino que también constituyen una fuente nutricional para las bacterias, por lo tanto, la actividad de dichas enzimas se considera un factor de virulencia bacteriana en la caries dental. Esta revisión bibliográfica tiene el objetivo de esclarecer los aspectos relacionados con la estructura, biosíntesis y función de los glucanos, y enfatizar en la aplicación de estos conocimientos en la prevención de la caries dental(AU)

Dental caries is one of the most common diseases in the human being. Certain cariogenic bacteria play an important role in its multifactorial etiology, since in their interaction with the dental surface they promote its demineralization. The production of extracellular bacterial polyssacharides is among the mechanisms mediating bacterial adhesion. The glucans synthesized by glycosyltransferases not only allow the adherence, but they also are a nutritional source for bacteria and that's why the activity of such enzymes is considered a factor of bacterial virulence in dental caries. This bibliographic review is aimed at making clear the aspects related to the structure, biosynthesis and function of glucans and at giving emphasis to the application of this knowledge in the prevention of dental caries(AU)

Identification of a novel Bx allele in a Chinese Han individual with B subgroup / 中国输血杂志

T missense mutation in exon 7. No novel point mutation at exons 6 and 7 of ABO gene was detected in the other four samples with B subgroup. Conclusion We define this allele as a novel B allele in Chinese Han individuals. The mutation of this novel allele in which the nucleotide changes from C to T at position 721 in exon 7, resulting in an amino acid change from Arg to Trp, results in the decrease of the enzyme activity. It indicates that the alteration of amino acid at position of 241 is critical to the activity of glycosyltransferases.