1.Selecting EGF-binding Clones From a pⅧ-based Phage Display Library
Weigang TANG ; Jiada LI ; Changlin LI ; Keyi WANG ; Renbao GAN
Progress in Biochemistry and Biophysics 2000;27(4):432-434
Angiogenesis-related diseases involving EGF include acherosclerotic plaques, haemangioma, angiofibroma, tumor growth and arthritis. EGF may serve as a drug target and its antagonists may have important clinical applications.Peptide phage display libraries have been successfully applied in areas of finding ligands for enzymes, receptors, and many other molecules. A pⅧ-based peptide phage display library was panned with the cytokine EGF and several EGF-binding clones were selected based on ELISA and micropanning assays. The selected EGF-binders from peptide phage display library may be utilized in affinity chromatography in EGF downstream processing and even act as potential antagonists of EGF if their affinity is further improved through secondary library strategy.
2.Altered Redox Status in Erythrocytes From Hypertensive Subjects: Effect of (-)Epicatechin
SYED IBRAHIM RIZVI ; NAVNEET KUMAR
Progress in Biochemistry and Biophysics 2005;32(3):235-238
Hypertension is a major problem worldwide. There is much evidence to suggest that reactive oxygen species (ROS) radical may play a role in the development of organ damage associated with cardiovascular disease and hypertension. (-)Epicatechin, a member of tea catechins belonging to flavonoid group, is known to be a potent anti-oxidant.The study has been undertaken to evaluate the effect of (-)epicatechin on markers of oxidative stress: reduced glutathione (GSH) and membrane sulfhydryl (-SH) groups in erythrocytes from hypertensive patients. The effect of (-)epicatechin was also compared with a known anti-oxidant L-ascorbic acid. The erythrocyte intracellular GSH content and membrane -SH group content were significantly (P<0.01) decreased in hypertensive subjects. In vitro incubation with (-)epicatechin caused an increase in GSH and -SH content, the effect was more pronounced in hypertensive erythrocytes. Similar results were obtained with L-ascorbic acid. The observed decrease in the level of GSH and -SH groups in hypertension is an indicator of oxidative stress condition. Observation of an increase in red cell GSH content and the protection of membrane -SH group oxidation by (-)epicatechin in hypertensive subjects is a convincing reason to suggest that high dietary intake of foods rich in catechins may help to reduce oxidative stress and concomitant free radical damage in hypertensive patients.
3.Flavone-and Flavonol-Caused Apoptosis in Human Esophageal Cancer Cells by Inducing The Expression of PIG3
Progress in Biochemistry and Biophysics 2006;0(02):-
Two human esophageal cancer cell lines (KYSE-510 and OE33) were chosen as the tumor model to explore molecular mechanism of flavones and flavonols on induction of apoptosis. Effects of flavones (luteolin, apigenin, chrysin) and flavonols (quercetin, kaempferol, myricetin) on induction of apoptosis in KYSE-510 cells and OE33 cells were observed by DNA fragmentation, acridine orange staining and flow cytometry analysis. The results of real-time RT-PCR and Western-blot analysis showed that the treatment of KYSE-510 cells and OE33 cells with flavones and flavonols induced the expression of PIG3 at the mRNA and the protein levels. Western-blot analytical results further showed that induction of PIG3 caused apoptosis in both esophageal cancer cells through the mitochondrial pathway in a p53-independent manner, and p63 and p73 may be responsible for the induction of PIG3.
4.The Structure of Protein Phosphatase 2A and Its Inhibition of Tumorigenesis
Progress in Biochemistry and Biophysics 2006;0(02):-
Protein phosphatases are crucial for cell living. Protein phosphatase 2A (PP2A) is an important member of serine/theronine protein phosphatase family, which is involved in almost all biological processes in eukaryotic cell. The 3D structure of PP2A core enzyme and holoenzyme was solved in 2006. These results are significant instructions for us to further understand PP2A structure, interactions between PP2A subunits, and also interactions between PP2A and its binding proteins. In a series of studies, PP2A has been considered as a possible tumor inhibitor, which plays an essential role in tumorigenesis and cell transformation. Subunits composition and crystal structure of PP2A, specific carboxyl-terminal modification of PP2A catalytic subunit, interactions between the three subunits of PP2A, and its biological function as a new tumor inhibitor were summarized.
5.Progress of Bioinformatics Study in DNA Methylation
Progress in Biochemistry and Biophysics 2006;0(02):-
DNA methylation is an important epigenetic system. It plays many crucial roles in the gene regulation. With the development of the high-throughput detection techniques, the bioinformatics study has been an active hot topic in the research of DNA methylation. The major achievements and progress on the prediction of DNA methylation status, the mechanism that the majority of CpG islands are resistant to DNA methylation, the relationship between DNA methylation and other epigenetics, as well as the association between aberrant DNA methylation and the tumorigenesis were reviewed in this article.
6.Effects of TypeⅠ Gonadotropin-releasing Hormone(GnRH) and TypeⅡ GnRH on Cell Invasion in Human Choriocarcinomal JEG-3 Cells
Progress in Biochemistry and Biophysics 2006;0(03):-
Mammalian gonadotropin-releasing hormone(termed GnRHⅠ) is a decapeptide that plays key role in the process of reproduction.In addition to its well-known endocrine function, it has become evident that GnRHⅠ and the second GnRH subtype(termed GnRHⅡ) are potentially important autocrine and/or paracrine regulators in placental trophoblast cells.The effects of GnRHⅠ and GnRHⅡ on trophoblastic cell invasion were investigated in human choriocarcinoma cell line(JEG-3) by the methods of invasion assay, RNA interference, Western blot and Real-time PCR.The data revealed that exogenous native peptide of these two forms of GnRH significantly induced the expression of typeⅠ GnRH receptor(GnRHRⅠ) in JEG-3 cells.The specific siRNA for GnRHR Ⅰ was capable of blocking the invasion-promoting effect of GnRHⅠ, but did not influence the effect of GnRHⅡ.The data suggested that the two hormones may be elicited by distinct receptors.Interference of the activities of ERK and JNK was capable of attenuating GnRH Ⅰ and Ⅱ-induced MMP-2 expression and trophoblast invasion, indicating that activation of ERK and JNK are required in both GnRH Ⅰ and GnRH Ⅱ-mediated MMP-2 production and invasion-promoting effect in human trophoblastic cells.
7.The Expression and Functional Research of PIWIL4 in Human Ovarian Cancer
Limin GUO ; Min LIU ; Xin LI ; Hua TANG
Progress in Biochemistry and Biophysics 2006;0(03):-
To explore the expressional information of PIWIL4 in human ovarian cancer, semi-quantitative reverse transcription polymerase chain reaction(semi-qRT-PCR) was used to detect the mRNA expression level of PIWIL1, PIWIL2, PIWIL3 and PIWIL4 in human ovarian clear cell carcinoma ES-2 cells.Meanwhile, in human ovarian cancer and adjacent normal tissues, the mRNA expression of PIWIL4 was determined.Then, PIWIL4-siRNA, which was designed to target PIWIL4 and chemical synthesized, was transfected into ES-2 cells with lipofectamine.MTT assay and clone formation assay were used to investigate the effects of PIWIL4-siRNA on the cell growth activity and proliferation capacity of ES-2 cells.Experimental results showed that the mRNA expression level of PIWIL4 was the highest compared to PIWIL1, PIWIL2 and PIWIL3 in ES-2 cells(P
8.The Birth,Development and Applications of Domain-Domain Interaction Databases
Progress in Biochemistry and Biophysics 2006;0(03):-
Domains are evolutionarily conserved sequence units and they are structural and functional building blocks of proteins.Interaction between two proteins typically involves binding between specific domains, and identifying interacting domain pairs is an important step towards thoroughly understanding protein function and evolution, constructing protein-protein interaction(PPI) networks, and analyzing pathway at the domain level.A number of interacting and/or functionally linked domain pairs have been identified and the information was organized and hosted in many domain-domain interactions(DDI) databases with the help of further mining experimental data and computational predictions from various input data.First, the 8 computational predicting methods used to acquire DDI data will be introduced.Then the introduction of DDI public databases, including 3DID, iPfam, InterDom, DIMA and DOMINE will be given.And finally, some examples are described about applications of DDI in computational predicting interacting protein pairs, assessment of the reliability for PPI, protein domain annotation, and in pathway study.
9.The Inhibitory Effect of OGT Gene Expression on The Level of tau Phosphorylation
Jiangyong YANG ; Jianlan GU ; Jianhua SHI ; Fei LIU ; Qin SHEN
Progress in Biochemistry and Biophysics 2006;0(03):-
To investigate the effect of OGT expression inhibited by RNAi on the alteration of tau phosphorylation and glycosylation level in HEK293T cells.The siRNAs targeting OGTgene(OGT-siRNA1~3) were designed and chemically synthesized.The OGT-siRNA1~3 were transfected into HEK293T cells via lipofectamine2000.The efficacy of RNA interference was detected by RT-PCR.The fluorescence of GFP/OGT was counted by fluorescence microscopy after pEGFP/OGT and OGT-siRNA1~3 cotransfected to HEK293T cells for 24 h.The level of tau phosphorylation and glycosylation were detected by Western blot after Plasmid pCI/tau441 and the siRNA cotransfected HEK293T cells for 48 h.OGT-siRNA3(100 nmol/L) could effectively downregulate the expression of OGT gene compared with Mock group(80.0% at mRNA level and 51.3% at protein level).The level of phosphorylation at various sites of the tau was significantly upregulated and the glycosylation was downregulated following the inhibition of OGT gene expression.There is an apparent negative correlation between the modification of phosphorylation and glycosylation of tau protein, the deficient in glucose uptaken/metabolism may be an important pathogenesis of AD.
10.Cloning,Expression and Sub-cellular Localization of APOBEC-3F and -3G and Their Effect on HBV
Gefei WANG ; Cheng PENG ; Weizhong LI ; Gang XIN ; Yun SU ; Youying CHEN ; Guimei LIN ; Kangsheng LI
Progress in Biochemistry and Biophysics 2006;0(03):-
APOBEC(apolipoprotein B mRNA-editing enzyme catalytic-polypeptide) family members were reported as innate immune molecules with anti-viral activity for many viruses, such as HIV and HBV.In order to understand the function of APOBEC, the APOBEC-3F and-3G were cloned, expressed, and the sub-cellular localization of them was detected.The genes of APBEC-3F and-3G were cloned from PHA-stimulated PMBC and expressed in the MDCK cell by transfection.The sub-cellular localization of APOBEC-3F and-3G were detected by immunofluorescence.APOBEC-3F and-3G were cloned by RT-PCR and confirmed by DNA sequencing.The immunofluorescence indicated APOBEC-3F and-3G were located in the cytosal.APOBEC-3F and-3G could inhibit HBV replication effectively in HepG2.2.15 cell.APOBEC-3F and-3G could not be trans-located into nuclear by nuclear location signal(NLS) or bi-NLS(B-NLS).These results will help the future research on the function of APOBEC.