检索结果-南通市图书馆

Negative regulation of TGF-β signaling in development

在线全文

学校读者我要写书评

暂无评论

Cell Research 2004年第6期14卷 441-449页

作者： Ye Guang CHEN, An Ming MENG The State key laboratory of {2. and membrane biotechnology, department of biological sciences and biotechnology, tsinghua university, beijing 100084, china department of biological {2.s and biotechnology The State Key Laboratory of Biomembrane and Membrane Biotechnology Tsinghua University Beijing China

The TGF-β superfamily members have important roles in controlling patterning and tissue formation in both invertebrates and vertebrates. Two types of signal transducers, receptors and Smads, mediate the signaling to regulate expression of their target genes. Despite of the relatively simple signal transduction pathway, many modulators have been found to contribute to a tight regulation of this pathway in a variety of mechanisms. This article reviews the negative regulation of TGF-β signaling with focus on its roles in vertebrate development.

关键词： TGF-β BMP Nodal Activin antagonist development negative regulation.

Electrophysiological research of synapse formation from beginning to maturity

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese science Bulletin 1998年第1期43卷 55-59页

作者： XIE Zuoping and ZHENG Yufang State key laboratory of {2. and membrane Biotechnique department of biological sciences and biotechnology, tsinghua university, beijing 100084, china State key laboratory of {2. and membrane Biotechnique Tsinghua University Beijing China department of biological {2.s and biotechnology Tsinghua University Beijing China

The development of synapses is an important question in neurobiology. We employ patchclamp technique to record MEPCs and EPCs of myoballs in Xenopus cell culture. The rate of EPC/MEPC is related with synapses maturation. Accordingly, we define the mature synapses as those whose rate of presynaptic membrane’s EPC to MEPC is more than 8. The process of maturation needs about 2.5 h after neurites contact with myoballs. We divide the development of synapses into three stages: young, developing and mature. The neurotransmitters stack gradually and increase by hundreds of times along with young synapses growing into maturity. So the process of synapses maturation should include presynaptic membrane specialization, postsynaptic membrane specialization and neurotransmitters stack.

关键词： definition of mature synapse α latrotoxin (α LTX) neurotransmitter stack.

A measurement error model for microarray data analysis

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2005年第7期15卷 614-620页

作者： ZHOU Yiming and CHENG Jing ( department of biological {2.s and biotechnology, tsinghua university, beijing 100084, china State key laboratory of biomembrane and membrane biotechnology, tsinghua university, beijing 100084, china National Engineering Research Center for beijing Biochip Technology, 18 Life {2. Parkway, beijing 102.06, china) department of biological {2.s and biotechnology Tsinghua University Beijing 100084 China State key laboratory of {2. and membrane biotechnology Tsinghua University Beijing 100084 China National Engineering Research Center for beijing Biochip Technology 18 Life Science Parkway Beijing 102206 China

Microarray technology has been widely used to analyze the gene expression levels by detecting fluorescence intensity in a high throughput fashion. However, since the measurement error produced from various sources in microarray experiments is heterogeneous and too large to be ignored, we propose here a measurement error model for microarray data processing, by which the standard deviation of the measurement error is demonstrated to be linearly increased with fluorescence intensity. A robust algorithm, which estimates the parameters of the measurement error model from a single microarray without replicated spots, is provided. The model and algorithm for estimating of the parameters from a given data set are tested on both the real data set and the simulated data set, and the result has been proven satisfactory. And, combining the measurement error model with traditional Z-test method, a full statistical model has been developed It can significantly improve the statistical inference for identifying differentially expressed genes.

关键词： microarray measurement error model parameter estimation differentially expressed genes.

Structure and regulatory function of plant transcription factors

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese science Bulletin 2001年第4期46卷 271-278页

作者： LIU Qiang, ZHANG Guiyou & CHEN Shouyidepartment of biological {2. and biotechnology, tsinghua Univorsity, beijing 100084, china department of biological {2. and biotechnology, State laboratory of {12. and membrane biotechnology, tsinghua university, beijing 100084, china Institute of Genetics, Chinese Academy of {2.s, beijing 100101, china department of biological {2. and biotechnology Tsinghua University Beijing China department of biological {2. and biotechnology State Laboratory of Biomembrane and Membrane Biotechnology Tsinghua University Beijing China Institute of Genetics Chinese Academy of Sciences Beijing China

The expression of inducible genes in plants is regulated by specific transcription factors at the transcrip-tional level. A typical transcription factor usually contains a DNA-binding domain, a transcription regulation domain, a dimerization site and a nuclear localization domain. These functional domains define the characteristic, localization and regulatory role of a transcription factor. Transcription factors recognize and bind to specific cis-acting elements or interact with other proteins, and then activate or repress the transcription of target genes by their functional domains. In recent years, elucidation on the structure and function of transcription factors has become an important subject in plant molecular biology.

关键词： transcription factor DNA-binding domain cis-acting element.

MEK inhibitor PD98059 acutely inhibits synchronized spontaneous Ca2.oscillations in cultured hippocampal networks

在线全文

学校读者我要写书评

暂无评论

Acta Pharmacologica Sinica 2006年第7期27卷 869-876页

作者： Yan-fang RUI~1 Zhao-hui SUN~2.Jia-ping GU~1 Zhong-hua SHENG~1 Xiang-ping HE~1 Zuo-ping XIE~(1,3)1 department of biological {2. and biotechnology,State key laboratory of biomembrane and membrane biotechnology,tsinghua university beijing 100084,{12. 2.Institute of Neurological Disorders,Life {2. and Medical department,tsinghua university,beijing 100084,{12. department of biological {2. and biotechnology State Key Laboratory of Biomembrane and Membrane Biotechnology Tsinghua University Beijing China Life science and Medical department Institute of Neurological Disorders Tsinghua University Beijing China

Aim:To investigate the changes in synchronized spontaneous Ca2.oscillationsinduced by mitogen-activated protein kinase kinase（MEK）inhibitor PD98059 atdifferent concentrations in cultured hippocampal ***:Hippocam-pal neurons in culture for 1-2.weeks were used for this *** activities of these hippocampal neurons were examined by Ca2.imagingusing calcium-sensitive *** inhibitor PD98059（10,30,and 60μmol/L）andSB2.2.74（10 and 60μmol/L）,a negative control for mitogen-activated proteinkinase（MAPK）cascade study,were applied to the cells under the microscopewhile imaging was taking ***:PD98059 at a lower concentration of 10μmol/L had little effect on the Ca2.*** the higher concentration of 30μmol/L,5 min after application of PD98059,the spike frequency was decreased to2..38%±7.40%（mean±SEM,n=16,P2.2.74 atconcentrations of 10 and 60 μmol/L had little inhibition effect on the Ca2.***:These results indicate that PD98059 inhibits synchronized sponta-neous Ca2.oscillation through inhibition of MEK,which hints that the MAPKcascade is required to maintain synchronized spontaneous Ca2.oscillation.

关键词： PD98059 MEK calcium oscillation

In vitro and in vivo evaluation of a novel oral insulin formulation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Pharmacologica Sinica 2006年第10期27卷 1382-1388页

作者： Er-li MA Hong MA Zheng LIU Chang-xue ZHENG Ming-xing DUAN~2.State key laboratory of Bio-{2. and biotechnology,department of biological sciences and biotechnology,tsinghua university beijing 100084,china department of biological {2.s and biotechnology State Key Laboratory of Bio-membrane and Biotechnology Tsinghua University Beijing China

Aim:To develop a stable self-emulsifying formulation for oral delivery of ***:Caco-2.cell line and diabetic beagles were used as in vitro and in vivomodels to study the absorption mechanism and the hypoglycemic efficacy of *** addition,various physicochemical parameters of the formulationsuch as droplet size,insulin encapsulation efficiency and stability were ***:This formulation enabled changes in barrier properties of Caco-2.onolayers,as referred by transepithelial electrical resistance(TEER)and appar-ent permeability coefficients(Papp)of the paracellular marker ranitidine(2.-foldgreater than control)but not transcellular marker propranolol,suggesting that theopening of tight junctions was *** diabetic beagle dogs,the bioavailabilityof this formulation was up to 15.2. at a dose of 2.5 IU/kg in comparison with thehypoglycemic effect of native insulin(0.5 IU/kg)delivered by ***:This formulation,recently approved by the china StateFood and Drug Administration to enter clinical trials,was stable,degradation-protected and absorption-enhanced,and provided a promising formulation fororal insulin delivery.

关键词： insulin oral delivery Caco-2 diabetic beagles

PTEN,a general negative regulator of cyclin D expression

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Cell Research 2007年第4期17卷 291-292页

作者： Eirong Diao~1 Ye-Guang Chen ~1State key laboratory of {2. and membrane biotechnology,department of biological sciences and biotechnology Tsing-hua Universiry,beijing 100084,china department of biological {2.s and biotechnology State Key Laboratory of Biomembrane and Membrane Biotechnology Tsinghua University Beijing China

The tumor-suppressor phosphatase with tensin homol-ogy(PTEN)is frequently mutated in many malignanciesand is one of the most well studied tumor suppressor genes[1,2..PTEN,a lipid and protein dual phosphatase,plays avital role in embryonic development,cell growth,apoptosisand cell *** well-known function of PTEN isphosphatidylinositol-3(PI)-phosphatase,which functionsas a negative regulator of the PIkinase(PI3K)*** well established that PTEN regulates the G1-S transitionby modulating the expression of cyclin D1 and *** passage of any cell through cell cycles is subtlymodulated by a series of proteins,among which the mainplayers in animal cells include cyclins,CDKs(cyclin-de-pendent kinases,positive regulators)and CDK inhibitors(negative regulators such as p2.and *** Dsare key regulators during the G1 phase and there are threetypes of cyclin Ds,D1,D2.and D3 in mammalian cells[3].Although the phenotypic analyses of single cyclin Dknockout mice revealed that each of the D type cyclinsis sufficient to drive normal development of the majority

关键词： PTEN,a general negative regulator of cyclin D expression

Cloning and characterization of cotton heteromeric acetyl-CoA carboxylase genes

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2007年第12期17卷 1412-1418页

作者： Qiao Zhixin and Liu Jinyuan(laboratory of Molecular Biology and Protein science laboratory of the Ministry of Education, department of biological sciences and biotechnology, tsinghua university, beijing 100084, china) laboratory of Molecular Biology and Protein science Department of Biological Sciences and Biotechnology Tsinghua University Beijing 100084 China

Heteromeric acetyl-coenzyme A (CoA) carboxylase (ACCase) catalyzes the formation of malonyl-CoA from acetyl-CoA. It plays an essential role in fatty acid synthesis in prokaryotes and most of plants. The heteromeric ACCase is composed of four subunits: biotin carboxylase (BC), biotin carboxyl carrier protein (BCCP), and α- and β-subunits of carboxyltransferase (α- and β-CT). In this study, we cloned five novel genes encoding the subunits of heteromeric ACCase (one BC, BCCP and β-CT, and two α-CTs) from cotton (Gossypium hirsutum cv. zhongmian 35) by RACE-PCR. The deduced amino acid sequence of these cDNAs shares high similarity with other reported heteromeric ACCase subunits. The phylogenetic analysis indicated that the different subunits of heteromeric ACCase were grouped in a similar pattern. Southern blot analysis revealed the milti-copy patterns of these heteromeric ACCase genes in cotton genome. Semi-quantitative RT-PCR demonstrated that heteromeric ACCase genes were constitutively expressed in all of the cotton tissues, but the transcripts accumulated at a relatively low level in roots. To our knowledge, this is the first report about characterization of the heteromeric ACCase genes in cotton.

关键词： heteromeric ACCase cotton gene cloning fatty acid synthesis.

Crystal Structure of the MH2.domain of Drosophila Mad

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china(Life sciences) 2009年第6期52卷 539-544页

作者： WANG Chong,CHEN Lei,WANG Le & WU JiaWei MOE key laboratory of Bioinformatics,{2. of biological sciences and biotechnology,tsinghua university,beijing 100084,china MOE key laboratory of Bioinformatics Department of Biological Sciences and Biotechnology Tsinghua University Beijing China

The decapentaplegic(Dpp),a member of the TGF-β superfamily,plays a pivotal role in the control of proliferation,global patterning and induction of specific cell fates during Drosophila *** against Dpp(Mad) is the founding member of the conserved Smad protein family which spe-cifically transduces the intracellular TGF-β signaling *** we report the 2.80 structure of the MH2.domain of Mad(Mad-MH2. that was readily superposed to the mammal Smad-MH2.*** unphosphorylated Mad-MH2.forms a symmetric homotrimer in crystals,consistent with the result of the size-exclusion chromatography that Mad-MH2.exhibited a propensity for concentration-dependent oligomerization prior to *** analysis revealed that the formation of homotrimeric Mad-MH2.is mainly mediated by contacts involving the extreme C-terminal SSVS motif,and is strengthened by phosphorylation of the last two Ser residues which was confirmed by the gel filtration analysis of the pseudophosphorylated Mad-MH2.DVD).Intriguingly,the homotrimer within an asymmetric unit only possesses two ordered C-terminal tails,reminiscent of the arrangement of the R-Smad/Smad4 complexes,indicating that the subunit with a flexible SSXS motif would be readily replaced by Co-Smad to form a functional heterotrimer.

关键词： TGF-β signaling Smad protein family MH2 domain crystal structure homotrimerization