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Metalloprotease MP100 was originally isolated as a beta-secretase candidate from human brain using a beta-amyloid precursor protein (beta-APP)-derived p-nitroanilide (pNA) peptide substrate. Peptide sequences from purified MP100 were now found to resemble sequences reported for a puromycin-sensitive aminopeptidase (PSA) highly enriched in brain, and cDNA cloning revealed nearly complete homology of MP100 to PSA, with only a single bp difference resulting in an amino acid change at position 184. Another MP100 cDNA encoded a protein with a 36-amino acid deletion (positions 180-217) and a two-amino acid insertion after Val533. Purified recombinant human MP100 cleaved the original pNA substrate as well as a free beta-site-spanning amyloid beta (A beta) peptide (A beta(-10/+10)), generating A beta(1-10). The latter substrate, however, remained uncleaved, if N- and C-terminally blocked, and also purified beta-APP was not cleaved. Double immunoimaging revealed partial, patchy, colocalization of beta-APP and MP100 in doubly transfected human embryonic kidney cells (HEK cells) and in normal neuroblastoma cells, and both proteins could be coimmunoprecipitated from rat brain extracts, suggesting their close vicinity in vivo. Coexpression of MP100 and beta-APP695, however, did not boost A beta levels in HEK cells, although active enzyme was produced. Thus, MP100 does not exert true beta-secretase-like function in cells, although it may well act as a secondary exoprotease in a complex beta-APP/A beta metabolism.  相似文献   

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The mouse dilute gene encodes a novel type of nonmuscle myosin that structurally combines elements from both nonmuscle myosin type I and nonmuscle myosin type II. Phenotypically, mutations in the mouse dilute gene result not only in the lightening of coat color, but also in the onset of severe neurological defects shortly after birth. This may indicate that the mouse dilute gene is important in maintaining the normal neuronal function in the mouse. We report the isolation and sequencing of "myoxin" (MYH12), the human homologue of the mouse dilute gene, and its assignment to human chromosome 15.  相似文献   

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A vesicle monoamine transporter was functionally identified, molecularly cloned, and characterized from a human substantia nigra cDNA library. The ATP-dependent transport of 5-[3H]hydroxytryptamine ([3H]5-HT) by digitonin-permeabilized fibroblasts expressing the vesicle monoamine/H± antiporter in culture exhibited a Km of 0.55 μM. Reserpine and tetrabenazine, inhibitors of two monoamine binding sites, effectively blocked [3H]5-HT accumulation with K1 values of 34 and 78 nM, respectively. Pretreatment of cells with as little as 10 nM reserpine in the presence of ATP abolished uptake. The rank order for substrate inhibition of [3H]5-HT uptake for both the previously reported rat vMAT1 and the human transporter clone followed the order 5-HT > dopamine > epinephrine > norepinephrine > 1 -methyl-4-phen- ylpyridinium > 2-phenylethylamine > histamine. The virtually identical transport characteristics of rvMATI and hvMAT1 confirm the relevance of neuropharmacological studies of rat brain biogenic amine uptake and storage to human brain neurochemistry.  相似文献   

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采用生物信息学工具预测与实验相结合的方法得到了一个新的小鼠分泌蛋白基因mBolA1。该基因定位于染色体3F2,cDNA全长为730bp,编码137个氨基酸的蛋白,该蛋白含有一个保守的BolA结构域,等电点为9.05。用RT-PCR方法从鼠的混合cDNA库中克隆到mBolA1。Western blot实验表明mBolA1能从瞬转的COS 7细胞中分泌到细胞培养液中。亚细胞定位显示mBolA1定位于细胞浆,且与高尔基体不共定位,提示它是个非经典分泌途径的分泌蛋白。RT PCR显示mBolA1在组织中广泛表达。它的具体功能有待进一步研究。  相似文献   

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Abstract: A protein target of mouse calcyclin, p30, which we call calcyclin-binding protein (CacyBP), was identified in mouse brain and Ehrlich ascites tumor (EAT) cells. The amino acid sequence of the CacyBP chymotryptic peptide was used to prepare synthetic oligonucleotides that served as a probe to screen the mouse brain cDNA library. A 1.4-kb positive clone was detected, isolated, and sequenced. The analyzed clone contains an open reading frame encoding a protein of a molecular mass of ~26 kDa. The nucleotide and predicted amino acid sequences indicate that CacyBP is a novel protein. The results obtained from northern blots show that the CacyBP gene is expressed predominantly in mouse brain and EAT cells. Using a pGEX vector the recombinant CacyBP was expressed in Escherichia coli, and its properties were analyzed. The recombinant protein interacts with calcyclin at a physiologically relevant range of Ca2+ in solution during affinity chromatography and on blots. Because CacyBP, like calcyclin, is present in the brain, the interaction of these two proteins might be involved in calcium signaling pathways in neuronal tissue.  相似文献   

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Cyclin-dependent kinase 5 (Cdk5) is predominantly expressed in neurons. In vitro, Cdk5 purified from the nervous tissue phosphorylates both high-molecular-weight neurofilament and microtubule-associated tau. The mouse gene encoding Cdk5 (Cdk5) was found to be 5 kb in length and divided into 12 exons. All of the exon-intron junctions matched the expected consensus sequence with the exception of the splice junction for intron 9, which has AT and AC dinucleotides instead of the usual GT and AG bordering sequence. In the 5′-flanking region of mouse Cdk5, several putative promoter elements were present, including AP1, Sp1, PuF, and TATA motifs. A metal regulatory element was also identified at position -207 to -201. Nucleotide sequence analysis of mouse Cdk5 showed high identity to the homologues of other vertebrate species, indicating that this kinase is highly conserved during evolution. Mouse Cdk5 was mapped to the centromeric region of mouse chromosome 5.  相似文献   

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利用电子克隆的方法寻找具有重要结构域的人类新基因ACBP5 ,根据得到的序列信息用RT PCR的方法获得全长基因 .通过生物信息学方法预测其结构 ,采用整体原位杂交和组织RT PCR的实验方法 ,在小鼠和鸡胚胎实验模型中研究该基因在发育过程中的表达情况 ,并对其功能进行初步的预测 ,获得一个含有乙酰辅酶A结合蛋白 (acyl CoAbindingprotein ,ACBP)结构域的人类新基因ACBP5 .ACBP5基因的cDNA长度为 10 83bp ,生物信息学方法预测其定位在人第 1号染色体上 ,包含 7个外显子 ,6个内含子 ,包含一个 35 4bp的完整阅读框架 ,编码一个 118个氨基酸残基的蛋白 .在以小鼠胚胎和鸡胚为模型的整体原位杂交中 ,以ACBP5基因全长编码区为探针的结果均显示该基因在胚胎头部特异表达 ,并且主要集中在中脑与间脑之间的峡部 .成体小鼠的组织RT PCR的结果显示 ,ACBP5的同源基因在各组织中均有表达 .这提示ACBP5基因在不同物种中的表达可能比较保守 ,并与头部发育有密切关系 ,同时也对维持细胞的正常功能起到重要的作用 .  相似文献   

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By searching the Expressed Sequence Tag database, a full-length cDNA for a novel human CC chemokine was cloned. This cDNA encoded a 94-amino-acid protein with a putative signal peptide of 26 amino acids. The deduced mature protein had the four conserved cysteine residues characteristic of CC chemokines and showed 44% identity with MIP-1beta and 40% identity with MIP-1alpha, RANTES, and MCP-4. mRNA for this chemokine was expressed constitutively in human heart and liver and with lesser but detectable levels in skeletal muscle, kidney, and small intestine. To investigate its biological activity, the protein was expressed in mammalian cells and purified by affinity chromatography. The recombinant protein demonstrated chemotactic activity in vitro for T cells and monocytes but not for neutrophils. The gene was mapped to chromosome 7q11.2 by fluorescence in situ hybridization. Based on its structural identity with other CC chemokines and the chemotactic activity and chromosomal location of this chemokine, we designate this chemokine small inducible cytokine subfamily A, member 26 (SCYA26). This gene symbol has been approved by the HUGO Gene Nomenclature Committee.  相似文献   

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Zhu  Mei Hong  Lee  Young Mee  Jin  Nange  So  Insuk  Kim  Ki Whan 《Neurophysiology》2003,35(3-4):302-307
The transient receptor potential protein homologue TRPC5 was reported as a molecular identity for the muscarinic receptor-activated nonselective cationic channel (NSCC) in the murine stomach smooth muscle. The canonical, or classical, transient receptor potential proteins, TRPC4 and TRPC5, were suggested as members of the same subfamily of TRPC channels and to be coexpressed as a heteromultimer of both TRPC as well as a homotetramer of each TRPC protein. Thus, we investigated whether the TRPC4 channel is also responsible for the NSCC activated by acetylcholine (ACh) or carbachol (CCh) using electrophysiological techniques. The TRPC channels were expressed in HEK293 cells. When murine TRPC4 channels (mTRPC4) were expressed, the current–voltage relationship of mTRPC4 was also similar to that recorded in native murine gastric myocytes or mTRPC5-expressing HEK cells. With 0.2 mM GTPγS in the pipette solution, the currents in mTRPC4-expressing cells were activated transiently like those in NSCC in the murine stomach and the expressed mTRPC5. The currents recorded in mTRPC4-expressing cells were inhibited by 1 mM La3+ and 100 μM flufenamate. The currents recorded in mTRPC4-expressing cells depended on the extracellular calcium concentration. From the above results, we suggest that mTRPC4/5 might be candidates for the NSCC activated by ACh or CCh in the murine stomach.  相似文献   

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用基因组步行法 (genomewalker)克隆了人A33抗原基因的 5′调控区 94 0bp片段 ,并用PCR法鉴定了这一克隆的正确性 .将该序列提交GenBank ,登录号为AF2 0 0 6 2 6 .用引物延伸法 (primerex tension)确定了A33基因的转录起始位点 ,发现该位点位于一个TATA盒下游 10个碱基处 .以增强型绿色荧光蛋白为报告基因构建了不同长度的A33启动子 5′缺失载体 ,用脂质体介导的方法将这些载体转染LoVo、HeLa、2 93等细胞 ,比较了EGFP的表达水平 .研究发现 ,A33启动子上主要转录调控元件以及与组织特异性表达相关的转录调控元件位于A33启动子的 - 10 4~ + 2 5bp区域  相似文献   

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Liu  Zhaowei  Du  Zhanqiang  Li  Kai  Han  Yangguang  Ren  Guogang  Yang  Zhuo 《Neurochemical research》2020,45(7):1602-1613
Neurochemical Research - Recently, possible applications of zinc oxide nanoparticles (nano-ZnO) have been extensively studied owing to their ease of synthesis. However, the effect of nano-ZnO on...  相似文献   

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《Genomics》1995,29(3)
The humanCBFA2T1(also known asMTG8) gene, on chromosome 8, has been identified through its involvement in the t(8;21) chromosomal translocation, frequently found in acute myeloid leukemia. We report here the isolation and characterization of the mouse homologue of theCBFA2T1gene,Cbfa2t1h.Nucleotide sequence analysis ofCbfa2t1hcDNA clones revealed an open reading frame encoding a protein of 577 amino acids with an extremely high degree of amino acid identity (99.3%) to the human protein. The nucleotide sequence is also highly conserved between mouse and human in the 5′- and 3′-untranslated regions (87.0, 92.0, and 93.7% identities for 5′-untranslated, coding, 3′-untranslated regions, respectively). The 3′-untranslated region ofCbfa2t1hcontains a (CA)ndinucleotide repeat, and the polymerase chain reaction amplification of the (CA)nrepeat region revealed fragment length polymorphism among mouse strains. Using this polymorphism, we have mappedCbfa2t1hto mouse chromosome 4 close to the centromere using SMXA recombinant inbred strains and 106 intersubspecific backcross progenies of the (DBA/2 × Mae) × Mae cross. The chromosomal location was also confirmed by fluorescencein situhybridization.  相似文献   

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以枳[Poncirus trifoliata(L.)Raf.]实生苗为材料,采用RT-PCR及RACE技术,获得了PPF-1(开花、衰老相关基因)同源基因的cDNA全长序列PtPPF-1,该cDNA全长1 493 bp,编码452个氨基酸,与豌豆PPF-1、拟南芥ALB3、水稻PPF-1及葡萄一未命名基因的氨基酸序列同源性较高,说明PPF-1基因在进化过程中可能变异较小。半定量RT-PCR分析表明PtPPF-1在叶片中表达量最高,顶芽和茎中相似,在根中未检测到,表明该基因功能与叶绿体有关。  相似文献   

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用同源筛选方法,从水稻 (Oryza sativa L.) 基因组文库中分离到一个与人类肿瘤抑制基因QM具有同源性的基因,命名为OSQM1.该基因包括4个外显子和3个内含子,编码219个氨基酸,其中有46个碱性氨基酸,其等电点高达11.02.同源性搜寻发现此基因存在于真核生物中而且保守性较强,表明它可能具有重要的作用.Northern分析结果表明,它在不同的水稻器官中都有表达,但在花和愈伤组织中的表达水平明显低于其他营养器官.它在根和叶中的表达水平受环境因素的影响.  相似文献   

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用同源筛选方法 ,从水稻 (OryzasativaL .)基因组文库中分离到一个与人类肿瘤抑制基因QM具有同源性的基因 ,命名为OSQM1。该基因包括 4个外显子和 3个内含子 ,编码 2 19个氨基酸 ,其中有 4 6个碱性氨基酸 ,其等电点高达 11.0 2。同源性搜寻发现此基因存在于真核生物中而且保守性较强 ,表明它可能具有重要的作用。North ern分析结果表明 ,它在不同的水稻器官中都有表达 ,但在花和愈伤组织中的表达水平明显低于其他营养器官。它在根和叶中的表达水平受环境因素的影响。  相似文献   

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