里氏木霉纤维二糖酶bg1Ⅱ基因的cDNA克隆及其在大肠杆菌中的表达

将里氏木霉总RNA反转录得到cDNA第一链，并以之为模板进行RT－PCR合成约1．4kb的纤维二糖酶基因cDNA,将所得的cDNA经测序后克隆到温度敏感型载体pJW2中，经PCR和双酶切鉴定筛出阳性重组子，温度诱导后，经酶活测定，bg1Ⅱ基因在大肠杆菌中得到了表达，酶活为0．75IU／mL。     

喉癌相关基因LCRG1的克隆和表达分析

喉癌是严重危害人类健康的一类恶性肿瘤。选用在mRNA差异显示研究中获得的在喉癌组织中表达显著下调且代表新基因的EST之一（AF10056）,设计引物进行cDNA文库筛选,得到一全长为3448bp的cDNA序列,其开放读码框编码288个氨基酸,与已知蛋白质无明显同源性,属一新发现的基因,GenBank接受号为AF268387。与GenBank数据库匹配分析,发现该基因包含6个外子,基因组RT－PCR显示有40％（12／30）的喉癌组织表达下调,RT－PCR显示有54．5％（6／11）其他肿瘤细胞系表达缺失。把该基因命名为喉癌相关基因（laryngeal carcinoma related gene1,LCRG1)。这提示LCRG1可能与喉癌的发生发展相关。     

MES23.5细胞酪氨酸羟化酶的种属来源及其重组酶的活性测定

MES 2 3 5细胞作为研究神经变性疾病的工具 ,是一种杂交瘤性多巴胺能神经元细胞系 ,由大鼠胚胎中脑细胞与小鼠神经母细胞瘤 胶质瘤细胞系N18TG2杂交而成 .其酪氨酸羟化酶 (tyrosinehydroxylase ,TH)的动物种属来源不清楚 .应用反转录聚合酶链反应 (RT PCR)法从MES 2 3 5细胞系中克隆了编码TH的cDNA ;结构分析表明 ,其cDNA编码区由 14 97碱基构成 ,共编码 4 98个氨基酸 ,与大鼠和小鼠TH的同源程度分别为 93%和 10 0 % .该杂交瘤细胞系表达小鼠TH .将该cDNA亚克隆至原核表达载体pGEX 4T 1,经原核细胞表达、亲和层析得到了电泳纯的基因重组小鼠TH(recombinantmousetyrosinehydroxylase ,rmTH) .改良和建立了一种体外分析TH活性的新方法 .活性分析证明 ,纯化的rmTH能催化L 酪氨酸发生加单氧反应生成L 3,4 二羟基苯丙氨酸 (L 多巴 ) .rmTH的表观分子量为 5 6kD ;其酶促加单氧反应的最适pH值为 7 0 .乙二胺四乙酸能显著抑制此酶的活性 ,而亚铁离子能明显增强其活性 .     

鼻咽癌上皮细胞株HNE1差异表达基因的分离与鉴定

为了分离鼻咽癌差异表达基因 ,应用抑制性扣除杂交技术 ,在正向抑制性扣除杂交中 ,以鼻咽癌上皮细胞株HNE1cDNA作为检测子 ,以人胚鼻咽上皮细胞cDNA作为驱赶子 ;在反向抑制性扣除杂交中 ,以人胚鼻咽上皮细胞cDNA作为检测子 ,以鼻咽癌上皮细胞株HNE1cDNA作为驱赶子 ,分别通过抑制性扣除杂交 ,构建了鼻咽癌上皮细胞株HNE1表达下调和表达上调的两个扣除cDNA文库 .从鼻咽癌相关的扣除cDNA文库中随机挑取 1 2 0 0个克隆 ,采用菌落PCR扩增其插入cDNA片段 ,自动点膜制备成cDNA微阵列膜 ,分别用鼻咽癌上皮细胞株HNE1、人胚鼻咽上皮mRNA经逆转录标记cDNA探针 ,分别与cDNA微阵列膜杂交 ,通过杂交信号的自动扫描分析 ,对杂交信号存在 5倍差异的克隆进行测序 ,获得了 1 0个鼻咽癌差异表达基因的cDNA片段 ,其中 3个为新基因序列 ,其GenBank登录号为 :AF5 1 0 1 88、AF5 1 0 1 89和AF5 1 0 1 90 ,7个代表已知基因序列 .采用RT PCR证实S1 0 0A8,CK1 9和RBP1基因在人胚鼻咽上皮中高表达而在鼻咽癌细胞株HNE1中低表达 .这些结果显示上述基因可能是鼻咽癌发生的重要因素     

棉花GhCCR1基因结构及表达分析

根据棉花GhCCR1基因的cDNA序列设计引物,采用PCR技术从棉花中克隆了GhCCR1基因的DNA序列,并采用半定量RT-PCR方法分析了GhCCR1基因在不同发育阶段棉纤维中的表达情况.结果表明:GhCCR1编码区DNA序列长度为1 161 bp,包含4个外显子和3个内含子,内含子富含AT,所有外显子/内含子交接点都遵从gt/ag剪接规则.半定量RT-PCR检测表明,GhCCR1基因在不同发育阶段的棉纤维中均有表达,在开花后20 d的棉纤维中表达量最高,说明该基因可能参与调控棉纤维细胞的伸长和次生壁的增厚过程.     

AQP1真核表达载体的构建及其在FRT细胞的表达

目的：构建小鼠AQP1基因真核表达质粒并观察其在FRT细胞中的表达。方法：采用RT—PCR方法从小鼠肾脏组织的总cDNA中扩增出小鼠的AQP1基因,采用基因重组技术将AQP1的cDNA片段插入真核表达载体pCAGGS,构建小鼠AQP1的真核表达质粒,脂质体转染FRT细胞进行表达。结果：酶切和测序结果证实AQP1真核表达质粒构建成功,经脂质体转染FRT细胞后,免疫荧光检测证明AQPI蛋白在真核细胞中成功表达。结论：成功构建真核表达质粒pCAGGS—AQP1-myc,并在FRT细胞中得以表达。为进一步研究小鼠AQP1过表达时的功能及机制奠定了实验基础。     

黑鲷DMRT1基因cDNA的克隆、组织表达谱及在性别逆转前后性腺中的表达

利用RT—PCR和3′-RACE的方法从黑鲷精巢中克隆丁DMRT1基因cDNA的部分序列。组织特异性表达分析表明DMRT1基因只在精巢中表达,半定量RT—PCR检测显示DMRT1基因在性别逆转前、性别逆转期和性别逆转后的精巢中的表达量无显著差异,在鱼类成体的精巢中,DMRT1的表达量可能不会因精巢结构或生理状态的改变而发生改变,而始终维持一定量的表达。     

小鼠PC-1基因在大肠杆菌中的表达和纯化

利用PCR和基因重组技术构建了小嫌PC－1基因全长cDNA及其N端45个氨基酸残基的表达质粒pGEX-4T-1-mPC-1和pGEX-4T-1-mPC-1-45。经IPTG诱导后,在大肠杆菌DH5α中,GST－mPC-1和GST－mPC-1-45两个融合蛋白都获得了可溶性高表达。经谷胱甘肽Sepharose-4B亲和柱层析纯化后,获得了纯的GST－mPC-1和GST－mPC-1-45蛋白。     

人牛精浆蛋白相关新基因的cDNA克隆、定位和表达

为了研究牛精浆 (bovineseminalplasma ,BSP)蛋白及其相关蛋白在受精及受精卵发育中的重要作用 ,寻找BSP蛋白相关新基因 .采用cDNA末端快速扩增 (RACE)技术 ,克隆了一个BSP蛋白相关基因的cDNA序列 .应用辐射杂种细胞系 (RH)技术进行了基因染色体定位 .通过RT PCR检测了该基因在人体各组织中的表达情况 .并将该基因编码的蛋白进行了原核表达 .新基因的cDNA长度为 10 5 2bp ,其开放阅读框架 (ORF)编码了一个含 2 2 3个氨基酸残基的蛋白质 ,氨基酸序列中含有 4个纤连蛋白Ⅱ结构域 ,与BSP蛋白在结构上具有一定的相似性 ,称其为人BSP相关蛋白 (humanBSP relatedproteins ,HBRP) .该基因定位于染色体 19q13,在大肠杆菌中表达为 5 2kD的融合蛋白 .研究结果提示 ,应用RACE方法克隆了一种新的人类与BSP蛋白相关的基因 ,推测其编码蛋白是与BSP蛋白功能相关的结合蛋白 ,通过基因重组技术大量获得表达蛋白 ,对进一步研究新蛋白的生物学功能具有重要的意义 .     

IL-1β的基因克隆及在原核中的表达

从人外周血中分离出白细胞,提取其总RNA,根据文献报道的IL－1β的核苷酸序列合成5’和3’端引物,用RT－PCR的方法获得了IL－1β的基因cDNA,并在大肠肝菌中获得了高效表达,表达量占全菌的40％,并对表达产物进行了分离纯化和活性分析,获得了纯度大于98％的样品,该样品表现出明显的生物学活性。     

Expression of Endothelin-Converting Enzyme in Both Neuroblastoma and Glial Cell Lines and Its Localization in Rat Hippocampus

Abstract: Endothelin-converting enzyme is a phosphoramidon-sensitive metalloprotease that cleaves big endothelin to the potent vasoconstrictor peptide, endothelin. The converting enzyme is expressed in endothelial cells in a variety of tissues and in some secretory cells. In the present study, phosphoramidon-sensitive endothelin-converting enzyme activity has been demonstrated by radioimmunoassay in the neuroblastoma cell line, SH-SY5Y, and in Bu17 and C6 glioma lines. The identity of the activity was confirmed by immunoblotting, revealing a polypeptide of ∼120 kDa in each of these lines, in D384 glioma cells, and in primary astrocytes. Immunofluorescence revealed the cell-surface location of endothelin-converting enzyme in the neuronal and glial cell lines and in primary astrocytes. Pretreatment of SH-SY5Y and Bu17 cells with phosphoramidon resulted in an apparent concentration of the enzyme protein in an intracellular compartment. Immunoperoxidase-staining of rat brain sections located this metalloprotease to the pyramidal cells of the hippocampus. Endothelin-converting enzyme-1 was revealed by in situ hybridisation in the neuronal and glial cell lines.     

Endogenous expression of nNOS protein in several neuronal cell lines

Several neuronal cell lines were screened for endogenous expression of neuronal nitric oxide synthase (nNOS) protein using Western blot analysis. Detectable levels of the nNOS protein were evident in the SK-N-SH, SH-SY5Y, and N1E-115 neuroblastoma cell lines, as well as the NG108-15 neuroblastoma x glioma hybrid. Only trace amounts were visible in Neuro2A human neuroblastoma cells. The presence of endogenously expressed nNOS in these cells may allow for the study of the interaction between nNOS and the endogenous receptor systems expressed in the same cells.     

Identification of the RA response element and transcriptional silencer in human <Emphasis Type="Italic">αCaMKII</Emphasis> promoter

The promoter of alpha subunit of the rat calcium/calmodulin-dependent protein kinase II (alphaCaMKII) gene was identified to contain an essential TATA element. Cell-based functional assay showed that the rat promoter displayed greater activity in neuronal cells than in non-neuronal cells. To characterize the human alphaCaMKII promoter, we have developed a promoter-reporter gene assay using different cell lines. A 2047 base pairs (bp) human alphaCaMKII gene promoter was cloned from human genomic DNA. Unlike the rat alphaCaMKII promoter, DNA sequence analysis showed that the human promoter was devoid of TATA element. We made series deletions of the promoter and fused the different sizes of the human promoter sequences to a luciferase reporter gene. The promoter-reporter constructs were transfected into human neuroblastoma SH-SY5Y, human neuroblastoma BE(2)-M17, and rat pheochromocytoma PC12 neuronal cell lines as well as human embryonic kidney HEK293 and human glioma U251 non-neuronal cell lines. The reporter gene assay demonstrated that the human alphaCaMKII promoter displayed high activity in the neuronal cell lines, while the activity was low in non-neuronal cell lines. All-trans retinoic acid (RA) enhanced the promoter activity in SH-SY5Y cells. Further analysis showed that there were two RA response elements located between +11 and +136 and -1911 to -593. In addition, we have identified a potent silencer at position -179 to -244 of the human alphaCaMKII promoter.     

EphA2对神经胶质瘤细胞系U251的凋亡﹑增殖﹑迁移和侵袭的研究

为了研究EphA2对神经胶质瘤细胞系U251在增殖、凋亡、迁移和侵袭方面所起的作用,用RT-PCR方法检测正常脑组织标本与两种恶性胶质瘤细胞系中EphA2 mRNA表达水平,然后用化学合成的针对EphA2基因的小干扰RNA(siRNA)下调该基因的表达,以检测其在U251中的生物学功能．证实了EphA2基因在正常脑组织标本中的表达水平远低于两种恶性胶质瘤细胞系．把体外化学合成针对EphA2基因的小干扰RNA(siRNA- EphA2)转染入U251细胞后,Western blot, 实时定量 RT-PCR检测到U251细胞中EphA2蛋白及mRNA表达水平都明显降低,并且细胞增殖受到显著抑制,同时出现了明显的细胞凋亡．伤口愈合实验(检测细胞迁移能力),Transwell小室实验(检测细胞侵袭能力)均表明,下调EphA2的表达后,细胞的迁移和侵袭能力较阴性对照组显著减弱．上述结果表明,在神经胶质瘤U251细胞中,EphA2与其恶性增殖及高度侵染性相关,可作为分子治疗的有效靶点．     

The expression and activity of cystathionine-γ-lyase and 3-mercaptopyruvate sulfurtransferase in human neoplastic cell lines

The expression and activity of cystathionine γ-lyase (CST) and 3-mercaptopyruvate sulfurtransferase (MPST) were investigated in the human neoplastic cells lines: astrocytoma U373, neuroblastoma SH-SY5Y, melanoma A375, and melanoma WM35. Gene expression analysis demonstrated that the investigated neoplastic cells showed the expression of MPST and what is particularly interesting, the expression of CST. The presence of CST in these cells was confirmed using RT-PCR and western blot analysis. However, in U373 cells, a very low activity of CST was detected. In all the investigated cell lines, the activity of MPST was higher than that of CST, which suggests that in these cells, the main pathway of sulfane sulfur formation is the MPST-catalyzed reaction. RP-HPLC analysis showed a large disparity between the level of cystathionine and GSH in the investigated neoplastic cells. In SH-SY5Y cells, the low level of GSH and low GSH/GSSG ratio corresponded with the highest CST activity. Further investigations could aim at verifying whether the stimulation of CST, at the level of protein or gene expression, could change the proliferation of neoplastic cells.     

稳定表达人Eps8基因的胶质瘤U251细胞系的建立

应用亚克隆方法构建pEGFP-C3／Eps8真核表达载体,经测序鉴定后,用脂质体进行胶质瘤U251细胞的转染,应用G418筛选出稳定表达pEGFP-C3／Eps8和pEGFP—C3的细胞系,最后通过Western blot和荧光定位证明印娼在U251细胞中过量表达。本实验成功建立了稳定转染Eps8的U251细胞系,为进一步研究Eps8基因在胶质瘤中的功能奠定了良好的实验基础。     

Hypoxia-induced erythropoietin expression in human neuroblastoma requires a methylation free HIF-1 binding site

The glycoprotein hormone Erythropoietin (EPO) stimulates red cell production and maturation. EPO is produced by the kidneys and the fetal liver in response to hypoxia (HOX). Recently, EPO expression has also been observed in the central nervous system where it may be neuroprotective. It remained unclear, however, whether EPO is expressed in the peripheral nervous system and, if so, whether a neuronal phenotype is required for its regulation. Herein, we report that EPO expression was induced by HOX and a HOX mimetic in two cell lines derived from neuroblastoma (NB), a tumor of the peripheral nervous system. Both cell lines with inducible EPO expression, SH-SY5Y and Kelly cells, expressed typical neuronal markers like neuropeptide Y (NPY), growth-associated protein-43 (GAP-43), and neuron-specific enolase (ENO). NB cells with a more epithelial phenotype like SH-SHEP and LAN-5 did not show HOX inducible EPO gene regulation. Still, oxygen sensing and up-regulation of hypoxia-inducible factor-1 (HIF-1) were intact in all cell lines. We found that CpG methylation of the HIF binding site (HBS) in the EPO gene 3' enhancer was only present in the SH-SHEP and LAN-5 cells but not in SH-SY5Y and Kelly cells with regulated EPO expression. The addition of recombinant EPO to all NB cells, both under normoxic and hypoxic conditions, had no effect on cell proliferation. We conclude that the ability to respond to HOX with an increase in EPO expression in human NB may depend on CpG methylation and the differentiation status of these embryonic tumor cells but does not affect the proliferative characteristics of the cells.     

Expression of c-src in cultured human neuroblastoma and small-cell lung carcinoma cell lines correlates with neurocrine differentiation.

Human cell lines with neuronal and neuroendocrine features were examined for their expression of pp60c-src, the cellular homolog of the transforming gene product pp60v-src of Rous sarcoma virus. Four neuroblastoma (LA-N-5, SH-SY5Y, Paju, and SK-N-MC) and three small-cell lung carcinoma (U-2020, U-1690, and U-1285) cell lines were selected on the basis of their stage of neurocrine differentiation, as determined by the expression of neuron-specific enolase. In an immune complex protein kinase assay, all seven cell lines displayed c-src kinase activity which was considerably higher than that found in nonneurocrine cells (human diploid fibroblasts, glioma, and non-small cell lung carcinoma cell lines). Furthermore, the c-src kinase activity, as determined by autophosphorylation or phosphorylation of an exogenous substrate, enolase, correlated with the stage of neurocrine differentiation. There was an approximately 30-fold difference in c-src kinase autophosphorylation activity between the cell lines representing the highest and lowest stages of neurocrine differentiation. A similar variation was found in the steady-state levels of the c-src protein of these cell lines. Highly differentiated neuroblastoma cells expressed two forms of the src protein. Digestion by Staphylococcus aureus V8 protease did reveal structural diversity in the amino-terminal ends of these c-src molecules. In summary, we found a clear correlation between c-src kinase activity and the stage of neuronal and neuroendocrine differentiation. Thus, the phenotypic similarity between neurons and neuroendocrine cells includes high c-src expression.     

PXR激活在拮抗SH-SY5Y细胞凋亡中的作用

人神经母细胞瘤细胞SH-SY5Y细胞可以表达神经元特异性的酪氨酸羟化酶、多巴胺-β-羟化酶以及多巴胺转运体等,因此可用于建立帕金森病的体外模型。虽然帕金森综合症发病的确切机制至今尚不清楚,但众多的病理学资料证实该病患者存在中脑黑质多巴胺能神经元的凋亡。自由基、兴奋性