Adenovirus-Mediated Inducible Gene Expression in Vivo by a Hybrid Ecdysone Receptor

Precise control of transgene expression would markedly facilitate certain applications of gene therapy. To regulate expression of a transferred gene in response to an exogenous compound in vivo, we modified the ecdysone-responsive system. We combined the advantages of the Drosophila (DmEcR) and the Bombyx ecdysone receptor (BmEcR) by creating a chimeric Drosophila/Bombyx ecdysone receptor (DB–EcR) that preserved the ability to bind to the modified ecdysone promoter without exogenous retinoid X receptor (RXR). In cultured cells, DB–EcR effectively mediates ligand-dependent transactivation of a reporter gene at lower concentrations of the chemical ecdysone agonist GS-E than VgRXR (DmEcR + RXR). Transgene delivery in vivo was achieved by intramyocardial injection of recombinant adenovirus vectors in adult rats. Upon stimulation with GS-E, DB–EcR potently (>40-fold induction) activated gene expression in vivo while VgRXR was not induced. This hybrid ecdysone receptor represents an important new tool for in vivo transgene regulation with potentially diverse applications in somatic and germline transfer.     

Characterization of ecdysteroid biosynthesis in the pond wolf spider,Pardosa pseudoannulata

Ecdysteroids, as the key growth hormones, regulate moulting, metamorphosis and reproduction in arthropods. Ecdysteroid biosynthesis is catalysed by a series of cytochrome P450 monooxygenases (CYP450s) encoded by Halloween genes, including spook (spo), phantom (phm), disembodied (dib), shadow (sad) and shade (shd). The ecdysteroid biosynthesis in insects is clear with 20-hydroxyecdysone (20E) as the main ecdysteroid. However, the information on the major ecdysteroids in arachnids is limited. In this study, Halloween genes spo, dib, sad and shd, but not phm, were identified in the pond wolf spider, Pardosa pseudoannulata. Phylogenetic analysis grouped arachnid and insect Halloween gene products into two CYP450 clades, the CYP2 clan (spo and phm) and the mitochondrial clan (dib, sad, and shd). In P. pseudoannulata, the temporal expression profile of the four Halloween genes in concurrence with spiderling moulting with steady increase in the course of the 2nd instar followed by a rapid dropdown once moulting was completed. Spatially, the four Halloween genes were highly expressed in spiderling abdomen and in the ovaries of female adults. In parallel, ponasterone A (PA), but not 20E, was detected by LC–MS/MS analysis in P. pseudoannulata, and it was demonstrated as a functional ecdysteroid in the spider by accelerating of moulting with PA addition. The present study revealed the different ecdysteroid biosynthesis pathways in spiders and insects.     

脊髓损伤后细胞凋亡及iNOS的表达

目的研究大鼠脊髓损伤后细胞凋亡的特点与诱生型一氧化氮合酶 (induciblenitricoxidesynthase,iNOS)的表达规律以及两者之间的关系。方法成年SD大鼠随机分为 3组 ,分别造成轻、中、重度脊髓急性损伤模型 ,于损伤后不同时间点 (4h、8h、1d、3d、7d、1 4d、2 1d)处死。用HE染色观察损伤脊髓组织病理变化 ,用免疫组化染色检测iNOS、Bax阳性细胞 ,TUNEL法标记凋亡细胞。结果HE染色镜检发现脊髓组织病理学改变随着损伤程度的增加而加重。免疫组化结果显示正常对照组及单纯椎板切除组神经元、神经胶质细胞、室管膜细胞、血管内皮细胞极少量表达iNOS ;损伤后 8小时上述细胞iNOS表达增加 ,7天达高峰 ,1 4天仍较明显 ,2 1天降低。Bax表达及TUNEL标记阳性细胞的时间分布特点与iNOS相似 ,7天达高峰 ,阳性细胞以白质中胶质细胞为主。iNOS表达与脊髓损伤程度及神经细胞凋亡指数间存在正相关 (r=0 41 4 ,P <0 0 1 ;r=0 854 ,P <0 0 1 )。结论大鼠脊髓损伤后iNOS和Bax表达增强 ,凋亡神经细胞大量出现。iNOS表达与脊髓原发损伤程度及损伤后神经细胞凋亡指数间存在正相关     

The hsp27 gene of the Mediterranean fruit fly,Ceratitis capitata: structural characterization,regulation and developmental expression

In the present study, a genomic DNA clone encoding the medfly homolog of Drosophila melanogaster hsp27 gene, named Cchsp27, was isolated. We sequenced a part of the clone containing the coding region, the 5′ untranslated region and approximately 2.8 Kb of the 5′ flanking region of the gene. Phylogenetic analysis of several insect small heat shock proteins, suggested that CcHsp27 is orthologous to Drosophila Hsp27 and Sarcophaga crassipalpis Hsp25. The Cchsp27 gene was mapped at the 81A division of the sixth chromosome which coincides with one of the major heat shock puffs of medfly. Structural analysis of the 5′ flanking region of the Cchsp27 gene revealed the presence of five putative heat shock elements and one putative ecdysone response element. In addition to heat induction, the Cchsp27 gene was expressed at several stages of normal medfly development. In general, the developmental expression pattern of the Cchsp27 gene was similar to the respective pattern of Drosophila hsp27 gene. However, there were some important differences in certain developmental stages suggesting differential regulation of the hsp27 gene in the two dipterans species. Salivary gland culture experiments showed that the Cchsp27 gene is regulated by 20‐hydroxyecdysone.     

高效表达型T克隆载体的构建及其特性

目的研制高效表达型T载体用于基因的表达及蛋白功能分析。方法限制性内切酶EcoR V酶切真核表达载体peDNA3,回收线性化质粒片段与三磷酸胸腺嘧啶脱氧核苷酸（driP）70℃退火,构成T克隆载体并回收纯化。将增强绿色荧光蛋白基因（EGFP）和中国旱獭α干扰素基因（cwIFNA5）分别扩增后直接克隆到新构建的表达型T载体,转化感受态细菌,挑选阳性菌并制备质粒瞬时转染真核细胞,荧光显微镜观察EGFP的表达,病毒保护试验检测中国旱獭α干扰素的生物学活性。结果成功构建了表达型T载体,外源基因EGFP和cwIFNA5克隆进该载体后可以进行高效表达,基因转染72h后,荧光显微镜观察到EGFP基因转染细胞荧光阳性率在80％以上,荧光强度高;病毒保护试验表明cwIFINA5基因转染细胞培养上清干扰素效价达1：640。结论新构建的表达型T载体可用于基因的克隆之外,还可以直接用于基因的高效表达及蛋白质功能分析。     

牛珀至宝微丸对蛋白激酶C调控内毒素诱导iNOS基因表达的影响

目的 :探讨牛珀至宝微丸对蛋白激酶 C(PKC)调控 (L PS)诱导单核巨噬细胞诱导型一氧化氮合酶(i NOS)基因表达的影响。方法 :用 PKC活性测定法观察 L PS对 PKC的激活作用 ,用 Griess还原法测定一氧化氮 (NO)的生成 ,用基因重组技术构建 i NOS荧光素酶报告基因载体 ,用基因转染及报告基因检测等方法研究牛珀至宝微丸调控 L PS刺激 RAW2 6 4 .7细胞对 i NOS启动子活性的诱导作用及其与 PKC的关系。结果 :牛珀至宝微丸可负调节 L PS刺激 RAW2 6 4 .7细胞引起的 PKC磷酸化激活和膜移位 ,并可延长 PKC抑制剂 H 7下调 NO作用时间。荧光素酶报告基因实验结果显示 ,牛珀至宝微丸可抑制 L PS刺激诱导的 i NOS启动子的转录活性 ,并可增强 H 7和钙离子通道阻滞剂维拉帕米的作用。结论 :牛珀至宝微丸抑制 L PS刺激 RAW2 6 4 .7细胞所致的 NO生成增加 ,其机制之一是量效与时间两方面抑制 PKC激活和细胞内钙增加 ,从而影响 i NOS启动子的转录活性     

Identification of ecdysteroidogenic enzyme genes and their expression during pupal diapause in the cabbage armyworm,Mamestra brassicae

In this study, we identified ecdysteroidogenic enzymes in the cabbage armyworm, Mamestra brassicae, and demonstrated reduced expression of these genes during diapause. Some insects employ a temporary developmental arrest, diapause, to survive in severe environments. The titres of the moulting hormone ecdysteroid were reduced in diapause pupae of M. brassicae; therefore, ecdysteroidogenesis might be suppressed by a diapause‐specific mechanism. To clarify expression changes of ecdysteroidogenic enzyme genes during diapause in M. brassicae, we first identified the genes for seven ecdysteroidogenic enzymes: Neverland, Non‐molting glossy (Nm‐g), CYP307A1 (Spook), CYP306A1 (Phantom), CYP302A1 (Disembodied), CYP315A1 (Shadow) and CYP314A1 (Shade). Enzymatic assays using heterologous expression in Drosophila Schneider 2 (S2) cells and analysis of mRNA distribution indicated that the identified genes were ecdysteroidogenic enzymes of M. brassicae. Expression levels of these ecdysteroidogenic enzyme genes were compared between prothoracic glands in different pupal stages throughout diapause. Immediately after pupation, diapause‐destined pupae showed similar expression levels of ecdysteroidogenic enzyme genes to those of nondiapause pupae. All of these genes showed reduced gene expression after diapause initiation. Expression was immediately increased in diapause‐destined pupae at the postdiapause quiescence phase. These results indicate that reduced expression of ecdysteroidogenic enzyme genes suppresses ecdysteroidogenesis and maintains developmental arrest during diapause.     

sTRAIL真核表达载体的构建及其对C6胶质瘤细胞增殖影响的体外实验研究

目的构建重组基因表达载体PcDNA-sTRAIL并观察其对C6胶质瘤细胞的抑制作用。方法通过PCR扩增和定向克隆技术构建重组真核表达载体PcDNA-sTRAIL。以阳离子脂质体介导转染C6胶质瘤细胞并用流式细胞仪观测对细胞增殖的影响。结果经过测序鉴定和蛋白表达检测证实,重组真核表达载体PcDNA-sTRAIL构建成功。阳离子脂质体介导质粒转染C6胶质瘤细胞阳性率达50%。脂质体PcDNA-sTRAIL转染C6细胞后,相比未转染、空质粒转染、Lipofectin转染组C6胶质瘤细胞增殖抑制、细胞凋亡明显增加（t分别=9.52、7.20、2.84,P均〈0.05）。结论成功构建了sTRAIL基因的真核表达载体,并从体外实验中初步证实了其对C6胶质瘤细胞增殖具有明显的抑制作用。     

截短型小鼠成纤维细胞生长因子受体-1基因慢病毒载体构建及在真核细胞中的表达

本研究旨在克隆小鼠成纤维细胞生长因子受体1(fibroblast growth factor receptor 1,fgfr1)基因,构建携带增强型绿色荧光蛋白(EGFP)的截短型fgfr1(△fgfr1)重组慢病毒载体并在真核细胞中表达。采用逆转录-聚合酶链反应(RT-PCR)以BALB/c胎鼠脑组织为模板克隆全长型fgfr1基因,连接至克隆载体pCR-Blunt,通过反向PCR技术删除胞内磷酸化区域获得△fgfr1,限制性内切酶酶切后亚克隆至慢病毒转移质粒,构建携带EGFP及△fgfr1双顺反子自身失活型重组慢病毒表达质粒,通过脂质体转染法与包装质粒及包膜蛋白质粒共转染包装细胞293FT,超速离心浓缩病毒颗粒后转染293FT细胞,用荧光显微镜及流式细胞术(FCM)检测EGFP的表达,免疫印迹法(Western blot)鉴定截短型FGFR1蛋白表达。结果表明,成功克隆小鼠fgfr1基因,构建重组慢病毒转移载体LV-IRES-EGFP-△fgfr1及对照载体LV-IRES-EGFP,三质粒系统共转染293FT细胞后获得病毒滴度达到108 TU/ml。以重组病毒载体转染293FT细胞后第4天在荧光显微镜下观察到较强绿色荧光表达,FCM检测转染效率可达95%,Western blot检测显示,转染后293FT细胞表达截短型FGFR1蛋白。结论:成功构建了自身失活型慢病毒载体LV-IRES-EGFP-△fgfr1,并在真核细胞中获得表达。     

中药对低密度脂蛋白受体基因表达的影响

目的 :探讨中药对低密度脂蛋白受体基因表达的影响。方法 :应用逆转录聚合酶链反应 (RT PCR)技术检测 30例高脂血症患者外周血淋巴细胞低密度脂蛋白受体 (L DL R)信使核糖核酸 (m RNA)水平在用药前后的变化。结果 :中药组 15例患者用药后的 L DL R m RNA水平 (0 .6 2 5 4± 0 .16 6 9)较用药前 (0 .2 46 5±0 .1316 )明显升高 (P<0 .0 1)。结论 :中药复方颗粒剂可增强高脂血症患者外周血淋巴细胞 L DL R基因表达水平 ,在分子水平上 ,为中药降脂作用的机制研究提供科学依据。     

脓毒症大鼠肝组织基因表达的研究

目的筛选脓毒症大鼠肝组织中与正常组织差异表达的基因并进行初步功能分析。方法雄性Wistar大鼠30只，随机分为模型组和空白对照组，每组15只。参照盲肠结扎穿孔术（CLP）制备大鼠脓毒症模型，采用含有4096个大鼠基因cDNA克隆的表达谱基因芯片，检测并分析脓毒症大鼠肝组织在CLP后24h的基因表达变化，并以计算机软件筛选出差异表达的基因。结果CLP后24h共筛选出522条与空白对照组相比出现差异的基因，占基因芯片总点数的12．7％，其中244条基因表达下调，278条基因表达上调。结论脓毒症导致的多器官功能障碍综合征（MODS），涉及到一系列与细胞周期、调控、细胞凋亡、免疫相关基因、各种基本生物化学物质代谢酶类基因和能量代谢相关基因、血液相关基因、癌基因相关基因、生长因子类基因、应激反应类基因、细胞信号转导相关基因、DNA结合转录和转录调节因子相关基因、DNA复制与修复相关基因、蛋白质翻译与修饰、加工、降解相关基因等相关的基因表达异常；采用基因芯片检测技术有利于全面揭示脓毒症中的基因表达模式，快速高效地发现新的研究目标和基因治疗途径。     

人可溶性生长刺激表达基因2蛋白的真核表达、纯化和鉴定

目的构建人可溶性生长刺激表达基因2(sST2)蛋白的重组真核表达载体,获得高纯度的人sST2重组蛋白。方法根据人sST2基因序列设计引物,利用RT-PCR技术获得人sST2基因;构建人sST2-pcDNA3.1-his(-)重组真核表达载体;脂质体法转染COS7细胞,表达人sST2重组蛋白,并用镍柱亲和层析法纯化;用western blot和ELISA法对人sST2重组蛋白进行鉴定。结果PCR扩增产物用琼脂糖凝胶电泳分析,结果显示产物长度与预期一致,约为1000 bp;同源性比对分析结果显示,人sST2基因成功插入PGH-T载体;用Bam HⅠ和Hin dⅢ对重组真核表达载体双酶切后凝胶电泳分析,结果显示产物电泳位置与预期一致;表达产物经SDS-PAGE电泳结果显示在相对分子质量(M r)约为65000处有一明显条带,与预期蛋白质位置一致;western blot鉴定结果显示人sST2重组蛋白有His标签,ELISA鉴定结果显示人sST2重组蛋白有与抗sST2抗体结合的特异性抗原表位。结论通过重组DNA技术成功构建人sST2基因重组真核表达载体,通过蛋白质纯化技术成功获得人sST2重组蛋白。     

The use of molecular imaging of gene expression by radiotracers in gene therapy

Introduction: Progress with gene-based therapies has been hampered by difficulties in monitoring the biodistribution and kinetics of vector-mediated gene expression. Recent developments in non-invasive imaging have allowed researchers and clinicians to assess the location, magnitude and persistence of gene expression in animals and humans. Such advances should eventually lead to improvement in the efficacy and safety of current clinical protocols for future treatments.

Areas covered: The molecular imaging techniques for monitoring gene therapy in the living subject, with a specific highlight on the key reporter gene approaches that have been developed and validated in preclinical models using the latest imaging modalities. The applications of molecular imaging to biotherapy, with a particular emphasis on monitoring of gene and vector biodistribution and on image-guided radiotherapy.

Expert opinion: Among the reporter gene/probe combinations that have been described so far, one stands out, in our view, as the most versatile and easy to implement: the Na/I symporter. This strategy, exploiting more than 50 years of experience in the treatment of differentiated thyroid carcinomas, has been validated in different types of experimental cancers and with different types of oncolytic viruses and is likely to become a key tool in the implementation of human gene therapy.     

SV2A基因真核表达质粒构建及其在HEK293T细胞中的表达

目的构建鼠突触囊泡蛋白2A(SV2A)基因的真核表达质粒,并瞬时转染至人胚肾细胞(HEK293T)中,对其表达进行鉴定。方法以APP/PS1双转基因小鼠海马组织的cDNA为模板,扩增得到长2239 bp的SV2A基因编码序列,将此序列插入到真核表达载体p3×Flag-CMV-10多克隆位点区域中,得到真核表达质粒p3×Flag-CMV-10-SV2A,转化后挑取单克隆菌落经双酶切鉴定后送公司测序,将构建成功的重组质粒转染至HEK293T细胞中,利用蛋白质印迹法(Western blot)检测SV2A基因的表达情况。结果成功构建p3×Flag-CMV-10-SV2A重组质粒,并在转染至HEK293T细胞后,验证了相应蛋白表达。结论利用分子克隆技术成功构建了p3×Flag-CMV-10-SV2A真核表达质粒并在HEK293T细胞中正确表达,为后续实验奠定了基础。     

慢性淋巴细胞白血病bcl-2基因表达与重排的研究

人类恶性肿瘤常伴有非随机性染色体异常,并由于使调控细胞生长的基因表达失控而在肿瘤的发生中发挥十分关键的作用。bcl-2基因由于t(14,18)染色体易位而激活在低恶度的非霍奇金淋巴瘤的发生和演变中的作用已举世公认。类似的重排和非重排引起的bcl-2过度表达也见于慢性淋巴细胞白血病。我们应用免疫组化染色和聚合酶链反应检测了11例慢性淋巴细胞白血病bcl-2基因表达和重排,结果发现所有病例均高度表达Bcl-2蛋白,1例有t(14,18)(q32,q21)染色体易位。结论提示慢性淋巴细胞白血病普遍存在bcl-2基因高表达,bcl-2基因在慢性淋巴细胞白血病的发生和发展中发挥着十分重要的作用。