Visualizing adenosine-to-inosine RNA editing in the Drosophila nervous system

Informational recoding by adenosine-to-inosine RNA editing diversifies neuronal proteomes by chemically modifying structured mRNAs. However, techniques for analyzing editing activity on substrates in defined neurons in vivo are lacking. Guided by comparative genomics, here we reverse-engineered a fluorescent reporter sensitive to Drosophila melanogaster adenosine deaminase that acts on RNA (dADAR) activity and alterations in dADAR autoregulation. Using this artificial dADAR substrate, we visualized variable patterns of RNA-editing activity in the Drosophila nervous system between individuals. Our results demonstrate the feasibility of structurally mimicking ADAR substrates as a method to regulate protein expression and, potentially, therapeutically repair mutant mRNAs. Our data suggest variable RNA editing as a credible molecular mechanism for mediating individual-to-individual variation in neuronal physiology and behavior.     

Novel N,N '-diacyl-1,3-diaminopropyl-2-carbamoyl bivalent cationic lipids for gene delivery--synthesis, in vitro transfection activity, and physicochemical characterization

Novel N,N'-diacyl-1,3-diaminopropyl-2-carbamoyl bivalent cationic lipids were synthesized and their physicochemical properties in lamellar assemblies with and without plasmid DNA were evaluated to elucidate the structural requirements of these double-chained pH-sensitive surfactants for potent non-viral gene delivery and expression. The highest in vitro transfection efficacies were induced at +/-4:1 by the dimyristoyl, dipalmitoyl and dioleoyl derivatives 1,3lb2, 1,3lb3 and 1,3lb5, respectively, without inclusion of helper lipids. Transfection activities were reduced in the presence of either 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine alone or in combination with cholesterol for all derivatives except 1,3lb5, which maintained reporter gene expression levels at +/-4:1 and yielded increased lipofection activity at a lower charge ratio of +/-2:1. Ethidium bromide displacement indicated efficient plasmid DNA binding and compaction by the transfection-competent analogs. Dynamic light-scattering and electrophoretic mobility studies revealed lipoplexes of the active lipids with large particle sizes (mean diameter>or=500 nm) and zeta potentials with positive values (low ionic strength) or below neutrality (high ionic strength). Langmuir film balance studies showed high in-plane elasticity of these derivatives in isolation. In agreement with the monolayer experiments, fluorescence polarization studies verified the fluid nature of the highly transfection-efficient amphiphiles, with gel-to-liquid crystalline phase transitions below physiological temperature. The active compounds also interacted with endosome-mimicking vesicles to a greater extent than the poorly active derivative 1,3lb4, as revealed by fluorescence resonance energy transfer experiments. Taken together, the results suggest that well-hydrated and highly elastic cationic lipids with increased acyl chain fluidity and minimal cytotoxicity elicit high transfection activity.     

The holin of bacteriophage lambda forms rings with large diameter

Holins control the length of the infection cycle of tailed phages (the Caudovirales) by oligomerizing to form lethal holes in the cytoplasmic membrane at a time dictated by their primary structure. Nothing is currently known about the physical basis of their oligomerization or the structure of the oligomers formed by any known holin. Here we use electron microscopy and single-particle analysis to characterize structures formed by the bacteriophage λ holin (S105) in vitro . In non-ionic or mild zwitterionic detergents, purified S105, but not the lysis-defective variant S105_A52V, forms rings of at least two size classes, the most common having inner and outer diameters of 8.5 and 23 nm respectively, and containing approximately 72 S105 monomers. The height of these rings, 4 nm, closely matches the thickness of the lipid bilayer. The central channel is of unprecedented size for channels formed by integral membrane proteins, consistent with the non-specific nature of holin-mediated membrane permeabilization. S105 present in detergent-solubilized rings and in inverted membrane vesicles showed similar sensitivities to proteolysis and cysteine-specific modification, suggesting that the rings are representative of the lethal holes formed by S105 to terminate the infection cycle and initiate lysis.     

High IFN－α expression is associated with the induction of experimental autoimmune uveitis （EAU） in Fischer 344 rat

INTRODUCTIONThe CD4 T cells can be subdivided intoTh1 and Th2 subsets based on their secreted cy-tokine profile. Th1 cells characteristical1y secreteInterferonry (IFN--ry), whereas Th2 cells maiuly pro--duce IL--4[1]. IL-12 po1arizes the differentiation ofnaitre, CD4 T cells towards Th1 pathWay, in con-trast IL--4 directs T cell differentiation towards Th2pathWay The broken balance between Th1 and Th2immune responses and predominant Th1 responseare crucial factors in initiation…     

Identification and expression of epidermal growth factor gene in mouse testis

INTRODUCTIONEpidermalgrowthfactor(EGF)wasinitiallyisolatedandpurifiedfromthesubmaxillarygland(SMG)ofmalemouse[1].Itisapolypeptidecomposedof53aminoacidresidues[2].Itinfluencescellproliferationanddifferentiationandmodulatesthegrowthanddevelopmentofmammalianorgans[3--7].AnoteworthyfindingisthatextirpationofmouseSMGresultsinamarkedreductionofserumEGFconcentrationassociatedwithanimpairedspermatogenesis[3].ThisfindingsuggeststhatEGFmayregulatespermproductionanddifferentiation.Inhumantest…     

基于戴云山固定样地黄山松群落物种组成与结构研究

黄山松是亚热带中部山区主要建群种,研究其物种组成及群落结构对探讨中亚热带植被演替规律具有重要意义。戴云山自然保护区分布有大面积黄山松群落,该研究采用网格布点法,建立86块(25.82 m×25.82 m)共5.7 hm~2固定样地,对样地内黄山松群落的物种组成特征、分布区类型、胸径和树高结构、空间分布格局4个方面特征进行了探讨。结果表明:(1)样地内共出现木本植物32 603株219种,隶属于59科108属。乔灌木优势种有黄山松、马尾松、木荷、肿节少穗竹、岩柃、窄基红褐柃等,其中稀有种和偶见种分别占总物种数的33.79%、25.75%和45.21%、24.66%。(2)在区系分布类型上,热带分布类型的科属多于温带分布类型的科属,热带分布类型中又以泛热带分布类型,温带分布类型以北温带占据最大比例。(3)样地内优势种的胸径分布呈倒"J"型,表明更新状态良好。垂直结构上,各优势种树高为倒"J"型或近似倒"J"型。黄山松和其他优势乔木大部分树高为4~10 m,灌木除短尾越桔0~1 m个体数最多外,其他优势灌木1~2 m个体数最多。(4)经计算,样地内乔灌木各优势种均呈聚集分布,聚集程度有所差异,乔木层黄山松最低,灌木层短尾越桔最低。该研究结果表明戴云山保护区黄山松群落物种组成丰富、更新良好,反映了亚热带高山针叶林的典型特征,其空间分布格局可能与取样方式等因素有关。     

Prd29A及DREB1A的克隆和干旱诱导型植物表达载体的构建与鉴定

从拟南芥中克隆了RD29A基因的启动子(Prd29A)及DREB1M基因的DNA片段,构建Prd29A:DREB1A融合基因,采用合成的接头将该融合基因插入到植物表达载体pBI121中,经鉴定,确认正确.