Distinctive population of Gfap‐expressing neural progenitors arising around the dentate notch migrate and form the granule cell layer in the developing hippocampus

In the adult hippocampus, granule cells continue to be generated from astrocyte‐like progenitors expressing glial fibrillary acidic protein (GFAP) that differ from embryonic neocortical progenitors. However, during the embryonic period, dentate granule neurons and neocortical pyramidal neurons are derived from the ventricular zone (VZ) of the pallium. Our question is when do GFAP+ progenitors of granule neurons appear in the developing hippocampus during the embryonic period, and how do they form the granule cell layer. The present analysis using Gfap‐GFP transgenic mice shows that the GFP+ distinct cell population first appears in the VZ of the medial pallium at the dorsal edge of the fimbria on embryonic day 13.5. During the perinatal period, they form a migratory stream from the VZ to the developing dentate gyrus, and establish the germinal zones in the migratory stream, and the marginal and hilar regions in the developing dentate gyrus. GFP+ cells in these regions were positive for Sox2 and Ki67, but negative for BLBP. GFP+ cells with Neurogenin2 expression were largely distributed in the VZ, whereas GFP+ cells with Tbr2 and NeuroD expressions were seen in the migratory stream and developing dentate gyrus. Prox1‐expressing GFP+ cells were restricted to the developing dentate gyrus. These results suggest that distinctive Gfap‐expressing progenitors arising around the dentate notch form germinal regions in the migratory stream and the developing dentate gyrus where they differentiate into granule neurons, indicating that distinct astrocyte‐like neural progenitors continue to generate granule neurons, from the beginning of dentate development and throughout life. J. Comp. Neurol. 522:261–283, 2014. © 2013 Wiley Periodicals, Inc.     

蚊期和红内期持续表达绿色荧光蛋白的重组约氏疟原虫

目的 构建蚊期、红内期持续表达绿色荧光蛋白（GFP）的约氏疟原虫BY265株。 方法 用SacⅡ酶酶切含有伯氏疟原虫ssu-rrna基因和GFP基因的重组质粒pl0017使之线性化,用电转化的方法将该重组质粒转化入红内期约氏疟原虫BY265株,获BY265-EGFP重组疟原虫,尾静脉注射感染昆明小鼠,24～30 h后用乙胺嘧啶饲喂小鼠5～6 d,鼠尾静脉采血涂片观察原虫感染率。以疟原虫基因组DNA为模板,PCR鉴定转染重组质粒pl0017的约氏疟原虫。斯氏按蚊叮咬感染BY265-EGFP重组疟原虫的小鼠,按蚊血餐后第7天和第16天解剖蚊胃和唾液腺,观察疟原虫能否在蚊体内正常发育。 结果 荧光显微镜观察到呈绿色荧光的红内期各期形态正常的约氏疟原虫。PCR检测结果表明,GFP和ssu-rrna基因已成功整合到约氏疟原虫基因组中。按蚊感染实验证实重组BY265株能在蚊体内正常发育。 结论 构建了蚊期、红内期持续表达绿色荧光蛋白的约氏疟原虫。     

CD2AP真核表达载体的构建及在COS-7细胞中的表达定位

目的:构建pEGFP-CD2AP真核表达载体,检测其在COS-7细胞中的表达.方法:PCR扩增CD2相关蛋白(CD2-associated protein,CD2AP)全长编码序列,PCR产物连接入pGEM T-Easy载体,经测序确认无误后,亚克隆入pEGFP-C2构建pEGFP-CD2AP真核表达载体,采用Lipofectamine 2000转染COS-7细胞,荧光显微镜检测报告基因表达产物EGFP.结果:pEGFP-CD2AP表达载体转染COS-7细胞后,可在细胞内观察到报告基因和目的基因的表达产物.结论:pEGFP-CD2AP真核表达载体构建成功,并可在细胞内表达,这将为今后的CD2AP功能研究奠定基础.     

高危型HPV-16E6在小鼠骨髓源性树突细胞的表达

目的探讨高危型HPV-16E6在树突细胞中的定位。方法构建真核表达载体pGFP-16E6,转染小鼠骨髓源性的树突细胞,在荧光显微镜下动态观察高危型HPV-16E6蛋白在树突细胞内的定位和表达水平。结果树突细胞在分别转染pGFP-16E6和pEGFP-C1质粒后,GFP-16E6主要定位于细胞核内,而对照组的只表达GFP的蛋白则均匀分布于树突细胞。蛋白表达水平的检测表明,在转染树突细胞后的12h,GFP-16E6和GFP蛋白开始表达（荧光强度分别为31.29,39.52）,转染后至24h,蛋白表达均到达高峰（荧光强度分别为119.37,134.23）,24h后,蛋白表达逐渐降低。结论 HPV-16E6主要定位于树突细胞核内,随时间其蛋白表达水平不同,这为HPV E6的树突细胞疫苗发挥有效的抗癌作用提供理论依据。     

FM1-43造影观察PC12神经元与原代皮层神经元间的突触形成

目的 观察种植到原代皮层神经元中的PCI2细胞，在神经生长因子(nerve growth factor NGF)作用下分化成的神经元样细胞与原代皮层神经元之间功能性突触的形成，研究细胞移植环境中宿主细胞和移植细胞形成神经连接的可能及过程。方法 将绿色荧光蛋白(enhenced green flourescent protein EGFP)标记的PC12细胞种植到原代神经元中，建立共培养系统。NGF诱导其中的PC12细胞分化为神经元样细胞，可能与共培养的原代神经元形成突触连接。高钾离子的去极化刺激使突触末端囊泡被FM143染色，激光共聚焦扫描显微镜下观察，电子图像显示出活性的突触末端。结果 和对照组相比共培养系统中PC12神经元更成熟，FM1—43造影显示这些新的神经元与原代神经元之间产生了功能性突触囊泡活动。结论 与原代的神经细胞共培养有利于PCI2细胞在NGF作用下分化为神经元样细胞及形成神经突起，新形成的神经元可以和宿主神经元形成突触连接。     

巨型辐花海葵荧光蛋白类似物基因的原核表达比较

目的：探讨巨型辐花海葵荧光蛋白类似物基因hmGFP的生物学特性及应用的可能性。方法：构建了hmGFP的两个原核表达载体并进行诱导表达。结果：低温下hmGFP获得了功能性表达而发光。深入比较了重组巨型辐花海葵荧光蛋白类似物基因hmGFP在两个表达体系中的表达差异，其中pETTFRX-hmGFP的重组蛋白表达水平和可溶性均比pET21b—hmGFP高。结论：对pETTFRX—hmGFP的表达条件进行了优化，为下一步hmGFP成熟重组蛋白的纯化及其荧光波谱分析奠定了良好基础。     

Pyridine N-oxide derivatives inhibit viral transactivation by interfering with NF-kappaB binding

Pyridine N-oxide derivatives represent a new class of anti-HIV compounds for which some members exclusively inhibit HIV-1 RT, whereas other members act, additionally or alternatively, at a post-integrational event in the replicative cycle of HIV. A prototype pyridine N-oxide derivative, JPL-32, inhibited tumor necrosis factor alpha (TNF-alpha)-induced HIV-1 expression in latently HIV-1-infected OM-10.1 and U1 cells, which could be reversed by the addition of N-acetyl-L-cysteine (NAC). The reversal of the antiviral activity of JPL-32 by NAC suggested the possible role of a redox-sensitive factor as target of inhibition. Indeed, when nuclear extracts of TNF-alpha-stimulated OM-10.1 and U1 cells cultured in the presence of JPL-32 were analyzed by an electrophoretic mobility shift assay (EMSA), a dose-dependent inhibition of DNA binding of nuclear NF-kappaB was observed, which could be reversed by the addition of NAC. JPL-32 did not inhibit the release and subsequent degradation of IkappaBalpha, nor did JPL-32 affect the nuclear translocation of NF-kappaB. EMSA revealed that the inhibition of the NF-kappaB DNA binding activity by JPL-32 could be reversed by the addition of reducing agents such as dithiothreitol or beta-mercaptoethanol. Moreover, JPL-32 was able to directly oxidize the thiol groups on the purified p50 subunit of recombinant NF-kappaB. The oxidative modification of the thiol groups on NF-kappaB by JPL-32 could be ascribed to the intracellular pro-oxidant effect of JPL-32. Consequently, JPL-32 was able to increase the intracellular glutathione (GSH) levels and to induce apoptosis in a dose-dependent way.     

Identification of the heparin binding site on adeno-associated virus serotype 3B (AAV-3B)

Adeno-associated virus is a promising vector for gene therapy. In the current study, the binding site on AAV serotype 3B for the heparan sulfate proteoglycan (HSPG) receptor has been characterized. X-ray diffraction identified a disaccharide binding site at the most positively charged region on the virus surface. The contributions of basic amino acids at this and other sites were characterized using site-directed mutagenesis. Both heparin and cell binding are correlated to positive charge at the disaccharide binding site, and transduction is significantly decreased in AAV-3B vectors mutated at this site to reduce heparin binding. While the receptor attachment sites of AAV-3B and AAV-2 are both in the general vicinity of the viral spikes, the exact amino acids that participate in electrostatic interactions are distinct. Diversity in the mechanisms of cell attachment by AAV serotypes will be an important consideration for the rational design of improved gene therapy vectors.     

Molecular cloning, characterization and expression analysis of the tumor necrosis factor (TNF) superfamily gene, TNF receptor superfamily gene and lipopolysaccharide-induced TNF-α factor (LITAF) gene from Litopenaeus vannamei

In vertebrates, the tumor necrosis factor (TNF)-receptor (TNFR) system participates in diverse physiological and pathological events, such as inflammation and protective immune responses to microbial infections. There are few reports about the role of the invertebrate TNF-TNFR system in immune responses. Here, we isolated and characterized the TNF superfamily (LvTNFSF) gene, TNFR superfamily (LvTNFRSF) gene and lipopolysaccharide-induced TNF-α factor (LvLITAF) gene from Litopenaeus vannamei. LvTNFSF consists of 472 amino acids with a conserved C-terminal TNF domain and has 89.8% identity with the Marsupenaeus japonicus TNF superfamily gene. LvTNFRSF consists of 296 amino acids with a conserved TNFR domain and has 18.0% identity with Chlamys farreri TNFR, 14.6% identity with Drosophila melanogaster Wengen and 14.6% identity with Homo sapiens TNFR1. LvLITAF consists of 124 amino acids with the LITAF domain and shows 62.6% identity with D. melanogaster LITAF and 32.3% identity with H. sapiens LITAF. The promoter region of LvTNFSF was cloned and used to construct a luciferase reporter. In Drosophila S2 cells, the promoter of LvTNFSF can be activated by LvLITAF, L. vannamei NF-κB family proteins (LvRelish and LvDorsal) and LvSTAT. Unlike its mammalian counterparts, LvTNFRSF could not activate the NF-κB pathway in Drosophila S2 cells. Using real-time quantitative PCR, we obtained expression profiles of LvTNFSF, LvTNFRSF and LvLITAF in the gill, intestine and hepatopancreas of L. vannamei after challenge with Gram-negative Vibrio alginolyticus, Gram-positive Staphylococcus aureus, the fungus Candida albicans and white spot syndrome virus (WSSV). Taken together, our results reveal that LvTNFSF, LvTNFRSF and LvLITAF may be involved in shrimp immune responses to pathogenic infections.     

Molecular cloning, characterization and expression analysis of two novel Tolls (LvToll2 and LvToll3) and three putative Spätzle-like Toll ligands (LvSpz1-3) from Litopenaeus vannamei

Toll-like receptor-mediated NF-κB pathways are essential for inducing immune related-gene expression in the defense against bacterial, fungal and viral infections in insects and mammals. Although a Toll receptor (LvToll1) was cloned in Litopenaeus vannamei, relatively little is known about other types of Toll-like receptors and their endogenous cytokine-like ligand, Spätzle. Here, we report two novel Toll-like receptors (LvToll2 and LvToll3) and three Spätzle-like proteins (LvSpz1-3) from L. vannamei. LvToll2 has 1009 residues with an extracellular domain containing 18 leucine-rich repeats (LRRs) and a cytoplasmic Toll/interleukin-1 receptor (TIR) domain of 139 residues. LvToll3 is 1244 residues long with an extracellular domain containing 23 LRRs and a cytoplasmic TIR domain of 138 residues. The Spätzle-like proteins LvSpz1, LvSpz2 and LvSpz3 are 237, 245 and 275 residues in length, respectively, and all of them have a putative C-terminal cystine-knot domain. In Drosophila Schneider 2 (S2) cells, LvToll1 and LvToll3 were localized to the membrane and cytoplasm, and LvToll2 was confined to the cytoplasm. In Drosophila S2 cells, LvToll2 could significantly activate the promoters of NF-κB-pathway-controlled antimicrobial peptide genes, whereas LvToll1 and LvToll3 had no effect on them. LvSpz1 exerted some degree of inhibition on the promoter activities of Drosophila Attacin A and L. vannamei Penaeidin4. LvSpz3 also inhibited the Drosophila Attacin A promoter, but LvSpz2 could only slightly activate it. LvToll1, LvToll2 and LvToll3 were constitutive expressed in various tissues, while LvSpz1, LvSpz2 and LvSpz3 exhibited tissue-specific expression in the epithelium, eyestalk, intestine, gill and muscle. In the gill, after Vibrio alginolyticus challenge, LvToll1 was upregulated, but LvToll2 and LvToll3 showed no obvious changes. LvSpz1 and LvSpz3 were also strongly induced by V. alginolyticus challenge, but LvSpz2 only showed a slight downregulation. In the gill, after white spot syndrome virus (WSSV) challenge, LvToll1, LvToll2, LvToll3, LvSpz1 and LvSpz3 were upregulated, but LvSpz2 showed no obvious change, except for a slight downregulation at 12 h post-injection of WSSV. These findings might be valuable in understanding the innate immune signal pathways of shrimp and enabling future studies on the host-pathogen interactions in V. alginolyticus and WSSV infections.