Generation of eGFP expressing recombinant Zaire ebolavirus for analysis of early pathogenesis events and high-throughput antiviral drug screening

Zaire ebolavirus causes large outbreaks of severe and usually fatal hemorrhagic disease in humans for which there is no effective treatment or cure. To facilitate examination of early critical events in viral pathogenesis and to identify antiviral compounds, a recombinant Zaire ebolavirus was engineered to express a foreign protein, eGFP, to provide a rapid and sensitive means to monitor virus replication in infected cells. This genetically engineered virus represents the first insertion of a foreign gene into ebolavirus. We show that Ebola-eGFP virus (EboZ-eGFP) infects known early targets of human infections and serves as an ideal model to screen antiviral compounds in less time than any previously published assay.     

TAT-乙肝病毒靶向核糖核酸酶融合蛋白原核载体的构建及表达

目的：构建蛋白质转导结构域（protein transduciton domain,PTD)TAT和乙肝病毒靶向核糖核酸酶（targeted ribonuclease,TR）融合蛋白的原核表达载体。并在大肠杆菌中表达。方法：将已构建的乙肝病毒靶向核糖核酸酶基因，乙肝病毒核心蛋白（HBVcore protein,HBVc)基因，人嗜酸性粒细胞来源的神经毒素（human eosinophil derived neurotoxin,hEDN)基因，克隆入含PTDTAT的pTAT原核表达载体，在大肠杆菌BL21（DE3）LysS内，以I：PTG诱导融合蛋白表达。表达产物用SDS-PAGE及Western blot分析鉴定。结果：成功地构建了乙肝病毒靶向核糖核酸酶及其两个对照的融合蛋白原核表达载体，并在IPTG诱导下获得特异性表达。结论：Tat-乙肝病毒靶向核糖核酸酶融合蛋白的构建。为体内应用靶向核酸酶治疗乙型肝炎奠定了基础。     

HBV靶向核糖核酸酶真核表达载体的构建及其在2.2.15细胞内的表达

目的 构建人嗜酸性粒细胞来源的神经毒素（hEDN)与乙肝病毒核心蛋白（HBVc)的融合真核表达载体（该融合蛋白即为构建的靶向核糖核酸酶），抑制乙肝病毒在细胞内的复制。方法 分别从HL－60GGG细胞和2．2．15细胞中提取总RNA，用RT－PCR特异性扩增hEDN及HBVc编码基因，将hEDN和HBVc克隆入真核表达载体pcDNA3.1(-),hEND克隆入原核表达载体pGEX4T-1，并以纯化的原核表达产物免疫Balb/c小鼠，制备特异性抗体。用免疫荧光法检测pcDNA3.1(-)/HBVc-hEDN在转染2．2．15细胞内地表达。结果 成功地构建了hDNA和HBVc的真核融合表达载体。，并在2．2．15细胞中较高效地表达。结论 pcDNA3.1(-)/HBVc-hEDN的构建和在2．2．15细胞内的表达，为探索乙型肝炎的治疗开辟了新思路。     

Noonan综合征患者PTPN11基因突变分析

目的 研究中国人Noonan综合征患者非受体型蛋白酪氨酸磷酸酯酶(protein-tyrosine phosphatase,nonreceptor-type 11,PTPN11)基因的突变.方法 收集遗传咨询门诊3例散发的Noonan综合征患者及其无症状父母,外周血提取基因组DNA,PCR产物直接测序法对患者PTPN11基因的全部15个编码区外显子及其邻接的内含子区域进行测序,检出突变后再对其父母的相应外显子区域进行测序,并通过限制性内切酶检测100名无亲缘关系的正常人相应碱基改变以排除多态性,利用网上ClustalW工具分析突变位点所在氨基酸在多个物种中的保守性.结果 在1例患者的第3外显子区域检出一杂合的c.181G＞A碱基取代,导致第61位的天冬氨酸改变为天冬酰胺(p.D61N),在其无症状父母和100名正常个体中无此突变;该位点在多个物种中高度保守.另外2例患者PTPN11基因的编码区未检到突变.结论 p.D61N突变在文献中已有报道,本例患者为新生突变.本研究进一步肯定了 p.D61N为Noonan综合征的致病突变,基因诊断的结果验证了该患者的临床诊断.另外两例Noonan综合征患者可能由其他基因的突变所致,反映了该病的遗传异质性.     

Population-specific spectrum of the F11 mutations in Koreans: evidence for a founder effect

The aim of this study was to investigate a mutation spectrum of F11 among Korean patients with factor XI (FXI) deficiency and to determine the haplotypes of mutations frequently found in Koreans. Thirteen unrelated patients from non-consanguineous families with FXI deficiency were included in the study. In the mutation analysis, the most frequently found mutations were Q263X (four cases; 31%) and Q226X (three cases; 23%). The frequency of Q263X-bearing haplotype was significantly different between normal and patient groups (p = 0.001), which is consistent with a founder effect of Q263X mutation. Testing for the presence of these two mutations should be the first genetic screening in Korean patients with FXI deficiency.     

Immunoglobulin gene rearrangement in B cell deficient mice generated by targeted deletion of the JH locus

B lymphocyte differentiation is characterized by an orderedseries of Ig gene assembly and expression events. In the majorityof normal B cells, assembly and expression of Ig heavy (H) chaingenes precedes that of light (L) chain genes. To determine therole of the Ig heavy chain protein in B cell development andL chain gene rearrangement, we have generated mice that cannotassemble Ig H chain genes as a result of targeted deletion ofthe J_H gene segments in embryonic stem cells. Mice homozygousfor this deletion are devoid of slg⁺ B cells in the bone marrowand periphery. B cell differentiation in these mice is blockedat the large, CD43⁺ precursor stage. However, these precursorB cells do assemble L chain genes at a low level in the absenceof µ H chain proteins. These data demonstrate that rearrangementand expression of the µ H chain gene is not absolutelyrequired for L chain gene rearrangement in vivo. Expressionof µ chains may facilitate either efficient L chain generearrangement or the survival of cells that have rearrangedlight chain genes by promoting the differentiation of large,CD43⁺ to small, CD43^– pre-B cells.     

抗11β-羟类固醇脱氢酶1的单克隆抗体的制备与鉴定

目的:制备抗人11β-羟类固醇脱氢酶1(homo sapiens hydroxysteroid 11-beta dehydrogenase 1,HSD11B1)的单克隆抗体(mAb)并初步鉴定其特性.方法:将正常成人肝组织匀浆离心并分离线粒体,用线粒体总蛋白免疫BALB/c小鼠,采用杂交瘤技术制备mAb,并通过间接ELISA法、Western blot、免疫组化的方法对mAb进行特性鉴定,通过免疫沉淀、Uni-ZAP XR肝脏cDNA表达文库筛选鉴定抗原.结果:通过间接ELISA筛选获得1株可稳定分泌抗人HSD11B1 mAb的杂交瘤细胞系.其分泌的mAb的Ig亚类(型)为IgG1(κ),Western blot结果显示该mAb可以特异地识别相对分子质量(Mr)为35 000的蛋白;应用mAb CBF245对人肝脏cDNA表达文库(Uni-ZAP XR)进行筛选,阳性噬菌斑测序结果显示5个阳性克隆插入序列均为HSD11B1.结论:mAb BAD062特异地识别抗原HSD11B1,该mAb可用于ELISA检测、Western blot、免疫组化和免疫沉淀实验,为HSD11B1的研究提供了有力的工具.     

Functional characterization and targeted correction of ATM mutations identified in Japanese patients with ataxia-telangiectasia

A recent challenge for investigators studying the progressive neurological disease ataxia-telangiectasia (A-T) is to identify mutations whose effects might be alleviated by mutation-targeted therapies. We studied ATM mutations in eight families of Japanese A-T patients (JPAT) and were able to identify all 16 mutations. The probands were compound heterozygotes in seven families, and one (JPAT2) was homozygous for a frameshift mutation. All mutations--four frameshift, two nonsense, four large genomic deletions, and six affecting splicing--were novel except for c.748C>T found in family JPAT6 and c.2639-384A>G found in family JPAT11/12. Using an established lymphoblastoid cell line (LCL) of patient JPAT11, ATM protein was restored to levels approaching wild type by exposure to an antisense morpholino oligonucleotide designed to correct a pseudoexon splicing mutation. In addition, in an LCL from patient JPAT8/9, a heterozygous carrier of a nonsense mutation, ATM levels could also be partially restored by exposure to readthrough compounds (RTCs): an aminoglycoside, G418, and a novel small molecule identified in our laboratory, RTC13. Taken together, our results suggest that screening and functional characterization of the various sorts of mutations affecting the ATM gene can lead to better identification of A-T patients who are most likely to benefit from rapidly developing mutation-targeted therapeutic technologies.     

Mutations in the human LKB1/STK11 gene

The human LKB gene (official HUGO symbol, STK11) encodes a serine/threonine protein kinase that is defective in patients with Peutz-Jeghers syndrome (PJS). PJS is an autosomal dominantly inherited syndrome characterized by hamartomatous polyposis of the gastrointestinal tract and mucocutaneous pigmentation. To date, 145 different germline LKB1 mutations have been reported. The majority of the mutations lead to a truncated protein product. One mutational hotspot has been observed. A 1-bp deletion and a 1-bp insertion at the mononucleotide repeat (C6 repeat, c.837-c.842) between the codons 279-281 have been found in six and seven unrelated PJS families, respectively. However, these mutations account only for approximately 7% of all mutations identified in the PJS families (13/193). A review of the literature provides a total of 40 different somatic LKB1 mutations in 41 sporadic tumors and seven cancer cell lines. Mutations occur particularly in lung and colorectal cancer. Most of the somatic LKB1 mutations result in truncation of the protein. A mutational hotspot seems to be a C6 repeat accounting for 12.5% of all somatic mutations (6/48). These results are concordant with the germline mutation spectrum. However, the proportion of the missense mutations seems to be higher among the somatic mutations (45%) than among the germline mutations (21%), and only seven of the mutations are exactly the same in both of the mutation types.     

Trypanosoma cruzi carrying a targeted deletion of a Tc52 protein-encoding allele elicits attenuated Chagas' disease in mice

The intracellular protozoan parasite Trypanosoma cruzi is the etiological agent of Chagas' disease. We have previously characterized a T. cruzi virulence factor named Tc52 sharing structural and functional properties with the thioredoxin and glutaredoxin protein family. Single mutant parasite clones (Tc52(+/-)) exhibiting low virulence in vitro and in vivo were obtained by targeted Tc52 gene replacement. In this report, we have extended our study to analyze the immune response and the disease phenotype in Tc52(+/-)-infected BALB/c mice, during the acute and chronic phases of the disease. Significantly lower parasitemia were found in Tc52(+/-)-infected mice, as compared to wild-type parasite (WT)-infected ones. However, the expansion of all classes of lymphocytes and macrophages was similar for both clones. Furthermore, except for IgG2b levels which were higher in the case of WT-infected mice, all classes of Ig presented no significant difference for WT and Tc52(+/-)-infected animals. Interestingly, a lack of suppression of IL-2 production and of T-cell proliferation inhibition was observed in the case of spleen cells from Tc52(+/-)-infected mice. Finally, the pattern of inflammation process was different and characterized as diffused in the case of Tc52(+/-)-infected mice, or presenting numerous foci in the case of WT-infected mice. Localization of the Tc52 protein in tissue sections and infected heart cell primary cultures by immunofluorescence and immunogold labeling, respectively, revealed the presence of Tc52 at the amastigote surface and associated to aggregates within host cell vesicles. Taken together, these results reinforce the notion of Tc52 being a virulence factor playing a role in the phenotype of the immune response associated to the infection and on the course of the disease.     

Receptor expression in orbital inflammatory syndromes and implications for targeted therapy

To investigate the expression of multiple therapeutic targets in tissue specimens from patients with orbital inflammatory syndromes, the clinical records of 16 patients treated for orbital inflammation between January 2003 and November 2005 for whom tissue blocks were available were reviewed retrospectively. Immunohistochemical staining was performed on archived specimens using commercially available monoclonal antibodies against CD3, CD20, CD22, CD23, CD25, and CD52 antigens. The histologic diagnoses were confirmed, and the immunohistochemical staining patterns were agreed upon by both collaborating pathologists (JLJ and PC-B). The study included 13 women and 3 men who ranged in age from 4 to 79 years (mean, 46 years). The histologic diagnoses were as follows: orbital pseudotumor in six patients; sarcoidosis, three; eosinophilic granuloma, one; necrobiotic xanthogranuloma, one; nonspecified granulomatous inflammation, one; Graves' ophthalmopathy, one; Wegener's granulomatosis, one; and reactive lymphoid hyperplasia, two. One orbital lymphoma specimen and one foreign body reaction specimen were used as controls. CD20 was strongly expressed in all specimens except three (Wegener's granulomatosis, eosinophilic granuloma, and nonspecified granulomatous inflammation specimens), and CD25 was strongly expressed in all specimens except the Wegener's granulomatosis specimen, in which this antigen was only moderately expressed. CD20 and CD25 were strongly or moderately expressed in most of the tested specimens of orbital inflammation. If our findings are confirmed in a larger study, rituximab, which targets CD20, and denileukin diftitox (ONTAK), which targets CD25, should be considered for future clinical trials for orbital inflammatory syndromes.     

Co-occurring SHOC2 and PTPN11 mutations in a patient with severe/complex Noonan syndrome-like phenotype

Noonan syndrome (NS) is a heterogeneous disorder caused by activating mutations in the RAS-MAPK signaling pathway. It is associated with variable clinical expression including short stature, congenital heart defect, unusual pectus deformity, and typical facial features and the inheritance is autosomal dominant. Here, we present a clinical and molecular characterization of a patient with Noonan-like syndrome with loose anagen hair phenotype and additional features including mild psychomotor developmental delay, osteoporosis, gingival hyperplasia, spinal neuroblastoma, intrathoracic extramedullary hematopoiesis, and liver hemangioma. Mutation analysis of PTPN11, SOS1, RAF1, KRAS, BRAF, MEK1, MEK2, NRAS, and SHOC2 was conducted, revealing a co-occurrence of two heterozygous previously identified mutations in the index patient. The mutation SHOC2 c.4A > G; p.Ser2Gly represents a de novo mutation, whereas, PTPN11 c.1226G > C; p.Gly409Ala was inherited from the mother and also identified in the brother. The mother and the brother present with some NS manifestations, such as short stature, delayed puberty, keratosis pilaris, café-au-lait spots, refraction error (mother), and undescended testis (brother), but no NS facial features, supporting the notion that the PTPN11 p.Gly409Ala mutation leads to a relatively mild phenotype. We propose that, the atypical phenotype of the young woman with NS reported here is an additive effect, where the PTPN11 mutation acts as a modifier. Interestingly, co-occurrence of RAS-MAPK mutations has been previously identified in a few patients with variable NS or neurofibromatosis-NS phenotypes. Taken together, the results suggest that co-occurrence of mutations or modifying loci in the RAS-MAPK pathway may contribute to the clinical variability observed among NS patients.     

Human granulocyte CD11b expression as a pharmacodynamic biomarker of inflammation

A method has been developed for the direct quantification of the CD11b integrin on granulocytes by flow cytometric analysis of whole blood specimens following either LTB₄ or lipopolysaccharide (LPS) stimulation. This method has utility in evaluating the pharmacodynamic action of either LTB₄ receptor antagonists or immune cell modulators in effecting CD11b integrin expression and granulocyte activation in human subjects administered such drugs. Previous studies using CD11b as a biomarker of granulocyte activation have faltered because of the difficulty in controlling the activation state of the granulocyte following removal of blood from subjects. The present study has made use of a newly validated method using either LTB₄ or LPS to stimulate CD11b expression on granulocytes and has been used, as one measure, in the evaluation of LPS activity when administered to normal human volunteers.     

De novo germline mutation in the serine-threonine kinase STK11/LKB1 gene associated with Peutz-Jeghers syndrome

Peutz-Jeghers syndrome (PJS) is an autosomal dominant disease, characterized phenotypically by mucocutaneous pigmentation and hamartomatous polyposis. Affected patients are at an increased risk of developing gastrointestinal and other malignancies. Mutations in the STK11/LKB1 (LKB1) gene, which encodes for a serine-threonine kinase, have been identified as a genetic cause of PJS. Molecular analysis of the LKB1 gene in a simplex case of PJS revealed a substitution of cytosine (C) for guanine (G) at codon 246 in exon 6, resulting in the Tyr246X mutation. The nucleotide substitution leads to a premature stop codon at the 246 residue, predicting a truncated protein and presumed loss of kinase activity. Analysis of DNA from both parents of the PJS patient did not show this mutation, which is therefore a de novo mutation. We isolated DNA from microdissected gastrointestinal hamartomatous polyps in the PJS patient and investigated the loss of heterozygosity (LOH) at the LKB1 locus by real-time fluorescence polymerase chain reaction genotyping using a fluorescent resonance energy transfer technique. The results suggest a different mechanism from LOH in the formation of hamartomatous polyps.     

实时定量PCR检测白血病中BCL11B基因的表达水平

目的建立BCL11B基因的定量检测方法,并分析其在白血病中的表达水平。方法利用实时定量RTPCR分析TALL(12例)、BALL(8例)、BCLL(6例)、AML(7例)和正常对照(10例)外周血单个核细胞(PBMC)中BCL11B基因的表达水平,以β2微球蛋白(β2M)基因表达水平作为内对照。结果TALL患者PBMC中BCL11B表达水平(553.84±564.01拷贝105β2M拷贝)明显高于正常对照和其他白血病患者(P=0.006,P=0.013,P=0.031,P=0.020);而AML组BCL11B表达水平(0.02±0.04拷贝105β2M拷贝)则明显低于正常对照组(P=0.000)、BALL组(P=0.006)和TALL组(P=0.020);BALL(1.99±1.59拷贝105β2M拷贝)和BCLL(2.26±3.57拷贝105β2M拷贝)中BCL11B表达水平与正常对照(2.20±1.01拷贝105β2M拷贝)无显著差别。结论建立了实时定量RTPCR检测BCL11B方法,TALL中BCL11B高表达可能与其发病有一定关系。     

Progressive loss of synaptic integrity in human apolipoprotein E4 targeted replacement mice and attenuation by apolipoprotein E2

Inheritance of the APOE4 allele is a well established genetic risk factor linked to the development of late onset Alzheimer's disease. As the major lipid transport protein in the central nervous system, apolipoprotein (apo) E plays an important role in the assembly and maintenance of synaptic connections. Our previous work showed that 7 month old human apoE4 targeted replacement (TR) mice displayed significant synaptic deficits in the principal neurons of the lateral amygdala, a region that is critical for memory formation and also one of the primary regions affected in Alzheimer's disease, compared to apoE3 TR mice. In the current study, we determined how age and varying APOE genotype affect synaptic integrity of amygdala neurons by comparing electrophysiological and morphometric properties in C57BL6, apoE knockout, and human apoE3, E4 and E2/4 TR mice at 1 month and 7 months. The apoE4 TR mice exhibited the lowest level of excitatory synaptic activity and dendritic arbor compared to other cohorts at both ages, and became progressively worse by 7 months. In contrast, the apoE3 TR mice exhibited the highest synaptic activity and dendritic arbor of all cohorts at both ages. C57BL6 mice displayed virtually identical synaptic activity to apoE3 TR mice at 1 month; however this activity decreased by 7 months. ApoE knockout mice exhibited a similar synaptic activity profile with apoE4 TR mice at 7 months. Consistent with previous reports that APOE2 confers protection, the apoE4-dependent deficits in excitatory activity were significantly attenuated in apoE2/4 TR mice at both ages. These findings demonstrate that expression of human apoE4 contributes to functional deficits in the amygdala very early in development and may be responsible for altering neuronal circuitry that eventually leads to cognitive and affective disorders later in life.