真核表达载体pIRES2-EGFP-Nurr1的构建及鉴定

目的:构建带有增强型绿色荧光蛋白报告基因EGFP及目的基因Nurr1的真核表达载体pIRES2-EGFP-Nurr1,并检测其在293T细胞中的表达。方法:采用反转录-聚合酶链式反应(RT-PCR)方法从大鼠黑质中获取Nurrl基因,连接T载体测序正确后与真核空载体pIRES2-EGFP一起,经Nhe1和Xho1双酶切,T4 DNA连接酶连接,构建pIRES2-EGFP-Nurr1;真核表达载体pIRES2-EGFP-Nurr1测序正确后采用脂质体法将其转染293T细胞,倒置荧光显微镜下观察转染效率,PCR检测Nurr1基因mRNA水平的表达情况,免疫印迹试验(Western Blot)检测Nurr1蛋白的表达水平。结果:酶切及测序鉴定证实成功构建了重组真核表达载体pIRES2-EGFP-Nurr1;293T细胞转染pIRES2-EGFP-Nurr1后可以高度表达绿色荧光,有效转录Nurr1基因并正确的高表达Nurr1蛋白。结论:成功构建Nurr1真核表达载体且在293T细胞中高水平表达,为进一步转染大鼠骨髓间充质干细胞(BMSCs),基因治疗帕金森病奠定基础。     

2A肽介导猪PID1与CuZnSOD双基因真核共表达载体的构建与细胞表达

构建PID1基因与CuZnSOD基因的真核共表达载体,在PK15细胞中鉴定基因的表达。PCR扩增的PID1与CuZnSOD两基因分别经双酶切后定向插入pIRES2-AcGFP1空载体,构建pIRES2-CuZnSOD-PID1真核双表达载体并进行测序与酶切鉴定。采用脂质体转染法将重组质粒转染至PK15细胞,细胞内荧光显微镜下观察其荧光的表达,RT-PCR、Westernblot技术分别检测PID1基因与CuZnSOD基因mRNA和蛋白表达情况。重组克隆载体插入目的片段序列与PID1基因与CuZnSOD基因序列完全一致。PIRES2-CuZnSOD-PID1真核双表达载体测序、酶切鉴定结果与预期结果一致。荧光显微镜下观察转染后的PK15细胞出现绿色荧光。RT-PCR检测结果显示,转染细胞中PID1基因与CuZnSOD基因表达量明显高于对照组（P〈0.05）。Westernblot检测结果表明pIRES2-CuZnSODPID1真核双表达载体稳定有效表达。成功构建pIRES2-CuZnSOD-PID1真核共表达载体,且双基因在真核细胞独立稳定表达,为转基因猪等育种新材料的制备奠定基础。     

小鼠DLL1真核表达载体的构建及其在肿瘤细胞中的表达

目的：构建带绿色荧光蛋白的小鼠DLL1全长基因真核表达载体,并在肿瘤细胞中表达。方法：利用PCR特异性引物扩增出DLL1基因全长,将克隆的基因片段插入带绿色荧光蛋白的真核表达载体pIRES2-EGFP质粒中。然后利用脂质体将重组质粒pIRES2-EGFP-DLL1转染进小鼠B16黑色素瘤细胞中,并通过G418筛选后选取生长良好、荧光强度高的三株单克隆进行mRNA水平DLL1表达的鉴定。结果：成功扩增小鼠DLL1的全长基因。克隆入质粒载体后,通过DNA序列测定证实其序列正确。将构建的pIRES2-EGFP-DLL1质粒转染小鼠B16黑色素瘤细胞,经过G418筛选和荧光显微镜观察后,挑选得到GFP阳性率90%以上的稳定转染细胞株。RT-PCR检测稳定转染细胞的mDLL1的表达显著增加,进一步证实了pIRES2-EGFP-DLL1的表达效能。结论：成功构建了小鼠DLL1基因的真核表达质粒,证实其在真核细胞B16中可以表达。     

小鼠DLL1真核表达载体的构建及其在肿瘤细胞中的表达

目的:构建带绿色荧光蛋白的小鼠DLL1全长基因真核表达载体,并在肿瘤细胞中表达。方法:利用PCR特异性引物扩增出DLL1基因全长,将克隆的基因片段插入带绿色荧光蛋白的真核表达载体pIRES2-EGFP质粒中。然后利用脂质体将重组质粒pIRES2-EGFP-DLL1转染进小鼠B16黑色素瘤细胞中,并通过G418筛选后选取生长良好、荧光强度高的三株单克隆进行mRNA水平DLL1表达的鉴定。结果:成功扩增小鼠DLL1的全长基因。克隆入质粒载体后,通过DNA序列测定证实其序列正确。将构建的pIRES2-EGFP-DLL1质粒转染小鼠B16黑色素瘤细胞,经过G418筛选和荧光显微镜观察后,挑选得到GFP阳性率90%以上的稳定转染细胞株。RT-PCR检测稳定转染细胞的mDLL1的表达显著增加,进一步证实了pIRES2-EGFP-DLL1的表达效能。结论:成功构建了小鼠DLL1基因的真核表达质粒,证实其在真核细胞B16中可以表达。     

人HCN2真核表达载体的构建及在HEK293细胞中的表达

目的：构建含有人HCN2基因的真核表达载体,并观察在人胚胎肾细胞（HEK293）中的表达情况。方法：对人HCN2基因全序列进行分析,进行oligo设计,通过PCR,扩增HCN2全长cDNA,通过双酶切（XhoI和BamHI）装入真核表达载体pIRES2-EGFP中,脂质体法转染入HEK293细胞中,利用真核表达载体中带有绿色荧光蛋白GFP报告基因,对转染效率进行监测,采用反转录-聚合酶链反应检测HCN2 mRNA表达,全细胞膜片钳技术检测HCN2通道电流。结果：测序及酶切结果表明HCN2基因正确,荧光显微镜下,转染细胞观察到绿色荧光,反转录-聚合酶链反应检测到HCN2 mRNA表达,膜片钳检测到hHCN2基因编码的通道电流。结论：成功地构建了HCN2真核表达载体并进行了起搏通道HCN2基因的异源性表达。     

人HCN2 真核表达载体的构建及在HEK293 细胞中的表达

目的:构建含有人HCN2基因的真核表达载体,并观察在人胚胎肾细胞(HEK293)中的表达情况。方法:对人HCN2基因全序列进行分析,进行oligo设计,通过PCR,扩增HCN2全长cDNA,通过双酶切(XhoI和BamHI)装入真核表达载体pIRES2-EGFP中,脂质体法转染入HEK293细胞中,利用真核表达载体中带有绿色荧光蛋白GFP报告基因,对转染效率进行监测,采用反转录-聚合酶链反应检测HCN2 mRNA表达,全细胞膜片钳技术检测HCN2通道电流。结果:测序及酶切结果表明HCN2基因正确,荧光显微镜下,转染细胞观察到绿色荧光,反转录-聚合酶链反应检测到HCN2 mRNA表达,膜片钳检测到hHCN2基因编码的通道电流。结论:成功地构建了HCN2真核表达载体并进行了起搏通道HCN2基因的异源性表达。     

SCG10基因重组质粒的构建及蛋白表达和定位

目的构建SCG10真核表达载体并证实融合蛋白在细胞内表达及定位。方法以人胎脑cDNA文库为模板,PCR扩增SCG10全长编码基因,亚克隆至pEGFP-C1表达载体中。将构建的重组质粒测序并转染到人胚肾HEK293中,提取细胞蛋白进行Western blot检测。利用共聚焦激光扫描显微镜观察pEGFP-SCG10在HEK293细胞内定位。结果 SCG10全长基因序列克隆到了真核表达载体pEGFP-C1中,酶切鉴定片段大小540bp。Western blot检测到了融合蛋白表达,分子量约为48kD。pEGFP-SCG10在细胞内定位以细胞浆为主,在细胞核少量表达。结论成功构建了SCG10全长基因真核表达载体,pEGFP-SCG10蛋白主要定位于HEK293细胞浆内。     

人MACC1-SH3基因片段的克隆、表达载体的构建与转染

目的:本研究构建MACC1-SH3基因的真核表达栽体,为进一步研究MACC1-SH3在结肠癌细胞转移中的作用机理奠定基础.方法:本研究通过RT-PCR方法从人转移性结肠癌细胞SNU-C1中获得MACC1-SH3基因片段,并插入pRc/CMV真核表达栽体.将该质粒转染SW480结肠癌细胞株.结果:将工程菌扩增后的质粒经双酶切鉴定和基因测序证实插入片段为MACC1-SH3基因,并得到含有pRc/CMV-MACC1-SH3质粒的结肠癌细胞株.结论:通过基因工程技术构建pRc/CMV-MACC1-SH3质粒载体,并成功转染结肠癌细胞株.     

FLT-1启动子在血管内皮细胞中特异生物活性的检测及其意义

目的:构建带有组织特异性 FLT-1 启动子的真核表达栽体,检测其在转染的人脐静脉内皮细胞(HUVEC)中对荧光素酶报告基因表达的驱动能力.方法:采用PCR扩增FLT-1启动子,插入到pGL3-Basic-luc载体中,构建携带FLT-1启动子的真核表达载体pGL3-FLT-Basic-luc,经脂质体法转染HUVEC、HepG2、NIH3T3和HEK293 细胞,于转染48h后采用双荧光报告系统检测荧光素酶表达活性.结果:酶切及测序证实构建的pGL3-FLT-Basic-luc栽体中含有序列正确的FLT-1基因启动子,双荧光报告系统检测显示,转染的HUVEC细胞其荧光素酶活性明显高于HEK293细胞(P<0.01),而转染的HepG2和NIH3T3细胞中未检测出荧光素酶表达.结论:克隆的FLT-1启动子具有较高的血管内皮特异性转录活性,可作为血管疾病靶向基因治疗的启动子来源.     

人M2型丙酮酸激酶促进肾癌细胞生长

目的:构建带myc标签的人M2型丙酮酸激酶(PKM2)的真核表达载体,并瞬时转染肿瘤细胞,初步探讨PKM2的生物学功能。方法:以人乳腺文库为模板,采用PCR技术扩增PKM2基因,将其插入p XJ-40-myc载体,双酶切和基因测序验证后转染人胚肾293T细胞,Western印迹验证表达;将重组基因和空载体分别转染人肾透明细胞癌Caki-1细胞,CCK8法测定并绘制细胞生长曲线。结果:从人乳腺文库中获得长约1500 bp的DNA片段,连接到p XJ-40-myc载体上,测序结果与目的序列完全一致;转染人胚肾293T细胞后获得表达;细胞生长曲线结果显示,转染myc-PKM2的Caki-1细胞生长较空载体细胞快。结论:构建了myc-PKM2真核表达载体,为进一步研究PKM2在肿瘤发生发展中的作用奠定了基础。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.