肌动蛋白和Tau蛋白荧光蛋白融合载体的构建、表达及其细胞内定位

背景:肌动蛋白和Tau蛋白分别是微丝和微管的重要组成成分,肌动蛋白和Tau蛋白的分布能否作为微丝和微管的观察指标.目的:构建肌动蛋白和Tau蛋白的红色和绿色荧光蛋白融合表达载体并转染真核细胞,观察其在细胞内的表达和定位情况.设计、时间及地点:单一样本观察实验,于2008-03/08在南方医科大学病理生理学教研室和广东省蛋白质组学重点实验室共同完成.材料:克隆在pcDNA3载体上的肌动蛋白和Tau蛋白真核表达载体pcDNA3-actin和pcDNA3-Tau,以及红色荧光蛋白表达载体pmCherry-C2和绿色荧光蛋白表达载体pEGFP-C2、大肠杆菌株DH5α和小鼠NIH3T3细胞系由南方医科大学病理生理学教研室保存.方法:将克隆在pcDNA3上的肌动蛋白和Tau蛋白亚克隆到红色荧光蛋白载体pmCherry-C2和绿色荧光蛋白载体pEGFP-C2上,然后转染NIH3T3细胞,利用荧光显微镜观察重组载体的表达和细胞内定他.主要观察指标:NIH3T3细胞转染24h后.利用Leica荧光显微镜观察上述重组载体在细胞中的表达和定位情况.结果:重组质粒经酶切、PCR和测序鉴定正确无误,并在NIH3T3细胞中可获得高量表达.融合蛋白发出的红色和绿色荧光均表明,肌动蛋白在细胞质中呈短丝状弥散分布,Tau蛋白以细胞核为中心呈放射状排列.结论:成功构建了肌动蛋白和Tau蛋白的不同荧光蛋白融合表达载体,并在真核细胞中得到有效表达,这为研究细胞骨架在信号分子移位中的作用提供了一个重要的工具.     

小鼠Foxp3融合蛋白的原核表达及纯化

目的克隆小鼠Foxp3(MFoxp3)基因,构建含该基因的原核表达载体,并表达、纯化出小鼠的Foxp3融合蛋白。方法RT-PCR方法从小鼠淋巴细胞扩增出小鼠Foxp3基因,连入T Easy Vector进行测序,然后将序列正确的小鼠Foxp3基因用酶切的方法从T Easy vector切下,并将其连接到用相同酶切,含有硫氧还蛋白(含6个组氨酸“标签”)的pET 32a( )原核表达载体中构建pET 32a( )-MFoxp3表达载体。用IPTG诱导转化pET 32a( )-MFoxp3表达载体的大肠杆菌BL21(DE3),并以镍螯合层析法纯化MFoxp3融合蛋白。结果经RT-PCR成功地克隆了1,290 bp的小鼠Foxp3基因,测序正确后转化大肠杆菌原核表达载体pET 32a( ),重组质粒在BL21(DE3)中成功表达出分子质量约为63 kD的融合蛋白,运用Ni-NTA方法纯化出目的蛋白,纯化后的蛋白纯度达80%,并用Western Blotting检测蛋白的灵敏度和特异性。结论构建了小鼠Foxp3的融合蛋白原核表达载体并成功表达与纯化出小鼠Foxp3的融合蛋白。     

哺乳动物极性蛋白mInscuteable-C末端肽段/GST融合蛋白的原核表达与纯化

目的:构建哺乳动物极性蛋白mInscuteable C末端257～532位氨基酸结构域与谷胱甘肽巯基转移酶(GST)的融合蛋白GST-mInsc 257～532的原核表达载体,在大肠杆菌中表达并纯化该融合蛋白。方法:将已经构建好的mInsc 257～532位氨基酸序列克隆至原核表达载体pGEX-4T中,构建重组的质粒pGEX-4T/mInsc 257～532;将重组质粒转化感受态细菌BL21,异丙基-β-D-硫代吡喃半乳糖苷(IPTG)诱导表达GST蛋白;经谷胱甘肽-琼脂糖球珠分离纯化;产物经SDS-PAGE电泳及Western Blot鉴定。结果:获得高表达及纯化的pGEX-4T/mInsc 257～532融合蛋白。结论:成功构建重组pGEX-4T/mInsc 257～532原核表达载体;诱导表达pGEX-4T/mInsc 257～532融合蛋白并纯化。     

PTEN基因重组慢病毒的构建

目的:构建PTEN基因重组慢病毒,转染真核细胞Ishikawa并检测PTEN基因在真核细胞内的表达.方法:分子克隆重组人PTEN基因与含有CMV启动子和绿色荧光蛋白(GFP)的慢病毒载体PLIG,PCR筛选阳性克隆,测序鉴定.将重组子PLIG-PTEN和包装质粒共转染包装细胞293T细胞,包装产生慢病毒,感染子宫内膜癌细胞株Ishikawa,观察慢病毒表达载体所携带的GFP基因在细胞内的表达,使用RT-PCR和western-blot检测PIEN基因在细胞内的表达水平.结果:PCR和测序证实,成功克隆慢病毒载体PLIG-PTEN,包装慢病毒,感染真核细胞Ishikawa后48 h,观察到绿色荧光的广泛表述并检测出宿主细胞内表达的PTENmRNA成功表达PTEN蛋白.结论:本实验成功地构建了人PTEN基因慢病毒载体,并观察到PTEN基因在真核细胞中的成功表达.     

可生物素化H-2K~d-BSP融合蛋白的原核表达和纯化

目的构建可生物素化的H-2Kd-BSP融合基因的表达载体,原核表达H-2Kd-BSP融合蛋白,以制备H-2Kd-肽四聚体。方法采用RT-PCR技术从小鼠SP2/0细胞中克隆小鼠MHC-Ⅰ类分子H-2Kd基因的胞外区,拼接上依赖BirA酶的可生物素化序列(BSP)后,插入pET-22b高效表达载体多克隆位点,诱导表达后对表达产物进行纯化,用Western印迹法分析鉴定纯化融合蛋白。结果成功构建pET-H-2Kd原核表达载体,测序证实H-2Kd-BSP融合基因序列正确。pET-H-2Kd原核表达载体可在大肠杆菌BL21中高效诱导表达H-2Kd-BSP融合蛋白,表达量占菌体总蛋白的36%,主要以包涵体形式表达;经反复洗涤纯化,纯化蛋白纯度可达90%以上。纯化蛋白可被H-2Kd分子特异性单克隆抗体SF1-1.1所识别。结论可生物素化H-2Kd-BSP融合蛋白的原核表达和纯化为进一步制备H-2Kd-肽四聚体奠定了实验基础。     

HCV核心蛋白C末端片段在大肠杆菌中的表达及抗原性分析

[目的]构建含HCV核心蛋白近C端片段的原核表达载体，纯化融合蛋白，探讨表达产物的抗原性。[方法]PCR扩增HCV核心蛋白近C端片段基因，克隆入原核表达载体pGEX-4T-2，诱导表达、提取包涵体纯化日的蛋白；ELISA分析该融合蛋门的抗原性。[结果]正确构建HCV核心蛋白片段基因的原核表达质粒，目的蛋白质在大肠杆菌中获到高效表达，并得到有效纯化；ELSA结果显示该融合蛋白具有良好的抗原性。[结论]该HCVC融合蛋白检测HCV感染患者血清具有良好的特异性和敏感性，可望提高HCV抗体检测试剂盒的检出率。     

GRIM-19及其截断体原核表达载体的构建及表达与纯化

目的构建GRIM-19及其截断体原核表达载体,在大肠杆菌中诱导表达并纯化融合蛋白。方法用RT-PCR法从HeLa细胞中扩增出带BamHⅠ、XhoⅠ酶切位点的GRIM-19及其截断体基因片段,将GRIM-19及其截断体基因片段克隆到pGEX-4T-3原核表达载体上,在大肠杆菌中诱导表达GST-GRIM-19及其截断体融合蛋白,用Glutathione Sepharose 4B纯化,纯化后蛋白经Western-blot鉴定。结果 pGEX-4T-3-GRIM-19及其截断体原核表达载体构建正确,并在大肠杆菌中成功诱导表达,IPTG诱导以浓度0.5mM,时间2h为宜,且通过Glutathione Sepharose4B成功纯化到融合蛋白。结论成功构建GRIM-19及其截断体原核表达载体,诱导表达并纯化GST-GRIM-19及其截断体融合蛋白。     

人Tamm-Horsfall片段蛋白的表达及单克隆抗体的制备和鉴定

目的 构建人Tamm-Horfall蛋白（THP）抗原决定簇的原核表达载体,表达纯化重组人Tamm-Horfall片段蛋白并制备单克隆抗体.方法 将人Tamm-Horfall蛋白片段cDNA克隆至原核表达载体pET28a,经大肠杆菌表达、纯化,获得的Tamm-Horfll蛋白片段免疫小鼠,取其脾淋巴细胞与sp2/0细胞融合,制备能产生THP蛋白单克隆抗体的杂交瘤细胞株,进一步采用Western blot、ELISA、免疫组化等技术对制备的单克隆抗体进行鉴定.结果 原核表达重组质粒在大肠杆菌中能高效表达THP蛋白抗原决定簌的蛋白片段,用纯化的THP蛋白片段制备了鼠抗THP单克隆抗体.结论 成功制备了9株THP单克隆抗体,为进一步研究THP蛋白的分布、结构、功能及检测试剂盒的研发奠定了基础.     

mica基因的克隆及其在原核系统中的表达

本研究构建mica基因原核表达系统并纯化MICA蛋白。利用外周血标本提取RNA,经RT-PCR获取mica基因cDNA。将mica cDNA经TOPO克隆连接构建克隆载体,然后将克隆重组载体和原核表达载体pET-28a经双酶切后进行连接构建重组表达载体,进而转染宿主菌E.coliBL21DE3进行表达。利用亲和层析的Ni-NTASpin纯化重组的MICA蛋白。结果表明:带有重组质粒pET-28a-mica的宿主菌经IPTG诱导表达后,以可溶性形式大量表达重组的MICA蛋白,经Ni-NTA Spin纯化后得到重组的MICA蛋白。结论:本研究构建了mica基因原核表达系统并纯化了MICA蛋白,为探讨MICA与移植免疫的关系奠定了基础。     

α-SEA型地中海贫血标志蛋白zeta链蛋白的克隆表达与鉴定

目的克隆zeta链蛋白基因并在大肠杆菌中表达,经纯化与鉴定,为建立α-SEA型地中海贫血的免疫学筛查方法提供特异性抗原。方法从经处理的K562细胞中提取总RNA,采用RT-PCR技术反转录并将其克隆到pET-21a( )载体中,测序验证。融合蛋白在大肠杆菌中表达,采用Probond树脂柱纯化融合蛋白,用WesternBlotting和ELISA鉴定。结果成功构建了融合表达载体pET-zeta,融合蛋白得到可溶性表达及纯化,经Westernblotting和商品ELISA试剂盒鉴定显示重组蛋白为zeta链蛋白。结论克隆表达并获得了纯化zeta链蛋白,为地中海贫血的免疫筛选方法的建立提供了抗原。     

Plasma protein turnover and tissue exchange; influence of dietary protein and protein depletion

The rate of plasma protein turnover is more rapid in dogs receiving adequate dietary protein than when a diet devoid of protein is fed. Both albumin and combined globulins are involved in this change. The difference in turnover is reflected in a total protein half-life of 4.8 days with protein feeding versus 7.8 days without protein in the diet and in the metabolism of 1.0 and 0.65 gm. per kilogram of body weight per day on the respective diets. Additions of dietary protein from 10 to 30 per cent caused no further increase in the rate of plasma protein turnover. With protein depletion due to plasmapheresis and a very low protein diet there is evidence of reduced protein metabolism as indicated by nitrogen retention as well as a reduction in total plasma protein breakdown and interchange of isotope between plasma and tissue proteins. Following introduction of labeled plasma protein into the circulation the net amount of isotope transferred to tissues has been computed from the difference between total plasma protein breakdown and combined C¹⁴ excretion in urine and expired air. In animals receiving adequate dietary protein, tissue transfer amounts to 70 per cent of the total lost from the plasma proteins each day while the percentage rises to 85 in depleted dogs deprived of protein. In dogs with both plasma and tissue proteins labeled it can be estimated that, under conditions of protein feeding, an amount of C¹⁴ approximately equal to that lost from the plasma must recycle to account for the observed decrease in Apparent plasma protein turnover rate, (t½ of 15 versus 5 days). Without protein in the diet the isotope contribution of the tissues to the maintenance of plasma protein levels must be as great as or greater than that transferred in the opposite direction.     

腺苷酸活化蛋白激酶与骨骼肌蛋白质降解

背景:机体运动时骨骼肌收缩,ATP被大量消耗,产生大量腺苷一磷酸,导致腺苷酸活化蛋白激酶的激活。目的:综述不同运动过程中腺苷酸活化蛋白激酶活性的变化,以及腺苷酸活化蛋白激酶对骨骼肌蛋白质降解的研究成果。方法:检索中国期刊网、维普期刊数据库、www.ncbi.nlm.nih.gov/pubmed和http://highwire.stanford.edu/网站与腺苷酸活化蛋白激酶、运动、蛋白质降解研究相关的文章。并对腺苷酸活化蛋白激酶的结构与作用,不同运动过程中腺苷酸活化蛋白激酶活性的变化,以及腺苷酸活化蛋白激酶升高对骨骼肌蛋白质降解的内容进行分析综述。结果与结论:共纳入相关文献35篇。本文综述了腺苷酸活化蛋白激酶的结构、作用的研究进展;在抗阻运动和中到大强度的周期运动中,腺苷酸活化蛋白激酶活性都可能升高,而在小强度周期运动过程中腺苷酸活化蛋白激酶活性可能不升高;腺苷酸活化蛋白激酶的活化可能对骨骼肌蛋白质的降解有促进作用。     

腺苷酸活化蛋白激酶与骨骼肌蛋白质降解

背景：机体运动时骨骼肌收缩,ATP被大量消耗,产生大量腺苷一磷酸,导致腺苷酸活化蛋白激酶的激活。目的：综述不同运动过程中腺苷酸活化蛋白激酶活性的变化,以及腺苷酸活化蛋白激酶对骨骼肌蛋白质降解的研究成果。方法：检索中国期刊网、维普期刊数据库、www.ncbi.nlm.nih.gov/pubmed和http：//highwire.stanford.edu/网站与腺苷酸活化蛋白激酶、运动、蛋白质降解研究相关的文章。并对腺苷酸活化蛋白激酶的结构与作用,不同运动过程中腺苷酸活化蛋白激酶活性的变化,以及腺苷酸活化蛋白激酶升高对骨骼肌蛋白质降解的内容进行分析综述。结果与结论：共纳入相关文献35篇。本文综述了腺苷酸活化蛋白激酶的结构、作用的研究进展;在抗阻运动和中到大强度的周期运动中,腺苷酸活化蛋白激酶活性都可能升高,而在小强度周期运动过程中腺苷酸活化蛋白激酶活性可能不升高;腺苷酸活化蛋白激酶的活化可能对骨骼肌蛋白质的降解有促进作用。     

Specificity of protein C and protein S assays

Summary Specific tests for the measurement of protein C antigen and activity and protein S antigen are used in the clinical laboratory for the routine diagnosis of hereditary protein C and protein S deficiency. The performance of these tests is reviewed and discussed. Special attention is paid to the application of these tests for the analysis of patients on oral anticoagulant therapy. Presented at the ‘2nd International Symposium on Standardization and Quality Control of Coagulation Tests: Implications for the Clinical Laboratory’, Rome, September 28–29, 1989.     

Acquisition of inhibitor-sensitive protein kinases through protein design.

Protein phosphorylation is the major post-translational modification used by eukaryotic cells to control cellular signaling. Protein kinases have emerged as attractive drug targets because heightened protein kinase activity has been associated with several proliferative diseases, most notably cancer and restenosis. Until now, it has been very difficult to confirm the utility of protein kinases as inhibitor targets because very few small molecules that selectively inhibit one particular kinase are known. Discovery of highly specific kinase inhibitors has been slow because the protein family contains approximately 2000 members, all of which share a conserved active site fold. Recent work in several laboratories has sought to circumvent the problem of kinase structural degeneracy by engineering drug sensitivity into Src family tyrosine kinases and mitogen-activated protein kinases through site-directed mutagenesis. By introducing a unique non-naturally occurring amino acid into a conserved region of the enzyme's binding site, a target protein kinase can be rapidly sensitized to a small molecule. Introduction of the engineered kinase into a cell line or animal model should greatly expedite the investigation of protein kinase inhibition as a viable drug treatment. The purpose of this review is to summarize these recent advances in protein kinase drug sensitization.     

Human erythrocyte protein 4.1 is a phosphatidylserine binding protein.

The aminophospholipids phosphatidylethanolamine (PE) and phosphatidylserine (PS) are the major phospholipids contained in the cytoplasmic leaflet of the human erythrocyte (RBC) plasma membrane and are largely confined to that leaflet over the entire RBC lifespan. In particular, PS, which comprises approximately 13% of total RBC membrane phospholipids, is normally restricted entirely to the cytoplasmic leaflet. However, molecular mechanisms that regulate this asymmetric distribution of phospholipids are largely unknown. We examined elliptocytic RBCs that completely lacked protein 4.1 (HE [4.1 degrees]), but contained normal amounts of all other peripheral membrane proteins, and found approximately 10% of total membrane PS was accessible in the exoplasmic leaflet of these membranes. Inside out vesicles (IOVs) derived from HE [4.1 degrees] RBCs bound fewer PS liposomes than did IOVs derived from normal RBCs. Normal IOVs that were depleted of proteins 2.1 (ankyrin), 4.1, and 4.2 bound fewer PS liposomes similar to HE [4.1 degrees] IOVs, and repletion with protein 4.1 restored PS liposome binding to control levels. Addition of purified protein 4.1 to PS liposomes resulted in saturable binding with the extent of binding being proportional to the liposome PS content. Our data suggests that human RBC protein 4.1 is a PS binding protein and may be involved in the molecular mechanisms that stabilize PS in the cytoplasmic leaflet of the human RBC plasma membrane.