一个新的蛋白激酶基因DYRK3的克隆及其特征分析

目的分离一个与人的蛋白激酶ＤＹＲＫ２高度同源新的蛋白激酶的全长ｃＤＮＡ，并推测其分类和功能。方法应用与人的蛋白激酶ＤＹＲＫ２高度同源的３′端部分ｃＤＮＡ序列为探针，筛选ｃＤＮＡ文库和ｇＤＮＡ文库，并进行氨基酸序列同源性分析和ＦＩＳＨ定位。结果从人的骨骼肌ｃＤＮＡ文库和睾丸ｃＤ－ＮＡ文库各分离到一个新的蛋白激酶的全长ｃＤＮＡ。骨骼肌来源的ｃＤＮＡ编码５８８个氨基酸的蛋白质，睾丸来源的ｃＤＮＡ编码５６８个氨基酸的蛋白质，前者第２７个氨基酸以后的序列与后者第７个氨基酸以后的序列完全一致。结论推测这两个ｃＤＮＡ是同一基因在骨骼肌组织和睾丸组织中的不同剪接本。由于该基因与人的ＤＹＲＫ２高度同源，故称之为ＤＹＲＫ３基因。ＤＹＲＫ３与丝氨酸／苏氨酸蛋白激酶酵母Ｙａｋ１，人和果蝇的Ｍｎｂ，人的Ｃｌｋ１等有较高的同源性，也与人的Ｃｄｋ２等其它丝氨酸／苏氨酸激酶有同源性。作者认为ＤＹＲＫ３是属于丝氨酸／苏氨酸蛋白激酶ＣＭＧＣ组Ｃｌｋ家族新的一员。该基因定位在１ｑ３２。     

牛IgG Fc受体Ⅲ的分子克隆和序列分析

目的 研究牛ＩｇＧＦｃ受体的结构与功能的关系。方法 在构建了牛肺巨噬细胞ＣＤＮＡ文库的基础上,用ＰＣＲ方法获得了码牛ＩｇＧＦｃ受体Ⅲ的全长编码基因。结果 通过分子克隆和序列分析,发现其编码基因为５０７ｂｐ,共编码１６８个氨基酸,其中含有信号肽序列,穿膜区和胞内结构域以及３个Ｎ－连接糖基化位点。与ＣＯＬＬＩＮＳ等克隆的ｂｏＦｃγＲⅢ相比,在它的胞外区中缺失了８２个氨基酸,仅有一个胞外结构域。结论 我     

抗人RBC血型B抗原双价小分子抗体基因的构建与表达

目的： 分离抗人红细胞血型Ｂ抗原单克隆抗体（ｍＡｂ） ５Ｄ１２ 可变区基因, 构建并表达其双价小分子抗体（ｄｉａｂｏｄｙ） 融合蛋白, 为用原核细胞生产抗血型Ｂ抗原工程抗体进行基础研究。方法： 设计合成抗体重、轻链可变区引物, 通过加端ＰＣＲ技术, 在ｍＡｂ ５Ｄ１２ ＶＨ 和ＶＬ基因两端引入连结短肽和适当的限制性酶切位点,体外连接构建５Ｄ１２ ｄｉａｂｏｄｙ 基因, 并将其克隆入融合表达载体ｐＧＥＸ４Ｔ２ 中, 在Ｅ－ｃｏｌｉ ＴＧ１ 中表达。运用ＰＣＲ和双脱氧核苷酸链末端终止法分析其核苷酸序列。结果： ＤＮＡ 序列分析表明, ５Ｄ１２ ｄｉａｂｏｄｙ 基因全长为６９９ｂｐ;其中ＶＨ 长３５１ｂｐ , 编码１１７ 个氨基酸; ＶＬ 长３２４ｂｐ , 编码１０８ 个氨基酸, 两者以五肽连接头相连; 重组体表达产物经ＳＤＳＰＡＧＥ显示, ＧＳＴ５Ｄ１２ ｄｉａｂｏｄｙ 表达产物的相对分子质量（ Ｍｒ） 为５１ ０００ 左右, 与预期结果相符。光密度扫描结果表明, ＧＳＴ５Ｄ１２ ｄｉａｂｏｄｙ 融合蛋白占菌体总蛋白的２４－６％ , 表达产物主要以不溶性的包涵体形式存在。结论： 成功地构建并表达了５Ｄ１２ 双价小分子抗体基因, 在原核细胞中获得较高水平     

直接从中国人胎肝染色体DNA中克隆粒细胞集落刺激因子（G－CSF）外显子及其在大肠杆菌中的高效表达

利用聚合酶链反应（ＰＣＲ）技术，直接从正常人胎肝染色体ＤＮＡ库中分离克隆了中国人粒细胞集落刺激因子（ｃ－ＣＳＦ）外显子，全长５３７ｂｐ，它包括除信号肽氨基酸外的所有编码区，为了使克隆的Ｇ－ＣＳＦ外显子在大肠杆菌中高效表达，对其５’端进行了修饰，去除第１个编码Ｔｈｒ的密码子，在不改变氨基酸的前提下，变换为ＡＴ丰富的密码子；并将某些密码子换成大肠杆菌喜用的密码子。对于每段目的ＤＮＡ所进行的２次独立的ＰＣＲ反应所获得的产物分别进行了核苷酸序列测定。结果完全一致，证明所克隆的Ｇ－ＣＳＦ外显子的序列是可靠的，与国外发表的Ｇ－ＣＳＦ外显子序列相比，未发现变异。将上述人Ｇ－ＣＳＦ外显于基因插入ｐＢＶ２２０表达载休，构建了ｐＢＶ２２０／Ｇ－ＣＳＦ质粒，将其转化入ＤＨ５ａ菌，ＳＤＳ－ＰＡＧＥ表明其表达量约占菌体总蛋白量的２０％，用依赖性细胞系ＮＦＳ－６０进行测定，活性为５ｘ１０ｖＩＵ／Ｌ。     

中国庚型肝炎病毒河南株非结构基因（NS）3区cDNA的克隆 …

目的 为了研究中国庚型肝炎病毒（ＨＧＶ）非结构（ＮＳ３）区基因结构特征。方法 利用逆转录－半巢式－聚合酶链反应从河南１份ＨＧＶ ＲＮＡ阳性血清获得覆盖ＨＢＶ ＮＳ３全长ｃＤＮＡ的４个片段，并克隆到ｐｃＤＮＡⅡ载体中，采用Ｓａｎｇｅｒ双脱氧末端终止法测定全部ｃＤＮＡ序列。结果 发现克隆到的包括ＨＢＶ ＮＳ３区在内的ｃＤＮＡ序列和度为２１３７个核苷酸，编码７１１个氨基酸。与国内外已测定的５株全序列的相     

中国广西狂犬病毒野毒株（CGX89—1株）糖蛋白基因核…

本报告了中国广西狂犬病毒野毒株（ＣＧＸ８９－１株）糖蛋白基因ｃＤＮＡ的核苷酸序列及其推导的氨基酸序列。ＣＧＸ８９－１株的糖蛋白基因从起始密码ＡＴＧ到终止密码ＴＡＡ共有１５７５个核苷酸残基，可编码形成５２４个氨基酸残基的多肽链，经修饰后形成具有５０５个氨基酸残基构成的狂犬病毒糖蛋白。ＣＧＸ８９－１株的糖蛋白基因和核苷酸组成分别为：Ａ占２７．１１％，Ｔ占２６．２９％，Ｃ占２１．９７％和Ｇ占２４．６３％     

编码人分化抗原5C5全长cDNA的克隆及功能初探

目的 编码５Ｃ５分化抗原全长ｃＤＮＡ的克隆及功能探索。方法 构建人活化Ｂ细胞株３Ｄ５细胞的λｇｔ１１ ｃＤＮＡ文库，以核苷酸杂交法从ｃＤＮＡ文库中筛选阳性克隆、作核苷酸序列分析，编码蛋白质氨基酸序列的亲疏水分析，Ｎｏｒｔｈｅｒｎ ｂｌｏｔ测５Ｃ５ ｍＲＮＡ转录本长度，用ＲＴ－ＰＣＲ检测５Ｃ５ ｍＲＮＡ在不同细胞株的表达，观察单抗５Ｃ５－Ｇ１对３Ｄ５细胞增殖的影响。结果 从人活化Ｂ细胞株３Ｄ５的λｇ     

从人活化B细胞株3D5细胞λgtll cDNA文库筛选到的1529bp cDNA的核苷酸序列分析

对用单抗５Ｃ５和单抗５Ｃ５－Ｇ１的混合物从３Ｄ５细胞λｇｔｌｌｃＤＮＡ文库筛选到的７个阳性ｃＤＮＡ克隆中的１个（３Ｄ５－５）进行了核苷酸序列分析。由于３Ｄ５－５ｃＤＮＡ长１．６ｋｂ左右，不能直接测序，故先依测序用质粒ｐＢＳｃｒｉｐｔ－ＫＳ多克隆位点中的内切酶点行单酶切，经电泳分析画出测序用的物理图谱，再用相应内切酶行单酶酶切。藉低熔点琼脂糖回收各个片段。带质粒ｐＢＳｃｒｉｐｔ－Ｋ５的大片段经直接自身环化，小片段与质粒载体ｐＢＳｃｒｉｐｔ－ＫＳ重组，构建测序用的亚克隆。用双链双脱氧末端终止法测各亚克隆的核苷酸序列，再拚接出全长为１５２９ｂｐ的３Ｄ５－５ｃＤＮＡ全长序列。与国际基因库资料比较，未见有相同的序列。此ｃＤＮＡ中有一个长４６５ｂｐ（从５４０ｂｐ－１００４ｂｐ）的ＯＲＦ，编码１５４个氨基酸的蛋白质。此蛋白质中有二个疏水区（第１～３４位氨基酸及第７９～１０９位氨基酸），提示它可能属Ⅰ类穿膜蛋白。     

人单核细胞趋化蛋白－1（MCP－1）基因的PCR扩增、克隆及序列分析

本文报道用植物血凝素（ＰＨＡ）诱导健康人外周血单个核细胞（ＰＢＭＣ，包括单核细胞和淋巴细胞），提取细胞总ＲＮＡ，反转录合成ｃＤＮＡ第一链，再以其为模板进行ＰＣＲ，得到了编码成熟单核细胞趋化蛋白－１（ＭＣＰ－１）的ｃＤＮＡ。该ｃＤＮＡ用ＥｃｏＲＩ、ＢａｍＨＩ双酶切后，回收含ＭＣＰ－１基因的长约２８０ｂｐ的ＤＮＡ片段，插入到经ＥｃｏＲＩ、ＢａｍＨＩ双酶切的ｐＵＣ１９载体中，进行序列分析。结果表明，ＭＣＰ－１中第１２个氨基酸的编码序列与国外报道的不同。由ＴＧＴ变成了ＴＧＣ，但编码相同的氨基酸即半胱氨酸，其余的编码序列则完全相同，说明ＭＣＰ－１的基因型可能存在着多态性。     

新生血管抑制分子IP—10／Crg—2的cDNA克隆及序列鉴定

目的： 拟获得编码ＩＰ１０ （ＩＦＮγｉｎｄｕｃｉｂｌｅ ｐｒｏｔｅｉｎ１０） 和Ｃｒｇ２ （ｃｙｔｏｋｉｎｅ ｒｅｓｐｏｎｓｉｖｅ ｇｅｎｅ２） 的ｃＤＮＡ 序列。方法： 针对ＩＰ１０ 和Ｃｒｇ２ 的ｃＤＮＡ序列设计相应引物， 通过反转录ＰＣＲ技术， 分别从用ＩＦＮγ及ＴＮＦα处理的人成纤维细胞及Ｂａｌｂ／ｃ 小鼠肝脏中， 扩增出编码ＩＰ１０ 和Ｃｒｇ２ 的全基因序列， 并将其克隆入载体ｐＵＣ１９及ｐＧＥＭ３Ｚｆ （＋ ） 中， 通过酶切及序列测定鉴定重组载体。结果： 经序列测定证实， 重组载体含有正确地分别编码ＩＰ１０ 及Ｃｒｇ２ 的ｃＤＮＡ序列。结论： 获得的阳性克隆分别含有３０６ｂｐ 和３１４ｂｐ 的重组片段， 为进一步对其生物学活性和配体进行研究奠定了基础。     

Molecular cloning, reconstruction and expression of the gene encoding the alpha-chain of the bovine CD8--definition of three peptide regions conserved across species.

We report the cloning of a cDNA encoding the alpha-chain of the bovine CD8 (BoCD8 alpha). A bovine thymus cDNA library was hybridized at low stringency with a human CD8 alpha cDNA clone. The first round of screening of 5 x 10(4) independent colonies yielded 12 clones containing incomplete BoCD8 alpha genes. Two further rounds of colony hybridization were conducted, each using as a probe the 5' fragment from the longest BoCD8 alpha clone previously isolated. The final screening yielded a clone containing a 2 kilobase (kb) insert. We mapped and sequenced the 2 kb BoCD8 alpha clone and compared it with the published sequences of the genes encoding the human, mouse and rat CD8 alpha. Sequence analysis confirmed that the clone under study encoded the BoCD8 alpha. The overall similarity of the BoCD8 alpha coding region with the human CD8 alpha coding sequence is 74.7% at the nucleotide level and 62.1% at the protein level. Lower levels of similarity are found with the mouse and rat CD8 alpha. Interestingly, three separate highly homologous regions are clearly defined at the peptide level in bovine versus human and mouse versus rat comparisons. Two of the regions are highly conserved among all species analysed, while the most 5' region is not. We speculate that the latter region may contain the binding site of CD8 alpha to the alpha 3 domain of major histocompatibility complex (MHC) class I molecules. Sequence analysis showed that the 2 kb BoCD8 alpha clone contains an incomplete coding region, i.e. lacks six bases corresponding to the first two amino acids of the leader region. To allow efficient translation and processing of the BoCD8 alpha gene, we constructed a chimeric gene containing the coding sequence of the BoCD8 alpha clone and synthetic sequences corresponding to the first two amino acids of the human CD8 alpha leader sequence. The chimeric gene was subcloned in the pKSV10 expression vector. The pKSV10-BoCD8 alpha construct is efficiently expressed both transiently in COS cells and stably in L cells, as determined by Northern blot and by FACS analysis, using the ILA-51 monoclonal antibody to BoCD8 alpha. The latter result formally proves that the ILA-51 antibody does indeed recognize the product of the BoCD8 alpha gene, as previously suggested on serological grounds.     

Sequence of the bovine CD44 cDNA: comparison with human and mouse sequences

CD44 is a cell-surface glycoprotein involved in leukocyte adherence, T-cell activation and lymphocyte homing. We have isolated and sequenced a cDNA clone which encodes for bovine CD44. The predicted amino acid sequence of bovine CD44 has an overall high similarity with that of human and mouse CD44, 79.5 and 73.2%, respectively. In all three species, CD44 has a similar transmembrane region and cytoplasmic tail. In addition, all of the cysteine residues and a majority of the putative N-linked glycosylation sites in the extracytoplasmic domain are conserved between bovine, human and mouse. All three species have an area of low interspecies similarity within the extracytoplasmic domain. This area has a similarity of 34% between bovine and human, 27% between bovine and mouse, and 35% between human and mouse. The location of this area of low similarity is conserved between species.     

Molecular characterisation of the tammar wallaby (Macropus eugenii) CD3 epsilon chain cDNA.

The cDNA encoding the epsilon chain of the tammar wallaby CD3 complex (CD3epsilon) was isolated by PCR. This is the first CD3 component to be cloned in a marsupial. The tammar wallaby cDNA coding region was 61.7 and 63.0% identical to the human and mouse cDNA coding sequences, respectively. Similarly, the predicted amino acid sequence was 56.5 and 52.9% identical to the human and mouse sequences. When compared with other known CD3epsilon peptide sequences, the most conserved region of the tammar wallaby CD3epsilon chain peptide was the cytoplasmic domain and the least conserved was the extracellular portion. Phylogenetic reconstruction based on the deduced amino acid sequence placed the tammar wallaby sequence in its expected position outside of all the eutherian mammals.     

Chicken CD14, unlike mammalian CD14, is trans-membrane rather than GPI-anchored

A cDNA encoding the chicken homologue of the human myelomonocytic differentiation antigen, CD14, was cloned by RT-PCR from chicken bone marrow cell RNA, using oligonucleotide primers based on the predicted cDNA sequence. The cloned chicken CD14 (chCD14) cDNA encodes an open reading frame of 465 amino acids (aa), with 31-34% aa identity to mouse, bovine and human (hu) CD14. As in mouse and man, chCD14 is a leucine-rich protein. In mammals, CD14 is a GPI-anchored protein. Protein structure analysis suggested that chCD14, by contrast, was potentially a trans-membrane protein. The predicted aa sequence comprises an extracellular domain of 417 aa, followed by a 23-aa trans-membrane segment, and a 25-aa intracytoplasmic region, the latter containing no obvious signalling motifs. COS-7 cells were transfected with p3XFLAG-CMV-8::chCD14 or pCDM8::huCD14, incubated with or without PI-PLC and stained with anti-FLAG or anti-huCD14 antibody respectively. PI-PLC cleaved huCD14 but not chCD14, suggesting that chCD14 is not GPI-anchored. Real-time quantitative RT-PCR analysis revealed that chCD14 mRNA was expressed in most lymphoid and non-lymphoid tissues, except muscle. ChCD14 mRNA was also expressed in most cells examined but strongly expressed in chicken peripheral blood monocyte/macrophages and KUL01+ splenocytes.     

Molecular cloning characterization and expression of porcine immunoreceptor SIRPalpha

SWC3 is a porcine CD that has been the reference marker of myeloid lineage. It is expressed in every myelomonocytic cell from early bone marrow precursors. We have identified the molecule recognized by anti-SWC3 antibodies as a member of the signal-regulatory proteins (SIRPs)alpha family. Here, we describe the cloning of a cDNA coding for a porcine SIRPalpha protein. The sequence is 2470 nucleotides long and contains an open reading frame encoding a 507 amino acid sequence. The predicted polypeptide was composed of a 30 amino acids putative signal peptide, a 342 amino acid extracellular region, a 23 amino acid transmembrane segment and a 112 amino acid cytoplasmic domain. Analysis of the sequence reveals a high degree of homology with known SIRPs in other species, being easily identified the three extracellular Ig type domains and two cytoplasmic ITIM motifs characteristic of this molecule. The gene coding for porcine SIRPalpha has been mapped to porcine chromosome 17, in a region syntenic to the human chromosome 20 where SIRP genes have been mapped. During the analysis of SIRP gene expression in tissues by RT-PCR, we noticed the existence of a shorter mRNA, and cloned the corresponding cDNA. This coded for a splicing variant of SIRPalpha that lacked the two membrane proximal Ig domains. In transfection experiments, we have been able to show that anti-SWC3 antibodies recognize both forms of the molecule, mapping the SWC3 epitopes to the N-terminal IgV type domain.     

Structural homologies between RNA gene segments 10 and 11 from UK bovine, simian SA11, and human Wa rotaviruses

The nucleotide sequences of gene segments 10 and 11 from UK bovine rotavirus have been determined. Gene 10 is 751 nucleotides long and contains a single long open reading frame capable of coding for a protein of 175 amino acids. When compared with the published data for gene 10 of the simian rotavirus SA11 and human Wa strains it was found to be more closely related to the SA11 structure (92% nucleotide sequence homology; 97% amino acid sequence homology) than to the human Wa structure (84% nucleotide, 86% amino acid sequence homology). All three strains have two potential N-glycosylation sites in the hydrophobic N terminus of the gene 10 protein. Gene 11 from UK bovine rotavirus is 667 nucleotides long with a single long open reading frame capable of coding for a protein of 198 amino acids. When compared with the published sequence of gene 11 from the human rotavirus Wa, the UK bovine rotavirus gene 11 was found to be one nucleotide longer in the 5'-noncoding region and three nucleotides longer in the coding region. The nucleotide sequence homology was 86%. The predicted proteins coded by segment 11 in UK and Wa rotaviruses are both rich in serine and threonine (23%) and very hydrophilic, but differ appreciably in amino acid sequence (83% homology).     

Bovine GM-CSF: molecular cloning and biological activity of the recombinant protein

The lymphokine granulocyte-macrophage colony-stimulating factor (GM-CSF) mediates the growth and differentiation of granulocytes and macrophages from bone marrow progenitors, and regulates biological functions expressed by mature cells of these lineages. In order to isolate a bovine GM-CSF cDNA, a cDNA library, generated from the BT2 bovine T cell line, was screened with a human GM-CSF cDNA probe. A cDNA clone was isolated with an insert of 783 bp, that would encode a protein of 143 amino acids, with a predicted mol. wt of 16,160. Bovine GM-CSF exhibits a high degree of sequence homology with mouse and human GM-CSF at both the nucleotide and amino acid levels. Comparison of GM-CSF amino acid sequences from the three species indicates that the bovine GM-CSF precursor contains a putative 17 amino acid signal sequence, cleavage of which would yield a 14,250 mol. wt protein. The cDNA was inserted into a mammalian expression vector and transfected into COS-7 monkey kidney cells. Biologically active bovine GM-CSF was secreted as judged by a bovine bone marrow proliferation assay. Bovine GM-CSF was weakly active in both human and mouse bone marrow proliferation assays. In contrast, human GM-CSF was weakly active on bovine but not murine mouse bone marrow cells and mouse GM-CSF was only active on murine bone marrow cells.     

Recognition of CD52 allelic gene products by CAMPATH-1H antibodies.

Cloning of the CD52 from a B-lymphocyte tumour cDNA library revealed two closely related sequences differing only at two amino acids C-terminal to the proposed point of glycosylphosphatidylinositol (GPI)-linkage. When transfected into CHO cells only one of these sequences gave high-level expression of the antigen recognized by the prototypic anti-CD52 antibody CAMPATH-1 whereas in JURKAT cells good expression levels were obtained with both sequences. Fusion of the sequence from the second sequence to DNA encoding the extracellular domain of CD4 indicated that this sequence was capable of directing GPI linkage. The possible implications for the function of CD52 and serotherapy with anti-CD52 antibodies are discussed.