兔防御素（MCP—1）cDNA的克隆与序列分析

从兔脾脏细胞中分离提取总ＲＮＡ,经反转录ＰＣＲ（ＲＴ－ＰＣＲ）扩增出兔巨嗜细胞阳离子多肽（ＭＣＰ－１）ｃＤＮＡ,插入经ＥｃｏＲ Ｉ和Ｘｂａ Ｉ双酶切的ｐＵＣＤ１９中,构建了党生质粒ｐＵＣＤＥＦ,进行了限制性酶切鉴定和序列分析,结果在扩增出的ｃＤＮＡ２８８个碱基中,在前片段中有一个碱基与发表的兔ＭＣＰ－１ ｃＤＮＡ序列不同,即第１５７位碱基由Ｇ变为Ａ,导致编码的氨基酸由丙氨酸变为苏氨酸。该ｃＤＮＡ全     

家蝇防御素基因的cDNA克隆及序列分析

Defensin is a kind of cationic.inducible antimicrobial peptide found in a large range of living organisms that contributes to host defense by disrupting the cytoplasmic membrane of microorganisms.with their broad antimicrobial spectrum and strong pharmaceutical effects.antimicrobial peptides,including defensins,represent a source of novel antibiotic agents.A novel full-length 430 base pairs cDNA of an insect defensin was cloned using polymerase chain reaction (PCR) from the cDnA library of houseflies(Musca domestica) that had been challenged by E.coli and staphylococcus taincd an NH2-terminal signal sequence(1-22)followed by a propeptide and the mature peptide(53-92),The sequence identity with other insect defensin is between 51% and 73%.The mature peptide,with a predicted molecular weight of 4.0kDa,and pI of 8.69,has 1 negative charged amino acid and 4 positice ones,the putative housefly defensin is characterized by 6 invariant cysteine residues forming 3 disulfide bonds,Cys1-Cys4,Cys2-Cys5 and Cys3-Cys6,These results suggest that the novel full-length cDNA of the defensin gene.Denominated Mdde,has been successfully cloned from houseflies.     

荷斯坦奶牛中性粒细胞β-防御素cDNA的克隆与序列分析

为研发牛β-防御素生物制剂,防治奶牛乳腺炎。根据已发表的牛β-防御素基因序列设计一对引物。收集患乳腺炎奶牛乳静脉血液中性粒细胞,用试剂盒提取总RNA。经RT-PCR扩增牛β-防御素cDNA片段,回收纯化PCR产物,连接pMD18-T载体,转化感受态细胞JM109。在含X-Gal、Amp及IPTG的LB平板上筛选阳性克隆,经菌落PCR及双酶切鉴定后,对目的片段进行测序。结果表明RT-PCR扩增出的cDNA片段碱基数为189bp,含有一个完整的ORF,能编码63个氨基酸的多肽,多肽中含6个保守半胱氨酸残基。用Blast程序进行检索比较,表明扩增序列与GenBank中发表的BNBD-7编码区序列96.3%相同。结果成功克隆出奶牛β-防御素家族的成员BNBD-7基因,为重组牛β-防御素的开发奠定了基础。     

军曹鱼肌生成抑制素基因的克隆与序列分析

肌生成抑制素(Myostation,MSTN)是一种骨骼肌生长的负调控因子,其生物功能主要是抑制骨骼肌的生长。肌生成抑制素的活性降低或丧失,可使肌肉与其他组织的比例大大提高,因此在动物育种和医疗上有很大的潜在应用价值。目前包括鱼类在内的20多种脊椎动物的MSTN cDNA已经得到克隆和测序。本实验依据已知的鱼MSTN cDNA的保守区域设计一对特异引物,利用PCR技术分别从军曹鱼基因组中扩增出一个约1000bp的特异片段和300bp片段,所得目的片段回收纯化,将其酶切产物连接到pMDl8-T克隆载体上,转化入JM109感受态细胞中,挑取阳性克隆进行转化子鉴定,其质粒测序结果与文献报道的一致,证明成功地克隆了军曹鱼肌生成抑制素基因。     

人防御素HNP-1基因在原核系统中的克隆与表达

通过化学合成法制备人防御素 HNP- 1基因 ,并将其构建于带有 GST基因的表达载体中 ,进行融合表达 ,表达融合蛋白可占菌体蛋白的 70 %左右 ,且主要以包含体形式存在。改变培养条件可适当提高可溶性融合蛋白的比例。融合蛋白通过凝胶色谱进行纯化 ,然后经凝血酶切释放出防御素多肽 ,并通过抑菌试验对其活性进行检测。结果显示 ,可能由于分子间的二硫键错配造成了防御素分子构象改变 ,使制备的防御素分子未显示出活性     

大鼠脑谷氨酸脱羧酶基因的cDNA克隆及序列分析

胰岛β－细胞自身抗原蛋白之一是脑中谷氨酸脱羧酶（Ｇｌｕｔａｍｉｃａｃｉｄｄｅｃａｒｂｏｘｙｌａｓｅ,ＧＡＤ,ＥＣ４．１．１．１５）同源物。以双链ｃＤＮＡ为模板,用ＰＣＲ方法快速克隆了Ｗｉｓｔａｒ大鼠脑ＧＡＤ基因的ｃＤＮＡ,将此包括编码５９３个氨基酸的全长ＤＮＡ片段重组入ｐＵＣ质粒并用双脱氧末端终止法测定了全部序列,证明其全长为１７７９ｂｐ．经比较发现Ｗｉｓｔａｒ大鼠脑与Ｒｕｓｓｅｌｌ报导的大鼠脑ＧＡＤ基因序列,有一处碱基的差别,但并不涉及氨基酸的改变。同时还对用ＰＣＲ扩增长片段ＤＮＡ进行了方法学上的探讨。     

花生防御素基因的克隆及原核表达

定基础.     

编码日本梨树花粉类植物防御素蛋白(PDN1)的cDNA核苷酸序列

1　Ｓｏｕｒｃｅ　ＴｈｉｓｃＤＮＡｉｎｓｅｒｔｉｓｆｒｏｍａｓｉｎｇｌｅｃｌｏｎｅｏｆｐｏｌｌｅｎｃＤＮＡｌｉｂｒａｒｙｏｆＪａｐａｎｅｓｅＰｅａｒ(Ｐｙｒｕｓｐｙｒｉ ｆｏｌｉａ) .2　Ｎａｍｅａｎｄｄｅｓｃｒｉｐｔｉｏｎ　ＴｈｅｃＤＮＡ ( ｐｄｎ1 )ｉｓｃｏ     

大鼠脑神经元特异性烯醇化酶基因的cDNA克隆及序列分析

用ＲＴ－ＰＣＲ方法快速克隆了Ｗｉｓｔａｒ大鼠脑神经元特异性烯醇化酶（ＮＳＥ）的ｃＤＮＡ,将此包括编码全长ＮＳＥ４３３个氨基醚的ＤＮＡ片段重组入ｐＵＣ质粒,并用ＰＣＲ方法测定了全部顺序,经重复实验,发现Ｗｉｓｔａｒ大鼠与Ｆｏｒｓｓ－Ｐｅｔｔｅｒ报导的ＳＤ大鼠ＮＳＥ基因顺序,有两外单碱基的差别,其中一个涉及氨基酸的改变。同时还对ＲＮＡ的提取及长片段ＤＮＡ的ＲＴ－ＰＣＲ扩增进行了方法学的探讨。     

人干细胞因子cDNA的设计、合成与克隆

选择大肠杆菌的偏爱密码子,分成18个长约60个碱基且相互配对的寡核苷酸片段,合成了可溶形式的人干细胞因子（hSCF)的cDNA,合成片段经纯化、5′-端磷酸化后,通过PCR进行合成hSCF的cDNA一次性组装与扩增,得到了含有可溶形式的hSCF的全部编码区及EcoRⅠ、SalⅠ位点在内的全长共515个碱基对的DNA片段,回收该DNA片段,酶切消化,定向克隆进质粒pUC19。经酶切鉴定以及序列测定,得到了全序列正确的克隆株,为下一步的工作奠定了基础。     

The rabbit muscle phosphofructokinase gene: cDNA cloning and sequencing

A partial cDNA for rabbit muscle phosphofructokinase (Rm-PFK) has been cloned and sequenced. The nucleotide sequence of the cDNA agrees with the previously determined Rm-PFK genomic sequence. In addition, the amino acid sequence deduced from the cDNA is nearly identical to the Rm-PFK sequence previously determined by peptide analysis. A significant degree of homology exists when the amino acid sequence of Rm-PFK is compared with the sequences of Bacillus stearothermophilus PFK or Escherichia coli PFK-1. The cloning and sequencing of the PFK cDNA fragment represents significant progress toward the long term goal of using site-specific mutagenesis to investigate the structure-function relationships in this allosteric enzyme.     

cDNA cloning of the neutrophil bactericidal peptide indolicidin.

A structurally novel, tryptophan-rich antimicrobial tridecapeptide amide, named indolicidin, has recently been purified from bovine neutrophils (Selsted et al. (1992) J. Biol. Chem. 267, 4292-4295). Here we describe the molecular cloning of this endoantibiotic, which is synthesised in bone marrow cells as a 144 amino acid residue precursor. The encoded protein has a predicted mass of 16479 Da and a pI of 6.51. A putative signal peptide of 29 amino acids precedes a 101 residue pro-region. The mature peptide is at the 3' end of the open reading frame. A glycine, not found in purified indolicidin, is present at the carboxyl terminus of the deduced sequence and is very likely involved in post-translational peptide amidation.     

Isolation and cDNA cloning of a novel galanin-like peptide (GALP) from porcine hypothalamus

Galanin is a widely distributed neuropeptide with a variety of physiological functions. Three galanin receptor subtypes, GALR1, GALR2, and GALR3, have been reported. We isolated a novel galanin-like peptide (GALP) from porcine hypothalamus by observing its activity for increasing [(35)S]GTPgammaS binding to a membrane preparation of GALR2-transfected cells. The peptide had 60 amino acid residues and a non-amidated C terminus. The amino acid sequence of GALP-(9-21) was completely identical to that of galanin-(1-13). A cloned porcine GALP cDNA indicated that GALP was processed from a 120-amino acid GALP precursor protein. The structures of rat and human GALP-(1-60) were deduced from cloned cDNA, which indicated that the amino acid sequences 1-24 and 41-53 were highly conserved between humans, rats, and pigs. Receptor binding studies revealed that porcine GALP-(1-60) had a high affinity for the GALR2 receptor (IC(50) = 0.24 nM) and a lower affinity for the GALR1 receptor (IC(50) = 4.3 nM). In contrast, galanin showed high affinity for the GALR1 (IC(50) = 0.097 nM) and GALR2 receptors (IC(50) = 0.48 nM). GALP is therefore an endogenous ligand that preferentially binds the GALR2 receptor, whereas galanin is relatively non-selective.     

cDNA cloning of halocidin and a new antimicrobial peptide derived from the N-terminus of Ci-META4

Halocidin is an antimicrobial peptide, which is isolated from hemocytes from the tunicate, Halocynthia aurantium. In this study, we cloned the full-length cDNA of halocidin from pharyngeal tissue, using a combination of RT-PCR and 5′-RACE-PCR. The observed cDNA structure indicated that halocidin is synthesized as a 10.37 kDa prepropeptide. Based on the cDNA structure and the known amino acid sequence of the mature peptide, it was concluded that the precursor of halocidin contains a 21-residue signal peptide, followed by the 18 residues of the mature peptide, and a 56-residue anionic C-terminal extension, which is removed later on in the process. The signal sequence of halocidin exhibited a high degree of similarity with the corresponding portion of the Ci-META4 protein, which had been previously discovered in the coelomic cells of another tunicate, Ciona intestinalis, and is considered to play a role in metamorphosis. However, in several respects, the cDNA structure of Ci-META4 suggested that it might constitute a precursor for an antimicrobial peptide. Thus, we prepared a synthetic peptide, which was comprised of 19 N-terminal amino acid residues in the predicted mature region of Ci-META4, and tested it with regard to its antimicrobial activity. As a result, we confirmed that the synthetic peptide exhibited potent antimicrobial activity against Gram (+) and (−) bacteria, while evidencing no hemolytic activity toward human erythrocytes.     

Neutrophil attractant/activation protein-1 and monocyte chemoattractant protein-1 in rabbit. cDNA cloning and their expression in spleen cells

Rabbit neutrophil attractant/activation protein-1 (NAP-1) and monocyte chemoattractant protein-1 (MCP-1) were investigated. Rabbit spleen cells stimulated with 5 micrograms/ml of Con A produced both neutrophil and monocyte chemotactic activity. Physicochemical characteristics of those activities obtained by HPLC gel filtration and HPLC chromatofocusing were very similar to those of human NAP-1 and MCP-1, suggesting that rabbit spleen cells produce NAP-1 and MCP-1 after Con A stimulation. A cDNA library was constructed from mRNA purified from Con A-stimulated rabbit spleen cells and screened with oligonucleotide probes. By two rounds of screening, NAP-1 and MCP-1 cDNA were cloned. NAP-1 cDNA comprises 1500 bp with an open reading frame that encodes for a 101-amino acid protein highly similar to human NAP-1. MCP-1 cDNA comprises 607 bp with an open reading frame that encodes for a 124-amino acid protein highly similar to human MCP-1. Expression of NAP-1 and MCP-1 mRNA by rabbit spleen cells was studied. Both Con A- and LPS-stimulated spleen cells expressed NAP-1 and MCP-1 mRNA, but the kinetics of expression were different. Con A rapidly induced high NAP-1 and MCP-1 mRNA expression. LPS also rapidly induced NAP-1 mRNA expression, but high MCP-1 mRNA expression was not observed until 15 h after stimulation. Immunoprecipitation of metabolically labeled NAP-1 and MCP-1 with anti-human NAP-1 or MCP-1 polyclonal antibodies was attempted. Immunoprecipitated rabbit NAP-1 with a molecular mass of about 7 kDa was detected by SDS-PAGE and radioautography, but MCP-1 was not. Cloned rabbit NAP-1 and MCP-1 will give us opportunities to study the role of NAP-1 and MCP-1 in vivo.     

Purification and cDNA cloning of a cecropin-like peptide from the great wax moth, Galleria mellonella

A cecropin-like antimicrobial peptide, Gm cecropin, was purified from hemolymph of larvae of the wax moth, Galleria mellonella, immunized against E. coli, and its antibacterial activity was examined in a radial diffusion assay. The molecular mass of Gm cecropin was 4,160.69 Da by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry analysis. The full-length cDNA of the Gm cecropin precursor was cloned by a combination of RT-PCR, based on the N-terminal sequence obtained by Edman degradation, and 5'-RACE-PCR. Analysis of the cDNA showed that cecropin is synthesized as a prepropeptide, with a putative 22-residue signal peptide, a 4-residue propeptide and a 39-residue mature peptide with a calculated mass of 4,344.18 Da the difference between the calculated and measured masses suggests that Gm cecropin is a 37-residue peptide generated by removal of the C-terminal residue and amidation.