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61.
Transforminggrowthfactor-β1(TGF-β1)is amultifunctionalpolypeptidethatregulatesanum-berofcellularprocesses,includingcellprolifera-tion,differentiation,apoptosis,migration,matrix synthesis,andtheimmuneresponse[1,2].Inchron-icrenaldiseases,TGF-β1isakeymediatorofex-tracellularmatrix(ECM)accumulation[3].Oneof thetargetrenalcellsforTGF-β1isglomerular mesangialcellsthatarecapableofproducingcom-ponentsofECM,suchascollagens,lamininand fibronectin[4,5].Recentstudiesindicatedthatinhi-bitionofT… 相似文献
62.
目的构建大鼠维生素D受体(VDR)蛋白表达载体,测定并分析遗传性高钙尿性结石(GHS)大鼠VDRcDNA序列。方法采用半定量逆转录-聚合酶链反应(RT—PCR)方法扩增含VDR蛋白编码基因序列,将扩增产物克隆至真核表达载体pcDNA3.1/Zero(+),对5只GHS大鼠和4只正常尿钙对照(NC)大鼠十二指肠VDRcDNA序列进行测序分析。结果琼脂糖凝胶电泳示PCR扩增产物碱基数目与目的片段大小一致。对重组质粒的分析表明,插入片段的序列与发表的VDR基因编码序列相同。5只GHS鼠和4只NC鼠肠VDR cDNA序列均有3个相同的位点不同于已公布的大鼠肠VDR cDNA序列:在256bp位点:C取代G;569bp位点:G代替A;1658位点:A替代G。另外,GHS鼠在1795bp位点发生改变,G取代A,而NC鼠则无改变。结论大鼠维生素D受体蛋白编码序列被成功地克隆至表达载pcDNA3.1/Zero(+)上。GHS大鼠基因编码区的序列组成同NC大鼠相一致,但GHS鼠1795bp位点的碱基改变未见于NC鼠。 相似文献
63.
β—内啡肽增强人外周血单个核细胞IL—2和IFN—γmRNA的表达 总被引:2,自引:0,他引:2
应用逆转录-多聚酶链反应及Sonthern杂交技术,研究卜内啡肽(β-END)对PHA诱导的人外周血单个核细胞IL-2和IFN-ΥmRNA表达的调节作用。结果发现β-END(10-8~10-14mol/L)可显著增强IL-2和IFN-ΥmRNA的表达并呈剂量依赖性关系,此外发现β-END对IL-2mRNA的增强作用可被阿片肽受体桔抗剂——纳络酮逆转。本研究从基因水平上证明了神经递质可通过影响免疫细胞细胞因子调节免疫功能。 相似文献
64.
The neurotransmitter biosynthetic enzymes, tyrosine hydroxylase (TH), and tryptophan hydroxylase (TPH) are each composed of
an amino-terminal regulatory domain and a carboxylterminal catalytic domain. A chimeric hydroxylase was generated by coupling
the regulatory domain of TH (TH-R) to the catalytic domain of TPH (TPH-C) and expressing the recombinant enzyme in bacteria.
The chimeric junction was created at proline 165 in TH and proline 106 in TPH because this residue is within a conserved five
amino-acid span (ValProTrpPhePro) that defines the beginning of the highly homologous catalytic domains of TH and TPH. Radioenzymatic
activity assays demonstrated that the TH-R/TPH-C chimera hydroxylates tryptophan, but not tyrosine. Therefore, the regulatory
domain does not confer substrate specificity. Although the TH-R/TPH-C enzyme did serve as a substrate for protein kinase (PKA),
activation was not observed following phosphorylation. Phosphorylation studies in combination with kinetic data provided evidence
that TH-R does not exert a dominant influence on TPH-C. Stability assays revealed that, whereas TH exhibited a t1/2 of 84 min at 37°C, TPH was much less stable (t
1/2=28.3 min). The stability profile of TH-R/TPH-C, however, was superimposable on that of TH. Removal of the regulatory domain
(a deletion of 165 amino acids from the N-terminus) of TH rendered the catalytic domain highly unstable, as demonstrated by
at
1/2 of 14 min. The authors conclude that the regulatory domain of TH functions as a stabilizer of enzyme activity. As a corollary,
the well-characterized instability of TPH may be attributed to the inability of its regulatory domain to stabilize the catalytic
domain. 相似文献
65.
66.
M. Jung E. Krämer M. Grzenkowski K. Tang W. Blakemore A. Aguzzi K. Khazaie K. Chlichlia G. von Blankenfeld H. Kettenmann J. Trotter 《The European journal of neuroscience》1995,7(6):1245-1265
Replication-defective retroviruses expressing the t- neu oncogene, or a hybrid protein with the neu tyrosine kinase linked to the external region of the human epidermal growth factor receptor ( egfr-neu ), were used to establish lines of murine oligodendroglial precursor cells. Differentiation of the t- neu lines into myelin-associated glycoprotein (MAG)-positive oligodendrocytes was induced by dibutyryl cAMP, and the egfr-neu line showed limited differentiation in vitro upon withdrawal of epidermal growth factor. Cerebellar granule cell neurons expressed mitogens for the cell lines. Upon transplantation into demyelinated lesions, t- neu line cells engaged with the demyelinated axons whereas the egfr-neu line cells differentiated further and ensheathed the axons. These cell lines thus interact with neurons in vitro and in vivo and can be used as tools to define the molecules involved in different stages of neuron-glia interaction. 相似文献
67.
雌、孕激素对IL-6基因在子宫内膜表达的影响 总被引:4,自引:1,他引:3
为了进一步了解白介素-6(IL-6)在生殖过程中的作用,应用斑点杂交和原位杂交方法,研究IL-6在小鼠子宫内膜的基因表达和雌、孕激素对这种表达的影响。实验证明,正常动情前期子宫内膜间质细胞有IL-6cRNA基因表达,切除动物卵巢,即可消除这种表达。如给去卵巢动物2mg孕激素加10ng雌激素或20mg孕激素加100ng雌激素,它们的光密度(IOD)值分别可达到2.3和2.5。结果证明,子宫内膜间质细胞是产生细胞因子IL-6的主要细胞之一,并受卵巢激素的调控。 相似文献
68.
经逆转录病毒载体将人GM-CSF基因导入人膀胱癌细胞株BIU-87细胞中,建立了转基因细胞株BIU/GM。经流式细胞仪行细胞DNA周期分析表明GM-CSF基因的导人及表达对BIU-87细胞的增长无影响。免疫荧光测定发现转GM-CSF基因及表达不能促进BIU-87细胞表面HLA-ABC、DR、DQ抗原的表达。转基因瘤细胞株经6000rad X射线照射灭活后,丧失增殖能力,逐步死亡,但能维持一定水平的GM-CSF分泌活性达两周以上。从而为制备灭活的转基因瘤苗提供了初步经验。 相似文献
69.
70.
Septic or inflammatory stimuli suppress drug metabolism by cytochrome P-450 in the liver, presumably at the pretranslational level. We have shown previously that nitric oxide is responsible at least in part for the inhibition by bacterial lipopolysaccharide of phenobarbital-induced CYP2B1/2 activity in vivo. This was attributed to the interaction of nitric oxide with heme in the active-center of cytochrome P450, leading to enzyme inactivation. Here, we report of nitric oxide with heme in the active-center of cytochrome P450, leading to enzyme inactivation. Here, we report that endogeneous nitric oxide also contributes to LPS-induced suppression of CYP2B1/2 in vivo by down-regulating the expression of CYP2B1/2 protein and mRNA. 相似文献