pppA2’p5’A2’p5’A保护病毒感染细胞的普遍性

pppA2’p5’A2’p5’A(简称2’-5’P_3A_3)是干扰素作用于细胞后诱导产生的物质。干扰素的作用机理很复杂,其中之一是2’-5’寡聚腺苷酸合成酶的活力增加,此酶以ATP为底物合成2’-5’P_3A_3及其同系物2’-5’P_3An。但2’-5’P_3A_3或2’-5’P_3A_n本身是否具有抗病毒作用,干扰素的抗病毒作用是否通过2’-5’P_3A_3或2’-5’P_3An而进行,这是一个很     

pppA2′p5′A2′p5′A保护病毒感染细胞的普遍性

pppA2′p5′A2′p5′A(简称2′-5′P_3A_3)是干扰素作用于细胞后诱导产生的物质。干扰素的作用机理很复杂,其中之一是2′-5′寡聚腺苷酸合成酶的活力增加,此酶以ATP为底物合成2′-5′P_3A_3及其同系物2′-5′P_3An。但2′-5′P_3A_3或2′-5′P_3A_n本身是否具有抗病毒作用,干扰素的抗病毒作用是否通过2′-5′P_3A_3或2′-5′P_3A_n而进行,这是一个很     

真核翻译起始因子5A2(eIF5A2)表达载体的构建与鉴定

目的:构建真核翻译起始因子5A2(eIF5A2)真核表达载体。方法:PCR扩增eIF5A2片段,通过酶切连接将目的片段定向克隆至真核表达载体pIRES2-eGFP的多克隆位点,菌落PCR、质粒PCR及DNA测序对质粒进行鉴定。结果:菌落PCR、质粒PCR及DNA测序鉴定结果均表明载体构建正确。结论:成功构建了真核表达载体,并且命名为pIRES2-5A2,为下一步eIF5A2基因在人类肿瘤中作用的研究奠定了基础。     

干扰素作用机理和2-5A系统

诱导基因表达是干扰素发挥生物效应的主要方式。干扰素诱导基因表达可有多种途径,被诱导基因的5′端序列与诱导过程有关。干扰素诱导的2-5A合成酶合成的2-5A有多种生物活性,能模仿干扰素的许多功能,2-5A可能是高等动物细胞内的一种生长分化调节因子。     

2′5′-Phosphodiesterase Activity Studies with Xyloadenosine Analogs of 2–5A Cores

Abstract

Sequential substitution of xyloadenosine into the trimeric and tetrameric 2–5A cores¹ allows evaluation of the importance of the 3′ hydroxyl groups to 2′5′-phosphodiesterase (PDE) activity.     

翻译起始因子5A2与肿瘤的研究进展

真核翻译起始因子5A2(eukaryotic translation initiation factor 5A2,e IF5A2)是一种在真核细胞蛋白质翻译起始和延伸过程中发挥作用的蛋白,它是e IF5A的其中一个亚型,在多种肿瘤细胞中的异常高表达往往与该肿瘤的发生和发展相关。e IF5A2所特有的羟腐赖氨酸,可以成为肿瘤治疗的潜在靶点,为临床带来新的思路。     

5′-O-Dephosphorylated 2′,5′-oligoadenylate (2-5A) with 8-methyladenosine at the 2′-terminus activates human RNase L

Human ribonuclease L (RNase L), an interferon-induced endoribonuclease, becomes enzymatically active after binding to 2-5A. The 5′-phosphoryl group of 2-5A is reportedly necessary for the conformational change leading to RNase L activation. However, we found that 5′-O-dephosphorylated 2-5A tetramer analogs with 8-methyladenosine at the 2′-terminus were more effective as an activator of RNase L than the parent 2-5A tetramer. Introduction of 8-methyladenosine is thought to induce a dramatic shift of 2-5A in the binding site of RNase L.     

尿道下裂患儿包皮组织中SRD5A2的表达

目的:探讨5a-还原酶2(SRD5A2)在尿道下裂发生中的作用。方法:选择2005年6月至8月来湘雅二医院泌尿外科手术尿道下裂患儿共28例,另选尿道外口正常儿童20例为对照。应用RT-PCR方法对28例尿道下裂患者及20对照组的包皮组织中SRD5A2-mRNA表达进行检测,并结合计算机图像分析两组SRD5A2含量进行比较。结果:在所有实验样本中均有SRD5A2表达,在尿道下裂组和对照组包皮组织中SRD5A2-mRNA表达水平相比差异无统计学意义(P>0.05)。尿道下裂轻、中、重各组之间SRD5A2-mRNA表达水平相比差异无统计学意义(P>0.05)。结论:5a-还原酶2在尿道下裂患儿包皮组织中表达正常,可能与本组尿道下裂发生无关。     

SLC2A5基因及其在胰腺癌细胞中作用

胰腺癌是世界上恶劣的肿瘤之一,其存在早期诊断难于被发现,缺乏有效治疗手段以及预后效果较差等问题。近几年研究显示SLC2A5基因的上调、缺失与胰腺癌的发展、迁移相关。SLC2A5基因编码的果糖特异转运体Glut5参与细胞中果糖代谢的过程。果糖是日常生活中常见的糖源,过量摄入导致癌症的发生和迁移。该文总结了SLC2A5基因的来源、生物学功能以及其在胰腺癌中的代谢情况和作用机制,分析认为SLC2A5基因不仅影响胰腺癌生长迁移,而且可能成为胰腺癌治疗的潜在靶向研究。     

荷叶中的生物碱及其对5-HT 2A和5-HT 2C受体的激动作用研究CSCD

对荷叶中的生物碱进行了分离、鉴定和调脂减肥活性研究。本研究结合传统酸提碱沉法与现代高效液相色谱制备技术,从荷叶中分离、纯化到11个生物碱,分别被鉴定为N-氧基原荷叶碱(1)、原荷叶碱(2)、莲碱(3)、降氧化北美黄连次碱(4)、荜茇宁(5)、巴婆碱(6)、O-去甲基荷叶碱(7)、N-去甲基荷叶碱(8)、荷叶碱(9)、衡州乌药碱(10)和亚美罂粟碱(11),其中,化合物1、4和5为首次从荷叶中分得。测试所得化合物对5-HT_(2A)和5-HT_(2C)受体的激动作用,结果表明11个生物碱对5-HT_(2A)受体均具有一定的激动作用,进一步揭示了荷叶调脂减肥的可能药效基础和作用机理。     

New aporphinoid 5-HT2A and α1A antagonists via structural manipulations of nantenine

A series of C1, C2, C3 and N6 analogs of nantenine (2) was synthesized and evaluated in 5-HT(2A) and α(1A) receptor functional assays. Alkyl substitution of the C1 and N6 methyl groups of nantenine provided selective 5-HT(2A) and α(1A) antagonists, respectively. The C2 alkyloxy analogs studied were generally selective for α(1A) versus 5-HT(2A). The C3 bromo analog 15 is one of the most potent aporphinoid 5-HT(2A) antagonists known presently.     

A bacteriophage-induced 5-methyldeoxycytidine 5′-monophosphate kinase

Bacteriophage XP-12-infected Xanthomonas oryzae have been found to be a source of a kinase preparation which converts m⁵dCMP to m⁵dCDP and then to m⁵dCTP using ATP as the phosphate donor. Optimal formation of the triphosphate required the presence of creatine phosphate and creatine kinase. In the presence of dGTP, dTTP and dATP, Escherichia coli DNA polymerase I and T4 DNA polymerase catalyzed the incorporation of m⁵dCTP into DNA just as efficiently as that of dCTP. Neither dTMP nor dCMP served as substrate for the m⁵dCMP monophosphate kinase. Analogous preparations from uninfected X. oryzae were unable to phosphorylate m⁵dCMP.     

重庆居民5-HT2A基因多态性与原发性高血压关系

以聚合酶链PCR法分析重庆市一般人群的5-HT2A基因C102T多态性(样本总数348人,其中高血压组:HT=137例,非高血压组:NT=211例)的临床指标间的相关性与频率分布。了解重庆地区汉族人群5-羟色胺受体2基因(5-hydroxytryptamine receptor gene,5-HT2A)C102T多态性与原发性高血压病(essential hypertension,EH)的关系。卡方检验结果显示5-HT2A的C102T基因多态性(P=0.549)与等位基因频率(P=0.263)在HT与NT之间没有显著性统计学差异;5-HT2A的C102T基因多态性与高血压logistic回归模型分析结果显示也未见显著性差异,卡方值(Wald)为0.399;比值比为0.884;95%的可信区间为0.603~1.296,P值为0.528。一般线性模型分析结果:5-HT2A基因C102T多态性与收缩压,舒张压之间没有显著性统计学差异,PSBP=0.868,PDBP=709。5-HT2A的C102T多态性可能与重庆汉族人群EH无关。     

A homopolymer of the potent antitumor drug 2′-deoxy-5-fluorouridylate

Poly(5-fluoro-2′-deoxyuridylic acid) was synthesized and its properties were compared with those of poly(dT) and poly(dU). It readily complexed with poly(dA). The 1:1 complex melted at about 20°C lower than poly(dA) · poly(dT). A triple-stranded helix, poly(dA)·2 poly(dF⁵U) was formed only in high salt (2.0 M NaCl).     

pppA_2′p_5′A_2′p_5′A对甲胎蛋白抑制巨噬细胞功能的对抗作用

干扰素是一类由干扰素诱生剂诱导生物机体有关细胞产生的糖蛋白,具有广泛的生物学活性,能抗病毒、抗癌肿、及免疫调节等功能。pppA_(2′)p_(5′)A_(2′)p_(5′)A(简称2′-5′P_3A_3)是由干扰素作用于细胞以后诱导产生的一种寡聚腺苷酸,它能表现干扰素的许多生物学功能,我们发现2′-5′P_3A_3能激活巨噬细胞,但激活特点与干扰素本身不同。干扰素激     

Dopamine D2 and 5-hydroxytryptamine 5-HT(₂A) receptors assemble into functionally interacting heteromers

In view of the co-distribution of dopamine D_2LR and 5-hydroxytryptamine 5-HT_2A receptors (D_2LR and 5-HT_2AR, respectively) within inter alia regions of the dorsal and ventral striatum and their role as a target of antipsychotic drugs; in this study we assessed the potential existence of D_2LR-5-HT_2AR heteromers in living cells and the functional consequences of this interaction. Thus, by means of a proximity-based bioluminescence resonance energy transfer (BRET) approach we demonstrated that the D_2LR and the 5-HT_2AR form stable and specific heteromers when expressed in HEK293T mammalian cells. Furthermore, when the D_2LR-5-HT_2AR heteromeric signaling was analyzed we found that the 5-HT_2AR-mediated phospholipase C (PLC) activation was synergistically enhanced by the concomitant activation of the D_2LR as shown in a NFAT-luciferase reporter gene assay and a specific and significant rise of the intracellular calcium levels were observed when both receptors were simultaneously activated. Conversely, when the D_2LR-mediated adenylyl cyclase (AC) inhibition was assayed we showed that costimulation of D_2LR and 5-HT_2AR within the heteromer led to inhibition of the D_2LR functioning, thus suggesting the existence of a 5-HT_2AR-mediated D_2LR trans-inhibition phenomenon. Finally, a bioinformatics study reveals that the triplet amino acid homologies LLT (Leu-Leu-Thr) and AIS (Ala-Ile-Ser) in TM1 and TM3, respectively of the D₂R-5-HT_2AR may be involved in the receptor interface. Overall, the presence of the D_2LR-5-HT_2AR heteromer in discrete brain regions is postulated based on the existence of D_2LR-5-HT_2A receptor-receptor interactions in living cells and their codistribution inter alia in striatal regions. Possible novel therapeutic strategies for treatment of schizophrenia should be explored by targeting this heteromer.