过氧化物酶体增生激活型受体γ与AS

过氧化物酶体增生激活型受体γ（PPARγ）在组织中较为广泛地表达,主要是调节脂肪细胞分化、糖稳态,为噻唑烷二酮类抗糖尿病药物的生物学受体。PPARγ表达增强或激活可调节脂质代谢,抑制单核／巨噬细胞功能,减少细胞粘附分子和其他炎症介质的产生和释放,并抑制血管平滑肌产殖和迁移;可能改善某些动脉粥样硬化（atherosclerosis,AS)的危险因素,在AS的发生发展过程中具有重要意义。     

OsFY, a Homolog of AtFY, Encodes a Protein that Can Interact with OsFCA-γ in Rice （Oryza sativa L.）

FCA and FY are flowering time related genes involved in the autonomous flowering pathwayin Arabidopsis.FCA interacts with FY to regulate the alternative processing of FCA pre-mRNA.The FCA/FY interaction is also required for the regulation of FLC expression,a major floral repressor in Arabidopsis.However,it is not clear if the regulation of this autonomous flowering pathway is also present in monocotplants,such as rice.Recently,alternative RNA processing of OsFCA was observed in rice,which stronglysuggested the existence of an autonomous flowering pathway in rice.In this work,we cloned the cDNA ofthe autonomous flowering pathway gene OsFY from rice.The predicted OsFY protein contained a conserved7 WD-repeat region and at least two Pro-Pro-Leu-Pro motifs compared to Arabidopsis FY.The protein-protein interaction between OsFY and OsFCA-γ,the key feature of their gene function,was also demon-strated using the yeast two-hybrid system.The GenBank database search provided evidence of expressionfor other autonomous pathway gene homologs in rice.These results indicate that the autonomous floweringpathway is present in monocots,and the regulation through FY and FCA interaction is conserved betweenmonocots and dicots.     

Preassembly and ligand-induced restructuring of the chains of the IFN-γ receptor complex： the roles of Jak kinases, Statl and the receptor chains

We previously demonstrated using noninvasive technologies that the interferon-gamma （IFN-γ） receptor complex is preassembled [ 1 ]. In this report we determined how the receptor complex is preassembled and how the ligand-mediated conformational changes occur. The interaction of Statl with IFN-γR1 results in a conformational change localized to IFN- γR1. Jakl but not Jak2 is required for the two chains of the IFN-γ receptor complex （IFN-γR1 and IFN-γR2） to interact; however, the presence of both Jakl and Jak2 is required to see any ligand-dependant conformational change. Two IFN- γR2 chains interact through species-specific determinants in their extracellular domains. Finally, these determinants also participate in the interaction of IFN-γR2 with IFN-γR1. These results agree with a detailed model of the IFN-γ receptor that requires the receptor chains to be pre-associated constitutively for the receptor to be active.     

PPARγ与代谢性疾病

过氧化物酶体增殖物激活受体γ(PPARγ)是一种可由多种脂肪酸及其衍生物激活的核转录因子,在机体糖脂代谢中起重要调节作用,一些可作为其配体的合成化合物现已应用于Ⅱ型糖尿病的临床治疗。该简单介绍PPARγ作用的分子机制以及PPARγ与一些代谢性疾病的关系。     

IFN-γ介导的信号转导及其在抗感染中的作用

综述干扰素-γ(IFN-γ)在信号传递及其抗微生物感染及免疫调节作用。     

Interferon-γ mRNA attenuates its own translation by activating PKR： A molecular basis for the therapeutic effect of interferon-β in multiple sclerosis

PKR, the interferon （IFN）-inducible protein kinase activated by double-stranded RNA, inhibits translation by phosphorylating the initiation factor eIF2α chain. Uniquely, human IFN-γ mRNA uses local activation of PKR in the cell to control its own translation yield. IFN-γ mRNA activates PKR through a structure in its 5＇- region harboring a pseudoknot which is critical for PKR activation. Mutations that impair pseudoknot stability reduce the ability of IFN-γ mRNA to activate PKR and strongly increase its translation efficiency. The cis-acting RNA element in IFN-γ mRNA functions as a biological sensor of intracellular PKR levels. During an immune response, as IFN-γ and other inflammatory cytokines build up in the cell＇s microenvironment, they act to induce higher levels of PKR in the cell, resulting in a more extensive activation of PKR by IFN-γ mRNA. With the resulting phosphorylation of eIF2α, a negative feedback loop is created and the production of IFN-γ is progressively attenuated. We propose that the therapeutic effect of IFN-β in multiple sclerosis may rest, at least in part, on its exquisite ability to induce high levels of PKR in the cell and thereby to limit IFN-γ mRNA translation through this negative feedback loop, blocking the excessive IFN-γ gene expression that precedes clinical attacks.     

动脉粥样硬化早期病变过程CD36的表达与oxLDL的摄取作用

清道夫受体CD36最初被认为是一种血小板膜糖蛋白和一种血栓反应蛋白受体(TSP-1)。近来,CD36也被认为是单核细胞产生的活性氮物质修饰的低密度脂蛋白(LDL)的主要受体,参与包括动脉粥样硬化(AS)在内的许多病理生理过程。该文介绍CD36的生物学特性及其在巨噬细胞源性泡沫细胞形成和AS形成中的作用,以及CD36表达的调控机制。     

鸡IFN-γcDNA的克隆及测序

应用逆转录-多聚酶链反应（RT-PCR）技术,参照图外报道的鸡γ干扰素（CHIFN-γ）cDNA全基因序列,利用自行设计合成的一对引物,从ConA诱导培养的SPF鸡外周血淋巴细胞中扩增出CHIFN-γcDNA基因,并与PMD18-T载体连接,构建了CHIFN-γ基因重组体,经DNA序列测定,确认为CHIFN-γ基因,为进一步表达CHIFN-γ奠定了基础。     

IFN-γ在沙眼衣原体感染的细胞培养中的影响

为了探讨IFN-γ在沙眼衣原体（chlamydia trachomatis,ct)感染细胞培养中的影响,本实验采用不同浓度γ-干扰素作用于ct感染的HeLa细胞,用透射电镜观察HeLa细胞内原体（elementary bodies,EBs)和网状体（reticulate bodies,RBs)。同时用反相高效液相色谱法（reversed-phase high performance liquid chromatography,HPLC)测定细胞内色氨酸的浓度。结果显示不同浓度γ-干扰素作用下细胞内ct的EBs和RBs形态及数量不同,中高浓度的IFN-γ作用下胞内EBs和RBs明显减少或轻度减少,et生长受到抑制,细胞内色氨酸含量与γ-干扰素量呈负相关,说明IFN-γ通过诱导产生2,3-吲哚-双加氧酶（indoleamine2,3-dioxygenase,IDO)降解色氨酸而抑制ct生长,提示γ-干扰素是抑制细胞内感染ct生长的一个重要因素。     

白细胞介素-18研究进展

白细胞介素 １８（ＩＬ １８）,是最近发现的一种新型免疫细胞调节因子,能显著刺激Ｔｈ１细胞产生ＩＦＮ γ,所以最初命名为ＩＧＩＦ（ＩＦＮ γｉｎｄｕｃｉｎｇｆａｃｔｏｒ）。它与ＩＬ １２有协同作用,却不互相依赖。此外,它还能增强ＮＫ细胞和ＦａｓＬ介导的细胞毒效应,能促进内毒素引发的肝损伤。在肿瘤、自身免疫性疾病及抗炎症治疗中可能有潜在的应用前景     

γ-干扰素信号通路及功能相关基因

γ-干扰素(IFN-γ)是细胞因子超家族中IFN家族的重要成员,具有抗病毒、抗肿瘤及免疫调节等多种生物学功能。IFN-γ在其效应细胞内多种信号转导途径的交互作用及其相关刺激基因的表达,导致了其生物学功能的复杂性和多样性。章对IFN-γ及其受体的结构和功能;IFN-γ介导的多条信号转导通路,以及IFN-γ刺激基因的生物学功能等作概述。     

PPARγ激动剂的四种筛选方法

总结了目前国内外PPARγ激动剂的筛选方法,重点个绍了近年来刚发展起来的基于新技术的几种高通量筛选方法。     

磷脂酶C-γ功能研究进展

磷脂酶C-γ(PLC-γ)被激活后,通过两种不同的活化机制催化水解PIP2,产生IP3和DAG。IP3和DAG分别介导钙离子从钙泵中释放以及激活蛋白激酶C,从而形成一个关键的跨膜转导信号组分。现已知道,PLC-γ在细胞周期、细胞转化、生长和发育、细胞凋亡以及调控细胞肌动蛋白骨架等生命活动过程中起着重要的调节作用。另外,PLC-γ与其他转导信号,如PKC、Ras、Ca^2 等存在cross-talk关系。     

激光—核辐射诱变小麦后代相关遗传力的分析

本试验采用Ｈｅ－Ｎｅ和Ｎ２激光辐照“汉原小麦”等四个材料的干种子,采用随机区组设计,重复三次,利用生物统计学和数量遗传学的方法,从个水平上对激光－核辐射小麦Ｌ２代抽穗期等１９个性状的相关遗传力分析表明：利用株高间接选择结实小穗数、旗叶长、小穗密度和有效分蘖数。     

磷酸脂酶C—γ的信号传递研究进展

信号分子磷脂酶C－γ（PLC－γ）被蛋白酪氨酸酶（PTK）激活催化水解磷脂酰肌醇4,5－二磷酸（PIP2）生成第二信使分子肌醇三磷酸（IP3）和二酰基甘油（DAG）,参与受体酪氨酸激酶（RTK）介导的细胞分列、抗原与免疫细胞受体结合引起免疫反应及卵细胞受精等过程中的信号传递。     

Th1细胞因子(IFN-γ)在幽门螺杆菌致病中的作用

目的：评价Thl细胞因子IFN-γ在幽门螺杆菌(Hp)感染时对胃上皮细胞的作用。方法：胃上皮细胞经IFN-γ处理后,流式细胞术测定表面MHC-Ⅱ类分子的表达和Hp的黏附,ELISA法测定细胞因子对Hp致胃上皮细胞凋亡的影响。结果：IFN-γ可诱导胃上皮细胞表达MHCR类分子,进而增加Hp的黏附。IFN-γ本身即可诱导胃上皮细胞凋亡,并可促进Hp诱导的胃上皮凋亡。结论：Thl细胞因子IFN-γ参与并加剧了Hp感染所致的胃黏膜炎症。     

中国鸭IFN—γ基因的克隆与表达

鸭乙型肝炎病毒（DHBV）感染鸭,是研究IFN－γ在机体自然感染过程中机体与病毒的相互作用和病毒的清除机制的良好动物模型。从PHA刺激后的鸭外周血单核细胞（PBMC）中提取RNA,通过RT－PCR获得鸭IFN－γ（DuIFN-γ）cDNA基因,构建DuIFN-γ真核表达质粒,转染COS－7细胞,经细胞病变效应（CPE）抑制分析和MTT法对重组DuIFN-γ滴度进行测定。实验表明,重组DuIFN-γ能够抑制VSV感染鸭胚成纤维细胞而产生的细胞病变效应。抗－DuIFN-γ抗体,能中和这种抗病毒活性。并且,GST－DuIFN-γ融合蛋白在大肠杆菌中得到表达和进一步纯化。     

LIGHT sensitizes IFNγ-mediated apoptosis of HT-29 human carcinoma cells through both death receptor and mitochondria pathways

LIGHT [homologous to lymphotoxins, shows inducible expression, and competes with herpes simplex virus glycoprotein D for herpes virus entry mediator (HVEM/TR2)] is a new member of TNF superfamily. The HT-29 colon cancer cell line is the most sensitive to LIGHT-induced, IFNγ-mediated apoptosis among the cell lines we have examined so far. Besides downregulation of Bcl-XL, upregulation of Bak, and activation of both PARP [poly (ADP-ribose) polymerase] and DFF45 (DNA fragmentation factor), LIGHT-induced, IFNy-mediated apoptosis of HT-29 cells involves extensive caspase activation. Caspase-8 and caspase-9 activation, as shown by their cleavages appeared as early as 24 h after treatment, whereas caspase-3 and caspase-7 activation, as shown by their cleavages occurred after 72h of LIGHT treatment. Caspase-3 inhibitor Z-DEVD-FMK (benzyloxycarbonyl-Asp-Glu-Val-Asp-fluoromethylketone) and a broad range caspase inhibitor Z-VAD-FMK (benzyloxycarbonyl-Val-Ala-Asp fluoromethylketone) were able to block LIGHT-induced, IFNγ-mediated apoptosis of HT-29 cells. The activity of caspase-3, which is one of the major executioner caspases, was found to be inhibited by both Z-DEVD-MFK and Z-VAD-FMK. These results suggest that LIGHT-induced, IFNy-mediated apoptosis of HT-29 cells is caspase-dependent, and LIGHT signaling is mediated through both death receptor and mitochondria pathways.