Impaired control of IRES-mediated translation in X-linked dyskeratosis congenita

The DKC1 gene encodes a pseudouridine synthase that modifies ribosomal RNA (rRNA). DKC1 is mutated in people with X-linked dyskeratosis congenita (X-DC), a disease characterized by bone marrow failure, skin abnormalities, and increased susceptibility to cancer. How alterations in ribosome modification might lead to cancer and other features of the disease remains unknown. Using an unbiased proteomics strategy, we discovered a specific defect in IRES (internal ribosome entry site)-dependent translation in Dkc1(m) mice and in cells from X-DC patients. This defect results in impaired translation of messenger RNAs containing IRES elements, including those encoding the tumor suppressor p27(Kip1) and the antiapoptotic factors Bcl-xL and XIAP (X-linked Inhibitor of Apoptosis Protein). Moreover, Dkc1(m) ribosomes were unable to direct translation from IRES elements present in viral messenger RNAs. These findings reveal a potential mechanism by which defective ribosome activity leads to disease and cancer.     

Inhibition of experimental liver cirrhosis in mice by telomerase gene delivery

Accelerated telomere loss has been proposed to be a factor leading to end-stage organ failure in chronic diseases of high cellular turnover such as liver cirrhosis. To test this hypothesis directly, telomerase-deficient mice, null for the essential telomerase RNA (mTR) gene, were subjected to genetic, surgical, and chemical ablation of the liver. Telomere dysfunction was associated with defects in liver regeneration and accelerated the development of liver cirrhosis in response to chronic liver injury. Adenoviral delivery of mTR into the livers of mTR(-/-) mice with short dysfunctional telomeres restored telomerase activity and telomere function, alleviated cirrhotic pathology, and improved liver function. These studies indicate that telomere dysfunction contributes to chronic diseases of continual cellular loss-replacement and encourage the evaluation of "telomerase therapy" for such diseases.     

An essential signaling role for the m3G cap in the transport of U1 snRNP to the nucleus

The major small nuclear ribonucleoprotein particles (snRNPs) U1, U2, U4 + U6, and U5 have to be transported from the cytoplasm, where they are synthesized, to the nucleus, where they splice pre-messenger RNAs. Since the free core snRNP proteins in the cytoplasm do not enter the nucleus on their own, the nuclear location signal must either reside on the snRNA or be created as a result of snRNA-protein interaction. Here the involvement by the 5'-terminal cap of snRNA molecules in the nucleo-cytoplasmic transport of UsnRNPs has been studied by microinjection of synthetic U1 RNA molecules into frog oocytes; the U1 RNA bore either the normal cap (m3G) or a chemical derivative. Antibodies in the cytoplasm against the m3G cap inhibited the nuclear uptake of U1 snRNP. U1 RNA that was uncapped or contained an unnatural ApppG cap did not enter the nucleus, even though it carried a normal complement of protein molecules. When the ribose ring of the m3G cap was oxidized with periodate, nuclear transport of U1 snRNPs was severely inhibited. Finally, microinjection of m3G cap alone (but not m7G cap) into oocytes severely inhibited the transport of U1 snRNPs to the nucleus. These data suggest that one step in the nuclear uptake of U1 snRNPs involves the m3G cap structure.     

mtDNA A3243G 点突变小鼠模型的建立及其致病机制探讨

    利用显微注射线粒体技术建立转人线粒体小鼠模型,研究外源突变mtDNA在不同组织的分布及遗传规律,探讨mtDNA A3243G点突变对线粒体功能的影响.从健康成人及2型糖尿病患者(携带mtDNA 3243A-G突变)血液标本中分离有活性的线粒体,将其显微注射至小鼠受精卵,胚胎移植,产出仔鼠后利用分子生物学方法检测人mtDNA及mtDNA A3243G点突变.获得嵌合体小鼠后,对其空腹血糖和全血乳酸进行测定,并使用荧光法和比色法分析A3243G点突变小鼠重要脏器组织细胞活性氧生成量(ROS)、线粒体复合酶Ⅰ和Ⅳ活力及线粒体ATP合成活力的变化.研究结果显示:在1只雌性(转健康人线粒体)和2只雄性小鼠(转患者线粒体)中检测到人mtDNA,其中2只雄性小鼠携带mtDNA 3243A-G突变;将嵌和体雌鼠与野生型C57BL/6J 雄鼠交配后,在1只后代仔鼠中检测到人mtDNA;人mtDNA仅在嵌合小鼠的部分组织中表达.在含有mtDNA A3243G突变的组织中发现,线粒体复合酶Ⅰ、Ⅳ活力降低,ATP合成速率下降,ROS水平升高,说明A3243G点突变能损伤线粒体正常功能从而导致疾病的发生.综上所述,本研究利用显微注射法成功建立了嵌和小鼠,引入了致病性的点突变,为线粒体疾病的研究提供了良好的思路.     

Species-specific recognition of single-stranded RNA via toll-like receptor 7 and 8

Double-stranded ribonucleic acid (dsRNA) serves as a danger signal associated with viral infection and leads to stimulation of innate immune cells. In contrast, the immunostimulatory potential of single-stranded RNA (ssRNA) is poorly understood and innate immune receptors for ssRNA are unknown. We report that guanosine (G)- and uridine (U)-rich ssRNA oligonucleotides derived from human immunodeficiency virus-1 (HIV-1) stimulate dendritic cells (DC) and macrophages to secrete interferon-alpha and proinflammatory, as well as regulatory, cytokines. By using Toll-like receptor (TLR)-deficient mice and genetic complementation, we show that murine TLR7 and human TLR8 mediate species-specific recognition of GU-rich ssRNA. These data suggest that ssRNA represents a physiological ligand for TLR7 and TLR8.     

小麦杂交育种早期世代间的配合力相关性研究

为模拟现代小麦育种亲本选配和早代选择实际,选用8个产量差异较大的亲本,进行不完全双列杂交,使各种不同产量水平的品种在亲本组配中相遇,研究了产量、株高、成熟期等性状的亲本本身表现与其一般配合力间及配合力在F_1至F_3世代间的相关性。结果表明,双亲的产量及相关性值对后代有良好的预见性。根据亲本产量及综合农艺性状选择亲本是比较可靠的,从而省去一些中间环节,加速育种进程,节省人力、物力。早期世代(F_1—F_3)间配合力相关分析结果表明,一般配合力在组合早代评价上有重要意义。     

转GFP基因蚕和neor蚕的继代分析

利用PCR技术对该室采用精子介导法构建的转绿色荧光蛋白基因（GFP）蚕及基因枪法构建的新霉素抗性基因（neo^r)要进行了继代分析检测,结果在转GFP蚕的G2和G3代,转neo^r蚕的G1及G2代,均检测到了阳性个体。这说明所构建的转基因蚕具有相对稳定的遗传性。     

烟草与龙葵细胞杂交和新品系694-L选育的研究

 在烟草生产上尚存在容易感病、品质需要改进等问题。试验选用烟草（革新1号）和药用植物龙葵（野生种）为细胞杂交亲本，它们是茄科不同属的植物，有性杂交不育。用二个亲本的叶肉原生质体经诱导融合、培养、选择和鉴定得到了细胞杂种（TS-28，TS-33）。将其后代在选种圃经二年培育选出了大叶型株系694-L。再将694-L株系在鉴定圃与烟草亲本革新1号及目前黄淮海烟区统一应用的标准品种G140进行二年比较鉴定。结果表明694-L对烟草花叶病和气候斑点病的抗性均比革新1号和G140有所改善。694-L的产量和评吸结果和G140相近，但有些品质还需改进。试验将细胞杂交和有性杂交选育相结合，得到了可供进一步选育的烟草新品系，为应用细胞工程改良作物提供新的例证。     

基于微生物16SrRNA测序技术对ICR小鼠传代后肠道菌群变化的分析

为探讨不同代次雄性ICR小鼠生长发育与其肠道微生物的关系,本研究通过对16SrRNA基因V3~V4区测序,分析F0到F3代雄性ICR小鼠肠道菌群多样性和菌种组成。结果显示:1)从F0到F3代,组间微生物的Alpha多样性中的Chao1指数,Observed-species指数和香侬指数(Shannon)指数随代次积累显著降低(P<0.05),Simpson指数无显著差异(P>0.05)。2)从F0到F3代的优势菌门均为厚壁菌门(Firmicutes)(F0、F1、F2和F3丰度分别为83.3%、79.0%、81.8%和90.3%)和拟杆菌门(Bacteroides)(F0、F1、F2和F3丰度分别为6.0%、5.1%、4.0%和3.2%)。3)F0,F1和F2代三组的优势菌属均为乳酸菌属(Lactobacillus)(F0、F1和F2丰度分别为83.1%、62.8%和38.2%),但F3代的一些未确认分类的菌属占比较高,丰度约为45.3%;从F0到F3代在属水平上微生物组成上存在显著差异(P<0.05),各组的乳酸菌属丰度随代次的积累显著降低(P<0.05)。4)对差异菌属进行了KEGG差异代谢通路预测,发现乙醛酸盐代谢、胰岛素信号通路、苯丙氨酸,色氨酸和酪氨酸生物合成途径,萜类化合物生物合成途径,肽聚糖生物合成和糖酵解糖异生作用在F3代中显著降低,表明F3代氨基酸合成、糖类代谢等多条基础代谢通路受损。综上,本研究基于微生物16SrRNA测序技术对ICR小鼠传代后肠道菌群变化进行了一系列分析和功能预测,发现微生物多样性发生改变,F0至F2代优势菌门未发生明显变化,但在F3代出现了较多的为确认分类菌属,并且在属水平上各组的乳酸菌属丰度随代次的积累显著降低,F3代氨基酸合成、糖类代谢等多条基础代谢通路受到影响。本研究有助于从肠道微生物与宿主间的相互作用角度解释ICR雄性小鼠传代后出现的体重偏低等现象产生的原因。     

A novel Arabidopsis miRNA,ath-miR38-3P,is involved in response to Sclerotinia sclerotiorum infection

Plant defense responses against penetration or colonization of pathogens are mediated by activation and repression of a large array of genes. Host endogenous small RNAs are essential in gene expression reprogramming process. We identified a new Arabidopsis micro RNA(mi RNA) ath-mi R38-3P by high-throughput sequencing and further confirmed it by Northern blot assay. Interestingly, ath-miR38-3P was highly induced after infection of the pathogen Sclerotinia sclerotiorum. Further analysis based on the mi RNA target database demonstrated that ath-mi R38-3P might target to five putative genes: AT2G03140, AT5G59430, AT5G66320, AT1G36620 and AT3G03820. To confirm the target, we conducted the quantitative real-time PCR to observe the expression pattern of each candidate gene. The results showed that only AT3G03820 was down-regulated after inoculation of S. sclerotiorum. In addition, overexpression of ath-miR38-3P down-regulates AT3G03820, suggesting AT3G03820 might represent the target for ath-mi R38-3P. Our results may provide the useful information for further studying the biological function of a novel ath-mi R38-3P and its targets in Arabidopsis-Sclerotinia interaction.     

番茄糖转运蛋白SlSTP2在防御细菌性叶斑病中的功能

【背景】近年来,我国番茄生产中面临的不良气候环境导致露地和设施栽培中番茄病害日益严重。由丁香假单胞菌番茄致病变种（Pseudomonas syringae pv. tomato,Pst）所引发的番茄细菌性叶斑病频发,严重影响了番茄的产量、品质。糖是植物体内重要的信号分子与营养物质,在植物遭受病原菌侵染时,糖既可以作为信号参与调控植物抗病性,也可以作为主要碳源为免疫反应提供能量。STP（sugar transport protein）家族是一类糖转运蛋白家族,在植物生长发育过程与病原防御中起着重要作用。【目的】明确番茄中STP家族是否参与调控植株对细菌性叶斑病的抗性。【方法】以番茄CR品种（Solanum lycopersicum cv. Condine Red）为材料,通过接种Pst DC3000,明确STP基因家族对Pst DC3000的响应。构建SlSTP2的突变材料与过表达材料,并进行鉴定、繁种。在野生型和SlSTP2基因突变体、过表达植株上接种Pst DC3000,观察比较叶片发病情况、台盼蓝染色显示的死细胞数量,检测叶片菌落数（colony-forming units,CFU）和光系统II实际光化学效率,明确SlSTP2在植株防御细菌性叶斑病中的作用。为探究SlSTP2防御Pst DC3000的内在分子机制,通过双分子荧光互补（bimolecular fluorescent complimentary,BiFC）试验筛选互作蛋白,构建编码该蛋白的基因突变与过表达材料,并接种Pst DC3000明确其在植株防御细菌性叶斑病中的作用。【结果】在番茄植株上接种Pst DC3000后,SlSTP1和SlSTP2表达上调,选取上调最显著的SlSTP2作为后续研究对象,构建其突变材料与过表达材料。在番茄野生型和Slstp2突变植株、OE:SlSTP2过表达植株上接种Pst DC3000,相比野生型植株,Slstp2植株细菌性叶斑病的发病情况更严重,叶片CFU与台盼蓝染色显示出的死细胞数均更多,光系统II实际光化学效率下降,OE:SlSTP2植株则相反。通过BiFC试验发现,SlSTP2与G蛋白β亚基SlAGB1互作。接种Pst DC3000后,Slagb1突变体发病较野生型重,呈现与Slstp2突变体一致的发病表型;OE:SlAGB1则与OE:SlSTP2植株同样表现出更强的抗性。【结论】SlSTP2受Pst DC3000诱导,并正调控番茄对细菌性叶斑病的抗性,且SlSTP2与正调控因子SlAGB1互作,推测SlSTP2调控番茄细菌性叶斑病抗性与SlAGB1有关。     

Template boundary in a yeast telomerase specified by RNA structure

The telomerase ribonucleoprotein has a phylogenetically divergent RNA subunit, which contains a short template for telomeric DNA synthesis. To understand how telomerase RNA participates in mechanistic aspects of telomere synthesis, we studied a conserved secondary structure adjacent to the template. Disruption of this structure caused DNA synthesis to proceed beyond the normal template boundary, resulting in altered telomere sequences, telomere shortening, and cellular growth defects. Compensatory mutations restored normal telomerase function. Thus, the RNA structure, rather than its sequence, specifies the template boundary. This study reveals a specific function for an RNA structure in the enzymatic action of telomerase.     

抗除草剂油菜雄性不育系选育及利用研究

对抗草甘膦油菜“Quest”的抗性遗传研究结果表明,油菜对草甘膦的抗性为显性性状,由1对基因控制,抗草甘麟基因在F2和BC1群体遵循孟德尔分离规律。以抗草甘膦油菜“Quest”和双低雄性不育系“G851A”、保持系“G851B”为亲本材料,经5个轮回世代的回交、自交和测交,育成了抗除草剂油菜雄性不育系“K851A”和保持系“K851B”。“K851A”不育系株型紧凑,不育性彻底,双低品质稳定,且具有除草剂抗性,组配的杂交组合K851A/C-1平均产量达3426.0 kg/hm2,较对照增产12.84%。     

播种密度对红花酢浆草生长和功能性状的影响

本文研究了不同播种密度对红花酢浆草生长和功能性状的影响。结果表明,红花酢浆草的生长和叶片功能性状均存在负密度制约现象,当播种密度达到150粒/m²及以上时,负密度制约较强烈。本研究为酢浆草的防治和合理种植提供了一定的理论支持。     

5G水稻的演变和发展

近百年来,随着现代稻作农业的发展,水稻Oryza sativa L.品种不断地更新换代。根据水稻品种的遗传基础、特征特性及演变规律,本文把水稻品种分为5个世代（G）。第1代（1G）为高秆水稻,第2代（2G）为半矮秆水稻,第3代（3G）为亚种内杂交水稻,第4代（4G）为亚种间渗入水稻,第5代（5G）为亚种间杂交水稻。在5代水稻中,1G高秆水稻在20世纪60年代后被半矮秆水稻替代,之后基本没有大面积种植。2G半矮秆水稻、3G亚种内杂交水稻和4G亚种间渗入水稻从推广应用至今仍然在使用。5G亚种间杂交水稻即将面世。每一代水稻的出现,都是水稻品种的一次重大创新,都带来水稻育种和生产的变革。认识水稻世代的演变规律,对于把握水稻的发展方向具有重要意义。     

外源RNA导入普通小麦的初步研究

采用浸滴法将外源RNA导入普通小麦中国春，并对其D1、D2代进行分析，结果表明，变异株系在株高、穗长、穗粒数、抗倒性等性状上产生了明显的变异，变异率为31．67％；对导入RNA的中国春D1、D2代进行细胞学观察，出现了单价体、染色体落后、染色体桥、微核和细胞多极分裂等异常现象，变异率D1代为27．43％，D2代为24．05％。     

宽皮柑桔两个分类群的核型及C带带型分析

利用去壁低渗法和 BSG 法首次研究了宽皮柑桔两个分类群的核型及 Giemsa C 带带型。结果表明,道县野桔和朱桔均为18染色体数和2A 核型,且以末端带为主。核型公式分别为2n=18=14m(2SA7)+4sm 和2n=18=12m+(1SAT)+6sm(1SAT)。还从随体染色体和异染色质含量的变异探讨了宽皮柑桔的基本种模式。     

大肠杆菌质粒复制子在巴氏杆菌中传代的稳定性研究

首先将多杀性巴氏杆菌谷氨酸脱氢酶的基因gdhA启动子及鸡传染性法氏囊病病毒VP2基因插入pMD18-T质粒载体的多克隆位点中构建巴氏杆菌表达质粒pMD18T-PGDH-VP2,用该质粒转化禽多杀性巴氏杆菌G190E40株。为了解重组质粒在巴氏杆菌中传代的稳定性以判断其作为重组活疫苗的可能性,将转化菌种在含氨苄青霉素及血清的平板固体培养基上连续传代至第9代,肉眼观察下的菌落形态和显微镜下见到菌体形态与原始菌种无明显差异;每隔3代提取质粒DNA用限制性内切酶切割检查,酶切图谱没有改变;用扩增PGDH的引物,将提取3、6、9代质粒进行PCR检查,均可见约300bp的PGDH基因片段。结果表明,pMD18-T中的大肠杆菌复制子能在巴氏杆菌中稳定传递至少9代,这为构建能在禽巴氏杆菌和大肠杆菌中复制和表达外源基因的穿梭表达质粒打下了基础。     

Requirement of inositol pyrophosphates for full exocytotic capacity in pancreatic beta cells

Inositol pyrophosphates are recognized components of cellular processes that regulate vesicle trafficking, telomere length, and apoptosis. We observed that pancreatic beta cells maintain high basal concentrations of the pyrophosphate diphosphoinositol pentakisphosphate (InsP7 or IP7). Inositol hexakisphosphate kinases (IP6Ks) that can generate IP7 were overexpressed. This overexpression stimulated exocytosis of insulin-containing granules from the readily releasable pool. Exogenously applied IP7 dose-dependently enhanced exocytosis at physiological concentrations. We determined that IP6K1 and IP6K2 were present in beta cells. RNA silencing of IP6K1, but not IP6K2, inhibited exocytosis, which suggests that IP6K1 is the critical endogenous kinase. Maintenance of high concentrations of IP7 in the pancreatic beta cell may enhance the immediate exocytotic capacity and consequently allow rapid adjustment of insulin secretion in response to increased demand.     

油菜育性基因在不同分离世代的分离特性研究

】推导出１对隐性核不育基因和３对隐性核不育基因在不同分离世代的理论分离比,然后以胞质不育系Ｌ１７Ａ和陕２Ａ、细胞核＋细胞质双重不育系ＧＣＤＡ－１的多个分离世代为材料,采用卡平方适合性测验方法验算了它们所带的育性基因对数。结果表明,Ｌ１７Ａ和陕２Ａ为１对隐性不育基因控制,双重不育系由３对隐性不育基因所控制,但胞质不育基因ｓ１与两个核不育基因ｍ１ｍ２中的一个可能存在连锁关系。