Generation of Minute phenotypes by a transformed antisense ribosomal protein gene

Antisense RNAs have been used for gene interference experiments in many cell types and organisms. However, relatively few experiments have been conducted with antisense genes integrated into the germ line. In Drosophila reduced ribosomal protein (r-protein) gene function has been hypothesized to result in a Minute phenotype. In this report we examine the effects of antisense r-protein 49 expression, a gene known to correspond to a Minute mutation An antisense rp49 gene driven by a strong and inducible promoter was transformed into the Drosophila germ line. Induction of this gene led to the development of flies with weak Minute phenotypes and to the transient arrest of oogenesis. Parameters that may affect the success of antisense gene inactivation are discussed. © 1992 Wiley-Liss, Inc.     

Generation of Minute phenotypes by a transformed antisense ribosomal protein gene.

Antisense RNAs have been used for gene interference experiments in many cell types and organisms. However, relatively few experiments have been conducted with antisense genes integrated into the germ line. In Drosophila reduced ribosomal protein (r-protein) gene function has been hypothesized to result in a Minute phenotype. In this report we examine the effects of antisense r-protein 49 expression, a gene known to correspond to a Minute mutation An antisense rp49 gene driven by a strong and inducible promoter was transformed into the Drosophila germ line. Induction of this gene led to the development of flies with weak Minute phenotypes and to the transient arrest of oogenesis. Parameters that may affect the success of antisense gene inactivation are discussed.     

芹菜NHL-like蛋白基因克隆与表达分析

植物生长发育过程中会遭遇各种病原物的攻击,植物为了应对这些危害并适应外界的生存竞争,逐渐演化出了复杂的防御机制。NHL基因家族庞大,部分NHL基因受病原物诱导后会过量表达,增强植物对多种病原菌的抗性,是与植物防御机制密切相关的蛋白。本研究以津南实芹和美国西芹2个芹菜品种为试验材料,分别克隆出NHL-like蛋白基因AgNHL。序列分析表明,上述2种芹菜的AgNHL基因序列均含636 bp的开放阅读框,编码211个氨基酸。2种芹菜碱基序列,只有第36位不同,津南实芹为T,美国西芹为C,2种碱基序列相似性高达99.84%,编码的氨基酸序列相同。进化分析显示,2种芹菜的NHL-like蛋白与葡萄、大豆等植物的相似度较高,在第80~185氨基酸间含一个LEA-2蛋白保守结构域。荧光定量PCR结果表明,AgNHL基因主要在芹菜茎中表达,根中表达量最低,有明显组织特异性,品种差异也很显著。对2种芹菜分别进行4℃低温、38℃高温、20%PEG处理、0.2 mol/L NaCl处理2 h表达分析显示,低温、盐处理下该基因表达量明显上升。     

Very large trypomastigotes as a morphological pattern of strains of Trypanosoma cruzi in the southern region of Brazil

The morphological patterns of blood trypomastigotes from five sylvatic Trypanosoma cruzi strains from Santa Catarina, South Brazil, were studied during the course of infection in experimentally infected mice. A predominance of stout trypomastigotes (greater than 70%) was observed during all over the acute phase in four strains of medium virulence. With the remaining strain, of high virulence, the slender forms predominating at the early infection stage were soon also replaced by stout forms. Since almost all T. cruzi strains displaying predominance of this peculiar morphological pattern have been isolated in South Brazil (Rio Grande do Sul, Santa Catarina) and since there are evidences pointing out to the existence of biological differences among these distinct blood parasites, the authors suggest further investigations of possible correlations between the morphological markers and clinical-epidemiological aspects of Chagas' disease.     

Molecular characterization and expression analysis of interferon- inducible protein 56 gene in large yellow croaker Pseudosciaena crocea

In mammals, interferon-inducible protein 56 (IFI56) has been considered to play a role in mediating inhibition of viral replication and cell growth, and possibly in mediating cell apoptosis. Here, we reported the cloning of an IFI56 homologue from the spleen of large yellow croaker, a marine fish (LycIFI56). The complete cDNA of LycIFI56 gene is 1628 nucleotides (nt) encoding a protein of 437 amino acids (aa), with a putative molecular weight of 50.8 kDa. The deduced LycIFI56 protein has a high-level homology with all members of IFIT (IFN-inducible proteins with TPR domain) family, and its 9 putative TPR motifs all locate the corresponding position of these IFIT proteins. Phylogenetic analysis showed that five fish IFIT members form a unique clad independent of mammalian homologues, reflecting a distant evolutionary relationship from mammals. LycIFI56 gene was constitutively expressed in various tissues examined, such as gills, intestine, liver, kidney, heart, spleen, muscle and blood. Upon induction with poly(I:C), LycIFI56 gene expression is obviously up-regulated in spleen, gills, intestine, liver and kidney at 24 h post-induction, suggesting that LycIFI56 may be involved in the immune response induced by poly(I:C). Analysis of the expression kinetics of LycIFI56 and IRF1 genes revealed that the up-regulation of LycIRF-1 expression by poly (I:C) was apparently earlier than that of LycIFI56. These results would facilitate a better understanding of the expression regulation of fish IFI56 gene, and of its roles in immunity of bony fish.     

Expression pattern of a hematopoietic proteoglycan core protein gene during human hematopoiesis

Expression of the hematopoietic proteoglycan core protein (HpPG) gene was examined in normal peripheral blood, normal bone marrow, and leukemic peripheral blood leukocytes samples to assess the expression pattern of the HpPG gene in these cells and to ascertain points of regulation of this gene during hematopoiesis. In situ hybridization to normal bone marrow and peripheral blood leukocytes demonstrated that the gene was expressed in the promyelocytes at a approximately two fold greater level than in the segmented neutrophils and the expression decreased as the granulocytes matured. The ratio of expression in the other leukocytes to expression in the segmented neutrophils were as follows: eosinophils/basophils approximately 7; monocytes approximately 2; lymphocytes less than 1. Expression of the HpPG gene during myeloblast differentiation was assessed by Northern blot analysis of acute myelogenous leukemia (AML) RNA samples. The expression of this gene, when compared to the levels in HL-60 cells, was approximately ten fold lower in the poorly differentiated blast cells obtained from three AML patients classified M"0". Conversely, the expression in the more differentiated blast cells obtained from 10 of 11 AML patients classified as M1 and M2 were at levels similar to the levels in HL-60 cells. The expression level found in eight lymphoid leukemias was approximately ten fold or more lower than in HL-60 cells. Gene copy number determination confirmed that the HpPG gene is present in one copy per haploid genome. Thus the HpPG gene's expression pattern denotes a single copy gene being differentially expressed during hematopoiesis with initial regulation occurring very early in this developmental process and an additional up-regulatory event occurring during granule genesis.     

西番莲PeERG基因克隆及其表达模式分析

ERA(Eecherichia coli Ras-like protein)蛋白是与已知异三聚体G蛋白和小分子G蛋白不同的一种新的GTP结合蛋白。为了在木本植物中开展其同源基因ERG(ERA-like GTPase)克隆和功能验证的相关研究,该文首次在西番莲新品种‘平塘1号’中采用cDNA末端快速克隆(RACE)技术克隆鉴定1个ERG基因。结果表明:西番莲PeERG基因cDNA全长为1 518 bp,包括1 260 bp的开放阅读框、38 bp的5'-端非翻译区和220 bp的3'-端非翻译区,该基因编码蛋白由420个氨基酸残基组成,其二级结构含有丰富的α-螺旋和延伸链。PeERG蛋白不含跨膜区域,也不存在信号肽酶切位点,既在其N端有典型的GTPase保守结构域(GTPase domain)又在其C端有独特的RNA结合结构域(KH domain)。系统进化树分析表明,西番莲PeERG蛋白和水稻OsERG1、拟南芥AtERG1、大肠杆菌ERA位于同一进化分枝。实时定量PCR检测揭示PeERG基因在西番莲根、茎、叶、花、果中均有表达,叶中表达最高;同时该基因响应低温胁迫信号,其表达呈动态变化模式。该研究首次鉴定和描述了木本植物西番莲的ERG基因,为深入挖掘西番莲特异基因资源提供参考,也有助于进一步探究ERG基因在植物中的生物学功能及其作用机制。     

大豆PM34基因生物信息学预测及表达分析

以大豆叶片总RNA为模板,采用RT-PCR法从吉豆2号品种中克隆获得大豆种子成熟蛋白( PM34)基因序列,利用生物信息学方法对大豆PM34基因编码的蛋白进行预测。结果表明：该基因编码蛋白理论分子量为31.7 kDa,等电点为6.60,为亲水性蛋白;该蛋白中无跨膜结构;该蛋白中不存在信号肽。 PM34基因编码蛋白的二级结构中α螺旋占12.97％,无规则卷曲占41.30％,β折叠占45.73％。 PM34基因编码蛋白的三级结构预测表明,同源模建的模板是3ijr.1.A,是一种短链脱氢酶/还原酶,与该蛋白的同源性为54.65％。在进化关系上,与绿豆、苜蓿的亲缘关系相对较近。采用实时定量PCR方法( qRT-PCR),检测大豆PM34基因在大豆各器官中的表达方式,结果表明该基因在大豆根、茎、叶、花中的表达活性低,而在种子中,尤其是成熟种子中的相对表达活性很高。该研究结果为大豆PM34基因结构和功能的进一步研究奠定了基础。     

Why protein R-factors are so large: a self-consistent analysis

The R-factor and R-free are commonly used to measure the quality of protein models obtained in X-ray crystallography. Well-refined protein structures usually have R-factors in the range of 20-25%, whereas intrinsic errors in the experimental data are usually around 5%. We use molecular dynamics simulations to perform a self-consistent analysis by which we determine the major factors contributing to large values of protein R-factors. The analysis shows that significant R-factor values can arise from the use of isotropic B-factors to model anisotropic protein motions and from coordinate errors. Even in the absence of coordinate errors, the use of isotropic B-factors can cause the R-factors to be around 10%; for coordinate errors smaller than 0.2 A, the two errors types make similar contributions. The inaccuracy of the energy function used and multistate protein dynamics are unlikely to make significant contributions to the large R-factors.     

Lists2Networks: Integrated analysis of gene/protein lists

Background  

Systems biologists are faced with the difficultly of analyzing results from large-scale studies that profile the activity of many genes, RNAs and proteins, applied in different experiments, under different conditions, and reported in different publications. To address this challenge it is desirable to compare the results from different related studies such as mRNA expression microarrays, genome-wide ChIP-X, RNAi screens, proteomics and phosphoproteomics experiments in a coherent global framework. In addition, linking high-content multilayered experimental results with prior biological knowledge can be useful for identifying functional themes and form novel hypotheses.