コムギ染色体欠損系統を用いた新規活性型レトロトランスポゾン TriRe-1 の分子遺伝学的解析

　Retrotransposons constitute the large fraction (～80%) of the wheat genome where numerous and diverse retrotransposon families exist, where especially the long terminal repeat (LTR) retrotransposon family is known to be predominant. Thus, they have been considered to contribute to the genome expansion, sequence diversification and the genome structure alternation in the wheat genome. In addition, the insertion polymorphism of the LTR retrotransposon family among the cultivars has been known to be quite useful for the genetic analysis such as the linkage mapping and the phylogenetic studies. Here, we report the characteristics of a novel active LTR retrotransposon family TriRe‒1, which belongs to the Ty1‒copia group in the hexaploid wheat (Triticum aestivum L.) genome. This retroelement appears to encode all proteins required for the transposition and showed high insertion polymorphism among the hexaploid wheat cultivars, suggesting its potential of transpositional activity with at least recent transposition during wheat evolution. We studied the chromosomal localization of the TriRe‒1 insertion site based on the genome-wide comparative analysis using the nullisomic-tetrasomic lines of the cultivar Chinese Spring. The results showed that although the majority of the TriRe‒1 insertion sites exist across the homoeologous chromosomes of A, B or D genomes, a higher number of insertions in the B genome was detected compared to A or D genome, suggesting a specific amplification in the history of B genome progenitors. In conclusion, a novel LTR retrotransposon TriRe‒1 should be valuable for the development of molecular markers based on insertion polymorphism among the cultivars, and also the genome-specific TriRe‒1 insertion site can be utilized to study evolutional history of wheat genomes.　レトロトランスポゾンは植物ゲノムの主要な構成要素であり，コムギゲノムにおいてはその80ｵを占める．特に LTR 型レトロトランスポゾンの割合が高く，ゲノムの拡大，配列の多様性およびゲノム構造変異等に大きく寄与し てきたと考えられている．これら配列は自身のコピー配列を複製し増幅するため，ゲノム中には数百，数千に及ぶコ ピー配列をもつ．また，ゲノム進化の過程において多数のファミリーを形成してきた．これら多数のファミリーのう ち，現在でも転移活性を示す活性型ファミリーは，品種間において高い挿入多型を示すことが知られている．このよ うな挿入多型は，連鎖解析および系統解析等各種遺伝解析に利用可能である. 本研究では，コムギにおける新規活性 型レトロトランスポゾンファミリー TriRe-1 の特徴を詳細に解析した．TriRe-1 は転移に必要なタンパク質をコー ドする内部配列をもち，また日本で育成されたコムギ近縁品種間においても高い挿入多型を示したため，現在でも転 移活性を有している，もしくはごく最近まで転移していた可能性が高いと考えられた．一方で，コムギ染色体欠損系 統（ナリソミックテトラソミック系統）を用い，TriRe-1 の挿入箇所を比較解析した．その結果，大部分の挿入箇所 は複数の同祖染色体に存在すると考えられたが，Ｂゲノムにおいて最も多くの特異的な挿入箇所が同定された．よっ て，Ｂゲノム祖先種において活発に増幅してきた可能性が示唆された．今回の結果により，新規活性型レトロトラン スポゾン TriRe-1 の品種間挿入多型を利用した DNA マーカー，また，各ゲノム（Ａ，Ｂ，Ｄゲノム）特異的な挿 入箇所を利用したゲノム識別性に優れた DNA マーカーの開発の可能性が期待される

Proposal of utilizing uni-directional porous copper for extremely high heat flux removal

This paper proposes new heat removal devices utilizing uni-directional porous copper against extremely high heat flux conditions. Before designing those, we discuss some key parameters of porous media to enable a high heat flux removal over 10 MW/m2 at a low flow rate of water, which are effective thermal conductivity, permeability, liquid supply to a heat transfer surface, and contact thermal resistance between the porous medium and the heat transfer surface. These discussions indicate utilizing the uni-directional porous media as shown in Fig. 1 from the view point of its higher thermal conductivity, direct supply of cooling liquid toward the heat transfer surface, discharge of vapor, reduction in flow resistance and the thermal contact resistance Please download the full abstract below

Genome-wide identification and gene expression profiling of ubiquitin ligases for endoplasmic reticulum protein degradation

Endoplasmic reticulum (ER)-associated degradation (ERAD) is a mechanism by which unfolded proteins that accumulate in the ER are transported to the cytosol for ubiquitin–proteasome-mediated degradation. Ubiquitin ligases (E3s) are a group of enzymes responsible for substrate selectivity and ubiquitin chain formation. The purpose of this study was to identify novel E3s involved in ERAD. Thirty-seven candidate genes were selected by searches for proteins with RING-finger motifs and transmembrane regions, which are the major features of ERAD E3s. We performed gene expression profiling for the identified E3s in human and mouse tissues. Several genes were specifically or selectively expressed in both tissues; the expression of four genes (RNFT1, RNF185, CGRRF1 and RNF19B) was significantly upregulated by ER stress. To determine the involvement of the ER stress-responsive genes in ERAD, we investigated their ER localisation, in vitro autoubiquitination activity and ER stress resistance. All were partially localised to the ER, whereas CGRRF1 did not possess E3 activity. RNFT1 and RNF185, but not CGRRF1 and RNF19B, exhibited significant resistance to ER stressor in an E3 activity-dependent manner. Thus, these genes are possible candidates for ERAD E3s.This study was supported by Grants-in-Aid for Scientific Research (KAKENHI) 15K21706, 26460099, 24300135, 22020032, 25251014, 15K15067, 15K20001, 15K18377 and 15K19516 from the Ministry of Education, Culture, Sports, Science and Technology, Japan and also supported by the Takeda Science Foundation. We thank H. Hishigaki and Otsuka GEN Research Institute for bioinformatic analysis. We also thank M. Minami and T. Uehara for the helpful discussions. We are grateful to T. Yoshikawa, T. Ike, Y. Maeoka, Y. Wada and Z. Cao for their technical assistance. The authors would like to thank Enago (www.enago.jp) for the English language review

A Bicyclic 1-Deoxygalactonojirimycin Derivative as a Novel Pharmacological Chaperone for GM1 Gangliosidosis

Lysosomal β-galactosidase (β-Gal) deficiency causes a group of disorders that include neuronopathic GM1 gangliosidosis and non-neuronopathic Morquio B disease. We have previously proposed the use of small molecule ligands of β-Gal as pharmacological chaperones (PCs) for the treatment of GM1 gangliosidosis brain pathology. Although it is still under development, PC therapy has yielded promising preclinical results in several lysosomal diseases. In this study, we evaluated the effect of bicyclic 1-deoxygalactonojirimycin (DGJ) derivative of the sp2-iminosugar type, namely 5N,6S-(N′-butyliminomethylidene)-6-thio-1- deoxygalactonojirimycin (6S-NBI-DGJ), as a novel PC for human mutant β-Gal. In vitro, 6S-NBI-DGJ had the ability to inhibit the activity of human β-Gal in a competitive manner and was able to protect this enzyme from heat-induced degradation. Computational analysis supported that the rigid glycone bicyclic core of 6S-NBI-DGJ binds to the active site of the enzyme, with the aglycone N′-butyl substituent, in a precise E-orientation, located at a hydrophobic region nearby. Chaperone potential profiling indicated significant increases of enzyme activity in 24 of 88 β-Gal mutants, including four common mutations. Finally, oral administration of 6S-NBI-DGJ ameliorated the brain pathology of GM1 gangliosidosis model mice. These results suggest that 6S-NBI-DGJ is a novel PC that may be effective on a broad range of β-Gal mutants.Ministerio de Ciencia e Innovación de España. SAF2010-15670 y CTQ2010-15848Junta de Andalucía. P08-FQM-0371

Her yol Roma'ya varmaz!

Taha Toros Arşivi, Dosya Adı: Taha Torosİstanbul Kalkınma Ajansı (TR10/14/YEN/0033) İstanbul Development Agency (TR10/14/YEN/0033

Fructo-oligosaccharides ameliorate steatohepatitis, visceral adiposity, and associated chronic inflammation via increased production of short-chain fatty acids in a mouse model of non-alcoholic steatohepatitis

Background: Non-alcoholic fatty liver disease (NAFLD) is a hepatic manifestation of metabolic syndrome. Within the spectrum of NAFLD, non-alcoholic steatohepatitis (NASH) in combination with hepatic inflammation and fibrosis can lead to liver cirrhosis and hepatocellular carcinoma. Dysbiosis was reported to contribute to NASH pathogenesis. This study aimed to determine the effects of fructo-oligosaccharides (FOS) on steatohepatitis and visceral adiposity in an obese mouse model of NASH. Methods: Twelve newborn C57BL/6 J male mice were subcutaneously injected with monosodium glutamate (MSG) to induce obesity on a conventional diet. Six mice were also administered 5% FOS via drinking water from 10 weeks of age. At 18 weeks, histological characteristics of the liver and epididymal fat were compared between the groups. Hepatic mRNA expression of lipid metabolism enzymes and SCFA in feces and sera were measured. Results: Hepatic steatosis, inflammatory cell infiltration, and hepatocyte ballooning in the liver and increased hepatic mRNA expression of fatty acid synthase and glycerol-3-phosphate acyltransferase were observed in the MSG-treated mice. FOS treatment improved the liver pathology and blunted the increases in the mRNA expression levels of lipid metabolism enzymes. In addition, FOS inhibited adipocyte enlargement and formation of crown-like structures and reduced the M1 macrophage frequency in the epididymal fat of the MSG mice (39.4% ± 3.0% vs. 22.8% ± 0.7%; P = 0.001). FOS increased not only the fecal concentrations of n-butyric acid (0.04 ± 0.01 vs. 0.38 ± 0.14 mg/g, P = 0.02), propionic acid (0.09 ± 0.03 vs. 0.42 ± 0.16 mg/g, P = 0.02), and acetic acid (0.65 ± 0.16 vs. 1.48 ± 0.29 mg/g, P = 0.03) but also the serum concentration of propionic acid (3.9 ± 0.5 vs. 8.2 ± 0.5 μmol/L, P = 0.001). Conclusions: FOS ameliorates steatohepatitis, visceral adiposity, and chronic inflammation by increasing SCFA production

Update on the Keio collection of Escherichia coli single-gene deletion mutants

The Keio collection (Baba et al, 2006) has been established as a set of single‐gene deletion mutants of Escherichia coli K‐12. These mutants have a precisely designed deletion from the second codon from the seventh to the last codon of each predicted ORF. Further information is available at http://sal.cs.purdue.edu:8097/GB7/index.jsp or http://ecoli.naist.jp/. The distribution is now being handled by the National Institute of Genetics of Japan (http://www.shigen.nig.ac.jp/ecoli/pec/index.jsp). To date more than 4 million samples have been distributed worldwide. As we described earlier (Baba et al, 2006), gene amplification during construction is likely to have led to a small number of mutants with genetic duplications

Systematic phenome analysis of Escherichia coli multiple-knockout mutants reveals hidden reactions in central carbon metabolism

Central carbon metabolism is a basic and exhaustively analyzed pathway. However, the intrinsic robustness of the pathway might still conceal uncharacterized reactions. To test this hypothesis, we constructed systematic multiple-knockout mutants involved in central carbon catabolism in Escherichia coli and tested their growth under 12 different nutrient conditions. Differences between in silico predictions and experimental growth indicated that unreported reactions existed within this extensively analyzed metabolic network. These putative reactions were then confirmed by metabolome analysis and in vitro enzymatic assays. Novel reactions regarding the breakdown of sedoheptulose-7-phosphate to erythrose-4-phosphate and dihydroxyacetone phosphate were observed in transaldolase-deficient mutants, without any noticeable changes in gene expression. These reactions, triggered by an accumulation of sedoheptulose-7-phosphate, were catalyzed by the universally conserved glycolytic enzymes ATP-dependent phosphofructokinase and aldolase. The emergence of an alternative pathway not requiring any changes in gene expression, but rather relying on the accumulation of an intermediate metabolite may be a novel mechanism mediating the robustness of these metabolic networks