オバマ米大統領は、気候変動問題に足跡を残したいなら、もっと踏み込んだエネルギー政策を打ち出すべきだ。
Change for good p.577
The United States must boost energy spending to make its mark on the climate debate.
doi: 10.1038/493577b
Volume 493 Number 7434
今週のハイライト
Cover Story: そっとひとなで：なでられるのが快感となる訳を説明する「マッサージ」ニューロン
物性: 凝縮物質における新しい「hastatic」秩序
細胞: ミトコンドリア遺伝子の置換
構造生物学: スプライソソームの作用機構の解明
宇宙: 惑星の行く末を探る
材料: 生体模倣高分子ネットワーク
環境: 後退する熱帯の泥炭地帯
遺伝: ヒアリでは社会性染色体が女王の数を支配する
細胞: Rag GTPアーゼはmTORC1のための栄養センサー
細胞: リンゴ酸酵素とp53の相互作用
構造生物学: V1-ATPアーゼの回転機構
- OUTLOOK: 心臓の健康
目次
Editorials
厳しい財政状況の下、政府や助成機関は、よく似た内容の研究に重複して助成することのないよう、もっと留意すべきだ。
Twice the price p.577
Governments and funding agencies must do more to prevent the awarding of grants to research projects with significant overlap.
doi: 10.1038/493577a
気球は大気観測に大いに役立っており、宇宙探査への活用にも期待が膨らむ。
Inflatable friends p.578
Research balloons have taught us much about the atmosphere, and could now fly into space.
doi: 10.1038/493578a
News
EUが「未来と最先端技術」計画による巨額の助成対象を、ヒト脳マップ研究とグラフェン研究に決定。
Research prize boost for Europe p.585
Graphene and virtual brain win billion-euro competition.
doi: 10.1038/493585a
英国の7つの公的研究助成機関に、統合の可能性が。
UK research councils could face mergers p.586
Wide-ranging review edges towards single funding pot.
doi: 10.1038/493586a
中米のコーヒーに大打撃を与えるさび病菌の流行を阻止しようと、さまざまな研究が。
Coffee rust regains foothold p.587
Researchers marshal technology in bid to thwart fungal outbreak in Central America.
doi: 10.1038/493587a
助成の重複を避けるには、選考過程でのチェックが課題に。
Funding agencies urged to check for duplicate grants p.588
Nature probe reveals lack of oversight of researchers who win two grants for similar projects.
doi: 10.1038/493588a
電気でなく磁気で切り替わるトランジスターの利用で、可変型のチップが。
Magnetic logic makes for mutable chips p.589
Alternative transistor relies on exotic semiconductor.
doi: 10.1038/493589a
米国オバマ政権が、温暖化対策に力を入れる姿勢を。
Obama rekindles climate hopes p.590
President will use regulations to sidestep stalled Congress.
doi: 10.1038/493590a
News Features
惑星科学：現場をキャッチ
Planetary science: Caught in the act p.592
斉一説を揺るがすことだが、我々は今、太陽系のつかの間の壮大なスペクタクルを目にしているかもしれない。
doi: 10.1038/493592a
海洋保全：小さな魚をめぐる大きな闘い
Ocean conservation: A big fight over little fish p.597
漁業資源管理では、これまで魚の大きさによる制限が行われてきたが、かえって害があるとの疑問が生じている。
doi: 10.1038/493597a
News & Views
フォーラム：遺伝学：社会的な再編成
Genetics: A social rearrangement p.612
ヒアリのワーカーの一部は、そのコロニーに複数匹の女王を許容するが、これら以外のワーカーは、女王を1匹しか受け入れない。このような行動の違いは、まれな染色体対上にある遺伝子クラスターによって制御されていることが明らかになった。この知見が社会性の進化や遺伝学などの研究分野に持つ意味について、2人の研究者が見解を述べている。
doi: 10.1038/nature11854
太陽物理学：よみがえった惑星仮説
Solar physics: The planetary hypothesis revived p.613
太陽の磁気活動は、ほぼ11年を一区切りとして周期的に変動している。この活動について新たに得られた、時間的に幅を持った代わりの記録の分析は、惑星がこの周期の振幅に影響を及ぼす可能性を示唆している。
doi: 10.1038/493613a
構造生物学：明らかになったスプライソソームの核心部分
Structural biology: Spliceosome's core exposed p.615
スプライソソーム複合体は、転写されたRNAからイントロン塩基配列を除去してメッセンジャーRNAを作り出す。スプライソソームを構成するタンパク質の1つのPrp8の構造から、複合体の活性部位が明らかになり、スプライシングの起源について手がかりが得られた。
doi: 10.1038/nature11857
生物地球化学：窒素循環の深さ
Biogeochemistry: The depths of nitrogen cycling p.616
海洋の溶存有機窒素の分解は、海表面付近にいる微生物の領分だと考えられてきた。だが、このような微生物が分解には向かないことがわかり、窒素プールの生物地球化学的性質に再検討が必要となっている。
doi: 10.1038/493616a
材料科学：生物のような硬さを持つ合成ポリマー
Materials science: Synthetic polymers with biological rigidity p.618
生細胞に含まれるポリマーと同じような硬さのブラシ状ポリマーが合成され、これを使って力応答性の材料が作られた。こうした進歩は、薬剤送達や生体組織工学への応用への道を開くだろう。
doi: 10.1038/nature11855
物性物理学：謎は深まるばかり
Condensed-matter physics: Hidden is more p.619
ウランを使った材料の隠れた電子秩序は、数十年にわたって物理学研究者の頭を悩ませてきた。新たな理論研究は、それが時間反転対称性の1回の破れだけではなく、二重の破れに起因するとしている。
doi: 10.1038/493619a
Articles
物性：重いフェルミオン化合物URu2Si2のhastatic秩序
Hastatic order in the heavy-fermion compound URu2Si2 p.621
The development of collective long-range order by means of phase transitions occurs by the spontaneous breaking of fundamental symmetries. Magnetism is a consequence of broken time-reversal symmetry, whereas superfluidity results from broken gauge invariance. The broken symmetry that develops below 17.5 kelvin in the heavy-fermion compound URu2Si2 has long eluded such identification. Here we show that the recent observation of Ising quasiparticles in URu2Si2 results from a spinor order parameter that breaks double time-reversal symmetry, mixing states of integer and half-integer spin. Such ‘hastatic’ order hybridizes uranium-atom conduction electrons with Ising 5f
doi: 10.1038/nature11820
細胞：遺伝性ミトコンドリア病の生殖系列遺伝子治療に向けて
Towards germline gene therapy of inherited mitochondrial diseases p.627
Mutations in mitochondrial DNA (mtDNA) are associated with severe human diseases and are maternally inherited through the egg’s cytoplasm. Here we investigated the feasibility of mtDNA replacement in human oocytes by spindle transfer (ST; also called spindle–chromosomal complex transfer). Of 106 human oocytes donated for research, 65 were subjected to reciprocal ST and 33 served as controls. Fertilization rate in ST oocytes (73%) was similar to controls (75%); however, a significant portion of ST zygotes (52%) showed abnormal fertilization as determined by an irregular number of pronuclei. Among normally fertilized ST zygotes, blastocyst development (62%) and embryonic stem cell isolation (38%) rates were comparable to controls. All embryonic stem cell lines derived from ST zygotes had normal euploid karyotypes and contained exclusively donor mtDNA. The mtDNA can be efficiently replaced in human oocytes. Although some ST oocytes displayed abnormal fertilization, remaining embryos were capable of developing to blastocysts and producing embryonic stem cells similar to controls.
doi: 10.1038/nature11647
細胞：ヒト卵母細胞の核ゲノム移植によるミトコンドリアDNA変異の除去
Nuclear genome transfer in human oocytes eliminates mitochondrial DNA variants p.632
Mitochondrial DNA mutations transmitted maternally within the oocyte cytoplasm often cause life-threatening disorders. Here we explore the use of nuclear genome transfer between unfertilized oocytes of two donors to prevent the transmission of mitochondrial mutations. Nuclear genome transfer did not reduce developmental efficiency to the blastocyst stage, and genome integrity was maintained provided that spontaneous oocyte activation was avoided through the transfer of incompletely assembled spindle–chromosome complexes. Mitochondrial DNA transferred with the nuclear genome was initially detected at levels below 1%, decreasing in blastocysts and stem-cell lines to undetectable levels, and remained undetectable after passaging for more than one year, clonal expansion, differentiation into neurons, cardiomyocytes or β-cells, and after cellular reprogramming. Stem cells and differentiated cells had mitochondrial respiratory chain enzyme activities and oxygen consumption rates indistinguishable from controls. These results demonstrate the potential of nuclear genome transfer to prevent the transmission of mitochondrial disorders in humans.
doi: 10.1038/nature11800
構造生物学：Prp8の結晶構造から明らかになったスプライソソーム活性部位の空洞
Crystal structure of Prp8 reveals active site cavity of the spliceosome p.638
The active centre of the spliceosome consists of an intricate network formed by U5, U2 and U6 small nuclear RNAs, and a pre-messenger-RNA substrate. Prp8, a component of the U5 small nuclear ribonucleoprotein particle, crosslinks extensively with this RNA catalytic core. Here we present the crystal structure of yeast Prp8 (residues 885–2413) in complex with Aar2, a U5 small nuclear ribonucleoprotein particle assembly factor. The structure reveals tightly associated domains of Prp8 resembling a bacterial group II intron reverse transcriptase and a type II restriction endonuclease. Suppressors of splice-site mutations, and an intron branch-point crosslink, map to a large cavity formed by the reverse transcriptase thumb, and the endonuclease-like and RNaseH-like domains. This cavity is large enough to accommodate the catalytic core of group II intron RNA. The structure provides crucial insights into the architecture of the spliceosome active site, and reinforces the notion that nuclear pre-mRNA splicing and group II intron splicing have a common origin.
doi: 10.1038/nature11843
Letters
宇宙：古い円盤も惑星系を形成することが可能である
An old disk still capable of forming a planetary system p.644
In combination with existing observations and detailed circumstellar models, the detection of hydrogen deuteride emission from the star TW Hydrae implies a circumstellar disk mass of more than 0.05 solar masses, which is enough to form a planetary system like our own.
doi: 10.1038/nature11805
工学：三次元スピントロニクスメモリーと論理用の磁気ラチェット
Magnetic ratchet for three-dimensional spintronic memory and logic p.647
A layered on-chip structure of magnetic thin films is engineered to permit the vertical transfer of magnetic information over near-atomic distances.
doi: 10.1038/nature11733
材料：ポリイソシアノペプチド・ヒドロゲルから形成される応答性生体模倣ネットワーク
Responsive biomimetic networks from polyisocyanopeptide hydrogels p.651
Thermal transitions of polyisocyanide single molecules to polymer bundles and finally networks lead to hydrogels mimicking the properties of biopolymer intermediate-filament networks; their analysis shows that bundling and chain stiffness are crucial design parameters for hydrogels.
doi: 10.1038/nature11839
気候：自然強制か人為起源の強制かによって異なる全球の降水変化
Divergent global precipitation changes induced by natural versus anthropogenic forcing p.656
Palaeoproxy evidence shows that the sea-surface-temperature gradient across the tropical Pacific Ocean strengthened during the Medieval Warm Period but weakens in model-projected future warming; this is because solar radiation induces greater precipitation for the same temperature change than greenhouse gases.
doi: 10.1038/nature11784
環境：河川の有機炭素流量から明らかになった森林破壊を受けた熱帯泥炭地帯の深刻な不安定性
Deep instability of deforested tropical peatlands revealed by fluvial organic carbon fluxes p.660
Riverine carbon-14 measurements show that anthropogenic disturbance of peat swamp forest in southeast Asia is causing increased release of carbon that has been stored in the peat for thousands of years.
doi: 10.1038/nature11818
遺伝：ヒアリではY染色体に似た社会性染色体が異なるコロニー構成を生じさせる
A Y-like social chromosome causes alternative colony organization in fire ants p.664
Fire ants (Solenopsis invicta) are socially polymorphic, with some workers tolerating several queens in their colony and others tolerating just one; this study shows that a non-recombining supergene is responsible for this social polymorphism, and the operation of this genomic region is remarkably similar to that of sex chromosomes.
doi: 10.1038/nature11832
生理：有毛皮膚へのマッサージ様ストローキングを検知するC繊維のin vivoでの遺伝学的同定
Genetic identification of C fibres that detect massage-like stroking of hairy skin in vivo p.669
Calcium imaging in live mice shows that a rare population of unmyelinated sensory neurons—expressing the G-protein-coupled receptor MRGPRB4—responds specifically to massage-like stroking of hairy skin, with positive reinforcing behavioural effects.
doi: 10.1038/nature11810
医学：NLRP3はアルツハイマー病で活性化され、APP/PS1マウスの病態に寄与する
NLRP3 is activated in Alzheimer’s disease and contributes to pathology in APP/PS1 mice p.674
Alzheimer’s-prone mice deficient in NLRP3 or caspase-1 fail to develop learning deficits and show reduced neuropathology.
doi: 10.1038/nature11729
細胞：Rag GTPアーゼによるmTORC1の調節は新生仔のオートファジーと生存に必要である
Regulation of mTORC1 by the Rag GTPases is necessary for neonatal autophagy and survival p.679
Mice expressing a constitutively active form of RagA are unable to inhibit mTORC1 after birth and to trigger autophagy, and succumb perinatally.
doi: 10.1038/nature11745
免疫：脾臓の辺縁帯B細胞のシャトリングと濾胞B細胞流出の可視化
Visualization of splenic marginal zone B-cell shuttling and follicular B-cell egress p.684
Lymphocyte migration in the spleen is visualized live in mice using a real-time two-photon laser-scanning microscopy approach revealing that marginal zone and follicular B cells are highly motile and can shuttle between compartments, and integrin adhesion is the key to cellular retention in the marginal zone.
doi: 10.1038/nature11738
細胞：p53とリンゴ酸酵素による相反的な調節が代謝と老化を調節する
Reciprocal regulation of p53 and malic enzymes modulates metabolism and senescence p.689
Evidence for a link between cellular senescence and metabolic regulation is provided, through the observation that p53 represses the expression of malic enzymes, thereby regulating NADPH, lipid and glutamine metabolism; in turn, this repression further activates p53, promoting cellular senescence.
doi: 10.1038/nature11776
遺伝：系統発生上の保存と分岐のパターンを利用した、低分子RNA経路遺伝子の同定
Identification of small RNA pathway genes using patterns of phylogenetic conservation and divergence p.694
To identify comprehensively factors involved in RNAi and microRNA-mediated gene expression regulation, this study performed a phylogenetic analysis of 86 eukaryotic species; the candidates this approach highlighted were subjected to Bayesian analysis with transcriptional and proteomic interaction data, identifying protein orthologues of already known RNAi silencing factors, as well as other hits involved in splicing, suggesting a connection between the two processes.
doi: 10.1038/nature11779
構造生物学：ヒト基本転写因子TFIIDコア複合体の構造
The architecture of human general transcription factor TFIID core complex p.699
The structures of three distinct human transcription factor IID (TFIID) protein assemblies are solved using cryo-electron microscopy; by incorporating TAF8 and TAF10, the key structural changes that remodel TFIID during assembly are determined, particularly the transition from a symmetric core-TFIID to an asymmetric holo-complex.
doi: 10.1038/nature11791
構造生物学：Enterococcus hiraeのV1-ATPアーゼの非対称な結晶構造に基づく回転機構
Rotation mechanism of Enterococcus hirae V1-ATPase based on asymmetric crystal structures p.703
Several crystal structures of the rotary motor of bacterial V-ATPase are solved at high resolution, representing different asymmetric structures and enabling the prediction of a model for the rotational mechanism of V1-ATPase.
doi: 10.1038/nature11778
