米国の「がんムーンショット」計画ではプロジェクトの選考が重大な課題になっているが、すでに確立された予防法は確実に推進すべきだ。

US Cancer Moonshot must strike a balance between research and prevention p.467

In the face of uncertain funding, the US initiative should not ignore proven programmes in favour of glitzy research.

doi: 10.1038/539467a

ビッグデータによって医療に変革を起こすには、データを使いこなせる手法と人材が必要だ。

The power of big data must be harnessed for medical progress p.467

But grave challenges remain before the promise of individually tailored medicine becomes reality.

doi: 10.1038/539467b

資金不足により最低限の施設環境での稼働が決まったヨルダンのSESAMEだが、交流の場なくしては国を超えた中東の科学研究の発展という本来の目的は果たせない。

Middle East X-ray factory is a source of hope p.468

The SESAME synchrotron shows a way towards greater trust and cooperation in the Middle East.

doi: 10.1038/539468a

中東のSESAMEシンクロトロンが間もなく稼働のときを迎えるが、現在資金の問題が。

First Middle Eastern X-ray factory readies for action p.475

SESAME project is set to revolutionize science in the region but is strapped for cash.

doi: 10.1038/539475a

米国大統領選でトランプ氏が勝利したことで、移民科学者とマイノリティーの科学者に不安が。

Immigrant and minority scientists shaken by Trump win p.476

Worries include job prospects, discrimination — and safety.

doi: 10.1038/539476a

恐竜絶滅をもたらしたとされる小惑星衝突で生じたクレーターの掘削調査によって、衝突の状況と影響が明らかに。

Rock core from dinosaur-killing impact reveals how enormous craters form p.478

Drilling into Mexico’s Chicxulub basin also finds shattered rock where underground life could thrive.

doi: 10.1038/nature.2016.20994

中国の研究チームが、CRISPRゲノム編集法を用いた新しいがん治療法の臨床試験を。

CRISPR gene-editing tested in a person for the first time p.479

The move by Chinese scientists could spark a biomedical duel between China and the United States.

doi: 10.1038/nature.2016.20988

ブラジルで、政府の科学予算を今後20年現状維持とする憲法修正案にブラジルの研究者が抗議を。

Brazil’s scientists battle to escape 20-year funding freeze p.480

Cap at current spending levels could spell ‘end of science in Brazil’, researchers say.

doi: 10.1038/nature.2016.21014

遺伝学者たちが、コウモリの発声のカギを握る遺伝子を明らかにするためのプロジェクト「Bat 1K」を発表。

Geneticists hope to unlock secrets of bats’ complex sounds p.481

Project to sequence the DNA of more than 1,000 species seeks to reveal how bats learn to communicate.

doi: 10.1038/nature.2016.20997

進化：4つの性を持つ鳥

The sparrow with four sexes p.482

スズメの仲間であるノドジロシトドが持つ奇妙な染色体を長年にわたって調べてきたRusty GonserとElaina Tuttleという研究者夫妻の日々をたどる。

doi: 10.1038/539482a

DNA修復：コピーの誤りを取り締まる

DNA repair: Clamping down on copy errors p.498

修復酵素がDNA複製の間に生じた誤りを取り除くには、数百の塩基と広く情報交換を行わなくてはならない。複製酵素が輪状の締め金に似た複合体を複数作り、それをDNAに沿って拡散移動させることでこうした情報交換を行うことが、画像化により明らかにされた。

doi: 10.1038/nature20475

材料科学：電荷を流れやすくする高分子

Materials science: Polymers make charge flow easy p.499

有機半導体デバイスは、導電材料との良好な電気的接触を必要とするが、そのような接触は効率が悪いことが多い。この問題を解決する方法が今回開発され、これは広範囲にわたる応用が可能となりそうだ。

doi: 10.1038/539499a

進化：昆虫の侵入と自然選択

Evolution: Insect invasions and natural selection p.500

トウヨウミツバチのオーストラリアへの侵入がリアルタイムで観察された。それによって、自然選択がどのように働いて、小規模の創始者集団の定着成功を妨げるような数々の遺伝学的困難を乗り越えさせるのか、その状況が明らかになった。

doi: 10.1038/nature20472

ナノ科学：柔軟なグラフェンで見られる摩擦強化

Nanoscience: Flexible graphene strengthens friction p.502

グラフェン上での摩擦は、プローブがグラフェンの表面上を滑り始めてから徐々に増加していくことが、以前の観察により明らかになっている。今回行われたシミュレーションで、この摩擦強化がグラフェンシートの曲がりに関連していることが分かった。

doi: 10.1038/539502a

細胞生物学：血管修復にブレーキをかけるミトコンドリア

Cell biology: A mitochondrial brake on vascular repair p.503

傷ついた血管は血管平滑筋細胞によって修復される。タンパク質のFat1が、ミトコンドリアの機能阻害により、このような細胞の増殖を調節していることが今回明らかになった。

doi: 10.1038/nature20476

材料科学：ナノ粒子の画像を改良する

Materials science: Improving the image of nanoparticles p.505

蛍光性のナノダイヤモンドと金ナノ粒子を結合させた生体適合性のプローブを使うと、光学顕微鏡法と電子顕微鏡法の両方で細胞を画像化することが可能になる。このプローブは生物学研究に従来なかったような展開をもたらすだろう。

doi: 10.1038/nature20478

植物科学：細菌が葉に侵入する際に起こる水をめぐる闘い

Plant science: A war over water when bacteria invade leaves p.506

細菌が植物に感染する際に、両者の間では「制水権」をめぐって闘いが起こるらしい。これは、植物細胞を操作して、水を多く含んでいて細菌の増殖を促進する環境を作り出す細菌種の研究から明らかになった。

doi: 10.1038/539506a

物性物理学：表面と界面におけるスピン–軌道結合に誘起された創発的な現象

Emergent phenomena induced by spin–orbit coupling at surfaces and interfaces p.509

The interplay between spin–orbit coupling and two-dimensionality has led to the emergence of new phases of matter, such as spin-polarized surface states in topological insulators, interfacial chiral spin interactions, and magnetic skyrmions in thin films, with great potential for spin-based devices.

doi: 10.1038/nature19820

パターン形成：齧歯類の縞模様の発生機構

Developmental mechanisms of stripe patterns in rodents p.518

Alx3-induced modulation of Mitf expression alters melanocyte differentiation and gives rise to the hair colour differences underlying the repeated evolution of dorsal stripes in rodents.

doi: 10.1038/nature20109

植物科学：細菌は植物体内で毒力に不可欠な水性生息空間を確立する

Bacteria establish an aqueous living space in plants crucial for virulence p.524

A combination of high humidity and bacterial effectors, such as Pseudomonas syringae HopM1, creates an aqueous environment in the apoplast of immunodeficient Arabidopsis thaliana that allows non-pathogenic P. syringae strains to become virulent pathogens.

doi: 10.1038/nature20166

細胞微生物学：細菌のフォーカルアドヒージョン複合体での力伝達機構

The mechanism of force transmission at bacterial focal adhesion complexes p.530

The mystery of how bacteria that lack motile structures such as pili or flagella can ‘glide’ along surfaces is solved by a detailed description of the bacterial focal adhesion complex and its associated protein machinery.

doi: 10.1038/nature20121

材料科学：オーミック接触用の極めて高い仕事関数と極めて低い仕事関数を持つドープ高分子半導体

Doped polymer semiconductors with ultrahigh and ultralow work functions for ohmic contacts p.536

A general strategy for producing solution-processed doped polymers with the extreme work functions that are required to make good ohmic contacts to semiconductors is demonstrated in high-performance light-emitting diodes, transistors and solar cells.

doi: 10.1038/nature20133

材料科学：グラフェンとの摩擦接触の質の経時変化

The evolving quality of frictional contact with graphene p.541

Atomistic simulations reproduce experimental observations of transient frictional strengthening of graphene on an amorphous silicon substrate, an effect which diminishes as the number of graphene layers increases.

doi: 10.1038/nature20135

有機化学：シクロペンタノンの炭素–炭素結合の触媒的活性化

Catalytic activation of carbon–carbon bonds in cyclopentanones p.546

In the chemical industry, it is often necessary to activate carbon–carbon bonds in order to synthesize complex organic molecules, but this is challenging when starting with simple five- or six-membered carbon rings; a new method uses a rhodium pre-catalyst and an amino-pyridine co-catalyst, enabling an overall energetically favourable reaction that involves activation of carbon–carbon bonds plus activation of carbon–hydrogen bonds.

doi: 10.1038/nature19849

地球磁気学：惑星ダイナモ波に起因する磁場反転

Magnetic reversals from planetary dynamo waves p.551

Polarity reversals caused by dynamo waves are demonstrated in a magnetohydrodynamic model that is relevant to planetary cores, suggesting a possible mechanism of geomagnetic reversals.

doi: 10.1038/nature19842

学習と記憶：ミトコンドリアと記憶をつなぐカンナビノイド

A cannabinoid link between mitochondria and memory p.555

Cannabinoids affect CB₁ receptors on the mitochondrial membranes in the brain, triggering a decrease in downstream cAMP-dependent signalling; this leads to a decrease in brain mitochondrial activity and to cannabinoid-induced amnesia.

doi: 10.1038/nature20127

幹細胞：腸幹細胞およびオルガノイド培養のためのデザイナーマトリックス

Designer matrices for intestinal stem cell and organoid culture p.560

The authors have designed modular synthetic hydrogel networks for mouse and human intestinal stem cell cultures that support intestinal organoid formation.

doi: 10.1038/nature20168

免疫学：多様な組織マクロファージはアポトーシス細胞を取り込むことで異なる恒常性プログラムを誘導する

Different tissue phagocytes sample apoptotic cells to direct distinct homeostasis programs p.565

Apoptotic intestinal epithelial cells can be sampled by lamina propria phagocytes, leading to distinct phagocyte-type-specific anti-inflammatory gene signatures and dendritic-cell-mediated induction of regulatory T cells.

doi: 10.1038/nature20138

免疫学：マクロファージはノンプロフェッショナル食細胞によるファゴサイトーシスを切り替え、炎症に影響を与える

Macrophages redirect phagocytosis by non-professional phagocytes and influence inflammation p.570

Macrophage-derived insulin-like growth factor enhances the uptake of microvesicles by non-professional phagocytes, such as airway epithelial cells and fibroblasts, thereby dampening tissue inflammation.

doi: 10.1038/nature20141

細胞生物学：非典型的カドヘリンFat1によるミトコンドリア機能と細胞増殖の制御

Control of mitochondrial function and cell growth by the atypical cadherin Fat1 p.575

Fragments of the atypical cadherin Fat1 accumulate in the mitochondria of vascular smooth muscle cells where they reduce respiration, leading to a regulated proliferative response to arterial injury.

doi: 10.1038/nature20170

エネルギー代謝：呼吸鎖複合体IIIおよびIVの超集合機構

Mechanism of super-assembly of respiratory complexes III and IV p.579

SCAF1 is always required for the interaction between the respiratory chain complexes III and IV, and in animals carrying only the short isoform of SCAF1, the respirasome is absent in most tissues, with the exception of heart and skeletal muscle, where COX7A2 is present instead of SCAF1.

doi: 10.1038/nature20157

DNA修復：MutSおよびMutLのスライディングクランプによるカスケードがDNA上での拡散を制御してミスマッチ修復を始動させる

Cascading MutS and MutL sliding clamps control DNA diffusion to activate mismatch repair p.583

MutS and MutL—the highly conserved core proteins responsible for the repair of mismatched DNA—form sequential stable sliding clamps that together modulate one-dimensional diffusion along the DNA and, with MutH, facilitate the search for a distant excision initiation site.

doi: 10.1038/nature20562

分子生物学：piRNAの3′末端の形成の遺伝的および機構的な多様性

Genetic and mechanistic diversity of piRNA 3′-end formation p.588

Small regulatory RNAs guide Argonaute (Ago) proteins in a sequence-specific manner to their targets and therefore have important roles in eukaryotic gene silencing. Of the three small RNA classes, microRNAs and short interfering RNAs are processed from double-stranded precursors into defined 21- to 23-mers by Dicer, an endoribonuclease with intrinsic ruler function. PIWI-interacting RNAs (piRNAs)—the 22–30-nt-long guides for PIWI-clade Ago proteins that silence transposons in animal gonads—are generated independently of Dicer from single-stranded precursors. piRNA 5′ ends are defined either by Zucchini, the Drosophila homologue of mitoPLD—a mitochondria-anchored endonuclease, or by piRNA-guided target cleavage. Formation of piRNA 3′ ends is poorly understood. Here we report that two genetically and mechanistically distinct pathways generate piRNA 3′ ends in Drosophila. The initiating nucleases are either Zucchini or the PIWI-clade proteins Aubergine (Aub) or Ago3. While Zucchini-mediated cleavages directly define mature piRNA 3′ ends, Aub/Ago3-mediated cleavages liberate pre-piRNAs that require extensive resection by the 3′-to-5′ exoribonuclease Nibbler (Drosophila homologue of Mut-7). The relative activity of these two pathways dictates the extent to which piRNAs are directed to cytoplasmic or nuclear PIWI-clade proteins and thereby sets the balance between post-transcriptional and transcriptional silencing. Notably, loss of both Zucchini and Nibbler reveals a minimal, Argonaute-driven small RNA biogenesis pathway in which piRNA 5′ and 3′ ends are directly produced by closely spaced Aub/Ago3-mediated cleavage events. Our data reveal a coherent model for piRNA biogenesis, and should aid the mechanistic dissection of the processes that govern piRNA 3′-end formation.