Volume 521 Number 7551

Editorials

Challenging times p.125

A European initiative to ban animal research has galvanized resistance.

doi: 10.1038/521125b

A nation with ambition p.125

India is making great strides in improving its science, but it needs to look carefully at its approach and work with the rest of the world if it is to realize its full potential.

doi: 10.1038/521125a

Polls apart p.126

The UK voter opinion polls show that an anomalous answer can be the correct one.

doi: 10.1038/521126a

News

News Features

Science in India p.141

A special issue explores the enormous potential and major challenges for research in south Asia's superpower.

doi: 10.1038/521141a

The anti-bureaucrat p.148

K. VijayRaghavan is determined to cut through red tape and build up biological science in India.

doi: 10.1038/521148a

News & Views

The slow death of red galaxies p.164

For most galaxies, the shutdown of star formation was a slow process that took 4 billion years. An analysis of some 27,000 galaxies suggests that 'strangulation' by their environment was the most likely cause. See Letter p.192

doi: 10.1038/521164a

Internal compass puts flies in their place p.165

An analysis reveals that fruit-fly neurons orient flies relative to cues in the insects' environment, providing evidence that the fly's brain contains a key component for drawing a cognitive map of the insect's surroundings. See Article p.186

doi: 10.1038/521165a

Fungus against the wall p.168

A compound derived from plant cell-wall material that is a waste product of biofuel manufacture has been found to have fungicidal properties: it interacts with a carbohydrate called β1,3 glucan, thus compromising the integrity of fungal cells.

doi: 10.1038/521168a

Steps on the road to eukaryotes p.169

A new archaeal phylum represents the closest known relatives of eukaryotes, the group encompassing all organisms that have nucleated cells. The discovery holds promise for a better understanding of eukaryotic origins.

doi: 10.1038/nature14522

Rap and chirp about X inactivation p.170

Two new techniques identify proteins that directly interact with a non-protein-coding RNA called Xist to mediate inactivation of one X chromosome in female mammals. See Letter p.232

doi: 10.1038/521170a

Articles

Complex archaea that bridge the gap between prokaryotes and eukaryotes p.173

This study identifies a clade of archaea that is the immediate sister group of eukaryotes in phylogenetic analyses, and that also has a repertoire of proteins otherwise characteristic of eukaryotes—proteins that would have provided the first eukaryotes with a ‘starter kit’ for the genomic and cellular complexity characteristic of the eukaryotic cell.

doi: 10.1038/nature14447

Neurons for hunger and thirst transmit a negative-valence teaching signal p.180

Cell-type-specific electrical activity manipulations and deep-brain imaging in mice of neuronal populations associated with homeostasis of nutrient or fluid intake reveals that learning is conditioned by a negative-valence signal from the hunger-mediating AGRP neurons and also from the thirst-mediating neurons in the subfornical organ.

doi: 10.1038/nature14416

Neural dynamics for landmark orientation and angular path integration p.186

Calcium imaging of the brain of tethered flies walking in a virtual reality arena showed that a population of neurons with dendrites that tile the ‘ellipsoid body’ use information from visual landmarks and the fly's own rotation to compute heading; this suggests insects possess neurons with similarities to ‘head direction cells’ known to contribute to spatial navigation in mammalian brains.

doi: 10.1038/nature14446

Letters

Electron pairing without superconductivity p.196

Evidence is presented for electron pairing in strontium titanate far above the superconducting transition temperature; such pairs are thought to be the long-sought pre-formed pairs that condense at lower temperatures to give rise to the unconventional superconducting state in this system.

doi: 10.1038/nature14398

YAP is essential for tissue tension to ensure vertebrate 3D body shape p.217

D’Arcy Thompson predicted a century ago that animal body shape is conditioned by gravity, but there has been no animal model to study how cellular forces are coordinated to generate body shapes that withstand gravity; the hirame medaka fish mutant, with pronounced body flattening, reveals how the hirame/YAP gene controls gravity-resisting cellular forces to produce complex 3D organs and body shapes.

doi: 10.1038/nature14215

The Xist lncRNA interacts directly with SHARP to silence transcription through HDAC3 p.232

The mechanisms by which Xist, a long non-coding RNA, silences one X chromosome in female mammals are unknown; here a mass spectrometry-based approach is developed to identify several proteins that interact directly with Xist, including the transcriptional repressor SHARP that is required for transcriptional silencing through the histone deacetylase HDAC3.

doi: 10.1038/nature14443

Horizontal membrane-intrinsic α-helices in the stator a-subunit of an F-type ATP synthase p.237

ATP, the universal energy currency of cells, is produced by F-type ATP synthases, which are ancient, membrane-bound nanomachines. F-type ATP synthases use the energy of a transmembrane electrochemical gradient to generate ATP by rotary catalysis. Protons moving across the membrane drive a rotor ring composed of 8–15 c-subunits. A central stalk transmits the rotation of the c-ring to the catalytic F1 head, where a series of conformational changes results in ATP synthesis. A key unresolved question in this fundamental process is how protons pass through the membrane to drive ATP production. Mitochondrial ATP synthases form V-shaped homodimers in cristae membranes. Here we report the structure of a native and active mitochondrial ATP synthase dimer, determined by single-particle electron cryomicroscopy at 6.2 Å resolution. Our structure shows four long, horizontal membrane-intrinsic α-helices in the a-subunit, arranged in two hairpins at an angle of approximately 70° relative to the c-ring helices. It has been proposed that a strictly conserved membrane-embedded arginine in the a-subunit couples proton translocation to c-ring rotation. A fit of the conserved carboxy-terminal a-subunit sequence places the conserved arginine next to a proton-binding c-subunit glutamate. The map shows a slanting solvent-accessible channel that extends from the mitochondrial matrix to the conserved arginine. Another hydrophilic cavity on the lumenal membrane surface defines a direct route for the protons to an essential histidine–glutamate pair. Our results provide unique new insights into the structure and function of rotary ATP synthases and explain how ATP production is coupled to proton translocation.

doi: 10.1038/nature14185