Volume 509 Number 7498

Editorials

False positives p.7

A correlation between error rate and success undermines promise of stem-cell trials.

doi: 10.1038/509007b

No magic fix for carbon p.7

Carbon capture and storage projects promise to make a dent in global emissions — but only as part of a broader programme of technology deployment and economic incentives.

doi: 10.1038/509007a

Agency for change p.8

Japan’s proposed reforms to science monitoring are welcome but long overdue.

doi: 10.1038/509008a

News

News Features

Smallpox watch p.22

Frozen mummies and envelopes of scabs could contain remnants of one of history's most prolific killers.

doi: 10.1038/509022a

News & Views

Drought in the Congo Basin p.36

A remote-sensing analysis of tropical forests in the Congo Basin that are experiencing chronic drought reveals consistent patterns of reduced vegetation greenness, increased temperatures and decreased water storage. See Letter p.86

doi: 10.1038/nature13330

Bright electron twisters p.37

A new holographic method has been used to convert ordinary electron beams into helical beams. These beams show promise in applications such as the spectroscopic analysis of materials with intrinsic handedness and nanoparticle manipulation.

doi: 10.1038/509037a

Feedback throttled down for smooth moves p.38

A group of regulatory neurons in the spinal cord has been found to reduce sensory feedback to muscles in mice. Removal of these neurons leads to repetitive limb oscillations during reaching. See Article p.43

doi: 10.1038/509038a

Making the Earth move p.40

Controversy exists over the roles of water and melt in the ductile layer of the mantle beneath Earth's surface plates. New data support models in which small amounts of melting occur in the uppermost part of this region. See Letter p.81

doi: 10.1038/509040a

A new spin on exoplanets p.41

Spectroscopic observations of a young exoplanet have allowed its spin velocity to be directly measured. Its fast spin is in accord with the extrapolation of the known trend in spin velocity as a function of planet mass. See Letter p.63

doi: 10.1038/509041a

Articles

Presynaptic inhibition of spinal sensory feedback ensures smooth movement p.43

A population of spinal interneurons that form axo–axonic connections with the terminals of proprioceptive afferents are shown to mediate presynaptic inhibition; their ablation elicits harmonic oscillations during goal-directed forelimb movements, which can be modelled as the consequence of an increase in sensory feedback gain.

doi: 10.1038/nature13276

Haematopoietic stem cells require a highly regulated protein synthesis rate p.49

Haematopoietic stem cells (HSCs) have a lower rate of protein synthesis in vivo than most other haematopoietic cells, and both increases and decreases in the rate of protein synthesis impair HSC function, demonstrating that HSC maintenance—and hence, cellular homeostasis—requires the rate of protein synthesis to be highly regulated.

doi: 10.1038/nature13035

Letters

Fast spin of the young extrasolar planet β Pictoris b p.63

The spin of a planet arises from the accretion of angular momentum during its formation, but the details of this process are still unclear. In the Solar System, the equatorial rotation velocities and, consequently, spin angular momenta of most of the planets increase with planetary mass; the exceptions to this trend are Mercury and Venus, which, since formation, have significantly spun down because of tidal interactions. Here we report near-infrared spectroscopic observations, at a resolving power of 100,000, of the young extrasolar gas giant planet β Pictoris b (refs 7, 8). The absorption signal from carbon monoxide in the planet’s thermal spectrum is found to be blueshifted with respect to that from the parent star by approximately 15 kilometres per second, consistent with a circular orbit. The combined line profile exhibits a rotational broadening of about 25 kilometres per second, meaning that β Pictoris b spins significantly faster than any planet in the Solar System, in line with the extrapolation of the known trend in spin velocity with planet mass.

doi: 10.1038/nature13253

Molecular photons interfaced with alkali atoms p.66

Single organic dye molecules have high-flux, narrow-bandwidth single-photon emission and can be spectrally matched to the transitions of atoms acting as a quantum memory, making them promising for use in quantum information and communication schemes.

doi: 10.1038/nature13191

North Atlantic forcing of tropical Indian Ocean climate p.76

New sea surface temperature and oxygen isotope records, combined with climate modelling experiments, show that slowdowns of the Atlantic meridional overturning circulation during Heinrich stadials and the Younger Dryas stadial affected the tropical Indian Ocean hydroclimate through changes to the Hadley circulation.

doi: 10.1038/nature13196

Cystathionine γ-lyase deficiency mediates neurodegeneration in Huntington's disease p.96

Huntington’s disease is an autosomal dominant disease associated with a mutation in the gene encoding huntingtin (Htt) leading to expanded polyglutamine repeats of mutant Htt (mHtt) that elicit oxidative stress, neurotoxicity, and motor and behavioural changes. Huntington’s disease is characterized by highly selective and profound damage to the corpus striatum, which regulates motor function. Striatal selectivity of Huntington’s disease may reflect the striatally selective small G protein Rhes binding to mHtt and enhancing its neurotoxicity. Specific molecular mechanisms by which mHtt elicits neurodegeneration have been hard to determine. Here we show a major depletion of cystathionine γ-lyase (CSE), the biosynthetic enzyme for cysteine, in Huntington’s disease tissues, which may mediate Huntington’s disease pathophysiology. The defect occurs at the transcriptional level and seems to reflect influences of mHtt on specificity protein 1, a transcriptional activator for CSE. Consistent with the notion of loss of CSE as a pathogenic mechanism, supplementation with cysteine reverses abnormalities in cultures of Huntington’s disease tissues and in intact mouse models of Huntington’s disease, suggesting therapeutic potential.

doi: 10.1038/nature13136

Structural basis for ubiquitin-mediated antiviral signal activation by RIG-I p.110

RIG-I protein recognizes viral duplex RNA with a 5′-triphosphate group, activating innate immune responses; a crystal structure of its tetrameric CARD signalling domain reveals that non-covalently linked ubiquitin chains stabilize the tetramer in a ‘lock-washer’ structure that serves as a signalling platform for the recruitment and activation of MAVS.

doi: 10.1038/nature13140

Agonist-bound structure of the human P2Y12 receptor p.119

An X-ray structure of human P2Y12 receptor, a clinical drug target for platelet aggregation inhibitors, is presented in complex with an agonist, providing insight into the δ-group of class A G-protein-coupled receptors.

doi: 10.1038/nature13288