Volume 528 Number 7581

Editorials

Fetal tissue research under threat p.163

The US Senate has just voted to defund one of the providers of aborted fetal tissue for research. Such research is too valuable to become embroiled in the bitter abortion debate.

doi: 10.1038/528163a

Stem the tide p.163

Japan has introduced an unproven system to make patients pay for clinical trials.

doi: 10.1038/528163b

Future-proofing p.164

Hard decisions on issues that will affect future generations should not be sidestepped.

doi: 10.1038/528164a

News

News Features

The truth about fetal tissue research p.178

The use of aborted fetal tissue has sparked controversy in the United States, but many scientists say it is essential for studies of HIV, development and more.

doi: 10.1038/528178a

The last illness p.182

Researchers are gaining insight into the causes of a devastating form of muscle wasting that is often the final stage of cancer and other diseases.

doi: 10.1038/528182a

News & Views

A last-minute decision p.196

Robust quantitative analyses of asymmetric division in certain cells in flies identify the major molecular players and, most interestingly, define a simple equation to explain this complex cellular process. See Letter p.280

doi: 10.1038/528196a

The complexity of intimacy p.197

Catalysts that contain two types of active site split long hydrocarbon molecules into more-useful shorter ones. Research into controlling the nanoscale separation of the sites challenges accepted design rules for such catalysts. See Letter p.245

doi: 10.1038/528197a

Cure by killing p.198

Two bi-specific protein constructs have been designed that direct the body's T cells to kill HIV-infected cells. The feat provides a step on the path to removing the latent virus reservoir that persists in patients on antiretroviral therapy.

doi: 10.1038/nature16321

The Sun and the rain p.200

A study shows that, as Earth warms, global precipitation will increase by less than many models predict, because of increases in the amount of near-infrared sunlight absorbed by water vapour. See Letter p.249

doi: 10.1038/528200a

Architecture of a protein entry gate p.201

The TOM complex guides precursor proteins from the cell's cytosolic fluid into organelles called mitochondria. Biochemical analyses reveal the architecture of this complex and show how precursor proteins pass through its narrow pores.

doi: 10.1038/nature16318

How the Solar System didn't form p.202

Standard planet-formation models have been unable to reconstruct the distributions of the Solar System's small, rocky planets and asteroids in the same simulation. A new analysis suggests that it cannot be done.

doi: 10.1038/nature16322

A transcriptional specialist resolved p.204

Three structures of the enzyme RNA polymerase III, which is responsible for the synthesis of abundant short RNAs, reveal the specializations that make it an adept terminator and reinitiator of transcription. See Article p.231

doi: 10.1038/nature16317

In the right place at the right time p.205

Regulatory T cells help to prevent autoimmune responses. A new imaging technique reveals that activation of these cells requires clustering with self-reactive effector T cells and sensing of the signalling protein interleukin-2. See Article p.225

doi: 10.1038/nature16312

Articles

Undecidability of the spectral gap p.207

The spectral gap problem—whether the Hamiltonian of a quantum many-body problem is gapped or gapless—is rigorously proved to be undecidable; there exists no algorithm to determine whether an arbitrary quantum many-body model is gapped or gapless, and there exist models for which the presence or absence of a spectral gap is independent of the axioms of mathematics.

doi: 10.1038/nature16059

Signal integration by Ca2+ regulates intestinal stem-cell activity p.212

Drosophila intestinal stem cells (ISCs) respond to changes in diet, particularly L-glutamate levels, by modulating Ca2+ signalling to adapt their proliferation rate; furthermore, Ca2+ is shown to be central to the response of ISCs to a wide range of dietary and stress stimuli.

doi: 10.1038/nature16170

The histone chaperone CAF-1 safeguards somatic cell identity p.218

RNA interference screens were used to identify chromatin-associated factors that impede reprogramming of somatic cells into iPS cells; suppression of the chromatin assembly factor CAF-1 enhances the generation of iPS cells by rendering chromatin more accessible to pluripotency transcription factors.

doi: 10.1038/nature15749

Molecular structures of unbound and transcribing RNA polymerase III p.231

RNA polymerase III (Pol III), the largest eukaryote polymerase yet characterized, transcribes structured small non-coding RNAs; here cryo-electron microscopy structures of budding yeast Pol III allow building of an atomic-level model of the complete 17-subunit complex, both unbound and while elongating RNA.

doi: 10.1038/nature16143

Letters

Sublimation in bright spots on (1) Ceres p.237

The dwarf planet (1) Ceres, the largest object in the main asteroid belt, is found to have localized bright areas on its surface; particularly interesting is a bright pit on the floor of the crater Occator that exhibits what is likely to be water ice sublimation, producing crater-bound haze clouds with a diurnal rhythm.

doi: 10.1038/nature15754

An observational radiative constraint on hydrologic cycle intensification p.249

The magnitude of global precipitation increase predicted by climate models has a large uncertainty that has been difficult to constrain, but much of the range in predictions is now shown to arise from shortcomings in the modelling of atmospheric absorption of shortwave radiation; if the radiative transfer algorithms controlling the absorption were more accurate, the model spread would narrow and the mean estimate could be about 40% lower.

doi: 10.1038/nature15770

The ontogeny of fairness in seven societies p.258

An analysis of when children develop a sense of fairness (receiving less or more than a peer) is compared across seven different societies; aversion to receiving less emerges early in childhood in all societies, whereas aversion to receiving more emerges later in childhood and only in three of the seven societies studied.

doi: 10.1038/nature15703

Disentangling type 2 diabetes and metformin treatment signatures in the human gut microbiota p.262

Growing evidence from metagenome-wide association studies link multiple common disorders to microbial dysbiosis but effects of drug treatment are often not accounted for; here, the authors re-analyse two previous metagenomic studies of type 2 diabetes mellitus patients together with a novel cohort to determine the effects of the widely prescribed antidiabetic drug metformin and highlight the need to distinguish the effects of a disease from the effects of treatment on the gut microbiota.

doi: 10.1038/nature15766

Force generation by skeletal muscle is controlled by mechanosensing in myosin filaments p.276

It is widely accepted that contraction of skeletal muscle and the heart involves structural changes in actin-containing thin filaments to allow binding of myosin motors from neighbouring thick filaments, thus driving filament sliding; here, X-ray diffraction of single skeletal muscle cells reveals that this thin-filament mechanism can regulate muscle contraction against low load, but high-load contraction requires a second permissive step involving a structural change in the thick filament.

doi: 10.1038/nature15727

Replication stress activates DNA repair synthesis in mitosis p.286

Common fragile sites (CFSs) are difficult-to-replicate regions of eukaryotic genomes that are sensitive to replication stress and that require resolution by the MUS81–EME1 endonuclease to re-initiate POLD3-dependent DNA synthesis in early mitosis; this study defines the specific pathway of events causing the CFS fragility phenotype.

doi: 10.1038/nature16139