Volume 517 Issue 7536


Senate vs science p.527

A few Republicans agreeing with basic climate research is not an environmental victory.

doi: 10.1038/517527b

Human history defies easy stories p.527

The discovery of part of a 55,000-year-old human skull in Israel will help to answer some questions about our species' evolution — but it shows that the tale is complicated.

doi: 10.1038/517527a

Technical support p.528

Technicians are often under appreciated, but without them there could be no research.

doi: 10.1038/517528a


News Features

News & Views

Emergency back-up for lung repair p.556

Influenza virus severely damages the epithelial tissue that lines the lung. Findings suggest that, in mice, activation of a back-up population of stem cells mediates effective repair of the injured lung. See Letters p.616 & p.621

doi: 10.1038/517556a

Stellar clocks p.557

A link between rotation and age for Sun-like stars has long been known, but a stringent test of it for older stars has been lacking. The Kepler mission helps to fill this gap with observations of an old star cluster. See Letter p.589

doi: 10.1038/517557a

Seeing the wood and the trees p.558

The identification of the gene regulatory network that controls the formation of xylem — the major component of wood — opens up new avenues for manipulating plant biomass. See Article p.571

doi: 10.1038/nature14085

Relativity tested with a split electron p.559

Splitting and recombining an electron wave packet has been used to test relativity at a record sensitivity. The result heralds an era of precision measurements of relativity using quantum-information methods. See Letter p.592

doi: 10.1038/517559a

CRISPR engineering turns on genes p.560

The repurposing of a bacterial defence system known as CRISPR into a potent activator of gene expression in human cells enables powerful studies of gene function, as exemplified in cancer cells. See Article p. 583

doi: 10.1038/517560a

Free and forced climate variations p.562

A combination of simulations and data shows that short-term climate trends are dominated by natural internal variations, providing a basis for climate forecasting, but not for assessing sensitivity to forced changes. See Article p.565

doi: 10.1038/517562a

Risk factors and random chances p.563

The discovery that the estimated number of stem-cell divisions in a tissue correlates with cancer incidence suggests that the varying probability of developing cancer in different tissues is mostly down to random mutations.

doi: 10.1038/517563a


Forcing, feedback and internal variability in global temperature trends p.565

A study of the effect of radiative forcing, climate feedback and ocean heat uptake on global-mean surface temperature indicates that overestimation of the response of climate models to radiative forcing from increasing greenhouse gas concentrations is not responsible for the post-1998 discrepancy between model simulations and observations.

doi: 10.1038/nature14117

An Arabidopsis gene regulatory network for secondary cell wall synthesis p.571

The full complement of transcriptional regulators that affect synthesis of the plant secondary cell wall remains largely undetermined; here, the network of protein–DNA interactions controlling secondary cell wall synthesis of Arabidopsis thaliana is determined, showing that gene expression is regulated by a series of feed-forward loops to ensure that the secondary cell wall is deposited at the right time and in the right place.

doi: 10.1038/nature14099

Comprehensive genomic characterization of head and neck squamous cell carcinomas OPEN p.576

The Cancer Genome Atlas presents an integrative genome-wide analysis of genetic alterations in 279 head and neck squamous cell carcinomas (HNSCCs), which are classified by human papillomavirus (HPV) status; alterations in EGFR, FGFR, PIK3CA and cyclin-dependent kinases are shown to represent candidate targets for therapeutic intervention in most HNSCCs.

doi: 10.1038/nature14129


A spin-down clock for cool stars from observations of a 2.5-billion-year-old cluster p.589

The measurement of the rotational periods of 30 cool stars in the 2.5-billion-year-old cluster NGC 6819 allows the calibration of gyrochronology — the determination of a star’s age on the basis of its rotation period — over a much broader age range than hitherto, meaning that it might be possible to determine the ages of many cool stars in the Galactic field with a precision of roughly 10 per cent.

doi: 10.1038/nature14118

Michelson–Morley analogue for electrons using trapped ions to test Lorentz symmetry p.592

An electronic analogue of a Michelson–Morley experiment, in which an electron wave packet bound inside a calcium ion is split into two parts and subsequently recombined, demonstrates that the relative change in orientation of the two parts that results from the Earth’s rotation reveals no anisotropy in the electron dispersion; this verification of Lorentz symmetry improves on the precision of previous tests by a factor of 100.

doi: 10.1038/nature14091

Anomalous dispersions of ‘hedgehog’ particles p.596

Micrometre-sized particles covered with stiff, nanoscale spikes are shown to exhibit long-term colloidal stability in both hydrophilic and hydrophobic media, without the need for chemical coating, owing to the effect of the spikes on the contact area and, consequently, the force between the particles.

doi: 10.1038/nature14092

Effects of electron correlations on transport properties of iron at Earth’s core conditions p.605

Based on first-principles resistivity calculations, it was recently concluded that the thermal conductivity of iron in Earth’s core was too high to sustain thermal convection, thus invalidating such geodynamo models; new calculations including electron correlations find that electron–electron scattering is comparable to the electron–phonon scattering at high temperatures in iron, doubling the expected resistivity, and reviving conventional geodynamo models.

doi: 10.1038/nature14090

Resolving the complexity of the human genome using single-molecule sequencing p.608

Single-molecule, real-time DNA sequencing is used to analyse a haploid human genome (CHM1), thus closing or extending more than half of the remaining 164 euchromatic gaps in the human genome; the complete sequences of euchromatic structural variants (including inversions, complex insertions and tandem repeats) are resolved at the base-pair level, suggesting that a greater complexity of the human genome can now be accessed.

doi: 10.1038/nature13907

Interception of host angiogenic signalling limits mycobacterial growth p.612

Using a model of tuberculosis in zebrafish, granuloma formation is shown to coincide with hypoxia and angiogenesis; furthermore, the pharmacological inhibition of the pro-angiogenic VEGF pathway reduces infection burden, suggesting a possible treatment strategy in patients with the disease.

doi: 10.1038/nature13967

p63+Krt5+ distal airway stem cells are essential for lung regeneration p.616

Lung diseases such as chronic obstructive pulmonary disease and pulmonary fibrosis involve the progressive and inexorable destruction of oxygen exchange surfaces and airways, and have emerged as a leading cause of death worldwide. Mitigating therapies, aside from impractical organ transplantation, remain limited and the possibility of regenerative medicine has lacked empirical support. However, it is clinically known that patients who survive sudden, massive loss of lung tissue from necrotizing pneumonia or acute respiratory distress syndrome often recover full pulmonary function within six months. Correspondingly, we recently demonstrated lung regeneration in mice following H1N1 influenza virus infection, and linked distal airway stem cells expressing Trp63 (p63) and keratin 5, called DASCp63/Krt5, to this process. Here we show that pre-existing, intrinsically committed DASCp63/Krt5 undergo a proliferative expansion in response to influenza-induced lung damage, and assemble into nascent alveoli at sites of interstitial lung inflammation. We also show that the selective ablation of DASCp63/Krt5 in vivo prevents this regeneration, leading to pre-fibrotic lesions and deficient oxygen exchange. Finally, we demonstrate that single DASCp63/Krt5-derived pedigrees differentiate to type I and type II pneumocytes as well as bronchiolar secretory cells following transplantation to infected lung and also minimize the structural consequences of endogenous stem cell loss on this process. The ability to propagate these cells in culture while maintaining their intrinsic lineage commitment suggests their potential in stem cell-based therapies for acute and chronic lung diseases.

doi: 10.1038/nature13903

Lineage-negative progenitors mobilize to regenerate lung epithelium after major injury p.621

Lineage-tracing experiments identify a rare, undifferentiated population of quiescent cells in the mouse distal lung that are activated through a Notch signalling pathway to repair the epithelium after bleomycin- or influenza-mediated injury; inappropriate Notch signalling may be a major contributor to failed regeneration within the lungs of patients with chronic lung disease.

doi: 10.1038/nature14112