Trials in animals can aid both veterinary and human medicine, but complicated rules can stifle them.
Human activity causes most changes in Earth’s surface water, so policies for its governance must become a priority.
Books have the power to trigger a lifelong urge to know more about the world and its environs.
But the European Space Agency's participation in a mission to deflect an asteroid moon is now cancelled.
DNA proves Native American roots of 10,600-year-old skeleton.
Researchers in the country have only just started using homegrown human embryonic stem cells
Institutions struggle to respond after court blocks regulations that would have increased wages for junior researchers.
Illegal land clearing hits highest levels since 2008 as environmental policies come under attack.
Economic woes wrought by globalization are only part of the cause.
Investigation of a 150-year-old burial site is helping to unlock the mysteries of one of humanity’s darkest chapters.
News & Views
Global sea levels would rise by several metres if the Greenland Ice Sheet melted completely. Two studies have examined its past behaviour in an effort to evaluate its vulnerability in a warming world — and have come to seemingly conflicting conclusions. Two geochemists and a glaciologist discuss the issues. See Letters p.252 & p.256
Viruses can be attacked by parasitic viruses, which compete with them for cellular resources. It emerges that one such parasitic virus can defend a host-cell population from a viral attack. See Letter p.288
The chemical composition of a massive galaxy in the early Universe reveals an extremely short period of star formation. This result could challenge our ideas about the evolution of galaxies and of the Universe itself. See Letter p.248
Electrical oscillations generated by neural circuits are disrupted in Alzheimer's disease. Restoring these oscillations in mouse models activates immune cells to clear disease-associated amyloid-β protein from the brain. See Article p.230
In 1976, it was demonstrated that tiny wobbles in Earth's orbit led to the great ice-age cycles of the past few million years. This finding had wide implications for climate science and the details remain hotly debated today.
Nuclear DNA from human eggs that harbour mutations in the DNA of organelles called mitochondria has been successfully transferred to donor eggs, bringing the prospect of therapy for mitochondrial diseases a step closer. See Letter p.270
Human stem cells that can give rise to every cell type in the body are major players in biomedical research. A molecular analysis of human embryos might help to make these cultured cells more authentic imitations of their in vivo counterparts.
Quantum technology enables new methods for generating of randomness with minimal assumptions, certified by the violation of a Bell inequality, which opens up new theoretical and experimental research directions and leads to new challenges.
Wild and managed pollinators are threatened by pressures such as environmental changes and pesticides, leading to risks for pollinator-dependent crop production, meaning more research and better policies are needed to safeguard pollinators and their services.
Mouse models of Alzheimer’s disease show reduced, behaviourally driven gamma oscillations before the onset of plaque formation or cognitive decline; driving neurons to oscillate at gamma frequency (40 Hz) reduces levels of amyloid-β peptides.
S-2-hydroxyglutarate produced by CD8+ T cells under hypoxic conditions affects locus-specific histone and DNA methylation patterns, which enhances T-cell proliferation, survival and recall responses.
One of the most abundant modifications found in messenger RNAs is N6-methyladenosine (m6A); here, this modification is shown to alter gene expression during sex determination and affect neuronal functions and behaviour in Drosophila via the m6A reader protein YT521-B.
The ratio of magnesium to iron abundance is measured for a massive quiescent galaxy at a redshift of 2.1, corresponding to when the Universe was three billion years old.
Measurements of cosmic-ray-produced 10Be and 26Al in a bedrock core from beneath the summit of the Greenland Ice Sheet show that Greenland was nearly ice-free for extended periods under Pleistocene climate forcing.
10Be and 26Al isotopic evidence in quartz sand from the seafloor shows that a dynamic East Greenland Ice Sheet has existed for the past 7.5 million years.
Seismic observations clarify the roles of magma pressure and tectonic stress in the development of seafloor spreading during the most recent eruption at the East Pacific Rise.
Analysis of a large grassland biodiversity dataset shows that increases in local land-use intensity cause biotic homogenization at landscape scale across microbial, plant and animal groups, both above- and belowground, that is largely independent of changes in local diversity.
Analysis of mitochondrial replacement therapy shows, even with efficient mutant mitochondrial DNA replacement and maintenance in embryonic stem cells, a gradual loss of donor mitochondrial DNA in some lines owing to a polymorphism in the D-loop, potentially causing preferential replication of specific mitochondrial DNA haplotypes.
Platelet-derived growth factor receptor α (PDGFRα) exhibits divergent effects in skeletal muscle. At physiological levels, signalling through this receptor promotes muscle development in growing embryos and angiogenesis in regenerating adult muscle. However, both increased PDGF ligand abundance and enhanced PDGFRα pathway activity cause pathological fibrosis. This excessive collagen deposition, which is seen in aged and diseased muscle, interferes with muscle function and limits the effectiveness of gene- and cell-based therapies for muscle disorders. Although compelling evidence exists for the role of PDGFRα in fibrosis, little is known about the cells through which this pathway acts. Here we show in mice that PDGFRα signalling regulates a population of muscle-resident fibro/adipogenic progenitors (FAPs) that play a supportive role in muscle regeneration but may also cause fibrosis when aberrantly regulated. We found that FAPs produce multiple transcriptional variants of Pdgfra with different polyadenylation sites, including an intronic variant that codes for a protein isoform containing a truncated kinase domain. This variant, upregulated during regeneration, acts as a decoy to inhibit PDGF signalling and to prevent FAP over-activation. Moreover, increasing the expression of this isoform limits fibrosis in vivo in mice, suggesting both biological relevance and therapeutic potential of modulating polyadenylation patterns in stem-cell populations.
Certain commensal enterobacteria secrete small proteins called microcins that suppress the growth of other bacteria in the inflamed gut, conferring an intra- and interspecies competitive advantage.
The development of immunologic interventions that can target the viral reservoir in HIV-1-infected individuals is a major goal of HIV-1 research. However, little evidence exists that the viral reservoir can be sufficiently targeted to improve virologic control following discontinuation of antiretroviral therapy. Here we show that therapeutic vaccination with Ad26/MVA (recombinant adenovirus serotype 26 (Ad26) prime, modified vaccinia Ankara (MVA) boost) and stimulation of TLR7 (Toll-like receptor 7) improves virologic control and delays viral rebound following discontinuation of antiretroviral therapy in SIV-infected rhesus monkeys that began antiretroviral therapy during acute infection. Therapeutic vaccination with Ad26/MVA resulted in a marked increase in the magnitude and breadth of SIV-specific cellular immune responses in virologically suppressed, SIV-infected monkeys. TLR7 agonist administration led to innate immune stimulation and cellular immune activation. The combination of Ad26/MVA vaccination and TLR7 stimulation resulted in decreased levels of viral DNA in lymph nodes and peripheral blood, and improved virologic control and delayed viral rebound following discontinuation of antiretroviral therapy. The breadth of cellular immune responses correlated inversely with set point viral loads and correlated directly with time to viral rebound. These data demonstrate the potential of therapeutic vaccination combined with innate immune stimulation as a strategy aimed at a functional cure for HIV-1 infection.
Endogenous viral elements found in a marine protozoan have a function in defence against infection by giant viruses.
Autonomously produced hybrid biological nanomaterials termed ‘enveloped protein nanocages’ incorporate features for membrane binding, self-assembly, and ESCRT recruitment for cellular release.
A conformation capture sequencing method is developed to link multiple genomic loci into three-dimensional proximity chains called chromosomal walks (C-walks), adding to our understanding of how higher-order chromosomal structures participate in genome regulation.
N6-methyladenosine (m6A) is the most common internal modification of eukaryotic messenger RNA (mRNA) and is decoded by YTH domain proteins. The mammalian mRNA m6A methylosome is a complex of nuclear proteins that includes METTL3 (methyltransferase-like 3), METTL14, WTAP (Wilms tumour 1-associated protein) and KIAA1429. Drosophila has corresponding homologues named Ime4 and KAR4 (Inducer of meiosis 4 and Karyogamy protein 4), and Female-lethal (2)d (Fl(2)d) and Virilizer (Vir). In Drosophila, fl(2)d and vir are required for sex-dependent regulation of alternative splicing of the sex determination factor Sex lethal (Sxl). However, the functions of m6A in introns in the regulation of alternative splicing remain uncertain. Here we show that m6A is absent in the mRNA of Drosophila lacking Ime4. In contrast to mouse and plant knockout models, Drosophila Ime4-null mutants remain viable, though flightless, and show a sex bias towards maleness. This is because m6A is required for female-specific alternative splicing of Sxl, which determines female physiognomy, but also translationally represses male-specific lethal 2 (msl-2) to prevent dosage compensation in females. We further show that the m6A reader protein YT521-B decodes m6A in the sex-specifically spliced intron of Sxl, as its absence phenocopies Ime4 mutants. Loss of m6A also affects alternative splicing of additional genes, predominantly in the 5′ untranslated region, and has global effects on the expression of metabolic genes. The requirement of m6A and its reader YT521-B for female-specific Sxl alternative splicing reveals that this hitherto enigmatic mRNA modification constitutes an ancient and specific mechanism to adjust levels of gene expression.