Volume 547 Issue 7662



News Features

How poverty affects the brain p.150

An unprecedented study in Bangladesh could reveal how malnutrition, poor sanitation and other challenges make their mark on child development.

doi: 10.1038/547150a

News & Views

Sensing past the quantum limit p.164

Quantum physics ultimately constrains how well sensors of position, speed and acceleration can perform. A hybrid quantum system that avoids these constraints could give rise to improved sensor technologies. See Letter p.191

doi: 10.1038/547164a

Precision T-cell therapy targets tumours p.165

The T cells of the immune system can destroy tumours, but their activation can be inefficient. Vaccines that exploit tumour mutations elicit robust T-cell responses to tumours, with potential clinical benefits. See Letters p.217 & p.222

doi: 10.1038/nature23093

Arctic plants take up mercury vapour p.167

Trace elements are enriched in plants by natural processes, human activities or both. An analysis of mercury in Arctic tundra vegetation offers fresh insight into the uptake of trace metals from the atmosphere by plants. See Letter p.201

doi: 10.1038/547167a

A liquid reservoir for silent chromatin p.168

The protein HP1 mediates compaction of DNA into a repressive structure called heterochromatin. Analysis reveals that HP1 has liquid-like properties, offering a fresh perspective on genome organization. See Letters p.236 & p.241

doi: 10.1038/nature23089

Taming tangled tau p.170

The protein tau forms abnormal filamentous aggregates called tangles in the brains of people with neurodegeneration. Structures of two such filaments offer pathways to a deeper understanding of Alzheimer's disease. See Article p.185

doi: 10.1038/nature23094

Bile ducts regenerated p.171

The development of a protocol for isolating and expanding the cell population that lines bile ducts has enabled the in vitro generation of bioengineered ducts. These can replace native bile ducts when transplanted into mice.

doi: 10.1038/547171a



The pyrite-type high-pressure form of FeOOH p.205

The pyrite-type high-pressure form of FeOOH is predicted from first principles, and found experimentally to be stable under the conditions at the base of the mantle, with implications for transport of water within Earth’s deep interior.

doi: 10.1038/nature22823

Liquid droplet formation by HP1α suggests a role for phase separation in heterochromatin p.236

Gene silencing by heterochromatin is proposed to occur in part as a result of the ability of heterochromatin protein 1 (HP1) proteins to spread across large regions of the genome, compact the underlying chromatin and recruit diverse ligands. Here we identify a new property of the human HP1α protein: the ability to form phase-separated droplets. While unmodified HP1α is soluble, either phosphorylation of its N-terminal extension or DNA binding promotes the formation of phase-separated droplets. Phosphorylation-driven phase separation can be promoted or reversed by specific HP1α ligands. Known components of heterochromatin such as nucleosomes and DNA preferentially partition into the HP1α droplets, but molecules such as the transcription factor TFIIB show no preference. Using a single-molecule DNA curtain assay, we find that both unmodified and phosphorylated HP1α induce rapid compaction of DNA strands into puncta, although with different characteristics. We show by direct protein delivery into mammalian cells that an HP1α mutant incapable of phase separation in vitro forms smaller and fewer nuclear puncta than phosphorylated HP1α. These findings suggest that heterochromatin-mediated gene silencing may occur in part through sequestration of compacted chromatin in phase-separated HP1 droplets, which are dissolved or formed by specific ligands on the basis of nuclear context.

doi: 10.1038/nature22822

Phase separation drives heterochromatin domain formation p.241

HP1a can nucleate into foci that display liquid properties during the early stages of heterochromatin domain formation in Drosophila embryos, suggesting that the repressive action of heterochromatin may be mediated in part by emergent properties of phase separation.

doi: 10.1038/nature22989