Research articles

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  • Nuclei with equal neutron (N) and proton (Z) numbers show enhanced correlations that have been predicted to favour an unusual type of pairing, distinct from normal nuclear superfluidity. Here, technically challenging observations are reported of excited states in the N = Z = 46 nucleus 92Pd, from which evidence is inferred for a type of spin-aligned structure in the ground and low-lying excited states, not established in nuclei before and differing from previous predictions.

    • B. Cederwall
    • F. Ghazi Moradi
    • S. Williams
  • The unusual capability of solid crystalline materials to deform plastically (known as superplasticity) has been found in metals and even ceramics; however, no experimental studies have yet to demonstrate this behaviour in geological materials. It is now demonstrated that some synthetic rocks, which are good analogues for Earth's mantle, undergo homogeneous elongation up to 500% under subsolidus conditions. Calculations show that such superplastic flow in the mantle is inevitably accompanied by significant grain growth that can change fine-grained rocks to coarse-grained aggregates, resulting in increasing mantle viscosity and finally termination of superplastic flow.

    • Takehiko Hiraga
    • Tomonori Miyazaki
    • Hidehiro Yoshida
  • The initial crystal structure of LeuT, together with subsequent functional and structural studies, provided direct evidence for a single, high-affinity substrate-binding site. Recent binding, flux and molecular simulation studies, however, have been interpreted in terms of a model where there are two high-affinity binding sites: the second (S2) site is believed to be located within the extracellular vestibule. Here, direct measurement is performed of substrate binding to wild-type LeuT and to S2 site mutants using isothermal titration calorimetry, equilibrium dialysis and scintillation proximity assays. The conclusion is made that LeuT harbours a single, centrally located, high-affinity substrate-binding site.

    • Chayne L. Piscitelli
    • Harini Krishnamurthy
    • Eric Gouaux
  • Motion of electrons can influence their spins through a fundamental effect called the spin–orbit interaction. Here, a spin–orbit quantum bit (qubit) is implemented in an indium arsenide nanowire, which should offer significant advantages for quantum computing. The spin–orbit qubit is electrically controllable, and information can be stored in the spin. Moreover, nanowires can serve as one dimensional templates for scalable qubit registers, and are suited for both electronic and optical devices.

    • S. Nadj-Perge
    • S. M. Frolov
    • L. P. Kouwenhoven
  • As part of the modENCODE initiative, which aims to characterize functional DNA elements in D. melanogaster and C. elegans, this study uses RNA-Seq, tiling microarrays and cDNA sequencing to explore the transcriptome in 30 distinct developmental stages of the fruitfly. Among the results are scores of new genes, coding and non-coding transcripts, as well as splicing and editing events.

    • Brenton R. Graveley
    • Angela N. Brooks
    • Susan E. Celniker
  • As part of the modENCODE initiative, which aims to characterize functional DNA elements in D. melanogaster and C. elegans, this study presents a genome-wide chromatin landscape of the fruitfly, based on 18 histone modifications. Nine prevalent chromatin states are described. Integrating these analyses with other data types reveals individual characteristics of different genomic elements. The work provides a resource of unprecedented scale for future experimental investigations.

    • Peter V. Kharchenko
    • Artyom A. Alekseyenko
    • Peter J. Park
  • Impulsive behaviour characterizes several psychiatric diseases and violent behaviour but its origins are complex. Here, exon sequencing focused on fourteen serotonin- and dopamine-related genes identified a mutation in HTR2B, which was associated with psychiatric diseases marked by impulsivity in a Finnish population. The role of this serotonin receptor in impulsivity is further supported by the knockout mouse phenotype.

    • Laura Bevilacqua
    • Stéphane Doly
    • David Goldman
  • Place cells in the hippocampus track an animal's position as it travels through space. Previous work contends that sequential place cell maps are produced upon the initial navigation of a new area and subsequently consolidated at rest or during sleep. Here, place-cell firing patterns during rest or sleep are observed before a novel spatial experience, a phenomenon termed 'preplay'. These sequences were separate from the replay of pervious experience and suggest that internal dynamics during rest may organize cell assemblies to be ready for any novel encoding that may occur in the immediate future.

    • George Dragoi
    • Susumu Tonegawa
  • The enzyme eNOS is crucial for regulating vascular function as it can produce both the vasodilator nitric oxide and the vasoconstrictor superoxide. Here it is shown that a modification associated with oxidant stress, S-glutathionylation, switches the enzyme from forming nitric oxide to forming superoxide. In hypertensive vessels, S-glutathionylation of eNOS is increased and this is associated with impaired endothelium-dependent vasodilation.

    • Chun-An Chen
    • Tse-Yao Wang
    • Jay L. Zweier
  • Using DNA from a finger bone, the genome of an archaic hominin from southern Siberia has been sequenced to about 1.9-fold coverage. The group to which this individual belonged shares a common origin with Neanderthals, and although it was not involved in the putative gene flow from Neanderthals into Eurasians, it contributed 4–6% of its genetic material to the genomes of present-day Melanesians. A tooth whose mitochondrial genome is very similar to that of the finger bone further suggests that these hominins are evolutionarily distinct from Neanderthals and modern humans.

    • David Reich
    • Richard E. Green
    • Svante Pääbo
    Article Open Access
  • Ubiquitination of histone H2A has been implicated in polycomb-mediated transcriptional silencing, but its precise functions are unclear. Here, ZRF1 is shown to be recruited to ubiquitinated H2A and to function in displacing polycomb-repressive complex 1 (PRC1) from chromatin to facilitate transcriptional activation.

    • Holger Richly
    • Luciana Rocha-Viegas
    • Luciano Di Croce
  • To investigate the core engine of the eukaryotic mitotic cycle, a minimal control network has been generated in fission yeast that efficiently sustains cellular reproduction. Orderly progression through the major events of the cell cycle is driven by oscillation of an engineered minimal CDK module lacking much of the canonical regulation.

    • Damien Coudreuse
    • Paul Nurse
  • During periods of fasting the liver produces ketone bodies, which the peripheral tissues can use as a source of energy. Here it is shown that fasting inhibits multi-component mTOR complex 1 (mTORC1) in the liver. Inhibition of mTORC1 is required for activation of PPARα, a master regulator that switches on genes involved in ketogenesis. Livers from aged mice have increased mTORC1 signalling, reduced PPARα activity, and reduced ketone production. The observation that mTORC1 promotes an ageing phenotype in the liver fits well with the observation that inhibition of this pathway increases lifespan in several organisms.

    • Shomit Sengupta
    • Timothy R. Peterson
    • David M. Sabatini
  • The histone variant mH2A is shown to be expressed at reduced levels in many melanomas. Loss of mH2A promotes tumour growth and metastasis via transcriptional upregulation of CDK8, a known oncogene. This study therefore reveals a new tumour suppression mechanism exerted by epigenetic modifications.

    • Avnish Kapoor
    • Matthew S. Goldberg
    • Emily Bernstein
  • This study finds frequent mutations in MYD88 in the activated B-cell-like subtype of diffuse large B-cell lymphoma and, with lower frequency, in mucosa-associated lymphoid tissue lymphomas. MYD88 mediates signalling by Toll-like receptors, and the mutations, most of which affect the same amino acid, are shown to activate the pathway and promote cancer cell survival.

    • Vu N. Ngo
    • Ryan M. Young
    • Louis M. Staudt
  • To shed light on the natural history of Precambrian life, the evolutionary history of almost 4,000 gene families across the three domains of life are mapped onto a geological timeline. Over one-quarter of modern gene families arose during a period of rapid diversification of bacterial lineages. Functionally, these genes are likely to be involved in electron transport and respiratory pathways, whereas those that arose later are implicated in functions consistent with an increasingly oxygenating biosphere.

    • Lawrence A. David
    • Eric J. Alm
  • In the retina, highly selective wiring from inhibitory cells contributes to determine the direction-selection characteristics of an individual ganglion cell, yet how the asymmetric wiring inherent to these connections is established was unknown. Here, two independent studies using complementary techniques, including pharmacology, electrophysiology and optogenetics, find that although inhibitory inputs to both sides of the direction-selective cell are uniform early in development, by the second postnatal week, inhibitory synapses on the null side strengthen whereas those on the preferred side remain constant. These plasticity changes occur independent of neural activity, indicating that a specific developmental program is executed to produce the direction-selective circuitry in the retina.

    • Keisuke Yonehara
    • Kamill Balint
    • Botond Roska
    • D. L. Theobald
    Brief Communications Arising