Nature contents: 12 September 2013

Can't view this email? Click here to view in your browser.     Volume 501 Number 7466      nature •Visit Nature homepage •Subscribe to Nature •View Table of Contents The science that matters. Every week.               Research opportunities in Brazil  Conferences with FAPESP representatives at the Naturejobs Career Expo 2013, in London, will showcase opportunities in different fields Brazil to begin clinical trials for an oral vaccine against hepatitis B  Sign up for FAPESP's free weekly newsletter with the latest developments of Brazilian science       Jump to the content that matters to you View Table of Contents ▶ ▼ News & Comment   ▼ Biological Sciences   ▼ Chemical Sciences   ▼ Physical Sciences   ▼ Earth & Environmental Sciences   ▼ Careers & Jobs       This week's highlights     Biological Sciences More Biological sciences ▼   Social reward requires coordinated activity of nucleus accumbens oxytocin and serotonin   Social behaviours, such as co-operation, favour group survival, but often at a cost to the individual. Reinforcement is needed if these behaviours are to persist. This study shows that oxytocin acts as a social reinforcement signal in the nucleus accumbens core in mice, where together with serotonin alters the transmission of signals along neurons. This provides a possible mechanism for encoding social reinforcement, and offers targets for further study of the neural mechanisms of social dysfunction.       Physical Sciences More Physical sciences ▼   Stimulated X-ray emission for materials science   X-ray scattering and X-ray emission spectroscopy are powerful techniques for exploring the fundamental electronic and vibrational excitations of materials. However, to get measurable signals, targets often need to be blasted with an intense X-ray beam that may damage the sample. This problem can be circumvented with X-ray free-electron lasers. Using silicon as an example, Martin Beye and colleagues show that such lasers can induce stimulated X-ray emission from a solid sample to provide a superior probe for low energy excitations and their dispersion in matter. Stimulated X-ray emission has previously been demonstrated in gas, but its realization in a solid should open up a host of new possibilities.       Earth & Environmental Sciences More Earth & Environmental sciences ▼   Non-chondritic sulphur isotope composition of the terrestrial mantle   The differentiation of early Earth's subsurface material into core and mantle is reflected in the residual mantle composition, since most of the iron-loving elements, including presumably sulphur, would have been scavenged by the liquid core. However, previous analyses of Earth's mantle have identified stable sulphur isotope ratios resembling of chondritic meteorites, perhaps the result of a 'late veneer' meteoritic origin for mantle material. Jabrane Labidi et al. provide evidence that the mantle displays heterogeneous sulphur isotope ratios directly correlated to strontium and neodymium isotope ratios. These observations have implications for our understanding of sulphur cycling and the origin of certain elements found in Earth's mantle.           A*STAR Research - Highlighting the best of research at the Agency for Science, Technology and Research (A*STAR), Singapore's premier research organization Recent Highlights Solar energy: A richer harvest on the horizon | Immunology: White blood cells show their stripes   The new print edition of A*STAR Research is now available!            Podcast & Video     This week, turning adult cells into stem cells in living mice, retracing the footsteps of a controversial frog-hunter, and what does Stephen Hawking's new memoir reveal about the man? Plus, the best science from outside Nature.         News & Comment Read daily news coverage▶ ▲top               THIS WEEK           Editorials                   Sequenced from the start ▶     Four US studies are set to explore how genomic data can best help healthy and ill newborns. They must also settle some questions of ethics.             Under threat ▶     The grey wolf is at risk of losing its endangered status under US law.             Reality at risk ▶     Don’t treat a memoir as anything other than one person’s interpretation of events.             World View                   It is time to update US biomedical funding ▶     The effects of federal budget cuts provide an opportunity to revisit the funding structure of the National Institutes of Health, says Frederick Grinnell.             Seven Days     nbsp;             Seven days: 6–12 September 2013 ▶     The week in science:             NEWS IN FOCUS           Grey wolves left out in the cold ▶     US plan to remove federal protection elicits howls of protest.             Physicists net fractal butterfly ▶     Decades-old search closes in on recursive pattern that describes electron behaviour.             Hackles rise over privatization plan ▶     UK Natural Environment Research Council proposes to cut four institutes loose, but scientists fear for long-term data.             Secrets of fracking fluids pave way for cleaner recipe ▶     Disclosure of chemicals used in hydraulic fracturing will empower green chemistry.             More cuts loom for US science ▶     Stalemate in Congress puts spending plans on hold.             Ultimate upgrade for US synchrotron ▶     Argonne lab banks on beam-bending magnets in bid for world’s most focused X-ray light source.             Features                   Taxonomy: The spy who loved frogs ▶     To track the fate of threatened species, a young scientist must follow the jungle path of a herpetologist who led a secret double life.             Physics: Quantum quest ▶     Physicists have spent a century puzzling over the paradoxes of quantum theory. Now a few of them are trying to reinvent it.             COMMENT           Policy: A single market for European research ▶     European collaboration is not far behind that in the United States, but there is still work to be done on cross-border funding and financial inequalities, says Paul Boyle.             Research: A standard for policy-relevant science ▶     Ian Boyd calls for an auditing process to help policy-makers to navigate research bias.             Health care: Bring on the evidence ▶     It is time to probe whether the trend for patient and public involvement in medical research is beneficial, say Sophie Petit-Zeman and Louise Locock.             Books and Arts                   Physics: A cosmological life ▶     Robert P. Crease weighs up two takes on Stephen Hawking — including the theoretical physicist's own.             Biology: Evolution of a mind ▶     Eugenie C. Scott revels in the first volume of Richard Dawkins's frank new memoir.             Sociology of science: Chasing the gravitational wave ▶     Marianne de Laet enjoys a sociological analysis of how a select group of physicists works.             Psychology: Mapping memory's lanes ▶     Alison Abbott sees the science and poetry in a penetrating study of reminiscence in the elderly.             Correspondence                   Politics: Turkey's scientists can't ignore politics Ozan Aygün | Neuroscience: Transcranial devices are not playthings Marom Bikson, Sven Bestmann, Dylan Edwards | Data sharing: Don't compromise on informed consent Helen Wallace | Genomics: HeLa genome versus donor's genome Henry H. Heng | Biology: A forgotten history of sex research Andrea C. Gore             Obituary                   Anthony James Pawson (1952–2013) ▶     Biochemist whose vision of cell signalling transformed cancer research.             Correction                   Correction ▶                     Biological Sciences ▲top             RESEARCH           Latest Online                   Stem cells: Down's syndrome link to ageing ▶     George P. Souroullas, Norman E. Sharpless             Stem cells: Reprogramming in situ ▶     Alejandro De Los Angeles, George Q. Daley             Usp16 contributes to somatic stem-cell defects in Down’s syndrome ▶     Maddalena Adorno, Shaheen Sikandar, Siddhartha S. Mitra et al.     An analysis of somatic tissues derived from mouse models of Down’s syndrome shows reduced self-renewal capacities in various cell types, with these defects partially dependent on triplication of the Usp16 gene; overexpression and knockout studies in human cells shows that USP16 has a role in Down’s syndrome-related proliferation defects, making this gene an attractive option for further study.             Reprogramming in vivo produces teratomas and iPS cells with totipotency features ▶     María Abad, Lluc Mosteiro, Cristina Pantoja et al.     Induced pluripotent stem cells (iPS cells) have been created in vivo by reprogramming mouse somatic cells with Oct4, Sox2, Klf4 and c-Myc; these cells have totipotent features that are missing from in vitro created iPS cells or embryonic stem cells.             Uhrf1-dependent H3K23 ubiquitylation couples maintenance DNA methylation and replication ▶     Atsuya Nishiyama, Luna Yamaguchi, Jafar Sharif et al.     The RING finger domain protein Uhrf1 is known to have an important role in DNA methylation pattern maintenance through the recruitment of the methyltransferase Dnmt1 to hemimethylated DNA sites: here, Uhrf1 is shown to act as a ubiquitin ligase for H3, an essential step in Dnmt1 recruitment.             Two replication fork maintenance pathways fuse inverted repeats to rearrange chromosomes ▶     Lingchuan Hu, Tae Moon Kim, Mi Young Son et al.     Stalling of replication forks in sequences that have non-allelic repeats can lead to genomic rearrangements; here two pathways consistent with homologous recombination and error-free post-replication repair fuse identical and mismatched repeats, respectively, thus inducing chromosomal rearrangements in mouse embryonic stem cells.             Cyclin A regulates kinetochore microtubules to promote faithful chromosome segregation ▶     Lilian Kabeche, Duane A. Compton     Cyclin A is shown to maintain unstable kinetochore–microtubule (k–MT) attachments in prometaphase in order to allow for error correction; at the prometaphase–metaphase switch, k-MT attachments are stabilized when cyclin A drops below threshold levels.             Immune clearance of highly pathogenic SIV infection ▶     Scott G. Hansen, Michael Piatak Jr, Abigail B. Ventura et al.     Cellular immune responses in rhesus macaques (Macaca mulatta) vaccinated with cytomegalovirus vectors expressing SIV proteins are able to stringently control highly pathogenic SIV infection, regardless of the route of challenge, after systemic spread; immunological and virological analyses of protected macaques followed for up to 3 years suggest that persistent immune surveillance by vaccine-elicited immune responses may have cleared the infection.             The maize Gα gene COMPACT PLANT2 functions in CLAVATA signalling to control shoot meristem size ▶     Peter Bommert, Byoung Il Je, Alexander Goldshmidt et al.     The maize COMPACT PLANT2 locus encodes a Gα subunit; its interaction with leucine-rich receptors suggests a new mode of G-protein signalling that acts through single-pass rather than seven-pass G-protein-coupled transmembrane receptors.             Migrating bubble during break-induced replication drives conservative DNA synthesis ▶     Natalie Saini, Sreejith Ramakrishnan, Rajula Elango et al.     This paper demonstrates that the mechanism of break-induced replication (BIR) is significantly different from S-phase replication, as it proceeds via a migrating bubble driven by Pif1 helicase, results in conservative inheritance of newly synthesized DNA, and is inherently mutagenic.             Pif1 helicase and Polδ promote recombination-coupled DNA synthesis via bubble migration ▶     Marenda A. Wilson, YoungHo Kwon, Yuanyuan Xu et al.     This paper demonstrates that Pif1 helicase works with polymerase d to promote DNA synthesis through a migrating D-loop, a mechanism used to copy tens of kilobases during repair of chromosome breaks by break-induced replication (BIR).             Articles and Letters                   Social reward requires coordinated activity of nucleus accumbens oxytocin and serotonin ▶     Gül Dölen, Ayeh Darvishzadeh, Kee Wui Huang et al.     In male mice oxytocin acts as a social reinforcement signal within the nucleus accumbens (NAc) core, where it elicits a presynaptically expressed long-term depression (LTD) of excitatory synaptic transmission in medium spiny neurons; deletion of oxytocin receptors from the dorsal raphe nucleus, which provides serotonergic innervation of the NAc, and blockade of NAc serotonin 1B receptors both prevent oxytocin-induced LTD and social reward.             RNAi screens in mice identify physiological regulators of oncogenic growth ▶     Slobodan Beronja, Peter Janki, Evan Heller et al.     Here, the first genome-wide in vivo RNA interference screens in a mammalian animal model are reported: genes involved in normal and abnormal epithelial cell growth are studied in developing skin tissue in mouse embryos, and among the findings, β-catenin is shown to act as an antagonist to normal epithelial cell growth as well as promoting oncogene-driven growth.             Computational design of ligand-binding proteins with high affinity and selectivity ▶     Christine E. Tinberg, Sagar D. Khare, Jiayi Dou et al.     Computational protein design is used to create a protein that binds the steroid digoxigenin (DIG) with high affinity and selectivity; the computational design methods described here should help to enable the development of a new generation of small molecule receptors for synthetic biology, diagnostics and therapeutics.             De novo mutations in epileptic encephalopathies ▶     Exome sequencing has found an excess of de novo mutations in the ∼4,000 most intolerant genes in patients with two classical epileptic encephalopathies (infantile spasms and Lennox–Gastaut syndrome); among them are multiple de novo mutations in GABRB3 and ALG13.             Induction of mouse germ-cell fate by transcription factors in vitro  ▶     Fumio Nakaki, Katsuhiko Hayashi, Hiroshi Ohta et al.     Expression of the three transcription factors BLIMP1, PRDM14 and TFAP2C, or of PRDM14 alone, converts epiblast-like cells into primordial germ cell (PGC)-like cells; the transcription-factor-induced PGC-like cells acquire key transcriptome and epigenetic reprogramming in PGCs, and contribute to spermatogenesis and fertile offspring.             The pluripotent genome in three dimensions is shaped around pluripotency factors ▶     Elzo de Wit, Britta A. M. Bouwman, Yun Zhu et al.     Using 4C technology, higher-order topological features of the pluripotent genome are identified; in pluripotent stem cells, Nanog clusters specifically with other pluripotency genes and this clustering is centred around Nanog-binding sites, suggesting that Nanog helps to shape the three-dimensional structure of the pluripotent genome and thereby contributes to the robustness of the pluripotent state.             Mechanism of MEK inhibition determines efficacy in mutant KRAS- versus BRAF-driven cancers ▶     Georgia Hatzivassiliou, Jacob R. Haling, Huifen Chen et al.     The mechanism of action of three different allosteric MEK inhibitors that target the MAP kinase pathway is investigated, and their efficacy is shown to be explained by the distinct mechanisms regulating MEK activation in KRAS- versus BRAF-driven tumours; this work provides a rationale for designing more effective cancer therapies for these common genetic subtypes of cancer.             Completion of the entire hepatitis C virus life cycle in genetically humanized mice ▶     Marcus Dorner, Joshua A. Horwitz, Bridget M. Donovan et al.     The entire hepatitis C virus life cycle can be recapitulated in an inbred mouse model, allowing preclinical assessment of antiviral therapeutics and vaccines.             Pathogen blocks host death receptor signalling by arginine GlcNAcylation of death domains ▶     Shan Li, Li Zhang, Qing Yao et al.     Several death-domain-containing proteins are directly inactivated by the enteropathogenic Escherichia coli type III secretion system effector NleB; NleB functions as an N-acetylglucosamine transferase that modifies a conserved death domain arginine residue, blocking the receptor–adapter interaction.             A type III effector antagonizes death receptor signalling during bacterial gut infection ▶     Jaclyn S. Pearson, Cristina Giogha, Sze Ying Ong et al.     Colonizing enteric bacteria are shown to inhibit the antimicrobial process of host cell apoptosis through the action of NleB1, a type III secretion system effector with N-acetylglucosamine transferase activity, which can bind and modify eukaryotic death-domain-containing proteins.             Stability and function of regulatory T cells is maintained by a neuropilin-1–semaphorin-4a axis ▶     Greg M. Delgoffe, Seng-Ryong Woo, Meghan E. Turnis et al.     Neuropilin-1 (Nrp1) on regulatory T (Treg) cells is shown to interact with semaphorin-4a (Sema4a) to promote a program of Treg-cell stability and survival, in part through PTEN-mediated modulation of Akt signalling; Nrp1-deficient Treg cells can maintain immune homeostasis but fail to suppress in inflammatory sites, such as tumours, providing an attractive immunotherapeutic target for the treatment of cancers.             Interactome map uncovers phosphatidylserine transport by oxysterol-binding proteins ▶     Kenji Maeda, Kanchan Anand, Antonella Chiapparino et al.     The lipid-binding profiles of all lipid-transfer proteins in Saccharomyces cerevisiae are determined and a new subfamily of oxysterol-binding proteins that function in phosphatidylserine homeostasis and transport is identified.             News & Views                   Biological techniques: An embryonic view of tumour development ▶     Pawel J. Schweiger & Kim B. Jensen             Immunology: Lipopolysaccharide sensing on the inside ▶     Vijay A. K. Rathinam & Katherine A. Fitzgerald             50 & 100 Years Ago ▶             Computational biology: A recipe for ligand-binding proteins ▶     Giovanna Ghirlanda             Stem cells: Down's syndrome link to ageing ▶     George P. Souroullas, Norman E. Sharpless             Stem cells: Reprogramming in situ ▶     Alejandro De Los Angeles, George Q. Daley             Corrigenda                   Corrigendum: A CRISPR/Cas system mediates bacterial innate immune evasion and virulence ▶     Timothy R. Sampson, Sunil D. Saroj, Anna C. Llewellyn, Yih-Ling Tzeng & David S. Weiss             Corrigendum: X-ray analysis on the nanogram to microgram scale using porous complexes ▶     Yasuhide Inokuma, Shota Yoshioka, Junko Ariyoshi, Tatsuhiko Arai, Yuki Hitora et al.             Retraction                   Retraction: Bird-like fossil footprints from the Late Triassic ▶     Ricardo N. Melchor, Silvina de Valais & Jorge F. Genise             Research Highlights                   Animal behaviour: Clumping caterpillars | Ecology: US forests grow to be different | Language: Babies hear a primate's call | Synthetic biology: Forcing fluorine into molecules | Primate cognition: Monkeys raise the alarm on predators | Cell biology: Nuclear receptor linked to fitness         NEWS & COMMENT           Sequenced from the start | Under threat | Grey wolves left out in the cold | Anthony James Pawson (1952–2013) | Taxonomy: The spy who loved frogs | Health care: Bring on the evidence | Biology: Evolution of a mind | Psychology: Mapping memory's lanes | Neuroscience: Transcranial devices are not playthings | Genomics: HeLa genome versus donor's genome | Biology: A forgotten history of sex research             More Biological Sciences ▶                 nature.com webcasts   Macmillan Science Communication presents a custom webcast on: Prenatal cytogenetics: chromosome microarray analysis as a first tier   September 19th 8am PDT/11am EDT/4pm BST/5pm CEST   Free webcast and live Q & A    Sponsored by: Affymetrix          Chemical Sciences ▲top             RESEARCH           Latest Online                   Efficient planar heterojunction perovskite solar cells by vapour deposition ▶     Mingzhen Liu, Michael B. Johnston, Henry J. Snaith     The use of organometal halide perovskites as the light-absorbing material in nanostructured solar cells has increased efficiency to practical levels; here it is shown that vapour deposition of the perovskite removes the need for complex nanostructures and will hence simplify large-scale manufacture.             Articles and Letters                   Stereoinversion of tertiary alcohols to tertiary-alkyl isonitriles and amines ▶     Sergey V. Pronin, Christopher A. Reiher, Ryan A. Shenvi     Tertiary alcohols are displaced with a nitrogen nucleophile with stereoinversion and with high selectivity over less substituted alcohols, providing complementarity to the SN2 reaction and efficient access to nitrogenous marine terpenoids.             News & Views                   Astrochemistry: Extracts of meteorite ▶     Andrew Mitchinson             Research Highlights                   Chemistry: Power from deep-sea vents | Synthetic biology: Forcing fluorine into molecules         NEWS & COMMENT           Secrets of fracking fluids pave way for cleaner recipe             More Chemical Sciences ▶               Physical Sciences ▲top             RESEARCH           Latest Online                   Materials science: Fast-track solar cells ▶     Michael D. McGehee             Efficient planar heterojunction perovskite solar cells by vapour deposition ▶     Mingzhen Liu, Michael B. Johnston, Henry J. Snaith     The use of organometal halide perovskites as the light-absorbing material in nanostructured solar cells has increased efficiency to practical levels; here it is shown that vapour deposition of the perovskite removes the need for complex nanostructures and will hence simplify large-scale manufacture.             Articles and Letters                   Stimulated X-ray emission for materials science ▶     M. Beye, S. Schreck, F. Sorgenfrei et al.     Resonant inelastic X-ray scattering requires very high photon densities to detect the relatively weak signals of interest, but here it is demonstrated that inducing stimulated X-ray emission from crystalline silicon can increase the signal level by several orders of magnitude and reduces sample damage.             Stereoinversion of tertiary alcohols to tertiary-alkyl isonitriles and amines ▶     Sergey V. Pronin, Christopher A. Reiher, Ryan A. Shenvi     Tertiary alcohols are displaced with a nitrogen nucleophile with stereoinversion and with high selectivity over less substituted alcohols, providing complementarity to the SN2 reaction and efficient access to nitrogenous marine terpenoids.             News & Views                   Social science: The mathematics of murder ▶     Adeline Lo, James H. Fowler             Materials science: Boosting X-ray emission ▶     Ernst Fill             Astrochemistry: Extracts of meteorite ▶     Andrew Mitchinson             Materials science: Fast-track solar cells ▶     Michael D. McGehee             Research Highlights                   Chemistry: Power from deep-sea vents | Technology: A cheaper, quieter MRI machine | Synthetic biology: Forcing fluorine into molecules | Physics: A startling value for gravitation         NEWS & COMMENT           Secrets of fracking fluids pave way for cleaner recipe | Physics: Quantum quest | Physics: A cosmological life | Sociology of science: Chasing the gravitational wave | Physicists net fractal butterfly | Ultimate upgrade for US synchrotron             More Physical Sciences ▶               Earth & Environmental Sciences ▲top             RESEARCH           Articles and Letters                   Changes in North Atlantic nitrogen fixation controlled by ocean circulation ▶     Marietta Straub, Daniel M. Sigman, Haojia Ren et al.     Reconstructed changes in North Atlantic nitrogen fixation over the past 160,000 years have a 23,000-year cycle that is interpreted to result from precession-paced changes in the supply of phosphorus to surface waters by equatorial Atlantic upwelling.             Retardation of arsenic transport through a Pleistocene aquifer ▶     Alexander van Geen, Benjamín C. Bostick, Pham Thi Kim Trang et al.     Holocene aquifers are the source of much arsenic poisoning in south and southeast Asia, whereas Pleistocene aquifers are mostly safe; here the delayed arsenic contamination of a Pleistocene aquifer is described and modelled.             Non-chondritic sulphur isotope composition of the terrestrial mantle ▶     J. Labidi, P. Cartigny, M. Moreira     Earth’s mantle is shown to display heterogeneous sulphur isotope ratios, with a depleted end-member that is not chondritic as has been thought; the mantle’s inferred composition can be accounted for by fractionation during core–mantle differentiation.             News & Views                   Geochemistry: Sulphur from heaven and hell ▶     Nicolas Dauphas             50 & 100 Years Ago ▶             Research Highlights                   Chemistry: Power from deep-sea vents | Geology: Meet the world's largest volcano         NEWS & COMMENT           Under threat | Grey wolves left out in the cold | Secrets of fracking fluids pave way for cleaner recipe | Hackles rise over privatization plan             More Earth & Environmental Sciences ▶               Special - Technology Feature ▲top               Next-generation sequencing: The genome jigsaw ▶     Advances in high-throughput sequencing are accelerating genomics research, but crucial gaps in data remain.                 Nature Publishing Group and the weekly Nature podcast are now on Soundcloud! Visit http://bit.ly/14mEZ7R to hear or download the latest episodes and add your comments. 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