This press release contains:
---Summaries of newsworthy papers:
Planetary science: Planets orbiting pairs of Sun-like stars
Astrophysics: Constraining the nature of a type Ia supernova
Comment: Put a price on whales to save them
Metabolism: A new hormone with exercise-related health benefits
Genomics: Genome sequencing provides clues about AML relapse
Cancer: Novel retinoblastoma therapy
Nature and Nature Medicine: Uncovering the genetic landscape of a leukaemia subtype
Geoscience: Modelling mineral flow under the Earth's mantle
And finally… Stellar companions
---Mention of papers to be published at the same time with the same embargo
---Geographical listing of authors
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[1] Planetary science: Planets orbiting pairs of Sun-like stars (AOP; N&V)
DOI: 10.1038/nature10768
The discovery of two so-called circumbinary planets, which orbit gravitationally bound pairs of stars (binaries), is reported in this week’s Nature. Most Sun-like stars in the Galaxy reside in binaries. This finding adds to previous discoveries of such planets and may help to estimate the fraction of binaries that possess circumbinary planets.
The existence of circumbinary planets orbiting a pair of normal stars was established with the discovery of the Kepler-16 binary system, although the prevalence of such planets has been unclear. From a sample of 750 systems monitored by the Kepler spacecraft, William Welsh and colleagues find two circumbinary planets, Kepler-34 b and Kepler-35 b, both of which are gas giants. By extrapolating the observed rate of circumbinary planets, the authors estimate that around one per cent of close binary stars have nearby giant planets with closely aligned orbits. This calculation implies a Galactic population of at least several million circumbinary planets.
Kepler-34 b orbits two Sun-like stars every 289 days; its mass is 22 per cent of Jupiter’s (the largest gas giant in our Solar System) and its radius is 76 per cent of Jupiter’s. Kepler-35 b is a planet with 13 per cent of the mass and 73 per cent of the radius of Jupiter that orbits a pair of smaller stars every 131 days.
CONTACT
William Welsh (San Diego State University, CA, USA)
Tel: +1 619 594 2288; E-mail: [email protected]
John Southworth (Keele University, Newcastle-under-Lyme, UK) N&V author
E-mail: [email protected]
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[2] Astrophysics: Constraining the nature of a type Ia supernova (pp 164-166; N&V)
The identity of the progenitor of a type Ia supernova in a nearby galaxy is determined in Nature this week. Interpretations of observations of the supernova remnant SNR 0509−67.5 from the Hubble Space Telescope rule out the presence of a companion star. Instead, the findings suggest that the explosion occurred when two white dwarfs merged.
Type Ia supernova explosions are thought to be triggered either by the merger of two white dwarfs (a ‘double-degenerate’ origin) or by a companion star ‘feeding’ the exploding star (the ‘single-degenerate’ model). Bradley Schaefer and Ashley Pagnotta attempt to resolve the identity of the progenitor system by considering SNR 0509–67.5, which is the remnant of a supernova that occurred around 400 years ago in the Large Magellanic Cloud. They report that the central region of the supernova remnant contains no ex-companion star within three times the maximum distance a companion could have been 'kicked' by the explosion.
These results rule out all published single-degenerate models for this supernova, the authors conclude.
CONTACT
Bradley Schaefer (Louisiana State University, Baton Rouge, LA, USA)
Tel: +1 225 578 0015; E-mail: [email protected]
Pilar Ruiz-Lapuente (University of Barcelona, Spain) N&V author
Tel: +34 934 039 235; E-mail: [email protected]
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Comment: Put a price on whales to save them (pp 139-140)
Despite bans on whaling, the number of whales killed has more than doubled since the early 1990s. So far, pro- and anti-whaling groups have failed to reach an agreement that satisfies both sides. In 2010, anti-whaling nations proposed a compromise position that would have established quotas for sanctioned whaling, while reducing total whale takes. But, after much wrangling, that deal fell through. Anti-whaling protest groups continue to put pressure on whaling nations — in early 2011 the groups managed to get Japan to hold off whaling in the Southern Ocean temporarily, but the hunt began again by the end of the year.
In a Comment in Nature this week, Christopher Costello, Leah Gerber and Steven Gaines propose what they hope would be a more permanent and effective solution: a whale market. “By placing an appropriate price tag on the life of a whale, a whale conservation market provides an immediate and tangible way to save them,” the authors say.
Their idea is to create ‘whaling quotas’ that could be bought and sold. The number of whales hunted would depend on who owned the ‘shares’. At one extreme (where whalers purchase all shares), whales would be harvested to the agreed sustainable level. At the other extreme (where conservationists purchase all shares), all whales would be protected from harvest and whalers would be suitably compensated. Such a market has the potential to make all parties better off, and simultaneously improve whale conservation, the authors say.
They calculate that per-whale profit for whalers currently ranges from about US$13,000 for a minke whale to $85,000 for a fin whale. These are figures that are within reach of conservation groups and even some individuals. Non-profit organizations spend a total of at least $25 million a year on anti-whaling, the authors estimate. The Sea Shepherd Conservation Society, for example, estimates that its multimillion-dollar 2008 campaign saved about 350 minke whales in Antarctic waters; those whales could have been ‘purchased’ in a whale market for less than $4 million.
CONTACT
Christopher Costello (University of California, Santa Barbara, CA, USA)
Tel: +1 805 893 5802; E-mail: [email protected]
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[3] Metabolism: A new hormone with exercise-related health benefits (AOP)
DOI: 10.1038/nature10777
Beneficial health effects exerted by a newly identified hormone that is elevated in the blood of humans and mice during exercise are described in this week’s Nature. Enhanced levels of the hormone irisin increases energy expenditure in mice and improves obesity and glucose homeostasis. Thus, irisin may have potential as a therapeutic agent for disorders that are normally improved with exercise.
Some of the best-recognized effects of exercise on muscle are mediated by a protein called PGC1-alpha. Bruce Spiegelman and colleagues show that expression of PGC1-alpha in mouse muscle stimulates the expression of a protein called FNDC5 that is cleaved and secreted as irisin. They demonstrate that irisin is responsible for some the effects of exercise on browning of white fat, which increases energy expenditure and improves resistance to obesity-linked insulin resistance. Relatively short treatments of obese mice with irisin improve glucose homeostasis and cause a small amount of weight loss, which the authors suggest highlights the therapeutic potential of irisin.
CONTACT
Bruce Spiegelman (Harvard Medical School and Dana-Farber Cancer Institute, Boston, MA, USA)
Tel: +1 617 632 3567; E-mail: [email protected]
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[4] Genomics: Genome sequencing provides clues about AML relapse (AOP)
DOI: 10.1038/nature10738
The genome sequencing of patients with acute myeloid leukaemia (AML) before and after relapse is reported in Nature this week. The work reveals patterns of genetic changes associated with relapse and indicates that tumour evolution may, in part, be shaped by chemotherapy.
Most patients with AML die from progressive disease after relapse. Clonal evolution of tumour cell populations after relapse has been observed at the chromosome (cytogenetic) level. To investigate the mutations associated with AML relapse at the genome level, Timothy Ley and colleagues sequenced AML genomes of eight patients. Their study uncovers two major patterns of clonal evolution during relapse: gain of mutations in the founding clone of the primary tumour, and gain of mutations in a subclone of the founder that survives treatment, leading to relapse.
All eight patients received cytotoxic chemotherapy that failed to eradicate the founding clone, and the authors propose that eradication of the founding clone and subclones is key to achieving a cure. Moreover, the authors infer that although chemotherapy is required to induce initial remissions, cytotoxic agents probably contribute to relapse by damaging DNA and generating new mutations.
CONTACT
Timothy Ley (Washington University, St. Louis, MO, USA)
Tel: +1 314 362 8831; E-mail: [email protected]
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[5] Cancer: Novel retinoblastoma therapy (AOP)
DOI: 10.1038/nature10733
Novel targets for the treatment of retinoblastoma — an aggressive childhood cancer — are reported in Nature this week. Integration of whole-genome sequence analysis of genetic and epigenetic features of retinoblastoma provides important insights into the mechanisms behind tumour progression and identifies a potential therapeutic approach.
Retinoblastoma is a rare childhood cancer of the retina caused by loss of a gene called RB1. Michael Dyer and colleagues performed whole-genome sequencing of four retinoblastomas to identify mutations associated with RB1 loss, and found the overall mutation rate to be very low. Although the retinoblastoma genome is stable, multiple cancer pathways turned out to be epigenetically deregulated (that is, modifications to gene expression arise without changing the DNA sequence itself). In particular, they discover that expression of the proto-oncogene SYK is upregulated in retinoblastoma and is required for tumour cell survival; furthermore, they show that a small-molecule inhibitor of the SYK protein can induce retinoblastoma tumour cell death.
These findings go against previous hypotheses suggesting that loss of RB1 causes genomic instability, and thus rules out genetic instability as a driver of rapid tumour progression observed in retinoblastomas. The study underscores the importance of integrating analysis of the genetic and epigenetic features in cancer genomics.
CONTACT
Michael Dyer (St Jude Children’s Research Hospital, Memphis, TN, USA)
Tel: +1 901 595 2257; E-mail: [email protected]
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[6] & [7] Nature and Nature Medicine: Uncovering the genetic landscape of a leukaemia subtype (pp 157-163 & DOI: 10.1038/nm.2651)
The genetic bases of two subtypes of the common childhood malignancy acute lymphoblastic leukaemia are probed in Nature and Nature Medicine this week. Sequencing multiple early T-cell precursor acute lymphoblastic leukaemia (ETP ALL) genomes reveals a range of novel genetic alterations that underlie this disease. A second paper uses comparative genomic hybridization to detect alterations in T-cell acute lymphoblastic leukaemia (T-ALL). These findings provide a platform for selecting potential treatment strategies for both subtypes of the disease.
ETP ALL is an aggressive malignancy and is associated with a high risk of treatment failure. To gain insights into the genetic basis of this disease, Charles Mullighan and colleagues perform whole-genome sequencing in 12 patients with ETP ALL. The pattern of mutations identified in this analysis is similar to that seen in myeloid malignancies. From these results, published in Nature, the authors infer that therapies used for the treatment of myeloid malignancies, such as acute myeloid leukaemia, might be effective in ETP ALL.
Using comparative genomics, Iannis Aifantis and colleagues show in Nature Medicine that genetic alterations in T-ALL diminish the activity of proteins that regulate gene expression by modulating the structure of chromatin. The alterations also overlap with the already well studied Notch signaling pathway and suggest new insights into how Notch promotes tumour growth by altering epigenetic regulation.
CONTACT
Charles Mullighan (St Jude Children’s Research Hospital, Memphis, TN, USA) Author paper [6]
Tel: +1 901 595 3387; E-mail: [email protected]
Iannis Aifantis (New York University, NY, USA) Author paper [7]
Tel: +1 212 263 5365; E-mail: [email protected]
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[8] Geoscience: Modelling mineral flow under the Earth's mantle (pp 177-180; N&V)
Computational modelling of mineral formation under the extreme conditions of the Earth's mantle is presented in Nature this week. These findings may change our understanding of mineral rheology (or flow), which is affected by structure, and the effects of temperature, strain rates and pressure in the mantle.
Difficulties in reproducing the extreme deformation conditions of the mantle and the massive timescales involved have hampered laboratory-based investigations of how minerals form in the Earth. Patrick Cordier and colleagues use multiscale numerical modelling, based on calculations and simulations of strain, pressure and temperature, to assess the rheology of magnesium oxide (MgO). Their results demonstrate that extremely low strain rates counteract the influence of pressure, which means that MgO is a very weak phase in the mantle. The pressure effect only dominates in the lowermost mantle where the mineral becomes highly viscous.
The authors note that the understanding of MgO deformation mechanisms and rheology uncovered here may not be enough to define the rheology of the mantle. However, they postulate that larger-scale modelling may provide a better model of lower mantle dynamics.
CONTACT
Patrick Cordier (Université Lille 1, Villeneuve d’Ascq, France)
Tel: +33 3 20 43 43 41; E-mail: [email protected]
Andrew Walker (University of Bristol, UK) N&V author
E-mail: [email protected]
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[9] And finally… Stellar companions (pp 167-169)
An analysis of extrasolar planets (exoplanets) indicates that, on average, every star in the Milky Way has at least one companion planet. These findings are reported in Nature this week, and suggest that the existence of planets orbiting stars in our Galaxy is the rule, rather than the exception.
Exoplanet detection methods biased towards planets that are relatively close to their parent stars infer that around 17–30 per cent of solar-like stars host a planet. To probe planets that are further away from their stars, Arnaud Cassan and colleagues perform an analysis of data gathered from another planet-detecting technique ― gravitational microlensing.
Their assessment uncovers the fraction of star-bound planets orbiting at a distance of 0.5 to 10 times the Sun–Earth distance. Around 17 per cent of stars host Jupiter-mass planets, around 52 per cent accommodate Neptune-like planets, and ‘super-Earths’ are the most abundant, being associated with around 62 per cent of stars.
CONTACT
Arnaud Cassan (Institut d’Astrophysique de Paris, France)
Tel: +33 1 44 32 80 87; E-mail: [email protected]
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ADVANCE ONLINE PUBLICATION
[10] Complete subunit architecture of the proteasome regulatory particle
DOI: 10.1038/nature10774
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GEOGRAPHICAL LISTING OF AUTHORS…
The following list of places refers to the whereabouts of authors on the papers numbered in this release. For example, London: 4 - this means that on paper number four, there will be at least one author affiliated to an institute or company in London. The listing may be for an author's main affiliation, or for a place where they are working temporarily. Please see the PDF of the paper for full details.
AUSTRALIA
Adelaide: 6
Hobart: 9
Perth: 9
AUSTRIA
Vienna: 9
BELGIUM
Leuven: 1, 6, 7
CANADA
Toronto: 6
CHILE
Concepción: 9
Santiago: 9
CROATIA
Rijeka: 9
DENMARK
Copenhagen: 1, 9
Odense: 3
FRANCE
Fontenay-aux-Roses: 7
Paris: 9
Toulouse: 9
Villeneuve d’Ascq: 8
GERMANY
Garching: 9
Heidelberg: 9
ISRAEL
Haifa: 7
Tel Aviv: 1
ITALY
Ancona: 3
Padua: 6
JAPAN
Osaka: 9
NEW ZEALAND
Christchurch: 9
POLAND
Warszawa: 9
SINGAPORE
Singapore: 6
SOUTH AFRICA
Observatory: 9
SPAIN
Alicante: 7
UNITED KINGDOM
Cambridge: 9
London: 9
St Andrews: 9
UNITED STATES OF AMERICA
California
Belmont: 3
Berkeley: 1, 10
Livermore: 9
Moffett Field: 1
Mountain View: 1
Pasadena: 1, 9
San Diego: 1
San Francisco: 3, 6
San Jose: 1
Santa Barbara: 1
Santa Cruz: 1
Sonoma: 1
Colorado
Aurora: 6
Florida
Gainesville: 1, 6
Georgia
Atlanta: 1
Illinois
Batavia: 1
Indiana
Notre Dame: 9
Louisiana
Baton Rouge: 2
Massachusetts
Boston: 3
Cambridge: 1
Charlestown: 5
Maryland
Baltimore: 1, 9
Chevy Chase: 5
Missouri
St Louis: 4, 5, 6
New Mexico
Albuquerque: 6
New York
Bronx: 7
New York: 6, 7
Yorktown Heights: 7
Pennsylvania
Philadelphia: 6
Villanova: 1
Tennessee
Memphis: 5, 6
Texas
Austin: 1
Virginia
Charlottesville: 6
Washington
Seattle: 6
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PRESS CONTACTS…
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From Japan, Korea, China, Singapore and Taiwan
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Tel: +81 3 3267 8751; E-mail: [email protected]
From the UK
Rebecca Walton, Nature, London
Tel: +44 20 7843 4502; E-mail: [email protected]
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