This press release is copyright Nature.
VOL.463 NO.7283 DATED 18 FEBRUARY 2010
This press release contains:
· Summaries of newsworthy papers:
Oncology: Cancer and copy number
Opinion: Lessons from the Haiti earthquake
Physics: General relativity tested in the lab
Astronomy: Multi-wavelength view of an astrophysical jet
Stem cells: iPS to understand diseases
Astronomy: Supernova progenitors constrained by their X-rays
And finally… Learning to sing changes the brain
· Mention of papers to be published at the same time with the same embargo
· Geographical listing of authors
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 &  Oncology: Cancer and copy number (pp 893-905)
The largest analysis so far of DNA copy-number differences in human cancers suggests that several tumour types share significant genetic features. The find, reported in two papers in this week’s Nature, boosts our understanding of cancer biology.
Human cancer cell DNA commonly includes regions that have been copied one or more times, or deleted. Matthew Meyerson and colleagues show that most of the significant somatic copy-number alterations (SCNAs) within any single cancer type tend to be found in other cancer types as well. Alongside other strands of evidence, this suggests that the apparent diversity seen in cancer genomes may reflect combinations of a limited number of functionally relevant events.
Their work analyses more than 3,000 cancer specimens, belonging largely to 26 histological types. The team highlight 158 SCNAs, most of which do not include known cancer target genes. But they do demonstrate a cancer-causing role for the cell suicide genes MCL1 and BCL2L1 that reside in amplifications found in many cancers.
In a related paper, Michael Stratton and colleagues analyse a large number of homozygous gene deletions in a large collection of cancer cell lines. Combined with information about hemizygous deletions of the same genes, these data suggest that many homozygous deletions found in cancer reflect the position of these genes at fragile sites of the genome, rather than recessive cancer genes the loss of which confers a selective growth advantage.
Matthew Meyerson (Dana-Farber Cancer Institute, Boston, MA, USA) Author paper 
Tel: +1 617 632 4768; E-mail: [email protected]
Michael Stratton (Wellcome Trust Sanger Institute, Cambridge, UK) Author paper 
Tel: +44 1223 494757; E-mail: [email protected]
Opinion: Lessons from the Haiti earthquake (pp 878-879)
In an Opinion piece in Nature this week, Roger Bilham, one of the first seismologists to visit Haiti after last month’s earthquake, calls for United Nations enforcement of earthquake-resistant construction in cities with a history of violent tremors. The projected doubling in world population means that we are constructing more buildings now than at any time in our history, he writes, “in recent earthquakes buildings have acted as weapons of mass destruction”. He argues that “the survival of top-heavy water towers amid areas of pancaked ruins in low-lying areas” illustrates that the disaster need not have been more than twice as lethal as any previous magnitude-7.0 event.
Bilham, who inspected the area around the epicentre in the weeks after 12 January, explains why there is a small chance of there being another earthquake as large, or larger, on the same fault soon. He highlights seismological features of this quake, and others in the region’s past, that must be accounted for during the rebuilding of Port-au-Prince.
Roger Bilham (University of Colorado, Boulder, CO, USA)
Tel: +1 303 492 6189; E-mail: [email protected]
 Physics: General relativity tested in the lab (pp 926-929)
One of the central predictions of Einstein’s theory of general relativity — that a gravitational field slows the running of a clock — has been confirmed to unprecedented accuracy using the results of laboratory experiments performed more than 10 years ago.
The experiments, which were originally used to measure the acceleration of gravity, detected the quantum-mechanical interference of single caesium atoms as they rose and fell in an atomic fountain. Tuned laser pulses placed each atom in a quantum superposition of two trajectories that, because of the wave-like behaviour of quantum particles, created an interference pattern, with a phase difference proportional to the gravitational field.
Holger Müller and colleagues realised that these experiments could be re-interpreted to yield the value of the clock-slowing effect, or ‘gravitational redshift’. In this week’s Nature, they point out that, viewed in the framework of general relativity, each atom is a tiny clock, oscillating at a frequency proportional to its rest-mass energy. Because the two trajectories sampled by each atom attain slightly different heights, their phase difference measures the gravitational redshift.
By comparing the atomic data to the redshift expected from the local value of gravity, measured conventionally, the authors confirm the predicted value of the gravitational redshift to an accuracy of seven parts in a billion — a 10,000-fold improvement on the best previous result.
Holger Müller (University of California, Berkeley, CA, USA)
Tel: +1 510 664 4298; E-mail: [email protected]
 Astronomy: Multi-wavelength view of an astrophysical jet (pp 919-923; N&V)
Observations of an active galaxy made simultaneously at many wavelengths have yielded new insight into the workings of its high-speed, outflowing jet. The results constrain the origin of the strong radiation coming from the galaxy 3C 279, and illustrate the benefits of continuous monitoring of such objects across the electromagnetic spectrum.
Active galaxies such as 3C 279, known as 'blazars', emit strong and variable radiation at all observable wavelengths, arising from a near-light-speed jet pointing very nearly towards the Earth. Details of the emission process, including the location of the emitting region, are poorly known, with estimates for the distance from the galaxy's central black hole ranging from light-hours to light-years.
In this week's Nature, Grzegorz Madejski and colleagues address this question using data from the recently launched Fermi Gamma-Ray Space Telescope, combined with satellite and ground-based observations spanning the spectrum from X-rays to radio waves. During a year-long monitoring effort, the authors caught 3C 279 in the act of emitting a sharp gamma-ray flare, which coincided with a dramatic change in the polarization angle of the object's optical emission. The close association of these events suggests that the gamma-rays and optical emission arise from the same region, and the authors conclude that this region is probably at least one light-year away from the black hole.
Grzegorz Madejski (Stanford University, Menlo Park, CA, USA)
Tel: +1 650 926 5184; E-mail: [email protected]
Andy Young (University of Bristol, UK) N&V author
Tel: +44 117 9288716; E-mail: [email protected]
 Stem cells: iPS to understand diseases (AOP)
*** This paper will be published electronically on Nature's website on 17 February at 1800 London time / 1300 US Eastern time (which is also when the embargo lifts) as part of our AOP (ahead of print) programme. Although we have included it on this release to avoid multiple mailings it will not appear in print on 18 February, but at a later date. ***
The mechanisms underlying a degenerative disease have been studied using induced pluripotent stem (iPS) cells. The work, published online in Nature this week, provides an insight into dyskeratosis congenita (DC), a tissue wasting disorder.
A telomere is a region of DNA which protects the end of the chromosome from deterioration, and in DC the maintenance of telomeres is faulty, resulting in premature cell death. Daley and colleagues use iPS technology to better understand DC and its effect on cells. They show that reprogramming the cells can restore the telomere elongation, and that the cells could overcome a limitation in a component called TERC.
Although the work is preliminary, the authors hope that strategies to increase TERC expression could be therapeutically beneficial in DC patients.
George Daley (Children’s Hospital Boston, MA, USA)
Tel: +1 617 919 2013; E-mail: [email protected]
 Astronomy: Supernova progenitors constrained by their X-rays (pp 924-925)
One of the two favoured explanations for type Ia supernovae cannot be responsible for more than about 5% of these events in elliptical galaxies, according to a paper in this week’s Nature.
Type Ia supernovae are thought to result from thermonuclear explosions of carbon–oxygen white dwarf stars. Two possible processes could lead to such an explosion: either the white dwarf could gradually gain material by accretion from a companion star, or an explosion could be triggered by the merger of two white dwarfs in a compact binary system.
Marat Gilfanov and Ákos Bogdán note that the accretion model would imply copious production of X-rays for about 10 million years before the explosion; by contrast, in the merger model, no strong electromagnetic emission is expected until just before the explosion. Armed with this distinction, the authors examine the X-ray luminosities of five nearby elliptical galaxies, and the bulge of the Andromeda galaxy — all of which have uniform populations of old stars, and only small amounts of obscuring gas and dust.
The observed X-ray emission is 30–50 times less than would be expected if the type Ia supernovae in these regions were originating from accreting white dwarfs, implying that only a very small fraction of the supernovae can be produced by the accretion mechanism.
Marat Gilfanov (Max Planck Institute for Astrophysics, Garching, Germany)
Tel: +49 89 30000 2227; E-mail: [email protected]
 And finally… Learning to sing changes the brain (pp 948-952)
Learning to sing increases synaptic activity and promotes structural changes in the brain, a study of juvenile songbirds suggests. The paper, published in this week’s Nature, helps establish a physical foundation for learning and memory and suggests a putative mechanism by which youngsters learn culturally transmitted behaviours from their peers.
High resolution in vivo imaging revealed structural changes to dendritic spines, tiny neuronal projections that are the sites of synaptic connections. Within 24 hours of learning their first song, the normally dynamic dendritic spines of juvenile zebra finches become larger and more stable. This is accompanied by enhanced synaptic activity, Richard Mooney and colleagues report.
Previous studies have demonstrated a correlation between structural changes in the brain and sensory experience, but whether these same changes accompany learning is uncertain. This study provides a link between learning and changes in brain microanatomy, demonstrating how experience influences the structural and functional properties of synapses to help young birds ‘find their voice’.
Richard Mooney (Duke University, Durham, NC, USA)
Tel: +1 919 684 5025; E-mail: [email protected]
ALSO IN THIS ISSUE…
 Active site remodeling accompanies thioester bond formation in the SUMO E1 (pp 906-912; N&V)
 Variability in gene expression underlies incomplete penetrance (pp 913-918; N&V)
 Upside-down differentiation and generation of a ‘primordial’ lower mantle (pp 930-933)
 Rere controls retinoic acid signalling and somite bilateral symmetry (pp 953-957)
 TCR–peptide–MHC interactions in situ show accelerated kinetics and increased affinity (pp 963-967)
ADVANCE ONLINE PUBLICATION
***These papers will be published electronically on Nature's website on 17 February at 1800 London time / 1300 US Eastern time (which is also when the embargo lifts) as part of our AOP (ahead of print) programme. Although we have included them on this release to avoid multiple mailings they will not appear in print on 18 February, but at a later date. ***
 The primary transcriptome of the major human pathogen Helicobacter pylori
 Remarkably ancient balanced polymorphisms in a multi-locus gene network
 Differential innate immune signalling via Ca2+ sensor protein kinases
 Proviral silencing in embryonic stem cells requires the histone methyltransferase ESET
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.
Gif-sur-Yvette: 4, 15
Berlin: 3, 13
Garching: 4, 6
Monte Porzio Catone: 4
Pino Torinese: 4
Nagoya: 1, 4
Tokyo: 1, 4
Mexico City: 4
St. Petersburg: 4, 6
Barcelona: 1, 4
Cambridge: 2, 4
Berkeley: 3, 4, 10
Big Pine: 4
La Jolla: 12
Moffett Field: 4
Rohnert Park: 4
San Diego: 8
San Francisco: 11
Santa Cruz: 4
Stanford: 4, 12
District of Columbia
Washington: 3, 4
Iowa City: 5
Chevy Chase: 1
College Park: 4
Boston: 1, 4, 5, 15
Cambridge: 1, 4, 8
Ann Arbor: 1, 4, 10
Grand Rapids: 2
Kansas City: 11
St Louis: 14
Santa Fe: 13
New York: 1, 8
Chapel Hill: 1
Philadelphia: 1, 15
University Park: 4
College Station: 15
Seattle: 1, 4
From North America and Canada
Neda Afsarmanesh, Nature New York
Tel: +1 212 726 9231; E-mail: [email protected]
From Japan, Korea, China, Singapore and Taiwan
Mika Nakano, Nature Tokyo
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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