Volume 460 Issue 7251, 2 July 2009

A cardiovascular progenitor population from human fetal hearts capable of generating all the main cardiac cell types is described this week by Kenneth Chien and colleagues. Despite glimpses of success, the road to cardiac regenerative medicine is proving a long haul [see News, p. 18]. The cover image, by Paul R. Riley, illustrating a heart wrapped in a layer of regenerating cells, is from a study showing that thymosin β4 guides progenitor cells from the outer layer of the heart to tissue repair sites ().



  • Editorial |

    Iran's endogenous civil-rights movement needs international solidarity, not political meddling. Academics, universities and non-governmental organizations can help.

  • Editorial |

    Carbon dioxide is not the only warming agent worth tackling now in the bid to cool the planet.

Research Highlights

Journal Club


News in Brief


  • Column |

    To call biomedical research proposals political distorts the issue, says David Goldston.

    • David Goldston


  • News Feature |

    Slotting a fusion reactor into the heart of a nuclear fission plant could accelerate the development of waste-free nuclear energy. So why are all the designs still on paper, asks Ed Gerstner.

    • Ed Gerstner
  • News Feature |

    With their focus on greenhouse gases, atmospheric scientists have largely overlooked lowly soot particles. But black carbon is now a hot topic among researchers and politicians. Jeff Tollefson investigates.

    • Jeff Tollefson


Books and Arts

News & Views

  • News & Views |

    How the salamander regrows an entire limb after injury has flummoxed the wisest of scientists. A closer look at the cells involved in limb regeneration shows that remembering past origins may be crucial for this feat.

    • Alejandro Sánchez Alvarado
  • News & Views |

    Levels of atmospheric carbon dioxide constrain vegetation types and thus also non-biological uptake during rock weathering. That's the reasoning used to explain why CO2 levels did not fall below a certain point in the Miocene.

    • Yves Goddéris
    •  & Yannick Donnadieu
  • News & Views |

    Two therapeutic drugs have been found to enhance memory in immune cells called T cells, apparently by altering cellular metabolism. Are changes in T-cell metabolism the key to generating long-lived immune memory?

    • Martin Prlic
    •  & Michael J. Bevan
  • News & Views |

    Photons don't interact well with each other, which is a real headache for researchers developing all-optical transistors for computing applications. But a single molecule can mediate photon–photon affairs.

    • Michel Orrit
  • News & Views |

    Actively dividing cells do so at a risk — with each division, chromosome ends tend to shorten. Pairing proteins that promote cell division with a chromosome-end repair factor is a smart way to solve this problem.

    • Sarah E. Millar
  • News & Views |

    As capacitors, the ubiquitous components of electronic circuitry, get smaller, keeping them insulating is a challenge. But that's not necessarily bad news — some conductivity might be just the thing for data storage.

    • Pavlo Zubko
    •  & Jean-Marc Triscone



  • Article |

    The generation of patient-specific induced pluripotent stem cells (iPS cells) is thought to hold great therapeutic potential. Here, somatic cells from Fanconi anaemia patients are reprogrammed to pluripotency after correction of the genetic defect, generating patient-specific iPS cells.

    • Ángel Raya
    • , Ignasi Rodríguez-Pizà
    • , Guillermo Guenechea
    • , Rita Vassena
    • , Susana Navarro
    • , María José Barrero
    • , Antonella Consiglio
    • , Maria Castellà
    • , Paula Río
    • , Eduard Sleep
    • , Federico González
    • , Gustavo Tiscornia
    • , Elena Garreta
    • , Trond Aasen
    • , Anna Veiga
    • , Inder M. Verma
    • , Jordi Surrallés
    • , Juan Bueren
    •  & Juan Carlos Izpisúa Belmonte
  • Article |

    By using an integrated GFP transgene to track the major limb tissues during limb regeneration in the salamander Ambystoma mexicanum (the axolotl), it has been possible to demonstrate that each limb tissue produces a different set of progenitors with restricted potential. Thus, the blastema—the collection of cells that regenerates the diverse tissues of the limb—is composed of a heterogeneous collection of restricted progenitor cells instead of dedifferentiated pluripotent cells, as previously thought.

    • Martin Kragl
    • , Dunja Knapp
    • , Eugen Nacu
    • , Shahryar Khattak
    • , Malcolm Maden
    • , Hans Henning Epperlein
    •  & Elly M. Tanaka
  • Article |

    The genetic pathways controlling stem cells are frequently dysregulated during tumorigenesis, with either stimulation of Wnt/β-catenin signalling or overexpression of telomerase sufficient to activate epidermal stem cells in vivo. Here, the telomerase protein component TERT (telomerase reverse transcriptase) is shown to have a role as a transcriptional modulator of the Wnt/β-catenin pathway, revealing a significant level of integration between the two pathways.

    • Jae-Il Park
    • , Andrew S. Venteicher
    • , Ji Yeon Hong
    • , Jinkuk Choi
    • , Sohee Jun
    • , Marina Shkreli
    • , Woody Chang
    • , Zhaojing Meng
    • , Peggie Cheung
    • , Hong Ji
    • , Margaret McLaughlin
    • , Timothy D. Veenstra
    • , Roel Nusse
    • , Pierre D. McCrea
    •  & Steven E. Artandi


  • Letter |

    On antigen stimulation, CD8 T cells undergo a developmental program characterized by expansion and then contraction of antigen-specific effector (TE) populations, followed by the persistence of long-lived memory (TM) cells. During this transition, CD8 T cells are now shown to switch from glucose metabolism to fatty acid metabolism by a TRAF6-dependent mechanism.

    • Erika L. Pearce
    • , Matthew C. Walsh
    • , Pedro J. Cejas
    • , Gretchen M. Harms
    • , Hao Shen
    • , Li-San Wang
    • , Russell G. Jones
    •  & Yongwon Choi
  • Letter |

    Inducing effective memory T-cell responses is a major goal of vaccines against chronic infections and tumours. Here, mTOR, the mammalian target for the immunosuppressive drug rapamycin, is shown to enhance the quantity and quality of virus-specific CD8 T cells in mouse and non-human primate models.

    • Koichi Araki
    • , Alexandra P. Turner
    • , Virginia Oliva Shaffer
    • , Shivaprakash Gangappa
    • , Susanne A. Keller
    • , Martin F. Bachmann
    • , Christian P. Larsen
    •  & Rafi Ahmed
  • Letter |

    Studying the mechanisms underlying the diversification of human heart cell lineages has been hampered by the lack of genetic tools to purify early cardiac progenitors and define their developmental potential. By using independent transgenic and gene-targeting approaches in human embryonic stem cell lines, it has now been possible to show that populations of these primordial progenitors are capable of self-renewal and expansion prior to differentiation into the three major cell types in the heart.

    • Lei Bu
    • , Xin Jiang
    • , Silvia Martin-Puig
    • , Leslie Caron
    • , Shenjun Zhu
    • , Ying Shao
    • , Drucilla J. Roberts
    • , Paul L. Huang
    • , Ibrahim J. Domian
    •  & Kenneth R. Chien
  • Letter |

    The Jak–Stat3 pathway is known to mediate leukaemia inhibitory factor (LIF) signals, maintaining pluripotency in mouse embryonic stem cells; however, it is unclear how LIF signals are linked to the core circuitry of pluripotency-associated transcription factors. Here it is shown that two LIF signalling pathways are each connected to the core circuitry by different transcription factors, indicating that there are parallel pathways controlling pluripotency.

    • Hitoshi Niwa
    • , Kazuya Ogawa
    • , Daisuke Shimosato
    •  & Kenjiro Adachi
  • Letter |

    Caspases, and the proximal regulators of caspases, are central to the core machinery of apoptosis. The results of a genome-wide silencing screen in Drosophila—using a strategy combining a library of double-stranded RNAs together with a chemical antagonist of Inhibitor of apoptosis proteins (IAPs)—now reveals a set of validated targets necessary for cell death provoked by several stimuli, as well as a new effector for apoptosis, Tango7.

    • Su Kit Chew
    • , Po Chen
    • , Nichole Link
    • , Kathleen A. Galindo
    • , Kristi Pogue
    •  & John M. Abrams
  • Letter |

    During both stem cell differentiation and X-chromosome inactivation (XCI) of mouse embryonic stem cells, chromatin undergoes epigenetic reprogramming. XCI and cell differentiation are tightly coupled, with the blocking of one process compromising the other. The pluripotency factor, Oct4, is now shown to regulate XCI, and is the first identified factor that links both processes.

    • Mary E. Donohoe
    • , Susana S. Silva
    • , Stefan F. Pinter
    • , Na Xu
    •  & Jeannie T. Lee
  • Letter |

    Ultraluminous X-ray sources are extragalactic objects located outside the nucleus of the host galaxy with bolometric luminosities exceeding 1039 erg s−1. These extreme luminosities imply the presence of an accreting black hole with a mass of 102–105 solar masses, but the existence of such intermediate mass black holes is in dispute. A variable X-ray source with an implied mass of 500 solar masses is now reported in the galaxy ESO 243–49.

    • Sean A. Farrell
    • , Natalie A. Webb
    • , Didier Barret
    • , Olivier Godet
    •  & Joana M. Rodrigues
  • Letter |

    The transistor is the most fundamental building block in present-day technologies. For the purpose of quantum information processing schemes and for the development of a 'quantum computer', photons are attractive information carriers because of their speed and robustness against decoherence. However, their robustness also prevents them from being easily controlled; despite this, experiments now show the realization of a quantum optical transistor.

    • J. Hwang
    • , M. Pototschnig
    • , R. Lettow
    • , G. Zumofen
    • , A. Renn
    • , S. Götzinger
    •  & V. Sandoghdar
  • Letter |

    As alternative technologies for non-volatile memory elements are looked at, the utilization of ferroelectric layers to read-write upon is seen as promising. However, it is plagued by several problems, including a destructive readout process. Now, by using a thin layer of BaTiO3 put under intense strain, it has been shown possible to read out the polarization state of the material without destroying it.

    • V. Garcia
    • , S. Fusil
    • , K. Bouzehouane
    • , S. Enouz-Vedrenne
    • , N. D. Mathur
    • , A. Barthélémy
    •  & M. Bibes
  • Letter |

    It is thought that the Earth's atmospheric carbon dioxide concentrations did not fall below about 200–250 parts per million during the past 24 million years despite the drawdown of atmospheric carbon dioxide by high rates of global silicate rock weathering. Simulations of terrestrial and geochemical carbon cycles now suggest that limited vegetation activity in regions of active mountain ranges effectively diminished biotic-driven silicate rock weathering and thereby provided a negative feedback mechanism to stabilize carbon dioxide concentrations.

    • Mark Pagani
    • , Ken Caldeira
    • , Robert Berner
    •  & David J. Beerling
  • Letter |

    The style of accretion of the lower oceanic crust at mid-ocean ridges is disputed, with some models proposing that the lower oceanic crust is accreted from melt sills intruded at multiple levels within the lower crust. However, seismic images of such sills have been elusive; here, deep crustal seismic reflections off the southern Juan de Fuca ridge are interpreted as originating from a molten sill presently forming within the lower oceanic crust.

    • J. Pablo Canales
    • , Mladen R. Nedimović
    • , Graham M. Kent
    • , Suzanne M. Carbotte
    •  & Robert S. Detrick
  • Letter |

    Human beings are able to rapidly detect the presence of object categories such as animals or vehicles, even when a scene is presented very briefly. The use of functional magnetic resonance imaging during an object categorization task now indicates that the rapid detection of categorical information in natural scenes is mediated by a category-specific biasing mechanism in object-selective cortex that operates across the visual field.

    • Marius V. Peelen
    • , Li Fei-Fei
    •  & Sabine Kastner
  • Letter |

    Mycobacterium tuberculosis induces a cyclic AMP (cAMP) burst within infected macrophages that influences cell signalling, but the underlying mechanism for this increase in cAMP remains unclear. It is now shown that it is produced by a bacterial adenylate cyclase that facilitates delivery of bacterial-derived cAMP into the macrophage cytoplasm, presumably enhancing virulence through the activation of downstream signalling pathways.

    • Nisheeth Agarwal
    • , Gyanu Lamichhane
    • , Radhika Gupta
    • , Scott Nolan
    •  & William R. Bishai



  • Careers Q&A |

    Founding director of the new German Centre for Neurodegenerative Diseases in Bonn, Germany.

  • Postdoc Journal |

    Motherhood has its benefits

    • Joanne Isaac
  • Career Brief |

    Federal legislators worry that US research universities are losing their edge.

  • Career Brief |

    Federal grant sets up neuroplasticity centre at Stanford.

  • Career Brief |

    A green economy will create jobs and battle climate change.

  • Careers and Recruitment |

    Despite the economic downturn, US universities are seeking faculty members with stem-cell expertise. That doesn't mean times are easy. Monya Baker investigates.

    • Monya Baker
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