Editors' Choice

Science  10 Feb 2017:
Vol. 355, Issue 6325, pp. 592
  1. Regeneration

    Regrow like an axolotl

    1. Beverly A. Purnell

    Axolotls regenerate limbs by using a mechanism with ancient origins.


    Unlike starfish or fictional superheroes, most vertebrates cannot regrow their limbs. Axolotls are an exception. Owing to the large size of their genomes (32 Gb), Bryant et al. turned to RNA sequencing, de novo transcriptome assembly, and experimental validation to probe regeneration in these salamanders. First, cirbp, a gene encoding an RNA-binding protein, was identified and found to play a role in protecting progenitor cells from cell death. Further, kazald1 was important for temporal and spatial aspects of limb regeneration, similar to prior findings in hydra, suggesting an ancient evolutionary origin. Aspects of limb regeneration share some features with mechanisms of cancer and the wound response; hence, the axolotl data could be a valuable resource.

    Cell Rep. 18, 762 (2017).

  2. Heart Disease

    Interfering with bad cholesterol

    1. Paula A. Kiberstis

    Over the past few decades, the number of deaths from cardiovascular disease has declined substantially in developed countries. Statins, drugs that lower serum levels of low-density lipoprotein cholesterol (LDL-C), have been instrumental in this trend. Not everyone responds to statins, however, and new types of cholesterol-lowering drugs are attracting great interest. Fitzgerald et al. tested inclisiran, a drug based on small interfering RNA technology, in a small phase 1 trial. Inclisiran induces degradation of the mRNA encoding PCSK9, a liver-derived protease whose activity increases serum LDL-C levels. Subcutaneous injection of inclisiran durably reduced PCSK9 levels by as much as 83% and LDL-C levels by as much as 59% without serious toxicities.

    New Engl. J. Med. 376, 41 (2017).

  3. Influenza

    Gluing up hemagglutinin

    1. Caroline Ash

    The morbidity and economic tolls of influenza virus are huge, regardless of its capacity to kill. Vaccines and therapies to control this persistent threat are limited. In structural studies, Kadam and Wilson show how the broad-spectrum antiviral arbidol inactivates viral hemagglutinin (HA). HA is a surface glycoprotein that recognizes the host and mediates virus fusion and disgorgement of nucleic acids into the cell. Arbidol binds in hydrophobic cavities in the upper region of the HA stem, creating a network of interactions that makes the molecule rigid and prevents cell fusion. Resolving the molecular details of the arbidol-HA interactions is essential for the optimization and global deployment of this potential new influenza drug.

    Proc. Natl. Acad. Sci. U.S.A. 114, 206 (2017).

  4. Malnutrition

    Child growth sensitivity to rainfall variability

    1. Caroline Ash

    Child growth in Nepal correlates with the weather and crop productivity.


    Agricultural production and crop diversity are highly sensitive to climate and local weather variables. To assess the sensitivity of child growth and weight gain to precipitation, Shiveley combined data for Uganda and Nepal collected over 30 years from several sources and controlled for multiple covariates. Positive anthropometric outcomes correlate with rainfall before birth, but, in some settings, high and unexpected rainfall can be harmful by damaging harvests or facilitating disease. The impact of increasingly variable weather on faltering agricultural productivity can be buffered by even modest improvements to roads and bridges, thus providing easier access to markets and health facilities.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1524482114 (2017).

  5. Inorganic Chemistry

    Fluorine frolicking with eight friends

    1. Jake Yeston

    Fluorine plays a supporting role in some of the best-known hypervalent compounds, such as PF5 and SF6. Goesten et al. now suggest that the halogen can also play the lead part in constrained environs. Certain zeolites bind fluoride at the center of a box motif with silicons at each of eight vertices. Using density functional theory, the authors report that all eight engage in stabilizing Si-F orbital interactions. Whereas hypervalency is more often associated with third- and fourth-row elements, in this motif, sterics preclude analogous bonding to the heavier halides.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1615742114 (2017).

  6. Education

    Skills to pay the bills?

    1. Melissa McCartney

    Circular and pedagogical reform is often occurring in undergraduate science, technology, engineering, and math (STEM) departments. How can institutions measure whether these curriculum changes are successful? The Survey of Teaching Beliefs and Practices for Undergraduates (STEP-U) developed by Marbach-Ad et al. measures the value that students attribute to skills needed for the workplace (e.g., the ability to work in groups) and teaching practices intended to promote these skills (e.g., group assignments). Specifically, STEP-U is able to simultaneously assess student experiences and teaching practices, ultimately allowing departments to design curricula that better prepare students for the STEM workforce. STEP-U's potential for driving both departmental and institutional change is high, because it can be used to illustrate student experiences between cohorts, within subdisciplines, or between majors.

    CBE Life Sci. Educ. 10.1187/cbe.16-05-0164 (2016).

  7. Ice Sheets

    Cliff driving

    1. H. Jesse Smith

    Iceberg calving from ice sheets contributes roughly as much to sea level rise as mass loss from melting, but the dynamics of calving are not well enough understood to allow precise estimates of how it may change in a warmer future. Ma et al. investigated how stress within the ice controls the balance between tensile and shear failure of marine-terminating glaciers, as a function of water depth. This allowed them to define an ice cliff stability envelope that can be used as boundary conditions in numerical ice sheet models, thereby facilitating better predictions of the magnitude of ice sheet calving.

    Geophys. Res. Lett. 10.1002/2016GL071560 (2017).