Editors' Choice

Science  05 May 2017:
Vol. 356, Issue 6337, pp. 498
  1. Neurodevelopment

    RPE cranks it up a Notch

    1. Megan Eldred

    Notch signaling influences cell fate during mammalian eye development.

    PHOTO: SCIENCE SOURCE

    Notch signaling within and between cells is involved in many processes, including cell fate specification. In the retina, high levels of Notch during retinal progenitor cell (RPC) division promote RPC renewal, whereas low levels promote postmitotic neuron differentiation. Ha et al. found that retinal pigment epithelium (RPE), a neighboring tissue to the neural retina, influences asymmetric division by localizing Notch components to the apical side of the adjacent dividing RPC. This positioning required an E3 ubiquitin protein ligase, Mib1, which boosts levels of Notch in one sister cell, but not the other. Hence, a neighboring tissue influenced cell-fate specification through Notch signaling, which could also happen in other neural tissues.

    Cell Rep. 10.1016/j.celrep.2017.03.040 (2017).

  2. Cell Biology

    Not making the right contacts

    1. Stella M. Hurtley

    The microtubule-severing enzyme spastin is mutated in the inherited neural disease, or axonopathy, called hereditary spastic paraplegia (HSP). The endoplasmic reticulum (ER) within cells, including neurons, plays a role in defining the position and timing of endosomal tubule fission. Allison et al. identified a role for spastin at ER-endosome contact sites during endosomal tubule fission. Failure of this process caused problems in lysosomal enzyme trafficking. Lysosomal abnormalities developed in primary cortical neurons from a spastin-HSP mouse model, human stem cell–derived neurons from a spastin-HSP patient, and neurons from mice lacking the ER-shaping protein REEP1. All of these neurons developed pathological axonal swellings associated with accumulations of abnormal lysosomes. Failure to correctly manage lysosome biogenesis may play a role in multiple HSPs and possibly other neurodegenerative conditions.

    J. Cell Biol. 10.1083/jcb201609033 (2017).

  3. Neuroscience

    The three-dimensional world in the brain

    1. Peter Stern

    We live and navigate easily in a complex three-dimensional world. However, little is known how this three-dimensional space and our movements within it are represented in the human brain. Kim et al. scanned participants while they were performing a virtual navigation task. Behaviorally, subjects had similarly accurate memory for vertical and horizontal locations. For a direction judgment task, vertical tilt facilitated performance. A brain region called the right anterior hippocampus contains place information that is sensitive to both horizontal and vertical axes. Vertical directional information, however, is represented in the right posterior hippocampus in an area called the retrosplenial cortex.

    J. Neurosci. 37, 4270 (2017).

  4. Nanomaterials

    Short chains for a smart film

    1. Phil Szuromi

    Polymer films capable of changing their structural properties at the nanoscale in response to physiological temperature changes could have a number of biological applications. To achieve periodic structures with feature sizes below 10 nm, an amphiphilic polymer must join highly immiscible polymer blocks with short chains. Nowak et al. synthesized an amphiphile that joined a disaccharide and a polypropylene oligomer with a triazole linkage. Spin-cast ultrathin films of this material formed “fingerprint” lamellar domains of the blocks that were perpendicular to the surface with a spacing of ∼6 nm at room temperature. However, heating to 38°C for 72 hours led to a nanostructure in which the chains were stacked parallel to the surface in head-tail bilayers.

    J. Am. Chem. Soc. 10.1021/jacs.6b13285 (2017).

  5. Plant Science

    Competing inputs and shifting outcomes build shape

    1. Pamela J. Hines

    Asymmetric cell division creates leaf shapes by mechanical and chemical signals.

    PHOTO: KAIS TOLMATS/GETTY IMAGES

    Asymmetric cell division contributes to the development of shape in growing organisms. Bringmann and Bergmann distinguish mechanical from signaling effects as cell division planes are deployed in the developing Arabidopsis leaf. Computational growth models reveal that dividing cells are influenced by both. Early in leaf development, as the midvein is rapidly elongating, mechanical stress dominates. Later in leaf development, as the epidermis enlarges and growth of the midvein slows, local ligand-receptor signaling dominates. The balance of inputs shifts through development, and the final shape of the leaf emerges.

    Curr. Biol. 27, 877 (2017).

  6. Diversity in Science

    Committees, candidates, and gender

    1. Brad Wible

    Quotas to increase female representation on academic evaluation committees may unexpectedly hamper efforts to narrow gender gaps in the professoriate. Bagues et al. studied large-scale national evaluation programs for hiring and promotion in Italy and Spain, which use committees drawn randomly from pools of experts. Although female committee members show no greater statistical preference than males for female candidates, female presence on committees leads male committee members to be less favorable toward female candidates. Higher proportions of women on committees do not increase the number of female candidates promoted, nor do they lead to better identification of candidates who ultimately prove to be more productive.

    Amer. Econ. Rev. 107, 1207 (2017).

  7. Applied Optics

    Miniaturizing optical gyroscopes

    1. Ian S. Osborne

    Gyroscopes are used in many applications and can be found in devices such as position sensors, inertial navigation systems, and motion stabilizers. Science museum toys consisting of spinning wheels and gimbals illustrate the general principle of operation, but decades of research have focused on their miniaturization and developing alternative operating systems. Optical systems based on the interference of counter-propagating laser beams can be extremely sensitive and robust, but they tend to use bulky components. Liang et al. and Li et al. have developed optical microresonator–based gyroscopes that can fit onto an optical chip. With demonstrated performance better than that of existing microphotonic systems, such components offer the possibility of building more lightweight, robust, and sensitive gyroscopes.

    Optica 4, 114, 346 (2017).

Navigate This Article