Table of Contents

Volume 517 Number 7533 pp121-236

8 January 2015

About the cover

After injury to the nervous system in the nematode Caenorhabditis elegans, an axon sprouts new growth towards its detached segment; a membrane-tethered fluorophore is shown in blue, and the cytoplasm magenta. Fragments are slightly repositioned for clarity. Massimo Hilliard and colleagues provide a detailed analysis of a highly efficient means of regeneration in the C. elegans nervous system known as axonal fusion, in which separated axon segments are able to spontaneously reconnect and fuse to restore the original circuitry. Fusion in this context prevents the breakdown of the detached axon segment and requires regeneration only to bridge the region of damage. The authors investigate the molecular machinery required for this regenerative process, and find that it begins with changes to the phospholipid composition of the axonal membrane followed by recruitment of specific molecules in the regrowing axon as well as from surrounding tissues. Remarkably, the molecules and mechanisms discovered in this process mirror those involved in the recognition and engulfment of apoptotic cells by phagocytes. Cover design by Nick Valmas, image by Casey Linton.

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    Career Briefs


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    • Three-dimensional head-direction coding in the bat brain

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      • Dori Derdikman
      • Alon Rubin
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      • Liora Las
      • Nachum Ulanovsky

      A study of freely moving bats provides new insights into how the brain encodes a three-dimensional neural compass; neurons were identified encoding the three Euler rotation angles of the head (azimuth, pitch, and roll) and recordings from these head-direction cells revealed a toroidal model of spatial orientation mapped out by cells tuned to two circular variables (azimuth × pitch).

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      • Fiona Cuskin
      • Elisabeth C. Lowe
      • Max J. Temple
      • Yanping Zhu
      • Elizabeth A. Cameron
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      • Nathan T. Porter
      • Karthik Urs
      • Andrew J. Thompson
      • Alan Cartmell
      • Artur Rogowski
      • Brian S. Hamilton
      • Rui Chen
      • Thomas J. Tolbert
      • Kathleen Piens
      • Debby Bracke
      • Wouter Vervecken
      • Zalihe Hakki
      • Gaetano Speciale
      • Jose L. Munōz-Munōz
      • Andrew Day
      • Maria J. Peña
      • Richard McLean
      • Michael D. Suits
      • Alisdair B. Boraston
      • Todd Atherly
      • Cherie J. Ziemer
      • Spencer J. Williams
      • Gideon J. Davies
      • D. Wade Abbott
      • Eric C. Martens
      • Harry J. Gilbert

      Mannan, a component of yeast cell walls, is shown to be a viable food source for Bacteroides thetaiotamicron, a dominant member of the gut microbiota, which catabolizes the mannan ‘selfishly’—countering the general assumption that multiple members of the gut microbiota take a role in, and benefit from, polysaccharide catabolism.

    • Glutathione activates virulence gene expression of an intracellular pathogen

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      • Aaron T. Whiteley
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      • Daniel A. Portnoy

      This study shows that glutathione, a ubiquitous antioxidant, is also a critical signalling molecule that allosterically activates the master virulence regulator in the intracellular pathogen Listeria monocytogenes.


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      • Andrew Hooper
      • Sigrún Hreinsdóttir
      • Kristín S. Vogfjörd
      • Benedikt G. Ófeigsson
      • Elías Rafn Heimisson
      • Stéphanie Dumont
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      • Karsten Spaans
      • Gunnar B. Gudmundsson
      • Vincent Drouin
      • Thóra Árnadóttir
      • Kristín Jónsdóttir
      • Magnús T. Gudmundsson
      • Thórdís Högnadóttir
      • Hildur María Fridriksdóttir
      • Martin Hensch
      • Páll Einarsson
      • Eyjólfur Magnússon
      • Sergey Samsonov
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      • Robert S. White
      • Thorbjörg Ágústsdóttir
      • Tim Greenfield
      • Robert G. Green
      • Ásta Rut Hjartardóttir
      • Rikke Pedersen
      • Richard A. Bennett
      • Halldór Geirsson
      • Peter C. La Femina
      • Helgi Björnsson
      • Finnur Pálsson
      • Erik Sturkell
      • Christopher J. Bean
      • Martin Möllhoff
      • Aoife K. Braiden
      • Eva P. S. Eibl

      Seismicity and ground deformation measurements show how a recent segmented dyke intrusion in the Bárðarbunga volcanic system in Iceland grew laterally for 45 kilometres over 14 days; dyke opening and seismicity were focused at the most distal segment, where lateral dyke growth with segment barrier breaking by pressure build-up occurred.

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      • John A. Long
      • Elga Mark-Kurik
      • Zerina Johanson
      • Michael S. Y. Lee
      • Gavin C. Young
      • Zhu Min
      • Per E. Ahlberg
      • Michael Newman
      • Roger Jones
      • Jan den Blaauwen
      • Brian Choo
      • Kate Trinajstic

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      • Richard R. Stein
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      • Asia Gobourne
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      • Melissa Kinnebrew
      • Agnes Viale
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    • EFF-1-mediated regenerative axonal fusion requires components of the apoptotic pathway

      • Brent Neumann
      • Sean Coakley
      • Rosina Giordano-Santini
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      • Eui Seung Lee
      • Akihisa Nakagawa
      • Ding Xue
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      Unlike the limited post-injury neuronal regeneration in humans, severed axons in C. elegans can regenerate through a cellular fusion mechanism; this study identifies the molecular basis for this process which includes phosphatidylserine recognition and a role for specific molecules that also act in apoptosis.

    • Allosteric activation of the RNF146 ubiquitin ligase by a poly(ADP-ribosyl)ation signal

      • Paul A. DaRosa
      • Zhizhi Wang
      • Xiaomo Jiang
      • Jonathan N. Pruneda
      • Feng Cong
      • Rachel E. Klevit
      • Wenqing Xu

      Structural and biochemical approaches are used to show how RNF146 activity is allosterically regulated by the binding of poly(ADP-ribose) ligand, and how substrate specificity is achieved with protein poly(ADP-ribosyl)ation and ubiquitination occurring in the same protein complex.

    • The heat released during catalytic turnover enhances the diffusion of an enzyme

      • Clement Riedel
      • Ronen Gabizon
      • Christian A. M. Wilson
      • Kambiz Hamadani
      • Konstantinos Tsekouras
      • Susan Marqusee
      • Steve Pressé
      • Carlos Bustamante

      It has been traditionally assumed that the heat released during a single enzymatic catalytic event does not perturb the enzyme in any way; however, here single-molecule fluorescence correlation spectroscopy is used to show that, for enzymes that catalyse chemical reactions with large reaction enthalpies, the heat released at the protein's active site during catalysis transiently displaces the protein's centre-of-mass, essentially giving rise to a recoil effect that propels the enzyme.

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