| | Plant biology: Seeing the wood and the trees
The identification of the gene regulatory network that controls the formation of xylem — the major component of wood — opens up new avenues for manipulating plant biomass. | Cell division: Hold on and let go
The discovery and functional analysis of the protein MEIKIN in mice leads to an evolutionarily conserved model of how chromosome segregation is regulated during a specialized type of cell division called meiosis I. | Meikin is a conserved regulator of meiosis-I-specific kinetochore function
The long elusive mammalian meiosis-specific kinetochore factor has been identified in mice; MEIKIN—which plays an equivalent role to the yeast proteins Spo13 and Moa1—ensures mono-orientation, protects sister chromatid cohesion and recruits the kinase PLK1 to the kinetochores. | An Arabidopsis gene regulatory network for secondary cell wall synthesis
The full complement of transcriptional regulators that affect synthesis of the plant secondary cell wall remains largely undetermined; here, the network of protein–DNA interactions controlling secondary cell wall synthesis of Arabidopsis thaliana is determined, showing that gene expression is regulated by a series of feed-forward loops to ensure that the secondary cell wall is deposited at the right time and in the right place. | CetZ tubulin-like proteins control archaeal cell shape
The structure and function of CetZ, a protein related to both tubulin and FtsZ (the bacterial homologue of tubulin) from the archaeon Haloferax volcanii, is reported and its involvement in the control of cell shape uncovered; it appears that this family of proteins was involved in the control of cell shape long before the evolution of eukaryotes. | Dissecting neural differentiation regulatory networks through epigenetic footprinting
The integrative analysis of epigenetic footprints along consecutive stages of neural progenitors derived from human ES cells reveals regulatory mechanisms that orchestrate stage-specific differentiation. | Folding of an intrinsically disordered protein by phosphorylation as a regulatory switch
The structural polymorphism of intrinsically disordered protein 4E-BP2 allows it to regulate translation initiation through post-translational modification-mediated folding, exemplifying a new and potentially general mechanism of biological regulation mediated by intrinsically disordered proteins. | NAD captureSeq indicates NAD as a bacterial cap for a subset of regulatory RNAs
A newly developed method, NAD captureSeq, has been used to show that bacteria cap the 5′-ends of some RNAs to protect against degradation, much as happens with eukaryotic messenger RNAs, although with a different modification: nicotinamide adenine dinucleotide. | Mechanosensory interactions drive collective behaviour in Drosophila
Collective behaviour in animal groups can improve individual perception and decision-making, but the neural mechanisms involved have been hard to access in classic models for these phenomena; here it is shown that Drosophila’s olfactory responses are enhanced in groups of flies, through mechanosensory neuron-dependent touch interactions. | A human tRNA synthetase is a potent PARP1-activating effector target for resveratrol
A human tRNA synthetase connects resveratrol to stress signalling. | Crystal structure of the human OX2 orexin receptor bound to the insomnia drug suvorexant
The orexin system regulates sleep and arousal in humans, with orexin receptor antagonists becoming promising therapeutics for insomnia; now, the X-ray crystal structure of the human OX2 receptor in the presence of the insomnia drug suvorexant is solved. | Lineage-negative progenitors mobilize to regenerate lung epithelium after major injury
Lineage-tracing experiments identify a rare, undifferentiated population of quiescent cells in the mouse distal lung that are activated through a Notch signalling pathway to repair the epithelium after bleomycin- or influenza-mediated injury; inappropriate Notch signalling may be a major contributor to failed regeneration within the lungs of patients with chronic lung disease. | Group 2 innate lymphoid cells promote beiging of white adipose tissue and limit obesity
Group 2 innate lymphoid cells are shown to have a critical role in energy homeostasis by producing methionine-enkephalin peptides in response to interleukin 33, thus promoting the beiging of white adipose tissue; increased numbers of beige (also known as brown-like or brite) fat cells in white adipose tissue leads to increased energy expenditure and decreased adiposity. | Large-scale discovery of novel genetic causes of developmental disorders
Up to half of children with severe developmental disorders of probable genetic origin remain without a genetic diagnosis; here, in a systematic and nationwide study of 1,133 children with severe, undiagnosed developmental disorders, and their parents, exome sequencing and array-based detection of chromosomal rearrangements reveals novel genes causing developmental disorders, increasing the proportion of children that can now be diagnosed to 31%. | | Structure of a mammalian ryanodine receptor
Using electron cryomicroscopy, the closed-state structure of rabbit RyR1 is determined at 4.8 Å resolution; analysis confirms that the RyR1 architecture consists of a six-transmembrane ion channel with a cytosolic α-solenoid scaffold, and suggests a mechanism for Ca2+-induced channel opening.
Ran Zalk, Oliver B. Clarke, Amédée des Georges et al. | Structure of the rabbit ryanodine receptor RyR1 at near-atomic resolution
Using electron cryomicroscopy, the structure of the closed-state rabbit ryanodine receptor RyR1 in complex with its modulator FKBP12 is solved at 3.8 Å; in addition to determining structural details of the ion-conducting channel domain, three previously uncharacterized domains help to reveal a molecular scaffold that allows long-range allosteric regulation of channel activities.
Zhen Yan, Xiao-chen Bai, Chuangye Yan et al. | RNA regulons in Hox 5′ UTRs confer ribosome specificity to gene regulation
Specialized ribosomes (with a particular protein composition) carry out translation of specific transcripts; analysis of Hox mRNA translation in mice reveals that unique RNA structural elements within their 5′ UTRs, including internal ribosome entry sites and translation inhibitory elements, are responsible for this specialized mode of translation.
Shifeng Xue, Siqi Tian, Kotaro Fujii et al. | Architecture and conformational switch mechanism of the ryanodine receptor
Using electron cryomicroscopy, the structure of the rabbit RyR1 calcium channel is determined at 6.1 Å resolution in the closed state and 8.5 Å in the open state, revealing how calcium binding to the EF-hand of RyR1 regulates channel opening and facilitates calcium-induced calcium release.
Rouslan G. Efremov, Alexander Leitner, Ruedi Aebersold et al. | | A higher-than-predicted measurement of iron opacity at solar interior temperatures
Laboratory measurements of iron opacity made under conditions similar to those inside the Sun reveal much higher opacity than predicted, helping to resolve inconsistencies within stellar models of the internal temperatures of stars.
J. E. Bailey, T. Nagayama, G. P. Loisel et al. | Identification of multipotent mammary stem cells by protein C receptor expression
Using transplantation and lineage-tracing strategies, protein C receptor is identified as a marker of mammary stem cells in mice, with potential implications for understanding the initiation of breast cancer.
Daisong Wang, Cheguo Cai, Xiaobing Dong et al. | Higher-than-predicted saltation threshold wind speeds on Titan
Wind tunnel experiments designed to simulate the conditions on Saturn’s moon Titan yield threshold wind speeds for particle saltation higher than those predicted by models derived from simulations of terrestrial-planet conditions; the results can be reconciled by modifying the models to take into account the low ratio of particle density to fluid density on Titan.
Devon M. Burr, Nathan T. Bridges, John R. Marshall et al. | Observation of quantized conductance in neutral matter
Quantized conductance in the transport of neutral atoms is observed in an optically produced channel — either a quantum point contact or a quantum wire — between two atom reservoirs; the lowest non-zero conductance value is the universal conductance quantum, the reciprocal of Planck’s constant.
Sebastian Krinner, David Stadler, Dominik Husmann et al. | An anisotropic hydrogel with electrostatic repulsion between cofacially aligned nanosheets
Usually materials design focuses on attractive interactions, but here a hydrogel is described whose properties are dominated by electrostatic repulsion between negatively charged titanate nanosheets embedded within it; the material, inspired by articular cartilage, deforms easily when sheared parallel to the sheets but resists compressive forces applied orthogonally.
Mingjie Liu, Yasuhiro Ishida, Yasuo Ebina et al. | Strong and deep Atlantic meridional overturning circulation during the last glacial cycle
Reconstruction of the Atlantic meridional overturning circulation from a highly resolved marine sedimentary record shows that a deep, vigorous overturning circulation mode has persisted for most of the last glacial cycle, dominating ocean circulation in the Atlantic, but that a shallower glacial mode prevailed during glacial maxima.
E. Böhm, J. Lippold, M. Gutjahr et al. | Origins of major archaeal clades correspond to gene acquisitions from bacteria
A comparison of protein-coding genes from 134 archaeal genomes with their homologues in 1,847 bacterial genomes reveals that, during evolution, genes are transferred more often from bacteria to archaea than vice versa, and that gene influxes from bacteria can bring about the origin of major archaeal groups.
Shijulal Nelson-Sathi, Filipa L. Sousa, Mayo Roettger et al. | Hepatitis A virus and the origins of picornaviruses
Hepatitis A virus is a picornavirus that causes significant morbidity but remains poorly understood; this paper now provides high-resolution crystal structures of both the mature and the empty hepatitis A virus particle, which show that the three-dimensional structure resembles insect picorna-like viruses.
Xiangxi Wang, Jingshan Ren, Qiang Gao et al. | Human intracellular ISG15 prevents interferon-α/β over-amplification and auto-inflammation
ISG15 deficiency in humans leads to a failure to maintain adequate levels of USP18, triggering an increase in type I interferon production and signalling, and promoting auto-inflammatory disease.
Xianqin Zhang, Dusan Bogunovic, Béatrice Payelle-Brogard et al. | A PP1–PP2A phosphatase relay controls mitotic progression
The activation and coordination of phosphatase activity is important during mitotic exit; here, a mitotic phosphatase relay is described in fission yeast between the two major phosphatases, PP1 and PP2A, a mode of regulation that may be a feature of signalling networks across eukaryotes.
Agnes Grallert, Elvan Boke, Anja Hagting et al. | Native structure of photosystem II at 1.95 Å resolution viewed by femtosecond X-ray pulses
The radiation-damage-free structure of the photosystem II membrane protein complex, which oxidizes water into dioxygen in an oxygen evolving complex, has been determined by an X-ray free electron laser at a resolution of 1.95 Å; one of the substrate oxygen atoms in this reaction is now identified.
Michihiro Suga, Fusamichi Akita, Kunio Hirata et al. | Structure of an integral membrane sterol reductase from Methylomicrobium alcaliphilum
Solving the X-ray crystal structure of a Δ14-sterol reductase and homologue of human C14SR and DHCR7, two enzymes that reduce specific carbon–carbon double bonds in the cholesterol biosynthetic pathway, may provide insight into how specific mutations in DHCR7 and lamin B receptor lead to human diseases.
Xiaochun Li, Rita Roberti, Günter Blobel | | | | |
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