TY - JOUR AB - The ability to adapt growth and development to temperature variations is crucial to generate plant varieties resilient to predicted temperature changes. However, the mechanisms underlying plant response to progressive increases in temperature have just started to be elucidated. Here, we report that the Cyclin-dependent Kinase G1 (CDKG1) is a central element in a thermo-sensitive mRNA splicing cascade that transduces changes in ambient temperature into differential expression of the fundamental spliceosome component, ATU2AF65A. CDKG1 is alternatively spliced in a temperature-dependent manner. We found that this process is partly dependent on both the Cyclin-dependent Kinase G2 (CDKG2) and the interacting co-factor CYCLIN L1 resulting in two distinct messenger RNAs. Relative abundance of both CDKG1 transcripts correlates with ambient temperature and possibly with different expression levels of the associated protein isoforms. Both CDKG1 alternative transcripts are necessary to fully complement the expression of ATU2AF65A across the temperature range. Our data support a previously unidentified temperature-dependent mechanism based on the alternative splicing of CDKG1 and regulated by CDKG2 and CYCLIN L1. We propose that changes in ambient temperature affect the relative abundance of CDKG1 transcripts and this in turn translates into differential CDKG1 protein expression coordinating the alternative splicing of ATU2AF65A. This article is protected by copyright. All rights reserved. AU - Cavallari, Nicola AU - Nibau, Candida AU - Fuchs, Armin AU - Dadarou, Despoina AU - Barta, Andrea AU - Doonan, John ID - 403 IS - 6 JF - The Plant Journal TI - The cyclin‐dependent kinase G group defines a thermo‐sensitive alternative splicing circuit modulating the expression of Arabidopsis ATU 2AF 65A VL - 94 ER - TY - CONF AB - Imprecision in timing can sometimes be beneficial: Metric interval temporal logic (MITL), disabling the expression of punctuality constraints, was shown to translate to timed automata, yielding an elementary decision procedure. We show how this principle extends to other forms of dense-time specification using regular expressions. By providing a clean, automaton-based formal framework for non-punctual languages, we are able to recover and extend several results in timed systems. Metric interval regular expressions (MIRE) are introduced, providing regular expressions with non-singular duration constraints. We obtain that MIRE are expressively complete relative to a class of one-clock timed automata, which can be determinized using additional clocks. Metric interval dynamic logic (MIDL) is then defined using MIRE as temporal modalities. We show that MIDL generalizes known extensions of MITL, while translating to timed automata at comparable cost. AU - Ferrere, Thomas ID - 156 TI - The compound interest in relaxing punctuality VL - 10951 ER - TY - JOUR AB - The biotrophic pathogen Ustilago maydis, the causative agent of corn smut disease, infects one of the most important crops worldwide – Zea mays. To successfully colonize its host, U. maydis secretes proteins, known as effectors, that suppress plant defense responses and facilitate the establishment of biotrophy. In this work, we describe the U. maydis effector protein Cce1. Cce1 is essential for virulence and is upregulated during infection. Through microscopic analysis and in vitro assays, we show that Cce1 is secreted from hyphae during filamentous growth of the fungus. Strikingly, Δcce1 mutants are blocked at early stages of infection and induce callose deposition as a plant defense response. Cce1 is highly conserved among smut fungi and the Ustilago bromivora ortholog complemented the virulence defect of the SG200Δcce1 deletion strain. These data indicate that Cce1 is a core effector with apoplastic localization that is essential for U. maydis to infect its host. AU - Seitner, Denise AU - Uhse, Simon AU - Gallei, Michelle C AU - Djamei, Armin ID - 104 IS - 10 JF - Molecular Plant Pathology TI - The core effector Cce1 is required for early infection of maize by Ustilago maydis VL - 19 ER - TY - JOUR AB - Hanemaaijer et al. (Molecular Ecology, 27, 2018) describe the genetic consequences of the introgression of an insecticide resistance allele into a mosquito population. Linked alleles initially increased, but many of these later declined. It is hard to determine whether this decline was due to counter‐selection, rather than simply to chance. AU - Barton, Nicholas H ID - 40 IS - 24 JF - Molecular Ecology SN - 1365294X TI - The consequences of an introgression event VL - 27 ER - TY - JOUR AB - In zebrafish larvae, it is the cell type that determines how the cell responds to a chemokine signal. AU - Alanko, Jonna H AU - Sixt, Michael K ID - 5861 JF - eLife SN - 2050084X TI - The cell sets the tone VL - 7 ER - TY - JOUR AB - The trafficking of subcellular cargos in eukaryotic cells crucially depends on vesicle budding, a process mediated by ARF-GEFs (ADP-ribosylation factor guanine nucleotide exchange factors). In plants, ARF-GEFs play essential roles in endocytosis, vacuolar trafficking, recycling, secretion, and polar trafficking. Moreover, they are important for plant development, mainly through controlling the polar subcellular localization of PIN-FORMED (PIN) transporters of the plant hormone auxin. Here, using a chemical genetics screen in Arabidopsis thaliana, we identified Endosidin 4 (ES4), an inhibitor of eukaryotic ARF-GEFs. ES4 acts similarly to and synergistically with the established ARF-GEF inhibitor Brefeldin A and has broad effects on intracellular trafficking, including endocytosis, exocytosis, and vacuolar targeting. Additionally, Arabidopsis and yeast (Sacharomyces cerevisiae) mutants defective in ARF-GEF show altered sensitivity to ES4. ES4 interferes with the activation-based membrane association of the ARF1 GTPases, but not of their mutant variants that are activated independently of ARF-GEF activity. Biochemical approaches and docking simulations confirmed that ES4 specifically targets the SEC7 domain-containing ARF-GEFs. These observations collectively identify ES4 as a chemical tool enabling the study of ARF-GEF-mediated processes, including ARF-GEF-mediated plant development. AU - Kania, Urszula AU - Nodzyński, Tomasz AU - Lu, Qing AU - Hicks, Glenn R AU - Nerinckx, Wim AU - Mishev, Kiril AU - Peurois, Francois AU - Cherfils, Jacqueline AU - De, Rycke Riet Maria AU - Grones, Peter AU - Robert, Stéphanie AU - Russinova, Eugenia AU - Friml, Jirí ID - 147 IS - 10 JF - The Plant Cell SN - 1040-4651 TI - The inhibitor Endosidin 4 targets SEC7 domain-type ARF GTPase exchange factors and interferes with sub cellular trafficking in eukaryotes VL - 30 ER - TY - JOUR AB - The root cap protects the stem cell niche of angiosperm roots from damage. In Arabidopsis, lateral root cap (LRC) cells covering the meristematic zone are regularly lost through programmed cell death, while the outermost layer of the root cap covering the tip is repeatedly sloughed. Efficient coordination with stem cells producing new layers is needed to maintain a constant size of the cap. We present a signalling pair, the peptide IDA-LIKE1 (IDL1) and its receptor HAESA-LIKE2 (HSL2), mediating such communication. Live imaging over several days characterized this process from initial fractures in LRC cell files to full separation of a layer. Enhanced expression of IDL1 in the separating root cap layers resulted in increased frequency of sloughing, balanced with generation of new layers in a HSL2-dependent manner. Transcriptome analyses linked IDL1-HSL2 signalling to the transcription factors BEARSKIN1/2 and genes associated with programmed cell death. Mutations in either IDL1 or HSL2 slowed down cell division, maturation and separation. Thus, IDL1-HSL2 signalling potentiates dynamic regulation of the homeostatic balance between stem cell division and sloughing activity. AU - Shi, Chun Lin AU - Von Wangenheim, Daniel AU - Herrmann, Ullrich AU - Wildhagen, Mari AU - Kulik, Ivan AU - Kopf, Andreas AU - Ishida, Takashi AU - Olsson, Vilde AU - Anker, Mari Kristine AU - Albert, Markus AU - Butenko, Melinka A AU - Felix, Georg AU - Sawa, Shinichiro AU - Claassen, Manfred AU - Friml, Jirí AU - Aalen, Reidunn B ID - 146 IS - 8 JF - Nature Plants TI - The dynamics of root cap sloughing in Arabidopsis is regulated by peptide signalling VL - 4 ER - TY - JOUR AB - People sometimes make their admirable deeds and accomplishments hard to spot, such as by giving anonymously or avoiding bragging. Such ‘buried’ signals are hard to reconcile with standard models of signalling or indirect reciprocity, which motivate costly pro-social behaviour by reputational gains. To explain these phenomena, we design a simple game theory model, which we call the signal-burying game. This game has the feature that senders can bury their signal by deliberately reducing the probability of the signal being observed. If the signal is observed, however, it is identified as having been buried. We show under which conditions buried signals can be maintained, using static equilibrium concepts and calculations of the evolutionary dynamics. We apply our analysis to shed light on a number of otherwise puzzling social phenomena, including modesty, anonymous donations, subtlety in art and fashion, and overeagerness. AU - Hoffman, Moshe AU - Hilbe, Christian AU - Nowak, Martin ID - 293 JF - Nature Human Behaviour TI - The signal-burying game can explain why we obscure positive traits and good deeds VL - 2 ER - TY - JOUR AB - The derivation of effective evolution equations is central to the study of non-stationary quantum many-body systems, and widely used in contexts such as superconductivity, nuclear physics, Bose–Einstein condensation and quantum chemistry. We reformulate the Dirac–Frenkel approximation principle in terms of reduced density matrices and apply it to fermionic and bosonic many-body systems. We obtain the Bogoliubov–de Gennes and Hartree–Fock–Bogoliubov equations, respectively. While we do not prove quantitative error estimates, our formulation does show that the approximation is optimal within the class of quasifree states. Furthermore, we prove well-posedness of the Bogoliubov–de Gennes equations in energy space and discuss conserved quantities AU - Benedikter, Niels P AU - Sok, Jérémy AU - Solovej, Jan ID - 455 IS - 4 JF - Annales Henri Poincare TI - The Dirac–Frenkel principle for reduced density matrices and the Bogoliubov–de Gennes equations VL - 19 ER - TY - JOUR AB - The interface of physics and biology pro-vides a fruitful environment for generatingnew concepts and exciting ways forwardto understanding living matter. Examplesof successful studies include the estab-lishment and readout of morphogen gra-dients during development, signal pro-cessing in protein and genetic networks,the role of fluctuations in determining thefates of cells and tissues, and collectiveeffects in proteins and in tissues. It is nothard to envision that significant further ad-vances will translate to societal benefitsby initiating the development of new de-vices and strategies for curing disease.However, research at the interface posesvarious challenges, in particular for youngscientists, and current institutions arerarely designed to facilitate such scientificprograms. In this Letter, we propose aninternational initiative that addressesthese challenges through the establish-ment of a worldwide network of platformsfor cross-disciplinary training and incuba-tors for starting new collaborations. AU - Bauer, Guntram AU - Fakhri, Nikta AU - Kicheva, Anna AU - Kondev, Jané AU - Kruse, Karsten AU - Noji, Hiroyuki AU - Riveline, Daniel AU - Saunders, Timothy AU - Thatta, Mukund AU - Wieschaus, Eric ID - 314 IS - 4 JF - Cell Systems TI - The science of living matter for tomorrow VL - 6 ER - TY - JOUR AB - We re-examine the model of Kirkpatrick and Barton for the spread of an inversion into a local population. This model assumes that local selection maintains alleles at two or more loci, despite immigration of alternative alleles at these loci from another population. We show that an inversion is favored because it prevents the breakdown of linkage disequilibrium generated by migration; the selective advantage of an inversion is proportional to the amount of recombination between the loci involved, as in other cases where inversions are selected for. We derive expressions for the rate of spread of an inversion; when the loci covered by the inversion are tightly linked, these conditions deviate substantially from those proposed previously, and imply that an inversion can then have only a small advantage. AU - Charlesworth, Brian AU - Barton, Nicholas H ID - 565 IS - 1 JF - Genetics TI - The spread of an inversion with migration and selection VL - 208 ER - TY - JOUR AB - We prove that in Thomas–Fermi–Dirac–von Weizsäcker theory, a nucleus of charge Z > 0 can bind at most Z + C electrons, where C is a universal constant. This result is obtained through a comparison with Thomas-Fermi theory which, as a by-product, gives bounds on the screened nuclear potential and the radius of the minimizer. A key ingredient of the proof is a novel technique to control the particles in the exterior region, which also applies to the liquid drop model with a nuclear background potential. AU - Frank, Rupert AU - Phan Thanh, Nam AU - Van Den Bosch, Hanne ID - 446 IS - 3 JF - Communications on Pure and Applied Mathematics TI - The ionization conjecture in Thomas–Fermi–Dirac–von Weizsäcker theory VL - 71 ER - TY - JOUR AB - In this issue of GENETICS, a new method for detecting natural selection on polygenic traits is developed and applied to sev- eral human examples ( Racimo et al. 2018 ). By de fi nition, many loci contribute to variation in polygenic traits, and a challenge for evolutionary ge neticists has been that these traits can evolve by small, nearly undetectable shifts in allele frequencies across each of many, typically unknown, loci. Recently, a helpful remedy has arisen. Genome-wide associ- ation studies (GWAS) have been illuminating sets of loci that can be interrogated jointly for c hanges in allele frequencies. By aggregating small signal s of change across many such loci, directional natural selection is now in principle detect- able using genetic data, even for highly polygenic traits. This is an exciting arena of progress – with these methods, tests can be made for selection associated with traits, and we can now study selection in what may be its most prevalent mode. The continuing fast pace of GWAS publications suggest there will be many more polygenic tests of selection in the near future, as every new GWAS is an opportunity for an accom- panying test of polygenic selection. However, it is important to be aware of complications th at arise in interpretation, especially given that these studies may easily be misinter- preted both in and outside the evolutionary genetics commu- nity. Here, we provide context for understanding polygenic tests and urge caution regarding how these results are inter- preted and reported upon more broadly. AU - Novembre, John AU - Barton, Nicholas H ID - 430 IS - 4 JF - Genetics TI - Tread lightly interpreting polygenic tests of selection VL - 208 ER - TY - JOUR AB - Sex-biased genes are central to the study of sexual selection, sexual antagonism, and sex chromosome evolution. We describe a comprehensive de novo assembled transcriptome in the common frog Rana temporaria based on five developmental stages and three adult tissues from both sexes, obtained from a population with karyotypically homomorphic but genetically differentiated sex chromosomes. This allows the study of sex-biased gene expression throughout development, and its effect on the rate of gene evolution while accounting for pleiotropic expression, which is known to negatively correlate with the evolutionary rate. Overall, sex-biased genes had little overlap among developmental stages and adult tissues. Late developmental stages and gonad tissues had the highest numbers of stage-or tissue-specific genes. We find that pleiotropic gene expression is a better predictor than sex bias for the evolutionary rate of genes, though it often interacts with sex bias. Although genetically differentiated, the sex chromosomes were not enriched in sex-biased genes, possibly due to a very recent arrest of XY recombination. These results extend our understanding of the developmental dynamics, tissue specificity, and genomic localization of sex-biased genes. AU - Ma, Wen AU - Veltsos, Paris AU - Toups, Melissa A AU - Rodrigues, Nicolas AU - Sermier, Roberto AU - Jeffries, Daniel AU - Perrin, Nicolas ID - 199 IS - 6 JF - Genes TI - Tissue specificity and dynamics of sex biased gene expression in a common frog population with differentiated, yet homomorphic, sex chromosomes VL - 9 ER - TY - JOUR AB - A central goal in theoretical neuroscience is to predict the response properties of sensory neurons from first principles. To this end, “efficient coding” posits that sensory neurons encode maximal information about their inputs given internal constraints. There exist, however, many variants of efficient coding (e.g., redundancy reduction, different formulations of predictive coding, robust coding, sparse coding, etc.), differing in their regimes of applicability, in the relevance of signals to be encoded, and in the choice of constraints. It is unclear how these types of efficient coding relate or what is expected when different coding objectives are combined. Here we present a unified framework that encompasses previously proposed efficient coding models and extends to unique regimes. We show that optimizing neural responses to encode predictive information can lead them to either correlate or decorrelate their inputs, depending on the stimulus statistics; in contrast, at low noise, efficiently encoding the past always predicts decorrelation. Later, we investigate coding of naturalistic movies and show that qualitatively different types of visual motion tuning and levels of response sparsity are predicted, depending on whether the objective is to recover the past or predict the future. Our approach promises a way to explain the observed diversity of sensory neural responses, as due to multiple functional goals and constraints fulfilled by different cell types and/or circuits. AU - Chalk, Matthew J AU - Marre, Olivier AU - Tkacik, Gasper ID - 543 IS - 1 JF - PNAS TI - Toward a unified theory of efficient, predictive, and sparse coding VL - 115 ER - TY - JOUR AB - Cell shape is determined by a balance of intrinsic properties of the cell as well as its mechanochemical environment. Inhomogeneous shape changes underlie many morphogenetic events and involve spatial gradients in active cellular forces induced by complex chemical signaling. Here, we introduce a mechanochemical model based on the notion that cell shape changes may be induced by external diffusible biomolecules that influence cellular contractility (or equivalently, adhesions) in a concentration-dependent manner—and whose spatial profile in turn is affected by cell shape. We map out theoretically the possible interplay between chemical concentration and cellular structure. Besides providing a direct route to spatial gradients in cell shape profiles in tissues, we show that the dependence on cell shape helps create robust mechanochemical gradients. AU - Dasbiswas, Kinjal AU - Hannezo, Claude-Edouard B AU - Gov, Nir ID - 421 IS - 4 JF - Biophysical Journal TI - Theory of eppithelial cell shape transitions induced by mechanoactive chemical gradients VL - 114 ER - TY - JOUR AB - African cichlids display a remarkable assortment of jaw morphologies, pigmentation patterns, and mating behaviors. In addition to this previously documented diversity, recent studies have documented a rich diversity of sex chromosomes within these fishes. Here we review the known sex-determination network within vertebrates, and the extraordinary number of sex chromosomes systems segregating in African cichlids. We also propose a model for understanding the unusual number of sex chromosome systems within this clade. AU - Gammerdinger, William J AU - Kocher, Thomas ID - 63 IS - 10 JF - Genes TI - Unusual diversity of sex chromosomes in African cichlid fishes VL - 9 ER - TY - JOUR AB - The thermodynamic description of many-particle systems rests on the assumption of ergodicity, the ability of a system to explore all allowed configurations in the phase space. Recent studies on many-body localization have revealed the existence of systems that strongly violate ergodicity in the presence of quenched disorder. Here, we demonstrate that ergodicity can be weakly broken by a different mechanism, arising from the presence of special eigenstates in the many-body spectrum that are reminiscent of quantum scars in chaotic non-interacting systems. In the single-particle case, quantum scars correspond to wavefunctions that concentrate in the vicinity of unstable periodic classical trajectories. We show that many-body scars appear in the Fibonacci chain, a model with a constrained local Hilbert space that has recently been experimentally realized in a Rydberg-atom quantum simulator. The quantum scarred eigenstates are embedded throughout the otherwise thermalizing many-body spectrum but lead to direct experimental signatures, as we show for periodic recurrences that reproduce those observed in the experiment. Our results suggest that scarred many-body bands give rise to a new universality class of quantum dynamics, opening up opportunities for the creation of novel states with long-lived coherence in systems that are now experimentally realizable. AU - Turner, Christopher AU - Michailidis, Alexios AU - Abanin, Dmitry AU - Serbyn, Maksym AU - Papić, Zlatko ID - 296 JF - Nature Physics TI - Weak ergodicity breaking from quantum many-body scars VL - 14 ER - TY - JOUR AB - We study the Fokker-Planck equation derived in the large system limit of the Markovian process describing the dynamics of quantitative traits. The Fokker-Planck equation is posed on a bounded domain and its transport and diffusion coefficients vanish on the domain's boundary. We first argue that, despite this degeneracy, the standard no-flux boundary condition is valid. We derive the weak formulation of the problem and prove the existence and uniqueness of its solutions by constructing the corresponding contraction semigroup on a suitable function space. Then, we prove that for the parameter regime with high enough mutation rate the problem exhibits a positive spectral gap, which implies exponential convergence to equilibrium.Next, we provide a simple derivation of the so-called Dynamic Maximum Entropy (DynMaxEnt) method for approximation of observables (moments) of the Fokker-Planck solution, which can be interpreted as a nonlinear Galerkin approximation. The limited applicability of the DynMaxEnt method inspires us to introduce its modified version that is valid for the whole range of admissible parameters. Finally, we present several numerical experiments to demonstrate the performance of both the original and modified DynMaxEnt methods. We observe that in the parameter regimes where both methods are valid, the modified one exhibits slightly better approximation properties compared to the original one. AU - Bodova, Katarina AU - Haskovec, Jan AU - Markowich, Peter ID - 607 JF - Physica D: Nonlinear Phenomena TI - Well posedness and maximum entropy approximation for the dynamics of quantitative traits VL - 376-377 ER - TY - JOUR AB - We developed a method to calculate two-photon processes in quantum mechanics that replaces the infinite summation over the intermediate states by a perturbation expansion. This latter consists of a series of commutators that involve position, momentum, and Hamiltonian quantum operators. We analyzed several single- and many-particle cases for which a closed-form solution to the perturbation expansion exists, as well as more complicated cases for which a solution is found by convergence. Throughout the article, Rayleigh and Raman scattering are taken as examples of two-photon processes. The present method provides a clear distinction between the Thomson scattering, regarded as classical scattering, and quantum contributions. Such a distinction lets us derive general results concerning light scattering. Finally, possible extensions to the developed formalism are discussed. AU - Fratini, Filippo AU - Safari, Laleh AU - Amaro, Pedro AU - Santos, José ID - 294 IS - 4 JF - Physical Review A - Atomic, Molecular, and Optical Physics TI - Two-photon processes based on quantum commutators VL - 97 ER -