Proceedings of the Natural Academy of Sciences

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  • miR-223 regulates cholesterol metabolism [Medical Sciences]
    [Oct 2014]

    MicroRNAs (miRNAs) regulate a wide variety of biological processes and contribute to metabolic homeostasis. Here, we demonstrate that microRNA-223 (miR-223), an miRNA previously associated with inflammation, also controls multiple mechanisms associated with cholesterol metabolism. miR-223 promoter activity and mature levels were found to be linked to cellular cholesterol states in...
    Categories: Journal Articles
  • Spinopathy in mutant UBQLN2 transgenic mice [Medical Sciences]
    [Oct 2014]

    Mutations in the gene encoding ubiquilin2 (UBQLN2) cause amyotrophic lateral sclerosis (ALS), frontotemporal type of dementia, or both. However, the molecular mechanisms are unknown. Here, we show that ALS/dementia-linked UBQLN2P497H transgenic mice develop neuronal pathology with ubiquilin2/ubiquitin/p62-positive inclusions in the brain, especially in the hippocampus, recapitulating several key pathological features...
    Categories: Journal Articles
  • RvD1 blocks calcium kinase signaling to limit LTB4 [Medical Sciences]
    [Oct 2014]

    Imbalances between proinflammatory and proresolving mediators can lead to chronic inflammatory diseases. The balance of arachidonic acid-derived mediators in leukocytes is thought to be achieved through intracellular localization of 5-lipoxygenase (5-LOX): nuclear 5-LOX favors the biosynthesis of proinflammatory leukotriene B4 (LTB4), whereas, in theory, cytoplasmic 5-LOX could favor the biosynthesis...
    Categories: Journal Articles
  • Precisely modulated SaPI interference with phage [Microbiology]
    [Oct 2014]

    Having gone to great evolutionary lengths to develop resistance to bacteriophages, bacteria have come up with resistance mechanisms directed at every aspect of the bacteriophage life cycle. Most genes involved in phage resistance are carried by plasmids and other mobile genetic elements, including bacteriophages and their relatives. A very special...
    Categories: Journal Articles
  • Smallest coding covalently closed circular RNA [Microbiology]
    [Oct 2014]

    The highly structured (64% GC) covalently closed circular (CCC) RNA (220 nt) of the virusoid associated with rice yellow mottle virus codes for a 16-kDa highly basic protein using novel modalities for coding, translation, and gene expression. This CCC RNA is the smallest among all known viroids and virusoids and...
    Categories: Journal Articles
  • Individually unique brain representations [Neuroscience]
    [Oct 2014]

    The unique way in which each of us perceives the world must arise from our brain representations. If brain imaging could reveal an individual’s unique mental representation, it could help us understand the biological substrate of our individual experiential worlds in mental health and disease. However, imaging studies of object...
    Categories: Journal Articles
  • Misfolded intermediates dominate {alpha}-helix folding [Physics]
    [Oct 2014]

    Helices are the “hydrogen atoms” of biomolecular complexity; the DNA/RNA double hairpin and protein α-helix ubiquitously form the building blocks of life’s constituents at the nanometer scale. Nevertheless, the formation processes of these structures, especially the dynamical pathways and rates, remain challenging to predict and control. Here, we present a...
    Categories: Journal Articles
  • cAMP and TRIP8b competing interaction for HCN2 [Physiology]
    [Oct 2014]

    cAMP signaling in the brain mediates several higher order neural processes. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels directly bind cAMP through their cytoplasmic cyclic nucleotide binding domain (CNBD), thus playing a unique role in brain function. Neuronal HCN channels are also regulated by tetratricopeptide repeat-containing Rab8b interacting protein (TRIP8b), an auxiliary...
    Categories: Journal Articles
  • Superheated ice inside Antarctic fishes [Physiology]
    [Oct 2014]

    Antifreeze proteins (AFPs) of polar marine teleost fishes are widely recognized as an evolutionary innovation of vast adaptive value in that, by adsorbing to and inhibiting the growth of internalized environmental ice crystals, they prevent death by inoculative freezing. Paradoxically, systemic accumulation of AFP-stabilized ice could also be lethal. Whether...
    Categories: Journal Articles
  • Titin's role in muscle structure and function [Physiology]
    [Oct 2014]

    Titin, the largest protein known, forms a giant filament in muscle where it spans the half sarcomere from Z disk to M band. Here we genetically targeted a stretch of 14 immunoglobulin-like and fibronectin type 3 domains that comprises the I-band/A-band (IA) junction and obtained a viable mouse model. Super-resolution...
    Categories: Journal Articles
  • FBH1 regulates CCA1 expression [Plant Biology]
    [Oct 2014]

    In Arabidopsis, the circadian clock allows the plant to coordinate daily external signals with internal processes, conferring enhanced fitness and growth vigor. Although external cues such as temperature can entrain the clock, an important feature of the clock is the ability to maintain a relatively constant period over a range...
    Categories: Journal Articles
  • Enhanced saccharification mutants in Brachypodium [Plant Biology]
    [Oct 2014]

    Lignocellulosic plant biomass is an attractive feedstock for the production of sustainable biofuels, but the commercialization of such products is hampered by the high costs of processing this material into fermentable sugars (saccharification). One approach to lowering these costs is to produce crops with cell walls that are more susceptible...
    Categories: Journal Articles
  • Long-distance negative feedback loop in nodulation [Plant Biology]
    [Oct 2014]

    Autoregulatory negative-feedback loops play important roles in fine-balancing tissue and organ development. Such loops are composed of short-range intercellular signaling pathways via cell–cell communications. On the other hand, leguminous plants use a long-distance negative-feedback system involving root–shoot communication to control the number of root nodules, root lateral organs that harbor...
    Categories: Journal Articles
  • Virus-activated plant siRNAs produced by RDR1 [Plant Biology]
    [Oct 2014]

    Antiviral immunity controlled by RNA interference (RNAi) in plants and animals is thought to specifically target only viral RNAs by the virus-derived small interfering RNAs (siRNAs). Here we show that activation of antiviral RNAi in Arabidopsis plants is accompanied by the production of an abundant class of endogenous siRNAs mapped...
    Categories: Journal Articles
  • Noncell autonomous stem cell induction in plants [Plant Biology]
    [Oct 2014]

    Cell–cell communication is essential for multicellular development and, consequently, evolution has brought about an array of distinct mechanisms serving this purpose. Consistently, induction and maintenance of stem cell fate by noncell autonomous signals is a feature shared by many organisms and may depend on secreted factors, direct cell–cell contact, matrix...
    Categories: Journal Articles
  • Learning stimulus bundles [Psychological and Cognitive Sciences]
    [Oct 2014]

    The order in which stimuli are presented in an experiment has long been recognized to influence behavior. Previous accounts have often attributed the effect of stimulus order to the mechanisms with which people process information. We propose that stimulus order influences cognition because it is an important cue for learning...
    Categories: Journal Articles
  • Encoding auditory objects in songbird forebrain [Psychological and Cognitive Sciences]
    [Oct 2014]

    Auditory neurophysiology has demonstrated how basic acoustic features are mapped in the brain, but it is still not clear how multiple sound components are integrated over time and recognized as an object. We investigated the role of statistical learning in encoding the sequential features of complex sounds by recording neuronal...
    Categories: Journal Articles
  • Neurobiology of preschool beat synchronization [Psychological and Cognitive Sciences]
    [Oct 2014]

    Temporal cues are important for discerning word boundaries and syllable segments in speech; their perception facilitates language acquisition and development. Beat synchronization and neural encoding of speech reflect precision in processing temporal cues and have been linked to reading skills. In poor readers, diminished neural precision may contribute to rhythmic...
    Categories: Journal Articles
  • Ni-induced H3K9me2 domain disruption and spreading [Systems Biology]
    [Oct 2014]

    Investigations into the genomic landscape of histone modifications in heterochromatic regions have revealed histone H3 lysine 9 dimethylation (H3K9me2) to be important for differentiation and maintaining cell identity. H3K9me2 is associated with gene silencing and is organized into large repressive domains that exist in close proximity to active genes, indicating...
    Categories: Journal Articles
  • In This Issue [This Week in PNAS]
    [Oct 2014]

    Tunable, aluminum nanorods for full-color displays Colors produced by aluminum nanorod-based pixels. Visual display technologies that employ inorganic materials to produce color have the potential to improve the durability and extend the lifespan of color displays. But inorganic materials are limited in their ability to produce vivid blue colors. Jana...
    Categories: Journal Articles