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Neuronal activity promotes axon regeneration [Neuroscience]

PNAS Early Edition Articles - Mon, 02/01/2016 - 14:03
Cell-type–specific G protein-coupled receptor (GPCR) signaling regulates distinct neuronal responses to various stimuli and is essential for axon guidance and targeting during development. However, its function in axonal regeneration in the mature CNS remains elusive. We found that subtypes of intrinsically photosensitive retinal ganglion cells (ipRGCs) in mice maintained high...

Quasi-liquid layers on ice are formed kinetically [Physics]

PNAS Early Edition Articles - Mon, 02/01/2016 - 14:03
Surfaces of ice are covered with thin liquid water layers, called quasi-liquid layers (QLLs), even below their melting point (0 °C), which govern a wide variety of phenomena in nature. We recently found that two types of QLL phases appear that exhibit different morphologies (droplets and thin layers) [Sazaki G....

Like-charged complex coacervates [Biophysics and Computational Biology]

PNAS Early Edition Articles - Mon, 02/01/2016 - 14:03
It is well known that polyelectrolyte complexes and coacervates can form on mixing oppositely charged polyelectrolytes in aqueous solutions, due to mainly electrostatic attraction between the oppositely charged polymers. Here, we report the first (to the best of our knowledge) complexation and coacervation of two positively charged polyelectrolytes, which provides...

Metaanalytically decoding the human striatum [Psychological and Cognitive Sciences]

PNAS Early Edition Articles - Mon, 02/01/2016 - 14:03
Decades of animal and human neuroimaging research have identified distinct, but overlapping, striatal zones, which are interconnected with separable corticostriatal circuits, and are crucial for the organization of functional systems. Despite continuous efforts to subdivide the human striatum based on anatomical and resting-state functional connectivity, characterizing the different psychological processes...

Nanoscale orientational imaging in biofilaments [Applied Physical Sciences]

PNAS Early Edition Articles - Mon, 02/01/2016 - 14:03
Essential cellular functions as diverse as genome maintenance and tissue morphogenesis rely on the dynamic organization of filamentous assemblies. For example, the precise structural organization of DNA filaments has profound consequences on all DNA-mediated processes including gene expression, whereas control over the precise spatial arrangement of cytoskeletal protein filaments is...

Winner takes it all [Psychological and Cognitive Sciences]

PNAS Early Edition Articles - Mon, 02/01/2016 - 14:03
Winning a competition engenders subsequent unrelated unethical behavior. Five studies reveal that after a competition has taken place winners behave more dishonestly than competition losers. Studies 1 and 2 demonstrate that winning a competition increases the likelihood of winners to steal money from their counterparts in a subsequent unrelated task....

Enhanced TTP mRNA stability and inflammation [Immunology and Inflammation]

PNAS Early Edition Articles - Mon, 02/01/2016 - 14:03
Tristetraprolin (TTP) is an inducible, tandem zinc-finger mRNA binding protein that binds to adenylate-uridylate–rich elements (AREs) in the 3′-untranslated regions (3′UTRs) of specific mRNAs, such as that encoding TNF, and increases their rates of deadenylation and turnover. Stabilization of Tnf mRNA and other cytokine transcripts in TTP-deficient mice results in...

Molecular interactions between AT and ACP [Biochemistry]

PNAS Early Edition Articles - Mon, 02/01/2016 - 14:03
Acyltransferases (ATs) are key determinants of building block specificity in polyketide biosynthesis. Despite the importance of protein–protein interactions between AT and acyl carrier protein (ACP) during the acyltransfer reaction, the mechanism of ACP recognition by AT is not understood in detail. Herein, we report the crystal structure of AT VinK,...

Rate-limiting processes of bacterial cytokinesis [Microbiology]

PNAS Early Edition Articles - Mon, 02/01/2016 - 14:03
Bacterial cytokinesis is accomplished by the essential ‘divisome’ machinery. The most widely conserved divisome component, FtsZ, is a tubulin homolog that polymerizes into the ‘FtsZ-ring’ (‘Z-ring’). Previous in vitro studies suggest that Z-ring contraction serves as a major constrictive force generator to limit the progression of cytokinesis. Here, we applied...

Tle1 regulates inflammation in vivo [Immunology and Inflammation]

PNAS Early Edition Articles - Mon, 02/01/2016 - 14:03
Tle1 (transducin-like enhancer of split 1) is a corepressor that interacts with a variety of DNA-binding transcription factors and has been implicated in many cellular functions; however, physiological studies are limited. Tle1-deficient (Tle1Δ/Δ) mice, although grossly normal at birth, exhibit skin defects, lung hypoplasia, severe runting, poor body condition, and...

Diversity-generating biosynthesis [Chemistry]

PNAS Early Edition Articles - Mon, 02/01/2016 - 14:03
A conventional metabolic pathway leads to a specific product. In stark contrast, there are diversity-generating metabolic pathways that naturally produce different chemicals, sometimes of great diversity. We demonstrate that for one such pathway, tru, each ensuing metabolic step is slower, in parallel with the increasing potential chemical divergence generated as...

Marine mixotrophy increases ecological efficiency [Environmental Sciences]

PNAS Early Edition Articles - Mon, 02/01/2016 - 14:03
Mixotrophic plankton, which combine the uptake of inorganic resources and the ingestion of living prey, are ubiquitous in marine ecosystems, but their integrated biogeochemical impacts remain unclear. We address this issue by removing the strict distinction between phytoplankton and zooplankton from a global model of the marine plankton food web....

K14+ tumor clusters form polyclonal metastases [Cell Biology]

PNAS Early Edition Articles - Mon, 02/01/2016 - 14:03
Recent genomic studies challenge the conventional model that each metastasis must arise from a single tumor cell and instead reveal that metastases can be composed of multiple genetically distinct clones. These intriguing observations raise the question: How do polyclonal metastases emerge from the primary tumor? In this study, we used...

Inhibitor of serine synthesis [Biochemistry]

PNAS Early Edition Articles - Mon, 02/01/2016 - 14:03
Cancer cells reprogram their metabolism to promote growth and proliferation. The genetic evidence pointing to the importance of the amino acid serine in tumorigenesis is striking. The gene encoding the enzyme 3-phosphoglycerate dehydrogenase (PHGDH), which catalyzes the first committed step of serine biosynthesis, is overexpressed in tumors and cancer cell...

Gdnf cKO in peritubular myoid cells [Developmental Biology]

PNAS Early Edition Articles - Mon, 02/01/2016 - 14:03
Spermatogonial stem cells (SSCs) are a subpopulation of undifferentiated spermatogonia located in a niche at the base of the seminiferous epithelium delimited by Sertoli cells and peritubular myoid (PM) cells. SSCs self-renew or differentiate into spermatogonia that proliferate to give rise to spermatocytes and maintain spermatogenesis. Glial cell line-derived neurotrophic...

Distal and proximal modules within the IgH 3'RR [Immunology and Inflammation]

PNAS Early Edition Articles - Mon, 02/01/2016 - 14:03
As a master regulator of functional Ig heavy chain (IgH) expression, the IgH 3′ regulatory region (3′RR) controls multiple transcription events at various stages of B-cell ontogeny, from newly formed B cells until the ultimate plasma cell stage. The IgH 3′RR plays a pivotal role in early B-cell receptor expression,...

GHRH antagonist reduces hyperlipidemia in T1D [Medical Sciences]

PNAS Early Edition Articles - Mon, 02/01/2016 - 14:03
Dyslipidemia associated with triglyceride-rich lipoproteins (TRLs) represents an important residual risk factor for cardiovascular and chronic kidney disease in patients with type 1 diabetes (T1D). Levels of growth hormone (GH) are elevated in T1D, which aggravates both hyperglycemia and dyslipidemia. The hypothalamic growth hormone-releasing hormone (GHRH) regulates the release of...

Decisions affect saccades [Neuroscience]

PNAS Early Edition Articles - Mon, 02/01/2016 - 14:03
It is well established that ongoing cognitive functions affect the trajectories of limb movements mediated by corticospinal circuits, suggesting an interaction between cognition and motor action. Although there are also many demonstrations that decision formation is reflected in the ongoing neural activity in oculomotor brain circuits, it is not known...
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