Functional and Biochemical Characterization of Dib1\u27s Role in Pre-Messenger RNA Splicing

The spliceosome is a dynamic macromolecular machine that undergoes a series of conformational rearrangements as it transitions between the several states required for accurate splicing. The transition from the B to Bact is a key part of spliceosome assembly and is defined by the departure of several proteins, including essential U5 component Dib1. Recent structural studies suggest that Dib1 has a role in preventing premature spliceosome activation, as it is positioned adjacent to the U6 snRNA ACAGAGA and the U5 loop I, but its mechanism is unknown. Our data indicate that Dib1 is a robust protein that tolerates incorporation of many mutations, even at positions thought to be key for its folding stability. However, we have identified two temperature-sensitive mutants that stall in vitro splicing prior to the first catalytic step and block assembly at the B complex. In addition, Dib1 readily exchanges in splicing extracts despite being a central component of the U5 snRNP, suggesting that the binding site of Dib1 is flexible. Structural analyses show that the overall conformation of Dib1 and the mutants are not affected by temperature, so the temperature sensitive defects most likely result from altered interactions between Dib1 and other spliceosomal components. Together, these data lead to a new understanding of Dib1\u27s role in the B to Bact transition and provide a model for how dynamic protein–RNA interactions contribute to the correct assembly of a complex molecular machine

Advancing the Application of Design of Experiments (DOE) to Synthetic Theater Operations Research Model (STORM) Data

NPS NRP Project PosterThe Navy uses simulation-based campaign analysis to help measure risk for investment options for how best to equip, organize, supply, maintain, train, and employ our naval forces. The Synthetic Theater Operations Research Model (STORM) is a stochastic simulation model used to support campaign analysis by the U.S. Navy, Marine Corps, and Air Force. Building, testing, running, and analyzing campaign scenarios in STORM can be a complex, time-consuming process. The goal of this research is to apply Design Of Experiment (DOE) methods in the selection and creation of Design Points (DPs) to minimize the number of modeling runs required for meaningful comparisons. Another objective is to understand how best DOE methods can complement traditional baseline and excursion modeling. In addition to regular reviews, the research deliverables will include: (1) a final brief and/or technical report, in addition to student theses (if applicable); (2) all findings, methods, and data used in the study; and (3) appropriate conference or journal papers related to this research.N8 - Integration of Capabilities & ResourcesThis research is supported by funding from the Naval Postgraduate School, Naval Research Program (PE 0605853N/2098). https://nps.edu/nrpChief of Naval Operations (CNO)Approved for public release. Distribution is unlimited.

Advancing the Application of Design of Experiments (DOE) to Synthetic Theater Operations Research Model (STORM) Data

NPS NRP Technical ReportThe Navy uses simulation-based campaign analysis to help measure risk for investment options for how best to equip, organize, supply, maintain, train, and employ our naval forces. The Synthetic Theater Operations Research Model (STORM) is a stochastic simulation model used to support campaign analysis by the U.S. Navy, Marine Corps, and Air Force. Building, testing, running, and analyzing campaign scenarios in STORM can be a complex, time-consuming process. The goal of this research is to apply Design Of Experiment (DOE) methods in the selection and creation of Design Points (DPs) to minimize the number of modeling runs required for meaningful comparisons. Another objective is to understand how best DOE methods can complement traditional baseline and excursion modeling. In addition to regular reviews, the research deliverables will include: (1) a final brief and/or technical report, in addition to student theses (if applicable); (2) all findings, methods, and data used in the study; and (3) appropriate conference or journal papers related to this research.N8 - Integration of Capabilities & ResourcesThis research is supported by funding from the Naval Postgraduate School, Naval Research Program (PE 0605853N/2098). https://nps.edu/nrpChief of Naval Operations (CNO)Approved for public release. Distribution is unlimited.

Advancing the Application of Design of Experiments (DOE) to Synthetic Theater Operations Research Model (STORM) Data

NPS NRP Executive SummaryThe Navy uses simulation-based campaign analysis to help measure risk for investment options for how best to equip, organize, supply, maintain, train, and employ our naval forces. The Synthetic Theater Operations Research Model (STORM) is a stochastic simulation model used to support campaign analysis by the U.S. Navy, Marine Corps, and Air Force. Building, testing, running, and analyzing campaign scenarios in STORM can be a complex, time-consuming process. The goal of this research is to apply Design Of Experiment (DOE) methods in the selection and creation of Design Points (DPs) to minimize the number of modeling runs required for meaningful comparisons. Another objective is to understand how best DOE methods can complement traditional baseline and excursion modeling. In addition to regular reviews, the research deliverables will include: (1) a final brief and/or technical report, in addition to student theses (if applicable); (2) all findings, methods, and data used in the study; and (3) appropriate conference or journal papers related to this research.N8 - Integration of Capabilities & ResourcesThis research is supported by funding from the Naval Postgraduate School, Naval Research Program (PE 0605853N/2098). https://nps.edu/nrpChief of Naval Operations (CNO)Approved for public release. Distribution is unlimited.

The short term debt vs. long term debt puzzle: a model for the optimal mix

This paper argues that the existing finance literature is inadequate with respect to its coverage of capital structure of small and medium sized enterprises (SMEs). In particular it is argued that the cost of equity (being both conceptually ill defined and empirically non quantifiable) is not applicable to the capital structure decisions for a large proportion of SMEs and the optimal capital structure depends only on the mix of short and long term debt. The paper then presents a model, developed by practitioners for optimising the debt mix and demonstrates its practical application using an Italian firm's debt structure as a case study

Spatiotemporal progression of ubiquitin-proteasome system inhibition after status epilepticus suggests protective adaptation against hippocampal injury.

BACKGROUND: The ubiquitin-proteasome-system (UPS) is the major intracellular pathway leading to the degradation of unwanted and/or misfolded soluble proteins. This includes proteins regulating cellular survival, synaptic plasticity and neurotransmitter signaling; processes controlling excitability thresholds that are altered by epileptogenic insults. Dysfunction of the UPS has been reported to occur in a brain region- and cell-specific manner and contribute to disease progression in acute and chronic brain diseases. Prolonged seizures, status epilepticus, may alter UPS function but there has been no systematic attempt to map when and where this occurs in vivo or to determine the consequences of proteasome inhibition on seizure-induced brain injury. METHOD: To determine whether seizures lead to an impairment of the UPS, we used a mouse model of status epilepticus whereby seizures are triggered by an intra-amygdala injection of kainic acid. Status epilepticus in this model causes cell death in selected brain areas, in particular the ipsilateral CA3 subfield of the hippocampus, and the development of epilepsy after a short latent period. To monitor seizure-induced dysfunction of the UPS we used a UPS inhibition reporter mouse expressing the ubiquitin fusion degradation substrate ubiquitin(G76V)-green fluorescent protein. Treatment with the specific proteasome inhibitor epoxomicin was used to establish the impact of proteasome inhibition on seizure-induced pathology. RESULTS AND CONCLUSIONS: Our studies show that status epilepticus induced by intra-amygdala kainic acid causes select spatio-temporal UPS inhibition which is most evident in damage-resistant regions of the hippocampus, including CA1 pyramidal and dentate granule neurons then appears later in astrocytes. In support of this exerting a beneficial effect, injection of mice with the proteasome inhibitor epoxomicin protected the normally vulnerable hippocampal CA3 subfield from seizure-induced neuronal death in the model. These studies reveal brain region- and cell-specific UPS impairment occurs after seizures and suggest UPS inhibition can protect against seizure-induced brain damage. Identifying networks or pathways regulated through the proteasome after seizures may yield novel target genes for the treatment of seizure-induced cell death and possibly epilepsy

Huntingtin-mediated axonal transport requires arginine methylation by PRMT6

The huntingtin (HTT) protein transports various organelles, including vesicles containing neurotrophic factors, from embryonic development throughout life. To better understand how HTT mediates axonal transport and why this function is disrupted in Huntington's disease (HD), we study vesicle-associated HTT and find that it is dimethylated at a highly conserved arginine residue (R118) by the protein arginine methyltransferase 6 (PRMT6). Without R118 methylation, HTT associates less with vesicles, anterograde trafficking is diminished, and neuronal death ensues—very similar to what occurs in HD. Inhibiting PRMT6 in HD cells and neurons exacerbates mutant HTT (mHTT) toxicity and impairs axonal trafficking, whereas overexpressing PRMT6 restores axonal transport and neuronal viability, except in the presence of a methylation-defective variant of mHTT. In HD flies, overexpressing PRMT6 rescues axonal defects and eclosion. Arginine methylation thus regulates HTT-mediated vesicular transport along the axon, and increasing HTT methylation could be of therapeutic interest for HD

Genome-wide association and HLA fine-mapping studies identify risk loci and genetic pathways underlying allergic rhinitis

Allergic rhinitis is the most common clinical presentation of allergy, affecting 400 million people worldwide, with increasing incidence in westernized countries1,2. To elucidate the genetic architecture and understand the underlying disease mechanisms, we carried out a meta-analysis of allergic rhinitis in 59,762 cases and 152,358 controls of European ancestry and identified a total of 41 risk loci for allergic rhinitis, including 20 loci not previously associated with allergic rhinitis, which were confirmed in a replication phase of 60,720 cases and 618,527 controls. Functional annotation implicated genes involved in various immune pathways, and fine mapping of the HLA region suggested amino acid variants important for antigen binding. We further performed genome-wide association study (GWAS) analyses of allergic sensitization against inhalant allergens and nonallergic rhinitis, which suggested shared genetic mechanisms across rhinitis-related traits. Future studies of the identified loci and genes might identify novel targets for treatment and prevention of allergic rhinitis