30 research outputs found
Design, Implementation, and Outcomes of a Three-week Pharmacy Bridging Course
Objective. To evaluate the design, implementation, and outcomes of a three-week pharmacy bridging course (PBC) covering five math and science areas for first-year doctor of pharmacy students in fall 2015
Characterization of Hepatoma-Derived Growth Factor-Related Protein 2 Interactions with Heterochromatin
The expression of genetic information is tightly controlled by chromatin regulatory proteins, including those in the heterochromatin gene repression family. Many of these regulatory proteins work together on the chromatin substrate to precisely regulate gene expression during mammalian development, giving rise to many different tissues in higher organisms from a fixed genomic template. Here we identify and characterize the interactions of two related heterochromatin regulatory proteins, heterochromatin protein 1 alpha (HP1α) and M-phase phosphoprotein 8 (MPP8), with hepatoma-derived growth factor-related protein 2 (HRP2). We find in biochemical experiments that HRP2 copurifies and co-sediments with heterochromatin-associated proteins, including HP1α and MPP8. Using the Chromatin in vivo Assay in multiple cell types, we demonstrate that HP1α-mediated gene repression dynamics are altered by the presence of HRP2. Furthermore, the knockout of HRP2 in MDA-MB-231 cells results in significant changes to chromatin structure and stability, which alter gene expression patterns. Here, we detail a mechanism by which HRP2 contributes to epigenetic transcriptional regulation through engagement with heterochromatin-associated proteins to stabilize the chromatin landscape and influence gene expression
Pharmacologic Inhibition of the Anaphase-Promoting Complex Induces A Spindle Checkpoint-Dependent Mitotic Arrest in the Absence of Spindle Damage
SummaryMicrotubule inhibitors are important cancer drugs that induce mitotic arrest by activating the spindle assembly checkpoint (SAC), which, in turn, inhibits the ubiquitin ligase activity of the anaphase-promoting complex (APC). Here, we report a small molecule, tosyl-L-arginine methyl ester (TAME), which binds to the APC and prevents its activation by Cdc20 and Cdh1. A prodrug of TAME arrests cells in metaphase without perturbing the spindle, but nonetheless the arrest is dependent on the SAC. Metaphase arrest induced by a proteasome inhibitor is also SAC dependent, suggesting that APC-dependent proteolysis is required to inactivate the SAC. We propose that mutual antagonism between the APC and the SAC yields a positive feedback loop that amplifies the ability of TAME to induce mitotic arrest
Ubiquitin Chains Are Remodeled at the Proteasome by Opposing Ubiquitin Ligase and Deubiquitinating Activities
SummaryThe ubiquitin ligase Hul5 was recently identified as a component of the proteasome, a multisubunit protease that degrades ubiquitin-protein conjugates. We report here a proteasome-dependent conjugating activity of Hul5 that endows proteasomes with the capacity to extend ubiquitin chains. hul5 mutants show reduced degradation of multiple proteasome substrates in vivo, suggesting that the polyubiquitin signal that targets substrates to the proteasome can be productively amplified at the proteasome. However, the products of Hul5 conjugation are subject to disassembly by a proteasome-bound deubiquitinating enzyme, Ubp6. A hul5 null mutation suppresses a ubp6 null mutation, suggesting that a balance of chain-extending and chain-trimming activities is required for proper proteasome function. As the association of Hul5 with proteasomes was found to be strongly stabilized by Ubp6, these enzymes may be situated in proximity to one another. We propose that through dynamic remodeling of ubiquitin chains, proteasomes actively regulate substrate commitment to degradation
Roving UAV IED interdiction system
In support of the Naval Postgraduate School's Systems Engineering Capstone, a project team was formed from Cohort 311-093A to perform an analysis on the possibility of utilizing Unmanned Air Vehicles (UAVs) in campaign against improvised explosive devices (IEDs). The goal of the project was to determine if a weapon system is feasible to increase capabilities to the warfighter in the fight against the IED threat. The project scope was limited to the UAV classes with local (squad/battalion) control to provide an organic increase in capabilitiesspecifically Tier I (man-portable) and Tier II (tactical) families of UAVs. Modeling and simulation, warhead analysis, and a cost analysis were used to score the proposed alternatives on specific Key Performance Parameters. This information was analyzed and a recommendation was made to only arm the Tier II UAV using a small missile.http://archive.org/details/rovinguaviedinte109456957Approved for public release; distribution is unlimited
Characterization of Hepatoma-Derived Growth Factor-Related Protein 2 Interactions with Heterochromatin
The expression of genetic information is tightly controlled by chromatin regulatory proteins, including those in the heterochromatin gene repression family. Many of these regulatory proteins work together on the chromatin substrate to precisely regulate gene expression during mammalian development, giving rise to many different tissues in higher organisms from a fixed genomic template. Here we identify and characterize the interactions of two related heterochromatin regulatory proteins, heterochromatin protein 1 alpha (HP1α) and M-phase phosphoprotein 8 (MPP8), with hepatoma-derived growth factor-related protein 2 (HRP2). We find in biochemical experiments that HRP2 copurifies and co-sediments with heterochromatin-associated proteins, including HP1α and MPP8. Using the Chromatin in vivo Assay in multiple cell types, we demonstrate that HP1α-mediated gene repression dynamics are altered by the presence of HRP2. Furthermore, the knockout of HRP2 in MDA-MB-231 cells results in significant changes to chromatin structure and stability, which alter gene expression patterns. Here, we detail a mechanism by which HRP2 contributes to epigenetic transcriptional regulation through engagement with heterochromatin-associated proteins to stabilize the chromatin landscape and influence gene expression
Tethering of Lsh at the <i>Oct4</i> locus promotes gene repression associated with epigenetic changes
<p>Lsh is a chromatin remodeling factor that regulates DNA methylation and chromatin function in mammals. The dynamics of these chromatin changes and whether they are directly controlled by Lsh remain unclear. To understand the molecular mechanisms of Lsh chromatin controlled regulation of gene expression, we established a tethering system that recruits a Gal4-Lsh fusion protein to an engineered <i>Oct4</i> locus through Gal4 binding sites in murine embryonic stem (ES) cells. We examined the molecular epigenetic events induced by Lsh binding including: histone modification, DNA methylation and chromatin accessibility to determine nucleosome occupancy before and after embryonic stem cell differentiation. Our results indicate that Lsh assists gene repression upon binding to the <i>Oct4</i> promoter region. Furthermore, we detected less chromatin accessibility and reduced active histone modifications at the tethered site in undifferentiated ES, while GFP reporter gene expression and DNA methylation patterns remained unchanged at this stage. Upon differentiation, association of Lsh promotes transcriptional repression of the reporter gene accompanied by the increase of repressive histone marks and a gain of DNA methylation at distal and proximal <i>Oct4</i> enhancer sites. Taken together, this approach allowed us to examine Lsh mediated epigenetic regulation as a dynamic process and revealed chromatin accessibility changes as the primary consequence of Lsh function.</p