Communication between distinct subunit interfaces of the cohesin complex promotes its topological entrapment of DNA.

Cohesin mediates higher order chromosome structure. Its biological activities require topological entrapment of DNA within a lumen(s) formed by cohesin subunits. The reversible dissociation of cohesins Smc3p and Mcd1p subunits is postulated to form a regulated gate that allows DNA entry and exit into the lumen. We assessed gate-independent functions of this interface in yeast using a fusion protein that joins Smc3p to Mcd1p. We show that in vivo all the regulators of cohesin promote DNA binding of cohesin by mechanisms independent of opening this gate. Furthermore, we show that this interface has a gate-independent activity essential for cohesin to bind chromosomes. We propose that this interface regulates DNA entrapment by controlling the opening and closing of one or more distal interfaces formed by cohesin subunits, likely by inducing a conformation change in cohesin. Furthermore, cohesin regulators modulate the interface to control both DNA entrapment and cohesin functions after DNA binding

Religious Monopolies and the Commodification of Religion

In recent years, the number of countries in which a dominant church receives state aid and other forms of preferential treatment has increased. Dominant religions and their supporters in the former Soviet bloc and elsewhere often argue that special benefits and protection are warranted based upon the unique history and contribution of the dominant church to the identity, history, and culture of the country, and the interests of the state and its citizens. Because of the distinctive status of religion and its importance to national and cultural identity, special protection, especially against foreign and other outside influence, is deemed necessary. Although the spiritual realm is putatively treated as being a special situation requiring special protection, the arguments in favor of religious protection bear a curious resemblance to arguments in favor of protection made by monopolists and other protected industries in the economic sphere. This article compares the arguments in favor of protection made by dominant religious groups with arguments in favor of protection by monopolists and protected industries, and concludes that in their pleas for special treatment, religious monopolists make arguments that closely parallel the arguments made by their economic counterparts. Rather than resulting in religion being treated as unique and different, protectionist arguments result in religion being treated much like any other market commodity. We conclude that because religious freedom is a fundamental human right, arguments promoting state protection of dominant religions should be viewed with suspicion

B16: Chikungunya Virus Time Course Infection of Human Macrophages

Chikungunya virus (CHIKV) is an Alphavirus spread by Aedes spp. mosquitoes and is responsible for infecting 1.1 million people per year worldwide, including a large epidemic in the western hemisphere in 2014-2015. During the body’s immune response to CHIKV, human macrophages become infected after phagocytosis of CHIKV and undergo induced apoptosis, catalyzing the virus spread in the body. It is presently unclear what macrophage genes, functions, and intracellular signaling pathways are impacted during the early, intermediate, and late stages of CHIKV infection. Therefore we quantified the transcriptional response of human macrophage cells infected with CHIKV at two different timepoints

Mesobot : An Autonomous Underwater Vehicle for Tracking and Sampling Midwater Targets

Mesobot, a new class of autonomous underwater vehicle, will address specific unmet needs for observing slow-moving targets in the midwater ocean. Mesobot will track targets such as zooplankton, fish, and descending particle aggregates using a control system based on stereo cameras and a combination of thrusters and a variable buoyancy system. The vehicle will also be able to collect biogeochemical and environmental DNA (eDNA) samples using a pumped filter sampler

H3K36 Methylation Promotes Longevity by Enhancing Transcriptional Fidelity

Epigenetic mechanisms, including histone post-translational modifications, control longevity in diverse organisms. Relatedly, loss of proper transcriptional regulation on a global scale is an emerging phenomenon of shortened life span, but the specific mechanisms linking these observations remain to be uncovered. Here, we describe a life span screen in Saccharomyces cerevisiae that is designed to identify amino acid residues of histones that regulate yeast replicative aging. Our results reveal that lack of sustained histone H3K36 methylation is commensurate with increased cryptic transcription in a subset of genes in old cells and with shorter life span. In contrast, deletion of the K36me2/3 demethylase Rph1 increases H3K36me3 within these genes, suppresses cryptic transcript initiation, and extends life span. We show that this aging phenomenon is conserved, as cryptic transcription also increases in old worms. We propose that epigenetic misregulation in aging cells leads to loss of transcriptional precision that is detrimental to life span, and, importantly, this acceleration in aging can be reversed by restoring transcriptional fidelity

Choline transporter gene variation is associated with attention-deficit hyperactivity disorder

The neurotransmitter acetylcholine (ACh) plays a critical role in brain circuits mediating motor control, attention, learning and memory. Cholinergic dysfunction is associated with multiple brain disorders including Alzheimer’s Disease, addiction, schizophrenia and Attention-Deficit Hyperactivity Disorder (ADHD). The presynaptic choline transporter (CHT, SLC5A7) is the major, rate-limiting determinant of ACh production in the brain and periphery and is consequently upregulated during tasks that require sustained attention. Given the contribution of central cholinergic circuits to the control of movement and attention, we hypothesized that functional CHT gene variants might impact risk for ADHD. We performed a case-control study, followed by family-based association tests on a separate cohort, of two purportedly functional CHT polymorphisms (coding variant Ile89Val (rs1013940) and a genomic SNP 3’ of the CHT gene (rs333229), affording both a replication sample and opportunities to reduce potential population stratification biases. Initial genotyping of pediatric ADHD subjects for two purportedly functional CHT alleles revealed a 2–3 fold elevation of the Val89 allele (n = 100; P = 0.02) relative to healthy controls, as well as a significant decrease of the 3’SNP minor allele in Caucasian male subjects (n = 60; P = 0.004). In family based association tests, we found significant overtransmission of the Val89 variant to children with a Combined subtype diagnosis (OR = 3.16; P = 0.01), with an increased Odds Ratio for a haplotype comprising both minor alleles. These studies show evidence of cholinergic deficits in ADHD, particularly for subjects with the Combined subtype, and, if replicated, may encourage further consideration of cholinergic agonist therapy in the disorder

Elevated Proteasome Capacity Extends Replicative Lifespan in Saccharomyces cerevisiae

Aging is characterized by the accumulation of damaged cellular macromolecules caused by declining repair and elimination pathways. An integral component employed by cells to counter toxic protein aggregates is the conserved ubiquitin/proteasome system (UPS). Previous studies have described an age-dependent decline of proteasomal function and increased longevity correlates with sustained proteasome capacity in centenarians and in naked mole rats, a long-lived rodent. Proof for a direct impact of enhanced proteasome function on longevity, however, is still lacking. To determine the importance of proteasome function in yeast aging, we established a method to modulate UPS capacity by manipulating levels of the UPS–related transcription factor Rpn4. While cells lacking RPN4 exhibit a decreased non-adaptable proteasome pool, loss of UBR2, an ubiquitin ligase that regulates Rpn4 turnover, results in elevated Rpn4 levels, which upregulates UPS components. Increased UPS capacity significantly enhances replicative lifespan (RLS) and resistance to proteotoxic stress, while reduced UPS capacity has opposing consequences. Despite tight transcriptional co-regulation of the UPS and oxidative detoxification systems, the impact of proteasome capacity on lifespan is independent of the latter, since elimination of Yap1, a key regulator of the oxidative stress response, does not affect lifespan extension of cells with higher proteasome capacity. Moreover, since elevated proteasome capacity results in improved clearance of toxic huntingtin fragments in a yeast model for neurodegenerative diseases, we speculate that the observed lifespan extension originates from prolonged elimination of damaged proteins in old mother cells. Epistasis analyses indicate that proteasome-mediated modulation of lifespan is at least partially distinct from dietary restriction, Tor1, and Sir2. These findings demonstrate that UPS capacity determines yeast RLS by a mechanism that is distinct from known longevity pathways and raise the possibility that interventions to promote enhanced proteasome function will have beneficial effects on longevity and age-related disease in humans

Bradley Ellingboe’s Requiem: Influences and Analysis for Performance

Bradley Ellingboe (b. 1956) is an American composer who resides in Albuquerque, New Mexico. Ellingboe has over one hundred and twenty choral compositions and four larger choral-orchestral works in print. Requiem, composed in 2001, was Ellingboe’s first major work for choir and orchestra. Bradley Ellingboe’s study of the music of Edvard Grieg (1843-1907) and his prolonged exposure to Norwegian folk song and Lutheranism have influenced his melodic, textual, and formal choices in his Requiem. An understanding of these influences will aid conductors in creating stylistically appropriate performances of Requiem. Bradley Ellingboe was raised in a Norwegian-American family in Lakeville, Minnesota. To give further context, a brief biography of the composer and highlights of the history of requiem mass are included in this document. In this document, I discuss the importance of the inclusion of the folk tune, Jeg lagde mig saa silde and a recurring cello solo that serves as a Leitmotif throughout Requiem. Through motivic analysis the influence of Norwegian folk music and the music of Edvard Grieg are further revealed. The discussion of the architecture, text choices, and the emotional progression in Requiem reveal the influence of Ellingboe’s Lutheran faith. This document also includes a chapter that provides rehearsal and performance suggestions for conductors

Mechanisms of Cohesin Function Revealed by Analysis of Smc3

A central problem in biology is how genetic material is organized and inherited during cell divisions without loss of information. The conserved protein complex cohesin functions to ensure chromosomes are partitioned equally when cells divide. Cohesin mediates sister chromatid cohesion, chromosome condensation, efficient repair of DNA damage and regulation of transcription. The activity by which cohesin performs these functions is through DNA tethering. Tethering can occur between two sister chromatids or within a single chromatid to bring together two separate positions along its length. Within this dissertation, I will describe novel insights into the mechanism by which cohesin performs these critical activities on chromosomes. I chose to study this problem in the budding yeast Saccharomyces cerevisiae because of the unparalleled genetic tools available in this model eukaryote.Cohesin consists of four core subunits referred to in yeast as Mcd1p, Scc3p, Smc1p, and Smc3p, whereas spatiotemporal control of cohesin activity depends on auxiliary factors. To better understand cohesin architecture and regulation, I performed a genetic screen to identify novel mutants of the Smc3p subunit. Characterization of these mutants has revealed functions for previously undescribed regions of Smc3p and new activities for previously described domains that further our understanding of this complex molecular machine. First, I describe a series of mutations at the interface between Smc3p and Mcd1p termed the DNA “exit gate”. This investigation revealed an unexpected role for this interface in loading cohesin on chromosomes. Second, I reveal a novel role for the Smc3p hinge domain in cohesion maintenance that is independent of its ability to stably bind chromosomes. This discovery lends additional weight against a simple “embrace” model for DNA tethering by cohesin still supported by many in this field. Moreover, this observation suggests that communication between the Smc3p hinge, Mcd1p, and regulator Pds5p is required for cohesion maintenance. Finally, I show that a specific region in the middle of the cohesin ring is critical for a step in the process of cohesin loading onto chromosomes. This result is surprising since it suggests that a contortion of the cohesin ring is critical for it to productively bind chromosomes. In sum, this dissertation advances our understanding of the mechanism by which cohesin functions and supports a variation of the “handcuff” model in which an activity after DNA binding is required for cohesin to achieve tethering