Over a long and distinguished career in international affairs, Michael Williams stepped forward to tackle some of the most difficult conflict situations of the late 20th and early 21st centuries.

Invitation Only

Event participants

Robin Niblett, Director, Chatham House; Chair, NATO Group of Policy Experts
Xenia Wickett, Project Director, US; Acting Dean, Academy for Leadership in International Affairs, Chatham House

Chair
Paola Totaro, President, Foreign Press Association

Research Event

Event participants

Dr Constanze Stelzenmüller, Senior Transatlantic Fellow, German Marshall Fund
Chair: Xenia Wickett, Project Director, US; Acting Dean, The Academy, Chatham House

Invitation Only Research Event

Event participants

Xenia Wickett, Project Director, US; Dean, Academy for Leadership in International Affairs, Chatham House
Dr Christian Moelling, International Security Division Associate, SWP-Berlin

Histone H2B monoubiquitylation (H2Bub1) has central functions in multiple DNA-templated processes, including gene transcription, DNA repair, and replication. H2Bub1 also is required for the trans-histone regulation of H3K4 and H3K79 methylation. Although previous studies have elucidated the basic mechanisms that establish and remove H2Bub1, we have only an incomplete understanding of how H2Bub1 is regulated. We report here that the histone H4 basic patch regulates H2Bub1. Yeast cells with arginine-to-alanine mutations in the H4 basic patch (H42RA) exhibited a significant loss of global H2Bub1. H42RA mutant yeast strains also displayed chemotoxin sensitivities similar to, but less severe than, strains containing a complete loss of H2Bub1. We found that the H4 basic patch regulates H2Bub1 levels independently of interactions with chromatin remodelers and separately from its regulation of H3K79 methylation. To measure H2B ubiquitylation and deubiquitination kinetics in vivo, we used a rapid and reversible optogenetic tool, the light-inducible nuclear exporter, to control the subcellular location of the H2Bub1 E3 ligase, Bre1. The ability of Bre1 to ubiquitylate H2B was unaffected in the H42RA mutant. In contrast, H2Bub1 deubiquitination by SAGA-associated Ubp8, but not by Ubp10, increased in the H42RA mutant. Consistent with a function for the H4 basic patch in regulating SAGA deubiquitinase activity, we also detected increased SAGA-mediated histone acetylation in H4 basic patch mutants. Our findings uncover that the H4 basic patch has a regulatory function in SAGA-mediated histone modifications.

We previously reported that overexpression of cytochrome P450 family 24 subfamily A member 1 (CYP24A1) increases lung cancer cell proliferation by activating RAS signaling and that CYP24A1 knockdown inhibits tumor growth. However, the mechanism of CYP24A1-mediated cancer cell proliferation remains unclear. Here, we conducted cell synchronization and biochemical experiments in lung adenocarcinoma cells, revealing a link between CYP24A1 and anaphase-promoting complex (APC), a key cell cycle regulator. We demonstrate that CYP24A1 expression is cell cycle–dependent; it was higher in the G2-M phase and diminished upon G1 entry. CYP24A1 has a functional destruction box (D-box) motif that allows binding with two APC adaptors, CDC20-homologue 1 (CDH1) and cell division cycle 20 (CDC20). Unlike other APC substrates, however, CYP24A1 acted as a pseudo-substrate, inhibiting CDH1 activity and promoting mitotic progression. Conversely, overexpression of a CYP24A1 D-box mutant compromised CDH1 binding, allowing CDH1 hyperactivation, thereby hastening degradation of its substrates cyclin B1 and CDC20, and accumulation of the CDC20 substrate p21, prolonging mitotic exit. These activities also occurred with a CYP24A1 isoform 2 lacking the catalytic cysteine (Cys-462), suggesting that CYP24A1's oncogenic potential is independent of its catalytic activity. CYP24A1 degradation reduced clonogenic survival of mutant KRAS-driven lung cancer cells, and calcitriol treatment increased CYP24A1 levels and tumor burden in Lsl-KRASG12D mice. These results disclose a catalytic activity-independent growth-promoting role of CYP24A1 in mutant KRAS-driven lung cancer. This suggests that CYP24A1 could be therapeutically targeted in lung cancers in which its expression is high.

Mammalian cytochrome P450 enzymes often metabolize many pharmaceuticals and other xenobiotics, a feature that is valuable in a biotechnology setting. However, extant P450 enzymes are typically relatively unstable, with T50 values of ∼30–40 °C. Reconstructed ancestral cytochrome P450 enzymes tend to have variable substrate selectivity compared with related extant forms, but they also have higher thermostability and therefore may be excellent tools for commercial biosynthesis of important intermediates, final drug molecules, or drug metabolites. The mammalian ancestor of the cytochrome P450 1B subfamily was herein characterized structurally and functionally, revealing differences from the extant human CYP1B1 in ligand binding, metabolism, and potential molecular contributors to its thermostability. Whereas extant human CYP1B1 has one molecule of α-naphthoflavone in a closed active site, we observed that subtle amino acid substitutions outside the active site in the ancestor CYP1B enzyme yielded an open active site with four ligand copies. A structure of the ancestor with 17β-estradiol revealed only one molecule in the active site, which still had the same open conformation. Detailed comparisons between the extant and ancestor forms revealed increases in electrostatic and aromatic interactions between distinct secondary structure elements in the ancestral forms that may contribute to their thermostability. To the best of our knowledge, this represents the first structural evaluation of a reconstructed ancestral cytochrome P450, revealing key features that appear to contribute to its thermostability.

Research Event

Event participants

Sumantra Bose, Professor of International and Comparative Politics, LSE; Author, Transforming India: Challenges to the World's Largest Democracy

This article is part 4 of a series on Fantasy Fortifications by Toni Šušnjar.

Building a Fort

Build time of a castle, depending on design and available funds, may last from half a year to half a century. It also depends on the situation before the building: a ruined castle is a half-built castle after all, and rennovating (and/or updating) walls is much cheaper than building new ones. This can be seen with city of Dubrovnik, where (massive) medieval fortifications were, after the fall of Constantinople in 1453., reinforced with outer line of walls to reinforce them against cannon fire.

Both build time and extent of fortifications depend on material (financial, logistical, humane) capacities of the builder, as well as the perceived need. Many castles were never finished for lack of resources.

Builders are professionals; peasants, soldiers and other amateurs were used for muscle work only. This means that they have to be paid, and many in fact travel from a building place to a building place. Beaumaris Castle in England required 400 masons and 1,000 assistants to be built in a nearly record time (from 1278 to 1280).

Types of Castles
Motte and bailey castle

Motte and bailey castle is the earliest and simplest type of a castle.

Continue reading Fantasy Fortifications — Part 4: Types of Castles at Mythic Scribes.

Jorge H. Capdevila
Feb 1, 2000; 41:163-181
Reviews

HNF4α is a nuclear receptor produced as 12 isoforms from two promoters by alternative splicing. To characterize the transcriptional capacities of all 12 HNF4α isoforms, stable lines expressing each isoform were generated. The entire transcriptome associated with each isoform was analyzed as well as their respective interacting proteome. Major differences were noted in the transcriptional function of these isoforms. The α1 and α2 isoforms were the strongest regulators of gene expression whereas the α3 isoform exhibited significantly reduced activity. The α4, α5, and α6 isoforms, which use an alternative first exon, were characterized for the first time, and showed a greatly reduced transcriptional potential with an inability to recognize the consensus response element of HNF4α. Several transcription factors and coregulators were identified as potential specific partners for certain HNF4α isoforms. An analysis integrating the vast amount of omics data enabled the identification of transcriptional regulatory mechanisms specific to certain HNF4α isoforms, hence demonstrating the importance of considering all isoforms given their seemingly diverse functions.

Telomeres are specific nucleoprotein structures that are located at the ends of linear eukaryotic chromosomes and play crucial roles in genomic stability. Telomere DNA consists of simple repeats of a short G-rich sequence: TTAGGG in mammals and TTTAGGG in most plants. In recent years, the mammalian telomeric G-rich repeats have been shown to form G-quadruplex (G4) structures, which are crucial for modulating telomere functions. Surprisingly, even though plant telomeres are essential for plant growth, development, and environmental adaptions, only few reports exist on plant telomeric G4 DNA (pTG4). Here, using bulk and single-molecule assays, including CD spectroscopy, and single-molecule FRET approaches, we comprehensively characterized the structure and dynamics of a typical plant telomeric sequence, d[GGG(TTTAGGG)3]. We found that this sequence can fold into mixed G4s in potassium, including parallel and antiparallel structures. We also directly detected intermediate dynamic transitions, including G-hairpin, parallel G-triplex, and antiparallel G-triplex structures. Moreover, we observed that pTG4 is unfolded by the AtRecQ2 helicase but not by AtRecQ3. The results of our work shed light on our understanding about the existence, topological structures, stability, intermediates, unwinding, and functions of pTG4.

Invitation Only Research Event

Invitation Only Research Event

Invitation Only Research Event

• Review of Chan Wook Park's Stoker.
• What We Watched: Dredd, The Artist is Present, Side by Side, Silver Lining's Playbook, Arrested Development, All-Star Celebrity Apprentice, Bob's Burgers.

• Gravity Review
• What We Watched: Room 237, The American Scream, Bless Me Ultima, Ernest Scared Stupid, The Conjuring, V/H/S 2, H. H. Holmes: America's First Serial Killer & Attack on Titan.
• Gravity Spoiler Discussion (after the outro music). 

The autosomal dominant disorder Schnyder corneal dystrophy (SCD) is caused by mutations in UbiA prenyltransferase domain-containing protein-1 (UBIAD1), which uses geranylgeranyl pyrophosphate (GGpp) to synthesize the vitamin K₂ subtype menaquinone-4 (MK-4). SCD is characterized by opacification of the cornea, owing to aberrant build-up of cholesterol in the tissue. We previously discovered that sterols stimulate association of UBIAD1 with ER-localized HMG-CoA reductase, which catalyzes a rate-limiting step in the synthesis of cholesterol and nonsterol isoprenoids, including GGpp. Binding to UBIAD1 inhibits sterol-accelerated ER-associated degradation (ERAD) of reductase and permits continued synthesis of GGpp in cholesterol-replete cells. GGpp disrupts UBIAD1-reductase binding and thereby allows for maximal ERAD of reductase as well as ER-to-Golgi translocation of UBIAD1. SCD-associated UBIAD1 is refractory to GGpp-mediated dissociation from reductase and remains sequestered in the ER to inhibit ERAD. Here, we report development of a biochemical assay for UBIAD1-mediated synthesis of MK-4 in isolated membranes and intact cells. Using this assay, we compared enzymatic activity of WT UBIAD1 with that of SCD-associated variants. Our studies revealed that SCD-associated UBIAD1 exhibited reduced MK-4 synthetic activity, which may result from its reduced affinity for GGpp. Sequestration in the ER protects SCD-associated UBIAD1 from autophagy and allows intracellular accumulation of the mutant protein, which amplifies the inhibitory effect on reductase ERAD. These findings have important implications not only for the understanding of SCD etiology but also for the efficacy of cholesterol-lowering statin therapy, which becomes limited, in part, because of UBIAD1-mediated inhibition of reductase ERAD.

Adipocytes take up long chain FAs through diffusion and protein-mediated transport, whereas FA efflux is considered to occur by diffusion. To identify potential membrane proteins that are involved in regulating FA flux in adipocytes, the expression levels of 55 membrane transporters without known function were screened in subcutaneous adipose samples from obese patients before and after bariatric surgery using branched DNA methodology. Among the 33 solute carrier (SLC) transporter family members screened, the expression of 14 members showed significant changes before and after bariatric surgery. One of them, Slc43a3, increased about 2.5-fold after bariatric surgery. Further investigation demonstrated that Slc43a3 is highly expressed in murine adipose tissue and induced during adipocyte differentiation in primary preadipocytes and in OP9 cells. Knockdown of Slc43a3 with siRNA in differentiated OP9 adipocytes reduced both basal and forskolin-stimulated FA efflux, while also increasing FA uptake and lipid droplet accumulation. In contrast, overexpression of Slc43a3 decreased FA uptake in differentiated OP9 cells and resulted in decreased lipid droplet accumulation. Therefore, Slc43a3 seems to regulate FA flux in adipocytes, functioning as a positive regulator of FA efflux and as a negative regulator of FA uptake.

Expert

Expert

Tratamento genético foi testado em Layla Richards que estava desenganada pelos médicos. Especialistas ressaltam que os resultados são iniciais e podem não ocorrer em outros pacientes.

The post Terapia inédita reverte leucemia incurável em bebê de 1 ano appeared first on Saúde Próspera.

Exame poderá detectar a doença na fase inicial. Pesquisadores da Faculdade de Medicina Osteopática da Universidade de Rowan, nos Estados Unidos, afirmam que estão perto de desenvolver um exame de sangue para detectar Alzheimer com precisão, o que dar...

The post Teste de sangue para detectar Alzheimer está próximo da realidade appeared first on Saúde Próspera.

Publication Date: Apr 10 2020 The SEC will withdraw the existing approval order and the fund will become subject to the requirements of Rule 6c-11 and Nasdaq Rule 5704....

Publication Date: Apr 10 2020 Yes. According to the SEC, once an ETF becomes eligible to operate under Rule 6c-11 and elects to list on Nasdaq under Nasdaq Rule 5704, the existing order related to that fund (and all other funds under that exemptive order) will be rescinded. Once a fund is listed under Nasdaq Rule 5704, it will not be able to relist under Nasdaq Rule 5705(b) (Index Fund Shares) or Nasdaq Rule 5735 (Managed Fund Shares) unless a new exemptive relief order is obtained from the SEC....

Publication Date: Apr 10 2020 Funds listed under Nasdaq Rule 5704 are required to submit an annual certification regarding the funds compliance with Rule 6c-11 during the most recent fiscal year. The certification is required within 30 calendar days of a fund’s fiscal year end. The certification can be found here....

Publication Date: Apr 10 2020 ETFs that meet the definition of “Exchange Traded Fund” in Nasdaq Rule 5704(a)(1)(A) are eligible to be considered for listing pursuant to Nasdaq Rule 5704. ETFs that are excluded from operating pursuant to Rule 6c-11 under the Investment Company Act of 1940 are not eligible to list under Nasdaq Rule 5704....

Publication Date: Apr 10 2020 New Fund Launches In addition to completing the Listing Application, new funds are required to complete a certification prior to receiving approval of an initial listing application. The certification can be found here. Listing Transfers In addition to completing the Listing Application, funds switching from another market to Nasdaq are required to complete a certification regarding compliance with SEC Rule 6c-11. The certification must be completed prior to...

The leak exposed millions of records with full names, emails, user conversations, payment logs, and IP addresses dating back to March.

Invitation Only Research Event

Invitation Only Research Event

Sea ice is one of the least understood components of our climate. Naturally its abundance or scarcity is a telling sign of climate change, but sea ice is also an important actor in change as well, insulating the ocean and reflecting sunlight. A branch of mathematics called percolation theory helps explain how salt water travels through sea ice, a process that is crucial both to the amount of sea ice present and to the microscopic communities that sustain polar ecosystems. By taking samples, doing on-site experiments, and then incorporating the data into models of porous materials, mathematicians are working to understand sea ice and help refine climate predictions. Using probability, numerical analysis, and partial differential equations, researchers have recently shown that the permeability of sea ice is similar to that of some sedimentary rocks in the earth.s crust, even though the substances are otherwise dissimilar. One major difference between the two is the drastic changes in permeability of sea ice, from total blockage to clear passage, that occur over a range of just a few degrees. This difference can have a major effect on measurements by satellite, which provide information on the extent and thickness of sea ice. Results about sea ice will not only make satellite measurements more reliable, but they can also be applied to descriptions of lung and bone porosity, and to understanding ice on other planets. Image: Pancake ice in Antarctica, courtesy of Ken Golden. For More Information: "Thermal evolution of permeability and microstructure in sea ice," K. M. Golden, et al., Geophysical Research Letters, August 28, 2007.