1,857 research outputs found
Histone H1 binding to nucleosome arrays depends on linker DNA length and trajectory
No full textThroughout the genome, nucleosomes often form regular arrays that differ in nucleosome repeat length (NRL), occupancy of linker histone H1 and transcriptional activity. Here, we report cryo-EM structures of human H1-containing tetranucleosome arrays with four physiologically relevant NRLs. The structures show a zig-zag arrangement of nucleosomes, with nucleosomes 1 and 3 forming a stack. H1 binding to stacked nucleosomes depends on the NRL, whereas H1 always binds to the non-stacked nucleosomes 2 and 4. Short NRLs lead to altered trajectories of linker DNA, and these altered trajectories sterically impair H1 binding to the stacked nucleosomes in our structures. As the NRL increases, linker DNA trajectories relax, enabling H1 contacts and binding. Our results provide an explanation for why arrays with short NRLs are depleted of H1 and suited for transcription, whereas arrays with long NRLs show full H1 occupancy and can form transcriptionally silent heterochromatin regions
Author response: The structure of the COPI coat determined within the cell
No full textCOPI-coated vesicles mediate trafficking within the Golgi apparatus and from the Golgi to the endoplasmic reticulum. The structures of membrane protein coats, including COPI, have been extensively studied with in vitro reconstitution systems using purified components. Previously we have determined a complete structural model of the in vitro reconstituted COPI coat (Dodonova et al., 2017). Here, we applied cryo-focused ion beam milling, cryo-electron tomography and subtomogram averaging to determine the native structure of the COPI coat within vitrified Chlamydomonas reinhardtii cells. The native algal structure resembles the in vitro mammalian structure, but additionally reveals cargo bound beneath beta'-COP. We find that all coat components disassemble simultaneously and relatively rapidly after budding. Structural analysis in situ, maintaining Golgi topology, shows that vesicles change their size, membrane thickness, and cargo content as they progress from cis to trans, but the structure of the coat machinery remains constant
Nucleosome-bound SOX2 and SOX11 structures elucidate pioneer factor function
No full text'Pioneer’ transcription factors are required for stem-cell pluripotency, cell differentiation and cell reprogramming1,2. Pioneer factors can bind nucleosomal DNA to enable gene expression from regions of the genome with closed chromatin. SOX2 is a prominent pioneer factor that is essential for pluripotency and self-renewal of embryonic stem cells3. Here we report cryo-electron microscopy structures of the DNA-binding domains of SOX2 and its close homologue SOX11 bound to nucleosomes. The structures show that SOX factors can bind and locally distort DNA at superhelical location 2. The factors also facilitate detachment of terminal nucleosomal DNA from the histone octamer, which increases DNA accessibility. SOX-factor binding to the nucleosome can also lead to a repositioning of the N-terminal tail of histone H4 that includes residue lysine 16. We speculate that this repositioning is incompatible with higher-order nucleosome stacking, which involves contacts of the H4 tail with a neighbouring nucleosome. Our results indicate that pioneer transcription factors can use binding energy to initiate chromatin opening, and thereby facilitate nucleosome remodelling and subsequent transcription
A latent growth curve (LGC) analysis to model Task Demands and the Worst Performance Rule simultaneously
No full textОсновы инновационного развития логистической системы торгового предприятия
No full textDodonova E. O. Fundamentals of the innovative development of the logistics system of a trading compan
Respublikinės studentų mokslinės konferencijos "Chemija ir cheminė technologija 2019" pranešimų medžiaga
No full textScientific Committee:Prof. A. Beganskienė, VUDoc./Assoc. Prof. J. Dodonova, VUProf. V. Getautis, KTUProf. S. Grigalevičius, KTUDoc./Assoc. Prof. T. Paulauskienė, KUProf. S. Tumkevičius, VUProf. A. Žukauskaitė, KU Organizers:Prof. S. Tumkevičius (Chairman), VUG. Inkrataitė (secretary), VUDr. R. Vaitkus, VUDr. S. Višniakova, VUI. Gabriūnaitė, VUL. Sinušaitė, VUM. Steponavičiūtė, VUM. Vagner, VUO. Safinas, VU SAL. Daumantas, VUMokslo komitetas:Prof. A. Beganskienė, VUDoc./Assoc. Prof. J. Dodonova, VUProf. V. Getautis, KTUProf. S. Grigalevičius, KTUDoc./Assoc. Prof. T. Paulauskienė, KUProf. S. Tumkevičius, VUProf. A. Žukauskaitė, KU Organizatoriai:Prof. S. Tumkevičius (pirmininkas), VUG. Inkrataitė (sekretorė), VUDr. R. Vaitkus, VUDr. S. Višniakova, VUI. Gabriūnaitė, VUL. Sinušaitė, VUM. Steponavičiūtė, VUM. Vagner, VUO. Safinas, VU SAL. Daumantas, V
A latent growth curve (LGC) analysis to dissociate components of response-time (RT) variance
No full textRisk Aversion, Managerial Reputation, and Debt–Equity Conflict
No full textWhen a firm finances a new project by issuing debt, it has an incentive to invest in excessively high-risk projects because shareholders enjoy all the benefits in case the project is successful but have limited liability when it fails. Anticipating such behavior, creditors may require a higher interest rate or may even refuse to provide capital. This debt–equity conflict is alleviated by the fact that most investment decisions are made by risk-averse managers who are not as well diversified as shareholders. This paper investigates the debt–equity conflict in firms in which the managers have an unobservable degree of risk averseness. Since managerial risk averseness is a desirable quality, such asymmetric information makes managers undertake actions that increase the market’s perception of them as being highly risk-averse. Consequently, such reputation building leads to a lower number of excessively high-risk projects being undertaken. This paper compares the entrepreneurial economy, in which managers are the sole owners of the firms, with the corporate economy, in which managers are hired by shareholders. Using the overlapping generations model, this paper shows that managerial reputation building can partially resolve the debt–equity conflict and improve efficiency in both economies; however, such improvement is larger in the entrepreneurial economy
Kinetics of growth of new phases during hydrogen-induced transformations in Sm2Fe17 hard magnetic alloy
No full textРыбалка Сергей Борисович – кандидат физико-математических наук, доцент, кафедра физики, физико-металлургический факультет, Донецкий национальный технический университет. e-mail: [email protected]. Додонова Елена Викторовна – магистр, аспирант, кафедра физики, физико-металлургический факультет, Донецкий национальный технический университет. Скоков Константин Петрович – кандидат физико-математических наук, доцент, кафедра магнетизма, физико-технический факультет, Тверской государственный университет. Rybalka Sergey Borisovich is Cand. Sc. (Physics and Mathematics), Associate Professor, Physics Department, Donetsk National Technical University. e-mail: [email protected]. Dodonova Elena Victorovna is a master student, Post-graduate Student, Physics Department, Physics and Metallurgic Faculty, Donetsk National Technical University. Skokov Konstantin Petrovich is Cand. Sc. (Physics and Mathematics), Associate Professor, Magnetism Department, Physics and Technical Faculty, Tver State University.Исследована кинетика роста новых фаз в ходе индуцированного водородом прямого фазового превращения в сплаве Sm2Fe17. Показано, что развитие прямого фазового превращения замедляется с понижением температуры превращения. Анализ кинетики роста новых фаз в ходе индуцированных водородом прямого фазового превращения в сплаве Sm2Fe17 позволил установить, что процесс роста новых фаз в исследованном интервале температур контролируется диффузией больших атомов (Fe, Sm) компонентов сплава. There kinetics of growth of new phases during hydrogen-induced direct phase transformation in Sm2Fe17 alloy was analysed. It is shown that evolution of direct phase transformation decreases with temperature transformation decreasing. Analysis of kinetics of growth of new phases during hydrogeninduced direct phase transformations in Sm2Fe17 alloy allowed to establishe that the process of new phases growth in analysed temperature interval is controlled by diffusion of big atoms of alloy’s components (Fe, Sm)
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